Pasteurella

J Vet Med Sci, 2000 Jan, 62(1), 49 - 52
Decreased apolipoprotein C-III concentration in the high-density lipoprotein fraction from calves inoculated with Pasteurella haemolytica and bovine herpes virus-1; Yamamoto M et al.; Lipoprotein lipid and apoprotein concentrations are known to be altered during the acute-phase response . We have previously shown that the serum activity of lecithin:cholesterol acyltransferase (LCAT) and concentration of cholesteryl esters, both constituents of the high-density lipoprotein (HDL) fraction, are reduced in calves inoculated with Pasteurella haemolytica and bovine herpes virus-1, the two major pathogens for calf pneumonia . The concentration of apolipoprotein C-III (apoC-III), a low molecular mass protein component distributed mainly in the HDL fraction, was therefore examined in bacteria- and virus-inoculated calves . An enzyme-linked immunosorbent assay demonstrated that it was decreased by inoculations of Pasteurella haemolytica and bovine herpes virus-1 . The decrease was detected as early as 1 day after inoculation in both groups . A decreased serum apoC-III concentration was also observed by immunoblot analysis . It was detected in the HDL fractions from the bacteria- and virus-inoculated calves, and HDL apoC-III concentrations in the inoculated calves were decreased compared with controls . These results, coupled with the previous findings on LCAT activity and the cholesteryl ester concentration, indicate that a decreased HDL concentration is one of the early events occurring during the acute-phase response evoked by infections with Pasteurella haemolytica and bovine herpes virus-1.

J Vet Med Sci, 2000 Jan, 62(1), 37 - 41
Detection of annexins I and IV in bronchoalveolar lavage fluids from calves inoculated with bovine herpes virus-1; Katoh N; Annexins are phospholipid-binding proteins and are abundant in the lung . Annexins I and IV, but not II and VI, have been detected in bronchoalveolar lavage (BAL) fluids from calves inoculated with Pasteurella haemolytica, the pathogen for calf pneumonia . In this study, BAL fluids from calves with experimental pneumonia induced by inoculation to right lung lobes of bovine herpes virus-1 (BHV-1), the major viral pathogen for pneumonia, were examined for detection of annexins I and IV . Of 6 calves inoculated with BHV-1, annexins I and IV were coincidentally detected in BAL fluids from right lung lobes of 4 calves, but not in BAL fluids from left lung lobes of 6 inoculated calves or those from left and right lung lobes of 3 control calves . Annexin II and VI were not found in any BAL fluids examined . These results, together with previous findings on calves inoculated with Pasteurella haemolytica, suggest that the release of annexins I and IV onto the alveolar surface is an essential event occurring in response to pulmonary infections of BHIV-1 and Pasteurella haemolytica.

Vet Res Commun, 1999 Dec, 23(8), 467 - 73
The effects of dexamethasone on the response of bronchus-associated lymphoid tissue to intranasal administration of formalin-killed Pasteurella haemolytica A2 in goats; Zamri-Saad M et al.; A trial was conducted to observe the immediate and chronic effects in goats of dexamethasone administration on the bronchus-associated lymphoid tissue (BALT) response to intranasal administration of formalin-killed Pasteurella haemolytica A2 . Twenty-four goats were divided into four groups . Those in group 1 were injected intramuscularly with 1 mg/kg dexamethasone on three consecutive days, followed by intranasal exposure to formalin-killed P . haemolytica A2 one day after the last dexamethasone treatment . The goats in group 2 were similarly injected with dexamethasone followed by intranasal exposure to formalin-killed P . haemolytica A2 21 days after the last dexamethasone treatment . The animals in group 3 were exposed intranasally to formalin-killed P . haemolytica A2 without prior dexamethasone treatment . The animals in group 4 were untreated controls . The intranasal exposures to formalin-killed P . haemolytica A2 were repeated 2 weeks later . Intranasal exposure to formalin-killed P . haemolytica 1 day after dexamethasone treatment further reduced the number and size of BALT compared to the untreated control . Significantly (p < 0.01) more reduction of BALT occurred in goats exposed to formalin-killed P . haemolytica A2 21 days after dexamethasone treatment . On the other hand, intranasal exposure of goats without prior dexamethasone treatment stimulated the BALT compared to the untreated controls.

Prev Vet Med, 2000 Jan 5, 43(1), 29 - 42
A stochastic partial-budget analysis of an experimental Pasteurella haemolytica feedlot vaccine trial; Gummow B et al.; A field trial compared a modified Pasteurella haemolytica biotype A serotype 1 leukotoxin vaccine to a commercial vaccine during March-July 1995 in a Natal Midlands, South African, feedlot . Weaners/long weaners purchased by the feedlot were allocated systematically into test vaccine and control vaccine groups of 1241 and 1240 head, respectively, and fed in groups of approximately 200 head . Morbidity and mortality were monitored until the animals were marketed . Details of pleuritis and pneumonia at veterinary meat inspection were recorded for 409 test-vaccinated and 424 control-vaccinated cattle . An increase in morbidity but not mortality risk of respiratory disease was shown between test (13.8% morbidity) and control (11.4% morbidity) groups . Cattle with a processing weight <245 kg were 1.4 times more likely to develop respiratory diseases than cattle with a processing weight > or =245 kg . Cattle bought on auction were 1.6 times more likely to develop respiratory disease than cattle bought at private sales . A partial farm budget incorporating Latin Hypercube sampling of uncertain variables was done to obtain the distribution of possible financial outcomes if the test vaccine were used . Impact (sensitivity) analyses indicated that median weight of carcass cut away had the greatest impact on the profit margin . The partial farm budget highlighted the importance of reducing sub-clinical lesions in a feedlot.

J Antibiot (Tokyo), 1999 Nov, 52(11), 1007 - 16
In vitro microbiological characterization of novel cyclic homopentapeptides, CP-101,680 and CP-163,234, for animal health use; Norcia LJ et al.; Two cyclic homopentapeptides, CP-101,680 and CP-163,234 {6a-(3',4'-dichlorophenylamino) analogs of viomycin and capreomycin, respectively}, were identified as novel antibacterial agents for the treatment of animal disease, especially for livestock respiratory disease . The in vitro microbiological characterization of both CP-101,680 and CP-163,234 was carried out using their parent compounds, viomycin and capreomycin, as controls . This characterization included antibacterial spectrum, influence of media, inoculum size, pH, EDTA, polymixin B nonapeptide (PMBN), serum, cell-free protein synthesis inhibition, and time-kill kinetics . Our results indicated that the capreomycin analog, CP-163,234, showed slightly improved in vitro potency over the viomycin analog, CP-101,680 . Both analogs showed very potent cell-free protein synthesis inhibition activity and were bactericidal against Pasteurella haemolytica, P . multocida and Actinobacillus pleuropneumoniae at the level of 4 times and 8 times MICs . CP-163,234 was bactericidal at the level of 4x and 8x MIC against E . coli, but re-growth was observed after 24 hours incubation at both concentrations of CP-101,680.

J Biol Chem, 2000 Jan 21, 275(3), 2239 - 45
Pasteurella multocida toxin stimulates mitogen-activated protein kinase via G(q/11)-dependent transactivation of the epidermal growth factor receptor; Seo B et al.; The dermatonecrotic toxin produced by Pasteurella multocida is one of the most potent mitogenic substances known for fibroblasts in vitro . Exposure to recombinant P . multocida toxin (rPMT) causes phospholipase C-mediated hydrolysis of inositol phospholipids, calcium mobilization, and activation of protein kinase C via a poorly characterized mechanism involving G(q/11) family heterotrimeric G proteins . To determine whether the regulation of G protein pathways contributes to the mitogenic effects of rPMT, we have examined the mechanism whereby rPMT stimulates the Erk mitogen-activated protein kinase cascade in cultured HEK-293 cells . Treatment with rPMT resulted in a dose and time-dependent increase in Erk 1/2 phosphorylation that paralleled its stimulation of inositol phospholipid hydrolysis . Both rPMT- and alpha-thrombin receptor- stimulated Erk phosphorylation were selectively blocked by cellular expression of two peptide inhibitors of G(q/11) signaling, the dominant negative mutant G protein-coupled receptor kinase, GRK2(K220R), and the Galpha(q) carboxyl-terminal peptide, Galpha(q)-(305-359) . Like alpha-thrombin receptor-mediated Erk activation, the effect of rPMT was insensitive to the protein kinase C inhibitor GF109203X, but was blocked by the epidermal growth factor receptor-specific tyrphostin, AG1478 and by dominant negative mutants of mSos1 and Ha-Ras . These data indicate that rPMT employs G(q/11) family heterotrimeric G proteins to induce Ras-dependent Erk activation via protein kinase C-independent "transactivation" of the epidermal growth factor receptor.

Acta Med Okayama, 1999 Dec, 53(6), 245 - 52
Genomic structure of the rat major AP endonuclease gene (Apex) with an adjacent putative O-sialoglycoprotease gene (Prsmg1/Gcpl1) and a processed Apex pseudogene (Apexp1); Yao M et al.; Genomic sequencing and chromosomal assignment of the gene encoding rat APEX nuclease, a multifunctional DNA repair enzyme, were performed . An active Apex gene and a processed pseudogene were isolated from a rat genomic library . The active Apex gene consists of 5 exons and 4 introns spanning 2.1 kb . The putative promoter region of the Apex gene lacks the typical TATA box, but contains CAAT boxes and a CpG island having putative binding sites for several transcription factors, such as Sp1, AP-2, GATA-1 and ATF . A putative O-sialoglycoprotease (a homologue of Pasteurella haemolytica glycoprotease, gcp; abbreviated as Prsmg1/Gcpl1) gene consisting of 11 exons and 10 introns spanning 7.3 kb lies immediately adjacent to the Apex gene in a 5'-to-5' orientation . The Apex gene locus was mapped to rat chromosome 15p12 using in situ hybridization . The processed pseudogene (designated as rat Apexp1) has a nucleotide sequence 87.1% identical to that of the rat Apex cDNA, although several stop codons interrupting the coding sequences and multiple nucleotide deletions were observed . The Apexp1 is located in an inactive LINE sequence . Calculation of nucleotide substitution rates suggests that the immediate, active progenitor of Apexp1 arose 23 million years ago and that the non-functionalization occurred 15 million years ago.

Am J Vet Res, 2000 Jan, 61(1), 51 - 6
Ultrastructural characterization of apoptosis in bovine lymphocytes exposed to Pasteurella haemolytica leukotoxin; Sun Y et al.; OBJECTIVE: To characterize ultrastructural changes of bovine lymphocytes exposed to Pasteurella haemolytica leukotoxin (LKT) . SAMPLE POPULATION: Partially purified LKT from a wild type P . haemolytica A1 strain and inactive pro-LKT from an isogeneic mutant Phaemolytica strain . Isolated bovine lymphocytes were obtained from 2 healthy calves . PROCEDURE: Isolated bovine lymphocytes were incubated with various concentrations of LKT and pro-LKT for 3 hours at 37 C and examined by use of transmission electron microscopy . A cytochemical Klenow DNA fragmentation assay was used to examine lymphocytes for DNA fragmentation . RESULTS: Lymphocytes incubated with LKT at a high concentration (1.0 toxic U/ml) had ultrastructural evidence of cytoplasmic and nuclear membrane rupture and swelling or lysis of mitochondria . Low concentrations of leukotoxin (0.1 toxic U/ml) induced DNA fragmentation in 80% of lymphocytes . Ultrastructurally, these cells had nuclear membrane blebbing, cytoplasmic vaculation, chromatin condensation, nuclear fragmentation, and membrane-bound apoptotic bodies . Incubation of lymphocytes with LKT at extremely low concentrations (0.001 toxic U/ml) or with pro-LKT did not alter their ultrastructure . Inclusion of 0.5 mM ZnCl2 in the medium blocked leukotoxin-induced ultrastructural changes in bovine lymphocytes . CONCLUSIONS AND CLINICAL RELEVANCE: Low concentrations of LKT induce apoptosis and high concentrations induce oncotic cell lysis in bovine lymphocytes . The ability of low LKT concentrations to induce apoptosis in host leukocytes may allow bacteria to escape host immune surveillance and colonize the host.

J Med Microbiol, 2000 Jan, 49(1), 81 - 7
Restriction endonuclease analysis using Hhal and Hpall to discriminate among group B Pasteurella multocida associated with haemorrhagic septicaemia; Rimler RB; The purpose of this study was to improve and standardise restriction endonuclease analysis (REA) for discriminating isolates of serogroup B Pasteurella multocida associated with haemorrhagic septicaemia in wild and domestic animals and to create a reference database that can be used for epidemiological studies . Two techniques for extraction and isolation of chromosomal DNA were compared, a DNAzol method and an enzymic lysis followed by a two-phase partition method . No differences were observed between DNA fingerprint profiles with either technique; however, the former technique was faster and easier to perform . P . multocida isolated from different animals in different countries representing serotypes B:2, B:3, B:3,4 and B:4 were subjected to REA with HhaI and HpaII endonucleases . Forty-eight fingerprint profiles were distinguished among 222 isolates when only HhaI was used . By combining the data from REA with HhaI and HpaII used separately, 88 different groups could be distinguished among the same isolates . Following digestion with HhaI and electrophoresis, the DNA of all serotype B:2 isolates produced fingerprint profiles characterised by two trailing bands at approximately 8.4-7.1 kb which have not been observed in any other serotypes of P . multocida . Passage of three serotype B:2 isolates on laboratory media or two serotype B:2 isolates through mice did not result in a change of DNA fingerprint profile detectable by REA . The findings with 59 isolates from Sri Lanka showed that REA was highly discriminative in determining the genetic diversity of serotype B:2 P . multocida in an area where haemorrhagic septicaemia is endemic.

Crit Care Med, 1999 Dec, 27(12), 2741 - 7
The risk of nosocomial pneumonia is not increased during partial liquid ventilation; Sajan I et al.; OBJECTIVE: To determine whether partial liquid ventilation (PLV) affects the risk of nosocomial pneumonia . STUDY DESIGN: To assess in vitro bacterial adhesion and viability after liquid perfluorocarbon exposure and to assess bacterial recovery after partial liquid ventilation in vivo in rabbits . SETTING: University animal research facility . SUBJECTS: Thirty-six New Zealand White rabbits . INTERVENTIONS: To assess adhesions, radiolabeled Escherichia coli were exposed to perfluorocarbon, incubated against artificial biosurfaces, and compared with nonexposed controls . Bacterial viability in vitro was assessed by exposing broth suspensions of Pasteurella multocida to perflubron for various times . Controls were run in parallel without exposure . Quantitative cultures were performed to determine viability . We undertook short-term and recovery in vivo investigations . The lungs of treated animals were filled with perflubron (approximately 18 mL/kg), and the control rabbits were ventilated without perflubron in an identical fashion . Cryopreserved aliquots of P . multocida were administered via an endotracheal tube . The short-term study animals were ventilated for 6 hrs before being killed . The recovery animals were ventilated for 2-4 hrs, extubated, and killed 20 hrs later . The lungs were removed, aseptically minced, and homogenized . Serial dilutions of the homogenate were quantitatively cultured by manual counting of colonies on agar plates . The recovered organisms were typed for species by the clinical microbiology laboratory . MEASUREMENTS AND MAIN RESULTS: The adhesion of bacteria to immobilized bronchoalveolar lavage and human saliva, respectively, was reduced by 65%+/-7% and 66%+/-1% (p < .05; n = 5) after exposure to perflubron and by 63%+/-9% and 68%+/-6% after exposure to FC-77 (p < .05; n = 5); however, adhesion was not affected by exposure to Rimar . There was no difference in bacterial viability between the control and perflubron-exposed bacteria (n = 5) . The in vivo study demonstrated a ten-fold or greater reduction in the number of recovered bacteria in the partial liquid ventilated group compared with the control group . CONCLUSIONS: This study suggests that different perfluorocarbons affect adhesions differently . Perflubron and FC-77 appear to decrease bacterial adhesion, whereas Rimar does not . Rerflubron does not have a direct bactericidal effect . Furthermore, PLV with perflubron decreased the number of viable bacteria per gram of tissue after an intentional inoculation of the airway, suggesting that the risk of nosocomial pneumonia is unlikely to be increased during PLV and may, in fact, be reduced in patients supported with PLV.

J Clin Microbiol, 2000 Jan, 38(1), 327 - 32
Comparison of Pasteurella spp . simultaneously isolated from nasal and transtracheal swabs from cattle with clinical signs of bovine respiratory disease; DeRosa DC et al.; Twenty-four matched pairs of isolates of Pasteurella haemolytica and three matched pairs of isolates of Pasteurella multocida were isolated by using a nasal swab and a transtracheal swab from individual calves with clinical signs of bovine respiratory disease . The identity of each matched pair was confirmed biochemically and serologically . The similarity of the isolates obtained from a nasal swab and from a transtracheal swab was compared by using ribotyping and antibiotic susceptibility analyses . Although the calves were sampled only once with a nasal and a transtracheal swab, when both samples were bacteriologically positive the nasal swab identified the same bacterial species as the transtracheal swab 96% of the time . The nasal swab isolate was genetically identical to the transtracheal isolate in 70% of the matched pairs . Six different ribotypes were observed for the P . haemolytica isolates, while only one ribotype was observed for the limited number of P . multocida isolates . Of the six P . haemolytica ribotypes, two ribotypes predominated . All the paired isolates displayed similar susceptibility to ceftiofur, erythromycin, tilmicosin, trimethoprim-sulfamethoxazole, and florfenicol, with some minor variations for ampicillin and spectinomycin . These results suggest that a nasal swab culture can be predictive of the bacterial pathogen within the lung when the isolates are from an acutely ill animal and can be used to determine antibiotic susceptibility.

Plasmid, 2000 Jan, 43(1), 99 - 102
Complete nucleotide sequence of a cryptic plasmid from the marine bacterium Vibrio splendidus and identification of open reading frames; Powers LG et al.; A 2.3-kb replication-proficient fragment was previously obtained from a cryptic plasmid (pPS41) isolated from a marine Vibrio splendidus isolate (P . A . Sobecky, T . J . Mincer, M . C . Chang, A . Toukdarian, and D . R . Helinski, 1998, Appl . Environ . Microbiol . 64, 2822-2830) . Analysis of the complete nucleotide sequence of plasmid pPS41 revealed two additional open reading frames (ORFs) . Analysis of ORF-1 revealed that its translated product has 125 amino acids with a predicted MW of 16,978 and ORF-2 encodes a putative protein of 151 amino acids with a predicted MW of 19,802 . The ORF-2 encoded protein showed 31 to 35% sequence homology to proteins identified to have a role in plasmid mobilization . These proteins are encoded on plasmids found in Escherichia coli and Pasteurella multocida . Plasmid pPS41 could be mobilized by a conjugative plasmid at frequencies of 1 x 10(-2) to 2 x 10(-2) .

Acta Vet Scand, 1999, 40(3), 197 - 203
Effect of aerial ammonia on porcine infection of the respiratory tract with toxigenic Pasteurella multocida; Andreasen M et al.; The objective of the experimental study was to examine whether aerial ammonia alone could predispose the respiratory system of pigs to infection with toxigenic Pasteurella multocida type A . Two groups of 5 pigs each were continuously exposed to 50 ppm ammonia and less than 5 ppm ammonia, respectively, for a 59-day period (from 37 kg to 90 kg bodyweight) followed by necropsy . In an aerosol chamber all pigs were exposed to an aerosol of toxigenic P . multocida type A (mean bacterial concentration in the aerosol-exposure chamber: 10(5) colony forming units/m3; exposure period: 25 min) at day 10, 21, 35 and 49 after the onset of ammonia exposure . During the experiment none of the pigs showed clinical signs of pneumonia nor did they develop visible distortion of the snout . None of the pigs had gross lesions in the lungs at necropsy and toxigenic P . multocida was not detected by culture from the lungs from any of the pigs . The chance of recovering toxigenic P . multocida from nasal swabs (collected during experiment) was 2-4 times greater in the test group compared to the control group . The average daily weight gain was lower for the ammonia exposed pigs compared to the control group . In conclusion the results from this study suggest that ammonia in concentrations of 50 ppm is unlikely to predispose growing pigs to pulmonary infection with toxigenic P . multocida.

Infect Immun, 2000 Jan, 68(1), 72 - 9
Lymphocyte function-associated antigen 1 is a receptor for Pasteurella haemolytica leukotoxin in bovine leukocytes; Jeyaseelan S et al.; Pasteurella (Mannheimia) haemolytica leukotoxin (Lkt) causes cell type- and species-specific effects in ruminant leukocytes . Recent studies indicate that P . haemolytica Lkt binds to bovine CD18, the common subunit of all beta2 integrins . We designed experiments with the following objectives: to identify which member of the beta2 integrins is a receptor for Lkt; to determine whether Lkt binding to the receptor is target cell (bovine leukocytes) specific; to define the relationships between Lkt binding to the receptor, calcium elevation, and cytolysis; and to determine whether a correlation exists between Lkt receptor expression and the magnitude of target cell cytolysis . We compared Lkt-induced cytolysis in neutrophils from control calves and from calves with bovine leukocyte adhesion deficiency (BLAD), because neutrophils from BLAD-homozygous calves exhibit reduced beta2 integrin expression . The results demonstrate for the first time that Lkt binds to bovine CD11a and CD18 (lymphocyte function-associated antigen 1 {LFA-1}) . The binding was abolished by anti-CD11a or anti-CD18 monoclonal antibody (MAb) . Lkt-induced calcium elevation in bovine alveolar macrophages (BAMs) was inhibited by anti-CD11a or anti-CD18 MAb (65 to 94% and 37 to 98%, respectively, at 5 and 50 Lkt units per ml; P < 0.05) . Lkt-induced cytolysis in neutrophils and BAMs was also inhibited by anti-CD11a or anti-CD18 MAb in a concentration-dependent manner . Lkt bound to porcine LFA-1 but did not induce calcium elevation or cytolysis . In neutrophils from BLAD calves, Lkt-induced cytolysis was decreased by 44% compared to that of neutrophils from control calves (P < 0.05) . These results indicate that LFA-1 is a Lkt receptor, Lkt binding to LFA-1 is not target cell specific, Lkt binding to bovine LFA-1 correlates with calcium elevation and cytolysis, and bovine LFA-1 expression correlates with the magnitude of Lkt-induced target cell cytolysis.

Infect Immun, 2000 Jan, 68(1), 6 - 12
Characterization of PaxA and its operon: a cohemolytic RTX toxin determinant from pathogenic Pasteurella aerogenes; Kuhnert P et al.; Pasteurella aerogenes is known as a commensal bacterium or as an opportunistic pathogen, as well as a primary pathogen found to be involved in abortion cases of humans, swine, and other mammals . Using broad-range DNA probes for bacterial RTX toxin genes, we cloned and subsequently sequenced a new operon named paxCABD encoding the RTX toxin PaxA in P . aerogenes . The pax operon is organized analogous to the classical RTX operons containing the activator gene paxC upstream of the structural toxin gene paxA, which is followed by the secretion protein genes paxB and paxD . The highest sequence similarity of paxA with known RTX toxin genes is found with apxIIIA (82%) . PaxA is structurally similar to ApxIIIA and also shows functional analogy to ApxIIIA, since it shows cohemolytic activity with the sphingomyelinase of Staphylococcus aureus, known as the CAMP effect, but is devoid of direct hemolytic activity . In addition, it shows to some extent immunological cross-reactions with ApxIIIA . P . aerogenes isolated from various specimens showed that the pax operon was present in about one-third of the strains . All of the pax-positive strains were specifically related to swine abortion cases or septicemia of newborn piglets . These strains were also shown to produce the PaxA toxin as determined by the CAMP phenomenon, whereas none of the pax-negative strains did . This indicated that the PaxA toxin is involved in the pathogenic potential of P . aerogenes . The examined P . aerogenes isolates were phylogenetically analyzed by 16S rRNA gene (rrs) sequencing in order to confirm their species . Only a small heterogeneity (<0.5%) was observed between the rrs genes of the strains originating from geographically distant farms and isolated at different times.

Trop Anim Health Prod, 1999 Dec, 31(6), 333 - 45
Studies on the respiratory disease 'sonbobe' in camels in the eastern lowlands of Ethiopia; Bekele T; New epidemics of respiratory disease have caused 29.6 morbidity and 6.4% mortality in camels in the Somalia region of Ethiopia . The major clinical signs observed were fever of 40-41.5 degrees C, depression, cough, loss of appetite and a watery nasal discharge that became mucopurulent at a later stage . Finally, the camel became recumbent and extended its neck straight along the ground . Some of the animals died within 8-9 days . The major post-mortem lesions were hydrothorax, adhesion of the lung to the thorax, red and grey hepatization, emphysema, hydropericardium and fibrinous pericarditis . A treatment trial indicated that oxytetracycline was more effective than a combination of penicillin and streptomycin, the results showing a significant difference (p < 0.05) between the treated and control groups . The bacteria isolated from lung, thoracic fluid and whole blood were Pasteurella haemolytica . Further studies on the epidemiology of this disease, the identification of the serotypes involved, and the demonstration of any primary viral initiating agent are recommended to allow the development of preventive methods.

Am J Ophthalmol, 1999 Oct, 128(4), 514 - 5
Periocular abscess and cellulitis from Pasteurella multocida in a healthy child; Hutcheson KA et al.; PURPOSE: To examine an unusual cause of periorbital cellulitis, Pasteurella multocida . METHODS: Case report, review of the literature . RESULTS: We treated a 13-year-old previously healthy child who developed Pasteurella preseptal cellulitis secondary to a cat bite and cat scratch . After receiving a dose of intravenous antibiotics and starting oral antibiotics, the child had delayed onset of several abscesses around the right eye, with marked pain and erythema . After incision and drainage, he improved . CONCLUSION: Pasteurella multocida is a rare but potentially serious cause of ocular infection . All cases of potential exposure should be treated promptly and followed until complete resolution of infection.

Glycobiology, 2000 Jan, 10(1), 31 - 7
Purification and characterization of an adhesin from Pasteurella haemolytica; Jaramillo L et al.; We purified an adhesin from Pasteurella . haemolytica by affinity chromatography using glutaraldehyde treated rabbit erythrocytes stroma . The adhesin is a protein of 68 kDa, as determined by SDS-PAGE, and the most abundant amino acids constituting this protein were Gly, Ser, Glx, and Ala, and low concentrations of Cys, Met, and Tyr residues were also found . The N-terminal sequence of the adhesin is ANEVNVYIYKQPYLI . No carbohydrate residues were detected . The adhesin agglutinated rabbit erythrocytes but when the latter were desialylated or pronase treated the agglutinating activity was abolished . The agglutinating activity of the adhesin was inhibited with N-acetyl-D-glucosamine (GlcNAc), and in a lesser degree with N-acetyl-neuraminic acid (NeuAc) . GalNAc, N-glycolyl-neuraminic acid, N-deacetylated GlcNAc, or neutral sugars do not modify the activity of the adhesin . The equatorial -OH on C4 and the NH-acetylated group on C2 from GlcNAc, as well as the 4-OH and NH-acetylated group on C5 from NeuAc seem to be responsible for the interaction with the adhesin . The protein is divalent cation-dependent and thermolabile . As for the agglutinating activity, the adhesion of P.haemolytica to tracheal cell-cultures was inhibited by GlcNAc, NeuAc or the purified adhesin, strongly suggesting that the P.haemolytica adhesin plays an important role in infection.

Infect Immun, 1999 Dec, 67(12), 6264 - 9
Correlation of Pasteurella haemolytica leukotoxin binding with susceptibility to intoxication of lymphoid cells from various species; Sun Y et al.; Pasteurella haemolytica, the causative agent of shipping fever pneumonia in cattle, produces a leukotoxin (LKT) which lyses ruminant leukocytes with high efficiency but is reputed to not affect leukocytes from nonruminant species . In this study, we tested the supposition that LKT binding correlates positively with susceptibility to intoxication of susceptible isolated bovine lymphocytes and lymphoma tissue culture cells (BL3 cells) and negatively with reputed nonsusceptible equine, porcine, and canine lymphocytes and human lymphoid tissue culture cells (Raji cells) . Bovine lymphocytes and BL3 cells were highly susceptible to LKT intoxication, exhibiting both substantial increase in intracellular Ca(2+) concentration and marked leukolysis . Exposure of reputed LKT-nonsusceptible porcine lymphocytes and Raji cells to LKT caused a slightly increased intracellular Ca(2+) concentration but no leukolysis . No LKT effect was detected for equine and canine lymphocytes . LKT bound to lymphoid cells from all species tested . Intact 102-kDa LKT was recovered from exposed isolated lymphoid cell membranes . Pro-LKT acylation was not required for LKT binding to BL3 cells . LKT binding was rapid, with maximal binding occurring by 3 min, and was proportional to the LKT concentration in the range 0.04 to 4.0 microg/ml . For this LKT concentration range, BL3 cells bound more LKT than did porcine lymphocytes or Raji cells, suggesting that LKT binds to BL3 cells with higher affinity than to porcine lymphocytes or Raji cells . Above 4.0 microg/ml, LKT demonstrated saturable binding to BL3 cells . Neutralizing anti-LKT monoclonal antibody (MAb) MM601 diminished LKT binding to BL3 by 36% while decreasing leukolysis by 81% . In contrast, MM601 did not diminish LKT binding to Raji cells . Pretreatment of target cells with 120 microg of protease K per ml diminished LKT binding to BL3 cells by 75%, with only a 25% decrease in leukolysis . However, pretreatment with 150 microg of protease K per ml abolished the remaining 25% of LKT binding and 75% leukolysis . Therefore, P . haemolytica LKT binds rapidly to susceptible and to reputed nonsusceptible lymphoid cells . LKT binding resulting in species-specific leukolysis was characterized by high affinity, inhibition by MAb MM601, and relative resistance to protease K pretreatment of lymphoid cells . Two types of LKT binding to lymphoid cells are proposed . High-affinity binding leads to efficient leukolysis . In some lymphoid cells from reputed LKT-nonsusceptible species, low-affinity LKT binding may cause a low-efficiency increase in the intracellular Ca(2+) concentration without leading to leukolysis.

Am J Vet Res, 1999 Nov, 60(11), 1402 - 6
Use of a polymerase chain reaction method to detect the leukotoxin gene lktA in biogroup and biovariant isolates of Pasteurella haemolytica and P trehalosi; Fisher MA et al.; OBJECTIVE: To determine whether Pasteurella haemolytica and P trehalosi isolates possess the structural gene for Pasteurella leukotoxin lktA and whether beta-hemolytic activity of these isolates correlated with detection of the lktA gene . SAMPLE POPULATION: 147 P haemolytica isolates from 21 biovariant groups and 101 P trehalosi isolates from 7 biovariant groups . In addition, P multocida and organisms from 7 other genera were tested to establish specificity of the procedure . PROCEDURE: Isolates were observed for beta-hemolysis . A polymerase chain reaction (PCR) procedure was used to amplify the RTX domain of the Pasteurella lktA gene . RESULTS: The lktA gene was detected in 108 (44%) isolates, including 15 associated with respiratory tract disease . All but 2 (98%) of the isolates that had the lktA gene were beta-hemolytic when grown on sheep blood agar . The remaining 140 isolates were negative for the lktA gene and hemolytic activity . CONCLUSIONS AND CLINICAL RELEVANCE: Hemolytic activity of P haemolytica and P trehalosi isolates correlated with detection of the lktA gene for all but 2 isolates . However, 56% of isolates tested were negative for the lktA gene and beta-hemolytic activity . Leukotoxin production and secretion is a major virulence factor when other conditions are favorable for disease development . Therefore, identification of strains that possess the lktA gene may aid in the evaluation of the pathogenic potential of Pasteurella strains carried by wild and domestic animals.

Am J Vet Res, 1999 Nov, 60(11), 1390 - 5
Detection of annexin I and IV and haptoglobin in bronchoalveolar lavage fluid from calves experimentally inoculated with Pasteurella haemolytica; Katoh N et al.; OBJECTIVE: To determine whether annexins or haptoglobin could be detected in bronchoalveolar lavage (BAL) fluid specimens obtained from calves experimentally inoculated with Pasteurella haemolytica . ANIMALS: Twelve 2- to 3-month-old male Holstein calves . PROCEDURE: Pasteurella haemolytica was inoculated into the right lung lobes of each of 6 calves . Six other calves received vehicle alone and were used as control calves . Specimens of BAL fluid were obtained from 3 control and 3 inoculated calves 1 day after inoculation and from the other calves 2 days after inoculation . The amount of annexins I, II, IV, and VI, and haptoglobin in BAL fluid specimens was examined by use of immunoblot analysis . RESULTS: Annexins I and IV were detected in BAL fluid specimens obtained from the right lung lobes of each of the inoculated calves, but annexins II and VI were not . Annexin I also was found in BAL fluid specimens obtained from the left lung lobes of each inoculated calf and from left and right lung lobes of the control calves . By comparison, detection of annexin IV was essentially limited to the right lung lobes of inoculated calves . Haptoglobin was detected in some, but not all, BAL fluid specimens from the right lung lobes of inoculated calves, and its detection in BAL fluid was associated with serum proteins such as albumin . CONCLUSIONS AND CLINICAL RELEVANCE: Annexin IV was detected most specifically in response to inoculation of P haemolytica . This protein could be used as a marker for inflammatory pulmonary disease caused by P haemolytica.

Int J Antimicrob Agents, 1999 Sep, 13(1), 47 - 51
Anionic antimicrobial peptide-lysozyme interactions in innate pulmonary immunity; Kalfa VC et al.; The respiratory tract contains numerous antimicrobial factors necessary for normal innate pulmonary defense . Although many of these molecules reside in airway surface liquid (ASL) simultaneously, little information exists concerning antagonistic, additive, or synergistic interactions . Since both cationic lysozyme and anionic antimicrobial peptides (AP) are found in high concentrations in ASL, the purpose of this study was to assess any interaction that might affect antimicrobial activity . For this, Pasteurella haemolytica, Micrococcus lysodeikticus, or Pseudomonas aeruginosa were added to egg white lysozyme (3.9-250.0 microg/ml) or human neutrophil lysozyme (0.8-50.0 microg/ml) and H-GADDDDD-OH (from 0.01 to 0.50 mM) mixtures in 50, 100, or 150 mM NaCl; incubated for 2 h; and then plated . In this assay, the MICs of AP for P . haemolytica, M . lysodeikticus, and P . aeruginosa varied slightly depending upon the concentration of NaCl and MICs generally increased slightly with increasing NaCl concentrations . The MIC of lysozyme for P . haemolytica and M . lysodeikticus also increased slightly with increasing NaCl concentrations . The MIC of lysozyme for P . aeruginosa was greater than 50 microg/ml and did not vary with increasing NaCl concentrations . When AP was combined with lysozyme in 50, 100, or 150 mM NaCl concentrations, there was no significant interaction that affected antimicrobial activity . In conclusion, the MICs of AP generally increased with increasing NaCl concentrations but lysozyme and AP appeared not to interact significantly at physiologically relevant concentrations.

J Vet Med Sci, 1999 Oct, 61(10), 1101 - 6
Reduced serum lecithin:cholesterol acyltransferase activity and cholesteryl ester concentration in calves experimentally inoculated with Pasteurella haemolytica and bovine herpes virus-1; Nakagawa H et al.; Lecithin:cholesterol acyltransferase (LCAT), the enzyme responsible for esterification of cholesterol in plasma, is reported to be implicated in the regulation of inflammation in laboratory animals . The purpose of the present study was to elucidate the possible relevance of LCAT in the pathogenesis of calf pneumonia induced by inoculations of Pasteurella haemolytica and bovine herpes virus-1 into the calf lung . Serum LCAT activity was significantly (P < 0.01) reduced in calves inoculated with Pasteurella haemolytica . The concentration of cholesteryl esters (CE), the product of the LCAT reaction, was also decreased in the inoculated group . Decreases in LCAT activity and the CE concentration were similarly observed in calves in which bovine herpes virus-1 was inoculated . In both bacteria- and virus-inoculated calves, CE concentrations in the high-density lipoprotein fractions were distinctly decreased, whereas those in the low-density lipoprotein fractions were practically unaltered . The acute-phase proteins haptoglobin and serum amyloid A were detected in sera from the bacteria- and virus-inoculated calves; however, the two acute-phase proteins were also found in sera from the control calves . These results suggest that decreases in LCAT activity and the CE concentration are involved in the pathogenesis of pneumonia induced by inoculation of calves with Pasteurella haemolytica and bovine herpes virus-1, and also that the change in the LCAT system is more intimately related to the occurrence of calf pneumonia than the induction of acute-phase proteins such as haptoglobin.

Med Clin (Barc), 1999 Oct 9, 113(11), 415 - 7
{Respiratory pasteurellosis . Description of a first series in Spain}; Ferrer A et al.; OBJECTIVE: To know the clinical and microbiological characteristics of a first series of 8 patients in whom Pasteurella multocida was detected in samples from low respiratory airways . PATIENTS AND METHODS: Patients with respiratory disease who had positive cultures for P . multocida in several biologic samples between 1986 and 1998 were studied . Patient's data were obtained from clinical files; microbiological study included microscopic examination, qualitative culture in all samples and quantitative culture in low respiratory airway samples . RESULTS: P . multocida was detected in 7 males and one female, with a mean age of 63 years (range: 6-71) . All but one had a previous bronchial disease: 5 had chronic obstructive bronchial disease, 2 had bronchiectasis and one had relapsing acute bronchitis . Three patients referred a previous contact with pets . The main diagnosis, at the time P . multocida was detected, was exacerbated bronchitis in 4 patients, pneumonia in 2 (one with sepsis and positive blood culture to P . multocida) and another one with empyema . In the only paediatric patient P . multocida was a casual finding . Two patients died, both having a severe immunosuppression . The percentage of P . multocida detection compared to all low respiratory airway isolates along the study period was 0.02% . All samples were purulent and more than 10(7) P . multocida colony-forming units/millilitre were detected . All strains were penicillin-sensitive . CONCLUSIONS: Pasteurella multocida respiratory infection is rare, although it is probably underestimated owing to the fact that it is difficult to identify when coexisting with oropharingeal flora . Characteristically, in affects old males with bronchial disease are involved and can be life threatening in severely immunosuppressed patients.

Poult Sci, 1999 Nov, 78(11), 1532 - 5
Effect of selection for increased body weight on mitogenic responses in turkeys; Li Z et al.; Mitogenic responses were examined for purified peripheral blood mononuclear cells (PBMC) and whole blood from individuals in a line (F) of turkeys selected for increased 16-wk BW and its corresponding randombred control (RBC2) . The PBMC were isolated by centrifugation over Histopaque-1077 density gradient and tested for mitogenic responses to concanavalin A (Con A; 25 microg/mL) and phytohemagglutinin (PHA)-M; 100 microg/mL) . For the whole blood assay, 6-wk-old poults from both lines were injected with inactivated Pasteurella multocida . Heparinized blood samples were collected prior to injection (0 d) and at 2, 4, 7, and 14 d postinjection . The diluted whole blood was then tested for the mitogenic responses to Con A (25 microg/mL) and PHA-M (25 microg/mL) . The cultures were then pulsed with 3H-thymidine, and incorporation was measured using a liquid scintillation counter . There was a line difference in the mitogenic responses to Con A for PBMC and whole blood assays, but no line difference was observed in the response to PHA-M for both assays . For the purified PBMC assay, the F line had a lower response than its randombred control line (P < or = 0.05) to Con A expressed as either cpm or a stimulation index (SI; ratio of cpm for stimulated cells to the cpm for unstimulated cells) . For the whole blood assay, the F line had generally lower SI values in the responses to Con A than the RBC2 line, with differences being significant at 0 and 2 d postinjection (P < or = 0.01) and at 14 d postinjection (P < or = 0.05) . Genetic selection for increased BW might have affected the lymphoblastogenic potential of Line F that could affect disease resistance.

Lab Anim Sci, 1999 Oct, 49(5), 551 - 9
Characterization of rabbit Pasteurella multocida isolates by use of whole-cell, outer-membrane, and polymerase chain reaction typing; Dabo SM et al.; PURPOSE: To characterize Pasteurella multocida isolates from laboratory rabbits using serotyping, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins (WCPs) and outer-membrane proteins (OMPs), and polymerase chain reaction (PCR) fingerprinting . METHODS: Fifty isolates were obtained from five sources: ATCC (1), Oklahoma (4), Michigan (9), Minnesota (7), and Texas (29) . The PCR fingerprinting was conducted using two minisatellite probes for M13 and a modified M13 core sequence and two microsatellite probes--(GTG)5 and (GACA)4 . RESULTS: Forty-five isolates were serogroup A, and five were serogroup D . Ten WCP patterns (W1-W10) with one variation (W1a) and 10 OMP (OM1-OM10) patterns were found . Primers M13 phage, modified M13 phage, (GTG)5, and (GACA)4 generated 7, 9, 5, and 9 fingerprint types, respectively . Combination of WCP, OMP, and PCR fingerprint results yielded 39 groups with a discrimination index of 0.98 . The PCR fingerprint results generally indicated clonal association among isolates within geographic locations except for the isolates from Texas, which varied markedly in PCR fingerprint types . CONCLUSION: Single primer PCR fingerprinting provided a simple and rapid means of typing P . multocida isolates from laboratory rabbits . Combinations of conventional and molecular typing enhanced differentiation among P . multocida isolated from rabbits with pasteurellosis.

