Pasteurella

J Wildl Dis, 1997 Oct, 33(4), 738 - 48
Evaluation of a multivalent Pasteurella haemolytica vaccine in bighorn sheep: safety and serologic responses; Miller MW et al.; We examined effects of a multivalent Pasteurella haemolytica vaccine (serotypes A1, A2, T10) on humoral immune responses and P . haemolytica isolation rates in bighorn sheep (Ovis canadensis) . Thirty captive bighorns, divided into groups of three on the basis of age, sex, and previous history of pneumonic pasteurellosis, received 0, 1, or 2 vaccine doses . Mild, transient lameness in most bighorns 1 day after initial vaccination was the only adverse effect observed . Oropharyngeal (> or = 75%) and nasal (< or = 50%) isolation rates for P . haemolytica did not differ among treatment groups . Ten of 36 distinguishable biogroup variants accounted for about 87% of the 464 P . haemolytica isolates from bighorns, but prevalences of specific biogroups were not affected by vaccination . Bighorns receiving 1 or 2 vaccine doses showed marked elevations in leukotoxin neutralizing antibody titers beginning 1 wk after vaccination . Agglutinating antibody titers to serotype A1 and A2 surface antigens were also elevated in vaccinated bighorns within 2 wk after vaccination; agglutinating antibody titers to serotype T10 surface antigens were relatively high in all three groups but appeared unaffected by vaccination . Vaccination 7 to 14 wk prior to parturition elevated leukotoxin neutralizing antibody titers in colostrum, but neither leukotoxin neutralizing nor serotype A1 surface antigen agglutinating antibody titers differed through 16 wk of age among lambs born to dams from different vaccine dose groups . Our data demonstrate that this multivalent P . haemolytica vaccine is safe and stimulates marked antibody responses in bighorn sheep . Further evaluation of this vaccine as a tool in preventing and managing pasteurellosis in bighorn sheep appears warranted.

Vet Clin North Am Food Anim Pract, 1997 Nov, 13(3), 471 - 81
Bovine respiratory tract disease caused by bovine viral diarrhea virus; Potgieter LN; Although several viruses and bacteria are capable of inducing bovine respiratory tract disease, a pivotal organism in the cause of this complex disease may be bovine viral diarrhea virus (BVDV) . Circumstantial evidence has long supported this hypothesis . It is frequently present in diseased respiratory tract tissues often together with other viruses or bacteria . Field observations suggest marked synergism occurs . Researchers have confirmed that, in most instances, the virus itself elicits only a mild respiratory tract disease in susceptible calves, but some strains may be much more pneumo-pathogenic than others . Experimental evidence now supports the hypothesis, that BVDV markedly enhances respiratory tract disease caused by IBRV, BRSV, or Pasteurella haemolytica; that it impairs pulmonary immunity; and that it, by itself, may produce mild respiratory tract disease.

Zentralbl Bakteriol, 1997 Oct, 286(3), 333 - 54
Genotypic relationships among strains classified under the (Pasteurella) haemolytica-complex as indicated by ribotyping and multilocus enzyme electrophoresis; Angen O et al.; Two-hundred and one strains classified under the (Pasteurella) haemolytica-complex isolated from cattle, sheep, deer, pigs, hares and rabbits were investigated by ribotyping . Fifty-nine of these strains were selected for further studies using multilocus enzyme electrophoresis (MEE) . A correlation between the clusters identified by ribotyping and MEE was demonstrated and the results furthermore indicated that a genetic basis exists for most clusters previously outlined by the use of quantitative evaluation of phenotypic data . The taxonomic relevance of ornithine decarboxylase and fermentation of L-arabinose, D-sorbitol and glucosides for taxonomic delineation within the (P.) haemolytica-complex was supported . A taxonomic importance was further indicated for ONPG, ONPX, ONPF, meso-inositol, D-xylose, maltose, dextrine and NPG in relation to some of the taxa . Within the porcine taxon 15, however, differences in ornithine decarboxylase did not correspond to genetic clusters . Six lineages were revealed by MEE . Lineage A contained electrophoretic types (ETs) representing biogroups 1, 3A-3H, 8A and 9, indicating a genetic relationship between these groups--an observation which was supported by ribotyping . Lineage B included biogroup 8D, 3 strains from biogroup 10 and a single strain from biogroup 1 and taxon 18/biovar 1 . Lineage C contained strains allocated to biogroup 6 from ruminants and the porcine taxon 15 . The similarity between these two groups was accentuated by ribotyping . Lineage D and the single isolate in lineage E contained strains allocated to biogroups 7, 10, 8B and 8C, in addition to single strains from biogroups 6 and 9 . The same strains were found in the heterogenous ribotype cluster 17 . Lineage F contained strains representing the leprine taxon 20 and the ruminant (P.) granulomatis . Ribotyping indicated that the ruminant biogroup 3J was affiliated with both taxon 20 and (P.) granulomatis.

Zentralbl Bakteriol, 1997 Oct, 286(3), 317 - 32
Further studies of the relationships among strains classified as taxon 15, taxon 18, taxon 20, (Pasteurella) granulomatis or the (Pasteurella) haemolytica-complex in ruminants using quantitative evaluation of phenotypic data; Angen O et al.; Ninety-three trehalose-negative (P.) haemolytica-like strains of ruminant, porcine and leprine origin were investigated . A quantitative evaluation of phenotypic tests was used and the results obtained were compared with those from 246 previously investigated ruminant strains . Cluster analysis of the results obtained displayed most of the taxa as distinct groups which could be related to differences in key characters . Although only minor phenotypic differences were observed between the taxa investigated and the taxa were internally heterogeneous for many of the tests, it was possible to identify characters separating most groups . However, in three instances, taxa isolated from different species could not be separated by any of the tests used or by quantitative evaluation of all 79 tests--the only difference being the species of animals from which they had been isolated . Taxa which could not be separated by phenotypic tests included the ruminant biogroup 6 of (P.) haemolytica and the porcine taxon 15/biovar 1, the ruminant biogroup 7 of (P.) haemolytica and the porcine taxon 15/biovar 2, and ruminant biogroup 31 of (P.) haemolytica and the leprine taxon 20/biovar 1.

Am J Vet Res, 1997 Nov, 58(11), 1227 - 31
Effects of Pasteurella haemolytica leukotoxin and lipopolysaccharide on histamine, prostanoid, and leukotriene release by bovine lung parenchyma in vitro; Saban R et al.; OBJECTIVE: To identify the effect of Pasteurella haemolytica lipopolysaccharide (LPS) and leukotoxin (LKT) on spontaneous and calcium ionophore-induced histamine and inflammatory mediator release from isolated bovine lung parenchyma . SAMPLE POPULATION: Lungs from 8 healthy cattle . PROCEDURE: Isolated bovine lung parenchyma was incubated in vitro for 2 hours with LKT or LPS, and spontaneous and induced release of inflammatory mediators was determined . RESULTS: LKT and LPS increased spontaneous release of histamine and leukotriene B4 . In addition, incubation with LPS increased spontaneous release of prostaglandin E2 . Moreover, a differential effect of the 2 toxins on calcium ionophore-induced inflammatory mediator release was observed . LKT specifically primed isolated lung parenchyma to release leukotriene B4 and thromboxane B2 in response to calcium ionophore, whereas LPS did not alter the profile of prostanoids released by bovine lung tissue exposed to calcium ionophore . CONCLUSIONS: Pasteurella haemolytica toxins have a direct effect on bovine lung parenchyma, causing release of inflammatory mediators, which contribute to response to infection . Furthermore, bacterial toxins (LKT in this study) may sensitize tissues to the effects of other irritant stimuli, amplifying the inflammatory response.

J Wildl Dis, 1996 Oct, 32(4), 594 - 602
Experimental contact of bighorn sheep (Ovis canadensis) with horses and cattle, and comparison of neutrophil sensitivity to Pasteurella haemolytica cytotoxins; Foreyt WJ et al.; Peripheral blood neutrophils from horses, cattle, and Rocky Mountain bighorn sheep (Ovis canadensis canadensis) were evaluated for susceptibility to cytotoxin-dependent lysis of different biotypes and serotypes of Pasteurella haemolytica of domestic sheep, cattle, bighorn sheep, or mountain goat (Oreamnos americana) origin utilizing a cytotoxicity assay which measures the degree of bacteria cytotoxin-killing of neutrophils . All isolates of P . haemolytica (biotypes A and T) were noncytotoxic to horse neutrophils . Thirteen of 18 R haemolytica biotype A isolates were cytotoxic (> 50% neutrophil death in vitro) to bighorn sheep neutrophils, and four of 10 P . haemolytica biotype A isolates were cytotoxic to neutrophils of cattle; P . haemolytica biotype T (= Pasteurella trehelosi) isolates were noncytotoxic to neutrophils of bighorn sheep and cattle . When six bighorn sheep were pastured with three horses, only P . haemolytica biotype T isolates were recovered from the bighorn sheep throughout the study; Pasteurella spp . organisms were not isolated from the three horses . At initiation of a study where five bighorn sheep were pastured with three cattle, P . haemolytica biotype A, serotype 1, 2 was isolated from all three cattle, and only P . haemolytica biotype T isolates were recovered from the bighorn sheep . One bighorn sheep died in each of the horse and cattle copasturing experiments . Pasteurella haemolytica was not isolated from the bighorn sheep which died in the horse copasturing experiment . A noncytotoxic P . haemolytica biotype A, serotype 2 was isolated at necropsy from the bighorn which died in the cattle contact experiment . Based on these experiments, we believe bighorn sheep and horse association would not be detrimental to bighorns due to P . haemolytica induced pneumonia.

J Wildl Dis, 1996 Oct, 32(4), 586 - 93
Susceptibility of Dall sheep (Ovis dalli dalli) to pneumonia caused by Pasteurella haemolytica; Foreyt WJ et al.; We evaluated susceptibility of Dall sheep (Ovis dalli dalli) to bacterial pneumonia induced by two strains of Pasteurella haemolytica of domestic sheep origin by evaluating the sensitivity of blood neutrophils of eight Dall sheep to lysis by cytotoxins of P . haemolytica, and by intratracheal inoculation of three Dall sheep, two bighorn sheep (Ovis canadensis), and two domestic sheep with 3.7 x 10(6) or 2.5 x 10(7) colony forming units of P . haemolytica . Neutrophils from the Dall sheep were more sensitive to lysis by cytotoxins from supernatants of a P . haemolytica, biotype A, serotype 2 (A2), of domestic sheep origin, than were neutrophils from six bighorn sheep . This cytotoxic bacterium was the same isolate that was used for intratracheal inoculation of two Dall sheep and two domestic sheep . Inoculation of this cytotoxic P . haemolytica A2 resulted in fatal fibrinopurulent pleuropneumonia in the first Dall sheep within 24 hr of inoculation, and pneumonic lesions in the second Dall sheep before it was euthanized 52 hr after inoculation . This strain of P . haemolytica A2 did not cause respiratory disease when inoculated into two domestic sheep . A noncytotoxic strain of P . haemolytica; biotype T, serotype 3,4,10 of domestic sheep origin did not result in pneumonia in the third Dall sheep or two bighorn sheep . Prior to inoculation, P . haemolytica, biotype T isolates were obtained from all three Dall sheep, but none of these isolates was cytotoxic . At necropsy, cytotoxic P . haemolytica A2 was isolated from lungs and other tissues of the two pneumonic Dall sheep . Based on these results, we conclude that Dall sheep appear to be at least as sensitive as bighorn sheep to pneumonia caused by P . haemolytica A2 of domestic sheep origin . Because in vitro and in vivo results appear closely correlated in this and other studies, we believe with additional evaluation and standardization, neutrophil cytotoxicity tests may serve as a substitute for live animal challenges in future studies of pathogenic P . haemolytica in wild sheep.

Avian Dis, 1997 Jul-Sep, 41(3), 676 - 82
Detection of Pasteurella multocida-specific DNA in turkey flocks by use of the polymerase chain reaction; Kasten RW et al.; A polymerase chain reaction (PCR)-based assay using primers constructed to amplify the gene (psl) encoding the P6-like protein (Psl) of Pasteurella multocida was developed . After Southern blotting and hybridization with psl, the assay (PCR-H) was found to be specific (it did not detect a variety of other avian bacterial pathogens) and sensitive (detected > or = 10 P . multocida organisms or > or = 24 femtograms of extracted P . multocida DNA) . Samples were collected from the oropharynx of randomly selected birds housed on premises that had recently experienced an outbreak of avian cholera (outbreak farms) or from birds housed on premises that had not reported an outbreak of this disease during the preceding 12 mo (control farms) . The PCR-H assay detected 11 infected turkeys out of a total of 178 sampled on six outbreak farms as compared with isolation of P . multocida from 23 turkeys by using mouse inoculation . Neither method detected P . multocida in samples collected from 174 turkeys sampled on six control farms . Statistical analysis using the Kappa test demonstrated that the results of the two tests showed poor agreement from five outbreak flocks (K = 0, 0, 0, 0.35, 0.47) and strong agreement from one outbreak flock (K = 0.89) . Combined results from the outbreak flocks showed poor agreement (K = 0.49) between the two methods.