APMIS, 1999 Oct, 107(10), 913 - 20
Typing of Pasteurella multocida from haemorrhagic septicaemia in Danish fallow deer (Dama dama); Aalbaek B et al.; Isolates of Pasteurella multocida ssp . multocida (n = 31) from a Danish population of fallow deer which succumbed to haemorrhagic septicaemia during 1992 1993 and isolates from the palatine tonsils of apparently healthy fallow deer from the same area (n=6) were typed and compared with P . multocida from other sources . Plasmids were net observed in the fallow deer strains and one unique pattern was observed by ribotyping using HindIII and by pulsed-field gel electrophoresis using SanlI as restriction endonuclease . All Danish fallow deer isolates belonged to serotype B:3,4 . On restriction endonuclease analysis using HhaI as restriction endonuclease, all had a profile identical to that of a fallow deer isolate from the United Kingdom: profile 0033 of Wilson et al . On restriction endonuclease analysis using HpaII as restriction endonuclease, the Danish fallow deer isolates had a unique profile, designated 0062, which differed slightly from that of a fallow deer isolate from the United Kingdom . P . multocida from other animal species were genotypically different from the fallow deer isolates . It is concluded that a specific clone of P . multocida was responsible for the outbreak of haemorrhagic septicaemia among Danish fallow deer . A carrier rate of 27% was demonstrated among apparently normal animals from the same population.

FEMS Microbiol Lett, 1999 Nov 1, 180(1), 15 - 20
Reduced pH causes structural changes in the potent mitogenic toxin of Pasteurella multocida; Smyth MG et al.; Pasteurella multocida toxin is a potent mitogen that is believed to act intracellularly . On transverse urea gradient gels at pH 8.0 the toxin displayed one major unfolding transition at 4 M urea . However, at pH 6.1 the unfolding transition took place at 3.5 M urea . Circular dichroism spectra also indicated that a structural change took place at acidic pH . In addition it was found that the toxin that had been denatured in 8 M urea refolded in solution with a high recovery of biological activity . These findings are discussed in terms of the likely domain structure of the P . multocida toxin.

Microb Pathog, 1999 Nov, 27(5), 311 - 27
Identification of in vivo induced genes in Actinobacillus pleuropneumoniae; Fuller TE et al.; We have developed an in vivo expression technology (IVET) system to identify Actinobacillus pleuropneumoniae gene promoters that are specifically induced in vivo during infection . This system is based upon an avirulent riboflavin-requiring A . pleuropneumoniae mutant and a promoter-trap vector (pTF86) that contains, in sequence, the T4 terminator, a unique Bam HI site, a promoterless copy of the V . harveyi luxAB genes, and a promoterless copy of the B . subtilis ribBAH genes in the E . coli - A . pleuropneumoniae shuttle vector pGZRS19 . Sau 3A fragments of A . pleuropneumoniae genomic DNA were cloned into the Bam HI site in pTF86 and transformed into the A . pleuropneumoniae Rib- mutant . Pigs were infected with pools of 300-600 transformants by endobronchial inoculation and surviving bacteria were isolated from the pigs' lungs at 12-16 h post-infection . Infection strongly selected for transformants containing cloned promoters which drove expression of the vector ribBAH genes and allowed survival of the Rib- mutant in vivo . Strains that survived in vivo, but which minimally expressed luciferase activity in vitro, should contain cloned promoters that are specifically induced in vivo . Ten clones, designated iviA-J, were isolated which contain promoters that are induced in vivo during infection . These ivi clones were shown to be induced in the animal by luminescence of infected tissue and by direct assay of bacteria recovered from bronchoalveolar lavage . Four of these clones were putatively identified by amino acid sequence similarity as ilvI, the ilvDA operon, the secE-nusG operon, and the mrp gene . This is the first report of an IVET system for use in the family Pasteurellaceae, as well as the first report of an IVET system utilizing an infection model of pneumonia in the natural host .

J Bacteriol, 1999 Nov, 181(21), 6747 - 55
Bacterial phylogenetic clusters revealed by genome structure; Liu SL et al.; Current bacterial taxonomy is mostly based on phenotypic criteria, which may yield misleading interpretations in classification and identification . As a result, bacteria not closely related may be grouped together as a genus or species . For pathogenic bacteria, incorrect classification or misidentification could be disastrous . There is therefore an urgent need for appropriate methodologies to classify bacteria according to phylogeny and corresponding new approaches that permit their rapid and accurate identification . For this purpose, we have devised a strategy enabling us to resolve phylogenetic clusters of bacteria by comparing their genome structures . These structures were revealed by cleaving genomic DNA with the endonuclease I-CeuI, which cuts within the 23S ribosomal DNA (rDNA) sequences, and by mapping the resulting large DNA fragments with pulsed-field gel electrophoresis . We tested this experimental system on two representative bacterial genera: Salmonella and Pasteurella . Among Salmonella spp., I-CeuI mapping revealed virtually indistinguishable genome structures, demonstrating a high degree of structural conservation . Consistent with this, 16S rDNA sequences are also highly conserved among the Salmonella spp . In marked contrast, the Pasteurella strains have very different genome structures among and even within individual species . The divergence of Pasteurella was also reflected in 16S rDNA sequences and far exceeded that seen between Escherichia and Salmonella . Based on this diversity, the Pasteurella haemolytica strains we analyzed could be divided into 14 phylogenetic groups and the Pasteurella multocida strains could be divided into 9 groups . If criteria for defining bacterial species or genera similar to those used for Salmonella and Escherichia coli were applied, the striking phylogenetic diversity would allow bacteria in the currently recognized species of P . multocida and P . haemolytica to be divided into different species, genera, or even higher ranks . On the other hand, strains of Pasteurella ureae and Pasteurella pneumotropica are very similar to those of P . multocida in both genome structure and 16S rDNA sequence and should be regarded as strains within this species . We conclude that large-scale genome structure can be a sensitive indicator of phylogenetic relationships and that, therefore, I-CeuI-based genomic mapping is an efficient tool for probing the phylogenetic status of bacteria.

Poult Sci, 1999 Oct, 78(10), 1377 - 9
Variation in resistance to Pasteurella multocida among turkey lines; Nestor KE et al.; Previous research has shown that a line (F) of turkeys selected long-term for increased 16-wk body weight was more susceptible to challenge with washed Pasteurella multocida than a randombred control line (RBC2), the base population of F . A previous study also indicated that the mortality of the F line following challenge with P . multocida was similar to that of sire lines from two of the three major primary breeders . The purpose of the present study was to compare the resistance of the sire line from the third major primary turkey breeder (C) not previously studied with that of the F and RBC2 lines to determine whether there is variation in resistance among the sire lines from three major primary breeders . The sire lines from all three primary breeders were used in the production of commercial turkeys . Body weights of the F line were greater than those of the C line at the time of challenge with P . multocida . Both the C and F lines were heavier than the RBC2 line . The birds were challenged at 6 wk of age with a field isolate of washed P . multocida (1.2 x 10(7) organism per bird of capsular serogroup A and somatic serotype 3,4) . Mortality was recorded daily for 14 d . Mortality following challenge with P . multocida was higher in the F line than in the C line, and both large-bodied lines had higher mortality than the RBC2 line . Based on the present results and those published in the literature, there may be variation in resistance among commercial sire lines from the three major primary breeders.

Lancet, 1999 Oct 9, 354(9186), 1267 - 8
Beware of dogs licking ears; Godey B et al.; A patient with right-sided chronic purulent otorrhoea developed meningitis due to Pasteurella multocida transmitted by a dog that frequently licked his ear . We suggest that patients with a perforated tympanic membrane should avoid being licked on their ears by animals.

Poult Sci, 1999 Sep, 78(9), 1268 - 74
Effect of feed withdrawal or challenge with Pasteurella multocida on growth, blood metabolites, circulating growth hormone, and insulin-like growth factor-I concentrations in eight-week-old turkeys; Anthony NB et al.; The daily effects of feed withdrawal or a bacterial disease (Pasteurella multocida; PM) challenge was studied in a slow-growing line of turkeys . The following groups (n = 6 birds/group) were sampled for up to 13 d: untreated control (CON), 4-d feed withdrawal followed by refeeding (FAST), a group that succumbed within the first 2 to 3 d after PM challenge (E-DEAD), a group that succumbed 8 to 9 d after PM challenge (L-DEAD), a group that survived the PM challenge (SUR), and a group treated with both PM challenge and 4-d feed withdrawal followed by refeeding (FAST/CHAL) . Daily feed intake and BW gains were markedly reduced in the E-DEAD and L-DEAD groups immediately and 3 d after PM challenge, respectively . Feed intake and BW gain between CON and SUR groups of turkeys were not different throughout the trial . The turkeys in the FAST group followed the expected feed withdrawal and refeeding patterns for feed intake and BW loss or gain . The FAST/CHAL turkeys consumed the minimal amount of feed to maintain BW after refeeding . Plasma uric acid sharply increased 1 d prior to death in both E-DEAD and L-DEAD groups of turkeys . Plasma uric acid also increased each consecutive day during fasting in the FAST and FAST/CHAL groups of turkeys . Plasma growth hormone was measured in only the CON and FAST groups and increased from about 40 to 85 ng/mL in the FAST group during fasting but returned to control levels within 1 d of refeeding . Circulating plasma insulin-like growth factor-I (IGF-I) decreased from about 17 to 5 ng/mL in the PM-challenged (E-DEAD, L-DEAD, and FAST/CHAL groups) and FAST groups . The concentration of IGF-I returned to prefeed withdrawal levels within 3 d of refeeding the FAST group of turkeys . It was concluded that 1) turkey poults that were not susceptible to the PM challenge generally maintained physiological functions at control bird levels, 2) susceptible turkey poults generally exhibited depressed feed intake and BW gains, and 3) poults challenged with both feed withdrawal and PM treatment responded differently than poults challenged with either feed withdrawal or challenge with PM . The depletion of energy intake and mobilization of energy stores in susceptible poults might have contributed to the rate at which PM caused the poults to die.

Poult Sci, 1999 Sep, 78(9), 1263 - 7
Influence of body weight restriction in a body-weight-selected line of turkeys on response to challenge with Pasteurella multocida; Nestor KE et al.; Previous research has shown that a line (F) of turkeys selected long-term for increased 16-wk BW was more susceptible to challenge with washed Pasteurella multocida (PM) than a randombred control line (RBC2), the base population of the F line . Published research indicated that the mortality of the F line following challenge with PM was similar to that of two commercial sire lines . The purpose of the present study was to determine the influence of reducing BW of the F line to that of the RBC2 line by nutrient restriction on resistance to PM . Four challenge trials were conducted over a 2-yr period . The BW of a group of F line birds was restricted to that of the RBC2 line by limiting access to feed from 1 to 6 wk of age . The F line restricted birds and full-fed RBC2 and F line birds were challenged with a field isolate of washed PM (1.2x10(7) organisms/bird of capsular serogroup A and somatic serotype 3, 4) at 6 wk of age . Birds were checked twice daily for 14 d . Resistance to PM was measured by days to death of those that died and percentage mortality . The BW of the restricted group of the F line did not differ from full-fed RBC2 birds for males or females . In males, the restricted F line birds had similar mortality (48.0%) to the full-fed RBC2 line birds (44.3%), and the mortalities in both groups were significantly lower than that observed for the full-fed F line birds (81.3%) following challenge with PM . The mortality following challenge in females did not differ significantly among groups, even though mortality of the full-fed F line birds (64.1%) and restricted F line birds (63.3%) was more than 9% higher than that (54.2%) observed for the full-fed RBC2 line birds . Days to death was not a sensitive indicator of resistance to PM, as no differences among the three groups of birds were observed for either sex.

Res Vet Sci, 1999 Oct, 67(2), 163 - 70
Ultrastructural pathology of the upper respiratory tract of rabbits experimentally infected with Pasteurella multocida A:3; Al-Haddawi MH et al.; Twenty-four 8 to 9 week-old Pasteurella multocida -free rabbits were divided into three equal groups, the first group was pretreated with hydrocortisone and inoculated intranasally with pasteurella multocida serotype A:3 . The second group was inoculated intranasally with P . multocida without hydrocortisone treatment . The third group was inoculated with phosphate buffered saline only and used as a control group . Pasteurella multocida was isolated from the nasal cavity of all infected rabbits in group 1 and 2 and from the trachea of seven rabbits in group 1 and five rabbits in group 2 . This study was conducted to observe the ultrastructural changes of the upper respiratory tract of hydrocortisone treated and non-treated rabbits infected with P . multocida serotype A:3 . The ultrastructural changes detected in infected rabbits were ciliary destruction and deciliation of the ciliated epithelial cells, cellular swelling, goblet cell hyperplasia and endothelial cell damage . Pasteurella multocida was observed attached to the degenerated cilia, microvilli and mucus . Pasteurella multocida infection was associated with inflammatory responses, which may have caused tissue damage . It is possible that hydrocortisone modulates the severity of infection as an immune suppressor and an inhibitor of goblet cell secretion .

Microb Pathog, 1999 Oct, 27(4), 197 - 206
Protective capacity of the Pasteurella haemolytica transferrin-binding proteins TbpA and TbpB in cattle; Potter AA et al.; The transferrin-binding proteins TbpA and TbpB from Pasteurella haemolytica biotype A serotype 1 were tested for their ability to confer protection against experimental P . haemolytica infection when administered to calves in vaccine formulations containing one or both antigens . Vaccine groups included TbpB (single immunization), TbpB (two immunizations), TbpA, TbpA+TbpB and a placebo . All animals that received TbpB had measurable antibody titres against the antigen at the time of challenge, while those that received TbpA did not show an antibody response . The TbpA+TbpB group showed the best protection against experimental challenge . Protection correlated with anti-TbpB antibody levels . The enhanced protection in the TbpA+TbpB group suggests TbpA contributed to protection through the induction of a non-antibody-mediated immune response . Sera from the TbpB-immunized animals was cross-reactive with TbpBs from other P . haemolytica serotypes .

Pediatr Nephrol, 1999 Oct, 13(8), 646 - 8
Capnocytophaga canimorsus peritonitis in a pediatric peritoneal dialysis patient; Chadha V et al.; Capnocytophaga canimorsus, a bacterium rarely encountered by clinicians, was responsible for the development of peritonitis in an 18-year-old white male on automated peritoneal dialysis following the puncture of his dialysis tubing by a domestic cat . Although more than 100 cases of septicemia caused by C . canimorsus have been reported, this is the first report of the organism causing peritonitis in a patient receiving peritoneal dialysis . Of interest, the patient had a prior episode of peritonitis secondary to Pasteurella multocida, also following transmission from the same cat.

Avian Dis, 1999 Jul-Sep, 43(3), 549 - 52
Survey of pathogens and blood parasites in free-living passerines; Morishita TY et al.; To determine the disease prevalence of free-living passerines, 1709 passerines were sampled from 38 different field sites in Ohio . Choanal and cloacal swabs were collected from each bird and cultured for the presence of Pasteurella multocida, Salmonella spp., and Escherichia coli by standard microbiologic techniques . In addition, the serum from each bird was analyzed for the presence of antibodies to Mycoplasma gallisepticum, Mycoplasma synoviae, Newcastle disease virus, and avian influenza virus . A blood smear was also made to examine for the presence of blood parasites . Results indicated that the isolation of E . coli varied with bird species, with the European starling having a higher (21.4%) isolation of E . coli . Salmonella spp . were also isolated from these free-living passerines . Pasteurella multocida was not isolated from any of the sampled passerines . These birds did not have antibodies to M . gallisepticum, M . synoviae, Newcastle disease virus, or avian influenza virus . Blood parasites were not detected in any of the birds sampled.

Vet Pathol, 1999 Sep, 36(5), 437 - 44
In situ expression of intercellular adhesion molecule-1 (ICAM-1) mRNA in calves with acute Pasteurella haemolytica pneumonia; Radi ZA et al.; The in situ expression of intercellular adhesion molecule-1 (ICAM-1) mRNA in normal and pneumonic lung tissues of Holstein calves with bovine leukocyte adhesion deficiency (BLAD) was compared with that of age-matched non-BLAD Holstein calves by in situ hybridization . Twenty-four Holstein calves (both BLAD and non-BLAD) were randomly assigned to one of two experimental groups and inoculated intrabronchially with Pasteurella haemolytica or pyrogen-free saline . Lung tissues were collected and fixed in 10% neutral formalin at 2 or 4 hours postinoculation (PI) . The expression and distribution of ICAM-1 mRNA in the different cell types of the lung tissue was detected by in situ hybridization with a 307-base-pair bovine ICAM-1 riboprobe . In lungs of both non-BLAD and BLAD saline-inoculated calves, ICAM-1 expression was present in epithelial cells but occurred in <30% of cells in bronchi, bronchioles, and alveoli . ICAM-1 expression in vascular endothelial cells was present in <30% of cells in pulmonary arteries and veins . The expression of ICAM-1 was significantly greater (>60% of cells) in bronchiolar and alveolar epithelial cells and pulmonary endothelial cells of arteries and veins in both BLAD and non-BLAD calves inoculated with P . haemolytica . Bronchiolar epithelium had the highest intensity of mRNA expression and highest percentage of cells that were stained, whereas bronchial epithelium had the lowest intensity and percentage of cells stained . Most alveolar macrophages and neutrophils in infected lungs also expressed ICAM-1 . ICAM-1 expression was generally increased in infected BLAD calves at 2 hours PI as compared with non-BLAD calves but not at 4 hours PI . The increased expression of ICAM-1 during acute P . haemolytica pneumonia in calves suggests that ICAM-1 is upregulated and may play a role in leukocyte infiltration . The extent of ICAM-1 expression in P . haemolytica-inoculated calves with BLAD was initially enhanced but otherwise similar to that in non-BLAD calves.

Vet Pathol, 1999 Sep, 36(5), 397 - 405
Expression of inducible nitric oxide synthase in spontaneous bovine bronchopneumonia; Fligger JM et al.; The expression of inducible nitric oxide synthase (iNOS), major histocompatibility class II molecules (MHC-II), CD68, and the calcium-binding proteins S100A8 and S100A9 (also called MRP8 and MRP14, respectively) was assessed in lung tissues from cattle that succumbed to pneumonia . Expression patterns of these markers were related to the types of lung lesion . iNOS expression was only observed in lungs infected with Arcanobacterium pyogenes or Pasteurella haemolytica but not in lungs from cattle with subacute chronic interstitial pneumonia and acute interstitial pneumonia due to Escherichia coli infection . High levels of iNOS were expressed by cells (probably leukocytes) surrounding necrotic foci . Occasionally, iNOS was expressed by intraalveolar macrophages in viable parenchyma, by leukocytes within the airways, and by some chondrocytes in the supporting cartilage of bronchi . Cells expressing MHC-II were distributed relatively evenly throughout areas of inflammation and did not display any clear association with necrotic foci . Cell types expressing MHC-II included type II alveolar epithelial cells, spindle-shaped cells of the interstitium, cells in bronchus-associated lymphoid tissue, and leukocytes in lymph and blood vessels but largely excluded iNOS-positive cells . Likewise, CD68-positive cells were rarely positive for iNOS and were not confined to the areas surrounding necrotic tissue . As with MHC-II and CD68, there was little if any coexpression of iNOS and either of the S100 proteins tested . Thus, in cattle with necrotizing bronchopneumonia, iNOS-expressing cells were largely restricted to the cellular zone surrounding necrotic areas.

J Zoo Wildl Med, 1999 Jun, 30(2), 285 - 92
Hemorrhagic septicemia in fallow deer (Dama dama) caused by Pasteurella multocida multocida; Eriksen L et al.; Four outbreaks of hemorrhagic septicemia caused by Pasteurella multocida multocida occurred in a population of 1,800 fallow deer (Dama dama) during 1992-1996 . A total of 340 fallow deer were submitted for postmortem examination . Pasteurellosis was diagnosed in 273 of 312 deer suspected of having septicemia . Pasteurella multocida was isolated from 257 animals, and the diagnosis was based on typical pathologic changes alone in the other 16 animals . Pasteurella multocida was isolated in pure culture from 219 of 248 samples of cerebrospinal fluid . Eighteen animals were observed moribund with severe depression, foamy nasal discharge, and respiratory distress, and 257 were found dead . Major clinical signs and pathologic changes included extensive swelling of the head and the neck and peracute or acute septic pneumonia, petechial and ecchymotic hemorrhages on serous membranes, and severely hemorrhagic adrenal glands and abomasum . Rhinitis and necrotic pharyngeal mucosae were common . Histologically, the most advanced lesions were in the nasal mucosa and pharynx . The swelling of the head and the neck arose from a diffuse cellulitis in the subcutaneous and intermuscular tissues . The earliest lesions in the lungs included large numbers of bacteria in the pulmonary capillaries, but various degrees of fibrinous exudation to the alveoli and infiltration with heterophils usually were observed.

FEMS Microbiol Lett, 1999 Oct 1, 179(1), 161 - 7
The leukotoxin of Pasteurella haemolytica binds to beta(2) integrins on bovine leukocytes; Ambagala TC et al.; The putative receptor proteins of Pasteurella haemolytica leukotoxin were isolated from bovine polymorphonuclear neutrophil lysate by affinity chromatography on a leukotoxin-specific monoclonal antibody column to which the leukotoxin was pre-bound . SDS-PAGE of the purified proteins showed four bands at 180 kDa, 170 kDa, 150 kDa and 95 kDa, in addition to the expected 102-kDa leukotoxin band and a series of bands with molecular masses lower than 102 kDa representing the disintegrated leukotoxin . N-terminal amino acid sequencing of the 170-kDa band showed homology with human and murine CD11b . The purified proteins reacted specifically with monoclonal antibodies specific for CD11a, CD11b, CD11c (the alpha chains of beta(2) integrins), and CD18 (the beta chain of beta(2) integrins) . Pre-incubation of polymorphonuclear neutrophils with a monoclonal antibody specific for CD18 reduced the cytotoxicity of the leukotoxin to the cells . These results indicate that the leukotoxin binds to the beta(2) integrins on bovine leukocytes, very likely via CD18.

J Wildl Dis, 1999 Jul, 35(3), 440 - 9
Antibodies against Pasteurella multocida in snow geese in the western Arctic; Samuel MD et al.; To determine if lesser snow geese (Chen caerulescens caerulescens) are a potential reservoir for the Pasteurella multocida bacterium that causes avian cholera, serum samples and/or pharyngeal swabs were collected from > 3,400 adult geese breeding on Wrangel Island (Russia) and Banks Island (Canada) during 1993-1996 . Pharyngeal swab sampling rarely (> 0.1%) detected birds that were exposed to P . multocida in these populations . Geese with serum antibody levels indicating recent infection with P . multocida were found at both breeding colonies . Prevalence of seropositive birds was 3.5% at Wrangel Island, an area that has no recorded history of avian cholera epizootics . Prevalence of seropositive birds was 2.8% at Banks Island in 1994, but increased to 8.2% during 1995 and 1996 when an estimated 40,000-60,000 snow geese were infected . Approximately 50% of the infected birds died during the epizootic and a portion of the surviving birds may have become carriers of the disease . This pattern of prevalence indicated that enzootic levels of infection with P . multocida occurred at both breeding colonies . When no avian cholera epizootics occurred (Wrangel Island, Banks Island in 1994), female snow geese (4.7%) had higher antibody prevalence than males (2.0%).

J Biol Chem, 1999 Sep 10, 274(37), 26557 - 62
Molecular directionality of polysaccharide polymerization by the Pasteurella multocida hyaluronan synthase; DeAngelis PL; Hyaluronan (HA), a long linear polymer composed of alternating glucuronic acid and N-acetylglucosamine residues, is an essential polysaccharide in vertebrates and a putative virulence factor in certain microbes . All known HA synthases utilize UDP-sugar precursors . Previous reports describing the HA synthase enzymes from Streptococcus bacteria and mammals, however, did not agree on the molecular directionality of polymer elongation . We show here that a HA synthase, PmHAS, from Gram-negative P . multocida bacteria polymerizes the HA chain by the addition of sugar units to the nonreducing terminus . Recombinant PmHAS will elongate exogenous HA oligosaccharide acceptors to form long polymers in vitro; thus far no other HA synthase has displayed this capability . The directionality of synthesis was established definitively by testing the ability of PmHAS to elongate defined oligosaccharide derivatives . Analysis of the initial stages of synthesis demonstrated that PmHAS added single monosaccharide units sequentially . Apparently the fidelity of the individual sugar transfer reactions is sufficient to generate the authentic repeating structure of HA . Therefore, simultaneous addition of disaccharide block units is not required as hypothesized in some recent models of polysaccharide biosynthesis . PmHAS appears distinct from other known HA synthases based on differences in sequence, topology in the membrane, and putative reaction mechanism.

Berl Munch Tierarztl Wochenschr, 1999 Jun-Jul, 112(6-7), 254 - 9
{Breath condensate--a medium obtained by a noninvasive method for the detection of inflammation mediators of the lung}; Reinhold P et al.; Collection of exhaled condensate (freezing of expired air under conditions of spontaneous breathing) is a non-invasive method permitting the collection of material originating from the lung and the lower respiratory tract so that it can be used for diagnostic examinations . In order to be able to evaluate the diagnostic evidence of exhaled condensate samples in cases of respiratory disease of the calf, leukotriene B4 (LTB4) in bovine exhaled condensate was determined . The influence of the breathing pattern and body temperature on the quantity of condensate to be collected was tested in a total of 49 exhaled condensate samples . It became obvious that the exhaled condensate quantity obtained per time unit is dependent on the ventilation volume per time unit (minute volume) . In exhaled condensate samples from 35 clinically healthy calves, LTB4 concentrations of less than 250 pg/mL exhaled condensate were detected . A total of 14 exhaled condensate samples from 7 calves was analyzed before and after experimental respiratory infection with Pasteurella multocida D . In parallel to the analysis of LTB4 in exhaled condensate, the lung function of the calves was examined by means of impulse oscilloresistometry . The increase of LTB4 in the exhaled condensate post infection correlated significantly (p < or = 0.05) with decreases of respiratory reactance . The determination of LTB4 concentrations in exhaled condensate seems to be suitable, in principle, for the detection of inflammations in the respiratory system of the calf . Further studies are needed for the evaluation of the diagnostic validity of the method.

Antimicrob Agents Chemother, 1999 Sep, 43(9), 2138 - 43
Effects of enrofloxacin on porcine phagocytic function; Schoevers EJ et al.; The interaction between enrofloxacin and porcine phagocytes was studied with clinically relevant concentrations of enrofloxacin . Enrofloxacin accumulated in phagocytes, with cellular concentration/extracellular concentration ratios of 9 for polymorphonuclear leukocytes (PMNs) and 5 for alveolar macrophages (AMs) . Cells with accumulated enrofloxacin brought into enrofloxacin-free medium released approximately 80% (AMs) to 90% (PMNs) of their enrofloxacin within the first 10 min, after which no further release was seen . Enrofloxacin affected neither the viability of PMNs and AMs nor the chemotaxis of PMNs at concentrations ranging from 0 to 10 microg/ml . Enrofloxacin (0.5 microg/ml) did not alter the capability of PMNs and AMs to phagocytize fluorescent microparticles or Actinobacillus pleuropneumoniae, Pasteurella multocida, and Staphylococcus aureus . Significant differences in intracellular killing were seen with enrofloxacin at 5x the MIC compared with that for controls not treated with enrofloxacin . PMNs killed all S . aureus isolates in 3 h with or without enrofloxacin . Intracellular S . aureus isolates in AMs were less susceptible than extracellular S . aureus isolates to the bactericidal effect of enrofloxacin . P . multocida was not phagocytosed by PMNs . AMs did not kill P . multocida, and similar intra- and extracellular reductions of P . multocida isolates by enrofloxacin were found . Intraphagocytic killing of A . pleuropneumoniae was significantly enhanced by enrofloxacin at 5x the MIC in both PMNs and AMs . AMs are very susceptible to the A . pleuropneumoniae cytotoxin . This suggests that in serologically naive pigs the enhancing effect of enrofloxacin on the bactericidal action of PMNs may have clinical relevance.

Eur J Biochem, 1999 Aug, 263(3), 695 - 701
31P and 13C nuclear magnetic resonance studies of metabolic pathways in Pasteurella multocida characterization of a new mannitol-producing metabolic pathway; Rager MN et al.; Glucose metabolism of Pasteurella multocida was examined in resting cells in vivo using 13C NMR spectroscopy, in cell-free extracts in vitro using 31P NMR spectroscopy and using enzyme assays . The NMR data indicate that glucose is converted by the Embden-Meyerhof and pentose phosphate pathways . The P . multocida fructose 6-phosphate phosphotransferase activity (the key enzyme of the Embden-Meyerhof pathway) was similar to that of Escherichia coli . Nevertheless, and in contrast to that of E . coli, its activity was inhibited by alpha glycerophosphate . This inhibition is consistent with the very low fructose 6-phosphate phosphotransferase activity found in cell-free extracts of P . multocida using a spectrophotometric method . The dominant end products of glucose metabolism were mannitol, acetate and succinate . Under anaerobic conditions, P . multocida was able to constitutively produce mannitol from glucose, mannose, fructose, sucrose, glucose 6-phosphate and fructose 6-phosphate . We propose a new metabolic pathway in P . multocida where fructose 6-phosphate is reduced to mannitol 1-phosphate by fructose 6-phosphate reductase . Mannitol 1-phosphate produced is then converted to mannitol by mannitol 1-phosphatase.

Int J Antimicrob Agents, 1999 Aug, 12(3), 229 - 37
Postantibiotic and physiological effects of tilmicosin, tylosin, and apramycin at subminimal and suprainhibitory concentrations on some swine and bovine respiratory tract pathogens; Diarra MS et al.; The antimicrobial activity of tilmicosin, tylosin, and apramycin on some important gram-negative swine and bovine pathogens namely, Pasteurella multocida, Pasteurella haemolytica, Bordetella bronchiseptica, and Actinobacillus pleuropneumoniae were studied in vitro . The effect of minimal inhibitory concentrations (MICs) and sub-MICs (1/4, 1/2 MIC) on bacterial growth was evaluated . The presence of tilmicosin, tylosin and apramycin in the medium decreased the rate of growth of the bacterial strains tested using drug concentrations as low as 1/4 MIC . The postantibiotic effect (PAE) which is the suppression of optimal bacterial growth that persists after a short exposure (2 h) of microorganisms to an antibiotic was studied by exposure of bacteria to drugs at 1/4, 1/2, 1, 4 and 8 times MIC . The duration of PAEs increased with rising concentration for all drugs tested but at concentrations below the MIC, tilmicosin showed more significant PAEs than tylosin or apramycin against P . multocida and A . pleuropneumoniae . Tilmicosin and tylosin caused PAEs of up to 8 h when used at 8 times the MIC, while apramycin caused PAEs of up to 5 h when used at this concentration . Sub-MICs of either tilmicosin, tylosin, or apramycin had no effect on P . multocida dermonecrotic toxin production . However sub-MICs of tylosin, or apramycin significantly reduced the haemolytic activity of A . pleuropneumoniae and affected the capsular material production of this isolate and of one isolate of P . multocida (type A) . The in vitro effect of tilmicosin, tylosin, and apramycin (even when used at sub-MIC levels) on growth, production of capsular material, and haemolytic activity might impair the virulence of some of the microorganisms studied . In addition to the effects of these drugs on some putative virulence factors, we suggest that the strong PAEs caused by tilmicosin, tylosin, and apramycin may also contribute to the in vivo efficacy of these drugs.

Infect Immun, 1999 Sep, 67(9), 4968 - 73
Molecular cloning of the Pasteurella haemolytica pomA gene and identification of bovine antibodies against PomA surface domains; Zeng H et al.; The gene (pomA) encoding PomA, an OmpA-like major outer membrane protein of the bovine respiratory pathogen Pasteurella haemolytica, was cloned, and its nucleotide sequence was determined . The deduced amino acid sequence of PomA has significant identity with the sequences of other OmpA family proteins . Absorption of three different bovine immune sera with whole P . haemolytica cells resulted in a reduction of bovine immunoglobulin G reactivity with recombinant PomA in Western immunoblots, suggesting the presence of antibodies against PomA surface domains.

Microb Pathog, 1999 Sep, 27(3), 179 - 85
Use of TUNEL staining to detect apoptotic cells in the lungs of cattle experimentally infected with Pasteurella haemolytica; Leite F et al.; Lung sections taken from calves with experimental Pasteurella haemolytica respiratory infection exhibited increased numbers of TUNEL positive cells with time after challenge . This finding suggests that P . haemolytica, or toxins and other components released by the organism, induces apoptosis in bovine leukocytes in vivo . By so doing this might impair host defense and contribute in part to the severe pneumonia that characterizes bovine pasteurellosis .

Antimicrob Agents Chemother, 1999 Aug, 43(8), 1988 - 92
Pharmacokinetics of enrofloxacin and danofloxacin in plasma, inflammatory exudate, and bronchial secretions of calves following subcutaneous administration; McKellar Q et al.; Enrofloxacin (2.5 mg/kg of body weight) and danofloxacin (1.25 mg/kg) were administered subcutaneously to ruminating calves (n = 8) fitted with subcutaneous tissue cages . Concentrations of enrofloxacin, its metabolite ciprofloxacin, and danofloxacin in blood (plasma), tissue cage exudate (following intracaveal injection of 0.3 ml of 1% {vol/wt} carrageenan), and bronchial secretions were measured by high-performance liquid chromatography (HPLC) and microbiological assay (enrofloxacin plus ciprofloxacin and danofloxacin) . Mean maximum concentrations (C(max)) +/- standard deviations of enrofloxacin (0.24 +/- 0.08 microg/ml), ciprofloxacin (0.11 +/- 0.03 {total, 0.34 +/- 0.10} microg/ml), and danofloxacin (0.23 +/- 0.05 microg/ml) were detected in the plasma of calves by HPLC . The C(max) were 0.49 +/- 0.17 microg/ml (enrofloxacin equivalents) and 0.24 +/- 0.03 microg/ml (danofloxacin) when they were measured by microbiological assay . Mean C(max) in exudate (HPLC) were 0.18 +/- 0.07 microg/ml (enrofloxacin), 0.10 +/- 0.04 microg/ml (ciprofloxacin), 0.27 +/- 0.09 microg/ml (enrofloxacin plus ciprofloxacin), and 0.19 +/- 0.05 microg/ml (danofloxacin), and concentrations in exudate exceeded those in plasma from 8 h (enrofloxacin and ciprofloxacin) or 6 h (danofloxacin) after drug administration . The C(max) were 0.34 +/- 0.09 microg/ml (enrofloxacin equivalents) and 0.22 +/- 0.04 microg/ml (danofloxacin) in exudate when they were measured by the microbiological assay . The maximum mean concentration achieved in bronchial secretions (HPLC) were 0.07 +/- 0.04 microg/ml (enrofloxacin), 0.04 +/- 0.07 microg/ml (ciprofloxacin), 0.10 +/- 0 . 05 microg/ml (enrofloxacin plus ciprofloxacin), and 0.12 +/- 0.09 microg/ml (danofloxacin) . The maximum mean concentration in bronchial secretions from a limited number of animals from which samples were available for microbiological assay were 0.27 +/- 0.11 microg/ml (n = 4 {enrofloxacin equivalents}) and 0.14 +/- 0.02 microg/ml (n = 3 {danofloxacin}) . With predictive models of efficacy (C(max)/MIC and area under the concentration-time curve/MIC ratios in plasma) for Pasteurella multocida (MIC of enrofloxacin, 0.06 microg/ml {24}; MIC of danofloxacin, 0.06 microg/ml {6}), enrofloxacin produced scores of 8.17 and 52.00, respectively, compared to those of danofloxacin, which were 4.02 and 23.05, respectively . With the dosing rates recommended in some markets by manufacturers, enrofloxacin and danofloxacin achieved concentrations above the MICs for important pathogenic organisms in plasma, tissue cage exudate, and bronchial secretion . Since fluoroquinolones display concentration-dependent activities, C(max)/MIC ratios may be critical to efficacy . In the United States enrofloxacin is currently the only fluoroquinolone licensed for food animals and dosages for acute respiratory disease are 2.5 to 5 mg/kg for 3 days or 7.5 to 12 . 5 mg/kg once . The higher dosages on a single occasion are likely to confer C(max)/MIC ratios that are associated with greater clinical efficacy.

Vet Q, 1999 Jun, 21(3), 99 - 104
Sensitivity testing of veterinary pathogens with a semi-automatic image analysis system compared with tablet diffusion and agar dilution tests; Mevius DJ et al.; Recently a commercial computer-controlled image analysis system (IAS) was introduced to measure automatically the diameters of inhibition zones in the agar diffusion test . However, there is little information on the precision of this method . In the present study clinical isolates of Salmonella spp . (N = 104), Escherichia coli (N = 100), Pasteurella spp . (N = 99), Actinobacillus pleuropneumoniae (N = 85), porcine streptococci (N = 100), and Staphylococcus aureus (N = 95) were tested in the agar diffusion test, using nineteen different antibiotics in tablets . All inhibition zone diameters were first measured by a laboratory technician and then by the IAS . Although the zone diameters of all bacteria-antibiotic combinations measured by the IAS and those measured by the laboratory technician showed a significant positive correlation, the size of the inhibition zone diameters measured by the technician and the IAS differed significantly in 59% of the combinations . However, these differences were very small and may have no clinical relevance . The IAS was also used to calculate minimum inhibitory concentrations (MIC values) from the zone diameters . In 82% of the bacteria-antibiotic combinations MIC values calculated by the IAS showed a significant positive correlation with MIC values obtained with the reference agar dilution test . However, in 92% of the bacteria-antibiotic combinations, the calculated MIC values differed significantly from the reference values . In some cases these differences were so large that they could be of clinical relevance . The IAS was unable to measure the diameter of inhibition zones of porcine streptococci properly, due to poor contrast . We concluded that when tablets are used as antibiotic carriers the IAS accurately measures the diameter of inhibition zones for bacteria species that give good contrast between the agar and bacterial growth . MIC values determined with the IAS were only indicative of those determined with the reference agar dilution test.

Kansenshogaku Zasshi, 1999 Jun, 73(6), 623 - 5
{Two cases of pasteurellosis accompanied by exudate with semen-like odor from the wound}; Arashima Y et al.; We encountered two cases of Pasteurella multocida subsp . septica isolation from exudates with seminal fluid-like odor from dog scratch and cat bite . Case 1: A 78-year-old male who had been diagnosed as having diabetes mellitus five years ago was scratched by the claw of a pet dog (Pekinese) on the back of the right hand . Since inflammation ascended to the arm, the patient visited Nihon University Itabashi hospital for a medical examination . Case 2: A 51-year-old female without a specific past history other than hyperlipidemia was bitten by a pet cat at the medical and lateral sides of the left carpus . The patient immediately opened the wound and washed it with tap water, followed by disinfection using a non-iodine disinfectant at home . Two hours later, the patient felt an unpleasant sensation and smelled a seminal fluid-like odor at the wound . The next morning, the entire left arm swelled and pain worsened, then the patient sought medical attention . The patients were treated with antibiotics and the wound completely healed on the 16 days from on set in Case 1 and on the 10 days from onset in Case 2 . From these two cases, Pasteurella multocida subsp . septica was isolated from the exudate, suggesting that when wounds caused by animals smell like seminal fluid, the wound is infected with Pasteurellae . This finding may be an important clue for differentiation in clinical diagnosis.

Infect Immun, 1999 Aug, 67(8), 3768 - 72
Role of phospholipase D in Pasteurella haemolytica leukotoxin-induced increase in phospholipase A(2) activity in bovine neutrophils; Wang Z et al.; The effects of Pasteurella haemolytica leukotoxin (LKT) on the activity of phospholipase D (PLD) and the regulatory interaction between PLD and phospholipase A(2) (PLA(2)) were investigated in assays using isolated bovine neutrophils labeled with tritiated phospholipid substrates of the two enzymes . Exposure of {(3)H}lysophosphatidylcholine-labeled neutrophils to LKT caused concentration- and time-dependent production of phosphatidic acid (PA), the product of PLD . LKT-induced generation of PA was dependent on extracellular calcium . Both production of PA and metabolism of {(3)H}-arachidonate ({(3)H}AA)-labeled phospholipids by PLA(2) were inhibited when ethanol was used to promote the alternative PLD-mediated transphosphatidylation reaction, resulting in the production of phosphatidylethanol rather than PA . The role of PA in regulation of PLA(2) activity was then confirmed by means of an add-back experiment, whereby addition of PA in the presence of ethanol restored PLA(2)-mediated release of radioactivity from neutrophil membranes . Considering the involvement of chemotactic phospholipase products in the pathogenesis of pneumonic pasteurellosis, development and use of anti-inflammatory agents that inhibit LKT-induced activation of PLD and PLA(2) may improve therapeutic management of the disease.

Vet Microbiol, 1999 Jun 15, 67(2), 91 - 7
Bovine CD18 identified as a species specific receptor for Pasteurella haemolytica leukotoxin; Li J et al.; Ligand blotting of Pasteurella haemolytica leukotoxin (LKT) susceptible BL3 bovine lymphoma cell membranes with LKT detected two putative receptors with Mr of 95 and 100 kDa, whereas no LKT binding to membrane proteins was detected for LKT non-susceptible human leukemic cells . Anti-bovine CD18 and CD11a/CD18 mAb recognized 95 and 100kDa bands from BL3 cell membranes . CD18 isolated from BL3 cell membranes bound LKT . Pre-incubation of BL3 cells with anti-bovine CD18 or CD11a/CD18 mAb caused partial inhibition of LKT-induced leukolysis . Therefore, we propose that bovine CD18 acts as a species-specific leukocyte receptor for P . haemolytica LKT.

Am J Vet Res, 1999 Jul, 60(7), 853 - 9
Evaluation of commercially available Escherichia coli J5 bacterin as protection against experimental challenge with Pasteurella multocida in rabbits; Ruble RP et al.; OBJECTIVE: To evaluate the ability of commercially available Escherichia coli J5 bacterin to protect rabbits from experimental challenge with Pasteurella multocida . ANIMALS: 40 P multocida-free New Zealand White rabbits . PROCEDURES: Rabbits were assigned to 1 of 4 groups of 10 rabbits each . Three of the groups were inoculated SC with J5 bacterin at 8 weeks old . Inoculation was repeated 3 and 6 weeks later . The fourth group was not inoculated and served as controls . Groups 1, 2, and 3 were given 10(9), 10(8), and 10(7) colony forming units (CFU), respectively . Response was monitored by titer assessment, using an E coli J5 antigen capture ELISA . Five weeks after the last inoculation, all rabbits were challenged with P multocida and observed for an additional 5 weeks . Clinical, hematologic, serologic, culture, and necropsy data were collected . RESULTS: Inoculation of rabbits with 10(9) CFU of E coli J5 bacterin-induced titers that were significantly greater than titers of rabbits vaccinated with 10(8) or 10(7) CFU or those in controls . The incidence of acute bacteremia was lower in rabbits with high titers . At necropsy, prevalence of lesions typical of P multocida was not significantly different among groups . Prevalence of histologic lesions was also not significantly different among groups . CONCLUSIONS AND CLINICAL RELEVANCE: Although the bacterin induced considerable antibody response and possibly reduced the rate of bacteremia, antibodies were not protective against long-term colonization or infection of the frontal sinuses or tympanic bullae by the challenge strain of P multocida . This bacterin in its currently available form is unlikely to aid in reducing the prevalence of pasteurellosis in rabbits.