Infect Immun, 1997 Nov, 65(11), 4502 - 8
Role of outer membrane protein H (OmpH)- and OmpA-specific monoclonal antibodies from hybridoma tumors in protection of mice against Pasteurella multocida; Vasfi Marandi M et al.; Two major outer membrane proteins of Pasteurella multocida, designated OmpH and OmpA, were characterized and shown to be related to the families of porin and heat-modifiable proteins, respectively . The backpack hybridoma tumor system in BALB/c mice was used to continuously deliver immunoglobulin G2b (IgG2b) monoclonal antibodies (MAbs) specific for OmpH (MAb MT1) and OmpA (MAb MT4.1) . MAbs were detected in serum and peritoneal lavage samples of mice bearing hybridoma tumors by an enzyme-linked immunosorbent assay and an immunoblot assay . Highly significant protection was observed in mice bearing MT1 hybridoma tumors against both intraperitoneal and intranasal challenge infections with homologous nontoxigenic P . multocida strains possessing MAb MT1-reacting epitopes, whereas the mice bearing MT4.1 hybridoma tumors were not protected . The numbers of P . multocida organisms in the lungs of mice bearing MT1 hybridoma tumors were significantly less than those in lungs of mice bearing MT4.1 hybridoma tumors at 48 h postchallenge . These results indicate that the OmpH-specific MAb inhibited proliferation of P . multocida in the lungs . MAb MT1 was unable to kill P . multocida in vitro in the presence of complement . However, an enhanced phagocytosis by polymorphonuclear cells (PMNs) was observed in mice bearing MT1 hybridoma tumors . P . multocida induced a more extensive and rapid influx of PMNs into the peritoneal cavity of mice bearing MT1 hybridoma tumors than of mice bearing MT4.1 hybridoma tumors . The results of this study demonstrate for the first time that IgG MAbs against OmpH of P . multocida are involved in the protection of mice against lethal challenge infection by means of opsonization and inhibition of proliferation of P . multocida as a result of increased influx of PMNs into the infection site.

J Comp Pathol, 1997 Aug, 117(2), 137 - 45
Influence of immunization on the pulmonary inflammatory response of rabbits induced by Pasteurella haemolytica A1 lipopolysaccharide; Ramirez-Romero R et al.; Immune complex formation has long been thought to play a role in the pathogenesis of Pasteurella haemolytica pneumonia . This study in laboratory rabbits was designed to investigate immune-mediated damage in respiratory tissue caused by lipopolysaccharide (LPS) . Severe lesions were induced by the intratracheal (IT) injection of P . haemolytica A1 LPS (50 micrograms) into rabbits previously immunized with P . haemolytica killed whole cells emulsified with Freund's incomplete adjuvant (FIA); these lesions included perivascular oedema and polymorphonuclear leucocyte (PMN) infiltration of the subintima, with degeneration and necrosis of the media . Smaller vessels were occluded by PMNs in various stages of degranulation . PMN counts in bronchoalveolar lavage (BAL) fluid were significantly elevated (P < 0.05) . Lesions were also induced by the IT injection of LPS (50 micrograms) into rabbits pretreated with an emulsion consisting merely of FIA and formol-saline; these lesions included moderate to severe congestion, interstitial oedema, alveolar serofibrinous exudation and PMN infiltration . PMNs were also present in BAL fluid . Rabbits pretreated with FIA in formol-saline and given a later IT injection of saline, and rabbits pretreated with bovine serum albumin (BSA) in FIA and given a later IT injection of BSA, were included as negative and positive control groups . Cutaneous lesions were also induced by the intradermal injection of LPS into rabbits immunized against P . haemolytica and of BSA into rabbits immunized with BSA . Overall, the pulmonary and cutaneous lesions induced in vaccinated rabbits by antigen administration were more severe than those seen in non-vaccinated rabbits . The lesions in rabbits, which were similar to those seen in natural cases of P . haemolytica pneumonia in cattle, were characterized by a fibrinopurulent inflammatory process with extensive interstitial oedema, fibrinous exudate, and PMNs . This model may help to elucidate the pathogenesis of pneumonic pasteurellosis in immunized animals.

FEMS Microbiol Lett, 1997 Oct 15, 155(2), 203 - 7
Protection against haemorrhagic septicaemia induced by vaccination of buffalo calves with an improved oil adjuvant vaccine; Shah NH et al.; An experimental oil adjuvant vaccine was developed against haemorrhagic septicaemia, a disease of cattle and buffalo caused by Pasteurella multocida serotype B and E . Mineral oil, Mercol 52, was used as adjuvant together with Span 85 and Tween 85 as emulsifiers . The vaccine was evaluated by single dose intramuscular immunisation of 1-2 year old buffalo calves . IgG and IgM class antibodies were determined by ELISA . The group of animals immunised with the experimental oil adjuvant vaccine showed a high titre of the IgG class of antibodies measured at 300 days post vaccination . To compare the protective efficacy of the vaccine with the commonly used broth bacterin, another group of buffalo calves was immunised by broth bacterin . This group showed a low level of IgG antibodies . Protection was assessed by challenge with 10(9) viable bacteria of P . multocida type B:2,5 administered subcutaneously, 250 days post vaccination . Animals vaccinated with the experimental oil adjuvant vaccine were fully protected . The other groups of animals, vaccinated with broth bacterin or used as control (non-vaccinated), developed symptoms of haemorrhagic septicaemia . A strong relationship between IgG but not IgM class antibody level and resistance to challenge was observed . The experiment demonstrated that the experimental oil adjuvant vaccine was superior to broth bacterin in providing protection against experimental haemorrhagic septicaemia in young buffalo calves beyond 250 days.

Vet Pathol, 1997 Sep, 34(5), 421 - 30
Effects of Pasteurella multocida toxin on porcine bone marrow cell differentiation into osteoclasts and osteoblasts; Gwaltney SM et al.; The effect of Pasteurella multocida toxin (PMT) on porcine osteoclast and osteoblast differentiation was studied using in vitro cell culture systems . When grown in the presence of Vitamin D3, isolated porcine bone marrow cells formed multinucleated cells with features characteristic of osteoclasts . Exposure of bone marrow cells to Vitamin D3 and PMT during growth resulted in formation of increased numbers and earlier appearance of osteoclasts compared to controls . Ultrafiltered medium form PMT-treated cells likewise increased osteoclast numbers, suggesting that a soluble mediator may be involved in the action of PMT . When cell cultures were treated with fluorescein-labeled PMT, fluorescence was found within the cytoplasm of small, round cells that did not resemble either osteoclasts or osteoclastic precursor cells . Cultures of porcine bone marrow cells exposed to dexamethasone, ascorbic acid, and beta-glycerophosphate developed into osteoblastic cells that formed multilayered, mineralized nodules . Exposure of osteoblastic cultures to low concentration of PMT resulted in retarded cell growth, formation of decreased numbers of nodules and minimal to no mineralization in the nodules; higher concentration of PMT resulted in increased cellular debris and poor growth of cells, with no nodule formation . These findings suggest that PMT may induce turbinate atrophy in pigs by increasing osteoclast numbers and inhibiting osteoblastic bone formation . The effect of PMT on osteoclastic differentiation and growth may not be due to a direct effect on preosteoclastic cells, but rather due to alterations in the soluble mediator secretion by marrow stromal cells.

Am J Pathol, 1997 Oct, 151(4), 1009 - 17
Respiratory infection in lipid-fed rabbits enhances sudanophilia and the expression of VCAM-1; Richardson M et al.; The pathogenesis of atherosclerosis has been related to infection of the arterial wall, but it is not clear whether this occurs before or after the development of lipid-containing lesions . Respiratory bacterial infection increases the expression of vascular cell adhesion molecule-1 (VCAM-1) . We therefore examined whether a similar infection would enhance atherosclerosis in New Zealand White rabbits fed chow supplemented by 15% (w/w) egg yolk for 50 days . Rabbits with naturally acquired respiratory infection by Pasteurella multocida, pathogen-free (SPF) animals infected by P . multocida in the laboratory, and age-matched SPF rabbits maintained in a disease-free environment were used . Endothelial cells expressing VCAM-1 in the aorta between intercostal arteries 3 and 5 were identified using anti-VCAM-1 (Rb1/9) and an alkaline-phosphatase-linked secondary antibody and quantified in Hautchen preparations . The remainder of the aorta was stained with Sudan IV to show lipid deposition . The expression of VCAM-1 (mean +/- SEM per 10,000 cells) was 22 +/- 8 (n = 5) in the lipid-fed SPF rabbits, significantly different from that in the lipid-fed rabbits with naturally occurring infection (190 +/- 51 (n = 5)) or from rabbits infected in the laboratory (106 +/- 25 (n = 5)) . The extent of Sudanophilia was significantly greater in the naturally infected rabbits (8.3 +/- 1.2%) or infected SPF rabbits (10.3 +/- 1.8%) than in the SPF rabbits (2.7 +/- 0.8%; P < 0.05) . Antibiotic treatment in naturally infected rabbits reduced the number of cells expressing VCAM-1 and the extent of the Sudanophilia to baseline levels . Thus, Sudanophilia is enhanced by bacterial infection in rabbits fed egg yolk and is associated with a significant increase in VCAM-1.

Equine Vet J, 1997 Sep, 29(5), 394 - 9
Bacterial endocarditis in horses: ten cases (1984-1995); Maxson AD et al.; A retrospective study of 10 horses with bacterial endocarditis was performed in order to describe the echocardiographic findings in horses with bacterial endocarditis, in conjunction with clinical signs and post mortem findings, and to evaluate the usefulness and the formulation of a prognosis . Echocardiographic and post mortem examinations were performed in 7 horses . Post mortem examination alone was performed in 2 horses and echocardiographic examination alone performed in one horse . No breed or sex predilection was obvious . Mean age +/- s.d . was 2.12 +/- 3.32 years . Predominant clinical signs and abnormal clinical pathology data were fever, cardiac murmur, tachycardia, tachypnoea, hyperfibrinogenaemia, anaemia and leucocytosis . Pasteurella/Actinobacillus spp . and Streptococcus spp . were most commonly cultured . Vegetative lesions were found most frequently on the mitral valve and secondarily on the aortic valve . The location and number of lesions identified with echocardiography in the horses accurately described the lesions found on post mortem examination . Medical treatment was attempted in 50% of the horses . Serial echocardiography was used to assess the response to treatment in 2 horses . All horses with vegetative lesions of the mitral and/or aortic valve died or were subjected to euthanasia due to the severity of their cardiac disease . Both horses with tricuspid valve endocarditis were cured of the infection, one horse returned to racing after antimicrobial therapy and the other was subjected to euthanasia due to severe laminitis.

Curr Microbiol, 1997 Nov, 35(5), 316 - 8
Isolation of Pasteurella haemolytica from grass, drinking water, and straw bedding used by sheep; Burriel AR; Pasteurella haemolytica was isolated from three of 18 grass samples and four of 18 water samples collected from two grazing fields occupied by sheep . This microorganism was also isolated from three of nine straw bedding samples collected from a pen housing ewes affected by mastitis caused by P . haemolytica . The same ewes developed scabbed papilloma-like lesions on the teat and udder skin . These lesions were colonized by P . haemolytica of various serotypes . Colder, wetter weather seems to prolong the survival of P . haemolytica in the environment of sheep . Survival of virulent strains of P . haemolytica in the environment could accumulatively increase the bacterial count, contributing to their transmission from animal to animal . The preference of P . haemolytica for colder, wetter conditions was confirmed in the laboratory where this microorganism survived longer in distilled water, phosphate-buffered saline, Todd-Hewitt broth, and ewe's milk kept at 4 degrees C.

Dtsch Tierarztl Wochenschr, 1996 Dec, 103(12), 513 - 6
{Importance of blood serological examinations in the context of rhinitis atrophicans diagnosis}; Muller E et al.; In a period of three years in 95 breeding-herds, which were free from Rhinitis atrophicans (R . a.), 5001 blood-samples were examined . All samples were examined by the SNT/EBL-cell-culture-test-mostly however by the SNT/ELISA-system- and were free of antibodies against R . a . On the contrary in 6 herds, that had bought swines from latent infected populations, antibodies against the toxin could be found before clinical signs were to be seen and before toxin producing pasteurellas could be discovered, too . In other 4 herds antibodies against R . a . could be found . In the last mentioned herds R . a . was suspected by clinical, bacteriological and pathomorphological examinations . The serological determination of blood may replace the provement of the diameter of the nose by pathomorphological diagnosis . The serological investigation is a good test . After positive results of antibodies comprehensive bacteriological tests should follow . This can be integrated in the diagnostical system of R . a . very easily, because enough blood samples will be taken ordered by the official examinations for European Swinefever- and Aujeszky-disease.