Avian Dis, 1999 Apr-Jun, 43(2), 279 - 85
Virulence of raptor-origin Pasteurella multocida in domestic chickens; Aye PP et al.; Pasteurella multocida belonging to somatic serotype 1 and capsular type A has been known to cause avian cholera in domestic poultry . Pasteurella multocida serotype 1 has also been isolated from raptorial birds . However, the capsular type for these raptorial isolates remains unknown . Moreover, the virulence of these raptorial isolates for domestic poultry has not been determined . The objectives of this study were to determine the capsular type of raptorial P . multocida serotype 1 isolates and to determine if these isolates were virulent for domestic chickens . Study chickens were inoculated with one of three P . multocida isolates . Isolate WESO-1 was obtained from a western screech owl (Otus kennicottii) and isolates RTHA-2 and RTHA-4 were isolated from two red-tailed hawks (Buteo jamaicensis) . These isolates were given by either the oral, intravenous, or intraocular route . Control birds were given brain-heart infusion broth . The capsular serotypes of three isolates were also determined . The RTHA-2 and RTHA-4 isolates belonged to P . multocida capsular type A . The WESO-1 isolate belonged to capsular type F . Results also demonstrated that, for the isolates examined, the intraocular route did not cause mortality in chickens . There was mortality in all groups for the intravenous route . However, various mortality patterns were observed when P . multocida was given orally for the three different isolates . The RTHA-4 isolate (serotype 1:A) was the most virulent for domestic chickens . The WESO-1 isolate (serotype 1:F) was the least virulent for chickens among the raptorial isolates examined.

Clin Diagn Lab Immunol, 1999 Jul, 6(4), 617 - 20
Conservation of expression and N-terminal sequences of the Pasteurella haemolytica 31-kilodalton and Pasteurella trehalosi 29-kilodalton periplasmic iron-regulated proteins; Tabatabai LB et al.; This study examined the conservation of expression of a 31-kDa iron-regulated protein by serotypes of Pasteurella haemolytica and Pasteurella trehalosi associated with pasteurellosis of cattle and sheep . A polyclonal antibody prepared against the purified 31-kDa periplasmic iron-regulated protein from P . haemolytica serotype A1 showed that all P . haemolytica serotypes expressed similar 31-kDa proteins with identical N-terminal sequences, whereas P . trehalosi serotypes expressed immunologically different 29-kDa proteins with a different N-terminal sequence . Antibody to the 31-kDa iron-regulated protein was a useful tool to distinguish similarities and differences of the iron-regulated proteins of P . haemolytica and P . trehalosi.

Appl Environ Microbiol, 1999 Jul, 65(7), 2942 - 6
16S rRNA gene sequence analysis of Photobacterium damselae and nested PCR method for rapid detection of the causative agent of fish pasteurellosis; Osorio CR et al.; The causative agent of fish pasteurellosis, the organism formerly known as Pasteurella piscicida, has been reclassified as Photobacterium damselae subsp . piscicida on the basis of 16S rRNA gene sequence comparisons and chromosomal DNA-DNA hybridization data; thus, this organism belongs to the same species as Photobacterium damselae subsp . damselae (formerly Vibrio damselae) . Since reassignment of P . damselae subsp . piscicida was based on only two strains, one objective of the present work was to confirm the taxonomic position of this fish pathogen by sequencing the 16S rRNA genes of 26 strains having different geographic and host origins . In addition, a nested PCR protocol for detection of P . damselae based on 16S rRNA was developed . This PCR protocol was validated by testing 35 target and 24 nontarget pure cultures, and the detection limits obtained ranged from 1 pg to 10 fg of DNA (200 to 20 cells) . A similar level of sensitivity was observed when the PCR protocol was applied to fish tissues spiked with bacteria . The PCR approach described in this paper allows detection of the pathogen in mixed plate cultures obtained from asymptomatic fish suspected to be carriers of P . damselae subsp . piscicida, in which growth of this bacterium cannot be visualized . Our results indicate that the selective primers which we designed represent a powerful tool for sensitive and specific detection of fish pasteurellosis.

J Vet Med Sci, 1999 May, 61(5), 565 - 7
Effects of the lipopolysaccharide-protein complex and crude capsular antigens of Pasteurella multocida serotype A on antibody responses and delayed type hypersensitivity responses in the chicken; Maslog FS et al.; The effects of the lipopolysaccharide-protein complex (LPS) and crude capsular antigen (CCA) prepared from Pasteurella multocida serotype A isolated from a duck in the Philippines, on antibody responses to sheep red blood cells (SRBC) and Brucella abortus (BA) and delayed type hypersensitivity (DTH) responses to bovine serum albumin (BSA) in the chickens were studied . Chickens injected subcutaneously with LPS and CCA at 1 and 2 weeks of age and immunized intravenously with the mixed antigens of SRBC and BA, at 3 and 4 weeks of age showed significantly increased antibody responses against both SRBC and BA, when evaluated at 7 days after each immunization . In addition, these chickens sensitized intramuscularly with the emulsion of BSA in complete Freund's adjuvant at 5 weeks of age, and then injected into the wattle with BSA at 7 weeks of age also showed significantly increased DTH responses against BSA, when evaluated at 24 and 48 hr after challenge . These results indicate that LPS and CCA of P . multocida serotype A have a property enhancing humoral and cell-mediated immune responses.

Presse Med, 1999 May 22-29, 28(19), 1014 - 6
{Pasteurella multocida pneumonia in a lupus patient: microbial identification with alveolar lavage fluid on blood culture medium}; Hazouard E et al.; BACKGROUND: Pasteurella multocida pneumonia mainly occurs in immunodepressed patients . Microbiological proof is difficult to obtain . CASE REPORT: A 36-year-old woman with systemic lupus erythematosus treated with cyclophosphamide and corticosteroids developed pneumonia . She was given amoxicillin-clavulanate . Bronchioalveolar lavage fluid cultures on gelose were negative but Pasteurella multocida grew on blood culture medium . DISCUSSION: Although the direct examination of bronchioalveolar lavage fluid demonstrated Gram negative coccobacilli, gelose cultures were negative, probably because of prior antibiotic therapy . The causal pathogen was only identified when BAL fluid was seeded on blood culture medium, allowing susceptibility tests and subsequent early adaptation of antibiotic therapy . This technique can be helpful in identifying the casual pathogen in microbial pneumonia.

Zentralbl Veterinarmed B, 1999 May, 46(4), 241 - 7
Serotypes of Pasteurella haemolytica and Pasteurella trehalosi isolated from farm animals in Hungary; Fodor L et al.; The biochemical and serological characteristics of 486 P . haemolytica and 31 P . trehalosi strains (517 in total) isolated from different lesions of cattle, sheep, goats, pigs and poultry were examined . A total of 476 P . haemolytica strains (97.9%) showed the characteristics typical of the former biotype A of P . haemolytica, while 10 isolates (2.1%), all from poultry, could not be biotyped . A total of 481 strains (93.0%) could be assigned to one of the 17 serotypes of P . haemolytica-P . trehalosi and 36 strains (7.0%) could not . The majority (83.6%) of the cattle isolates were serotypes A1 and A2 . Among strains isolated from sheep all serotypes of P . haemolytica could be identified with the exception of A14, but serotypes A1, A2, A6, A8 and A5 were the most frequent . The overwhelming majority (94%) of the caprine isolates were A2, other serotypes occurred only sporadically . The pig isolates, which could be isolated only very rarely, represented different serotypes, while none of the 10 strains isolated from poultry could be biotyped or serotyped.

Dtsch Tierarztl Wochenschr, 1999 May, 106(5), 207 - 9
Serotypes and electrophoretic protein profiles of Pasteurella haemolytica isolated from pneumonic ovine lungs; Diker KS et al.; Serotypes and SDS-PAGE protein profiles of P . haemolytica isolated from pneumonic ovine lungs were investigated . Of 268 P . haemolytica isolates, 232 (86.6%) were serotypable . A total of 12 serotypes were recognized in 20 different geographic origins of central Turkey . The most common serotype was A2, followed by A7, A1 and T4 . Serotypes A13, A14, A16 and T15 could not be detected . In SDS-PAGE, marked differences between major bands of biotype A and T strains were found . In numerical analysis of protein profiles, biotype A and T strains were separated at 58% similarity level . Biotype A isolates produced a cluster at 80% similarity level, and biotype T isolates at 92% similarity level . No single cut off level was able to discriminate between each serotype studied and isolates could not be clustered on the basis of their geographic origins.

J Bacteriol, 1999 Jun, 181(12), 3845 - 8
Cloning and characterization of the gene encoding Pasteurella haemolytica FnrP, a regulator of the Escherichia coli silent hemolysin sheA; Uhlich GA et al.; A Pasteurella haemolytica A1 gene was identified from a recombinant library clone that expressed hemolysis in host Escherichia coli cells . The gene, designated fnrP, had sequence identity to E . coli fnr, a global transcriptional regulator of genes required for conversion to anaerobic growth . FnrP complemented anaerobic deficiencies of a fnr-null mutant strain of E . coli and increased expression of the Fnr-dependent, anaerobic terminal reductase gene, frdA . FnrP was purified, identified by immunoblotting, and shown to be nonhemolytic . When FnrP was expressed in E . coli DeltasheA, a null mutant of the cryptic hemolysin SheA, the transformants were nonhemolytic, indicating that FnrP activates this silent hemolysin.

Curr Microbiol, 1999 May, 38(5), 268 - 72
Derivation of extracellular polysaccharide-deficient variants from a serotype A strain of Pasteurella multocida; Champlin FR et al.; The production of serotype A extracellular polysaccharide is thought to be associated with expression of an approximately 40-kDa lipoprotein (P1p-40) present on the outer surface of Pasteurella multocida strains of avian origin . The tendency of certain strains to undergo colonial dissociation concomitantly with serial passaging on laboratory growth media was exploited to derive two variant strains exhibiting the capsule-deficient phenotype from a heavily capsulated parental strain . Assessments of colonial consistency, iridescence, gentian violet binding, and hyaluronidase sensitivity were consistent with cellular observations indicating little or no capsulation of derivative strains . Fluorographic analysis of electrophoretically resolved cellular lipoproteins labeled with {3H}-palmitate revealed capsular loss occurred with a concomitant diminution of P1p-40 production in the variant strains . In contrast, a phenotypically stable strain that did not undergo colonial dissociation under identical conditions exhibited no decrease in P1p-40 content . This work provides a model system for investigating the role of extracellular polysaccharide in the cell surface physiology and pathogenicity of P . multocida . The present results strongly support the notion that P1p-40 is associated with serotype A capsular material and suggest coordinate regulation of their biosynthesis.

Antimicrob Agents Chemother, 1999 Jun, 43(6), 1469 - 74
Linezolid activity compared to those of selected macrolides and other agents against aerobic and anaerobic pathogens isolated from soft tissue bite infections in humans; Goldstein EJ et al.; Linezolid was tested against 420 aerobes and anaerobes, including 148 Pasteurella isolates, by an agar dilution method . Linezolid was active against all Pasteurella multocida subsp . multocida and P . multocida subsp . septica isolates and most Pasteurella canis, Pasteurella dagmatis, and Pasteurella stomatis isolates . The MIC was </=2 microg/ml for staphylococci, streptococci, EF-4b, Weeksella zoohelcum, Fusobacterium nucleatum, other fusobacteria, Porphyromonas spp., Prevotella spp., peptostreptococci, and almost all Bacteroides tectum isolates.

Microb Pathog, 1999 Jun, 26(6), 325 - 31
Cytokine profiles following interaction between bovine alveolar macrophages and Pasteurella haemolytica; Morsey MA et al.; Pasteurella haemolytica is a gram negative bacterium frequently isolated from the lungs of calves suffering from a fibrinous pneumonic condition known as shipping fever . To understand the pathogenesis of this disease, we investigated the induction of cytokin gene expression in cultures of bovine alveolar macrophages (BAM) stimulated with heat-killed P . haemolytica . Northern blot analysis of total RNA showed that P . haemolytica induced early, abundant, and consistent synthesis of IL-1, TNF-alpha, and IL-8 mRNA . Cytokine mRNAs were detected within 1 hr post-stimulation with heat-killed P . haemolytica . IL-1 and IL-8 mRNA accumulated to high levels with increase in stimulation time, whereas TNF-alpha mRNA clearly declined by 4 and 8 h post stimulation . IL-1, TNF-alpha, and IL-8 proteins were also secreted into the culture medium of BAM stimulated with heat-killed P . haemolytica . All three proteins were detected at high levels 8 and 12 h post stimulation with P . haemolytica . BAM cells treated with bovine interferon-alpha and then stimulated with P . haemolytica produced higher amounts of IL-1, IL-8 and TNF-alpha proteins compared to BAM stimulated with P . haemolytica alone . These findings demonstrate the powerful and selective induction of cytokine mRNA and protein synthesis in BAM stimulated with heat-killed P . haemolytica and may explain certain aspects of shipping fever pathogenesis .

Infect Immun, 1999 Jun, 67(6), 2920 - 7
Lipopolysaccharide complexes with Pasteurella haemolytica leukotoxin; Li J et al.; The presence of lipopolysaccharide (LPS) in gram-negative bacterial repeats-in-toxin (RTX) toxin preparations, as well as the harsh conditions required to remove it, suggests that LPS may complex with RTX toxins . Concentrated culture supernatant (CCS) preparations of the RTX toxin Pasteurella haemolytica leukotoxin (LKT) contained LKT and LPS as the most prominent components, with LKT and LPS constituting approximately 30 and 50% of the density of the silver-stained fraction on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), respectively . CCS LKT contained 3.69 +/- 0.46 mg of LPS per mg of protein, which was estimated to indicate an LPS/LKT molar ratio of approximately 60:1 . Subjection of the CCS LKT to preparative SDS-PAGE resulted in separation of LPS from LKT as detected by silver-stained analytical SDS-PAGE; however, the LKT fraction (SDS-PAGE LKT) contained significant endotoxin activity as detected by the Limulus amebocyte lysate assay . Subjection of the SDS-PAGE LKT to a second preparative SDS-PAGE run resulted in a reduction of the LPS/LKT molar ratio to 1:20 . The target cell specificity of LKT for bovine leukocytic cells was retained by the SDS-PAGE LKT, and isolated LPS at comparable concentrations to that in CCS LKT exhibited no leukolytic activity . Addition of isolated LPS back to SDS-PAGE LKT resulted in reconstitution of an LPS-LKT complex . Immediately following reconstitution of the LPS-LKT complex, there was minimal change in leukolytic activity of the complex, but following 9.5 h at temperatures from -135 to 37 degrees C, the LPS-LKT complex exhibited increased leukolytic activity and thermal stability compared to SDS-PAGE LKT . Therefore, it appears that LPS complexes with LKT, resulting in enhanced and stabilized leukolytic activity.

J Emerg Med, 1999 May-Jun, 17(3), 445 - 8
Pasteurella multocida meningitis and septic arthritis secondary to a cat bite; Layton CT; Animal bites are seen almost daily in the emergency department, and the majority heal without complication . Pasteurella multocida is frequently the causative organism of localized wound infections and cellulitis in this patient population . P . multocida infection is usually associated with close contact with pets, such as dogs and cats, that harbor this organism as normal oral flora . Meningitis and septic arthritis are very rare sequelae of P . multocida infection . This case report presents a patient with P . multocida bacteremia, meningitis, and septic arthritis developing together as a complication of a cat bite.

Zentralbl Veterinarmed B, 1999 Apr, 46(3), 145 - 50
Clinical and microbiological study of an otitis media outbreak in calves in a dairy herd; Yeruham I et al.; On a dairy farm, otitis media was diagnosed in 64 suckler calves (21.8%) during a study period of 2 years, and in 10 calves (3.4%) in the third year . The inflammation was unilateral in 63 and bilateral in 11 calves . The affected calves were dull, lacked appetite, were pyrexic and displayed drooping ear or ears and tilted heads with purulent discharge exuding from the external ear canal . Of the affected animals, 56 (87.5%) were aged between 3 and 8 weeks . Morbidity was higher during the calving season and during the autumn and winter months (October-December) . Pasteurella haemolytica was isolated from 21 (32.8%), P . multocida from 20 (31.2%), Actinomyces pyogenes from 11 (17.2%) and Streptococcus pneumoniae from three (4.7%) of the clinically affected calves only during the first two study years . The exudate of the acute ear infections contained, in addition to Pasteurella spp., various bacteria and yeasts . Most of these bacteria were isolated from healthy ears as well, and are likely to be part of the normal ear flora . On the other hand most of the yeasts were isolated from otitic calves . After a short course of an appropriate treatment infections healed in all cases . Possible preventive measures are discussed.

J Med Microbiol, 1999 Mar, 48(3), 279 - 86
Genomic DNA restriction site heterogeneity in bovine Pasteurella multocida serogroup A isolates detected with an rRNA probe; Dabo SM et al.; A total of 81 Pasteurella multocida isolates from healthy and diseased dairy and beef cattle originating from various geographical locations was examined by rRNA gene restriction site polymorphism analysis (ribotyping), restriction endonuclease analysis (REA), SDS-PAGE analysis of whole-cell (WCP) and outer-membrane (OMP) proteins, and capsule and somatic serotyping . Bacterial strains were isolated from nose, lung and in one case testicle, of Holstein and cross-bred beef cattle . The isolates represented for the most part serogroup A3 (88%) . Ribotyping was performed on DNA digested with HaeII, electrophoresed and then hybridised with 32P-labelled 16S-23S rRNA from Escherichia coli . Six ribotypes (R1-R6) and 10 REA types were found among the 81 isolates with similar discrimination index (DI) of c . 0.60 . Protein profiles revealed reproducibility and high levels of polymorphisms among lung isolates . Isolates were compared according to their geographical habitat, their isolation from dairy or from beef cattle and from nasal cavities or lungs . No correlation was apparent between geographical locations and ribotypes . Overall, isolates obtained from dairy cattle were predominantly R1, whereas those obtained from beef cattle were equally distributed between R1 and R2 . R1 was more representative of lung isolates . For some strains, particularly the single isolate ribotypes, good correlation was achieved between WCP analysis, REA types and ribotypes . For others, REA to some extent and WCP profiles were able to discriminate among isolates within ribotypes . The data suggest that a combination of ribotyping, REA and WCP analysis is useful for investigating the epidemiology of bovine P . multocida serogroup A.

J Vet Med Sci, 1999 Mar, 61(3), 283 - 5
Effects of four antigenic fractions of Pasteurella multocida serotype A on phagocytosis of chicken peripheral blood leukocytes; Maslog FS et al.; The effects of four antigenic fractions of Pasteurella multocida serotype A isolated from a duck in the Philippines on the phagocytic activity of chicken peripheral blood leukocytes were studied by a flow cytometer . These fractions were the lipopolysaccharide-protein complex (LPS), crude capsular antigen (CCA), ribosomal fraction (RS) and outer cell layer (OCL) . Among these four antigens, only CCA but not LPS RS and OCL, significantly increased the phagocytic activities of mononuclear cells (MNC) and polymorphonuclear cells (PMN) . This result indicates that CCA has an immunological property enhancing the phagocytic activities of MNC and PMN.

Am J Vet Res, 1999 May, 60(5), 583 - 8
Polymerase chain reaction techniques for differentiating cytotoxic and noncytotoxic Pasteurella trehalosi from Rocky Mountain bighorn sheep; Green AL et al.; OBJECTIVE: To evaluate 2 polymerase chain reaction (PCR)-based methods for differentiating cytotoxic and noncytotoxic Pasteurella trehalosi from Rocky Mountain bighorn sheep (Ovis canadensis canadensis) . SAMPLE POPULATION: 23 isolates of P . trehalosi from bighorn sheep in Colorado, including 18 from free-ranging herds and 5 from a captive herd . PROCEDURE: Using a sequence of the leukotoxin gene region of P . haemolytica serotype 1, 7 PCR primers were designed . A PCR amplification was performed on a sample of bacterial cell suspensions from pure cultures of P . trehalosi with known in vitro cytotoxic effects . The 2 most promising primer pairs were used in a study of 23 P . trehalosi isolates . Results were analyzed for association with cytotoxicity and 3 distinct ribotypes (Eco, Aco, and Bco) . RESULTS: Significant associations were observed between in vitro cytotoxicity and PCR results for coding region, between ribotype Eco classification and PCR results for coding region, and between ribotype Eco classification and PCR results for promoter region . There was a negative association between ribotype Aco classification and PCR results for coding and promoter regions . CONCLUSIONS AND CLINICAL RELEVANCE: The PCR for the leukotoxin A coding region may be useful in differentiating cytotoxic from noncytotoxic P . trehalosi isolates recovered from bighorn sheep . It may be useful for studying epidemiologic features of pasteurellosis in bighorn sheep and for designing vaccines to protect wild sheep against pneumonia caused by P . trehalosi and P . haemolytica.

J Wildl Dis, 1999 Apr, 35(2), 285 - 96
Immunologic responses of domestic and bighorn sheep to a multivalent Pasteurella haemolytica vaccine; Ward AC et al.; The efficacy of a Pasteurella haemolytica vaccine (serotypes A1, A2, and T10) to induce humoral antibodies and alter colonization of the upper respiratory tract by related P . haemolytica spp . strains was evaluated in 10 bighorn (Ovis canadensis canadensis) and 10 domestic (Ovis aries) sheep . Sheep of each species were divided into five pairs based on age and history of respiratory disease . One sheep in each pair was vaccinated twice 2 wk apart with 2 ml of vaccine (VAC group) and the remaining animals (NV group) were injected with 2 ml of sterile saline . Mild, transient lameness was the only observed adverse effect . Blood sera from the sheep were tested for agglutinating antibodies against whole cells of A1, A2, and T10 and for leukotoxin neutralizing antibodies . Antibody titers were expressed as the reciprocal log2 of the highest reactive dilutions . Domestic sheep > 1-yr-old and two bighorn sheep with a history of A1 infection had higher titers throughout the study against A1 cells than domestic sheep < 1-yr-old and bighorns without a history of A1 infection . Both domestic and bighorn sheep had log2 titers of 8 to 12 against A2 cells and 6 to 12 against T10 cells during this time . Bighorn sheep in the VAC group had 2 to 32 fold titer increases for A1 cells by 2 wk post-vaccination (PV) compared to 0 to 2 fold increases in VAC domestic sheep . Two to 16 and 0 to 8 fold increases in antibodies titers to A2 and T10 cells, respectively, were detected in sera of both VAC groups . Sera of bighorn sheep with a history of respiratory disease and all domestic sheep had log2 leukotoxin neutralizing antibody titers of 4 to 14 in contrast to < or = 2 in sera of bighorn sheep without a history of respiratory disease . Neutralizing antibody titers of two bighorns without a history of respiratory disease in the VAC group increased from log2 0 to 5 in one and from 0 to 9 in the other 2 wk PV . Antibody increases in these animals were no longer evident at 16 wk PV while titers of animals with histories of disease remained relatively stable . The types and numbers of Pasteurella spp . isolated from nasal and pharyngeal swabs varied throughout the study without conclusive evidence of suppression of colonization . Although the animals were not experimentally challenged to determine the efficacy of the vaccine, one VAC and one NV bighorn sheep died following introduction of an A2 P . haemolytica strain when leukotoxin neutralizing antibodies had returned to pre-vaccination levels . This vaccine appeared to be safe for use in bighorn sheep and stimulated moderate but transient increases in antibody levels which should provide some protection against naturally occurring disease . A vaccine which would induce production of high and maintained antibodies against multiple strains of P . haemolytica would be valuable for use in bighorn sheep maintained in captivity or when captured for relocation.

FEMS Immunol Med Microbiol, 1999 Apr, 23(4), 273 - 82
Adjuvant and protective properties of native and recombinant Bordetella pertussis adenylate cyclase toxin preparations in mice; Hormozi K et al.; Bordetella pertussis produces a cell-invasive adenylate cyclase toxin which is synthesised from the cyaA gene as an inactive protoxin that is post-translationally activated by the product of the cyaC gene . Purified active and inactive CyaA proteins were prepared from B . pertussis or from recombinant Escherichia coli expressing both cyaA and cyaC genes or the cyaA gene alone . respectively . In addition, a hybrid toxin (Hyb2) in which an internal region of CyaA had been replaced with the analogous region from the leukotoxin (LktA) of Pasteurella haemolytica, and which had low cell-invasive activity, was also prepared from E . coli expressing the cyaC gene . The CyaA preparations showed no evidence of toxicity in a mouse weight-gain test . Active toxin preparations were protective in mice against intranasal challenge with wild-type B . pertussis, as evidenced by lung:body weight ratios and bacterial numbers in the lungs, which were comparable to those in mice given whole-cell DPT vaccine . Hyb2 was not as protective as active CyaA and inactive CyaA preparations were not protective . Active CyaA, when co-administered with ovalbumin (OA), had a marked adjuvant effect on the anti-OA IgG antibody response which was not as apparent with inactive CyaA preparations . Similarly, active CyaA stimulated a greater anti-CyaA response than the inactive form.

Vet Microbiol, 1999 Mar 19, 65(4), 283 - 90
Investigations on the species specificity of Mannheimia (Pasteurella) haemolytica serotyping; Angen O et al.; Eleven serotypes (1, 2, 5-9, 12-14 and 16) have been demonstrated within Mannheimia haemolytica . Subsequent serotyping of 166 Mannheimia haemolytica-like strains, genetically and phenotyphically distinct from Mannheimia haemolytica, and isolated from ruminants, pigs, hares and rabbits showed that 13.2% were typeable, 19 of which were serotype 11 representing strains now being classified as M . glucosida . In addition, three strains belonged to serotypes 6, 9 and 16, respectively . Additionally, the serotyping results of 98 (P.) haemolytica-like isolates from non-ruminant sources collected by the UK Veterinary Investigation Centres during the period 1982-1996 were investigated . None of these isolates have been kept, making further genetic characterization impossible . Among these isolates, 25.5% were typeable representing serotypes 1, 2, 3, 5, 6, 9, 10, 13 and 15 . Substantial evidence has been reported indicating that M . haemolytica-like isolates from non-ruminant sources represent species different from M . haemolytica . The present investigation underlines that serotyping does not represent a reliable method for the identification of M . haemolytica or M . glucosida . These observations emphasize that extended phenotypic and genetic characterization is necessary for the proper identification of these organisms.

Microb Pathog, 1999 May, 26(5), 263 - 73
Pasteurella haemolytica leukotoxin and endotoxin induced cytokine gene expression in bovine alveolar macrophages requires NF-kappaB activation and calcium elevation; Hsuan SL et al.; In bovine alveolar macrophages (BAMs), exposure to leukotoxin (Lkt) and endotoxin (LPS) from Pasteurella haemolytica results in expression of inflammatory cytokine genes and intracellular calcium ({Ca2+}i) elevation . Leukotoxin from P . haemolytica interacts only with leukocytes and platelets from ruminant species . Upregulation of cytokine genes in different cells by LPS involves activation of the transcription factor NF-kappaB (NF-kappaB), resulting in its translocation from the cytoplasm to the nucleus . Using immunocytochemical staining and confocal imaging, we studied whether NF-kappaB activation represents a common mechanism for the expression of multiple cytokine genes in BAMs (Lkt-susceptible cells) stimulated with Lkt and LPS . Bovine pulmonary artery endothelial cells and porcine alveolar macrophages were used as nonsusceptible cells . The role of Ca2+ and tyrosine kinases in NF-kappaB activation and inflammatory cytokine gene expression was studied, since an inhibitor of tyrosine kinases attenuates LPS-induced {Ca2+}i elevation in BAMs . The results are summarized as follows: (a) Lkt induced NF-kappaB activation and {Ca2+}i elevation only in BAMs, while LPS effects were demonstrable in all cell types; (b) chelation of {Ca2+}i blocked NF-kappaB activation and IL-1beta, TNFalpha, and IL-8 mRNA expression; and (c) tyrosine kinase inhibitor herbimycin A blocked expression of all three cytokine genes in BAMs stimulated with Lkt, while only the expression of IL-1beta was blocked in BAMs stimulated with LPS . We conclude that cytokine gene expression in BAMs requires NF-kappaB activation and {Ca2+}i elevation, and Lkt effects exhibit cell type- and species specificity .

Avian Dis, 1999 Jan-Mar, 43(1), 116 - 21
The effect of route of inoculation on the virulence of raptorial Pasteurella multocida isolates in Pekin ducks (Anas platyrhynchos); Pehlivanoglu F et al.; The purpose of this study was to determine the virulence of raptorial Pasteurella multocida for ducks and the effect of various routes of inoculation on virulence . Four-week-old Pekin ducks (Anas platyrhynchos) were challenged with one of three raptorial isolates (RTHA-2, RTHA-4, or WESO-1) by one of five inoculation routes (intranasal, intraocular, intravenous, oral, and subcutaneous) . Ducks were monitored daily for mortality until 2 wk postchallenge . Results indicated that the intravenous route caused the most mortality for all isolates and that significant variation existed in the virulence among the sources of P . multocida, with WESO-1 causing the least mortality of the isolates tested.

Avian Dis, 1999 Jan-Mar, 43(1), 122 - 4
Increased left lung consolidation in turkey cholera related to larger left pulmonary artery; Hopkins BA et al.; After necropsy of the surviving turkeys in a comparative vaccine study for fowl cholera, in the turkeys with only one lung lobe consolidated, a significantly (P < 0.01, chi square test) higher number of turkeys were found with a consolidation of the left lung lobe than with the right lung lobe . When the circumferences of the left and right pulmonary arteries 0.5 cm rostral from the bifurcation were measured and converted to cross-sectional area, the left pulmonary artery had an average area of 29.6 +/- 2.8 mm2, and the right pulmonary artery had an average area of only 22.9 +/- 2.8 mm2, which was nearly one-fourth smaller . This finding suggests that the left lung lobe receives more blood than the right lobe and that, during an acute Pasteurella multocida septicemia, it would receive more of this organism than the right lung lobe.

Avian Dis, 1999 Jan-Mar, 43(1), 83 - 8
Safety and efficacy of two live Pasteurella multocida aro-A mutant vaccines in chickens; Scott PC et al.; Two auxotrophic aro-A mutants of Pasteurella multocida designated PMP1 (serotype 1) and PMP3 (serotype 3) were tested as vaccine candidates to protect chickens against fowl cholera . A reliable intratracheal challenge method was established that resulted in > or = 75% mortality in both specific-pathogen-free chickens and commercial broiler breeders 24 hr after challenge . Dose protection studies indicated that at least 10(6) colony-forming units (CFU) of PMP1 and 10(8) CFU of PMP3 were required to provide complete protection against challenge in all birds . Although high doses of 10(9) CFU of the vaccine strains produced some endotoxinlike reactions, lower but protective dose levels produced no clinical sign or lesion in any chicken . Both vaccine strains provided cross-protection with a heterologous challenge strain PM206 (serotype 4) . Future studies will examine the duration of protective immunity induced by the two vaccine candidates, PMP1 and PMP3, and cross-protection against other serovars.

J Vet Pharmacol Ther, 1999 Feb, 22(1), 13 - 9
Ceftiofur distribution in plasma and joint fluid following regional limb injection in cattle; Navarre CB et al.; The objective of this study was to evaluate the efficacy of regional intravenous (i.v.) injection of ceftiofur in delivery of this drug to joint fluid and plasma in a limb distal to a tourniquet in five, healthy, adult, mixed breed beef cattle . A tourniquet was positioned in the mid-metacarpal region, and 500 mg of ceftiofur was administered through a catheter in the dorsal common digital vein (DCDV) . Plasma samples were collected from the catheter at 15, 30 and 45 min postinjection, and from the abaxial proper palmar vein (APPV) at 15 min postinjection . Synovial fluid was collected from the metacarpal phalangeal joint at 45 min postinjection . Ceftiofur concentrations were estimated in plasma and synovial fluid using high-pressure liquid chromatography (HPLC) and a microbiological assay utilizing Pasteurella haemolytica as the test organism . Both assays indicated highest plasma concentrations of ceftiofur at 15 min, with the concentrations declining with time . Concentrations of ceftiofur in plasma obtained from the DCDV were not significantly different from APPV levels, indicating rapid distribution of ceftiofur within the limb . Microbiological assay always demonstrated higher concentrations of ceftiofur compared with HPLC assay, because the former probably also detected the active metabolites of ceftiofur as well as the parent compound . At 45 min, ceftiofur concentrations determined by HPLC were 251+/-97 and 15+/-5 microg/mL in plasma and synovial fluid, respectively . Regional intravenous injection appears to be a feasible technique to produce rapid distribution of ceftiofur within the limb well above therapeutic concentrations.

Am J Vet Res, 1999 Apr, 60(4), 481 - 4
In vitro efficacy of N-duopropenide, a recently developed disinfectant containing quaternary ammonium compounds, against selected gram-positive and gram-negative organisms; Gutierrez CB et al.; OBJECTIVE: To study the efficacy of N-duopropenide against various gram-positive and gram-negative organisms . SAMPLE POPULATION: One field strain each of Pasteurella multocida subsp multocida, Staphylococcus aureus, Listeria monocytogenes, and L ivanovii, and 2 field strains of Escherichia coli . PROCEDURE: Strains were tested with and without serum as organic matter, using quantitative suspension and carrier tests . Six concentrations of active ingredient (0.005, 0.01, 0.05, 0.11, 0.27, and 0.55%) and 6 contact times (15 and 30 seconds and 1, 3, 5, and 10 minutes) were studied for each . RESULTS: Globally, N-duopropenide was more effective in suspension tests than in carrier tests, and when organisms were suspended in saline solution rather than serum . Under the most disadvantageous conditions (carrier test with serum), a concentration of 0.55% N-duopropenide acting for only 15 seconds was effective in inactivating P multocida subsp multocida and was even more effective against the 2 Listeria species tested . For E coli strains, the same concentration also was effective, but after 10 minutes of contact . On the other hand, N-duopropenide was unable to inactivate the S aureus strain in the carrier test with serum, a concentration of 0.55% for 10 minutes was necessary to inactivate it without organic matter; however, N-duopropenide was highly effective against this organism in the suspension test, even with serum . CONCLUSION: N-duopropenide was highly effective in vitro against 5 of the most commonly encountered organisms in clinical veterinary medicine and, consequently, might be a good choice in control measures against common pathogenic organisms in modern production systems.

Postgrad Med J, 1998 Oct, 74(876), 611 - 2
Fulminant infection by uncommon organisms in animal bite wounds; Dutta JK; In 1995 and 1996, 215 patients exposed to different species of animals were treated at the Amarnath Polyclinic, Balasore, in India . Among them were two children infected by uncommon organisms, i.e., Capnocytophaga canimorsus and Pasteurella multocida; the patients recovered with appropriate antibiotic therapy.

Vet Microbiol, 1999 Mar 12, 65(3), 233 - 40
Cellular and humoral responses in the respiratory tract of goats following intranasal stimulation using formalin-killed Pasteurella haemolytica A2; Zamri-Saad M et al.; A study to determine the immunoglobulin and cellular responses in the respiratory tract of goats following intranasal exposures to formalin-killed Pasteurella haemolytica A2 was carried out . Forty-two goats were divided into two groups . Goats in Group 1 were subjected to double intranasal exposures to formalin-killed P . haemolytica A2 while goats in Group 2 were the unexposed control . Prior to and at weekly intervals post-exposure, three goats from each group were killed, serum samples were collected while the lungs were flushed with 50 ml normal saline before the right apical lobes were fixed in 10% buffered formalin . Both serum and lung lavage fluid were subjected to enzyme-linked immunosorbent assay (ELISA) to determine the levels of IgA, IgM and IgG while the formalin-fixed tissues were examined histologically . IgA levels in the lung lavage fluid increased rapidly to reach a significantly (p < 0.05) high level as early as Week 2 post-exposure and remained significantly (p < 0.05) high throughout the study period . The IgM levels increased at an intermediate rate to reach a significantly (p < 0.05) high level at Week 3 post-exposure before they decreased to an insignificant (p > 0.05) level the following week and the weeks thereafter . IgG levels increased gradually and only reached a significantly (p < 0.01) high level at Weeks 5 and 6 of the study . The size of the bronchus-associated lymphoid tissue (BALT) and the number of lymphocytes in BALT increased significantly from Week 2 and remained high thereafter . However, differences in the numbers of BALT were insignificant (p > 0.05) initially before becoming significantly (p < 0.05) high at Weeks 5 and 6 . The BALT responses were parallel to those of imunoglobulins in the lung lavage fluid.

Vet Microbiol, 1999 Mar 12, 65(3), 215 - 26
Identification of immunogenic, surface-exposed outer membrane proteins of Pasteurella haemolytica serotype 1; Pandher K et al.; Pasteurella haemolytica serotype 1 (S1) is the bacterium most frequently recovered from the lungs of cattle that have succumbed to shipping fever pneumonia . P . haemolytica outer membrane proteins (OMPs) are important immunogens in the development of resistance to pneumonic pasteurellosis . The purpose of this study was to identify the repertoire of immunogenic, surface-exposed P . haemolytica (S1) OMPs, that could be important in the development of protective immunity . We determined surface exposure of OMPs by (1) their susceptibility to protease treatment and (2) their ability to adsorb out antibodies from bovine immune sera . For a comprehensive identification of immunogenic, surface-exposed OMPs, we used bovine antisera from calves that were resistant to experimental P . haemolytica challenge after (1) natural exposure to P . haemolytica, (2) vaccination with live P . haemolytica, or (3) vaccination with P . haemolytica OMPs . We identified 21 immunogenic, surface-exposed P . haemolytica OMPs . Most were recognized by all three immune sera . However, some were recognized by one or two of the three antisera . Our analyses identified surface-exposed, immunogenic proteins that were not identified in previous studies.

FEMS Microbiol Lett, 1999 Mar 15, 172(2), 123 - 9
Role of intracellular calcium in Pasteurella haemolytica leukotoxin-induced bovine neutrophil leukotriene B4 production and plasma membrane damage; Cudd L et al.; Isolated neutrophils were used to study the intracellular calcium ({Ca2+}i) dependency of Pasteurella haemolytica leukotoxin-induced production of leukotriene B4 and plasma membrane damage . Exposure of neutrophils to leukotoxin caused a rapid and concentration-dependent increase in {Ca2+}i, followed by simultaneous plasma membrane damage and production of leukotriene B4 . Removal of extracellular Ca2+, replacement of Ca2+ with other divalent cations, or exposure to high concentration of verapamil, an inhibitor of voltage-dependent calcium channels, inhibited leukotoxin-induced increases in {Ca2+}i, leukotriene B4 production, and membrane damage, thus indicating that influx of extracellular Ca2+ is necessary to produce these leukotoxin-induced neutrophil responses.

Vet Pathol, 1999 Mar, 36(2), 174 - 8
Intranasally inoculated Mycoplasma hyorhinis causes eustachitis in pigs; Morita T et al.; Specific-pathogen-free pigs were experimentally inoculated with Mycoplasma hyorhinis, Pasteurella multocida, or both bacterial isolates to evaluate the role of these bacteria in the pathogenesis of otitis media . Six pigs were inoculated intranasally with 4.4 X 10(8) colony-forming units (CFU) of M . hyorhinis . Twenty-one days later, three of these six pigs were inoculated intranasally with 5.0 X 10(8) CFU of P . multocida . Three additional pigs were also inoculated intranasally at the time with P . multocida alone . Two pigs served as uninoculated controls . Seven days later, all pigs were euthanatized . Histologically, subacute inflammation was found in 10 auditory tubes of six pigs and two tympanic cavities of two pigs inoculated with M . hyorhinis . Immunohistochemically, M . hyorhinis antigens were detected on the luminal surface of eight of 10 inflamed auditory tubes, and ultrastructural examination confirmed mycoplasmal organisms in two pigs . M . hyorhinis was isolated from the inflamed tympanic cavities of two pigs . None of the pigs inoculated only with P . multocida had otitis, and P . multocida was not isolated from the tympanic cavity . These findings indicate that M . hyorhinis can cause eustachitis but rarely otitis media in specific-pathogen-free pigs.

Zentralbl Bakteriol, 1999 Feb, 289(1), 9 - 17
Growth medium affects the cellular fatty acid composition of Pasteurellaceae; Boot R et al.; We studied the cellular fatty acid composition of 10 Actinobacillus (A.) and Pasteurella (P.) reference strains grown on 2 types of agar by the MIDI Microbial Identification System (MIS) . A . capsulatus, A . equuli, A . lignieresii, A . ureae, A . dagmatis, P . gallinarum, P . haemolytica, P . multocida, P . pneumotropica biotypes Heyl and Jawetz were grown on GC agar supplemented with ascitic fluid and X and V factor (Levinthal's agar = LA agar) or GC agar supplemented with vitox and hemoglobin (VH agar) on 3 to 7 and 7 to 16 occasions respectively and fatty acid methylester (FAME) profiles were submitted to principal component analysis (PCA) . All Pasteurellaceae strains showed FAME profiles typical for the family . Maximum coefficients of variation of the percentage of the 3 major FAMEs 14:0, 16:0, and 16:1 cis were 0.03, 0.03 and 0.03 for Pasteurellaceae strains grown on VH agar and 0.09, 0.17 and 0.09 respectively for strains grown on LA agar . PCA of FAME profiles obtained with growth from LA agar generally did not allow species separation of the Pasteurellaceae but most species were clearly discriminated by PCA when they were grown on VH agar . Our findings indicate that the growth medium had a significant effect on the reproducibility of fatty acid profiling in Pasteurellaceae and that PCA of fatty acid data obtained under standardized growth conditions may discriminate Pasteurellaceae species.