Cell Stress Chaperones, 1997 Sep, 2(3), 180 - 90
Refolding of recombinant Pasteurella haemolytica A1 glycoprotease expressed in an Escherichia coli thioredoxin gene fusion system; Watt MA et al.; Pasteurella haemolytica A1 secretes an O-sialoglycoprotein endopeptidase (EC . 3.4.24.57) (glycoprotease: Gcp) which is specific for O-linked sialoglycoproteins . When the cloned gene is expressed in Escherichia coli, the recombinant glycoprotease (rGcp) is secreted to the periplasm where it is present as a disulfide-linked aggregate which lacks enzymatic activity . In vitro refolding and activation of rGcp by mammalian protein disulfide isomerase (PDI) or by the E . coli chaperones (DnaK, DnaJ and GrpE) indicate that the redox environment of rGcp is critical in restoring biological activity . A fusion protein, rTrx-Gcp, was constructed to investigate the role of thioredoxin (E . coli TrxA) in the production of enzymatically active rGcp . This 47 kDa protein was expressed at a high level, in a soluble, monomeric form, in the cytoplasm of E . coli . Cleavage of the fusion protein by enterokinase released the rGcp fragment (35 kDa) with glycoprotease activity . A higher recombinant glycoprotease activity was recovered after anion exchange chromatography of lysates of E . coli expressing rTrx-Gcp . Thus when E . coli TrxA is combined in a recombinant fusion protein with P . haemolytica A1 Gcp, productive folding of the glycoprotease can occur as a result of the chaperone action of the protein disulfide reductase coupled with its ability to retain the fusion gene product in the E . coli cytoplasm.

Zh Mikrobiol Epidemiol Immunobiol, 1997 May-Jun, (3), 15 - 9
{The cultural and morphological properties of different serovariants of Pasteurella multocida when cultured in nutrient broths of different compositions}; Popova TE; The results of the study of the cultural morphological properties and growth dynamics of P . multocida, serotypes A, B, D, in the course of cultivation in liquid media are presented . The bacteria were grown in synthetic nutrient medium 199 and Hottinger broth . The influence of glucose at different concentrations on the growth activity of P . multocida in the synthetic medium was established . The process of the accumulation of surface (capsular) antigens in culture fluid was studied . The levels of the titers of surface antigens were shown to depend on the growth phases of bacteria.

Vaccine, 1997 Aug-Sep, 15(12-13), 1423 - 9
Serum antibody responses of cattle vaccinated with partially purified native Pasteurella haemolytica leukotoxin; Confer AW et al.; The objective of these experiments was to study the serum antibody responses of cattle to partially purified, native Pasteurella haemolytica A1 leukotoxin (LKT) formulated with a commercial aluminum hydroxide-DDA-bromide adjuvant . In two experiments, calves received two intramuscular injections 21 days apart and sera were obtained periodically . Serum antibody responses to P . haemolytica outer membrane proteins (OMPs), formalinized P . haemolytica, and LKT were determined . In Experiment A, Holstein calves (140 kg each) were vaccinated with either 10, 1.0 or 0.1 micrograms of LKT, 10(9) c.f.u . of live P . haemolytica, or adjuvanted diluent . In Experiment B, mixed-breed beef calves (200 kg each) were vaccinated with either 100, 50 or 10 micrograms of LKT, 10(9) c.f.u . live P . haemolytica, or adjuvanted diluent . Vaccination of dairy calves with 10 micrograms of partially purified LKT stimulated LKT neutralizing antibody responses similar to those stimulated by vaccination of one calf with live P . haemolytica . In Experiment B, which used larger and different breeds of cattle, two vaccinations 3 weeks apart with 50 micrograms LKT stimulated LKT neutralizing responses equivalent to or greater than those stimulated by vaccination with live P . haemolytica . In both experiments, LKT vaccines stimulated only low antibody responses to formalinized P . haemolytica or to OMPs.

J S Afr Vet Assoc, 1997 Jun, 68(2), 55 - 8
Efficacy of doxycycline in a goat model of Pasteurella pneumonia; Ole-Mapenay IM et al.; The clinical efficacy of doxycycline (Doxycen, Cenavisa, Spain), a long-acting preparation, was evaluated for treatment of Pasteurella haemolytica infection in 6 goats . One goat was not infected and served as a control . The disease was induced by intratracheal inoculation of 10(7) to 10(9) cfu of P . haemolytica . Confirmation of respiratory disease was based on evidence of appropriate clinical signs . Before and after initiation of doxycycline treatment on day 10, each goat was examined daily . Three clinical responses to doxycycline treatment were noted . Mean rectal temperatures decreased from 40.1 degrees C to normal, while mean respiratory rate decreased from the pre-treatment value of 32 to 27/min after 4 days . Other clinical signs associated with pneumonia resolved within 3-5 days post treatment . In addition the minimum inhibitory concentration of DOTC for the P . haemolytica isolate was found to be < 0.5 microgram/ml . The present study indicates that DOTC may be a useful antimicrobial agent in the treatment of caprine pasteurellosis.

Infect Immun, 1997 Sep, 65(9), 3970 - 5
A putative leucine zipper activator of Pasteurella haemolytica leukotoxin transcription and the potential for modulation of its synthesis by slipped-strand mispairing; Highlander SK et al.; A Pasteurella haemolytica cosmid clone that activates leukotoxin transcription in Escherichia coli has been isolated . The activator locus, alxA, is part of a continuous open reading frame that includes the type I hsdM methylase gene . AlxA and HsdM peptides are processed from a precursor, and translation of the polyprotein can be modulated by slipped-strand mispairing across a pentanucleotide repeat, ACAGC, within the 5' end of alxA-hsdM . Extracts containing AlxA can bind to a leukotoxin promoter fragment.

Infect Immun, 1997 Sep, 65(9), 3719 - 24
Binding of Pasteurella haemolytica leukotoxin to bovine leukocytes; Brown JF et al.; Pasteurella haemolytica is the principal bacterial pathogen in the bovine respiratory disease complex . This organism produces an exotoxin (referred to as leukotoxin) during logarithmic-phase growth that is a potent leukocyte-modulating agent . At low concentrations, it activates neutrophils and mononuclear phagocytes to release inflammatory mediators, while at the same time making these cells destined to undergo apoptotic cell death . At higher concentrations, the toxin causes rapid swelling and loss of cell viability . In this study, we demonstrated that toxin binding can be directly evaluated by flow cytometry with biologically active biotinylated leukotoxin . Leukotoxin binding was blocked by the addition of a neutralizing anti-leukotoxin monoclonal antibody and was not detected when bovine leukocytes were incubated with culture filtrates from a mutant strain of P . haemolytica that does not produce biologically active leukotoxin . In addition, treatment of bovine leukocytes with protease K eliminated subsequent binding of leukotoxin, suggesting that there is a protein on the leukocyte surface that is either a leukotoxin binding site or is required for stabilization of leukotoxin binding . We did not detect binding of biotinylated leukotoxin to porcine or human leukocytes, which have been reported previously to be resistant to the lytic effects of the leukotoxin . These findings suggest that there may be a specific binding site for P . haemolytica leukotoxin on bovine but not on porcine or human leukocytes and that it might be involved in the activation and lytic activities of the leukotoxin.

Infect Immun, 1997 Sep, 65(9), 3585 - 93
Evolutionary genetics of Pasteurella haemolytica isolates recovered from cattle and sheep; Davies RL et al.; Genetic diversity and relationships among 194 Pasteurella haemolytica isolates, which were recovered predominantly from cattle (39%) and sheep (58%) suffering from pneumonic pasteurellosis in the United Kingdom, Germany, and the United States, were estimated by examination of allelic variation at 18 enzyme-encoding loci detected by multilocus enzyme electrophoresis . The isolates formed two major divisions . One included 178 Pasteurella haemolytica sensu stricto strains representing serotypes A1, A2, A5 to A9, A12 to A14, and A16; the other was composed of 16 isolates belonging to the A11 taxon . P . haemolytica isolates were classified into 22 electrophoretic types (ETs) that formed three primary phylogenetic lineages . One lineage was represented by ovine serotype A2 isolates, a second lineage consisted of bovine serotype A2, together with serotype A7 and A13 isolates, and the third lineage included isolates representing all of the other serotypes, as well as a second group of serotype A7 strains . Electrophoretic types were nonrandomly associated with specific capsular serotypes, lipopolysaccharide (LPS) types, outer membrane protein (OMP) types, and host species . Bovine isolates were represented by only three serotypes (A1, A2, and A6) in 5 ETs, whereas ovine isolates were represented by all of the serotypes in 19 ETs . The majority (76%) of bovine isolates were of serotypes A1 or A6 and belonged to a single ET that marked a virulent, cattle-specific clonal group . Among the ovine isolates, 40% were of serotype A2 and belonged to two ETs that represented two virulent, sheep-specific clonal groups . Bovine A1 and A6 isolates and bovine A2 isolates were phylogenetically distinct from ovine isolates of the same serotypes, indicating that different subpopulations of these serotypes are associated with disease in cattle and sheep . Consistent differences in the OMP profiles of strains of the bovine and ovine lineages of these three serotypes suggest that certain OMPs are involved in host specificity and virulence . Evolutionary relationships among P . haemolytica isolates indicate that the ancestral host is the sheep and that several distinct clonal lineages have crossed the species barrier into cattle . The A11 taxon is a heterogeneous group of opportunistic pathogens of sheep that represents a separate species.

Poult Sci, 1997 Sep, 76(9), 1248 - 55
Application of a nonlinear regression function to evaluate the kinetics of antibody response to vaccines in chicken lines divergently selected for multitrait immune response; Weigend S et al.; To evaluate the kinetics of immune response to vaccines in chickens, antibody response curves were approximated to the observed antibody ratios by using a nonlinear regression function . New parameters, the curve maximum (ymax) and the time of the maximum (tmax), were calculated . The method was applied to analyze the kinetics of the serum antibody response to Mycoplasma gallisepticum (MG) and Pasteurella multocida (PM) vaccines in White Leghorn lines selected, in replicate, for 10 generations for high (High) and low (Low) multitrait immune response . Chicks were immunized at 6 wk of age with both vaccines . Serum antibody levels were analyzed before (0) and 1, 2, 3, 4, 5, 12, and 21 wk postvaccination (wpv) . The High lines displayed a significantly higher response than Low to both MG and PM . The difference in ymax between High and Low lines was 3.25-fold for PM response and 1.5-fold for MG response . Low lines had a significantly (P < 0.05) later tmax than High lines to MG, but not to PM . There was a significant (P < 0.05) positive correlation between the antibody responses to MG and PM, in High lines for the antibody ratios 0, 3, and 21 wpv and in Low lines for 0, 12, and 21 wpv . The ymax and tmax of antibody responses to the two vaccines were not correlated . The results on the kinetic differences of the antibody responses to MG and PM suggest that the kinetics and persistence of antibody reaction have different genetic regulation in response to each vaccine.

Proc Natl Acad Sci U S A, 1997 Aug 5, 94(16), 8686 - 90
Epithelial antibiotic induced in states of disease; Stolzenberg ED et al.; Epithelial defensins provide an active defense against the external microbial environment . We investigated the distribution and expression of this class of antimicrobial peptides in normal cattle and in animals in varying states of disease . beta-defensin mRNA was found to be widely expressed in numerous exposed epithelia but was found at higher levels in tissues that are constantly exposed to and colonized by microorganisms . We observed induction in ileal mucosa during chronic infection with Mycobacterium paratuberculosis and in bronchial epithelium after acute infection with Pasteurella haemolytica . It has been proposed that expression of antimicrobial peptides is an integral component of the inflammatory response . The results reported here support this hypothesis and suggest that epithelial defensins provide a rapidly mobilized local defense against infectious organisms.

Vaccine, 1997 Aug, 15(11), 1254 - 60
Protection, humoral and cell-mediated immune responses in calves immunized with multiple emulsion haemorrhagic septicaemia vaccine; Verma R et al.; A multiple emulsion (ME), vaccine against Pasteurella multocida (P52) infection in cattle was prepared and the efficiency in terms of immunity to direct challenge, duration of this immunity for up to 1 year and the role of humoral and cell-mediated immune mechanisms were studied . ME vaccine was sterile, safe and was potent when tested in rabbits and calves . Nineteen calves were immunized with a single 4 ml dose of ME vaccine intramuscularly . Group of these calves were challenge infected with virulent P . multocida (P52) (10(-1) 18 h old broth culture) given by the subcutaneous route at 21 days, 3 months, 6 months, 9 months and 1 year . All the immunized calves withstood challenge infection and showed 100% protection . Humoral immune response was measured by indirect haemagglutination test (IHA) and enzyme-linked immunosorbant assay (ELISA) . Statistically ELISA values were found to be superior to IHA values because of small coefficient of variance . A fall in mean antibody titres during 24 h, 48 h, post-challenge infection was recorded whereas a steady increase in the titre after 72 h up to 10 days was noticed . The prechallenge mean titre in animals correlated with survival of animals . Humoral antibodies were detected as early as 7 day post-immunization and persisted to 1 year after immunization . Leucocyte migration inhibition test showed > 20% migration inhibition during all pre- and post-challenge periods in animals suggesting an involvement of cell-mediated immune mechanism in protection . Our findings suggested that both humoral and cell-mediated immune responses contribute to protection in vaccinated animals . The results of these studies of ME vaccine showed that it can be successfully used for the effective control of haemorrhagic septicaemia.