FEBS Lett, 1999 Feb 26, 445(2-3), 325 - 8
Regulation of capsular polysialic acid biosynthesis by temperature in Pasteurella haemolytica A2; Barrallo S et al.; The capsular polysaccharide of Pasteurella haemolytica A2 consists of a linear polymer of N-acetylneuraminic acid (Neu5Ac) with alpha(2-8) linkages . The production of this polymer is strictly regulated by the growth temperature and above 40 degrees C no production is detected . Analysis of the enzymatic activities directly involved in its biosynthesis reveals that Neu5Ac lyase, CMP-Neu5Ac synthetase and polysialyltransferase are involved in this regulation . Very low activities were found in P . haemolytica grown at 43 degrees C (at least 25 times lower than those observed when the growth temperature was 37 degrees C) . The synthesis of these enzymes increased rapidly when bacteria grown at 43 degrees C were transferred to 37 degrees C and decreased dramatically when cells grown at 37 degrees C were transferred to 43 degrees C . These findings indicate that the cellular growth temperature regulates the synthesis of these enzymes and hence the concentration of the intermediates necessary for capsular polysaccharide genesis in P . haemolytica A2.

J Antibiot (Tokyo), 1999 Jan, 52(1), 52 - 60
Studies on time-kill kinetics of different classes of antibiotics against veterinary pathogenic bacteria including Pasteurella, Actinobacillus and Escherichia coli; Norcia LJ et al.; A systematic analysis of the bacteriostatic/bactericidal effect of several antibiotics used in veterinary medicine was carried out by time-kill kinetic analysis using P . haemolytica, P . multocida, A . pleuropneumoniae, and E . coli . The antibiotics tested were enrofloxacin, danofloxacin, erythromycin, tilmicosin, penicillin G, ceftiofur and tetracycline . Unexpectedly, the antibiotics well characterized as bacteriostatic agents against human pathogens such as tetracycline and macrolides, showed bactericidal activity against P . haemolytica and A . pleuropneumoniae . In contrast, tetracycline and erythromycin were bacteriostatic and tilmicosin was bactericidal against P . multocida . In addition, P . multocida was killed by fluoroquinolones at a slower rate than the other bacteria . Spectrum analysis revealed that ceftiofur and tilmicosin were good substrates of the universal efflux pump, AcrA/B, but penicillin and tetracycline were not . The fluoroquinolones were modest substrates for AcrA/B.

Lab Anim Sci, 1999 Feb, 49(1), 49 - 53
Identification by 16S rDNA fragment amplification and determination of genetic diversity by random amplified polymorphic DNA analysis of Pasteurella pneumotropica isolated from laboratory rodents; Kodjo A et al.; Pasteurella pneumotropica is an opportunistic bacterium frequently isolated from colonies of various laboratory rodents . Identification of this species, including its differentiation into two distinct biotypes (Jawetz and Heyl), is usually based on the use of conventional bacteriologic methods . In this study, a 16S rDNA fragment amplification procedure was developed for use as an alternative method for identification and differentiation of P . pneumotropica . Polymerase chain reaction (PCR) products were two distinctive fragments of 937 and 564 bp specific for biotypes Jawetz and Heyl, respectively . Specificity of PCR products could be achieved by EcoRI cleavage, leading to 596 plus 341-bp and 346 plus 218-bp fragments for each of the amplification products . Use of this procedure confirmed identification of 34 field isolates and allowed definitive identification of some strains that could not have been done by use of bacteriologic examinations . Field isolates subjected to random amplified polymorphic DNA (RAPD) analysis had high genetic diversity among biotype Jawetz strains in contrast to biotype Heyl strains . In conclusion, RAPD could represent an additional means for identification of ambiguous strains of biotype Heyl and a valuable epidemiologic tool for identification of biotype Jawetz strains of P . pneumotropica.

Microb Pathog, 1999 Apr, 26(4), 183 - 93
Evidence of Pasteurella haemolytica linked immune complex disease in natural and experimental models; McBride JW et al.; The pathogenesis of bovine pneumonic pasteurellosis is not completely understood, and studies have not established that Pasteurella haemolytica A1 (Ph1) virulence is exclusively responsible for the development of acute pulmonary lesions . The purpose of this investigation was to determine if immune complex disease is involved in the pathogenesis of bovine pneumonic pasteurellosis . A retrospective immunohistologic study of lung tissue from natural cases of bovine pneumonic pasteurellosis (44) as performed, and immune complexes were observed in alveloar spaces and walls in 88% of these cases . To study this pathologic mechanism experimentally, groups of mice were immunized with purified Ph1 outer membranes (OMs) or sham immunized on days 0 and 14 . Mice were challenged intratracheally on day 24 with either live Ph1 or Ph1 OMs, and pulmonary lesions were assessed 24 h after challenge . Placebo immunized mice developed focal infiltrates of neutrophils and macrophages centered around large caliber bronchi . Mice immunized with Ph1 OMs and challenged with live Ph1 or OMs developed severe bronchointerstitial pneumonia with diffuse neutrophilic infiltration, focal necrosis, hemorrhage and edema, that is histologically similar to bovine pneumonic pasteurellosis . Immunohistology revealed flocculent aggregates of IgG and complement positive material within alveolar spaces and walls from mice challenged with live Ph1, and fine granular deposits of IgG and complement positive material were observed lining the alveolar walls from mice challenged with Ph1 OMs . Immunized mice exhibited high serum IgG antibody titers to Ph1 outer membrane proteins (OMPs) . Results of this study suggest that immune complex disease plays a role in the pathogenesis of bovine pneumonic pasteurellosis .

Berl Munch Tierarztl Wochenschr, 1997 Oct, 110(10), 386 - 90
{Investigation of outer membrane proteins of Pasteurella . 2: Iron-regulated outer membrane proteins of Pasteurella multocida and Pasteurella haemolytica}; Geschwend G et al.; Pasteurella multocida and Pasteurella haemolytica produce specific proteins in the outer membrane under iron-depleted conditions . Pasteurella multocida serovar A expresses these proteins of molecular masses of 76 and 96 kDa as determined by electrophoresis . The analogous serovar D produces a further iron-regulated protein of 85 kDa . The Pasteurella haemolytica strains of serovar A1, A6 and T contain iron-regulated outer membrane proteins of molecular masses of 71, 77 and 100 kDa . These proteins possess binding positions for iron ions . Both Pasteurella multocida and Pasteurella haemolytica strains utilize iron from porcine and bovine transferrin, but not from haemin and haemoglobin.

Berl Munch Tierarztl Wochenschr, 1997 Oct, 110(10), 381 - 5
{LPS receptor expression and lps binding capacity of monocytes and macrophages in swine}; Berndt A et al.; The expression of the lipopolysaccharide (LPS) receptor CD14, being of importance for an effective immune response, and the direct measurable binding of LPS molecules by alveolar macrophages (AM), peritoneal macrophages (PM) and peripheral blood mononuclear cells (PBMC) of swine were determined . Additionally, the influence of an experimental intrabronchial infection with Pasteurella multocida on these parameters was investigated . Whereas the AM and the PM differed only negligibly regarding their share of CD14 bearing and LPS binding cells, in contrast to AM the intensity of the LPS-binding of PM was significantly higher . Among the PBMC, two populations could be detected which expressed the CD14 with different intensity, whereas the LPS-binding of both populations was similarly pronounced . Following infection of the animals, AM showed an unchanged percentage of CD14 positive cells and simultaneously an increased CD14 receptor expression . On the other hand, the percentage of the LPS-binding cells rose, while no changes of the intensity of LPS-binding were observable . The studies revealed that intrabronchial infection results in local and systemic alterations of CD14 expression and LPS-binding capacity of different cell populations . However, a direct correlation between the appearance of CD14- and LPS-binding does not seem to inevitably exist, indicating probably CD14-independent LPS-binding.

Berl Munch Tierarztl Wochenschr, 1997 Oct, 110(10), 378 - 80
{Experimental affecting of pulmonary clearance of Pasteurella multocida induced pneumonia in swine}; Muller G et al.; The pulmonary clearance of Pasteurella multocida in weaner pigs was not affected by Carrageenan and Silica, two substances which block the function of monocytes/macrophages . Neutropenia, caused by the application of hydroxyurea, however, inhibit the pulmonary clearance markedly and reduced the severity of simultaneously induced pneumonias considerably . This indicates the importance of polymorphonuclear neutrophils for early clearance mechanisms and their inflammation inducing and maintaining effects.

Berl Munch Tierarztl Wochenschr, 1997 Oct, 110(10), 365 - 8
{Long-chain fatty acids of Pasteurella multocida nad Pasteurella haemolytica}; Erler W et al.; The relative contents of long-chain fatty acids in P . multocida and P . haemolytica were investigated . A dependence on the composition of the broth was established . Accordingly, comparative quantitative studies on fatty acid contents have to be conducted using bacteria grown with the same lot of broth medium . As for P . multocida, there were significant differences between the serovars (C14 in TDHM and C16, delta 2C18 in BPL) . These differences are, however, not significant to replace serotyping . Highly significant differences were also detected between P . multocida isolates from nasal swabs and pneumonic lungs (interims of C14, delta C16 on BPL and BRU) . The largest differences were measured for strains grown on BRU, which is interpreted as an expression of virulence . Significant differences were found between biotypes A and T of P . haemolytica, namely for C14, C16 in TDHM, and C14, delta C16, C16, C18 in BPL medium.

Vet Microbiol, 1999 Mar 1, 65(2), 153 - 66
Pasteurella haemolytica leukotoxin induced apoptosis of bovine lymphocytes involves DNA fragmentation; Sun Y et al.; It has been reported that Pasteurella haemolytica leukotoxin (LKT) induces morphologic changes in bovine leukocytes consistent with apoptosis in vitro, but DNA fragmentation was not observed . We investigated whether bovine lymphocytes undergo DNA fragmentation during LKT-induced apoptosis . Bovine peripheral blood lymphocytes were isolated by density gradient centrifugation and exposed to LKT or inactive pro-LKT protein from a lktC- mutant strain . After exposure, DNA fragmentation in lymphocytes was quantified colorimetrically by diphenylamine assay and visualized by agarose gel electrophoresis . At high LKT concentrations, bovine lymphocytes were lysed, but at low concentrations, LKT caused DNA fragmentation characteristic of apoptosis . Maximal DNA fragmentation in bovine lymphocytes was induced by 0.1 TU ml(-1) LKT following 3 h exposure, but only background level of DNA fragmentation was observed with the inactive pro-LKT . Equine lymphocytes that are resistant to LKT intoxication did not show DNA fragmentation following exposure to LKT . Preincubation of LKT with a neutralizing anti-LKT monoclonal antibody inhibited LKT-induced DNA fragmentation . Electrophoresis of DNA from bovine lymphocytes treated with 0.1 TU ml(-1) LKT demonstrated the typical 'ladder' pattern of internucleosomal DNA cleavage, the hallmark of apoptosis associated with activation of endonucleases . LKT-induced DNA fragmentation was inhibited by 0.5 mM ZnCl2, an endonuclease inhibitor . The results indicated that LKT at low concentrations induced apoptotic cell death of bovine lymphocytes, which may play a role in initiation and persistence of P . haemolytica infection.

Vet Immunol Immunopathol, 1999 Feb 1, 67(2), 161 - 70
Primary and anamnestic responses of bovine bronchoalveolar and peripheral blood lymphocyte subsets to aerosolized Pasteurella haemolytica A1; McBride JW et al.; Site-specific responses of bronchoalveolar and peripheral blood lymphocyte subsets were compared during primary and anamnestic immune responses against live Pasteurella haemolytica A1 (Ph1) . Eight 1-year old calves were sequentially exposed intrabronchially with aerosolized Ph1 on days 0, 14, and 21, and two calves were sham exposed . Bronchoalveolar and peripheral blood lymphocytes were analyzed before each Ph1 exposure, and on days 3 and 7 post exposure using single and two-color flow cytometry to identify CD2+, CD4+, CD8+, CD21+, CD45R+, CD25+ and gammadelta lymphocyte subsets . Significant differences (p < 0.05) in bronchoalveolar and peripheral blood lymphocyte subsets were observed before Ph1 exposure . Subsequent aerosol exposures, resulted in significant (p < 0.05) changes in bronchoalveolar lymphocyte subsets and the CD4:CD8 bronchoalveolar lymphocyte ratio, but concomitant changes were not observed in peripheral blood lymphocytes . Expression of CD2, CD4 and CD8 lymphocyte differentiation antigens was consistently lower and more heterogeneous on bronchoalveolar lymphocytes . Differential analysis of bronchoalveolar leukocytes revealed a significant increase in bronchoalveolar lymphocytes and neutrophils during anamnestic responses.

Microbiology, 1999 Feb, 145 ( Pt 2), 483 - 94
Superoxide dismutase and catalase in Photobacterium damselae subsp . piscicida and their roles in resistance to reactive oxygen species; Barnes AC et al.; Photobacterium damselae subsp . piscicida (formerly Pasteurella piscicida) is the causative agent of pasteurellosis or pseudotuberculosis in warm water marine fish . Enzymes which neutralize reactive oxygen species, produced during aerobic metabolism or during respiratory burst in fish macrophages, are important virulence factors in many pathogens . This study characterizes a periplasmic superoxide dismutase (SOD) and a cytoplasmic catalase in P . damselae . Purification and partial amino-terminal sequencing confirmed the SOD to be iron-cofactored, with a high degree of homology to other bacterial FeSODs . The SOD was common to all strains analysed in terms of type, location and activity, whilst the catalase varied in activity between strains . The catalase was constitutively expressed, but the SOD appeared to be repressed under low oxygen conditions . In spite of the presence of a periplasmic SOD, P . damselae was susceptible to killing by exogenous superoxide anion generated in a cell-free system . Addition of exogenous SOD to this system did not abolish the bactericidal effect; however, addition of catalase was protective . These results suggest that lack of periplasmic catalase may be implicated in susceptiblity to killing by reactive oxygen species.

Vet Microbiol, 1999 Feb 23, 65(1), 61 - 74
Development of a typing system for epidemiological studies of porcine toxin-producing Pasteurella multocida ssp . multocida in Denmark; Fussing V et al.; The aim of the present study was to evaluate capsular-typing, plasmid-profiling, phage-typing and ribotyping for epidemiological studies of toxin-producing Pasteurella multocida ssp . multocida in Denmark . The evaluation of methods was based on 68 strains from nasal swabs and 14 strains from pneumonic lungs . Strains from lungs were all of capsular Type A, whereas strains from nasal swabs were of both capsular Types A and D . Only 9% of the strains contained plasmids, which could not be associated with antibiotic resistance . Phage-typing divided 61% of strains into 10 groups, while 39% were non-typable . CfoI ribotyping divided strains into four groups of which one type contained 94% of isolates . HindIII ribotyping divided strains into 18 types . A total of 18 strains from The Netherlands, UK and USA were subjected to HindIII ribotyping, resulting in 13 types of which six were identical to ribotypes of Danish strains . Phage-typing of isolates from an outbreak of atrophic rhinitis involving six herds in 1985 showed the existence of an epidemic strain . This type was recognised in the herd suspected of being the source of the infections and in four of the five infected herds . These findings were supported by HindIII ribotyping, as 85% of isolates from all herds were assigned to one ribotype . In conclusion, HindIII ribotyping seems to represent a useful tool for epidemiological studies of toxigenic P . multocida ssp . multocida.

Vaccine, 1999 Feb 26, 17(7-8), 821 - 31
Sequence analysis of Pasteurella multocida major outer membrane protein (OmpH) and application of synthetic peptides in vaccination of chickens against homologous strain challenge; Luo Y et al.; Pasteurella multocida major outer membrane protein (OmpH) has been previously characterized as a porin . The native OmpH from strain X-73 (serotype 1) but not recombinant protein from Escherichia coli induced homologous protection in chickens . In this study OmpH sequences from 15 P . multocida serotypes as well as the CU vaccine strain were compared by sequence alignment and revealed high homology, with major variations confined to two discrete regions which were correspondingly predicted as two largest external loops . Secondary structures of OmpHs were predicted by sequence alignment of OmpHs with well defined porins and analyses of amphiphilicity, hydrophobic moment and antigenic index plots . Several synthetic peptides derived from predicted loop 2 and loop 5 of X-73 OmpH were synthesized as vaccine candidates . Vaccination studies in chickens showed that the cyclic synthetic peptide (Cyclic-L2) mimicking the predicted loop 2 induced 70% protection in chickens against strain X-73 challenge . This is the first report that a synthetic peptide mimicking the conformational epitopes of a native protein provide practical protection in target animal against bacterial infection.

Exp Anim, 1999 Jan, 48(1), 51 - 4
Evaluation of PCR as a means of identification of Pasteurella pneumotropica; Nozu R et al.; A polymerase chain reaction with new primers (new PCR) designed from Pasteurella pneumotropica 16S rDNA as an identification system for this organism was compared with the PCR reported by Wang et al . (Wang's PCR) by using 15 bacterial reference species and 70 clinical isolates with the conventional identification system . For the 15 reference strains, both PCRs were identical . For the 70 clinical isolates, the new PCR and Wang's PCR showed consistency with the conventional system in 62.9% (44/70) and 51.4% (36/70), respectively . Twenty-six isolates were inconsistent with the conventional system and the new PCR with respect to morphology and serology . These findings suggested that the new PCR was more sensitive than Wang's PCR, and the new PCR in combination with morphology and serology is useful for P . pneumotropica identification.

Clin Diagn Lab Immunol, 1999 Mar, 6(2), 199 - 203
Contributory and exacerbating roles of gaseous ammonia and organic dust in the etiology of atrophic rhinitis; Hamilton TD et al.; Pigs reared commercially indoors are exposed to air heavily contaminated with particulate and gaseous pollutants . Epidemiological surveys have shown an association between the levels of these pollutants and the severity of lesions associated with the upper respiratory tract disease of swine atrophic rhinitis . This study investigated the role of aerial pollutants in the etiology of atrophic rhinitis induced by Pasteurella multocida . Forty, 1-week-old Large White piglets were weaned and divided into eight groups designated A to H . The groups were housed in Rochester exposure chambers and continuously exposed to the following pollutants: ovalbumin (groups A and B), ammonia (groups C and D), ovalbumin plus ammonia (groups E and F), and unpolluted air (groups G and H) . The concentrations of pollutants used were 20 mg m-3 total mass and 5 mg m-3 respirable mass for ovalbumin dust and 50 ppm for ammonia . One week after exposure commenced, the pigs in groups A, C, E, and G were infected with P . multocida type D by intranasal inoculation . After 4 weeks of exposure to pollutants, the pigs were killed and the extent of turbinate atrophy was assessed with a morphometric index (MI) . Control pigs kept in clean air and not inoculated with P . multocida (group H) had normal turbinate morphology with a mean MI of 41.12% (standard deviation {SD}, +/- 1 . 59%) . In contrast, exposure to pollutants in the absence of P . multocida (groups B, D, and F) induced mild turbinate atrophy with mean MIs of 49.65% (SD, +/-1.96%), 51.04% (SD, +/-2.06%), and 49.88% (SD, +/-3.51%), respectively . A similar level of atrophy was also evoked by inoculation with P . multocida in the absence of pollutants (group G), giving a mean MI of 50.77% (SD, +/-2.07%) . However, when P . multocida inoculation was combined with pollutant exposure (groups A, C, and E) moderate to severe turbinate atrophy occurred with mean MIs of 64.93% (SD, +/-4.64%), 59.18% (SD, +/-2.79%), and 73.30% (SD, +/-3.19%), respectively . The severity of atrophy was greatest in pigs exposed simultaneously to dust and ammonia . At the end of the exposure period, higher numbers of P . multocida bacteria were isolated from the tonsils than from the nasal membrane, per gram of tissue . The severity of turbinate atrophy in inoculated pigs was proportional to the number of P . multocida bacteria isolated from tonsils (r2 = 0.909, P < 0.05) and nasal membrane (r2 = 0.628, P < 0.05) . These findings indicate that aerial pollutants contribute to the severity of lesions associated with atrophic rhinitis by facilitating colonization of the pig's upper respiratory tract by P . multocida and also by directly evoking mild atrophy.

Vet Microbiol, 1999 Feb 12, 64(4), 307 - 21
Actin polymerization enhances Pasteurella haemolytica leukotoxicity; Basaraba RJ et al.; Pasteurella haemolytica leukotoxin is cytotoxic to bovine leukocytes, causing increased cell membrane permeability, osmotic swelling, release of cytosolic proteins and cell lysis . These studies were designed to test if leukotoxin causes release of the cytoskeletal protein, actin, from bovine leukemia cells and if purified actin-influenced bacterial growth or leukotoxin production . Culture supernatants caused a 7-fold decrease in viability of bovine leukemia cells and increased cell permeability that was accompanied by release of beta-actin into the cell culture supernatant . Exposing P . haemolytica to purified actin solutions induced the conversion of monomeric G-actin to polymerized F-actin . This conversion was partially inhibited by bovine P . haemolytica immune, but not pre-immune, serum . Loss of streptomycin resistance following treatment of the organism with acridine orange ablated the polymerizing activity . Incubation of P . haemolytica in the presence of purified F-actin did not affect growth but resulted in culture supernatant that had 3.0-3.9-fold greater leukotoxicity compared to medium alone or medium containing G-actin, heat-denatured actin or albumin . The effect of actin on leukotoxicity was concentration-dependent and directly associated with increases in secreted leukotoxin . The interaction between P . haemolytica and actin is potentially detrimental to the host by inducing polymerization of actin into insoluble filaments and by enhancing leukotoxicity.

Glycoconj J, 1998 Sep, 15(9), 855 - 61
Biochemical conditions for the production of polysialic acid by Pasteurella haemolytica A2; Puente-Polledo L et al.; The capsular polysaccharide of Pasteurella haemolytica A2 consists of a linear polymer of N-acetylneuraminic acid (Neu5Ac) with alpha(2-8) linkages . When the bacterium was grown at 37 degrees C for 90 h in 250 ml shake flasks at 200 rpm in Brain heart infusion broth (BHIB), it accumulated, attaining a level of 60 microg/ml . Release of this polymer was strictly regulated by the growth temperature, and above 40 degrees no production was detected . The pathway for the biosynthesis of this sialic acid capsular polymer was also examined in P . haemolytica A2 and was seen to involve the sequential presence of three enzymatic activities: Neu5Ac lyase activity, which synthesizes Neu5Ac by condensation of Nacetyl-D-mannosamine and pyruvate with apparent Km values of 91 mM and 73 mM, respectively; a CMP-Neu5Ac synthetase, which catalyzes the production of CMP-Neu5Ac from Neu5Ac and CTP with apparent Km values of 2 mM and 0.5 mM, respectively, and finally a membrane-associated polysialyltransferase, which catalyzes the incorporation of sialic acid from CMP-Neu5Ac into polymeric products with an apparent CMP-Neu5Ac Km of 250 microM.

Nucleic Acids Res, 1999 Mar 15, 27(6), 1505 - 11
Characterization of a CACAG pentanucleotide repeat in Pasteurella haemolytica and its possible role in modulation of a novel type III restriction-modification system; Ryan KA et al.; In a previous study, a recombinant plasmid that contains a CACAG pentanucleotide repeat was isolated from a Pasteurella haemolytica A1 library . Southern hybridization analysis using a (CACAG)5probe indicated the presence of two loci that contain the pentanucleotide repeats on the genome of P.haemolytica A1 . Additional hybridization analyses against genomic DNA from related microorganisms indicated that the repeats are only present in P.haemolytica and Pasteurella trehalosi T3 . The various serotypes of P.haemolytica werefound to have either one or two of the CACAG repeat-containing loci . Examination of the locus designated Rpt2 by PCR and sequence analysis indicated that the number of CACAG repeats could change upon serial subculture which most likely occurs as a result of DNA slipped-strand mispairing . A plasmid carrying the Rpt2 locus was isolated and characterized . Sequenceanalysis indicated that the CACAG repeats are contained within the 5'-end of a gene that showed homology to mod genes of type III restriction-modification systems . A second open reading frame downstream was identified which showed homology to res genes of type III restriction-modification systems . Both the modification and restriction proteins could be expressed and polypeptides of the expected sizes were detected by SDS-PAGE . Restriction activity could also be detected in crude cytoplasmic extracts of Escherichia coli strains carrying the mod and res genes on recombinant plasmids.

Int J Syst Bacteriol, 1999 Jan, 49 Pt 1, 207 - 16
Actinobacillus succinogenes sp . nov., a novel succinic-acid-producing strain from the bovine rumen; Guettler MV et al.; Strain 130ZT was isolated from the bovine rumen . It is a facultatively anaerobic, pleomorphic, Gram-negative rod . It exhibits a 'Morse code' form of morphology, which is characteristic of the genus Actinobacillus . Strain 130ZT is a capnophilic, osmotolerant succinogen that utilizes a broad range of sugars . It accumulates high concentrations of succinic acid (> 70 g l-1) . Strain 130ZT is positive for catalase, oxidase, alkaline phosphatase and beta-galactosidase, but does not produce indole or urease . Acid but no gas is produced from D-glucose and D-fructose . 16S rRNA sequence analysis places strain 130ZT within the family Pasteurellaceae; the most closely related members of the family Pasteurellaceae have 16S rRNA similarities of 95.5% or less with strain 130ZT . Strain 130ZT was compared with Actinobacillus lignieresii and the related Bisgaard Taxa 6 and 10 . Based upon morphological and biochemical properties, strain 130ZT is most similar to members of the genus Actinobacillus within the family Pasteurellaceae . It is proposed that strain 130ZT be classified as a new species, Actinobacillus succinogenes . The type strain of Actinobacillus succinogenes sp . nov . is ATCC 55618T.

Int J Syst Bacteriol, 1999 Jan, 49 Pt 1, 67 - 86
Taxonomic relationships of the {Pasteurella} haemolytica complex as evaluated by DNA-DNA hybridizations and 16S rRNA sequencing with proposal of Mannheimia haemolytica gen . nov., comb . nov., Mannheimia granulomatis comb . nov., Mannheimia glucosida sp . nov., Mannheimia ruminalis sp . nov . and Mannheimia varigena sp . nov; Angen O et al.; The present paper presents the conclusions of a polyphasic investigation of the taxonomy of the trehalose-negative {Pasteurella} haemolytica complex . Clusters previously identified by ribotyping and multilocus enzyme electrophoresis (MEE) have been evaluated by 16S rRNA sequencing and DNA-DNA hybridizations . Results obtained by the different techniques were highly related and indicated that the {P.} haemolytica complex contains distinct genetic and phenotypic groups . At least seven species were outlined, five of which were named . We refrained in formal naming of more groups until additional strains are characterized . Five 16S rRNA clusters were identified corresponding to distinct lineages previously outlined by MEE . Within 16S rRNA cluster I two distinct genotypic groups have been outlined in addition to {P.} haemolytica sensu stricto (biogroup 1) . Each of the clusters II, III, IV and V represent at least one new species . The investigations underline that {P.} haemolytica sensu stricto only contains strains that do not ferment L-arabinose even though they are referred to as 'biotype A' of {P.} haemolytica . The five 16S rRNA clusters identified had a common root relative to the other species within the family Pasteurellaceae, and the overall sequence similarity among these five clusters was higher than what is observed within the existing genera of the family . The allocation of the trehalose-negative {P.} haemolytica complex to a new genus seems to be indicated . Based on the polyphasic investigation performed a new genus Mannheimia is proposed for the trehalose-negative {P.} haemolytica complex . At the present stage two previously named species are transferred to this new genus and three new species are described . {P.} haemolytica is reclassified as Mannheimia haemolytica comb . nov., whereas Pasteurella granulomatis, Bisgaard taxon 20 and {P.} haemolytica biovar 3J are reclassified and combined in the species Mannheimia granulomatis comb . nov . Mannheimia glucosida sp . nov . corresponds to {P.} haemolytica biogroups 3A-3H and the beta-glucosidase and meso-inositol-positive strains of {P.} haemolytica biogroup 9 . All typable strains within M . glucosida belong to serotype 11 . Mannheimia ruminalis sp . nov . consists of strains previously classified as Bisgaard taxon 18 and {P.} haemolytica biogroup 8D . Finally, Mannheimia varigena sp . nov . includes {P.} haemolytica biogroup 6 as well as Bisgaard taxon 15 and Bisgaard taxon 36 . The type strains are NCTC 9380T (M . haemolytica), ATCC 49244T (M . granulomatis), CCUG 38457T = P925T (M . glucosida), CCUG 38470T = HPA92T (M . ruminalis) and CCUG 38462T = 177T (M . varigena).

Infect Immun, 1999 Mar, 67(3), 1292 - 6
Enhanced adhesion of Pasteurella multocida to cultured turkey peripheral blood monocytes; Pruimboom IM et al.; Capsular hyaluronic acid (HA) mediates adhesion of serogroup A strains of Pasteurella multocida to elicited turkey air sac macrophages (TASM) . In contrast, freshly isolated turkey peripheral blood monocytes (TPBM) do not bind serogroup A strains . Following culture of TPBM for 6 days in chamber slides, adhesion of the bacteria to TPBM increased gradually . Incubation in chamber slides coated with entactin-collagen IV-laminin (ECL) attachment matrix or exposure to phorbol myristate acetate (PMA) further enhanced the adhesion of P . multocida to TPBM . Addition of HA, but not Arg-Gly-Asp peptide, to TPBM culture inhibited bacterial adherence similarly to the inhibition previously reported for TASM . Exposure of TPBM to monoclonal antibody directed against HA-binding cell surface proteoglycan (CD44) decreased binding of P . multocida . Collectively, these findings indicate that P . multocida adhesion to TPBM is mediated by capsular HA and can be increased by culture on ECL attachment matrix or PMA exposure . Additionally, the findings suggest that the capsular mucopolysaccharide of serogroup A strains of P . multocida recognizes an isoform of CD44 expressed on cultured TPBM.

J Med Microbiol, 1999 Feb, 48(2), 125 - 31
Characterisation of dermonecrotic toxin-producing strains of Pasteurella multocida subsp . multocida isolated from man and swine; Donnio PY et al.; Thirty-six isolates, from man or swine, of Pasteurella multocida subsp . multocida producing (n = 13) or not producing (n = 23) the dermonecrotic toxin (DNT) were studied by numerical analysis, capsular typing and ribotyping . Toxigenic strains were also characterised by restriction fragment length polymorphism (RFLP) of the toxA gene and pulsed-field gel electrophoresis (PFGE) . Numerical analysis differentiated the Pasteurella species and subspecies, but did not discriminate between toxigenic and nontoxigenic strains . RFLP demonstrated that toxA was located in a conserved part of the chromosome of all toxigenic strains . Ribotyping provided evidence of a close association between DNT production and one of the six EcoRI ribotypes designated as E2 . In contrast, PFGE provided evidence for significant DNA polymorphism amongst the toxigenic strains . Results of phenotypic and genotypic studies suggested that toxigenic strains do not form a clone within the subspecies multocida . No difference was found between toxigenic strains of porcine or human origin by biochemical characterisation, capsular serotyping or genomic typing methods.

Zentralbl Bakteriol, 1998 Dec, 288(4), 491 - 9
Problems of identification in clinical microbiology exemplified by pig bite wound infections; Lindberg J et al.; Our experience from attempts to identify bacteria isolated from boar bite/gore wounds is the background for a discussion of identification problems . Some organisms, although not very common or well-known, can be identified when using commercial kits or conventional methods, provided they are sufficiently characterized, as exemplified by Pasteurella aerogenes isolated from cases 1 and 2 . Some organisms may be wrongly identified, or not identified, by both commercial kits and conventional methods, unless seen by experienced microbiologists with knowledge of the original literature . This is exemplified by case 3, in which the final identification result was Bisgaard's taxon 15 . Sometimes isolates cannot be identified even in reference laboratories and by using available identification tables and databases . In such cases, the organism involved may turn out to belong to a previously undescribed taxon . This is illustrated by the strains isolated from cases 4 and 5.

J Emerg Med, 1999 Jan-Feb, 17(1), 189 - 95
Targeting lurking pathogens in acute traumatic and chronic wounds; Eron LJ; The appropriate antimicrobial treatment for skin and soft tissue following acute trauma is determined by the mechanism of injury, time from injury to treatment, environmental wound contamination, pathogenicity of colonizing bacteria, and patient-specific issues . These factors can be used to predict the risk of secondary infection of wounds . Although common skin pathogens (such as Staphylococcus aureus and group A Streptococcus) cause most secondary wound infections, antibiotic therapy sometimes must be directed against unusual pathogens that are associated with atypical wounds, such as animal bites (amoxicillin with clavulanate for Pasteurella multocida) and plantar puncture wounds (ciprofloxacin for Pseudomonas aeruginosa) . This customized treatment approach is also appropriate for chronic wounds, such as pressure and diabetic foot ulcers . In addition to antibiotic therapy, wound management may include surgical debridement . Active areas of investigation in wound management include the use of growth factors and hyperbaric oxygen.

Zh Mikrobiol Epidemiol Immunobiol, 1998 Nov-Dec, (6), 11 - 6
{Capsule formation in Pasteurella multocida, serovar A}; Popova TE et al.; In this work the process of capsule formation in P.multocida bovine strain, serovar A, has been studied . The cultures were grown on liquid and solid nutrient media prepared on the basis of Hottinger hydrolysate and synthetic culture medium 199 . Extracellular material was detected by the method electron cytochemistry with ruthenium red and polycationic ferritin . As revealed by specific staining and labeling, P.multocida capsule of serovar A was found to contain material of the polysaccharide nature . But the capsular structures of obtained from agar-grown and broth cultures were different . The capsular layer on the surface of cells grown in Hottinger's broth was found to be more pronounced.

Can J Vet Res, 1999 Jan, 63(1), 5 - 12
Mast cells of the bovine trachea: staining characteristics, dispersion techniques and response to secretagogues; Harris WH et al.; Sections of the lower trachea of cattle, fixed in either Carnoy's or formalin, were stained with toluidine blue, alcian blue, or alcian blue and safranin O to study the mast cell population . After toluidine blue staining, about twice as many cells in tissue fixed in Carnoy's contained dark blue granules compared with tissue fixed in formalin . In addition, for the first time in cattle, a population of cells containing red granules was identified after staining with alcian blue and safranin O . Most of these red granules were formalin sensitive . An enzymatic dispersal technique for mast cells is described that yielded 9.4+/-0.4% mast cells (percentage of nucleated cells) with a viability of 92.3+/-0.6% . Spontaneous histamine release was 3.3+/-0.8% . Dispersed mast cells were challenged with various immunological and nonimmunological secretagogues . The calcium ionophores, A23187, ionomyocin, and BrX537A, were effective in releasing up to 94% of histamine in mast cells in a dose-response relationship . Pasteurella haemolytica culture supernate caused about 10% histamine release at a dose of 0.5 mg/mL after correction for spontaneous release . The average histamine content of the mast cells was 6.6+/-1.0 pg/cell . Cytospins of dispersed cells fixed in Carnoy's and stained with alcian blue and safranin O contained mast cells with blue and red granules, and a few cells with a mixture of both granule types . Based on the effects of type of fixation, staining characteristics and histamine content, a mix of subtypes of mast cells is present in the bovine trachea . However, functionally they respond to secretagogues differently than rodent mast cells . Without an immunological secretagogue, studies to determine compounds that will be effective in blocking mast cell degranulation will be limited.

Infect Immun, 1999 Feb, 67(2), 659 - 63
Induction of CD18-mediated passage of neutrophils by Pasteurella haemolytica in pulmonary bronchi and bronchioles; Ackermann MR et al.; Pasteurella haemolytica is an important respiratory pathogen of cattle that incites extensive infiltrates of neutrophils into the lung . In addition to the parenchymal damage caused by factors released by P . haemolytica, neutrophils contribute to the pathologic changes in the lungs . Molecules which mediate neutrophil infiltration into the lungs during P . haemolytica pneumonia are poorly characterized . To determine whether the CD18 family (beta2-integrin) of leukocyte adhesion molecules mediates initial passage of neutrophils into the pulmonary bronchi and bronchioles of lungs infected with P . haemolytica, three Holstein calves homozygous for bovine leukocyte adhesion deficiency (BLAD) (CD18-deficient neutrophils), and three age- and breed-matched control calves (normal CD18 expression) were inoculated with P . haemolytica A1 via a fiberoptic bronchoscope and euthanized at 2 h postinoculation . Sections of lung were stained for neutrophils, and the intensity of neutrophilic infiltration was determined by computerized image analysis . Significantly fewer (P < 0.05) neutrophils infiltrated the lumen, epithelium, and adventitia of bronchioles and bronchi in lungs of calves with BLAD compared to normal calves, which had dense infiltrates within these sites at 2 h postinoculation . The reduced infiltration in calves with BLAD occurred despite the presence of an extremely large number of neutrophils in peripheral blood that is typical for these calves . The large number of neutrophils in the blood of calves with BLAD is probably a physiologic response that can occur without microbial colonization, since one calf with BLAD that was raised under germ-free conditions had large numbers of neutrophils in the blood that were similar to those in a calf with BLAD that was raised conventionally . Neutrophil counts in the germ-free and conventionally reared calves with BLAD were much higher than those in the three normal calves raised under germ-free conditions . The work in this study demonstrates that during the initial inflammatory response, neutrophils with normal CD18 expression pass more readily than CD18-deficient neutrophils into the walls and lumen of bronchi and bronchioles . It suggests that CD18 is needed for initial passage through the extensive extracellular matrix of the bronchi and bronchioles . This has potential importance for the development of therapies to direct or inhibit neutrophil infiltration into conducting airways rather than alveolar spaces.

Microb Pathog, 1998 Dec, 25(6), 317 - 31
Molecular and biochemical mechanisms of Pasteurella haemolytica leukotoxin-induced cell death; Wang JF et al.; Pasteurella haemolytica leukotoxin (LKT) is a member of the RTX family of pore-forming toxins that kill bovine immune cells . Several studies have suggested that RTX toxins kill target cells by the induction of apoptosis . In the present study, BL3 bovine leukaemia cells were exposed to LKT and assessed by molecular and flow cytometric techniques that measure different aspects of apoptotic cell death . The intoxicated cells demonstrated morphological, light scatter and Hoechst 33258 staining characteristics consistent with cells undergoing apoptosis . The cells also exhibited internucleosomal DNA fragmentation and poly (ADP-ribose) polymerase (PARP) cleavage, both indicators of apoptosis . LKT-treated cells bound annexin-V-FITC indicating that phosphatidylserine groups were translocated from the inner to the outer leaflet of the cell membrane . The effect of LKT on cells was dose dependent and inhibitable by incubation with anti-LKT monoclonal antibody . Finally, an early step for induction of apoptosis appears to be the binding of LKT to a beta2 integrin since pre-incubating cells with anti-beta2 integrin antibodies inhibited LKT-induced apoptosis . This study provides new insights into understanding the pathogenesis of bovine pasteurellosis and could lead to the development of both preventative and therapeutic strategies for disease management .

J Clin Microbiol, 1999 Feb, 37(2), 380 - 5
Pulsed-field gel electrophoresis is more efficient than ribotyping and random amplified polymorphic DNA analysis in discrimination of Pasteurella haemolytica strains; Kodjo A et al.; One hundred thirty-three strains of Pasteurella haemolytica of both biotypes (90 and 43 strains of biotypes A and T, respectively) and almost all the serotypes were subjected to ribotyping, random amplified polymorphic DNA (RAPD) analysis, and pulsed-field gel electrophoresis (PFGE) analysis for epidemiological purposes . A total of 15 patterns recorded as ribotypes HA to HO were found for the P . haemolytica biotype A strains, with ribotypes HA, HC, and HD being encountered most often (66 strains {74%}); and 20 ribotypes, designated HA' to HT', that were clearly distinct from those observed for biotype A strains were observed for strains of biotype T . RAPD analysis generated a total of 44 (designated Rp1 to Rp44) and 15 (designated Rp1' to Rp 15') unique RAPD patterns for biogroup A and biogroup T, respectively . Analysis of the data indicated that a given combined ribotype-RAPD pattern could be observed for biotype A strains of different serotypes, whatever the zoological or geographic origin, whereas this was not the case for biotype T strains . PFGE appeared to be more efficient in strain discrimination since selected strains from various zoological or geographical origins harboring the same ribotype-RAPD group were further separated into unique entities.

Berl Munch Tierarztl Wochenschr, 1998 Nov-Dec, 111(11-12), 422 - 6
{Resistance of bovine and porcine Pasteurella to florfenicol and other antibiotics}; Hormansdorfer S et al.; The resistance pattern of 221 (89 bovine, 132 porcine) pasteurella strains isolated in 1996 against 16 antibiotics or chemotherapeutics was determined by agar diffusion . Pasteurella haemolytica showed a higher level of resistance compared to Pasteurella multocida; porcine strains were more resistant than bovine strains . Over 90% of porcine Pasteurella multocida were sensible to penicillin G, ampicillin, cephalothin, polymyxin B, enrofloxacin, chloramphenicol and florfenicol . In addition, bovine strains were at least 90% sensible to oxacillin, erythromycin, gentamycin and sulfmethoxazole-trimethoprim . More than 90% of porcine Pasteurella haemolytica were classified as sensible to polymyxin B, enrofloxacin und florfenicol; bovine strains to cephalothin, neomycin und chloramphenicol as well . In 1996, 2 years after the chloramphenicol ban for food rendering animals, only 6.3% of bovine pasteurella strains proved to be resistant against chloramphenicol compared to a 16.27% fraction in 1994 . The mean MIC-values of florfenicol against pasteurella spp . were nearly the same in bovine and porcine isolates with 0.53 microgram/ml and 0.52 microgram/ml respectively . Pasteurella haemolytica, however, showed higher MIC-values (0.68 microgram/ml in bovine, 0.70 microgram/ml in porcine isolates) than Pasteurella multocida with 0.47 microgram/ml in bovine and 0.51 microgram/ml in porcine strains . No isolate had a MIC of florfenicol greater than 1.0 microgram/ml, all pasteurella strains were classified sensible to florfenicol.

Vet Immunol Immunopathol, 1998 Dec 11, 66(3-4), 391 - 404
Role of Pasteurella multocida porin on cytokine expression and release by murine splenocytes; Iovane G et al.; The aim of this study was to verify whether Pasteurella multocida porin can affect the expression and release of IL-1alpha, IL-6, TNF-alpha, IL-4, IFN-gamma, IL-10 and IL-12 by murine splenocytes in vitro . P . multocida porin and lipopolysaccharide (LPS) were able to induce the release of IL-1alpha, IL-6, TNF-alpha, IFN-gamma and IL-12 in a dose-dependent fashion . The greatest release of these cytokines was obtained using P . multocida porin at a concentration of 5 microg ml(-1) and LPS at a concentration of 1 microg ml(-1) . The time-courses of release showed that P . multocida LPS was able to stimulate the production of IL-1alpha, IL-6, TNF-alpha, IFN-gamma and IL-12 earlier than porin and at a greater rate . No effect was observed on IL-4 and IL-10 release under the same experimental conditions . P . multocida porin and LPS were also able to up-regulate the mRNA expression of IL-1alpha, IL-6, TNF-alpha, IFN-gamma and IL-12 p40 . Our findings suggest that P . multocida porin is able to modulate inflammatory and immunological responses by affecting the release of several cytokines and the expression of their genes.

J Med Microbiol, 1998 Aug, 47(8), 679 - 88
Demonstration that Australian Pasteurella multocida isolates from sporadic outbreaks of porcine pneumonia are non-toxigenic (toxA-) and display heterogeneous DNA restriction endonuclease profiles compared with toxigenic isolates from herds with progressive atrophic rhinitis; Djordjevic SP et al.; Capsular types A and D of Pasteurella multocida cause economic losses in swine because of their association with progressive atrophic rhinitis (PAR) and enzootic pneumonia . There have been no studies comparing whole-cell DNA profiles of isolates associated with these two porcine respiratory diseases . Twenty-two isolates of P . multocida from diseased pigs in different geographic localities within Australia were characterised genotypically by restriction endonuclease analysis (REA) with the enzyme CfoI . Seven of 12 P . multocida isolates from nasal swabs from pigs in herds where PAR was either present or suspected displayed a capsular type D phenotype . These were shown to possess the toxA gene by polymerase chain reaction (PCR) and Southern hybridisation, and further substantiated by production of cytotoxin in vitro . The CfoI profile of one of these seven isolates, which was from the initial outbreak of PAR in Australia (in Western Australia, WA), was identical with profiles of all six other toxigenic isolates from sporadic episodes in New South Wales (NSW) . The evidence suggests that the strain involved in the initial outbreak was responsible for the spread of PAR to the eastern states of Australia . Another 10 isolates, representing both capsular types A and D, were isolated exclusively from porcine lung lesions after sporadic outbreaks of enzootic pneumonia in NSW and WA . CfoI restriction endonuclease profiles of these isolates revealed considerable genomic heterogeneity . Furthermore, none of these possessed the toxA gene . This suggests that P . multocida strains with the toxA gene do not have a competitive survival advantage in the lower respiratory tract or that toxin production does not play a role in the pathology of pneumonic lesions, or both . REA with polyacrylamide gel electrophoresis and silver staining was found to be a practical and discriminatory tool for epidemiological tracing of P . multocida outbreaks associated with PAR or pneumonia in pigs.

Avian Dis, 1998 Oct-Dec, 42(4), 770 - 80
Early pulmonary lesions in turkeys produced by nonviable Aspergillus fumigatus and/or Pasteurella multocida lipopolysaccharide; Kunkle RA et al.; This study assessed the potential of lipopolysaccharide (LPS) purified from Pasteurella multocida to cause pulmonary pathology or exacerbate lesions produced by gamma-irradiated nonviable Aspergillus fumigatus conidia when administered via the intra-air sac route in turkeys . LPS provoked suppurative airsacculitis, pleuritis, and pneumonia . Nonviable conidia produced airsacculitis and transient pneumonitis but did not elicit multinucleate giant cells, which are a feature of the inflammatory process in A . fumigatus infection . LPS in combination with A . fumigatus conidia resulted in accelerated pulmonary inflammation and apparently delayed clearance of conidia from pulmonary tissues . This study presents a model of aseptic airsacculitis and pneumonia with clinical relevance.

Avian Dis, 1998 Oct-Dec, 42(4), 752 - 6
Bacterin-induced protection of turkeys against fowl cholera following infection with Bordetella avium; Rimler RB et al.; Groups of Beltsville small white turkeys, passively immunized and not passively immunized against Bordetella avium, were challenged with live B . avium at 2 days of age . Birds not passively immunized developed severe bordetellosis with early onset, whereas passively immunized birds developed mild bordetellosis with late onset . Following convalescence, birds with and without exposure to B . avium were vaccinated against fowl cholera with a water-in-oil bacterin . The birds were given a homologous challenge with serotype A: 3 Pasteurella multocida . Although no difference in protection against fowl cholera was seen between vaccinated birds that were previously infected with B . avium and those that were not, survivability was better in birds given two doses rather than 1 dose of bacterin.

Vet Res Commun, 1998 Nov, 22(7), 445 - 55
Adaptive acquisition of novobiocin resistance in Pasteurella multocida strains of avian origin; Arif M et al.; Naturally occurring strains of Pasteurella multocida are atypically susceptible to hydrophobic antibiotics such as novobiocin, despite their Gram-negative cell envelope ultrastructure . Four strains adaptively resistant to 1000 micrograms/ml of novobiocin were obtained by sequentially subculturing cell surface hydrophobic variants of avian origin in the presence of increasing antibiotic concentrations . Adaptive novobiocin resistance was accompanied in all cases by the concomitant acquisition of resistance to coumermycin, a hydrophobic antibiotic possessing the same mechanism of action, but not to the functionally disparate hydrophobic antibiotic rifamycin . The acquisition of resistance was not accompanied by alterations in the lipid composition of the cell envelope . Subsequent growth of adaptively resistant strains in the absence of novobiocin did not result in the restoration of susceptibility to either novobiocin or coumermycin . Acquisition of adaptive resistance in encapsulated parental strains resulted in an inability to synthesize capsular material and enhanced cell surface hydrophobicity; however, parental encapsulation and decreased cell surface hydrophobicity were restored upon removal of novobiocin . These data suggest that acquisition of adaptive resistance to novobiocin conferred in this manner is the result of a stable genetic event affecting the mechanistic target of both novobiocin and coumermycin rather than a physiological adaptation involving outer membrane impermeability.

Infect Immun, 1999 Jan, 67(1), 80 - 7
Localization of the intracellular activity domain of Pasteurella multocida toxin to the N terminus; Wilson BA et al.; We have shown that Pasteurella multocida toxin (PMT) directly causes transient activation of Gqalpha protein that is coupled to phosphatidylinositol-specific phospholipase Cbeta1 in Xenopus oocytes (B . A . Wilson, X . Zhu, M . Ho, and L . Lu, J . Biol . Chem . 272:1268-1275, 1997) . We found that antibodies directed against an N-terminal peptide of PMT inhibited the toxin-induced response in Xenopus oocytes, but antibodies against a C-terminal peptide did not . To test whether the intracellular activity domain of PMT is localized to the N terminus, we conducted a deletion mutational analysis of the PMT protein, using the Xenopus oocyte system as a means of screening for toxin activity . Using PCR and conventional cloning techniques, we cloned from a toxinogenic strain of P . multocida the entire toxA gene, encoding the 1,285-amino-acid PMT protein, and expressed the recombinant toxin as a His-tagged fusion protein in Escherichia coli . We subsequently generated a series of N-terminal and C-terminal deletion mutants and expressed the His-tagged PMT fragments in E . coli . These proteins were screened for cytotoxic activity on cultured Vero cells and for intracellular activity in the Xenopus oocyte system . Only the full-length protein without the His tag exhibited activity on Vero cells . The full-length PMT and N-terminal fragments containing the first 500 residues elicited responses in oocytes, but the C-terminal 780 amino acid fragment did not . Our results confirm that the intracellular activity domain of PMT is localized to the N-terminal 500 amino acids of the protein and that the C terminus is required for entry into cells.

FEMS Microbiol Lett, 1998 Dec 1, 169(1), 139 - 45
Target cell specificity of the Pasteurella haemolytica leukotoxin is unaffected by the nature of the fatty-acyl group used to activate the toxin in vitro; Hormozi K et al.; The leukotoxin (LktA) of Pasteurella haemolytica is active only against cells of ruminant origin . It is synthesised as an inactive protoxin encoded by the lktA gene and post-translationally modified to the active toxin by the product of the lktC gene . The LktA and LktC proteins were expressed separately in Escherichia coli and partially purified . Active LktA was produced in vitro in the presence of LktC and acyl-acyl carrier protein (ACP) charged separately in vitro with a fatty-acyl group . The toxic activity and target cell specificity of LktA and adenylate cyclase toxin (CyaA), a toxin active against a wide variety of mammalian cells, were investigated after activation with ACP charged with different fatty acids . Palmitoyl-ACP produced the most active toxin in both cases and, although other fatty acids were also effective, the fatty acid preference was the same for the in vitro activation of both toxins . Activated LktA remained ruminant cell-specific whichever acyl group was used to acylate the A protoxin.

Vet Microbiol, 1998 Oct, 63(2-4), 205 - 15
Acute septicaemic pasteurellosis in Vietnamese pigs; Townsend KM et al.; Sixteen isolates of Pasteurella multocida were cultured from cases diagnosed as acute septicaemic pasteurellosis in Vietnamese pigs . The HSB-PCR assay provided rapid presumptive determination of 10 isolates of P . multocida identified as haemorrhagic septicaemia (HS) causing type B cultures (B:2, B:5, B:2,5) . Serological designation using the Carter and Heddleston typing systems confirmed these findings, and identified the six HSB-PCR negative cultures as either A:1, A:3 or D:3,4 . Biochemical fermentation and REP-PCR revealed phenotypic and genotypic identity between P . multocida type A:1 isolated from Vietnamese pigs and poultry . Marked homogeneity was also demonstrated among HSB-PCR positive swine isolates, which were shown to possess genotypic identity with P . multocida type B:2 from buffaloes diagnosed with HS.

Onderstepoort J Vet Res, 1998 Jun, 65(2), 105 - 12
The clinical efficacy of enrofloxacin in the treatment of experimental bovine pneumonic pasteurellosis; Thompson PN et al.; The clinical efficacy of enrofloxacin was tested in calves with experimentally induced pneumonic pasteurellosis . A strain of Pasteurella haemolytica, biotype A, serotype 1 (P . haemolytica A1), which had been isolated from an outbreak of pneumonic pasteurellosis in feedlot calves, was used to induce the disease in 24 eight-month-old calves . Each animal received, by intratracheal injection, 6 x 10(11) colony forming units of P . haemolytica A1 in a four-hour log phase culture . Twelve similar animals were kept as non-infected controls (Negative Control group) . Treatment of the infected animals commenced 40 h after infection and was as follows: 12 animals each received 2.5 mg/kg enrofloxacin subcutaneously and 12 animals each received 5 ml sterile saline intramuscularly (Positive Control group) . All treatments were given once daily for three consecutive days . Clinical examinations were performed on all animals once daily, starting prior to infection and continuing until 12 d post-infection . The parameters evaluated were rectal temperature, habitus (attitude), ocular mucous membrane congestion and abnormal sounds on lung auscultation . On day 14 post-infection, all animals were killed and their lung lesions (if any) estimated as the percentage involvement of each pair of lungs . The only statistically significant (P > or = 0.05) differences observed were between the Negative Control group and the Positive Control group . Noticeable differences were seen between the enrofloxacin-treated group and the Positive Control group, but they were not statistically significant (P > 0.05) . The average lung lesion score (pneumonic lesions as a percentage of total lung volume) for the Positive Control group was 12.1% and that of the enrofloxacin-treated group, 8.4% . This difference was not statistically significant (P > 0.05).

Curr Microbiol, 1999 Jan, 38(1), 64 - 7
Secretion of proteases from Pasteurella multocida isolates; Negrete-Abascal E et al.; The capability of Pasteurella multocida to secrete proteases to the culture medium and their characterization were studied in five animal isolates (bovine, chicken, sheep, and two from pig) . All the isolates produced proteases in a wide range of molecular mass . It is suggested that they are neutral metalloproteases, since they were optimally active between pH 6 and 7, inhibited by chelating agents but not by other protease inhibitors, and reactivated by calcium . Proteases from isolates were able to degrade IgG . Several proteins from supernatants of cultures precipitated with 70% (NH4)2SO4 of all the P . multocida isolates were recognized by a polyclonal antiserum raised against a purified protease from Actinobacillus pleuropneumoniae . Protease production might play an important role during tissue colonization and in P . multocida diseases.

Biochim Biophys Acta, 1998 Nov 26, 1443(1-2), 262 - 6
A new tetracycline resistance determinant cloned from Proteus mirabilis; Magalhaes VD et al.; The chromosomal inducible Tcr determinant from Proteus mirabilis was cloned and the nucleotide sequence of both the structural and repressor genes determined . The deduced amino acid sequence of the structural protein shows the highest similarity to TetA(H) from Pasteurella multocida (78.4%), followed by TetA(B) from Tn10 (50.9%) . Based on this analysis, we suggest that this new determinant can be assigned to a new class, TetJ.

Int J Syst Bacteriol, 1998 Oct, 48 Pt 4, 1145 - 51
Phenotypic characterization of the marine pathogen Photobacterium damselae subsp . piscicida; Thyssen A et al.; The taxonomic position of Photobacterium damselae subsp . piscicida, the causative agent of fish pasteurellosis, is controversial as this organism has also been described as 'Pasteurella piscicida' . To clarify the taxonomic position of the pathogen, a total of 113 P . damselae subsp . piscicida strains and 20 P . damselae subsp . damselae strains, isolated from different geographical areas and from the main affected fish species, were analysed using 129 morphological and biochemical tests, including the commercial API 20E and API CH50 test systems . For comparison, the type strains of other Photobacterium species (i.e . Photobacterium leiognathi and Photobacterium angustum) were included in the analyses . The results were statistically analysed by unweighted pair group average clustering and the distance between the different clusters was expressed as the percentage disagreement . The analyses showed that, based on morphological and biochemical identification tests, P . damselae subsp . piscicida is related to other Photobacterium species . However, it is clearly distinguishable from P . damselae subsp . damselae and no phenotypic evidence was found to include P . damselae subsp . piscicida as a subspecies in the species P . damselae.

Infect Immun, 1998 Dec, 66(12), 5636 - 42
Activity of the mitogenic Pasteurella multocida toxin requires an essential C-terminal residue; Ward PN et al.; Pasteurella multocida toxin (PMT) is a potent mitogen that also affects bone resorption . PMT acts intracellularly and is therefore postulated to have several domains involved in different aspects of its function . The toxin contains eight cysteine residues . Mutants with individual substitutions for each of these residues were constructed, and the effects of these on the biological activity of the toxin were determined by cultured-cell assays . Only the most C-terminal of the eight cysteines (C1165) was essential for full activity, although mutation of the cysteine residue at position 1159 caused a slight but reproducible loss of potency . In animal challenge experiments, mutant toxin (C1165S) was not toxic to piglets, even at doses exceeding a lethal dose of active PMT 1, 000-fold . The mutant and wild-type toxins displayed identical purification characteristics, similar susceptibility to proteolytic digestion, and circular dichroism profiles, which indicated that no gross structural changes had taken place . The function of the essential C1165 residue is not yet known, although its most likely role is an enzymatic one at or near the catalytic center of the toxin.

Infect Immun, 1998 Dec, 66(12), 5613 - 9
Genetic and immunologic analyses of PlpE, a lipoprotein important in complement-mediated killing of Pasteurella haemolytica serotype 1; Pandher K et al.; Pasteurella haemolytica serotype 1 is the bacterium most commonly associated with bovine shipping fever . The presence of antibodies against P . haemolytica outer membrane proteins (OMPs) correlates statistically with resistance to experimental P . haemolytica challenge in cattle . Until now, specific P . haemolytica OMPs which elicit antibodies that function in host defense mechanisms have not been identified . In this study, we have cloned and sequenced the gene encoding one such protein, PlpE . Analysis of the deduced amino acid sequence revealed that PlpE is a lipoprotein and that it is similar to an Actinobacillus pleuropneumoniae lipoprotein, OmlA . Affinity-purified, anti-PlpE antibodies recognize a protein in all serotypes of P . haemolytica except serotype 11 . We found that intact P . haemolytica and recombinant E . coli expressing PlpE are capable of absorbing anti-PlpE antibodies from bovine immune serum, indicating that PlpE is surface exposed in P . haemolytica and assumes a similar surface-exposed conformation in E . coli . In complement-mediated killing assays, we observed a significant reduction in killing of P . haemolytica when bovine immune serum that was depleted of anti-PlpE antibodies was used as the source of antibody . Our data suggest that PlpE is surface exposed and immunogenic in cattle and that antibodies against PlpE contribute to host defense against P . haemolytica.

J Appl Microbiol, 1998 Oct, 85(4), 746 - 54
Degradation of fluoranthene by Pasteurella sp . IFA and Mycobacterium sp . PYR-1:isolation and identification of metabolites; Sepic E et al.; The findings from a biodegradability study of fluoranthene using two pure bacterial strains, Pasteurella sp . IFA (B-2) and Mycobacterium sp . PYR-1 (AM) are reported . Of total fluoranthene, 24% (B-2) and 46% (AM) was biodegraded in an aqueous medium during 14 d of incubation at room temperature . During this period the bacteria were capable of mineralizing approximately two-thirds (B-2) and four-fifths (AM) of biodegraded fluoranthene to CO2, while one-third (B-2) and one-fifth (AM) of the original fluoranthene remained as stable metabolic products . These metabolites were isolated using liquid-liquid extraction and identified using gas chromatography-mass spectrometry (GC-MS) and derivatization techniques . Two metabolites (9-fluorenone-1-carboxylic acid and 9-fluorenone) were identified by GC-MS directly, while the metabolites 9-fluorenone-1-carboxylic acid, 9-hydroxyfluorene, 9-hydroxy-1-fluorene-carboxylic acid, 2-carboxybenzaldehyde, benzoic acid and phenylacetic acid were determined in their derivatized forms . From the identified metabolites, a fluoranthene biodegradation pathway was proposed for Pasteurella sp . IFA.

J Bacteriol, 1998 Nov, 180(22), 6054 - 8
Physical and genetic map of the Pasteurella multocida A:1 chromosome; Hunt ML et al.; A physical and genetic map of the Pasteurella multocida A:1 genome was generated by using the restriction enzymes ApaI, CeuI, and NotI . The positions of 23 restriction sites and 32 genes, including 5 rrn operons, were localized on the 2.35-Mbp single circular chromosome . This report presents the first genetic and physical map for this genus.

Zentralbl Bakteriol, 1995 Nov, 283(1), 105 - 14
Occurrence of sialidase and N-acetylneuraminate lyase in Pasteurella species; Muller HE et al.; Pasteurella species and related taxa are opportunistic pathogens parasitizing on mucous membranes of higher organisms containing sialic acids . Therefore, sialidase is a virulence factor which up to now has been described to be present in P . haemolytica, P . multocida, and P . volantium . Because of some taxonomic changes and the description of many new species or still unnamed groups, the presence of sialidase and the metabolic successor enzyme, N-acetylneuraminate lyase, was investigated in 65 Pasteurella or Pasteurella-like strains . The detection of enzymes was performed by colorimetry, by paper chromatography and immunoelectrophoresis . Using bovine submaxillary mucin as substrate, sialidases were produced in all strains studied although the activities were different . Most strains but not all were positive in N-acetylneuraminate lyase, too . Taken together, the strains of Pasteurella sensu stricto showed the strongest activities of sialidase, those of the Pasteurella aerogenes complex the lowest . However, because of loss of sialidase activity during subcultivation, there is little feasibility to characterize Pasteurella species by these enzymes.

Br Poult Sci, 1998 Sep, 39(4), 492 - 6
Pharmacokinetics of florfenicol in normal and Pasteurella-infected Muscovy ducks; el-Banna HA; 1 . Disposition kinetics of florfenicol were studied in Pasteurella-free (control) and Pasturella-infected Muscovy ducks following intravenous and/or intramuscular injection in a single dose of 30 mg/kg body weight . In addition, the tissue distribution and residual pattern of the drug were determined in diseased ducks . 2 . The maximum serum concentration of florfenicol in control healthy and infected ducks was reached 1 hour after intramuscular injection but the peak concentration in control ducks was higher than in infected birds . 3 . The volume of distribution, total body clearance and systemic bioavailability were higher in infected ducks than in control birds 5.15 l/kg, 10.24 ml/kg/min and 73.03% respectively . Data relating to intravenous injection were analysed using a 2 compartment open model curve fit . 4 . Florfenicol was not detected in the serum of infected ducks on the 7th day following intramuscular administration of 30 mg/kg body weight twice daily for 5 successive days but was detected in kidney, bile and liver.

Vaccine, 1998 Dec, 16(20), 2018 - 25
Serologic responses of young colostrum fed dairy calves to antigens of Pasteurella haemolytica A1; Hodgins DC et al.; The potential and limitations of early calfhood vaccination to induce active immunity to Pasteurella haemolytica A1 in conventional colostrum fed calves were investigated . Holstein dairy calves (n = 29) were vaccinated at 2 and 4 weeks of age, or at 6 and 8 weeks of age with a commercial culture supernatant vaccine (Presponse, Langford Inc., Guelph, Ont., Canada), or remained unvaccinated as controls . Serum antibody titres were measured using an indirect bacterial agglutination assay, a leukotoxin neutralization assay, and enzyme immunoassays for antibodies of the IgM, IgG1, and IgG2 isotypes binding purified capsular polysaccharide of P . haemolytica A1 . Seroconversion (fourfold or greater increase in serum antibody titre) rates were compared using Fisher's exact test . The effects of passive antibody titres and age on response to vaccination were assessed by linear modelling . Vaccination at 2 and 4 weeks of age was associated with 40%, and 0% of calves seroconverting on the basis of agglutinating antibody titres, and leukotoxin neutralizing titres respectively, and 50%, 0%, and 0% seroconverting on the basis of IgM, IgG1 and IgG2 antibodies to capsular polysaccharide, respectively . Agglutinating antibody responses were not related to prevaccination antibody titres, or to age at vaccination . Higher responses (p = 0.08) to leukotoxin were observed in older calves (after taking differences in prevaccination titres into account) . Statistical analyses of responses to capsular polysaccharide among calves with comparable prevaccination IgG1 antibody titres revealed significantly higher IgM, IgG1 and IgG2 responses in older calves . Rising titres of IgM antibodies in nonvaccinated calves after 5 weeks of age suggest natural exposure to P . haemolytica A1 or antigens which result in serologic cross-reactions as a means of priming immune responses.

Vaccine, 1998 Dec, 16(20), 1962 - 70
Duration of serum antibody responses following vaccination and revaccination of cattle with non-living commercial Pasteurella haemolytica vaccines; Confer AW et al.; This study was designed to determine the duration of serum antibody responses to Pasteurella haemolytica whole cells (WC) and leukotoxin (LKT) in weanling beef cattle vaccinated with various non-living P . haemolytica vaccines . Serum antibodies to P . haemolytica antigens were determined periodically through day 140 by enzyme-linked immunosorbent assays . At day 140, cattle were revaccinated, and antibody responses periodically determined through day 196 . Three vaccines were used in two experiments (A and B), OneShot, Presponse HP/tK, and Septimune PH-K . In general, all three vaccines between 7 and 14 days induced antibody responses to WC after vaccination . Antibodies to LKT were induced with OneShot and Presponse . Revaccination at days 28 and 140 usually stimulated anamnestic responses . Serum antibodies to the various antigens remained significantly increased for up to 84 days after vaccination or revaccination . The intensity and duration of antibody responses were variable depending on the experiment and vaccines used . Vaccination with OneShot usually stimulated the greatest responses to WC . Vaccination with OneShot or Presponse resulted in equivalent primary anti-LKT responses . In experiment B, spontaneous seroconversion was found in numerous calves on day 112 . Revaccination of those cattle at day 140 resulted in markedly variable antibody responses such that several groups had no increase in antibody responses.

J Vet Med Sci, 1998 Sep, 60(9), 1021 - 3
Histochemical and lectinhistochemical studies on nasal mucosa of pigs with or without respiratory diseases; Perfumo CJ et al.; Histochemical and lectinhistochemical examinations were carried out on nasal mucosa of pigs with or without respiratory diseases . As the results, both acid and neutral mucins coexisted in nasal mucosa of normal pigs while acid sialomucins were mainly observed in nasal mucosa of pigs infected with Bordetella bronchiseptica and/or Pasteurella multocida . Lectinhistochemistry revealed that the nasal epithelial cells of normal pigs were rich in N-acetylgalactosamine, fucose and N-acetyl-glucosamine residues which showed a tendency to disappear in porcine cytomegalovirus infection and to increase in atrophic rhinitis, respectively.

Scand J Infect Dis, 1998, 30(3), 313 - 4
Pasteurella multocida pneumonia with empyema; Ory JM et al.; We report a case of Pasteurella multocida pneumonia and empyema in an otherwise healthy patient . The most frequently observed human complication with this microorganism is a local wound infection . Only a few cases of pneumonia have been described, and most of the patients were immunodeficient.

Vet Rec, 1998 Sep 5, 143(10), 277 - 9
Actinobacillus and Pasteurella species isolated from horses with lower airway disease; Ward CL et al.; Seventy-three bacterial isolates from 65 horses with and without evidence of lower airway disease were identified to assess whether the association with disease was accounted for by a small or large number of species . Just over half (50.5 per cent were Actinobacillus equuli, 17.8 per cent were A suis-like, 11 per cent were Pasteurella pneumotropica, 8.2 per cent were A lignieresii, 6.8 per cent were P haemolytica and 5.5 per cent were P mairii . These results suggest that a range of Actinobacillus and Pasteurella species can be isolated from the lower airways of horses, with many of the isolates being A equuli . Among the horses examined, lower airway inflammation was significantly associated with A suis-like bacteria and A lignieresii . However, these two species constituted too small a proportion of the undifferentiated Actinobacillus/Pasteurella species to explain the association of this group of bacteria with lower airway disease . Since A equuli constituted just over 50 per cent of the group of bacteria it is possible that it too is playing a significant role in lower airway disease.

Vet Rec, 1998 Sep 5, 143(10), 269 - 72
Efficacy of doxycycline in feed for the control of pneumonia caused by Pasteurella multocida and Mycoplasma hyopneumoniae in fattening pigs; Bousquet E et al.; A multicentre, controlled, randomised and blinded study was carried out in three French pig herds to assess the efficacy of doxycycline administered in the feed for the control of pneumonia . About 20 per cent of 363 pigs from the three fattening units were diseased at the start of the study . Pneumonic lesions were found on pigs examined postmortem and Pasteurella multocida was isolated from the lungs of pigs in all the herds . Mycoplasma hyopneumoniae infection was confirmed either by detection in pneumonic lungs or by seroconversion in pigs sampled three weeks apart . P multocida, Bordetella bronchiseptica and Actinobacillus pleuropneumoniae were isolated from 64 per cent, 50 per cent and 2 per cent, respectively, of 148 nasal swabs . The following variables were significantly different between the treated and untreated groups (P < or = 0.001): the incidence of diseased pigs during the three weeks from the start of treatment (8.1 per cent in treated group v 35.4 per cent in control group), mean daily weight gain over the same period (934 g/day in the treated group v 834 g/day in the control group) and the cure rate of pigs which were diseased at the start of treatment (73.5 per cent in treated group v 35.3 per cent in control group) . These data demonstrate that an average dose of 11 mg doxycycline/kg bodyweight per day in feed for eight days was effective in controlling pneumonia due to P multocida and M hyopneumoniae in these fattening pigs.

Am J Vet Res, 1998 Oct, 59(10), 1275 - 80
Characterization of a Pasteurella haemolytica A1 mutant deficient in production of three membrane lipoproteins; Murphy GL et al.; OBJECTIVE: To determine whether a Pasteurella haemolytica A1 mutant that is unable to produce membrane lipoproteins has reduced susceptibility to complement-mediated killing, and to characterize the mutant strain . SAMPLE POPULATION: 12 sera from cattle resistant to P haemolytica challenge exposure after vaccination with P haemolytica or its antigens, or after natural exposure . PROCEDURES: Complement-mediated killing assays were performed, using wild-type and mutant strains and, as antibody source, various immune sera from cattle that were resistant to P haemolytica challenge exposure . Antibody response to whole-cell antigens produced by mutant and wild-type strains, production of outer membrane proteins and iron-regulated outer membrane proteins by the 2 strains, and growth of the 2 strains in various media were analyzed . RESULTS: Compared with wild-type P haemolytica, the lipoprotein mutant strain had increased susceptibility to bovine complement-mediated killing . Aside from the lipoproteins that are not produced by the mutant, immunoblot analysis did not reveal differences between immunoreactive antigens that are produced by the 2 strains . Some iron-regulated, outer membrane proteins, which usually are only produced by P haemolytica under iron-deficient conditions, were produced constitutively by the mutant . The mutant grew to a lower final cell density and at a lower rate under conditions likely to reflect those encountered in vivo . CONCLUSIONS: Lack of 3 membrane lipoproteins resulted in enhanced susceptibility to bovine complement-mediated killing . Site-specific mutagenesis of genes encoding P haemolytica membrane lipoproteins alters production of iron-regulated outer membrane proteins by P haemolytica . Growth characteristics of the mutant suggested that it may have reduced capacity for survival in vivo.

Am J Vet Res, 1998 Oct, 59(10), 1270 - 4
Effects of the major Pasteurella multocida porin on bovine neutrophils; Galdiero M et al.; OBJECTIVE: To evaluate in vitro effect of the major fraction of outer membrane proteins of Pasteurella multocida with porin-like activities on some biological functions of bovine neutrophils . ANIMALS: Neutrophils from 5 adult cattle . PROCEDURE: Variations in such biological processes as actin polymerization and chemotaxis and evaluation of hydrogen peroxide attributable to variable concentrations of P multocida were recorded and compared . Data were obtained, using the porin and lipopolysaccharide (LPS) isolated from a strain of P multocida cultivated in brain-heart infusion (BHI) broth . Various concentrations of porin and LPS were analyzed to evaluate changes in functional activation and microbicidal activity of bovine neutrophils . RESULTS: The 37.5-kd major polypeptide of the outer membrane of P multocida was isolated . Presence of this porin was significantly correlated with variations of some biological functions of bovine neutrophils . These immunocompetent cells had a concentration-dependent increase in actin polymerization and chemotactic activity . A concentration-dependent variation in the oxidative burst also was observed . CONCLUSIONS: The porins of gram-negative bacteria affect several biological functions of cells involved in the immune response as well as in inflammation . Significant correlation of results of in vitro experiments also was identified between porin and LPS effect . Pretreatment of bovine neutrophils with various concentrations of porin always caused a concentration-dependent increase in examined biological activities.

Avian Dis, 1998 Jul-Sep, 42(3), 452 - 61
Postmortem detection of acute septicemia in broilers; Fisher ME et al.; Septicemia is an unwholesome condition diagnosed during postmortem inspection in poultry slaughter establishments on the basis of macroscopic lesions . Early identification of septicemia has important public health implications . In this study, Pasteurella multocida, Escherichia coli, and Staphylococcus aureus septicemia were induced in broilers in order to determine if lesions of acute septicemia can be grossly detected in the visceral organs of broiler carcasses prior to the development of changes in the skeletal muscle . Increased spleen and liver weights were observed during the acute phase of septicemia . Airsacculitis, pericarditis, and perihepatitis were observed during the acute phase of P . multocida- and E . coli-induced septicemia; and arthritis was the earliest indicator of S . aureus-induced septicemia . These macroscopic lesions were sufficient to identify unwholesome septicemic broiler carcasses prior to the development of changes in the skeletal muscle of the carcass.

Poult Sci, 1998 Oct, 77(10), 1510 - 21
Intracellular accumulation, subcellular distribution, and efflux of tilmicosin in chicken phagocytes; Scorneaux B et al.; Tilmicosin is a semi-synthetic macrolide antibiotic, currently approved for veterinary use in cattle and swine respiratory disease, and is in development for use in poultry mycoplasma air sacculitis . In order to provide an understanding of clinical efficacy, the in vitro interaction of tilmicosin with three types of chicken phagocytes (MQ-NCSU macrophages, monocyte-macrophages, and heterophils) was evaluated . After incubation with radiolabeled tilmicosin, uptake was determined and expressed as the ratio of the cellular (Cc) to the extracellular (Ce) drug concentration (Cc:Ce) . Tilmicosin was avidly accumulated by heterophils (Cc: Ce 138 at 4 h incubation vs 32 and 66, respectively, in MQ-NCSU and monocyte-macrophages) with 61 to 88% localized in the lysosomes . Uptake was dependent on cell viability, temperature, and pH, but was not influenced by metabolic inhibitors . However, phagocytosis of Pasteurella multocida and lipopolysaccharide exposure increased tilmicosin uptake by the chicken phagocytes . Upon removal of extracellular tilmicosin, 50% of the intracellular tilmicosin was effluxed within the first 30 min, but after 4 h of incubation in antibiotic-free medium, 30% remained cell-associated . Opsonized P . multocida significantly enhanced the release of tilmicosin from all three types of chicken phagocytes . Tilmicosin uptake was observed to increase lysosomal enzyme (acid phosphatase, lysozyme, avidin, and beta-glucuronidase) production . Finally, neutrophils were shown to transport and efflux bioactive tilmicosin in a test system measuring both neutrophil chemotaxis under agarose and a bioassay measuring inhibition of bacterial growth in the presence of antibiotic in agar . These in vitro observations of cellular pharmacology suggest a complex interaction between phagocytes and tilmicosin that contribute to clinical efficacy.

Comp Immunol Microbiol Infect Dis, 1998 Oct, 21(4), 257 - 79
Immunogenicity of purified lipopolysaccharide or protein-oligosaccharide conjugates of Pasteurella multocida type 6:B in mice; Muniandy N et al.; Purified lipopolysaccharide (LPS) of Pasteurella multocida type 6:B, while toxic at higher doses, was protective at lower dose levels against experimentally-induced pasteurellosis in mice . However, the observed protection was abrogated if such LPS was digested with proteinase K prior to use in immunisation . The O-antigen polysaccharide side-chain (OS) of LPS did not appear to contribute to the observed protection as judged by the fact that immunisation of mice with purified OS or OS-protein conjugates, all of which were nontoxic, failed to confer protection against challenge with homologous virulent organisms . This was despite generation of significant levels of OS-specific antibodies, predominantly either of the IgM or IgG isotypes, in immunised mice.

J Clin Microbiol, 1998 Nov, 36(11), 3342 - 6
Two-color hybridization assay for simultaneous detection of Bordetella bronchiseptica and toxigenic Pasteurella multocida from swine; Register KB et al.; Bordetella bronchiseptica and toxigenic Pasteurella multocida are the etiologic agents of swine atrophic rhinitis . Methods currently used for their identification are time-consuming and suffer from a lack of sensitivity . We describe a colony lift-hybridization assay for detection of B . bronchiseptica and toxigenic P . multocida that can be performed with a single colony lift derived from a primary isolation plate without the need for pure subcultures of suspect bacteria . Membranes are hybridized simultaneously to probes derived from the B . bronchiseptica alcA gene and the P . multocida toxA gene . A multicolor development procedure permits sequential detection of bound probes . The assay was tested with 84 primary isolation plates generated from nasal swabs from swine with clinical signs of atrophic rhinitis . Comparison of the results from the colony lift-hybridization assay with those from conventional testing, based on a combination of colony morphology, biochemical reactions, mouse lethality, and enzyme-linked immunosorbent assay, indicated that the colony lift assay has superior sensitivity and comparable specificity . This technique has wide application for diagnostic and experimental studies.

FEMS Microbiol Lett, 1998 Sep 15, 166(2), 289 - 96
The capsule biosynthetic locus of Pasteurella multocida A:1; Chung JY et al.; Pasteurella multocida is the aetiological agent of fowl cholera, bovine haemorrhagic septicaemia and atrophic rhinitis in pigs . Many strains of P . multocida express a capsule on their surface . However, nothing is known about the capsule biosynthetic locus in P . multocida although the capsule has been implicated as a virulence factor . The entire capsule locus of P . multocida A:1 was cloned and sequenced . The locus is divided into three regions . Region 1 comprises four ORFs which are involved in the transport of the capsule polysaccharide to the surface . Region 2 comprises five ORFs whose postulated protein products are involved in the biosynthesis of the polysaccharide capsule . Region 3 comprises two ORFs whose postulated products show similarity to proteins that are involved in the phospholipid substitution of the polysaccharide capsule.

Res Microbiol, 1998 Feb, 149(2), 83 - 94
Transport of glucose by a phosphoenolpyruvate:mannose phosphotransferase system in Pasteurella multocida; Binet MR et al.; Pasteurella multocida was examined for glucose and mannose transport . P . multocida was shown to possess a phosphoenolpyruvate (PEP):mannose phosphotransferase system (PTS) that transports glucose as well as mannose and was functionally similar to the Escherichia coli mannose PTS . Phosphorylated proteins with molecular masses similar to those of E . coli mannose PTS proteins were visualized when incubated with 32P-PEP . The presence of an enzyme IIAGlc which could play an important role in regulation, as described in other Gram-negative bacteria, was detected . The enzymes of the pentose-phosphate pathway were present in P . multocida growth on glucose . The activity of 6-phosphofructokinase (the key enzyme of the Embden-Meyerhof pathway (EMP)), was very low in cell extracts, suggesting that EMP is not the major pathway for glucose catabolism.

J Comp Pathol, 1998 Aug, 119(2), 149 - 58
Morphological effects of Pasteurella multocida type-D dermonecrotoxin on rat osteosarcoma cells in a nude mouse model; Dyer NW et al.; Of 15 athymic nude mice that received subcutaneous implants of a rat osteosarcoma cell line, two groups of four subsequently received either a short (group 1) or a more prolonged (group 2) course of subcutaneous injections of the dermonecrotic toxin (DNT) of Pasteurella multocida type D . The remaining seven mice (controls) received no DNT . Both groups of DNT-treated mice lost body weight as compared with controls . Tumour weight, expressed as a percentage of body weight, increased in the four group 1 mice . Tumours in this group 1 were consistently larger than those in appropriate controls, indicating that this percentage was not simply a function of decreased body weight . The immunohistochemical labelling of proliferating cell nuclear antigen (PCNA) and morphometric analysis of intratumoral necrosis suggested that the DNT had a mitogenic effect and contributed to the neoplastic growth . The presence of foci of neoplastic osteoblasts in the lungs of some DNT-treated mice suggested that the enhanced tumour growth led to an increased incidence of metastasis.

Acta Paediatr Jpn, 1998 Aug, 40(4), 360 - 1
Bacterial croup caused by Pasteurella haemolytica; Watanabe T et al.; We report a case of bacterial croup caused by Pasteurella haemolytica . A nine-month-old girl was admitted to our hospital because of abrupt onset dyspnea and unconsciousness . From clinical and laboratory findings, she was diagnosed as having bacterial croup . Pasteurella haemolytica was recovered from her tracheal secretion on admission . To our knowledge, this is the first report of bacterial croup caused by P . haemolytica.

Calcif Tissue Int, 1998 Oct, 63(4), 340 - 5
Pasteurella multocida toxin stimulates bone resorption by osteoclasts via interaction with osteoblasts; Mullan PB et al.; In this study we used an in vitro assay system with osteoblast and osteoclast co-cultures to assess the effect of purified recombinant Pasteurella multocida toxin on bone resorption . Resorption was measured by the release of a telopeptide breakdown product of type I collagen . It was found that P . multocida did not stimulate bone resorption by osteoclasts directly and also did not stimulate bone breakdown via the release of collagenase or other proteases from osteoblasts . During co-culture of osteoblasts and osteoclasts, with cell-cell contact prevented, P . multocida toxin produced no significant effect . Osteoblast-conditioned media gave a biphasic effect; low concentrations of P . multocida toxin stimulated bone resorption, whereas 100 ng/ml inhibited resorption by osteoclasts . However, when both cell types were co-cultured with cell-cell contact permitted, P . multocida toxin induced a large concentration-dependent increase in bone resorption over a 7-day period . This suggested that P . multocida toxin causes bone breakdown via an osteoblast-dependent mechanism and that a membrane-bound receptor may be involved.

Ugeskr Laeger, 1998 Aug 17, 160(34), 4860 - 3
{Bacterial infections as complications of dog bites}; Hermann CK et al.; Dog bites may result in serious bacterial infections with e.g . the gram-negative rods Capnocytophaga canimorsus and Pasteurella multocida . Human disease caused by these microorganisms can be complicated by acute development of septicaemia and/or meningitis followed by disseminated intravascular coagulation syndrome, peripheral gangrene and renal failure . The mortality of C . canimorsus septicaemia is about 23-31% . These severe infections are most often reported in immunocompromised patients and occur a few days after the bite . By reviewing the literature it is concluded that the broadest prophylactic coverage is obtained by amoxicillin/clavulanic acid and that antibiotic prophylaxis should be given to all immunocompromised patients experiencing a dog bite . Moreover, prophylactic treatment should be initiated for all patients with greater penetrating wounds and those involving the hands.