Microbiology, 1997 Aug, 143 ( Pt 8), 2841 - 9
Genetic relationships among Pasteurella trehalosi isolates based on multilocus enzyme electrophoresis; Davies RL et al.; Genetic diversity among 60 British Pasteurella trehalosi isolates representing the four recognized capsular serotypes, T3, T4, T10 and T15, and recovered predominantly from sheep suffering from systemic pasteurellosis, was estimated by analysing electrophoretically demonstrable allelic variation at structural genes encoding 19 enzymes . Thirteen of the locl were polymorphic and 20 distinctive multilocus genotypes (electrophoretic types, ETs) were identified . The population structure of P . trehalosi is clonal and its genetic diversity is limited compared with most other pathogenic bacteria . ETs represent clones, and isolates of the same ET were generally associated with the same combination of serotype, LPS type and outer-membrane protein (OMP) type . The genetic diversity of isolates within each of the capsular serotypes varied . Serotype T10 was represented by 18 isolates in two related ETs and exhibited little diversity . By contrast, serotype T15 was represented by 18 isolates in nine ETs and was almost as diverse as the species as a whole Serotype T4 was represented by 18 isolates in five ETs and was less diverse than serotype T15 . Although serotype T3 was more diverse than serotype T15 it was represented by only three isolates . With the exception of the T10 isolates and those recovered from healthy sheep, 35 disease isolates belonged to 16 ETs, each of which was represented by only one to four isolates . The fact that a high proportion of disease is caused by a relatively large number of clones suggests that P . trehalosi is essentially an opportunistic pathogen . In addition to having the same capsular structure, isolates belonging to the two T10 clones were characterized by possession of similar, if not identical, O-antigens (LPS types 2 and 4) . The occurrence of 18 serotype T10 isolates in only two ETs suggests that the T10 capsule and type 2/4 O-antigen confer enhanced virulence on members of these two clones . Multilocus enzyme electrophoresis (MLEE) had greater resolving power than did capsule/LPS/OMP analysis, being able to distinguish 20 rather than 14 sub-divisions within P . trehalosi . The technique demonstrated genetic identity or non-identity among strains of the same or different serotypes from different geographic localities within the UK and was a useful epidemiological tool.

Vet Res Commun, 1997 Aug, 21(6), 453 - 62
Aspects of the pharmacokinetics of doxycycline given to healthy and pneumonic East African dwarf goats by intramuscular injection; Ole-Mapenay IM et al.; The effect of experimentally induced Pasteurella haemolytica pneumonia on the pharmacokinetics of doxycycline (Doxycen Retard) administered intramuscularly was studied in seven East African dwarf goats . The study was conducted in two consecutive phases, separated by a washout period of four weeks . The experimental infection, induced by intratracheal administration of 5 ml of 10(7) to 10(9) cfu/ml of Pasteurella haemolytica, produced a temperature rise, depression and laboured breathing within 6-12 days after inoculation . The concentrations of doxycycline in the serum were determined by a quantitative microbiological assay using an agar-gel diffusion method employing Bacillus cereus var mycoides (ATCC 11778) as the test organism, with a level of detectability of approximately 0.05 micrograms/ml . The concentration-time curve of doxycycline in the serum after intramuscular injection of 20 mg/kg bodyweight of the long-acting formulation before and after experimental infection was adequately described by a one-compartment open model . The maximum serum concentrations (Cmax) of doxycycline were lower in pneumonic goats than in healthy goats (3.87 +/- 0.52 and 5.56 +/- 0.213 micrograms/ml, respectively), suggesting an increased distribution volume in the peripheral compartment . The mean +/- SEM absorption rate (ka) before infection (1.13 +/- 0.02 h-1) was smaller than the after infection (8.23 +/- 3.81 h-1), but the difference was not significant . The apparent elimination half-life (t 1/2 beta) (24.51 +/- 0.02 h) after infection was significantly increased (p < 0.05), while the corresponding rate constant (beta) was decreased (p < 0.01) . The absorption half-life (t 1/2(alpha)) (0.137 +/- 0.03 h) was significantly decreased (p < 0.01) after infection . The distribution volume (Vd(beta)) was significantly increased after infection (p < 0.05) . It is concluded that, although experimental infection had an effect on the disposition kinetics of doxycycline, this was not sufficiently pronounced to require alteration of the dosage during disease.

Vet Res Commun, 1997 Aug, 21(6), 421 - 30
Bacterial identity and characteristics in healthy and unhealthy respiratory tracts of sheep and calves; Barbour EK et al.; The aim of this study was to compare different bacteriological aspects of the respiratory systems of healthy (H) versus unhealthy (UH) animals with respiratory signs . The prevalence of different bacterial species was determined in the upper and lower respiratory tract of H and UH Najdi sheep, Somali sheep and Holstein calves . The characteristics of Pasteurella spp . isolates, and the biotype of Pasteurella haemolytica were identified in H and UH animals, Eighteen out of 28 (64.3%) of the identified bacterial species in the upper respiratory tract were more prevalent in the nasal cavities of UH Najdi and Somali sheep and Holstein calves with respiratory signs than in apparently healthy animals; four of the most prevalent bacteria in the upper respiratory system of UH sheep were Moraxella spp., Pseudomonas pseudomallei, Erysipelothrix spp., Pasteurella multocida, while three of the most prevalent bacteria in UH calves were Pasteurella haemolytica, Actinomyces spp., and Pseudomonas aeruginosa . The prevalence of six different bacterial species was greater in the lungs of UH animals, namely Actinomyces pyogenes, Erysipelothrix spp., P . haemolytica, Pasteurella ureae, Staphylococcus aureus, and Staphylococcus epidermidis, which could be risk factors in the complexity of the prevalent respiratory diseases of the animals surveyed . Of the biochemical, cytological and colonial characteristics studied in the identified P . haemolytica and P . multocida, two characters were significantly different (p < 0.05) in organisms isolated from UH as compared to those from H animals . These were the higher loss of haemolytic power by the strains of P . haemolytica and the decreased fermentation of trehalose by all the strains of P . multocida recovered from healthy animals . The only biotype of P . haemolytica isolated from H animals was biotype A, while both biotypes A (88.0% of the isolates) and T (12.0% of the isolates) were recovered from UH animals.

J Rheumatol, 1997 Aug, 24(8), 1649 - 52
Pasteurella multocida infectious arthritis with acute gout after a cat bite; Butt TS et al.; A 74-year-old man with chronic lymphocytic leukemia, immune purpura, and gout presented with a painful, swollen ankle after a cat bite to his leg . On aspiration of the ankle, gram negative pleomorphic rods and monosodium urate crystals were seen and Pasteurella multocida was cultured . He was treated with ampicillin/sulbactam, joint aspiration, and intraarticular steroids, with resolution of infection and return of joint function . The syndromes of Pasteurella arthritis and crystal arthropathy with septic arthritis are reviewed.

Am J Vet Res, 1997 Aug, 58(8), 841 - 7
Efficacy of a subcutaneously administered, ultraviolet light-killed Pasteurella multocida A:3-containing bacterin against transthoracic challenge exposure in goats; Purdy CW et al.; OBJECTIVE: To determine the effectiveness of Pasteurella multocida biovar A, serovar 3 (Pm A:3) killed by exposure to UV light and incorporated with a polyacrylate bead carrier as a vaccine . ANIMALS: 18 weanling male Spanish goats . PROCEDURE: Prospective, randomized controlled study with 3 treatment groups: positive-control (PC), negative-control (NC), and principal Pm A:3 bacterin (PA) groups . Six PC goats each received live Pm A:3 and polyacrylate beads twice, 22 days apart, by transthoracic injection into the left lung . Six NC goats each received only PA beads twice, 22 days apart, by transthoracic injection . Six principal goats each received Pm A:3 vaccine SC twice, 22 days apart . Fourteen days after the second vaccination, all goats were challenge exposed with live Pm A:3 by transthoracic injection into the right lung, and 4 days later they were euthanatized and necropsied . RESULTS: Mean volume of consolidated lung tissue at the challenge site was 1.75 cm3 for the PC group, 15.18 cm3 for the NC group, and 3.9 cm3 for the PA vaccine group . The NC group had a significantly (P < or = 0.002) larger mean volume of consolidated lung tissue than did the PC and PA groups after challenge exposure . CONCLUSIONS: The PA bacterin and the PC groups developed protective immunity against live Pm A:3 challenge exposure . An SC administered, UV light-killed, Pm A:3 bacterin induced protective immunity similar to that induced by virulent live Pm A:3 injected into the target organ, the lung.

J Clin Microbiol, 1997 Aug, 35(8), 1948 - 51
Evaluation of transport media for Pasteurella multocida isolates from rabbit nasal specimens; Kawamoto E et al.; A suitable medium for the transport of Pasteurella multocida in nasal specimens from rabbits was investigated by using pure cultures of the organism and nasal swabs from infected rabbits . First, the ability of eight transport media to preserve the viabilities of P . multocida strains isolated from rabbits was studied . Cary-Blair medium and Leibovitz medium no . 15 (L-15) were found to be superior to the other six media tested, enabling survival of the organism for more than 14 days at room temperature . Second, the survival of P . multocida in nasal specimens was evaluated on both Cary-Blair medium and L-15 . The recovery rate of the organism from these two media was more than 80 to 90% during 4 days of storage and decreased gradually with increasing preservation time . There were no significant differences (P > 0.05) in recovery rates of the organism between Cary-Blair medium and L-15 . On the basis of these results, we recommend the use of Cary-Blair medium for the transport of P . multocida in rabbit nasal specimens because of the ease of transport of nasal swabs by mail.

Vet Rec, 1997 Jul 12, 141(2), 37 - 40
Comparative in vitro activity of doxycycline and oxytetracycline against porcine respiratory pathogens; Bousquet E et al.; Minimum inhibitory concentrations of doxycycline and oxytetracycline were determined against 55 Pasteurella multocida strains, 59 Actinobacillus pleuropneumoniae strains and 26 Mycoplasma hyopneumoniae strains isolated from the respiratory tract of pigs . An additional set of 76 P multocida strains isolated from pneumonic pigs was tested for their minimum inhibitory concentrations of doxycycline . The P multocida and A pleuropneumoniae strains were isolated in France and the minimum inhibitory concentrations were determined by an agar dilution method . The M hyopneumoniae strains were isolated in the United Kingdom and minimum inhibitory concentrations were determined by a serial broth dilution method . All the strains tested were susceptible to doxycycline whereas 15 per cent of the P multocida strains and 22 per cent of the A pleuropneumoniae strains were resistant to oxytetracycline . Doxycycline concentrations inhibiting 90 per cent of strains were 1 microgram/ml for P multocida and 2 micrograms/ml for A pleuropneumoniae . The ratio of the minimum inhibitory concentrations of doxycycline and oxytetracycline ranged between 1/1 and 1/4 for the oxytetracycline-susceptible strains and between 1/16 and 1/64 for the oxytetracycline-resistant strains . All the M hyopneumoniae strains were susceptible to doxycycline and oxytetracycline, the concentrations inhibiting 90 per cent of strains being 1 microgram/ml and 2 micrograms/ml, respectively . These data confirm that doxycycline has a higher in vitro activity against pig respiratory pathogens than oxytetracycline.

J Comp Pathol, 1997 Jul, 117(1), 73 - 82
Effects of Trypanosoma evansi on the output of cells from a lymph node draining the site of Pasteurella haemolytica vaccine administration; Onah DN et al.; The prefemoral efferent lymphatics of sheep infected with Trypanosoma evansi and inoculated with P . haemolytica vaccine and of those given only the vaccine, were surgically cannulated to study the effects of the infection on the total cellular output and output of blast cells from the node in response to the vaccine . T . evansi delayed and depressed the increases in total cell and lymphoblast outputs . In uninfected sheep, the total cellular output increased and peaked at more than twice the prevaccination values on days 4 and 5 after primary vaccination, but the increases were smaller and peaked on days 6 and 8 after primary vaccination in the infected sheep . The output of lymphoblasts mirrored the total cell output, though it was suppressed to a greater degree by T . evansi . The output of blasts peaked at more than 8 and 14 times the prevaccination values in the uninfected animals after primary and secondary (booster) vaccinations, respectively; but in infected animals, it peaked at twice the prevaccination values after the primary vaccination and showed no increase after booster vaccination until 11 days later . It is concluded that the inhibition of total and blast cell outputs by T . evansi may limit the early systemic dissemination of antigen-specific cells, thus playing a role in the induction of immunosuppression by the parasite.

Vet Immunol Immunopathol, 1997 Jul, 57(3-4), 279 - 87
Heterogeneity of porcine alveolar macrophages in experimental pneumonia; Berndt A et al.; The aim of the study was the morphological and the phenotypic characterization of the porcine non-lymphocytic bronchoalveolar lavage (BAL) cell population of unaffected- and intrabronchial with Pasteurella multocida- (P.m.) infected swine using flow cytometry . Three non-lymphocytic cell populations of the porcine bronchoalveolar lavage could be differentiated: (1) large, high autofluorescent cells, (LHC); (2) small, high autofluorescent cells, (SHC); (3) small, low autofluorescent cells, (SLC) . In comparison with the control animals, the percentage of the LHC and SHC within the whole non-lymphocytic cell population was decreased, whereas the SLC was significantly enhanced after infection . In order to investigate the phenotype of these cell populations, monoclonal antibodies against porcine antigens (SWC1, SWC3a, MHC class II, 2G6 (against macrophages)) were used . The results showed that the cells of the SLC seem to belong to the granulocytes, whereas the LHC and the SHC are lung macrophages . After the infection of the animals the percentage of the SWC1 positive cells of LHC and SHC were significantly increased, indicating an entrance of more immature macrophages . The percentage of the MHC class II antibody binding cells of all three non-lymphocytic populations was-decreased after infection, indicating a restricted MHC class II dependent antigen recognition in P.m . pneumonia.

J Wildl Dis, 1997 Jul, 33(3), 558 - 66
Effect of simulated stress on susceptibility of bighorn sheep neutrophils to Pasteurella haemolytica leukotoxin; Kraabel BJ et al.; We examined the effects of simulated stress on susceptibility of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) neutrophils to Pasteurella haemolytica leukotoxin in a blocked, crossover experiment . Ten captive-raised bighorn sheep were sampled 10 hr after separate administrations of long-acting adrenocorticotrophic hormone (ACTH) gel and normal saline (control) . We then compared in vitro leukotoxin-dependent neutrophil death rates after exposure to culture supernatants from four unique P . haemolytica isolates (one from domestic and three from bighorn sheep) . Simulated stress effects were evidenced by elevated (P = 0.002) mean plasma cortisol concentrations, more neutrophils (P = 0.037), and fewer lymphocytes and eosinophils (P < or = 0.043) in ACTH-treated bighorn sheep . Maximum leukotoxin-dependent neutrophil death rates were > or = 61% for three of four P . haemolytica isolates tested . For all three cytotoxic isolates, neutrophil death rates at 150 micrograms/50 microliters supernatant were about 1.13 times higher (P = 0.0001) after bighorns received ACTH; for two of these, overall neutrophil death rates were higher (P < or = 0.001) in ACTH-treated bighorn sheep . Although variable leukotoxin production among P . haemolytica strains appeared principally responsible for differences in leukotoxin-dependent neutrophil death rates, susceptibility of bighorn sheep neutrophils to leukotoxin was increased by prior exposure to elevated plasma cortisol concentrations . It follows that if similar processes occur in neutrophils and alveolar macrophages in vivo, they could contribute to greater susceptibility of stressed bighorn sheep to pneumonic pasteurellosis.

J Wildl Dis, 1997 Jul, 33(3), 544 - 57
Pasteurella spp . in sympatric bighorn and domestic sheep; Ward AC et al.; Domestic sheep were sighted at different times from 1991 to 1993 on four Nevada (USA) ranges occupied by bighorn sheep . Nasal and pharyngeal swab samples were collected from both sheep species and cultured to determine if any strains of Pasteurella spp . were shared on range conditions after contact of the two species . Pasteurella spp . were isolated from all 38 bighorn sheep and 16 of 17 domestic sheep included in this study . The isolates were characterized on the bases of species, biotype, serotype, biogroup, and restriction enzyme analyses (REA) as well as ribotyping of bacterial DNA . A P . haemolytica biotype 3, biogroup 11 isolate from a domestic sheep had biochemical, REA, and ribotype profiles which were identical to those of isolates from three bighorn sheep on the same range . None of the other isolates were found to be common to the two sheep species . Disease was not detected in any of the bighorn populations . However, bighorn sheep populations were extirpated on two ranges while increasing on the other two, including the range on which P . haemolytica biotype 3, biogroup 11 strain was isolated . Declining sheep numbers were not correlated with the presence of any one strain of Pasteurella spp from the sheep.

Toxicon, 1997 Jul, 35(7), 999 - 1010
Sir Charles James Martin MB FRS: Australian serpents and Indian plague, one-hundred years ago; Hawgood BJ; In 1891 as Demonstrator in Physiology at the University of Sydney, Charles Martin began the first systematic study of the chemical and physiological properties of the venoms of the Australian elapid species, Pseudechis porphyriacus and Notechis scutatus . Two major constituents were detected: a large coagulable protein which was associated with intravascular clotting, and a small proteinaceous molecule, an albumose, associated with neurotoxicity . Martin designed and constructed a high-pressure gelatin membrane ultrafilter for fractionation of venom . His studies indicated that certain physiological actions and clinical symptoms were related to the faster rate of diffusion within the tissue space of a neurotoxic constituent relative to a clotting constituent . Extending this work to toxin-antitoxin relationships, Martin provided evidence that antitoxin was a large molecule with slow diffusibility in tissue and advised the administration of curative serum (including diphtheria antitoxin) by intravenous injection . In 1903, Martin returned to London as Director of the Lister Institute of Preventive Medicine . He was soon involved in the planning of scientific work to be undertaken by the Commission for Investigation of Plague in India as the disease continued to ravage the subcontinent . Detailed epidemiological studies of possible factors involved in the spread of Pasteurella pestis showed, unequivocally, that infected rat fleas were the vector of transmission from rats to humans.

Can J Vet Res, 1997 Jul, 61(3), 187 - 92
Treatment of experimentally induced pneumonic pasteurellosis of young calves with tilmicosin; Morck DW et al.; Twenty four (24) healthy male Holstein calves (< 70 kg) were each experimentally infected by intrabronchial inoculation of 4.0 x 10(9) viable cells of Pasteurella haemolytica-AI (B122) at Time = 0 h . At 1 h following inoculation animals received either: 1) Sham treatment with sterile 0.85% saline SC (n = 12); or 2) a single injection of 10 mg tilmicosin per kg body weight (n = 12) . Calves that were non-infected and tilmicosin-treated were also included for determining tilmicosin concentrations in serum and lung tissue at 1, 2, 4, 6, 8, 24, 48, and 72 h (n = 3-per time) . In the infected calves, response to therapy was monitored clinically . Serum samples were collected for determination of tilmicosin concentrations using HPLC . Any animal becoming seriously ill was humanely killed . Complete necropsy examinations were performed on all animals and included gross pathologic changes, bacteriologic analysis, histopathology, and determination of pulmonary concentrations of tilmicosin . Tilmicosin treated animals responded significantly better to therapy than saline-treated control calves . Clinical assessment of calves during the study indicated that tilmicosin-treated calves had significantly improved by T = 8 h compared to satine-treated animals (P < 0.05) . At necropsy tilmicosin-treated calves had significantly less severe gross and histological lesions (P < 0.05) of the pulmonary tissue . Of the 12 saline-treated calves, 92% (11/12) had Pasteurella haemolytica-A1 in lung tissue, while of the tilmicosin-treated calves 0% (0/12) cultured positive for P . haemolytica . Mean (+/- standard error) serum tilmicosin concentrations in infected calves peaked at 1 h post-injection (1.10 +/- 0.06 micrograms/mL) and rapidly decreased to 0.20 +/- 0.03 microgram/mL, well below the MIC of 0.50 microgram/mL for P . haemolytica-A1 (B122), by 12 h . These serum concentrations were very similar to serum concentrations of tilmicosin in non-infected tilmicosin-treated calves . Lung tissue concentrations of the antibiotic were comparatively high, even at 72 h post-infection (6.50 +/- 0.75 ppm) . Lung tissue concentrations at 72 h were significantly higher in experimentally infected calves than in non-infected tilmicosin-treated animals (P < 0.05) . These data demonstrate that tilmicosin was effective in treating experimentally-induced pneumonic pasteurellosis as determined by alleviation of clinical signs, pathological findings at post mortem, and presence of viable bacteria from the lung . Concentrations substantially above MIC for P . haemolytica were present in lung tissue even at 72 h following a single subcutaneous injection of 10 mg tilmicosin per kg body weight.

J Med Microbiol, 1997 Jul, 46(7), 603 - 10
Identification by monoclonal antibodies of serotype D strains of Pasteurella multocida representing various geographic origins and host species; Vasfi Marandi M et al.; Two outer-membrane proteins (OMPs) of Pasteurella multocida serotype D, designated H and W, possess potentially important serotype D-specific antigens . Antigenicity as well as toxigenicity of 55 strains of P . multocida representing various serotypes, geographic origins and host species were studied by SDS-PAGE, enzyme-linked immunosorbent assay (ELISA), immunoblot and polymerase chain reaction (PCR) assays . Based on the electrophoretic mobility of protein H, different OMP patterns were observed within different capsular serotypes . Three monoclonal antibodies (MAbs) designated MT1, MT2 and MT3 were produced against H and W proteins of P . multocida in BALB/c mice . MAbs MT2 and MT3 reacted with two distinct epitopes on W protein of serotype D in competitive ELISA . MAb MT1 reacted with all serotype D-I strains but not with D-II strains, whereas MAb MT2 reacted with both serotype D-I and D-II strains in dot-ELISA and immunoblot assay . MAb MT3 reacted with all P . multocida strains belonging to different capsular serotypes in dot-ELISA . None of the MAbs reacted with other gram-negative bacteria tested, indicating that protein H has a serotype D-I specific epitope and protein W has both serotype and species-specific epitopes . PCR assay was used to identify toxigenic strains of P . multocida; 92% of P . multocida strains possess both toxA gene and MAb MT2 reacting epitope, suggesting a strong association between MAb MT2 reacting epitopes and toxA gene . Rapid dot-ELISA with MAb was found to be specific, sensitive and easy to perform and thus suitable for routine serotyping of P . multocida serotype D strains which might be potentially pathogenic.

Arch Otolaryngol Head Neck Surg, 1997 Jul, 123(7), 759 - 61
Pasteurella multocida epiglottitis; Wine N et al.; Pasteurella multocida, a small gram-negative coccobacillus, colonizes the nasopharynx and gastrointestinal tract of many animals, including cats and dogs . Most human infections with P multocida are due to animal bites, but the respiratory tract is the second most common site of infection . We describe the third case report (to out knowledge) of acute P multocida epiglottitis . The mode of transmission in this case was inhalation of infectious nasopharyngeal secretions from cats . The patient responded well to treatment with penicillin, the drug of choice for P multocida infections . Therefore, infection with P multocida, though rare, should be considered in the differential diagnosis in any case involving acute epiglottitis and exposure to cats.

Lab Anim, 1997 Jul, 31(3), 193 - 200
Microbiological monitoring of laboratory pigs; Hansen AK et al.; Purpose-bred minipigs, are often used as the non-rodent species in toxicology . Infections may interfere with animal experiments, and there are no scientific reasons why the non-rodent species should be of a lower microbiological quality than the rodent species . Therefore, a system for health monitoring of pigs was developed in order to raise the quality of laboratory pigs to the level of laboratory rodents . This system, which includes screening for several viruses, bacteria and ecto- and endoparasites, was used for monitoring minipigs from a barrier unit with the same standards applied to rodents units . In these pigs only rotaviruses are found, which was shown by both serological antibody detection and by detection of rotaviral antigen in faeces . In minipigs from another unit with far less hygienic protection rotaviruses were also found along with certain influenza- and coronaviruses, as well as Pasteurella spp . It is concluded, that it is possible to raise pigs of a microbiological quality comparable to the quality of rats and mice, and that advanced microbiological monitoring in pigs will reveal useful information.

Am J Vet Res, 1997 Jul, 58(7), 755 - 9
Intrastrain variation of lipopolysaccharide of Pasteurella multocida in turkeys; Coy SL et al.; OBJECTIVE: To document intrastrain variation of lipopolysaccharide (LPS) in Pasteurella multocida and correlate these changes with changes in determinants associated with virulence . ANIMALS: 25 broad-breasted white turkeys . PROCEDURE: Phenotypic bacterial variants were identified by lectin affinity and were assayed for adherence to epithelial cells and complement resistance in vitro . The LPS purified from these variants was subjected to polyacrylamide gel electrophoresis and lectin affinity analysis . Turkeys were challenge exposed, then observed for 1 week . At first sign of disease, or at the end of the study, turkeys were euthanatized, necropsied, and inspected for gross lesions . RESULTS: The LPS variant designated as Ricinus communis agglutinin-positive had greater adherence to epithelial cells, complement resistance, and virulence in turkeys than did the variant designated as R communis agglutinin-negative . CONCLUSIONS: Intrastrain variation of LPS exists in P multocida, and changes in LPS are correlated with changes in virulence.