Am J Vet Res, 1998 Sep, 59(9), 1108 - 12
Comparison of radiographic and necropsy findings of lung lesions in calves after challenge exposure with Pasteurella multocida; Jones GF et al.; OBJECTIVES: To test suitability of radiographic evaluation of lung lesions as a substitute for lung lesion scores derived by examination at necropsy in challenge-exposure models of bovine pneumonia . ANIMALS: 10 calves selected by body weight from 20 multiple-source male Holstein calves approximately 1 to 2 months old enrolled in a Pasteurella multocida challenge-exposure study . PROCEDURE: Calves were paired on the basis of weight and randomly assigned within pairs to vaccine or control (saline solution) group . By use of deep tracheal cannulation, calves were challenge exposed with a culture of virulent P multocida, observed for 10 days, euthanatized, and necropsied, and the lungs were scored for pneumonic lesions . Radiographic views of the lung fields of the calves were taken before challenge exposure and before necropsy and were evaluated for alveolar disease by a veterinary radiologist . Lung lesion scores were compared with radiographic evaluations . RESULTS: There was a strong and significant correlation (R2 = 0.91, P < 0.001) between results of the evaluation of postchallenge-exposure radiographs and necropsy results . There also was also strong and significant correlation (R2 = 0.90, P < 0.001) between evaluation of the prechallenge-exposure radiographs and necropsy results . CONCLUSIONS: Radiographic evaluation of lung lesions correlates well with lung lesions found at necropsy . The findings emphasize the need for caution in interpreting the results of challenge-exposure studies of bovine respiratory tract disease in which small numbers of calves are studied.

Int J Syst Bacteriol, 1998 Jul, 48 Pt 3, 929 - 33
Actinobacillus scotiae sp . nov., a new member of the family Pasteurellaceae Pohl (1979) 1981 isolated from porpoises (Phocoena phocoena); Foster G et al.; Phenotypic and phylogenetic studies were performed on a Gram-negative, rod-shaped bacterium isolated from three porpoises . Biochemical and physiological studies indicated that the bacterium was related to the family Pasteurellaceae . Comparative 16S rRNA gene sequencing studies confirmed these findings and demonstrated that the bacterium represents a hitherto unknown subline . The nearest phylogenetic relative of the unknown bacterium was Actinobacillus delphinicola, an organism also originating from sea mammals, although a sequence divergence of 3% demonstrated that the newly isolated bacterium is a distinct species . On the basis of the results of the phylogenetic analysis and phenotypic criteria, it is proposed that the bacterium should be classified as a new species, Actinobacillus scotiae sp . nov . The type strain of Actinobacillus scotiae sp . nov . is NCTC 12922T (= M2000/95/1T).

Curr Microbiol, 1998 Oct, 37(4), 240 - 4
In vivo production of neuraminidase by Pasteurella haemolytica in market stressed cattle after natural infection; Straus DC et al.; Pasteurella haemolytica (Ph) is the most important cause of the bovine acute fibrinohemorrhagic pneumonia that occurs in market stressed calves after shipment to feedyards . Recent characterization of neuraminidase production by these organisms has shown that all 16 serotypes produce an immunologically similar form of the enzyme . Anti-neuraminidase antibody against PhA1 and PhA6 was determined in 101 2- to 5-month-old calves, on their farms of origin, at the order buyer barn (OBB), and through 28 days in the feedyard . Half of the calves were vaccinated with a killed Ph serotype-A1 (PhA1) product . Nasal secretion and tonsil wash specimens were cultured for Ph and Pasteurella multocida (Pm) . Serum antibody against PhA1 and PhA6 was measured by indirect hemagglutination (IHA), and anti-neuraminidase antibody was determined by the neutralization assay . At the feedyard, 73 calves had respiratory tract disease . IHA values ranged between 1:2 and 1:1024 for PhA1 and between 1:2 and 1:512 for Ph serotype A6 (PhA6) . Forty-two, 24, and 28% of the calves were infected with PhA1, PhA6, and Pm, respectively . Ninety-six percent of the calves experienced an increase in anti-PhA1 neuraminidase antibody when sera drawn on feedyard day 28 were compared with sera drawn on the farm . These data demonstrate that the enzyme neuraminidase is produced in vivo in market stressed cattle after a natural Ph infection.

J Vet Pharmacol Ther, 1998 Aug, 21(4), 251 - 6
Bioavailability of spiramycin and lincomycin after oral administration to fed and fasted pigs; Nielsen P et al.; The disposition of spiramycin and lincomycin was measured after intravenous (i.v.) and oral (p.o.) administration to pigs . Twelve healthy pigs (six for each compound) weighing 16-43 kg received a dose of 10 mg/kg intravenously, and 55 mg/kg (spiramycin) or 33 mg/kg (lincomycin) orally in both a fasted and a fed condition in a three-way cross-over design . Spiramycin was detectable in plasma up to 30 h after intravenous and oral administration to both fasted and fed pigs, whereas lincomycin was detected for only 12 h after intravenous administration and up to 15 h after oral administration . The volume of distribution was 5.6 +/- 1.5 and 1.1 +/- 0.2 L/kg body weight for spiramycin and lincomycin, respectively . For both compounds the bioavailability was strongly dependent on the presence of food in the gastrointestinal tract . For spiramycin the bioavailability was determined to be 60% and 24% in fasted and fed pigs, respectively, whereas the corresponding figures for lincomycin were 73% and 41% . The maximum plasma concentration of spiramycin (Cmax) was estimated to be 5 microg/mL in fasted pigs and 1 microg/mL only in fed pigs . It is concluded that an oral dose of 55 mg/kg body weight is not enough to give a therapeutically effective plasma concentration of spiramycin against species of Mycoplasma, Streptococcus, Staphylococcus and Pasteurella multocida . The maximum plasma concentration of lincomycin was estimated to be 8 microg/mL in fasted pigs and 5 microg/mL in fed pigs, but as the minimum inhibitory concentration for lincomycin against Actinobacillus pleuropneumoniae and P . multocida is higher than 32 microg/mL a therapeutically effective plasma concentration could not be obtained following oral administration of the drug . For Mycoplasma the MIC90 is below 1 microg/mL and a therapeutically effective plasma concentration of lincomycin was thus obtained after oral administration to both fed and fasted pigs.

Zentralbl Bakteriol, 1998 Jul, 288(1), 1 - 12
Phenotypic and genotypic diversity of organisms previously classified as maltose positive Pasteurella multocida; Petersen KD et al.; Fifteen isolates tentatively classified as maltose positive Pasteurella multocida have been characterized in 79 biochemical tests and by ribotyping using HindIII and HpaII for digestion of DNA . Phenotypic and genotypic results were analysed using the computer programmes NTSYS and GelCompar, respectively . Two strains were classified as maltose positive P . multocida ssp . multocida while six strains were classified as maltose positive P . multocida ssp . septica . The remaining strains clustered with P . volantium and P . gallinarum, but remained unclassified . With the exception of a single isolate correlation was observed between phenotypic and genotypic results . The unclassified isolates which represented three different sources were heterogenous according to both phenotypic and genotypic results . The findings obtained support the 16S rRNA sequencing results indicating that the genus Pasteurella sensu stricto might represent two or more genera.

Indian J Exp Biol, 1998 May, 36(5), 530 - 2
Outer membrane protein of Pasteurella multocida serotype B:2 is immunogenic and antiphagocytic; Srivastava SK; Outer membrane protein (OMP) from Pasteurella multocida serotype B:2 was extracted and studied for its ability to immunize animals against P . multocida infection and to resist phagocytosis by murine peritoneal macrophage . Inoculation of OMP in rabbits resulted in the production of agglutinating antibodies which passively protected mice against P . multocida challenge and caused lysis of virulent P . multocida cells in vitro . Mice vaccinated with OMP vaccine resisted the challenge showing a satisfactory survival rate (67%) similar to mice given commercial whole cell vaccine (84%) . The OMP was also found to be antiphagocytic, interfering with the phagocytosis of opsonized Candida albicans by murine peritoneal cells in vivo . The study suggested the role of OMP in conferring protection in animals against P . multocida infection and enhancing the virulence in infected animals through the anti-phagocytic mechanism.

Scand J Immunol, 1998 Aug, 48(2), 170 - 6
Proliferative responses of peripheral blood leucocytes of sheep infected with Trypanosoma evansi; Onah DN et al.; The effects of Trypanosoma evansi on the proliferative responses of ovine peripheral blood leucocytes (PBL) were examined in in vitro cell culture systems . Sheep were vaccinated against pneumonic pasteurellosis with a monovalent Pasteurella haemolytica vaccine and then infected with T . evansi TREU 2143 . From 1 week post-infection (p.i.), the PBL were separated and stimulated in cultures with either Concanavalin A (Con A), bacterial lipopolysaccharide (LPS), pasteurella antigen (P.ag), or homologous trypanosome antigen (T.ag) . The proliferative responses of the cells to Con A and LPS were significantly (P < 0.001) suppressed by the infection . This suppression was associated with active infection, as treatment of the sheep with a trypanocide restored the proliferative ability of the cells to both mitogens . Similarly, active infection significantly (P < 0.001) suppressed specific responses to P.ag and T.ag but although treatment resulted in full specific proliferative responsiveness to the homologous trypanosome antigen, the same was not true of P.ag, in which the responsiveness of cells from uninfected vaccinated sheep to it were still significantly higher (P < 0.001) than those of cells from infected sheep.

Infect Immun, 1998 Sep, 66(9), 4087 - 92
The biphasic mRNA expression pattern of bovine interleukin-8 in Pasteurella haemolytica lipopolysaccharide-stimulated alveolar macrophages is primarily due to tumor necrosis factor alpha; Lafleur RL et al.; Pasteurella haemolytica serotype 1 is the bacterial agent responsible for the pathophysiological events associated with bovine pneumonic pasteurellosis . Our previous studies support a role for the lipopolysaccharide (LPS) from P . haemolytica in the induction of proinflammatory cytokines . One of the pathological hallmarks of bovine pneumonic pasteurellosis is an influx of neutrophils into the alveolar spaces . This pronounced influx suggests the local production of a chemotactic factor(s) such as interleukin-8 (IL-8) . In the context of the lung, the alveolar macrophage appears to be the major producer of IL-8, a proinflammatory cytokine with potent neutrophil chemotactic activity . By using Northern blot analysis, we have examined the kinetics of IL-8 mRNA expression in P . haemolytica LPS-stimulated bovine alveolar macrophages and found that 1 ng of LPS per ml induces maximal expression of IL-8 mRNA . The results also indicate a biphasic time course expression pattern in which IL-8 mRNA levels peak between 1 and 2 h in the first phase and between 16 and 24 h in the second phase (P < 0.01) . In addition, monospecific polyclonal antibodies were used to demonstrate the role of tumor necrosis factor alpha (TNF-alpha) in the second phase of IL-8 mRNA expression . Our findings support a role for P . haemolytica LPS and TNF-alpha in the induction of IL-8 from bovine alveolar macrophages.

Acta Vet Hung, 1998, 46(1), 85 - 93
Therapeutic efficacy of doxycycline against experimental Pasteurella multocida infection in broiler chickens; Semjen G et al.; The efficacy of doxycycline was investigated in two sets of experiments . In the first experiment 40, in the second experiment 60, hence altogether 100 five-week-old Ross broilers of both sexes were used . The birds were randomly allocated into groups (A and B in experiment 1; A, B and C in experiment 2) of 20 birds in each . All birds were infected intramuscularly with approx . 2 x 10(3) colony forming units of Pasteurella multocida strain X-73 (serotype A:1) . Birds in groups A were non-medicated controls . Chickens in groups B were given doxycycline via the drinking water at a dose of 10 mg/kg body weight for 5 days, while group C was treated with chlortetracycline at a dose of 20 mg/kg body weight for 5 days . The trial lasted for 9 days, then the surviving chickens were sacrificed . Clinical symptoms, number of deaths, post mortem lesions and bacteriological findings were recorded using a special score system . Acute fowl cholera developed in broilers within a few hours after infection, as evidenced by the clinical symptoms, the high mortality rate (90% of the birds died within 4 days after infection), the pathological lesions and the recovery of P . multocida from the challenged birds . Doxycycline reduced the number of deaths (30% and 5% of birds died in experiments 1 and 2, respectively) and the severity of the clinical symptoms, and P . multocida could be re-isolated only from one of the survivors . In contrast, chlortetracycline slightly influenced the mortality; however, it delayed death and reduced the severity of clinical symptoms . These data indicate that doxycycline is highly effective for the treatment of experimental pasteurellosis in chickens.

Vet Res, 1998 May-Aug, 29(3-4), 233 - 54
Pasteurella haemolytica complicated respiratory infections in sheep and goats; Brogden KA et al.; Respiratory infections which commonly occur in sheep and goats often result from adverse physical and physiological stress combined with viral and bacterial infections . Inevitably, Pasteurella haemolytica pneumonia occurs as a result of these interactions . In this review, we present recent advances in research on the complex etiology of pneumonia involving P . haemolytica . Initially stress, induced by factors such as heat, overcrowding, exposure to inclement weather, poor ventilation, handling and transport is a major predisposing factor . Respiratory viruses including parainfluenza 3 (PI-3) virus, adenovirus type 6 and respiratory syncytial virus (RSV), and to a lesser extent bovine adenovirus type 2, ovine adenovirus types 1 and 5, and reovirus type 1 cause respiratory infections and pneumonia . More importantly these viruses also dramatically increase the susceptibility of sheep and goats to secondary P . haemolytica infection . Primary infection of the lower respiratory tract, with Mycoplasma ovipneumoniae and Bordetella parapertussis can increase the susceptibility of sheep and goats to secondary P . haemolytica infection . It is possible that initial infections with viral or primary bacterial agents break down the antimicrobial barrier consisting of beta defensins and anionic peptides found in epithelial cells, resident and inflammatory cells, and serous and mucous secretions of the respiratory tract . Loss of barrier integrity may release P . haemolytica from its usual commensal status . Once in the lung, P . haemolytica becomes opportunistic . To grow and colonize, P . haemolytica uses extracellular products like O-sialoglycoprotein endopeptidase, neuraminidase and RTX leukotoxin, as well as cell-associated products such as capsular polysaccharide, lipopolysaccharide, outer membrane proteins, proteins involved in iron acquisition and a periplasmic superoxide dismutase . In lambs and kids, pneumonic pasteurellosis can be acute, characterized by fever, listlessness, poor appetite and sudden death . Sheep and goats that survive the acute stage may recover or become chronically affected showing reduced lung capacity and weight gain efficiency and sporadic deaths may occur . This infection is detrimental to sheep and goats throughout the world and flocks and herds of small ranches, dairy operations, or large feedlots are all affected.

Antimicrob Agents Chemother, 1998 Aug, 42(8), 2116 - 8
Tn5706, a transposon-like element from Pasteurella multocida mediating tetracycline resistance; Kehrenberg C et al.; The 4,378-bp putative tetracycline resistance transposon Tn5706 of Pasteurella multocida consists of an internal tet(H)-tetR resistance gene region which is flanked by almost identical insertion elements, IS1596 and IS1597 . Two reading frames for proteins of 70 and 228 amino acids were detected in each of these insertion sequence elements . The 228-amino-acid protein revealed homology to transposase proteins of gram-positive bacteria.

Can J Vet Res, 1998 Jul, 62(3), 178 - 82
Comparison of serologic and protective responses induced by two Pasteurella vaccines; Mosier DA et al.; Vaccine development for the prevention of pneumonic pasteurellosis remains a critical issue for the feedlot industry . Most currently available Pasteurella vaccines are formulated to stimulate immunity by either providing an adequate antigenic mass in the administered dose, or by relying on subsequent production of antigens by in vivo growth of live organisms . The ability of these different types of vaccines to stimulate rapid and high titres to key antigens is a key factor that will influence subsequent resistance to disease . The serologic and protective responses to a streptomycin-dependent, modified-live vaccine and a killed (bacterin-toxoid) vaccine against experimental pneumonic pasteurellosis were compared . Calves were vaccinated with a single injection of either a test vaccine or phosphate-buffered saline, challenged 14 d later by transthoracic injection with Pasteurella haemolytica, and euthanized 3 d post-challenge to evaluate the severity of pneumonia . On days 0, 7, and 14, serologic responses to various P . haemolytica antigens, including cell-associated and soluble antigens, were determined by enzyme-linked immunosorbent assays, and anti-leukotoxin antibody levels were determined by leukotoxin neutralization . The bacterin-toxoid elicited significantly greater serologic responses compared to controls for all antigens . The modified-live vaccine elicited a significantly greater response compared to controls for a whole-cell antigen preparation . Lesion scores were significantly smaller (greater protection) in calves that received the bacterin-toxoid, but not the modified-live vaccine, compared to controls.

Vaccine, 1998 Jul, 16(11-12), 1184 - 92
Haemorrhagic septicaemia vaccines; Verma R et al.; Haemorrhagic septicaemia (HS), an economically important disease of cattle and buffaloes, is caused by Pasteurella multocida (6:B) . Vaccination against this disease is widely practised . Plain broth bacterins, or alum precipitated and aluminium hydroxide gel vaccines are administered twice a year since these vaccines offer an immunity of 4-6 months . Many countries use oil adjuvant vaccine (OAV), which gives both a higher degree and a longer duration of immunity up to 1 year . A double emulsion and multiple emulsion vaccine consisting of a thin viscosity have also been experimentally developed that gave an immunity parallel to OAV . Recently, a live vaccine developed from a fallow deer strain (B:3,4) has been used in Myanmar that offers an immunity for more than a year but is not free from constraints . The present review provides information on HS vaccines developed from time to time using whole bacteria or their components . The kinetics and isotype of antibody and cell-mediated immune responses have also been poorly understood so far, and hence information on their role in protection against HS is reviewed.

J Vet Pharmacol Ther, 1998 Jun, 21(3), 199 - 202
Water medication of a swine herd with amoxycillin; Agerso H et al.; A swine herd, consisting of 201 swine, was treated with amoxycillin . Amoxycillin was administered in the water system for 5 days, at a mean dose of 23 mg/kg body weight per day . Twice a day the water consumption was monitored, and blood samples collected from 10 randomly selected pigs . The plasma concentration of amoxycillin was measured by use of high performance liquid chromatography (HPLC) . Three days after initiating amoxycillin treatment, the plasma concentration reached a constant level, at which it varied between a maximum of 1.3 micrograms/mL and a minimum of 0.5 microgram/mL . The plasma concentration was compared with a predicted curve based on pharmacokinetic variables obtained previously . The plasma concentrations were at the same level as the simulated ones . The minimum inhibitory concentration (MIC) values of the common respiratory pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida are about 0.1 microgram/mL . In pigs the distribution between bronchial mucosa and plasma (AUCmucosa/AUCplasma) is 0.3, which indicates a therapeutic plasma concentration of 0.3 microgram/mL . Data from the present study indicates that water medication with amoxycillin is effective as follow-up treatment.

Aust Vet J, 1998 Jun, 76(6), 423 - 5
Diversity among isolates of Actinobacillus equuli and related organisms as revealed by ribotyping; Blackall PJ et al.; OBJECTIVE: The objective of this work was to examine the diversity within Australian isolates of Actinobacillus equuli and related organisms by the genotypic method of ribotyping . DESIGN: Ribotyping, performed using the enzyme HaeIII, was used to examine the diversity in 12 field isolates of A equuli (five being capable of fermenting L-arabinose), one field isolate of Pasteurella caballi and two unclassifiable field isolates . Isolates were obtained from Australian horses, except for three isolates of A equuli (one L-arabinose positive and two L-arabinose negative) which were obtained from horses and a pig in Africa . In addition, the type strains for A equuli and P caballi and a reference strain for Bisgaard Taxon 9 were included in the study . RESULTS: The ribotype patterns were analysed by computerised cluster analysis, yielding five clusters (A to E) . All five of the L-arabinose positive A equuli were assigned to cluster A, with all the other seven A equuli isolates (all L-arabinose negative) and the type strain being assigned to cluster B . One of the two unclassified isolates formed cluster C along with the reference strain for Bisgaard Taxon 9 . The remaining unclassified isolate formed cluster D . Cluster E consisted of the field isolate and reference strain of P caballi . CONCLUSION: The results of this study indicate that A equuli is a diverse species, with L-arabinose positive isolates of A equuli being quite distinct from typical L-arabinose negative isolates . Ribotyping appears to be a useful tool in confirming the identity of A equuli-like organisms from horses.

Zentralbl Veterinarmed A, 1998 Apr, 45(3), 175 - 80
Chloramphenicol pharmacokinetics after intravenous and intramuscular administration in sheep; Mestorino ON et al.; The pharmacokinetics of chloramphenicol were studied after intravenous and intramuscular administration of 50 mg/kg body weight in Merino sheep . After intravenous administration, the drug was rapidly distributed extravascularly with a half-life of 10.5 +/- 8.83 min . Extensive distribution was confirmed by an apparent volume of distribution at steady state (1.5 +/- 0.43 1/kg) . The elimination half-life was 3.24 +/- 0.60 h . After intramuscular injection, the absorption half-life was 44.33 +/- 19.21 min with a bioavailability of 65% . A maximum serum concentration of 15.57 +/- 3.95 micrograms/ml was determined 2 h after administration . Serum concentrations above 5 micrograms/ml were maintained for approximately 12 h with an elimination half-life of 5.75 +/- 1.25 h, longer than the half-life obtained after intravenous administration . In conclusion, the intramuscular administration of chloramphenical at a dose rate of 50 mg/kg permitted the maintenance of inhibitory concentrations of the antibiotic for the majority of Salmonella and Pasteurella isolates for at least 12 h.

Infect Immun, 1998 Aug, 66(8), 3788 - 95
Induction of protective immunity in rabbits by coadministration of inactivated Pasteurella multocida toxin and potassium thiocyanate extract; Jarvinen LZ et al.; Pasteurella multocida is a bacterial pathogen that causes rhinitis (snuffles), pneumonia, otitis media, septicemia, metritis, and death in domestic rabbits . Currently, there are no effective vaccines to prevent infection by this organism . Subcutaneous (s.c.) immunization with either exotoxin or thiocyanate extracts of P . multocida induces partial protection in rabbits . Since disease begins at mucosal sites, induction of local immunity may be important in preventing systemic disease . Little is known concerning the efficacy of intranasal (i.n . ) administration of these antigens in inducing protective mucosal immunity to P . multocida in rabbits . The purpose of this study was twofold: (i) to investigate the effectiveness of vaccination with purified P . multocida toxin (PMT) and a potassium thiocyanate extract of P . multocida (CN) in combination and (ii) to evaluate the efficacy of administration of these antigens i.n . versus s.c . Forty-eight rabbits were randomly divided into eight different treatment groups . Rabbits received either one or both antigens by either s.c . or i.n . administration . Following vaccination, each group received an i.n . challenge of P . multocida . Rabbits vaccinated with both antigens i.n . or s.c . had a 100% survival rate, few or no bacteria in the liver and lungs, high serum immunoglobulin G (IgG) and IgM antibody titers, and significant numbers of IgG antibody-secreting cells (ASC) in the spleen and tracheobronchial lymph node . Rabbits vaccinated i.n . had significant nasal and bronchoalveolar lavage IgA antibody levels . Rabbits vaccinated with only one antigen, either PMT or CN, had lower antibody titers, moderate to severe liver and lung infections, and fewer ASC compared to rabbits receiving both antigens . Rabbits in the control groups had moderate to severe liver and lung infections . This study indicates that i.n . immunization with both PMT and CN induces an effective response against homologous P . multocida challenge.

Leuk Lymphoma, 1998 Jun, 30(1-2), 23 - 30
CD34 molecule epitope distribution on cells of haematopoietic origin; Steen R et al.; The CD34 molecule belongs to the mucin membrane molecule family and is expressed on virtually all normal haematopoietic progenitor cells (HPC) . Due to its heavy glycosylation, several different epitopes exist on the molecule . Based on the sensitivity of the glycosylated molecule to degradation with a glycoprotease from Pasteurella haemolytica and neuraminidase, three classes of epitopes have been identified . The class I and II epitopes are probably related to the glycosylated part of the molecule while class III epitopes are core protein related . It has been known for some time that CD34 class I epitopes are absent on CD34 molecules expressed on high endothelial venules . Here we review recent observations that expression of both class I and II epitopes, but not class III epitopes, is impaired on mature myeloid CD34-pos . HPC while no diverse class epitope expression was observed on immature HPC . In addition, cells from patients with CD34-pos . acute myeloid leukaemia of FAB classification M4-M5, i.e., leukaemic blast cells of relatively mature morphologic phenotype, also express less class I and II epitopes than class III epitopes . It therefore seems that HPC maturation and class I and II epitope deprivation are concomitant events and that CD34 class I and II epitopes are lost prior to downregulation of the CD34 molecule per se . The biological significance of this observation is discussed as well as the need to carefully select CD34-specific monoclonal antibodies for research and clinical purposes.

Ann N Y Acad Sci, 1998 Jun 29, 849, 479 - 84
Toxin production by Pasteurella granulomatis; Veit HP et al.; Pasteurella granulomatis (Pg) is a recently identified bacterium associated with proliferative fibrogranulomatous panniculitis (also called "lechiguana") in Brazilian cattle . Recent attempts to experimentally reproduce this disease have only been partially successful . We hypothesized that Pg may produce hemolysin(s) and/or cytotoxin(s) which could contribute to its pathogenicity in susceptible cattle . The objective of this study was to determine the presence and degree of hemolytic and leukotoxic activity of selected isolates of Pg . Either ovine or bovine blood agar plates were streaked with 1 of 7 Pg isolates, incubated at 37 degrees C +/- 1 C for 48 hours, and examined for hemolysis . Two of seven isolates showed hemolytic activity on bovine plates, while all seven showed hemolytic activity on ovine plates . By use of the CAMP reaction, involving simultaneous intersecting cultures of Staphylococcus aureus and Pg, all seven Pg isolates showed enhanced (positive CAMP) hemolysis within 24 hours on bovine blood agar plates . Preliminary results using tetrazolium (MTT) dye reductions with bovine neutrophils showed leukotoxicity in 13 of 16 Pg cultures . Alamar blue tests indicate leukotoxic activity for all 7 Pg isolates . We conclude that some Pg isolates have variable hemolytic and/or leukotoxic properties and that this variability (presence and/or degree) of these 2 properties may affect the relative pathogenicity of Pg in susceptible cattle.

Clin Diagn Lab Immunol, 1998 Jul, 5(4), 494 - 8
Effect of ovalbumin aerosol exposure on colonization of the porcine upper airway by Pasteurella multocida and effect of colonization on subsequent immune function; Hamilton TD et al.; Seventy-three piglets were weaned at 1 week of age, randomly assigned to 10 groups (A to J), accommodated in stainless steel exposure chambers, and exposed continuously to a controlled environment containing aerosolized ovalbumin . The concentrations of ovalbumin dust were as follows (milligrams per cubic meter): A and F, 16.6; B and G, 8.4; C and H, 4.2; D and I, 2.1; E and J, 0 . At weekly intervals, the pigs were bled via venipuncture and anesthetized for nasal lavage and tonsilar biopsies performed for subsequent bacteriologic analysis . At 2 weeks of age, the pigs in groups A to E were challenged with toxigenic Pasteurella multocida (10(8) CFU pig(-1)), and at 6 weeks of age, the pigs were euthanatized . At postmortem, the extent of turbinate atrophy was assessed on the snout sections by using a morphometric index . Exposure to aerial ovalbumin resulted in a dose-dependent increase in serum antiovalbumin immunoglobulin G (IgG; P < 0.001) and serum antiovalbumin IgA (P < 0.001) . Exposure also caused a significant increase in the numbers of P . multocida organisms isolated from the upper respiratory tract (P < 0.001) and a corresponding increase in turbinate atrophy, as judged by the morphometric index (P < 0.001) . Concurrent challenge with P . multocida and ovalbumin resulted in a significant decrease in both the IgG and IgA responses to ovalbumin (P < 0.001) . These results show that ovalbumin exposure increases pig susceptibility to P . multocida colonization and that toxigenic P . multocida modifies the serum IgG and IgA responses to ovalbumin in the pig . Both of these effects may enhance the virulence of this respiratory pathogen and so influence the pathogenesis of atrophic rhinitis in pigs.

Curr Microbiol, 1998 Aug, 37(2), 132 - 6
Pasteurella haemolytica ultraviolet-irradiated vaccine by parenteral and aerosol routes compared in the goat model; Purdy CW et al.; Positive control 1 (PC1) (n = 9) goats were injected transthoracically into the left lung with live Pasteurella haemolytica biovar A, serovar 1 (PhA1) in polyacrylate (PA) beads on days 0 and 21 . Positive control 2 (PC2) (n = 6) goats were nebulized with live PhA1 and PA beads on days 0 and 21 . Negative control (NC) goats (n = 6) were each injected transthoracically into the left lung with PA beads alone on days 0 and 21 . Four groups (n = 6) were administered PA beads mixed with ultraviolet (UV) killed PhA1 on days 0 and 21 . The treatment doses of bacteria for these groups were principal group 1 (PR1) injected into the left lung (7.7 x 10(10) cfu); PR2, 7.7 x 10(10) UV-killed PhA1 injected subcutaneously (SC); PR3, 7.7 x 10(10) UV-killed PhA1 injected SC only on day 21; PR4, nebulized with PA beads mixed with 5.6 x 10(10) cfu of UV-killed PhA1; and PR5, nebulized with PA beads mixed with 5 x 10(8) cfu of UV-killed PhA1 . All goats were challenged transthoracically in the right lung with 1 x 10(8) cfu of live PhA1 on day 42 and necropsied on day 46 . The sizes of consolidated lung lesions at the challenge site were used as a measure of immunity . The data show that the introduction of live PhA1 into the lungs of goats, either by injection or aerosolization, offers excellent protection against a subsequent homologous challenge . The data also demonstrate that two transthoracic injections (21 days apart) of UV-killed PhA1 (PR1), and subcutaneous injection of UV-killed PhA1(PR2) also offer excellent protection against a subsequent homologous live PhA1 challenge . One SC injection of UV-killed PhA1 (PR3) appears to offer only partial protection against a subsequent homologous live PhA1 challenge . Inhalation of UV-killed PhA1 mixed with PA beads (PR4 and PR5) induced no protection in goats against a subsequent live PhA1 transthoracic challenge.

J Pediatr Surg, 1998 Jun, 33(6), 863 - 5
Cougar attacks on children: injury patterns and treatment; Kadesky KM et al.; PURPOSE: Cougar attacks on humans appear to be on the rise . A review of all attacks on children was performed to determine the method of attack and injury patterns so that a treatment regimen as well as possible preventative measures could be determined . METHODS: A review of all attacks, including attacks on children, was performed, including three recent attacks treated at our institution . Situation, adult supervision, patient age, injuries recorded, survival, and mode of attack, if known, were reviewed . RESULTS: There were 50 documented attacks on children with a 25% fatality rate . Most children were not alone at the time of the attack (92%), and in many instances adult supervision was present or nearby . Severe head and neck lacerations along with puncture wounds were the most common injury . Examples of typical cervical injuries include a nonfatal vertebral artery injury, phrenic nerve injury, a fatal internal carotid artery injury, and a fatal cervical spine injury . The cougar was rabid in two cases . Pasteurella resulted in late infections in two patients . CONCLUSIONS: Based on the pattern of injuries, the authors recommend aggressive evaluation for occult cervical injuries as well as surgical debridement . Antibiotics should cover oropharyngeal flora including Pasteurella multocida . Rabies prophylaxis is indicated . Adult supervision in wilderness areas is not necessarily protective.

J Biomed Mater Res, 1998 Sep 5, 41(3), 359 - 63
The effect of recombinant human bone morphogenetic protein-2 on the integration of porous hydroxyapatite implants with bone; Koempel JA et al.; To determine if recombinant human bone morphogenetic protein-2 (rhBMP-2) can be adsorbed onto porous ceramic hydroxyapatite (HA) and promote the integration of HA to host bone, 54 subperiosteal pockets were created on the skulls of 19 adult Pasteurella-free white rabbits . Fourteen HA implants were saturated with saline and placed in subperiosteal pockets (control), 22 HA implants were saturated with saline and placed into subperiosteal pockets after burring 1-2 mm of calvarium to expose bleeding cancellous bone, and 18 HA implants were saturated with rhBMP-2 and placed into subperiosteal pockets . The animals were sacrificed at 1 month with examination to determine implant mobility . Histology was used to determine the amount of bone growth into the implant . Of the 14 control sites, 10 implants were found to be freely mobile, five demonstrated host bone resorption, and only one exhibited bone growth into the implant . Of the 22 burred sites, eight were freely mobile and 10 demonstrated bone growth into the implant (p = 0.04) . Of the 18 rhBMP-2 sites, only two were freely mobile, none demonstrated host bone resorption, and 16 exhibited bone growth into the implant (p = 0.00002) . This study supports the use of porous ceramic HA as a biocompatible, osteoconductive implant material for use in craniomaxillofacial augmentation and reconstruction . It also provides evidence that rhBMP-2 enhances osseointegration, thereby fixing the implant in position against the host-bone interface . In the clinical setting, osseous fixation of the implant should aid in preventing displacement, minimizing host bone resorption, and decreasing the incidence of extrusion.

Am J Vet Res, 1998 Jul, 59(7), 851 - 5
Serum-free culture of Pasteurella haemolytica optimized for leukotoxin production; Sun Y et al.; OBJECTIVE: To screen supernatants of Pasteurella haemolytica cultures grown in 4 serum-free culture media for maximal leukotoxin (LKT) production and minimal protein concentration as an optimal source of LKT for purification . SAMPLE POPULATION: One strain of P haemolytica biotype A serotype 1 originally isolated from the pneumonic lung of a calf . PROCEDURE: Pasteurella haemolytica was grown in brain-heart infusion (BHI) broth, yeast-tryptone broth, RPMI-1640 medium, and McCoy's modified 5A medium . Culture biomass and protein concentration, LKT activity, and LKT concentration in culture supernatants were measured . Effects of media pH and supplementation with metal cations and glucose on growth rate of P haemolytica and culture supernatant parameters were evaluated . RESULTS: Pasteurella haemolytica cultivated in BHI broth or RPMI-1640 medium containing 0.1 M phosphate (pH 6.8) produced the highest concentrations of LKT . Supplementation of RPMI-1640 medium with 0.36 mM FeCl3 or 1.0 mM MgSO4 further increased specific activity of LKT in culture supernatant, but addition of 1% glucose did not enhance LKT production . Leukotoxin production in MgSO4-supplemented RPMI-1640 medium was comparable to that in serum protein-supplemented medium . CONCLUSIONS: Although BHI broth was superior to RPMI-1640 medium for P haemolytica growth and LKT production, the higher protein concentration and lower LKT specific activity made BHI broth a less desirable medium, compared with RPMI-1640 medium . Growth rate and LKT production with minimal protein content was optimal in pH 6.8 phosphate-buffered MgSO4-supplemented RPMI-1640 medium . This medium can serve as a source of culture supernatant for purification of LKT.

Vet Immunol Immunopathol, 1998 May 29, 63(3), 209 - 22
Increase in CD5+ B cells and depression of immune responses in sheep infected with Trypanosoma evansi; Onah DN et al.; The effects of Trypanosoma evansi on the cellular and humoral immune responses of sheep to Pasteurella haemolytica vaccine were studied . Peripheral blood lymphocytes (PBLs) from the sheep were analysed using single and double-colour indirect immunofluorescence staining and flow cytometry to monitor changes in circulating B and T cell subsets . Serum antibody responses were assayed using the enzyme-linked immunosorbent assay technique (ELISA), in addition to measuring local skin reactions at the site of vaccine administration . Results showed significant increases in circulating B cells in all sheep after the primary (p < 0.01) and secondary (p < 0.001) vaccinations although the increases were much more dramatic in the T . evansi-infected sheep . In addition, infection induced significant increases (p < 0.004) both in proportions and numbers of CD5+ B cells with more than 70% of circulating B cells expressing the CD5 antigen and showed significant differences (p < 0.01) from those of control sheep in which vaccination alone failed to induce similar increases . Also, infection resulted in significant decreases in CD5+ (p < 0.003), CD4+ (p < 0.03) and CD8+ (p < 0.03) T cell subsets in contrast to their increases in all control animals after vaccination . Moreover, there were significant suppression of both local skin reaction (p < 0.005) and serum Ig and IgG1 (p < 0.001) antibody responses to the vaccine antigen.

J Chromatogr A, 1998 May 29, 808(1-2), 167 - 76
High-performance liquid chromatography of Pasteurella haemolytica leukotoxin using anion-exchange perfusion columns; el Rassi Z et al.; An exotoxin, called leukotoxin (LKT), from Pasteurella haemolytica, which had previously proved difficult to purify, was purified by high-performance liquid chromatography using rigid highly hydrophilic microparticulate anion-exchange columns . These anion-exchange stationary phases were employed to overcome difficulties of the relatively hydrophobic LKT interacting with dextran or styrene-based resins . While a short non-porous DEAE column allowed the partial microscale purification of the leukotoxin at pH 7.0, a high capacity strong anion-exchange column of the perfusion chromatography type permitted the purification of LKT on a much larger scale . The purification of the LKT on the large pore strong anion-exchange perfusion column was best achieved when three consecutive linear gradients at increasing NaCl concentration in 20 mM Tris buffer, pH 8.0, containing 6.0 M urea and 0.25% Tween 20 were used . Under these conditions, a better separation was obtained for the tetrameric and aggregate peaks of LKT from the early eluting contaminant peaks . This separation scheme allowed good recovery of activity and purification of the LKT to near homogeneity.

J Comp Pathol, 1998 May, 118(4), 359 - 63
The carriage of Pasteurella haemolytica in sheep and its transfer between ewes and lambs in relation to mastitis; Scott MJ et al.; The possible presence of Pasteurella haemolytica in the mouth of lambs and on the skin of the teats of ewes was investigated . The organism was found in the mouth of ewes and lambs and, soon after lambing, on the teat skin of ewes . It was not isolated from the teat skin of pregnant ewes 1-14 days before lambing or from the teat skin one week after the lambs had been weaned . The transfer of P . haemolytica to the teat skin is undoubtedly mediated by the lamb . There is ample opportunity for the teat orifice to be exposed to P . haemolytica during the suckling period and it is known that only a few colony-forming units of virulent organisms are required to initiate mastitis.

J Comp Pathol, 1998 May, 118(4), 291 - 300
Pasteurella multocida infection in the chicken embryo; Ibrahim RS et al.; Pasteurella multocida infection in embryonated chicken eggs was studied by chorio-allantoic membrane inoculation . Strain differences were demonstrated in terms of lesion severity and time to death, especially during the first 24 h post-inoculation . A strain of low virulence gave a clear dose response but more virulent strains did not . Comparable results were obtained by infecting 6-week-old chickens . The main lesions in inoculated embryos appeared as severe vascular involvement of the entire embryo and feather tracts, thickening of the chorio-allantoic membrane, and enlargement and congestion of the yolk sac . The bacteria were demonstrated by transmission electron microscopy, either extracellularly or multiplying intracellularly in hepatocytes, heart tissue, and in the hyperplastic layer of the chorio-allantoic membrane, with resulting damage to the cellular organelles, and severe tissue changes.

Vet Microbiol, 1998 Mar 15, 61(1-2), 81 - 91
Bovine platelet adhesion is enhanced by leukotoxin and sialoglycoprotease isolated from Pasteurella haemolytica A1 cultures; Nyarko KA et al.; Platelet and fibrin deposits are among characteristic changes observed in lung alveoli of cattle with pasteurellosis induced by Pasteurella haemolytica (biotype A, serotype 1) . To determine whether the platelet function could be directly affected by protein products produced by the bacterium, the effects of leukotoxin and O-sialoglycoprotease, culture supernatant antigen secreted by Pasteurella haemolytica A1, on bovine platelet activation were examined by evaluating the enhancement of platelet adhesion to a negatively charged surface relative to untreated control samples . The glycoprotease, or the leukotoxin, was added to plasma free suspensions of bovine platelets and platelet adhesion assessed by two parameters: (i) the number of 3H-adenine-labeled adherent platelets and (ii) the morphology of unlabeled platelets adhering to the charged surface under scanning electron microscopy (SEM) . In the presence of calcium, the glycoprotease produced a dose-dependent increase in adhesion . At a concentration of 4.0 micrograms glycoprotease extract protein per 10(7) platelets, a 2-fold increase in adhesion was observed which was similar to the increase in adhesion induced by 0.10 units of thrombin, a known platelet agonist . Both increased platelet adhesion and platelet aggregation were observed with 0.8 microgram glycoprotease extract protein in the presence of calcium . The response of the bovine platelet suspensions to leukotoxin extract protein was dependent on the dosage of the leukotoxin . Adhesion was enhanced at dosages of 25 micrograms leukotoxin protein per 10(7) platelets and below, while at dosages of 50 micrograms and above adhesion was suppressed . Thus, the two proteins secreted by P . haemolytica may interact directly with bovine platelets to initiate platelet aggregation and fibrin formation in alveolar tissue in pneumonic pasteurellosis.

Avian Dis, 1998 Apr-Jun, 42(2), 413 - 7
Pasteurella multocida infection involving cranial air spaces in White Leghorn chickens; Gustafson CR et al.; Seven 18-wk-old pullets from a commercial layer flock experiencing increased mortality associated with neurologic and respiratory symptoms were submitted to the California Veterinary Diagnostic Laboratory System at the Turlock Branch for necropsy . Clinical signs included depression, torticollis, swollen eyelids, conjunctivitis, and sinusitis . Meningoencephalitis and suppurative inflammation of the cranial air spaces were found on histopathology . The brain, sinuses, and air spaces of the cranium were infected with Pasteurella multocida . Complicating the condition was Mycoplasma gallisepticum infecting the sinus and paramyxovirus-I affecting the trachea.