Am J Vet Res, 1997 Jul, 58(7), 749 - 54
Growth of Pasteurella haemolytica and production of its leukotoxin in semi-defined media; Highlander SK; OBJECTIVE: To develop semi-defined media that support growth of the bovine pathogen, Pasteurella haemolytica, and use them to examine production of leukotoxin and an arginine-binding protein by this organism . SAMPLE POPULATION: 10 P haemolytica A1 strains and 1 P multocida strain . PROCEDURE: Bacterial strains were cultivated at 37 C in media containing various amino acids, carbon sources, vitamins, and cofactors, and absorbance (OD600) was measured . Leukotoxin and arginine-binding protein production were assessed by immunoblot analysis . RESULTS: Optimal growth required supplementation with 0.1% fetal bovine serum, gelatin, or purified bovine serum albumin . Calcium pantothenate and thiamine were essential for growth, and a variety of carbon sources could be utilized . In the complete medium, 15 amino acids were included; however, in the minimal medium, no amino acids were required . All strains (except P multocida) grew in the complete medium and 7 grew well in the minimal medium . Leukotoxin was not produced when amino acids were limiting, but could be enhanced by addition of 0.2% NH4SO4 . Production of the arginine-binding protein was not affected by nitrogen availability or by presence of L-arginine . CONCLUSIONS: Two media that support good growth of P haemolytica strains were developed . The minimal medium is simple to prepare and manipulate and its use revealed a potential role of nitrogen availability in the regulation of leukotoxin expression . CLINICAL RELEVANCE: Creation of these media will permit continued studies of the response of P haemolytica to environmental conditions that may mimic those encountered in the bovine respiratory tract during shipping.

Mol Microbiol, 1997 Jun, 24(5), 1061 - 70
Molecular localization of the Escherichia coli cytotoxic necrotizing factor CNF1 cell-binding and catalytic domains; Lemichez E et al.; Cytotoxic necrotizing factor type 1 (CNF1) induces, in epithelial cells, the development of stress fibres via the GTPase Rho pathway . We showed that CNF1 is able to modify Rho both in vitro and in vivo . Recombinant N-terminal 33kDa (CNF1Nter) and C-terminal 14.8-31.5 kDa (CNF1Cter) regions of the CNF1 protein allowed us to demonstrate that the N-terminal region contains the cell-binding domain of the toxin and that the C-terminal region is responsible for its catalytic activity . CNF1Nter lowered the activity of CNF1 when provided to cells before the toxin whereas CNF1Cter had no effect on CNF1 cell toxicity . CNF1Cter was sufficient to induce a typical CNF1 phenotype when microinjected into African green monkey kidney cells (Vero cells), and was able to modify Rho as previously reported for CNF1 . The C-terminal domain lost its catalytic activity when deleted of various subdomains, suggesting a scattered distribution of catalytic-site amino acids . Elucidation of the CNF1 functional organization and analysis of amino acid homologies between CNFs (CNF1, CNF2), Pasteurella multocida toxin (PMT) and dermonecrotic toxin of Bordetella pertussis (DNT) allowed us to postulate that CNFs and DNT act on Rho via the same enzymatic activity located in their C-terminus, and that CNFs and PMT probably bind to analogous cell receptors.

Pediatr Nephrol, 1997 Jun, 11(3), 353 - 4
Pasteurella multocida peritonitis in patients undergoing peritoneal dialysis; Loghman-Adham M; A 12-year-old girl on peritoneal dialysis developed sub-clinical peritonitis due to Pasteurella multocida, following puncture of her dialysis tubing by a domestic cat . Only four other similar cases of P . multocida peritonitis have been reported in adults . This unusual form of peritonitis could be easily prevented by not allowing domestic animals to come into contact with dialysis tubings in patients undergoing peritoneal dialysis.

FEMS Microbiol Lett, 1997 May 15, 150(2), 197 - 202
Divergent activity and function of superoxide dismutases in Pasteurella haemolytica serotypes A1 and A2 and Pasteurella trehalosi serotype T10; Rowe HA et al.; Representative strains of Pasteurella haemolytica serotypes A1 and A2 and Pasteurella trehalosi serotype T10 were examined for the presence of superoxide dismutase . Visualisation of superoxide dismutase enzyme activity on polyacrylamide gels, and specific inhibition with potassium cyanide verified a copper/zinc (Cu/Zn) superoxide dismutase only in serotype A2 whereas serotypes A1 and T10 showed other superoxide dismutase activity . Using a simple freeze-thaw method the cellular location of superoxide dismutase enzyme activity was determined in all three serotypes . In serotypes A1 and A2 but not T10 superoxide dismutases were located in the periplasm . The viability of serotypes A2 and T10 cells in the presence of exogenous superoxide was unchanged over a 30 min period, whereas serotype A1 cells declined in viability between 15 and 30 min . Purified immunoglobulin from sheep convalescent serum did not reduce superoxide dismutase activity in the serotypes in an in vitro assay . The presence of this enzyme within the pasteurellae suggests a supportive role in the virulence of this major pathogen of ruminants.

J Infect, 1997 May, 34(3), 263 - 4
Pasteurella multocida infection of a total hip arthroplasty following cat scratch; Takwale VJ et al.; Pasteurella multocida is a well recognized cause of sepsis following animal contact particularly bites and scratches . Spread to prosthetic joints may occur particularly in immunocompromised patients . Immunocompromised patients with prosthetic joints should be warned that animals are potential sources of serious infection and urgent medical advice should be sought if bitten or scratched.

Zentralbl Veterinarmed A, 1997 May, 44(3), 179 - 87
Efficacy of the combination sodium ceftiofur-flumethasone in the treatment of experimental Pasteurella haemolytica bronchopneumonia in calves; Sustronck B et al.; Severe acute bronchopneumonia was induced in 18 conventional Friesian-Holstein calves by inoculating them intratracheally with Pasteurella haemolytica type A1 . Six of the calves received no treatment and served as controls . Six of the calves were treated with sodium ceftiofur and six were treated with sodium ceftiofur and flumethasone . The mortality rate in the group of calves treated with sodium ceftiofur and flumethasone was significantly lower and their clinical and haematological parameters returned to normal significantly faster than in the control calves and the calves treated with sodium ceftiofur alone.

J Biochem (Tokyo), 1997 May, 121(5), 902 - 13
Two genes encoding serine protease homologues in Serratia marcescens and characterization of their products in Escherichia coli; Ohnishi Y et al.; A serine protease (SSP) of Serratia marcescens is one of the extracellular enzymes secreted from this Gram-negative bacterium . SSP is produced as a large precursor and converted to a mature protein by cleavages removing an NH2-terminal signal sequence and a COOH-terminal pro-region . This COOH-terminal pro-region is integrated into the outer membrane and has a functional role for the export of the mature protein across the outer membrane . Southern hybridization analysis with a DNA fragment encoding the COOH-terminal pro-region as the probe showed a wide distribution of nucleotide sequences encoding SSP exporter-like proteins among Serratia species . Moreover, S . marcescens IFO 3046, from which the ssp gene had been cloned, was found to contain two ssp homologues (ssp-h1 and ssp-h2) . They were cloned and their nucleotide sequences were determined . The two ssp homologues were found to exist in tandem on the genome and their amino acid sequences showed 81% identity to each other . Both of them showed 55% identity in amino acid sequence to preproSSP . In addition, both showed end-to-end similarity to the 100 kDa serotype-specific antigen (Ssa1) of Pasteurella haemolytica . Escherichia coli JM105 containing ssp-h1 gene produced a 53 kDa protein corresponding to the NH2-terminal portion and a 49 kDa protein corresponding to the COOH-terminal portion, both of which were rigidly integrated in the outer membrane . Consistent with the significant similarity of the COOH-terminal portions of the homologues to that of SSP, they showed the ability to translocate the mature SSP part across the outer membrane into the medium . Furthermore, the NH2-terminal portion of the homologue was not translocated into the outer membrane without its COOH-terminal part . All of these data show that the SSP homologues are outer membrane proteins that are translocated into the outer membrane with the aid of the translocator function of their COOH-terminal part.

J Comp Pathol, 1997 May, 116(4), 415 - 8
Pulmonary venous thrombosis in caprine Pasteurella pneumonia; Scholes SF et al.; A 3-year-old Angora goat that developed acute fibrinous pleuropneumonia associated with Pasteurella haemolytica infection had thrombotic occlusion of a large pulmonary vein . Thrombosis of pulmonary capillaries occurs in pneumonic pasteurellosis, but large vessels are not commonly affected . This unusual lesion may reflect the procoagulant effect of pasteurella endotoxin on vascular endothelium . An incidental observation was the presence of myocardial-type muscle fibres in the tunica media of the pulmonary vein.

Antimicrob Agents Chemother, 1997 May, 41(5), 1193 - 5
Comparative in vitro activities of DU-6859a, levofloxacin, ofloxacin, sparfloxacin, and ciprofloxacin against 387 aerobic and anaerobic bite wound isolates; Goldstein EJ et al.; The activities of DU-6859a, levofloxacin, ofloxacin, sparfloxacin, and ciprofloxacin against bite wound isolates were determined by the agar dilution method . DU-6859a was the most active compound (MICs, < or = 0.125 microg/ml) against all Pasteurella species, Staphylococcus aureus, and streptococci; anaerobes were susceptible to < or = 0.5 microg/ml, except fusobacteria, which were susceptible to < or = 2 microg/ml . Against aerobes, levofloxacin was more active than ofloxacin (MIC at which 90% of isolates are inhibited {MIC90}, < or = 1.0 microg/ml for both) and sparfloxacin and ciprofloxacin were also active (MIC90s, < or = 0.25 and < 1 microg/ml, respectively).

Clin Infect Dis, 1997 May, 24(5), 1004 - 6
Use of random amplification of polymorphic DNA in a case of Pasteurella multocida meningitis that occurred following a cat scratch on the head; Schuur PM et al.; We cultured Pasteurella multocida from the cerebrospinal fluid (CSF) of a 4-month-old infant who presented with meningitis . The patient had been scratched on the head by a cat . Culture of the cat's claws also yielded P . multocida . The isolates had identical biochemical patterns . Analysis of both strains by random amplification of polymorphic DNA and comparison of these strains with P . multocida strains isolated from other cats showed that the two strains were identical and completely different from the unrelated isolates . Our patient's meningitis most likely resulted from direct inoculation of P . multocida into the CSF.

J Med Chem, 1997 Apr 25, 40(9), 1340 - 6
Quantitative structure-activity relationships among macrolide antibacterial agents: in vitro and in vivo potency against Pasteurella multocida; McFarland JW et al.; Quantitative structure-activity relationships have been found among macrolide antibacterial agents in their potencies against the bacterial pathogen Pasteurella multocida both in vitro and in mouse infections . To obtain these relationships we measured, among other things, the pK(a)'s and log P's of 15 known macrolides of diverse structures . Among these compounds, in vitro potency {log(1/MIC)} is a function of log P, log D, and CMR (R = 0.86) . In vivo potency is a function of the higher pK(a), the HPLC chromatographic capacity factor log k', log(1/MIC) and pNF (R = 0.93) . pNF is defined as the negative logarithm of the fraction of neutral drug molecules present in aqueous solution at pH 7.4 . The same physical properties were determined for 14 macrolides not used in developing the original QSAR models . Using the in vivo model, we calculated the mouse protection potency ranges for these new compounds . Ten estimates agreed with those observed, three were lower by a half-order of magnitude, and one was calculated to be active in the range of 15-50 mg/kg, but in fact was not active at 50 mg/kg, the highest level tested . When these new compounds were combined with the original 15, and the QSAR's updated, the new equations for the in vitro and in vivo potencies were essentially the same as those originally found . Hence, the physical properties indicated above are major determinants of macrolide antibacterial potencies.

Vet Microbiol, 1997 Apr, 55(1-4), 241 - 6
Effect of porcine reproductive and respiratory syndrome virus on subsequent Pasteurella multocida challenge in pigs; Carvalho LF et al.; This trial was conducted to evaluate the effect of Porcine reproductive and respiratory syndrome virus (PRRSv) on a subsequent challenge with Pasteurella multocida in pigs . Sixteen, 3-4 week-old piglets, from a PRRSv and Aujeszky disease virus (ADV) free herd were used . Animals were equally and randomly allocated in four groups which were treated according the following schedule: Group I: negative controls; Group II: inoculation with only PRRSV; Group III: inoculation with PRRSV and P . multocida; Group IV: inoculation with ADV and P . multocida (positive controls) . PRRSV and ADV were inoculated intranasally, at the doses of 10(4.6) and 10(4.5) TCID50/ml, respectively . Five days later, pigs from groups III and IV were inoculated intranasally, with two ml of a 10(9) CFU/ml suspension of equal parts of P . multocida, strains A52 and A24 . No lesions were observed in piglets of group I . Microscopically, interstitial pneumonia was identified in all piglets of groups II and III and 3/4 piglets from group IV . Bronchopneumonia was detected in 3/4 of the piglets from group III and in all animals of group IV which, additionally, showed meningo-encephalitis and purulent rhinitis . Macroscopically, only piglets of groups III and IV had lung consolidation . However, much lower pneumonic scores (2.3%) were observed in group III, where 3 of 4 piglets were affected . On the other hand, all piglets of group IV showed some degree of pulmonary consolidation, with a mean score of 13.7% . Based on these results, it appears that the role of PRRSV as a initiator of secondary diseases is still undefined, but is probably mild . There was no clear interaction between PRRSv and Pasteurella multocida under the conditions and strains tested here.

Avian Dis, 1997 Apr-Jun, 41(2), 317 - 25
Comparison of live avirulent PM-1 and CU fowl cholera vaccines in turkeys; Hopkins BA et al.; The live avirulent PM-1 Pasteurella multocida vaccine, grown in brain-heart infusion broth, was evaluated and compared in two experiments with the Clemson University (CU) vaccine, which had been shown to be effective in preventing fowl cholera in turkeys . Experiment 1 was performed during warm environmental temperatures and Expt . 2 during cooler environmental temperatures . The PM-1 vaccine was comparable with the CU vaccine in protecting turkeys against challenge with virulent P . multocida but was considered no less virulent than the CU because turkeys died after vaccination with both the PM-1 and the CU vaccines . A significantly (P < 0.05) higher percentage of unvaccinated turkeys challenged during the cooler environmental temperatures died than did unvaccinated turkeys challenged during the warmer temperatures . A microtiter agglutination test demonstrated a significant (P < 0.01) correlation between the level of serum anti-P . multocida antibody found 1 wk after vaccination and survival after challenge with virulent P . multocida in Expt . 1 and a significant (P < 0.05) correlation between these parameters in Expt . 2 . However, there was a significant (P < 0.01) negative correlation between serum anti-P . multocida antibody titer 1 wk after vaccination and body weight gained 4 wk after vaccination, but before challenge, in Expt . 1, suggesting that vaccination with the live vaccines may have had a negative effect on body weight gain . At 4 wk after challenge or 8 wk after vaccination in Expt . 2, there was also a highly significant (P < 0.001) negative correlation between these parameters in the surviving turkeys.

Berl Munch Tierarztl Wochenschr, 1997 Apr, 110(4), 139 - 42
{Detection of dermonecrotic toxin genes in Pasteurella multocida strains using the polymerase chain reaction (PCR)}; Hotzel H et al.; A PCR method was developed which allows to distinguish between Pasteurella multocida strains carrying or lacking the dermonecrotic toxin gene . Specific primers were used to amplify a 1501-bp DNA fragment from the genomic dermonecrotic toxin gene region . Isolated DNA, broth cultures and swabs were used as samples . Detection of the toxin gene directly from swab samples accelerates considerably the diagnosis since cultivation steps can be omitted . The results of PCR corresponded to findings obtained by ELISA.

J Trace Elem Med Biol, 1997 Apr, 11(1), 28 - 31
Udder orf infection and its role in ovine clinical mastitis caused by Pasteurella haemolytica; Burriel AR; During an experimental study of ovine subclinical mastitis caused by coagulase-negative staphylococci, an outbreak of contagious ecthyma occurred among ewes unvaccinated against parapox virus . The same group of ewes developed a high rate (43.7%) of clinical mastitis caused by Pasteurella haemolytica . The rate of clinical mastitis among ewes vaccinated against parapox virus was very low (3.7%) suggesting that the presence of orf in the unvaccinated ewes was contributing to the high rate of clinical mastitis . An examination of the iron, sodium, potassium and albumin concentration of milk collected from 16 unvaccinated and nine randomly selected vaccinated ewes before experimental infection with coagulase-negative staphylococci or their uninfected control mammary glands indicated significant differences in the iron (p < 0.0001) and sodium (p = 0.01) concentration . Increased iron concentration in the milk may have assisted in the development of udder infection caused by P . haemolytica as iron is easily utilised by this bacterium.

Zentralbl Veterinarmed B, 1997 Apr, 44(2), 99 - 104
Bacteria associated with enzootic pneumonia in goats; Oros J et al.; A histological and microbiological study of lung samples from 83 slaughtered goats (33 kids and 50 adults) drawn from a flock with a history of pleuropneumonia caused by mycoplasmas of the M . mycoides group was carried out . A total of 82% (27/33) of kids and 36% (18/50) of adult goats presented pulmonary lesions characteristic of enzootic pneumonia: lesions took the form of bronchointerstitial pneumonia with peribronchial and peribronchiolar proliferation of lymphocytes . Microbiological analysis confirmed a range of mycoplasma species, including Mycoplasma mycoides ssp . mycoides Large Colony (MmmlC) (3.70%; 1/27), Mycoplasma mycoides ssp . capri (Mmc) (7.40%; 2/27), Mycoplasma putrefaciens (22.2%; 6/27), Mycoplasma arginini (3.70%; 1/27) and Mycoplasma sp . (7.40%; 2/ 27), as well as Pasteurella multocida (14.8%; 4/27), associated with enzootic pneumonia lesions in younger animals, whereas Mycoplasma sp . was associated with enzootic pneumonia in adult goats (22.0%; 4/18) . Cilia-associated respiratory (CAR) bacillus found by histochemical examination was associated with enzootic pneumonia in kids (25.9%; 7/27) and goats (44.4%; 8/18), being the first description of this bacterium in adult goats.

Zentralbl Bakteriol, 1997 Apr, 285(4), 459 - 79
Relationships among strains classified with the ruminant Pasteurella haemolytica-complex using quantitative evaluation of phenotypic data; Angen O et al.; The phenotypic relationships among 246 trehalose-negative strains classified under the {Pasteurella} haemolytica-complex in ruminants were investigated by clustering and multidimensional ordinations based upon 79 phenotypic characters . A quantitative evaluation of phenotypic data using a 5-level scoring system is presented permitting a comprehensive utilization of the recorded phenotypic variation among the strains in the analyses . Clustering and ordination analyses display complementary aspects of data which has been clearly demonstrated in this investigation . The main clusters revealed by the numerical techniques could be related to distinctive phenotypic differences and showed an extensive correlation with the recognized biogroups . This classification was based only upon 4 characters (fermentation of L-arabinose, D-sorbitol, glucosides and ornithine decarboxylase) . In contrast, there was no obvious interpretation of the clusters formed by using binary scores . Phenotypic subgroups within the recognized biogroups have been described as well as a new, related group of bacteria, tentatively named Bisgaard taxon 36 . Quantitative interpretation of phenotypic data seems to represent a promising method for finding relations among affiliated strains of bacteria and to assist in forming hypotheses for subsequent genotypic investigations.

J Wildl Dis, 1997 Apr, 33(2), 332 - 5
Pasteurella multocida serotype 1 isolated from a lesser snow goose: evidence of a carrier state; Samuel MD et al.; Pharyngeal swabs were collected from 298 lesser snow geese (Chen caerulescens caerulescens) at Banks Island (Northwest Territories . Canada) in the summer of 1994 . Pasteurella multocida serotype 1 was isolated from an adult male bird and P . multocida serotype 3 was isolated from an adult female goose . Pathogenicity of the serotype 1 isolate was confirmed by inoculation in Pekin ducks (Anas platyrhynchos) . The serotype 3 isolate was non-pathogenic in Pekin ducks . This is the first documented isolation of pathogenic P . multocida serotype 1 from apparently healthy wild snow geese.

J Med Microbiol, 1997 Apr, 46(4), 276 - 84
Characterisation of the leukotoxin produced by different strains of Pasteurella haemolytica; Saadati M et al.; Pasteurella haemolytica isolates from cattle and sheep, including representatives of different serotypes and untypable strains, were examined for leukotoxin (Lkt) production at the end of the log phase of growth in brain heart infusion broth . There were marked differences in leukotoxic activity in culture supernate samples, as measured by chemiluminescence-inhibition assays with bovine and ovine neutrophils, even between strains of the same serotype . There was also some variation in the amount and mol . wt of the Lkt protein produced by different strains, as judged by SDS-PAGE, immunoblotting and ELISA . Some strains produced normal amounts of Lkt protein which had only low leukotoxic activity . Most strains produced Lkt of 105 kDa whereas four strains produced a higher mol . wt form of c . 108 kDa, including two of the five serotype A2 strains examined . Thus, the P . haemolytica isolates showed considerable heterogeneity in terms of leukotoxin production, mol . wt and activity, even within a given serotype.

J Anim Sci, 1997 Apr, 75(4), 1112 - 8
Effects of copper deficiency and copper deficiency coupled with high dietary iron or molybdenum on phagocytic cell function and response of calves to a respiratory disease challenge; Gengelbach GP et al.; A study was conducted to determine the effects of supplementing a diet marginally deficient in copper (Cu) with iron (Fe), molybdenum (Mo), or Cu on phagocytic cell function and disease resistance of calves . Thirty-one calves were born to heifers fed a corn silage-based diet containing 4.5 mg of Cu/kg . Treatments consisted of 1) control (CON; no supplemental Cu, Fe, or Mo), 2) 600 mg of Fe added/kg (FE), 3) 5 mg of Mo added/kg (MO), or 4) 10 mg of Cu added/kg of DM (CU) . Activity of superoxide dismutase was lower (P < .06) in neutrophils from MO vs CON or CU calves at 170 d of age . bactericidal activity of neutrophils from MO calves tended (P = .15) to be lower compared with those from CU calves at 70 d of age . Calves were inoculated intranasally with live infectious bovine rhinotracheitis virus (IBRV) 2 d after weaning, followed by intratracheal administration of Pasteurella hemolytica 5 d later . Iron- and Cu-supplemented calves exhibited higher (P < .01) body temperatures and lower (P < .06) feed intakes following IBRV inoculation compared with CON and MO calves . Copper-supplemented calves had higher levels of plasma tumor necrosis factor (TNF) than MO calves at weaning (P < .05) and tended to have higher plasma TNF (P = .11) than FE and MO calves 5 d after IBRV inoculation . These data indicate that dietary levels of Mo and Cu can affect body temperature and feed intake responses to disease by affecting TNF and perhaps other cytokines.

Int J Syst Bacteriol, 1997 Apr, 47(2), 575 - 6
Characterization of leptospiral serovars by randomly amplified polymorphic DNA fingerprinting; Ramadass P et al.; Randomly amplified polymorphic DNA (RAPD) fingerprinting of 14 laboratory strains of leptospiral serovars (serovars australis, autumnalis, ballum, bataviae, canicola, grippotyphosa, hardjoprajitno, hebdomadis, icterohaemorrhagiae, javanica, pomona, pyrogenes, panama, and tarassovi) was carried out by using a pair of primers . Each serovar had a unique and distinct fingerprint pattern . DNAs of other bacterial species, including Escherichia coli, Pasteurella multocida, Salmonella spp., Pseudomonas spp., and Klebsiella spp., did not show any amplification . RAPD fingerprinting was found to be a rapid and sensitive method for serovar identification when it was compared to DNA restriction enzyme analysis, which produced a larger number of bands that made it more difficult to compare serovars.

Curr Microbiol, 1997 Apr, 34(4), 244 - 9
Serotyping and enzyme characterization of Pasteurella haemolytica and Pasteurella multocida isolates recovered from pneumonic lungs of stressed feeder calves; Purdy CW et al.; Ninety-one isolates of Pasteurella multocida (Pm)and 124 of Pasteurella haemolytica (Ph) were recovered from the lungs of calves that died of bovine respiratory tract disease (BRTD) . Nine Pm enzyme profiles (A through I) and 9 Ph enzyme profiles (J through R) were determined for the Pasteurella isolates . The Pm isolates were relatively evenly divided among the enzyme profiles, with one exception, profile I . The Ph isolates were not evenly distributed among the profiles . Fifty of the 91 Pm isolates were serotyped . Forty-two Pm isolates were positive for capsule type A, and 8 were untypable . Five somatic type antigen profiles (3; 3,4; 3,7; 3,4,7; and 4) were identified among the 50 serotyped Pm isolates; one isolate was untypable . The Ph isolates were further divided through serotyping and grouped as follows: 74 (60%) Pasteurella haemolytica A1 (PhA1), 12 (10%) PhA2, 4 (3%) PhA5, and 34(27%) PhA6 . Eighty-one percent of the Ph serotypes were clustered in the M and N enzyme profile . The P enzyme profile was almost unique to PhA2 (8 of 12, 67% of PhA2 isolates) . Results of this study indicate a need to collect more data on Ph serotypes at the state veterinary diagnostic laboratories.