Avian Dis, 1998 Apr-Jun, 42(2), 265 - 74
Differentiating turkey postvaccination isolants of Pasteurella multocida using arbitrarily primed polymerase chain reaction; Hopkins BA et al.; The chromosomal DNA of 29 field isolants of Pasteurella multocida from commercial turkey farms in Missouri and the avirulent Clemson University (CU) and M-9 vaccine strains of P . multocida were tested using the arbitrarily primed polymerase chain reaction (AP-PCR) in combination with 32P-labeled deoxycytidine triphosphate (dCTP) and high-resolution gel electrophoresis . The 29 field isolants of P . multocida were isolated from outbreaks of fowl cholera in turkey flocks in which vaccination with the CU vaccine had been performed within 2 weeks of the isolation, and it was suspected that the outbreak could have been due to the use of the live CU vaccine . The results of this study showed that: 1) the use of the live CU vaccine can lead to the isolation of the vaccine strain if the outbreak occurs within 2 weeks of vaccination; 2) a higher proportion of field isolants collected during 1983 and 1984, when the usage of the CU vaccine strain was highest on Missouri turkey farms, had PCR-amplified product profiles similar or identical to those of the CU vaccine strain compared with the period between 1987 and 1992, when its use was less; and 3) there was no relationship between the PCR-amplified product profiles and the serotype.

Am J Vet Res, 1998 Jun, 59(6), 765 - 71
Anti-inflammatory benefits of tilmicosin in calves with Pasteurella haemolytica-infected lungs; Chin AC et al.; OBJECTIVES: To determine whether tilmicosin alters neutrophil infiltration or function, induces neutrophil apoptosis, and affects accumulation of leukotriene B4 (LTB4) or tumor necrosis factor-alpha (TNF-alpha) in lungs of calves experimentally infected with Pasteurella haemolytica . ANIMALS: 12 weight-ranked Holstein calves . PROCEDURE: Calves were given 25% propylene glycol vehicle (n = 5) or tilmicosin (10 mg/kg of body weight; n = 6) subcutaneously, 18 hours and 15 minutes before intratracheal infection with 2 x 10(8) P haemolytica organisms . Two unmanipulated calves served as controls in some experiments . Rectal temperatures were recorded 15 minutes before, and at 3-hour intervals after infection for 24 hours . Samples obtained from bronchoalveolar lavage performed 3 and 24 hours after infection were used to assess colonization by P haemolytica, and neutrophil infiltration . Neutrophil phagocytosis of P haemolytica, membrane leakage as determined by trypan blue exclusion, oxidative function as determined by nitro blue tetrazolium reduction, and apoptosis, using electron microscopy and DNA fragmentation ELISA, were determined . SOluble TNF-alpha and LTB4 were measured from supernatants from bronchoalveolar lavage samples, using ELISA . RESULTS: Treatment with tilmicosin resulted in significant (P < 0.05) clearance of P haemolytica and neutrophil apoptosis at 3 hours, and decreased concentration of LTB4 at 24 hours . Rectal temperatures, neutrophil infiltration, phagocytosis, oxidative functions, membrane leakage, and soluble TNF-alpha concentrations were not significantly affected by tilmicosin . CONCLUSION: Tilmicosin effectively controlled P haemolytica infection, induced neutrophil apoptosis, reduced pulmonary inflammation, and did not affect neutrophil infiltration or function . CLINICAL RELEVANCE: By inducing neutrophil apoptosis, tilmicosin prevents further amplification of inflammatory injury in P haemolytica-infected lungs.

Am J Vet Res, 1998 Jun, 59(6), 727 - 32
Antibody responses to Pasteurella haemolytica 1:A and three of its outer membrane proteins in serum, nasal secretions, and bronchoalveolar lavage fluid from calves; Brennan RE et al.; OBJECTIVE: To determine systemic and mucosal antibody responses in calves to Pasteurella haemolytica 1:A and to 2 major outer membrane proteins (OMP) and 1 major iron-regulated OMP of P haemolytica 1:A . ANIMALS: 23 crossbred calves . PROCEDURE: 2 experiments were performed in the first experiment, 6 calves were vaccinated and challenge exposed intranasally with an aerosol of P haemolytica 1:A and 6 calves were only challenge exposed . In the second experiment, 8 calves were vaccinated in the area of the tracheal bifurcation with an aerosol of P haemolytica 1:A and 3 calves were used as controls . Serum, nasal secretions, and bronchoalveolar lavage (BAL) samples were collected, and IgG1, IgG2, IgA, and IgM titers were determined . Nasal secretions and BAL samples were also submitted for bacterial culture . RESULTS: Serum antibody responses in the 2 groups were similar . Antibody titers in nasal secretions and BAL samples increased in calves vaccinated intranasally . In calves vaccinated in the area of the tracheal bifurcation, antibody titers increased in BAL samples but not in nasal secretions . Antibody responses did not correlate with results of bacterial culture . CONCLUSIONS: Results indicated that intranasal administration of P haemolytica 1:A may be a better method for stimulating protective immune responses in the upper portion of the respiratory tract than lung administration . The single dilution ELISA provided a reliable and economical method for determining antibody titers.

Vet Res Commun, 1998 Apr, 22(3), 147 - 53
Stimulation of the bronchus-associated lymphoid tissue of goats and its effect on in vitro colonization by Pasteurella haemolytica; Effendy AW et al.; Twenty goats of about 7 months of age were divided into five groups . The goats in groups 1 and 2 were exposed once, using an intranasal spray to 2 ml of an inoculum containing 10(6) colony-forming units/ml of living or dead Pasteurella haemolytica A2, respectively . The goats in groups 3 and 4 were similarly exposed twice at a 2-week interval . Group 5 was the untreated control . The number and size of the bronchus-associated lymphoid tissue (BALT) in goats exposed twice to either living or dead organisms were significantly (p < 0.05) increased compared with those exposed once and with the unexposed control . In vitro colonization by living P . haemolytica A2 onto the lung tissue in which the BALT had been stimulated by two exposures of either living or dead organisms was significantly (p < 0.05) reduced . The study indicates that stimulation of the respiratory mucosal immunity may prevent P . haemolytica A2 infection.

Enferm Infecc Microbiol Clin, 1998 Mar, 16(3), 123 - 6
{Dog bite infections associated with CDC group EF-4a . Report of 2 cases}; Almuzara MN et al.; BACKGROUND: Group EF-4 bacteria make up part of the normal flora of the oral cavity of dogs and cats . Few reports have been published on the incidence of human infections by this group of bacteria and these are associated with animal bite or scratch . Two cases of infections by CDC group EF-4 by dog bite were diagnosed in 1996 by the Bacteriology Laboratory of the authors' hospital . These cases are herein described and the biochemical analysis and profile of sensitivity of this little known group of bacteria evaluated . METHODS: Two clinical cases of infection by CDC group EF-4a by dog bite are described . Identification of the bacteria was performed by conventional biochemical tests and quantitative antibiotic sensitivity to 12 antibiotics was carried out by the seried broth macrodilution method . RESULTS: The two strains isolated corresponded to biovar "a" of group EF-4 being sensitive to: ampicillin, ceftriaxone, aminoglycosides, chloramphenicol, rifamipicin, TMS and ciprofloxacin, intermediate sensitivity to erythromycin and were resistant to cefalotine, oxacillin and vancomycin . With respect to penicillin, one of the strains was sensitive and the other presented intermediate sensitivity . Neither of the strains produced beta lactamase . CONCLUSIONS: Although Pasteurella sp . is usually considered in dog bite wounds, the possible presence of group EF-4 should be taken into account since the sensitivity of both microorganisms against penicillin and cefalotin, which are effective against Pasteurella but less active against group EF-4 bacteria differ.

Anal Biochem, 1998 May 15, 259(1), 8 - 15
Membrane protein proteolysis assayed by fluorescence quenching: assay of O-sialoglycoprotein endopeptidase; Jiang P et al.; The assay of the O-sialoglycoprotein endopeptidase of Pasteurella haemolytica has previously used the cleavage of 125I-labeled glycophorin A, measured by SDS-PAGE, autoradiography, gel-slicing, and scintillation counting . A new assay is based on the increased fluorescence which results from proteolytic cleavage of a fluorescence-quenched micellar substrate, 4,4-difluor-5,7-dimethyl-4-bora-3 alpha, 4 alpha-diaza-s-indacene-3-propionic acid conjugated to glycophorin A (BODIPY-FL-glycophorin A) . Micellar association of glycophorin A molecules results in 97% fluorescence quenching despite a low molar ratio of BODIPY-FL-glycophorin A . Proteolysis of the membrane protein causes greatly enhanced fluorescence which is used for a rapid one-step proteolysis assay . Direct monitoring of proteolysis in microcuvettes, or routine assay in microtiter plates can be used . Reproducibility is higher than with the radiolabeled substrate and the K(m) values for the two substrates are similar . The assay is suitable for the O-sialoglycoprotein endopeptidase activity of chromatographically purified enzyme or unpurified bacterial culture supernatants and can be used to monitor inhibition of the O-sialoglycoprotein endopeptidase by neutralizing antibodies . The O-sialoglycoprotein endopeptidase assay employing BODIPY-FL-glycophorin A provides a rapid and nonradioactive method for the assay of this highly specific enzyme.

Microb Pathog, 1998 Apr, 24(4), 203 - 9
Transposon Tn916 insertional mutagenesis of Pasteurella multocida and direct sequencing of disruption site; DeAngelis PL; The transposon Tn916, when introduced into Pasteurella multocida by electroporation on a nonreplicating plasmid, integrates into the bacterial chromosome . Efficiencies of approximately 8x10(4) mutants/microg of plasmid DNA were obtained . Restriction digestion and Southern analysis indicate that the Tn916 element integrates in a quasi-random fashion throughout the genome . Most transformants had a single copy of the transposon but approximately 5% had two copies . Furthermore, the nucleotide sequence at the disruption site of any desired mutant was obtained by capitalizing on the differential sensitivity of the transposon and the genome to the restriction enzyme HhaI; molecular cloning or amplification by polymerase chain reaction was not required . The Tn916 element has a single HhaI site . On the other hand, this restriction enzyme frequently cleaves the P . multocida chromosome with the vast majority of the resulting genomic fragments being less than 7 kb in length . Tn916 integration adds a 12 kb segment to the genomic HhaI fragment at the site of disruption . The resulting chimeric DNA fragment was isolated on the basis of size from digests of mutant genomic DNA separated on agarose gels . DNA sequencing with primers corresponding to the terminus of the Tn916 element was used to determine the sequence at the disruption site . In summary, Tn916 can be used to disrupt and to clone genes of P . multocida in a rapid and facile fashion .

Infect Immun, 1998 Jun, 66(6), 2836 - 44
Pasteurella haemolytica A1-derived leukotoxin and endotoxin induce intracellular calcium elevation in bovine alveolar macrophages by different signaling pathways; Hsuan SL et al.; Leukotoxin and endotoxin derived from Pasteurella haemolytica serotype 1 are the primary virulence factors contributing to the pathogenesis of lung injury in bovine pneumonic pasteurellosis . Activation of bovine alveolar macrophages with endotoxin or leukotoxin results in the induction of cytokine gene expression, with different kinetics (H . S . Yoo, S . K . Maheswaran, G . Lin, E . L . Townsend, and T . R . Ames, Infect . Immun . 63:381-388, 1995; H . S . Yoo, B . S . Rajagopal, S . K . Maheswaran, and T . R . Ames, Microb . Pathog . 18:237-252, 1995) . Furthermore, extracellular Ca2+ is required for leukotoxin-induced cytokine gene expression . However, the involvement of Ca2+ in endotoxin effects and the precise signaling mechanisms in the regulation of intracellular Ca2+ by leukotoxin and endotoxin are not known . In fura-2-acetoxymethyl ester-loaded alveolar macrophages, intracellular Ca2+ regulation by leukotoxin and endotoxin was studied by video fluorescence microscopy . Leukotoxin induced a sustained elevation of intracellular Ca2+ in a concentration-dependent fashion by influx of extracellular Ca2+ through voltage-gated channels . In the presence of fetal bovine serum, endotoxin elevated intracellular Ca2+ even in the absence of extracellular Ca2+ . Leukotoxin-induced intracellular Ca2+ elevation was inhibited by pertussis toxin, inhibitors of phospholipases A2 and C, and the arachidonic acid analog 5,8,11,14-eicosatetraynoic acid . Intracellular Ca2+ elevation by endotoxin was inhibited by inhibitors of phospholipase C and protein tyrosine kinase, but not by pertussis toxin, or the arachidonic acid analog . To the best of our knowledge, this is the first report of Ca2+ signaling by leukotoxin through a G-protein-coupled mechanism involving activation of phospholipases A2 and C and release of arachidonic acid in bovine alveolar macrophages . Ca2+ signaling by endotoxin, on the other hand, involves activation of phospholipase C and requires tyrosine phosphorylation . The differences in the Ca2+ signaling mechanisms may underlie the reported temporal differences in gene expression during leukotoxin and endotoxin activation.

Eur Radiol, 1998, 8(4), 588 - 91
Granulomatous hepatitis in pasteurella multocida infection; Chateil JF et al.; Numerous diseases can lead to multilocular lesions of the liver . The authors report a rare pediatric case of hepatic granulomas due to Pasteurella multocida: a 7-year-old girl with chronic fever was investigated by sonography and CT scan, demonstrating mesenteric lymph node enlargement and numerous small hepatic lesions . After surgical biopsy, histopathology of the liver specimens showed pyogenic granuloma, with serologic testing positive for Pasteurella multocida . Treatment with a tetracycline and corticosteroids was successful . Pasteurella multocida infection, despite its habitual benign course, should be suspected among differential diagnoses of lymphogranulomatous affections with hepatic involvement . No case of liver and lymph node foci in a child has been previously described.

South Med J, 1998 May, 91(5), 484 - 6
Hemoptysis as the sole presentation of Pasteurella multocida infection; Sazon DA et al.; Pasteurella multocida has been implicated as the cause of a variety of respiratory conditions (eg, bronchitis, pneumonia, lung abscess, empyema), but hemoptysis has been noted only in conjunction with other lung conditions . We report a case in which hemoptysis was the sole manifestation of Pasteurella infection . The patient was a middle-aged man with severe obstructive lung disease and exposure to cats . Diagnosis was made by bronchoscopy and high-dose penicillin was required for resolution.

J Clin Microbiol, 1998 Apr, 36(4), 1096 - 100
Development of PCR assays for species- and type-specific identification of Pasteurella multocida isolates; Townsend KM et al.; Genomic subtractive hybridization of closely related Pasteurella multocida isolates has generated clones useful in distinguishing hemorrhagic septicemia-causing type B strains from other P . multocida serotypes . Oligonucleotide primers designed during the sequencing of these clones have proved valuable in the development of PCR assays for rapid species- and type-specific detection of P . multocida and of type B:2 in particular . This study demonstrated that the primer pair designed from the sequence of the clone 6b (KTT72 and KTSP61) specifically amplified a DNA fragment from types B:2, B:5, and B:2,5 P . multocida and that the primers KMT1T7 and KMT1SP6 produced an amplification product unique to all P . multocida isolates analyzed . It was also shown that PCR amplification performed directly on bacterial colonies or cultures represents an extremely rapid, sensitive method of P . multocida identification.

Vet Rec, 1998 Apr 18, 142(16), 428 - 31
Efficacy of intranasal administration of formalin-killed Pasteurella haemolytica A2 against intratracheal challenge in goats; Effendy AW et al.; A trial was conducted to compare the efficacy of intranasal vaccination in protecting goats against pneumonic pasteurellosis with intramuscular vaccination using an oil adjuvant vaccine, and a combination of the two methods . Forty goats were divided into four equal groups . Group 1 was vaccinated twice intranasally with formalin-killed Pasteurella haemolytica A2, group 2 was vaccinated twice intramuscularly with an oil adjuvant vaccine containing P haemolytica A7, and group 3 was initially vaccinated intranasally with the formalin-killed P haemolytica A2 followed by intramuscular vaccination with the oil adjuvant vaccine . In each group the two vaccinations were carried out four weeks apart . Group 4 was the unvaccinated control group . All goats were challenged intratracheally with 4 ml of an inoculum containing live P haemolytica A2 at a concentration of 1.3 x 10(7) colony forming units/ml two weeks after the last vaccination and were killed 14 days after the challenge . Although group 2 showed the highest clinical score following the challenge, deaths were observed only in group 3 . Three goats in group 1 had pneumonic lung lesions, compared with six goats in group 2 and all the goats in groups 3 and 4 . The lung lesions in group 1 were significantly (P < 0.05) less severe than in groups 3 and 4 . Similarly, the lesions in group 2 were markedly less severe than in groups 3 and 4, although the differences were not significant . The difference between the extent of the lung lesions in the goats in groups 1 and 2 was not significant . Antibody against P haemolytica A2 in group 1 reached peak levels and was significantly (P < 0.01) higher than in the control group one week after the second vaccination, before declining.

Vet Microbiol, 1998 Feb 15, 60(1), 67 - 73
Characterization of a 54-kDa heat-shock-inducible protein of Pasteurella haemolytica; Mosier D et al.; Growth-condition-dependent antigens play a role in the virulence or protective capacity of many organisms . Enhanced production of an approximately 54-kDa protein was detected in heat-shocked cultures of Pasteurella haemolytica . The heat-shock-inducible protein cross-reacted with antibodies to 60-kDa heat-shock proteins of Mycobacterium tuberculosis, Chlamydia, and Escherichia coli GroEL . A probe containing the E . coli groEL operon hybridized with fragments of P . haemolytica chromosomal DNA on Southern blots . Immunoblots of the 54-kDa protein using serum from 20 calves that were challenged experimentally with P . haemolytica resulted in band densities that were significantly different between calves with high and low lesion scores . Results of the study suggest that the 54-kDa heat-shock protein may be a growth-condition-dependent immunogen that is one component of resistance to pneumonic pasteurellosis.

Am J Vet Res, 1998 May, 59(5), 588 - 92
In vivo effect of Pasteurella haemolytica infection on bovine neutrophil morphology; Clarke CR et al.; OBJECTIVE: To determine whether characteristic changes in neutrophil morphology caused in vitro by Pasteurella haemolytica leukotoxin (LKT) can be observed in vivo by electron microscopic examination of infected tissue chamber fluids and pneumonic lungs . ANIMALS: 7 mixed-breed beef calves . PROCEDURE: Tissue chambers were implanted subcutaneously in 3 calves and were inoculated with P haemolytica or phosphate-buffered saline solution . Chamber fluid samples, obtained at 8 and 32 hours after inoculation, were examined, using electron microscopy . Experimental pneumonia was induced in an additional 4 calves by transthoracic inoculation with P haemolytica . These calves were euthanatized at 6, 12, 24, and 36 hours after inoculation and lung sections were examined, using transmission electron microscopy . RESULTS: On examination, using transmission electron microscopy, neutrophils in lung sections and tissue chamber fluids had cytoplasmic and nuclear changes indicative of irreversible cell injury, including cell swelling, loss of plasma membrane ruffling, mitochondrial swelling, autolytic vacuolation, disruption of plasma membrane, nuclear pyknosis, karyolysis, and karyorrhexis . On examination, using scanning electron microscopy, leukocytes obtained from tissue chambers did not have their typical convoluted surfaces, but appeared rounded and swollen or shrunken with pitted surfaces . CONCLUSIONS: Pasteurella haemolytica-induced changes in neutrophil morphology in vivo were similar to those previously induced by in vitro exposure of neutrophils to LKT . Changes were suggestive of injury initiated by damage to the plasma membrane, which is consistent with the mechanism of action of pore-forming cytolysins . CLINICAL RELEVANCE: Pasteurella haemolytica LKT appears to be an important virulence factor in vivo; a fact that should be addressed in the development of vaccines.

Clin Nephrol, 1998 Apr, 49(4), 258 - 61
Pasteurella multocida peritonitis in peritoneal dialysis; Musio F et al.; Pasteurella multocida infection may occur in multiple sites to include rare involvement of the peritoneal cavity in peritoneal dialysis patients . Six cases of peritonitis associated with this organism have been reported in patients undergoing continuous peritoneal dialysis . A history of close contact with household cats was noted in all cases, with direct trauma to the dialysis tubing frequently seen . In this setting the organism appears to have a short incubation period with florid growth within 24 hours of known contamination . We report a case of Pasteurella multocida peritonitis in a patient treated with continuous cycling peritoneal dialysis and review the literature.

Berl Munch Tierarztl Wochenschr, 1998 Mar, 111(3), 90 - 2
{Protein patterns of Pasteurella multocida strains in relation to the animal host and the geographic site of isolation}; Grossmann E et al.; Protein patterns from 681 Pasteurella multocida strains of different animal species and distinct geographical regions were analyzed by PAGE . We found 9 protein types taking the most intense band as reference . This band represents a protein of the outer membrane (OMP) . In assigning the strains to protein types a relation to animal hosts of the strains was established . The majority of isolates from rabbits (88%) belongs to type P6, which is not found in strains isolated from cattle or pigs . Strains from pigs did not include the protein types P2, P4 and P8, in cattle strains type P9 was absent . The distribution of protein types in bovine isolates was shown to be related to the geographical location . The results are discussed with particular emphasis on immuno-prophylaxis . It appears promising to develop P . m . vaccines specific for certain animal species.

Curr Microbiol, 1998 May, 36(5), 274 - 7
Relationship between serotype A encapsulation and a 40-kDa lipoprotein in Pasteurella multocida; Ryals PE et al.; Eleven serotype A encapsulated and nonencapsulated strains of Pasteurella multocida were examined with regard to lipoprotein content . Relative amounts of an approximately 40-kDa lipoprotein (Plp-40) were found to correlate directly with the degree of encapsulation in that heavily encapsulated strains exhibited the greatest amounts, while nonencapsulated strains possessed little or no Plp-40.

Eur J Biochem, 1998 Apr 1, 253(1), 309 - 18
Role of sialosyl Lewis(a) in adhesion of colon cancer cells--the antisense RNA approach; Klopocki AG et al.; To study whether the adhesion of colon cancer cells to E-selectin can be directly affected by changes in the expression level of sialosyl Le(a) antigen we created a specific loss-of-function phenotype . A stable subclone (CX-1.1) with high expression of sialosyl Le(a) structure, obtained from a heterogenous population of colon carcinoma CX-1 cells, was transfected with an expression vector containing a fragment of cDNA for alpha1,3/4-fucosyltransferase in antisense orientation . After transfection, the cell line was isolated which did not express sialosyl Le(a) antigen and lacked the alpha1,3/4-fucosyltransferase activity, despite an unchanged level of mRNA specific for this enzyme . It was found that the specific lack of expression of sialosyl Le(a) carbohydrate structure on the surface of colon cancer cells completely abolished their adhesion to E-selectin . To evaluate which cellular glycoconjugates carry sialosyl Le(a) antigen, glycoproteins as well as glycolipids of CX-1.1 cells were analysed for the expression of this structure . Anti-sialosyl Le(a) antibodies detected multiple glycoprotein bands with apparent molecular masses of 65-280 kDa on western blots, and an intense band representing sialosyl Le(a)-ganglioside on a thin-layer chromatogram . Using O-sialoglycoprotease from Pasteurella haemolytica and an alkaline beta-elimination procedure, it was shown that protein-linked sialosyl Le(a) structures are carried mostly by mucin-type glycoproteins . However, treatment of CX-1.1 cells with O-sialoglycoprotease did not decrease either their binding to E-selectin-expressing Chinese hamster ovary cells, or binding of anti-sialosyl Le(a) antibodies to the cell surface . These results suggested that cleavage of sialomucins uncovered cryptic sialosyl Le(a)-ganglioside, which was inaccessible for the antibody and E-selectin in untreated cells . This hypothesis was confirmed to some extent by the higher accessibility of gangliosides to galactose oxidase on the surface of O-sialoglycoprotease-treated CX-1.1 cells, comparing to untreated cells . We propose that glycoproteins as well as gangliosides carrying sialosyl Le(a) structures, when properly exposed and present in high density on surface of cancer cells, can effectively support the adhesion of cancer cells to E-selectin.

J Wildl Dis, 1998 Apr, 34(2), 348 - 54
Northern bobwhites as disease indicators for the endangered Attwater's prairie chicken; Purvis JR et al.; Because of limited access to the endangered Attwater's prairie chicken (Tympanuchus cupido attwateri), we used a related species, the northern bobwhite (Colinus virginianus), as a surrogate for disease evaluation . Free-living northern bobwhites (n = 62) on the Attwater Prairie Chicken National Wildlife Refuge (near Eagle Lake, Texas, USA) were examined during spring and fall 1993 for helminthic endoparasites and specific antibodies against the infectious agents responsible for nine infectious diseases . Trichostrongylus cramae, Raillietina sp., and Strongyloides avium were collected from 97, 44, and 32% of northern bobwhites examined, respectively . Dispharynx nasuta and Syngamus trachea also were found . No gross lesions due to parasites were observed . Specific antibody to Pasteurella multocida was found in 3 of 53 plasma samples . It is possible that potentially pathogenic species such as P . multocida, T . cramae, and D . nasuta could threaten sympatric Attwater's prairie chickens.

J Wildl Dis, 1998 Apr, 34(2), 325 - 33
Evaluation of a multivalent Pasteurella haemolytica vaccine in bighorn sheep: protection from experimental challenge; Kraabel BJ et al.; The efficacy of a multivalent Pasteurella haemolytica vaccine (A1, A2, T10) in reducing morbidity and mortality associated with pneumonic pasteurellosis in bighorn sheep (Ovis canadensis) was examined . Fifteen captive bighorns were divided equally into three treatment groups based on vaccination status: control (no vaccination), one dose 10 days prior to challenge, or one or two doses 57 wk prior to challenge . At challenge, each bighorn received about 6.2 x 10(7) colony forming units of P . haemolytica (biotype T, serotype 10, biogroup 4-CDS; ribotype ECO; "Alamosa Canyon" strain) suspension sprayed into the proximal trachea . Vaccination reduced (P = 0.1) mortality in bighorns vaccinated 10 days prior to challenge as compared to controls . Although mortality rates in bighorns vaccinated 57 wk prior to challenge did not differ from controls (P = 0.26), a trend in reduced mortality was apparent . Ranked cumulative postmortem scores based on observed gross lesions and bacteriology did not differ (P > or = 0.14) between vaccinated animals and control animals . Neutralizing antibody titers to P . haemolytica leukotoxin were elevated (P = 0.003) at challenge in bighorns vaccinated 10 days before challenge, and neutralizing titers in bighorns from both vaccinated groups were elevated at death < or = 7 days after challenge (P < or = 0.004) . In contrast, agglutinating antibody titers to P . haemolytica serotype A1 or T10 surface antigens did not differ between vaccinated and unvaccinated bighorns (P > or = 0.19) . Based on these data, we believe that this experimental P . haemolytica vaccine is safe and can stimulate protective immunity from pneumonic pasteurellosis in bighorn sheep . Further evaluation of this vaccine as a tool in preventing and managing pasteurellosis in wild bighorn sheep appears warranted.

J Vet Diagn Invest, 1998 Apr, 10(2), 169 - 73
Evaluation of techniques for the detection of toxigenic Pasteurella multocida strains from pigs; Amigot JA et al.; Recently acquired field isolates and archived isolates from our collection of Pasteurella multocida were analyzed for production of dermonecrotic toxin . Detection of the toxin was carried out using a fetal lung feline (FLF) cell line and a commercial enzyme-linked immunosorbent assay (ELISA) kit . The dermonecrotic toxin gene (ToxA) was also detected using a polymerase chain reaction (PCR) technique . Results from the 3 methods were compared . Field isolates (group 1) came from a commercial herd that had clinical signs of atrophic rhinitis . Fifty-six (17.9%) strains were isolated from 312 nasal swabs . Thirty-five of these strains belonged to serotype A and the rest (21/56), although probably serotype D, were not characterized further . All of these strains were toxin negative based on both the ELISA and FLF cell culture results . Five isolates gave faint bands in the PCR reaction, and the rest (51/56) were PCR negative . PCR and ELISA were also performed from the initial swab cultures (mixed cultures); 7 samples gave faint PCR bands, but ELISA results were all negative . Archived strains (group 2) had been isolated from clinical cases of atrophic rhinitis and from cases of pulmonary pasteurellosis . A total of 76 strains were analyzed; 46 were serotype A, and the rest (30) were serotype D . ELISA and FLF cell culture tests were negative for all serotype A strains; however, 3 strains showed faint bands in the PCR reaction . Fourteen serotype D strains showed positive results in both the ELISA and the FLF cell culture tests . PCR from these samples also gave positive results showing a strong band in the gel . However, 4 strains that were ELISA and FLF cell culture negative showed a faint band in the PCR reaction . The 3 methods gave similar results in the detection of the P . multocida dermonecrotic toxin . However, complete agreement among the tests was achieved only when strong PCR bands were considered positive . This is the first report that demonstrates the use of FLF cell line for the detection of toxigenic P . multocida.

J Vet Diagn Invest, 1998 Apr, 10(2), 164 - 8
Evaluation of a computerized antimicrobial susceptibility system with bacteria isolated from animals; Hubert SK et al.; The BIOMIC is a computerized system used to calculate the minimal inhibitory concentration (MIC) of an antimicrobial agent from a zone of inhibition generated by a disk diffusion test . This system was developed using bacterial pathogens of human origin . This study investigated the use of the BIOMIC system for determining MICs for bacterial pathogens from animals . The MICs generated by the BIOMIC system were compared with the MICs generated using a broth microdilution testing method . A total of 663 drug-organism combinations was tested . These combinations included 3 species of gram-positive bacteria, 5 species of gram-negative bacteria, and the antimicrobial agents ampicillin, gentamicin, cephalothin, ciprofloxacin, enrofloxacin, trimethoprim/sulfamethoxazole, tetracycline, and erythromycin . Overall, the MICs generated by the BIOMIC system correlated with the broth microdilution MICs for 72% of the total drug-organism combinations tested . The Pseudomonas aeruginosa strains tested showed the highest agreement between the 2 systems, with 100% for all antibacterial agents tested, whereas Pasteurella haemolytica, Pasteurella multocida, and enterococci showed the least agreement (76%, 57%, and 47%, respectively) . Among these organisms, trimethoprim-sulfa showed the least agreement (31%) and ciprofloxacin showed the greatest (91%) . These results indicate that the BIOMIC system could be a useful tool in veterinary medicine for producing quantitative antimicrobial susceptibility results . However, it is currently unreliable for some drug-bacteria combinations . This discrepancy possibly could be corrected by modification of the software using data points generated by a large-scale study.

J Clin Microbiol, 1998 May, 36(5), 1260 - 5
Effects of ammonia inhalation and acetic acid pretreatment on colonization kinetics of toxigenic Pasteurella multocida within upper respiratory tracts of swine; Hamilton TD et al.; Pigs reared in intensive production systems are continuously exposed to ammonia released by the microbial degradation of their excrement . Exposure to this gas has been shown to increase the severity of the disease progressive atrophic rhinitis by facilitating colonization of the pig's upper respiratory tract by Pasteurella multocida . The etiological mechanism responsible for this synergy was investigated by studying the colonization kinetics of P . multocida enhanced by ammonia and comparing them with those evoked by an established disease model . Three-week-old Large White piglets were weaned and allocated to five experimental groups (groups A to E) . Pigs in groups A and B were exposed continuously to ammonia at 20 ppm for the first 2 weeks of the study . Pigs in group C were pretreated with 0.5 ml of 1% acetic acid per nostril on days -2 and -1 of the study . On day 0 all the pigs in groups A, C, and D were inoculated with 1.4 x 10(8) toxigenic P . multocida organisms given by the intranasal route . The kinetics of P . multocida colonization were established by testing samples obtained at weekly intervals throughout the study . The study was terminated on day 37, and the extent of turbinate atrophy was determined by using a morphometric index . The results of the study showed that exposure to aerial ammonia for a limited period had a marked effect on the colonization of toxigenic P . multocida in the nasal cavities of pigs, which resulted in the almost total exclusion of commensal flora . In contrast, ammonia had only a limited effect on P . multocida colonization at the tonsil . The exacerbation of P . multocida colonization by ammonia was restricted to the period of ammonia exposure, and the number of P . multocida organisms colonizing the upper respiratory tract declined rapidly upon the cessation of exposure to ammonia . During the exposure period, the ammonia levels in mucus recovered from the nasal cavity and tonsil were found to be 7- and 3.5-fold higher, respectively, than the levels in samples taken from unexposed controls . Acetic acid pretreatment also induced marked colonization of the nasal cavity which, in contrast to that induced by ammonia, persisted throughout the time course of the study . Furthermore, acetic acid pretreatment induced marked but transient colonization of the tonsil . These findings suggest that the synergistic effect of ammonia acts through an etiological mechanism different from that evoked by acetic acid pretreatment . A strong correlation was found between the numbers of P . multocida organisms isolated from the nasal cavity and the severity of clinical lesions, as determined by using a morphometric index . The data presented in the paper highlight the potential importance of ammonia as an exacerbating factor in respiratory disease of intensively reared livestock.

J Comp Pathol, 1998 Feb, 118(2), 163 - 7
Changes in the lungs of lambs after intratracheal injection of lipopolysaccharide from Pasteurella haemolytica A1; Cutlip RC et al.; Ten lambs aged 8 weeks were inoculated intratracheally through the tracheal wall with lipopolysaccharide from Pasteurella haemolytica A1 and examined in chronological sequence by light and electron microscopy for pulmonary lesions . An acute fibrinopurulent pneumonia was produced, which resolved within 72 h but bore many resemblances to field cases of pneumonic pasteurellosis . Sequestration of neutrophils in the capillaries of the lungs and aggregation of surfactant in the alveoli occurred rapidly, followed by swelling of the alveolar and capillary endothelia, oedema, haemorrhage, and emigration of neutrophils into the interstitium and small air spaces of the lungs . Necrosis of isolated neutrophils was a constant feature . Alveolar, interstitial and intravascular macrophages and lymphoid cells increased slowly to become the predominant inflammatory cells at 72 h . A surprising feature was the transient appearance of multinucleated cells in the lungs at 2 and 6 h after inoculation . It is concluded that lipopolysaccharide makes a major contribution to the pathogenesis of P . haemolytica infection in the lungs of sheep.

Infect Immun, 1998 May, 66(5), 1885 - 90
Pasteurella haemolytica leukotoxin-induced increase in phospholipase A2 activity in bovine neutrophils; Wang Z et al.; Exposure of bovine neutrophils to Pasteurella haemolytica leukotoxin (LKT) stimulates the production of leukotriene B4 (LTB4), which is believed to be an important chemotactic agent in the development of acute fibrinopurulent pneumonic infection in cattle . The involvement of phospholipase A2 (PLA2) in LKT-induced synthesis of LTB4 was studied by using bovine neutrophils labeled with 3H-arachidonate ({3H}AA) . Incubation of isolated neutrophils with {3H}AA resulted in incorporation of radioactivity in the PLA2 substrates phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine . Exposure of radiolabeled neutrophils to LKT caused concentration- and time-dependent release of radioactivity and redistribution of radioactivity in neutrophil membranes consistent with utilization of phosphoglyceride substrate and release of free fatty acid and eicosanoid products . These LKT-induced effects could be inhibited by pretreatment with arachidonyl trifluoromethyl ketone, an inhibitor of type IV cytoplasmic PLA2, and were dependent on extracellular calcium . These results support the conclusion that LKT-induced synthesis of LTB4 involves a calcium-mediated increase in PLA2 activity.

J Biol Chem, 1998 Apr 3, 273(14), 8454 - 8
Identification and molecular cloning of a unique hyaluronan synthase from Pasteurella multocida; DeAngelis PL et al.; Type A Pasteurella multocida, a prevalent animal pathogen, employs a hyaluronan {HA} polysaccharide capsule to avoid host defenses . We utilized transposon insertional mutagenesis to identify the P . multocida HA synthase, the enzyme that polymerizes HA . A DNA fragment from a wild-type genomic library could direct HA production in vivo in Escherichia coli, a bacterium that normally does not produce HA . Analysis of truncated plasmids derived from the original clone indicated that an open reading frame encoding a 972-residue protein was responsible for HA polymerization . This identification was confirmed by expression cloning in E . coli; we observed HA capsule formation in vivo and detected activity in membrane preparations in vitro . The polypeptide size was verified by photoaffinity labeling of the native P . multocida HA synthase with azido-UDP sugar analogs . Overall, the P . multocida sequence is not very similar to the other known HA synthases from streptococci, PBCV-1 virus, or vertebrates . Instead, a portion of the central region of the new enzyme is more homologous to the amino termini of other bacterial glycosyltransferases that produce different capsular polysaccharides or lipopolysaccharides . In summary, we have discovered a unique HA synthase that differs in sequence and predicted topology from the other known enzymes.

Parasite Immunol, 1998 Mar, 20(3), 121 - 34
Induction of CD4+CD8+ double positive T cells and increase in CD5+ B cells in efferent lymph in sheep infected with Trypanosoma evansi; Onah DN et al.; The effects of Trypanosoma evansi on efferent lymphocyte phenotypes draining from a lymph node primed with Pasteurella haemolytica vaccine were studied in sheep . The prefemoral efferent lymphatic ducts of the infected sheep along with those of two uninfected sheep were surgically cannulated . Lymph was collected and lymphocytes recovered from it analysed by two-colour indirect immunofluorescence staining and cytofluoremetry in a fluorescence activated cell analyser (FACSCAN) . The study showed the appearance and persistence of T . evansi in the efferent lymph for a long period of time and the appearance of CD4+CD8+ (double positive, DP) T lymphocytes in the efferent lymph of infected animals . The infection also resulted in increases in CD5+ B cells in the prefemoral efferent lymph . In addition, there were decreases in the output of conventional B cells, CD5+ and CD4+ T cell subsets but large increases in CD8+ cells followed by terminal depletion of all cell subsets . In contrast, inoculation of sheep with pasteurella vaccine antigen alone produced little alterations in the proportions, but large increases in the numbers of all T cell subsets except that of CD8+ cells which also showed little variation; and there was a concurrent increase in the numbers and proportions of efferent B cells . In addition, the abnormal expression of DP and CD5+ B cells did not occur in the uninfected vaccinated sheep . It is concluded that these abnormal changes in the kinetics of efferent lymphocyte phenotypes are likely to play a role in the genesis of the generalized immunosuppression seen in trypanosome-infected hosts.

Am J Vet Res, 1998 Apr, 59(4), 426 - 30
Development and testing of a unique strain of Pasteurella haemolytica for use in studies on colonization of the respiratory tract of cattle; Briggs RE et al.; OBJECTIVE: To develop a unique strain of Pasteurella haemolytica, selectable from nasopharyngeal respiratory tract secretions, that retains the ability to efficiently colonize the respiratory tract of calves . ANIMALS: 26 calves that each weighed approximately 200 kg . PROCEDURE: Rifampicin-resistant mutants of P haemolytica were developed and tested for in vitro growth rate and leukotoxin production . After instillation into the tonsils of calves, an isolate that was efficient at colonizing was selected and transformed, using electroporation, with a 4.2-kilobase (kb) plasmid encoding for streptomycin resistance . This isolate was instilled into the tonsils of 4 of 14 commingled calves to examine transmission of organisms . Nasal secretion and tonsil wash specimens were collected, cultured, and examined for P haemolytica . Serum antibody concentration was measured by means of indirect hemagglutination . RESULTS: Selected P haemolytica organisms colonized the tonsils and nasal passages for more than 2 weeks . Exposed calves and contact calves shed the organism, which was recovered from specimens of nasal secretions and tonsil washes . The 4.2-kb plasmid was lost during in vivo colonization . CONCLUSIONS AND CLINICAL RELEVANCE: The selected rifampicin-resistant P haemolytica organism colonized tonsils and nasal passages in a manner similar to the wild-type organisms . Selective media suppressed other bacterial flora to the extent that a single colony-forming unit was detectable from 200 microl of specimen, a 100-fold improvement in detection sensitivity . The selectable strain spread rapidly among commingled calves . A 4.2-kb plasmid marker was unstable when P haemolytica replicated in vivo.

Am J Vet Res, 1998 Apr, 59(4), 401 - 5
Rapid spread of a unique strain of Pasteurella haemolytica serotype 1 among transported calves; Briggs RE et al.; OBJECTIVE: To determine the rate and mode of infectious spread of Pasteurella haemolytica among calves maintained under typical conditions during collection, transport, and the first month of feeding . ANIMALS: 101 two- to five-month-old Angus-crossbred calves . PROCEDURE: Samples obtained from cattle prior to and after they were transported to a feedlot were used for isolation and characterization of P haemolytica . Samples were also obtained from additional calves, some of which were sick, and these calves were then commingled with the transported calves for 3 days . A strain of P haemolytica that contains a rare deletion of the 4.2-kilobase streptomycin- and sulfonamide-resistance plasmid was inoculated into both palatine tonsils of 12 calves . Nasal secretions were aspirated from the ventral nasal meatus . Tonsillar wash specimens were procured . Pasteurella haemolytica organisms were quantitatively cultured and identified on the basis of colony morphology and response to specific antisera . Plasmids were isolated by an alkaline lysis procedure and identified by agarose gel electrophoresis . RESULTS: A single plasmid profile was observed from P haemolytica isolated from samples obtained prior to shipment . Commingled calves were shedding P haemolytica containing each known plasmid profile . After shipment, samples contained P haemolytica isolates with each known plasmid profile . The plasmid profile of the unique P haemolytica isolate was recovered from all 12 inoculated calves and 10 other calves . Some calves simultaneously shed P haemolytica isolates with differing plasmid profiles . CONCLUSIONS AND CLINICAL RELEVANCE: Pasteurella haemolytica serotype 1 was horizontally transmitted among calves within days of commingling, which continued after calves were transported to a feedlot.

J Vet Med Sci, 1998 Mar, 60(3), 301 - 5
Pasteurella multocida toxin and Bordetella bronchiseptica dermonecrotizing toxin elicit similar effects on cultured cells by different mechanisms; Ohnishi T et al.; We compared the effects of Pasteurella multocida toxin (PMT) with Bordetella bronchiseptica dermonecrotizing toxin (DNT) at a cellular level under same conditions . Both PMT and DNT cause actin stress fiber formation in MC3T3-E1 cells which is known to be regulated by the small GTP-binding protein Rho . DNT induced mobility shifts of Rho on SDS-polyacrylamide gel electrophoresis, indicating direct modification as reported elsewhere . In contrast, no alternations in the electrophoretic mobility of Rho were found in lysates from PMT-treated cells . PMT but not DNT increased the intracellular level of inositol phosphates, indicating the elevation of phospholipase C (PLC) activity in the PMT-treated cells . These results indicate that PMT does not have Rho as a target but activates PLC . The formation of actin stress fiber by PMT seems to be stimulated through the indirect activation of Rho, which resides downstream of PLC, PMT and DNT seem to elicit similar toxic effects, at least in part, through the activation of Rho.

Vet Microbiol, 1998 Jan 31, 59(4), 295 - 307
Development of a PCR test based on a gene region associated with the pathogenicity of Pasteurella multocida serotype B:2, the causal agent of haemorrhagic septicaemia in Asia; Brickell SK et al.; We have developed a PCR assay to detect Pasteurella multocida serotype B:2, the causal agent of Haemorrhagic Septicaemia (HS) in Asia . Nucleotide sequence determination of a 16S rRNA-23S rRNA PCR product unique to B:2 strains was shown to share amino acid sequence homology with a bacteriophage Mu protein . Primers designed from this sequence when tested against a panel of isolates recovered from a wide geographical area and representing a large range of bacterial genera and species, were found to specifically amplify DNA from P . multocida, serotype B:2 . Southern hybridisation confirmed the presence of this sequence in only the B:2 serotype of P . multocida, suggesting an association between bacterial virulence and the presence of bacteriophage genes in the bacterial genome . The results of this study demonstrate the potential application of PCR to the diagnosis of HS in cattle and buffalo in Asia . Application of PCR to support diagnosis of HS will greatly improve accuracy, laboratory response time, and will facilitate rational deployment of resources for controlling this disease.

Dev Biol Stand, 1998, 92, 301 - 7
Immunity provided by haemorrhagic septicaemia-subunit vaccine in ruminants; Maslog FS; A subunit vaccine against haemorrhagic septicaemia (HS), the principal killer disease in ruminants, especially cattle and carabao, in the Philippines, has been developed . Using capsules of Pasteurella multocida Group B as an active component of the vaccine, it gave solid protection against challenge with live organism in mice . An active calf protection test showed that in 24 hours, animals vaccinated with plain saline died after challenge compared to those given the subunit vaccine which survive the challenge dose . Using 104 cattle from a farm, the field trial of the HS subunit vaccine showed that the antibody titre was high for up to 14 months . A high titer is an indication of protection.

Diagn Microbiol Infect Dis, 1998 Feb, 30(2), 99 - 102
In vitro activity of oral antimicrobial agents against clinical isolates of Pasteurella multocida; Mortensen JE et al.; Pasteurella multocida causes a wide variety of infections and is the most common localized soft tissue infection after animal bite injuries . Penicillin or amoxicillin has been considered agent of choice for therapy . Reported beta-lactamase production by some isolates, the therapeutic dilemma of the penicillin allergic patient, and the polymicrobial nature of some infections led to this study of alternate antimicrobial agents . The in vitro activity of ampicillin, amoxicillin/clavulanate, cefprozil, cefuroxime, erythromycin, clarithromycin, trimethoprim/sulfamethoxazole, ciprofloxacin, and tetracycline were compared to penicillin against 73 geographically diverse isolates of P . multocida from human infections collected since 1991 . MIC90 (microgram/mL) were as follows: penicillin < or = 0.06; ampicillin < or = 0.5; amoxicillin/clavulanate < or = 0.5; cefaclor 1.0; cefprozil 1.0; cefpodoxime 0.06; cephalothin 2.5; cefuroxime < or = 0.25; erythromycin 2.0; azithromycin 1.0; clarithromycin 4.0; trimethoprim/sulfamethoxazole < or = 0.5/9.5; ciprofloxacin < or 0.25; tetracycline < or = 2.0 . No beta-lactamase producing isolates were found in this study . This in vitro study has identified alternate oral agents to penicillins that may be appropriate for therapy of P . multocida infections.

J Antibiot (Tokyo), 1998 Feb, 51(2), 136 - 44
In vitro microbiological characterization of novel macrolide CP-163,505 for animal health specific use; Norcia LJ et al.; A novel 16-membered-ring macrolide agent (CP-163,505, a reductive amination derivative of repromicin) was identified as an antibacterial against Pasteurella haemolytica, P . multocida and Actinobacillus pleuropneumoniae, important etiological agents of livestock respiratory disease . In vitro MIC50/90 analysis revealed that CP-163,505 was more potent (4x) than tilmicosin against P . multocida, and equivalent to tilmicosin against P . haemolytica and A . pleuropneumoniae . In time kill kinetic studies, CP-163,505 showed bactericidal activity against P . haemolytica, P . multocida and A . pleuropneumoniae and bacteriostatic activity against E . coli at 8 times its MIC . In vitro, CP-163,505 was more potent in alkaline pH (16 approximately 32 x ) and less potent in the presence of excess cations (Mg+2 and Ca+2, 4x) . EDTA and PMBN increased CP-163,505 potency against E . coli (4x) but not against the other species . Similar results were obtained with erythromycin A and tilmicosin, which were used as controls . From our data, we hypothesize that Pasteurella and Actinobacillus have an outer membrane significantly different from that of the typical enteric Gram-negative bacterium E . coli.

J Am Vet Med Assoc, 1998 Apr 1, 212(7), 1001 - 5
Assessment of spatial and temporal clustering of ampicillin- and tetracycline-resistant strains of Pasteurella multocida and P haemolytica isolated from cattle in California; Singer RS et al.; OBJECTIVE: To determine whether ampicillin- and tetracycline-resistant strains of Pasteurella multocida and P haemolytica isolated from California cattle with pneumonia were spatially and temporally clustered and to compare overall estimates of percentages of these isolates resistant to these antimicrobials with estimates obtained on the basis of regional and temporal information . DESIGN: Epidemiologic study . SAMPLE POPULATION: Records of P multocida and P haemolytica isolates obtained from lung or tracheal wash samples collected from California cattle with pneumonia between July 1, 1991 and July 31, 1996 . Only isolates obtained from samples submitted by dairies and calf ranches were used . PROCEDURE: Spatial clustering of ampicillin- and tetracycline-resistant isolates was assessed by use of nearest-neighbor and Cuzick and Edwards' analyses . Linear clustering along a north-south line was assessed by use of runs and maximum length of runs tests . Temporal clustering was assessed by use of scan tests . Spatial-temporal clustering was assessed by use of Barton's method . Regional estimates of percentages of P multocida and P haemolytica resistant to ampicillin or tetracycline were calculated . RESULTS: There was significant spatial clustering of resistant isolates and significant linear clustering along a north-south line . Significant differences in regional estimates of percentages of antimicrobial-resistant isolates were found . CLINICAL IMPLICATIONS: Results support the hypothesis that antimicrobial-resistant organisms can be clustered at the local level and reinforce the need to establish regional estimates of percentages of bacterial isolates that will be susceptible to commonly used antimicrobials.

Curr Microbiol, 1998 Apr, 36(4), 207 - 11
Cross-protection studies with three serotypes of Pasteurella haemolytica in the goat model; Purdy CW et al.; Cross-protection studies employing three serotypes of Pasteurella haemolytica (Ph) were performed in goats, with challenge exposure by transthoracic injection . Indirect hemagglutination (IHA) serum titers showed that the herd had been naturally infected with Ph biovar A, serovar 2 (PhA2) prior to the study . Sixty-four weanling male Spanish goats were randomly allotted to 16 groups . Fifteen goats were given two transthoracic injections into the lungs 21 days apart with live Pasteurella haemolytica biovar A, serovar 1 (PhA1) in agar beads . Fifteen goats were given two transthoracic injections into the lungs 21 days apart with live PhA2 in agar beads . Sixteen goats were given two transthoracic injections into the lungs 21 days apart with live P . haemolytica biovar A, serovar 6 (PhA6) in agar beads . Eighteen control (CON) goats were given two transthoracic injections into the lungs 21 days apart with agar beads alone . Fourteen days after the second injection, goats were challenge-exposed to either live PhA1, PhA2, or PhA6 by transthoracic injection into the lung, and 4 days later, all goats were euthanatized and necropsied . Serum antibody to P . haemolytica antigens was measured throughout the experiment . Mean volumes of consolidated lung tissue for the CON goats challenged with PhA1, PhA2, and PhA6 were 28.29 cm3, 8.36 cm3, and 16.29 cm3, respectively . Mean volumes of consolidated lung tissue for the PhA1-immunized goats challenged with PhA1, PhA2, and PhA6 were 4.38 cm3, 0.25 cm3, and 1.90 cm3, respectively . Mean volumes of consolidated lung tissue for the PhA2-immunized goats challenged with PhA1, PhA2, and PhA6 were 9.68 cm3, 0.05 cm3, and 3.39 cm3, respectively . Mean volumes of consolidated lung tissue for the PhA6-immunized goats challenged with PhA1, PhA2, and PhA6 were 14.05 cm3, 1.27 cm3, and 4.53 cm3, respectively . These data demonstrate protection in immunized goats challenged with the homologous serotype of P . haemolytica . PhA1-immunized animals were protected against serotype 2 challenge as well as against serotype 6 challenge . PhA2-immunized animals were not protected against serotype 1 challenge, but were protected against transthoracic PhA6 challenge . PhA6-immunized animals were not protected against serotype 1 challenge, but were protected against transthoracic PhA2 challenge . There appears to be some cross-protection among the P . haemolytica serotypes, and this fact should be taken into consideration when developing vaccines against this organism.

Avian Dis, 1998 Jan-Mar, 42(1), 204 - 8
Subacute to chronic fowl cholera in a flock of Pharaoh breeder quail; Miguel B et al.; A total of 1300 birds in flock of breeder Pharaoh quail (Coturinix coturnix) experienced a moderate rate of mortality (13%) during a 7-day period . Clinical signs included depression, ruffled feathers, prostration, lameness, inapetence, diarrhea, and periorbital sinus swelling with mucoid discharge and lameness . Gross lesions observed in dead quail were emaciation, carcass congestion, mild hepatomegaly with green discoloration, congested intestinal mucosa, caseous purulent arthritis-osteomyelitis, and thickened crop mucosal epithelium . Histopathologic examination revealed mild hepatic amyloidosis, proliferative parabronchitis, splenic reticular cell hyperplasia, thymic cortical atrophy, subacute bacterial osteomyelitis, periarthritis, and crop mycosis . Pasteurella multocida was isolated from the joints of these birds and the isolates were serotype 3 x 4 . These findings suggest that Pharaoh quail are susceptible to P . multocida and are likely to develop subacute to chronic fowl cholera.

Avian Dis, 1998 Jan-Mar, 42(1), 190 - 3
Pasteurella challenge and ELISA serology evaluation of broiler breeders vaccinated with live cholera vaccine; Sander JE et al.; Broiler breeder pullets were vaccinated against fowl cholera at 10 and 20 wk of age using a live PM-1 Pasteurella multocida vaccine administered by wing web stick . Antibody production for P . multocida was measured at vaccination and at 1-4-wk intervals following vaccination by enzyme-linked immunosorbent assay . Groups of vaccinated birds were challenged at 23 and 32 wk of age . Two doses of a live PM-1 P . multocida vaccine protected broiler breeder hens against virulent challenge up to 32 wk of age when measured antibody levels had a range of 1951-4346 and a geometric titer of 3000.

Avian Dis, 1998 Jan-Mar, 42(1), 186 - 9
Serum and egg yolk IgG antibody titers from laying chickens vaccinated with Pasteurella multocida; Ling YS et al.; Through determining the serum and egg yolk antibody titers in immunized laying hens to Pasteurella multocida regularly, the growth-decline trend of the egg yolk antibody levels was found to be similar to that of the serum antibody levels (r = 0.94), but the growth and decline of the egg yolk antibody seemed to be delayed 3-6 days compared with that of the serum antibody, and the egg yolk antibody titers were generally lower than those of the serum antibody (P < 0.01) . Serum and egg yolk antibody levels declined 3 and 6 days, respectively, after booster immunizations . The higher the antibody levels were before booster immunization, the more they declined.

J Vet Diagn Invest, 1998 Jan, 10(1), 49 - 55
Biovariants of isolates of Pasteurella from domestic and wild ruminants; Jaworski MD et al.; A total of 608 bacterial isolates previously identified as Pasteurella haemolytica biotypes A and 3, P . trehalosi, and P . multocida, were separated into 73 distinct biovariants using 21 phenotypic characteristics . The largest group (54%) of wildlife isolates was identified as biogroup 2 and biogroup 2 variants . Biogroup 2 and biogroup 2 variants accounted for only 17% of isolates from domestic ruminants and were all from sheep . In contrast, 43% of isolates from domestic ruminants were identified as biogroup 1 and biogroup 1 variants, whereas only 6% of isolates from wildlife were identified in these groups . The majority of biogroup 1 isolates from wild ruminants were from 1 group of bighorn sheep in Arizona that were geographically separated from other wildlife sampled . Similarly, 1 biogroup 2 variant, 2E, was cultured only from free-ranging Dall sheep in Alaska . Twelve percent of domestic isolates and 6% of wildlife isolates were indole positive . The remaining isolates from wildlife (33%) and domestic animals (30%) were distributed among 53 distinct biovariants . None of these individual biovariants represented >4% of the total isolates . Phenotypic characterization was valuable for distinguishing between isolates from different hosts and from different geographic areas and can be used to assist in epidemiologic studies.

J Vet Med Sci, 1998 Feb, 60(2), 181 - 7
The presence of two low molecular mass proteins immunologically related to 14 kilodalton serum amyloid A in the lipoprotein fraction and their decreased serum concentrations in calves with experimentally induced pneumonia; Yamamoto M et al.; A 14 kilodalton (kDa) serum amyloid A (apoSAA) protein was purified from cow serum . Rabbit antiserum to the 14 kDa apoSAA recognized, in addition to the 14 kDa protein, a 7.5-9.0 kDa protein and a protein having a molecular mass of less than 6.5 kDa (< 6.5 kDa protein) . The possibility that the two proteins were contaminants was excluded by results showing that the two proteins detected in early stages of purification procedures were not found in the purified 14 kDa apoSAA fraction, as revealed by immunoblot analysis . As in the 14 kDa apoSAA, the 7.5-9.0 kDa protein was localized in the high-density lipoprotein fraction, while the < 6.5 kDa protein was in the low-density lipoprotein fraction . In calves with pneumonia induced by inoculation to the lungs of Pasteurella haemolitica, the serum concentration of the 14 kDa apoSAA was increased, whereas those of the 7.5-9.0 kDa and the < 6.5 kDa proteins were conversely decreased . The time-course study indicated that the increase in concentration of the 14 kDa apoSAA and decrease in that of the < 6.5 kDa protein occurred almost simultaneously . These results suggest that the 14 kDa apoSAA and the immunologically related 7.5-9.0 kDa and < 6.5 kDa proteins act as positive and negative acute phase reactants, respectively, and also that concentrations of the three proteins are regulated in concert in acute phase plasma.

Toxicol Sci, 1998 Jan, 41(1), 129 - 37
Uranyl nitrate: 91-day toxicity studies in the New Zealand white rabbit; Gilman AP et al.; These studies were undertaken to derive a lowest-observed-adverse-effect level (LOAEL) in the New Zealand White rabbit following a 91-day exposure to uranium (U, as uranyl nitrate hexahydrate, UN) in drinking water . Males were exposed for 91 days to UN in their drinking water (0.96, 4.8, 24, 120, or 600 mg UN/L) . Subsequently, females were similarly exposed for 91 days (4.8, 24, or 600 mg UN/L) . Control groups were given tap water (< 0.001 mg U/L) . Regular observations were recorded, and urine was collected periodically . Four males showed evidence of Pasteurella multocida infection and were excluded from the study . Following the study, all animals were euthanized, and multiple hematological and biochemical parameters were determined . Necropsies were conducted, and histopathological examination was performed . The hematological and biochemical parameters were not affected in a significant exposure-related manner . Dose-dependent differences consisted of histopathological changes limited primarily to kidney . Changes in renal tubules were characteristic of uranium toxicity . Based on changes in the tubular nuclei, the 91-day LOAEL for males in this study is 0.96 mg UN/L drinking water . The females drank 65% more water than the males, yet appeared to be less affected by the exposure regimen, although they also developed significant tubular nuclear changes in their lowest exposure group, deriving a LOAEL of 4.8 mg UN/L . Tissue uranium residue studies suggested that pharmacokinetic parameters for the males and females differ, possibly accounting for the difference in observed sensitivity to UN . An adverse effect of P . multocida infection cannot be excluded.

Microb Pathog, 1998 Jan, 24(1), 37 - 46
Construction of an isogenic leukotoxin deletion mutant of Pasteurella haemolytica serotype 1: characterization and virulence; Tatum FM et al.; Allelic replacement was used to generate two isogenic lktA deletion mutants of Pasteurella haemolytica serotype 1 that were incapable of synthesizing leukotoxin (Lkt) . Southern blot data confirmed that lktA sequences were absent in the two P . haemolytica deletion mutants . Culture supernatants and whole cell lysates from the wild type P . haemolytica, D153 parent strain, but not the lktA deletion mutants, contained immunoreactive and bioactive leukotoxic protein . In addition, only the parent strain was haemolytic when grown on bovine and sheep blood agar plates . Virulence of the lktA deletion mutant, lktA 77, was compared with the parent in an experimentally infected calf model of pneumonic pasteurellosis . Results revealed significant reduction in virulence in the lktA mutant as measured by clinical and lung lesion scores . Notable differences in histological changes such as markedly reduced necrosis and lack of leukocyte degeneration occurred in calves infected with the lktA mutant in comparison with those infected with the parent wild-type strain . Thus, it appears that leukotoxin plays a important role in the pathogenesis of lung injury in bovine pneumonic pasteurellosis .

Microb Pathog, 1997 Dec, 23(6), 371 - 80
Identification of major antigenic proteins of Pasteurella piscicida; Hirono I et al.; Two different antigenic protein-coding clones (PPA1 and PPA2) were isolated using anti-Pasteurella piscicida rabbit serum from a genomic DNA library of P . piscicida strain KP9038 . The PPA1 and PPA2 expressed 7 kDa and 45 kDa proteins in Escherichia coli, respectively, and the molecular sizes of these expressed proteins are the same as these of the major antigenic proteins of P . piscicida . PPA1 encodes a protein of 83 amino acids residues, which is similar to the bacterial lipoprotein . Comparison of the predicted amino acid sequence of the PPA1-encoded 7 kDa protein of P . piscicida with previously reported bacterial lipoprotein sequence data revealed that it shares about 40% amino acid sequence identity . PPA2 has two large open reading frame (ORFs) . The larger ORF (encoding 452 amino acid residues) encodes a homolog of DegQ protease, and the smaller ORF (371 amino acid residues) encodes a homolog of DegS protease . The antibodies reacted with the larger ORF-encoded 45 kDa DegQ homolog protein . The DegQ and DegS homolog proteins contain an export signal and a serine protease active site . The structural features of the PPA2-coding locus are similar to those of the loci in E . coli for the degQ and degS serine protease genes . A sequence in the 3' non-coding region of Vibrio hollisae thermostable hemolysin gene that is highly homologous with a similar located sequence in the Pseudomonas putida p-cresol methylhydroxylase gene is also found in the 3' non-coding region of the degS homolog gene of the PPA2 .

FEMS Immunol Med Microbiol, 1998 Jan, 20(1), 29 - 36
Effect of Pasteurella haemolytica outer membrane proteins on bovine neutrophils; Iovane G et al.; The major outer membrane proteins (OMPs) isolated from Pasteurella haemolytica induce alterations of the biological activity of bovine polymorphonuclear leukocytes (PMNs) . A dose-dependent reduction of the capacity of adherence to nylon wool in vitro was observed . OMPs also acted as chemotaxins at concentrations between 5 and 20 microg/ml . Concentrations lower than 5 microg/ml did not give considerable results . Preincubation with 5 microg/ml of OMPs led to modifications in the values of the phagocytic index and of intracellular killing, which were found to be diminished with respect to controls.

FEMS Microbiol Lett, 1997 Nov 15, 156(2), 223 - 6
Identification of restriction barriers in Pasteurella multocida; Hoskins IC et al.; Several naturally occurring antibiotic resistance plasmids were isolated from Pasteurella multocida type D strains . One plasmid, pPM1, was used to study transfer of DNA among P . multocida strains, and could be transferred into Escherichia coli and some P . multocida isolates . However, pPM1 could only be transferred into the toxigenic P . multocida LFB3 at very low frequency . Plasmid recovered from the electrotransformants could be transferred to LFB3 at high frequency . These plasmid DNAs were resistant to PstI, and sensitive to DpnI digestion . Sensitivity to DpnI was common to all the P . multocida DNAs, but resistance to PstI was confined to LFB3 . Plasmid pPM1 treated with PstI methylase was able to transform LFB3 at an increased frequency compared to unmethylated DNA, suggesting that LFB3 has a restriction system which cleaves at or near PstI sites.

Rev Sci Tech, 1997 Aug, 16(2), 599 - 604
Public health risks of ostrich and crocodile meat; Huchzermeyer FW; This paper discusses the infectious agents and chemical substances potentially capable of contaminating the meat of ostriches and crocodiles and which thus pose a danger to human handlers and consumers . For ostrich meat, there is no danger from Crimean-Congo haemorrhagic fever or spongiform encephalopathy . Contamination of ostrich meat with salmonellae, chlamydia, pasteurellae, mycobacteria and erysipelas might be possible, but has never been reported . No parasites are known which could be transmitted through ostrich meat to human consumers . Residues from growth hormones, antibiotics and acaricides are potential public health hazards . For crocodile meat, there is a distinct possibility of contamination with salmonellae, depending on housing, feed, slaughter technique and hygiene practices under which the animal is reared . Chlamydial infections are common on some crocodile farms in southern Africa . Mycobacteriosis is extremely rare . Tapeworm cysts have been found in crocodile meat in two cases only . Trichinellosis has been reported on several crocodile farms in Zimbabwe . A generalised coccidiosis with invasion of organs and tissues has been seen in several species of crocodiles, but should present no danger to consumers.

Eur Respir J, 1997 Dec, 10(12), 2904 - 6
Pancoast's syndrome due to chronic pneumonia by Pasteurella multocida; Ribas J et al.; Infectious causes of Pancoast's syndrome are extremely rare . We describe the case of a patient with Pancoast's syndrome due to chronic pneumonia resulting from Pasteurella multocida . The patient was not immunosuppressed and had had no contact with animals . The diagnosis was made by transthoracic needle aspiration and institution of therapy with cefuroxime-axetil resulted in resolution of his symptoms.

Microbiology, 1998 Feb, 144 ( Pt 2), 279 - 89
Population structure and diversity of avian isolates of Pasteurella multocida from Australia; Blackall PJ et al.; A total of 110 isolates of Pasteurella multocida from Australian poultry and reference strains for the 16 somatic serovars plus the three subspecies (gallicida, multocida, septica) were analysed to examine their population structure and diversity . The 81 field isolates examined by multilocus enzyme electrophoresis (MLEE) were diverse, being divided into 56 electrophoretic types (ETs), with the 19 reference strains in another 15 ETs . The population was clonal and somatic serotyping was not particularly useful in establishing relationships between isolates . The 71 ETs formed three distinct subclusters (A, B and C) at a genetic distance of 0.36 . Biovars tended to be associated with these subclusters: A with biovars 1, 3, 4, 5 and 8 and B with biovars 2, 6, 7, 9 and 10 . Ribotyping, performed on all 110 isolates using Hpall, recognized 21 ribotypes forming nine clusters (R1-R9) . The isolates in ribotype cluster R1 were almost identical to those in MLEE cluster B . Using both MLEE and ribotyping, the 19 non-Australian reference strains were found to be distributed over the full diversity of the Australian isolates of P . multocida . This study has shown that a range of P . multocida clones are associated with fowl cholera in Australia and that many of the Australian isolates are similar to non-Australian reference strains . Both the MLEE results and the ribotyping data identified a previously unrecognized subset of P . multocida strains.

Arch Pediatr, 1997 Nov, 4(11), 1116 - 8
{Maternal and neonatal Pasteurella multocida infection}; Escande F et al.; BACKGROUND: Materno-fetal infection due to Pasteurella multocida is rare; it may be severe in the neonate . CASE REPORT: A 27-year old woman was admitted at 37 weeks' gestation with a history of abdominal cramps . Twenty-four hours after delivery, the mother was febrile (40 degrees C) and was given intravenous cefotaxime (2 days), followed by cefpodoxime (15 days) . The newborn was febrile and hypotonic 24 hours after birth; he received an infusion of hydroxyethylamidon and was given cefotaxime (3 days), netilmicin (6 days) and amoxicillin (10 days) . Pasteurella multocida was isolated from placenta, blood and gastric fluid in the baby and in blood cultures and vaginal swab in the mother . It was established that the mother was bitten by her dog during the pregnancy and wounded a few days before delivery . CONCLUSION: This neonate was infected during the delivery and the source of mother's contamination was easy to determinate: pet animals were kept by the family and there was an history of wounds during her pregnancy.

Eur J Obstet Gynecol Reprod Biol, 1998 Jan, 76(1), 71 - 3
Sepsis puerperalis caused by a genotypically proven cat-derived Pasteurella multocida strain; Voss A et al.; We report a disseminated intrauterine Pasteurella multocida infection in a puerperal woman who could not remember any traumatic exposure to her cat . An oral swab taken from the cat, just 2 days after the patient's admission, grew Pasteurella multocida, with an PCR-fingerprinting pattern identical to the patient's isolate . Hand-washing after every contact with cats and dogs and if feasible separation of in-house pets from mother and infant should be applied to prevent this uncommon but serious occurrence of post-partum infections . To our knowledge this is the first case of Pasteurella multocida 'child-bed fever', with a genotypically identical strain isolated from the in-house cat.

Acta Orthop Belg, 1997 Dec, 63(4), 310 - 2
Late infection after total knee arthroplasty caused by Pasteurella multocida; Antuna SA et al.; The authors report a case of Pasteurella multocida infection in a total knee arthroplasty as a result of a dog bite . The patient was treated with one-stage reimplantation of a new prosthesis and with intravenous antibiotics, resulting in complete relief of symptoms with no evidence of recurrence of infection after 24 months.

J Wildl Dis, 1998 Jan, 34(1), 137 - 44
Serologic and parasitologic survey of the endangered Attwater's prairie chicken; Peterson MJ et al.; Because conservation biologists have postulated that infectious diseases may have potentiated the endangerment of the Attwater's prairie chicken (Tympanuchus cupido attwateri), free-living prairie chickens were surveyed from all remaining populations for helminthic endoparasites and antibody against the etiological agents of nine infectious diseases . Samples from 4 of 27 adult males were positive for anti-Pasteurella multocida antibody . All other serologic tests were negative (n = 19) . We identified Dispharynx nasuta, a parasite previously associated with disease in other grouse from North America, in one of three adult Attwater's prairie chickens examined . Evidence of Trichostrongylus cramae was found for eight of nine suitable samples, which represents the first report of this parasite in prairie grouse . The mean intensity of T . cramae in Attwater's prairie chicken was 1,019.3 (Range = 3-1,906; n = 3) . Further work is needed to determine whether P . multocida, T . cramae, or D . nasuta are detrimental to Attwater's prairie chicken populations . If so, conservation biologists could reduce the prevalence and incidence of these parasites and potentially gain more time to address the habitat conditions thought to be the ultimate cause of population declines.

J Wildl Dis, 1998 Jan, 34(1), 182 - 5
A cryopreservation method for Pasteurella multocida from wetland samples; Moore MK et al.; A cryopreservation method and improved isolation techniques for detection of Pasteurella multocida from wetland samples were developed . Wetland water samples were collected in the field, diluted in dimethyl sulfoxide (DMSO, final concentration 10%), and frozen at -180 C in a liquid nitrogen vapor shipper . Frozen samples were transported to the laboratory where they were subsequently thawed and processed in Pasteurella multocida selective broth (PMSB) to isolate P . multocida . This method allowed for consistent isolation of 2 to 18 organisms/ml from water seeded with known concentrations of P . multocida . The method compared favorably with the standard mouse inoculation method and allowed for preservation of the samples until they could be processed in the laboratory.

Neoplasma, 1997, 44(4), 205 - 11
The leukocyte common antigen (CD45) on human pre-B leukemia cells: variant glycoprotein form expression during the cell exposure to phorbol ester is blocked by a nonselective protein kinase inhibitor H7; Duraj J et al.; The human pre-B acute lymphoblastic leukemia cell line REH6 was utilized for characterization of CD45 glycoprotein by monoclonal antibodies (mAb) recognizing four distinct CD45 antigen specificities, i.e . nonrestricted CD45, restricted CD45RA, CD45RB and CD45R0 . Immunoprecipitation revealed two antigen specificities on REH6 cells of m.w . 220 kDa and 190 kDa, both presenting wide range of isoelectric point pI approximately 6.0-7.5 . Nonrestricted CD45 epitopes were not affected by the sialyl acid cleavage with sodium metaperiodate or neuraminidase, but were sensitive to both, tunicamycin, the N-glycosylation inhibitor and monensin, an inhibitor of protein transport through the Golgi compartment . O-sialoglycoprotein endopeptidase from Pasteurella haemolytica A1 partially cleaved CD45RA and CD45RB epitopes, while nonrestricted CD45 determinants were not affected by this enzyme . Limited proteolysis of this antigen resulted in the appearance of 160-180 kDa peptide domains which retained CD45 epitopes . Further, the treatment of cells with phorbol myristate acetate (PMA) induced marked down-regulation of 220 and 190 kDa isoforms and the appearance of new 210, 180 and 170 kDa variant glycoprotein forms which were not found on parental cells . This PMA effect was not accompanied by the programmed cell death and was markedly blocked by a nonselective protein kinase (PK) inhibitor isoquinoline sulfonamide H7 . Modulation of CD45 by phorbol esters might serve as an in vitro model for an additional insight into the function of CD45 in hematopoietic cells.

Onderstepoort J Vet Res, 1997 Sep, 64(3), 205 - 12
The humoral immune response in cattle after immunization with a multivalent IBR/PI3/Pasteurella haemolytica A1 leukotoxin vaccine; Odendaal MW et al.; A multivalent vaccine consisting of inactivated bovine herpes virus-1 (BHV-1), also known as infectious bovine rhinotracheitis virus (IBR), para-influenza type-3 virus (PI3) and the leukotoxin of Pasteurella haemolytica A1, were combined with the addition of aluminium hydroxide as adjuvant, and administered to post-weaned calves, and the serum tested for seroconversion to each antigen . Two groups of calves (n = 150 and n = 68) were used and were randomly divided into three subgroups . The first group of 150 calves were immunized with the multivalent vaccine (three batches) to test its first-stage stability (vaccine 3 months old) and the second group were immunized with the same vaccine 1 year later, in order to test its immunogenicity . A significant increase in titres occurred after the day 0 and 28 immunizations, for each of the three antigens in the multivalent vaccine, as measured on days 0 and 42 . Immunoconversion occurred after immunization with the 3-month- and 1-year-old vaccine . The immunogenic stability of antigens in the vaccine was demonstrated after a 1-year period when the vaccine was kept at 4-6 degrees C.

Avian Dis, 1997 Oct-Dec, 41(4), 972 - 6
Lack of protection against avian cholera by vaccination with recombinant P6-like protein from Pasteurella multocida; Kasten RW et al.; The gene encoding the P6-like protein of Pasteurella multocida was cloned in the baculovirus expression system . Baculovirus-expressed recombinant protein was used to parenterally immunize 6-wk-old Nicholas broad-breasted white turkeys . Turkeys developed significant antibody titers to the recombinant protein as measured by enzyme-linked immunosorbent assay . Two weeks after the last immunizing injection, vaccinated turkeys were placed in contact with turkeys infected with P . multocida strain P1059, as were nonvaccinated control birds . No differences occurred in percent mortality between the two groups . We conclude that parenterally administered recombinant P6-like protein does not protect turkeys from avian cholera.

Vet Microbiol, 1997 Oct 16, 57(4), 383 - 95
Analysis of haemorrhagic septicaemia-causing isolates of Pasteurella multocida by ribotyping and field alternation gel electrophoresis (FAGE); Townsend KM et al.; Ribotyping and field alternation gel electrophoresis (FAGE) were used to examine 19 Pasteurella multocida isolates, and to assess the ability of these techniques to differentiate P . multocida strains that cause haemorrhagic septicaemia (HS) . Reproducible patterns were obtained from both methods, with FAGE demonstrating greater discriminatory power than ribotyping . FAGE analysis was particularly useful in distinguishing North American cultures originating from the 1922 Yellowstone National Park Buffalo 'B' strain, demonstrating the ability to detect genetic alterations induced by repeated subculture . A remarkable homogeneity was observed among Asian HS strains following ribotyping and FAGE analysis, with a clear distinction observed between virulent and avirulent HS isolates . This study has illustrated the value of genomic fingerprinting methods in distinguishing strains of similar serotype, and the capability of these methods to produce detailed characterisation of P . multocida isolates.

Vet Microbiol, 1997 Oct 16, 57(4), 355 - 60
Phenotypic characterisation of Pasteurella multocida isolates from Australian pigs; Blackall PJ et al.; A phenotypic characterisation of 150 isolates of bacteria previously identified as Pasteurella multocida was performed . All the isolates had been obtained from Australian pigs in the three eastern States of Queensland (110 isolates), New South Wales (21 isolates) and Victoria (19 isolates) . Seven different biochemical biovars were recognised amongst the isolates . A total of 100 isolates (67%) were assigned to biovar 3, previously shown to be the most common biovar in isolates of P . multocida from Australian poultry {Fegan, N., Blackall, P.J., Pahoff, J.L., 1995 . Phenotypic characterisation of Pasteurella multocida isolates from Australian poultry . Vet . Microbiol., 47, 281-286.} . Six of the seven biovars, including biovar 3, were identified as P . multocida subsp . multocida, 124 isolates in total . One other biovar, consisting of thirteen isolates, was identified as P . multocida subsp . gallicida . Within the six biovars that were identified as P . multocida subsp . multocida, biovars 12, 13 and 14 represented unusual biochemical variants . The nine isolates assigned to biovar 12 appeared to be lactose positive variants of P . multocida subsp . multocida . The three isolates in biovar 13 appeared to be ornithine decarboxylase (ODC) negative variants of P . multocida subsp . multocida . The single isolate in biovar 14 appeared to be an ODC negative, lactose positive variant of P . multocida subsp . multocida.

Can J Vet Res, 1998 Jan, 62(1), 1 - 8
Alterations in bovine platelet function and acute phase proteins induced by Pasteurella haemolytica A1; Cheryk LA et al.; Platelet function was assessed by aggregometry in 10 Holstein calves before and after exposure to Pasteurella haemolytica (biotype A, serotype 1) by intrabronchial challenge . At 24 h after exposure the platelets had become more reactive to stimulation with known platelet agonists such as adenosine diphosphate (ADP) and platelet-activating factor (PAF) and the platelet aggregates that formed were more resistant to disaggregation . The activation of platelets was an early response in the challenged calves as platelet function had returned to pretreatment levels 72 h after exposure to the bacteria while the acute phase reactant proteins, haptoglobin and fibrinogen, were approaching their peak values and alpha 2-macroglobulin levels had also risen significantly (P < 0.05) at this time . The plasma levels of these proteins were still elevated and albumin levels were depressed 6 d post-treatment . At post-mortem all calves exhibited pneumonic tissue damage . When P . haemolytica leukotoxin was added directly to bovine platelet suspensions both spontaneous aggregation and an increase in the aggregation response to ADP and PAF stimulation were observed . The morphological appearance of the platelet aggregates exhibited the typical pattern for bovine platelets with 2 distinct zones of cells being visible within each aggregate . One zone contained platelets in which the cytoplasmic granules were still evident and the other zone contained irregularly shaped platelets devoid of granular content . In the latter zone, discrete gaps, or pores, were evident in the plasma membrane of numerous platelets . This pore formation is characteristic of leukotoxin action and is not observed in ADP or PAF induced aggregates.

Vet Immunol Immunopathol, 1997 Sep 19, 58(3-4), 277 - 86
Early changes in the phenotypic composition of lymphocytes in the bronchoalveolar lavage of pigs after aerogenic immunization with Pasteurella multocida aerosols; Kohler H et al.; The phenotypic composition of bronchoalveolar lymphocytes (BALL) of healthy untreated pigs and of pigs immunized via aerosol with a live Pasteurella multocida mutant was measured cytofluorometrically in comparison to blood lymphocytes (PBL) . Cells were analyzed using monoclonal antibodies against porcine IgM, IgA, IgG and SWC3 in single-colour fluorescence and the following antibody combinations for two-colour fluorescence: CD2/SWC1, SWC1/CD25 and CD4/CD8 . In nonimmunized pigs, differences between lymphocyte subsets derived from blood and lung were obvious . The numbers of CD2-SWC1+ T-cells, CD25+ activated lymphocytes and IgG+ cells were significantly higher in the bronchoalveolar compartment . Aerosol immunization with P . multocida caused only insignificant changes in the phenotypic composition of PBL whereas the composition of lung-derived lymphocytes changed markedly . The percentage of CD2-SWC1+ lymphocytes and of CD25+ cells coexpressing the SWC1 antigen in BALL increased up to 10 days after aerosol administration, whereas the percentage of all Ig+ cells decreased . These data reflect an early cellular reaction to an aerogenic immunization with a P . multocida aerosol, characterized by an increase in CD2+ T-cells and a T-cell activation.

Res Vet Sci, 1997 Sep-Oct, 63(2), 151 - 5
REP-PCR analysis of Pasteurella multocida isolates that cause haemorrhagic septicaemia; Townsend KM et al.; Amplification of multiple P multocida genomic DNA fragments by outwardly-directed primers based on the repetitive extragenic palindromic (REP) consensus sequence, generated complex profiles in a PCR-based fingerprinting method known as REP-PCR . Polymorphisms within REP-PCR profiles were used to characterise 38 isolates of P multocida . The high degree of homogeneity observed among haemorrhagic septicaemia (HS) strains of serotype B and E provided evidence of a disease-associated REP profile that may serve as a novel method for the identification of HS strains regardless of serotype . REP-PCR profiles of other P multocida serotypes were highly variable, illustrating the potential of this technique for the molecular fingerprinting of fowl cholera or atrophic rhinitis isolates . A specific amplified REP fragment was isolated and used to probe membrane-bound digested P multocida genomic DNA . Hybridisation patterns not only distinguished HS-causing isolates from non-HS P multocida, but also demonstrated a degree of relatedness between HS and HS-like strains.

Rev Esp Enferm Dig, 1997 Oct, 89(10), 786 - 9
{Spontaneous peritonitis in a cirrhotic patient with a cat: Pasteurella multocida infection of the ascitic fluid}; Bilbao Garay J et al.; Spontaneous peritonitis due to Pasteurella multocida is exceptional . As far as we know only 11 other cases have been reported . We describe a 45 year old patient who presented with a spontaneous Pasteurella multocida peritonitis as the first complication of a previously undiagnosed cirrhosis . The patient used to play with his pet cat, not recalling having ever sustained any injury . Cultures of the cat's mouth grew the same strain of Pasteurella multocida than was found in the patient's ascitic fluid . The clinical findings of the previous cases, most of which were also related to non traumatic exposure to domestic animals, are here described . Pasteurella multocida in one potential agent in the cirrhotic patient presenting with spontaneous peritonitis, especially if in close contact with animals, cats being the most often carriers.

Appl Environ Microbiol, 1997 Dec, 63(12), 4986 - 9
Vibrio sp . strain NM 10, isolated from the intestine of a Japanese coastal fish, has an inhibitory effect against Pasteurella piscicida; Sugita H et al.; Vibrio sp . strain NM 10 with an inhibitory activity against Pasteurella piscicida K-III was isolated from the intestine of a spotnape ponyfish (Leiognathus nuchalis) . This bacterium efficiently produced an antibacterial substance after growth at 20 degrees C for 24 h on 1/5 PYBG agar prepared with 50% seawater at pHs of 7.5 to 9.0 . The antibacterial substance was heat labile and proteinaceous, with a molecular mass of less than 5 kDa, possibly a bacteriocin or a bacteriocin-like substance.

Mol Biotechnol, 1997 Oct, 8(2), 189 - 91
The sacB gene cannot be used as a counter-selectable marker in Pasteurella multocida; Jost BH et al.; The use of the Bacillus subtilis sacB gene as a counter-selectable marker was assessed in serogroup A and B strains of Pasteurella multocida . Expression ofsacB failed to render any of the strains sensitive to sucrose, indicating that the sacB gene can not be used as a positive selection system in P . multocida.

J Bacteriol, 1997 Dec, 179(24), 7856 - 64
Cloning and characterization of the major outer membrane protein gene (ompH) of Pasteurella multocida X-73; Luo Y et al.; The major outer membrane protein (OmpH) of Pasteurella multocida X-73 was purified by selective extraction with detergents, followed by size exclusion chromatography . The planar lipid bilayer assay showed that OmpH has pore-forming function . The average single channel conductance in 1.0 M KCl was 0.62 nS . The gene (ompH) encoding OmpH has been isolated and sequenced by construction of a genomic library and PCR techniques . The coding region of this gene is 1,059 bp long . The predicted primary protein is composed of 353 amino acids, with a 20-amino-acid signal peptide . The mature protein is composed of 333 amino acids with a molecular mass of 36.665 kDa . The ompH gene encoding mature protein has been expressed in Escherichia coli by using a regulatable expression system . The ompH gene was distributed among 15 P . multocida serotypes and strain CU . Protection studies showed that OmpH was able to induce homologous protection in chickens . These findings demonstrate that OmpH is a protective outer membrane porin of strain X-73 and is conserved among P . multocida somatic serotypes.

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