J Med Chem, 1997 Mar 14, 40(6), 1041 - 5
Repromicin derivatives with potent antibacterial activity against Pasteurella multocida; McFarland JW et al.; Reductive amination of repromicin with polyfunctional amines has led to new macrolide antibacterial agents, some of which are highly potent against the Gram-negative pathogen Pasteurella multocida both in vitro and in a mouse infection model . A key element in this discovery was the recognition that among certain known macrolides increasing lipophilicity results in diminished in vivo activity . One repromicin derivative, 20-{N-{3-(dimethylamino)-propyl}-N-L-alanylamino}-20-deoxorepro micin (35), was selected for advanced evaluation . At 5 mg/kg, a single subcutaneous dose was found to control induced pasteurellosis in swine and induced respiratory disease in cattle.

Vet Microbiol, 1997 Mar, 54(3-4), 369 - 74
RSF1010-based shuttle vectors for cloning and expression in Pasteurella multocida; Lee MD et al.; The broad host-range cloning vectors, pJRD215 and pMMB67EH, were evaluated for stability and cloning efficiency in Pasteurella multocida . Transformation of P . multocida by electroporation was unreliable and poorly efficient regardless of whether the transforming DNA was isolated from E . coli or P . multocida . Both vectors contain a mob site that enabled transfer by conjugation from E . coli to P . multocida with high efficiency . Kanamycin, streptomycin, and ampicillin resistance encoded by the vectors were expressed in P . multocida . LacZ was cloned in pMMB67EH, an expression vector, and was transferred to P . multocida by conjugation . The transconjugants expressed a functional beta-galactosidase as determined by o-nitrophenyl-beta-D-galactopyranoside (ONPG) test . We propose the use of these cosmid and expression vectors as a shuttle vectors for cloning in P . multocida.

Vet Microbiol, 1997 Mar, 54(3-4), 343 - 55
Pasteurella multocida enters polarized epithelial cells by interacting with host F-actin; Rabier MJ et al.; We investigated the interaction of an avian strain of Pasteurella multocida with the cytoskeleton of MDCK cells, which formed a polarized epithelium when grown on type I collagen coated filters . Bacteria were incubated with MDCK cells for 30 min . 2, 4 and 6 hours and their location and association with the cell cytoskeleton determined by double-label immunofluorescence confocal microscopy . Cells were stained with a polyclonal antiserum to the outer-membrane proteins of P . multocida and with rhodamine phalloidin which specifically binds filamentous (F) actin . Confocal microscopy revealed that bacteria entered the cells by 30 min, and that by 6 hours there was a marked alteration in the actin cytoskeleton in which long filaments were reorganized to discrete foci of short actin filaments, within which were one or more bacteria . Electron microscopy demonstrated that by 2 hours, each bacterium was associated with many short 5-6 nm filaments . Treatment of MDCK cells with cytochalasin D for either 30 minutes or 24 hours prior to infection disrupted the actin cytoskeleton and inhibited entry of P . multocida.

Semin Respir Infect, 1997 Mar, 12(1), 54 - 6
Pasteurella multocida pneumonia; Klein NC et al.; Pasteurella multocida, a gram-negative coccobacillus which colonizes the nasopharynx and gastrointestinal tract of many animals, is a well known cause of soft tissue infection after animal bites . Human infection can also occur after non-bite animal exposure, usually via inhalation of contaminated secretions . The respiratory tract is the second most common site of Pasteurella infection after soft tissue infection . Most patients with Pasteurella pulmonary infection are elderly with underlying lung disease, either COPD, bronchiectasis, or malignancy . The spectrum of disease includes pneumonia, tracheobronchitis, lung abscess, and empyema . Clinical features of Pasteurella respiratory tract infections are indistinguishable from other pathogens . A history of cat or dog exposure should alert the clinician to consider Pasteurella as a potential pulmonary pathogen in an elderly patient with chronic lung disease . The preferred drug for the treatment of Pasteurella infections is penicillin . Alternately, doxycycline is highly effective against P multocida.

Appl Environ Microbiol, 1997 Mar, 63(3), 924 - 30
Nitrate-reducing bacteria on rat tongues; Li H et al.; Nitrite-producing bacteria (NPB) were isolated from tongues of laboratory rats . The most commonly found nitrite-producing organism was Staphylococcus sciuri, followed by Staphylococcus intermedius, Pasteurella spp., and finally Streptococcus spp . Both morphometric quantification of bacteria on tongue sections and enumeration of culturable bacteria (CFU) showed an increase in the density of bacteria towards the posterior tongue . Up to 65% of bacteria were located in the deep clefts on the posterior tongue . The proportion of culturable NPB in the total culturable microbial population increased from 6% (10(5) CFU cm-2) on the anterior tongue to 65% (10(7) CFU cm-2) on the posterior tongue . Different species compositions of NPB were found on different tongue sections with S . intermedius populations decreasing and S . sciuri and Pasteurella populations increasing towards the posterior tongue . Nitrite production was sensitive to oxygen, and significant nitrite production was only detected on the posterior tongue where the majority of bacteria are situated in deep clefts in the tongue surface . This study suggests the importance of bacteria in nitrite production, from nitrate, on the tongue . Nitrite produced on the tongue may subsequently form nitric oxide in the acidic environment of the stomach . Because of the antimicrobial properties of nitric oxide, a key role for nitrate-reducing tongue bacteria in host animal defense against food-borne pathogens in proposed.

Infect Immun, 1997 Mar, 65(3), 957 - 63
Increase of glycocalyx and altered lectin agglutination profiles of Pasteurella haemolytica A1 after incubation in bovine subcutaneous tissue chambers in vivo or in ruminant serum in vitro; Brogden K et al.; Pasteurella haemolytica serotype A1 (bovine strain OK) was incubated for 2 and 6 h in bovine subcutaneous tissue chambers in vivo, and ovine strain 82-25 and bovine strain L011 were incubated in vitro for 2 h in heat-inactivated ovine or bovine serum from which gamma globulin had been depleted by protein G affinity chromatography to assess changes in morphology and lectin agglutination profiles (strains 82-25 and L101 only) . Cells, removed from chambers after 2 h, were covered with an extensive, dense glycocalyx extending approximately 0.5 microm from the cell surface . In many cells, the glycocalyx was separated from the cell surface by a clear, electron-transparent area . Cells, removed at 6 h, were covered with a sparse glycocalyx of fine fibers 0.2 to 0.3 microm from the cell surface . Strains 82-25 and L101, incubated for 2 h in heat-inactivated ovine or bovine serum or in heat-inactivated ovine or bovine serum depleted of gamma globulin by protein G affinity chromatography, were also covered with a glycocalyx . The glycocalyx did not bind protein A-colloidal gold and therefore did not contain aggregates of accumulated antibody . Strains 82-25 and L101 were incubated individually for 2 h in 10 mM sodium phosphate buffer (pH 7.2) containing 0.14 M NaCl, 0.5 mM CaCl2, and 0.15 mM MgCl2 or with this buffer and either 25% heat-inactivated, gamma globulin-depleted ovine serum or 25% heat-inactivated, gamma globulin-depleted bovine serum . Agglutination profiles were then determined with 17 lectins in 10 mM HEPES-buffered saline (pH 8.4) with 0.1 mM CaCl2 and 0.08% sodium azide . Profiles did not vary with 10 of 17 lectins . However, profiles did vary with peanut agglutinin, Phaseolus vulgaris leucoagglutinin, Sophora japonica agglutinin, Maackia amurensis lectin II, Narcissus pseudonarcissus (daffodil) lectin, Griffonia simplicifolia lectin I, and Pisum sativum agglutinin . Altered profiles indicate a change in the bacterial cell surface, possibly by adsorption or alteration of surface carbohydrate moieties by serum constituents.

Gene, 1997 Feb 28, 186(2), 207 - 11
Plasmids for heterologous expression in Pasteurella haemolytica; Fedorova ND et al.; New cloning and expression vectors that replicate both in Pasteurella haemolytica and in Escherichia coli were constructed based on a native sulfonamide (SuR) and streptomycin (SmR) resistant plasmid of P . haemolytica called pYFC1 . Each shuttle vector includes an MCS and a selectable antibiotic resistance marker that is expressed in both organisms . Plasmid pNF2176 carries the P . haemolytica ROB-1 beta-lactamase gene (blaP, ApR) and pNF2214 carries the Tn903 aph3 kanamycin resistance (KmR) element . The expression vector, pNF2176, was created by placing the MCS downstream of the sulfonamide gene promoter (PsulII) on pYFC1; this was used to clone and express the promoterless Tn9 chloramphenicol resistance gene (cat, CmR) in P . haemolytica (pNF2200) . A promoter-probe vector (pNF2283) was constructed from pNF2200 by deleting PsulII.

Zentralbl Bakteriol, 1997 Feb, 285(3), 440 - 4
Pasteurella caballi infection following a horse bite; Escande F et al.; The isolation of Pasteurella caballi from an horse-bite wound in a 56-year-old man is reported . Biochemical characteristics are described and compared with the other species representing the genus Pasteurella . This strain probably represents the first human isolate of P . caballi in France.

Vaccine, 1997 Feb, 15(2), 203 - 8
Cross protective immunity conferred by a marker-free aroA mutant of Pasteurella multocida; Homchampa P et al.; The aroA gene from Pasteurella multocida serotype A:1 (X-73) was cloned by complementation of the Escherichia coli aroA mutant AB2829 with a DNA library constructed in pUC18 . The cloned aroA gene was inactivated by deletion of a 300 bp internal sequence and reintroduced by homologous recombination into the chromosome of X-73 and P-1059 (serotype A:3) using a Pasteurella-E . coli shuttle vector pPBA1100 . By subjecting the transformed cells to repeated subculturing in the presence of antibiotic selection coupled with auxotrophic enrichment, marker-free aroA mutants of X-73 and of P-1059 were isolated and designated PMP1 and PMP3, respectively . PMP1 and PMP3 were highly attenuated and capable of conferring complete protection against subsequent lethal challenge infection in a mouse model . Moreover, PMP3-immunized mice were protected against heterologous challenge infection with serotype A:1 or A:4.

J Small Anim Pract, 1997 Feb, 38(2), 51 - 6
New combination for the therapy of canine otitis externa . I . Microbiology of otitis externa; Kiss G et al.; In order to compound a new drug combination against canine otitis externa (OE), 515 dogs affected with OE were subjected to physical examination and microbiological analysis of their ear exudates . OE was erythematous-ceruminous in 83 per cent and suppurative in 17 per cent of the patient material . Erythematous-ceruminous inflammations were characterised by severe pruritus and accumulation of brownish, greasy cerumen in the auditory canal . The yeast Malassezia pachydermatis was isolated from the ears of 76 per cent of the dogs, often in combination with Staphylococcus intermedius bacteria . M pachydermatis showed the most sensitivity, in decreasing order of efficacy, to ketoconazole, econazole, clotrimazole, miconazole and nystatin . S intermedius isolates were most sensitive to amoxycillin-clavulanic acid, enrofloxacin, cephalexin and gentamicin . The microorganism most frequently isolated from dogs with suppurative OE was Pseudomonas aeruginosa; in some cases Proteus, Streptococcus and Pasteurella were also isolated . The P aeruginosa isolates showed the highest sensitivity to gentamicin, polymyxin B and tobramycin.

Vet Microbiol, 1997 Feb, 54(2), 167 - 83
Outer membrane proteins of bovine Pasteurella multocida serogroup A isolates; Dabo SM et al.; The outer membrane proteins (OMPs) of P . multocida serotypes A3 (7 isolates), A4 (2 isolates), A3,4 and A2 (one isolate each) obtained from pneumonic cattle (10 isolates) and from one pig isolate were investigated to identify potential immunogens . SDS-PAGE of P . multocida OM isolated by SDG centrifugation of spheroplasts revealed eight major OMPs . Outer membranes isolated by sarcosyl extraction or SDG had similar protein composition on Coomassie blue-stained SDS-PA gel and on immunoblots . Two major OMPs (M(r)s of 35 and 46 kDa at 100 degrees C) demonstrated heat modifiability with apparent M(r)s of 30 and 34 kDa at 37 degrees C, respectively . The N-terminal aa sequences of these heat modifiable proteins revealed homology with E . coli OmpA and Hib P1 proteins, respectively . Protease treatment of whole cells followed by western immunoblots using bovine convalescent sera identified several immunogenic, surface-exposed and conserved OMPs among the eleven P . multocida isolates examined . The whole organism SDS-PAGE profiles of the eleven P . multocida isolates differed such that six patterns were seen . These patterns could potentially be used as a typing system for P . multocida bovine isolates based on the molecular weights of whole cell proteins . The above observations have potentially important implications relative to the immunity to infection.

Lab Anim Sci, 1997 Feb, 47(1), 27 - 35
Increased expression of vascular cell adhesion molecule-1 by the aortic endothelium of rabbits with Pasteurella multocida pneumonia; Richardson M et al.; Vascular cell adhesion molecule-1 (VCAM-1) is expressed by endothelial cells in a variety of inflammatory conditions in experimental animals and humans . It is increased in rabbit endothelium after the intravenous administration of endotoxin, after cholesterol feeding, in regeneration after injury, and in alloxan-induced diabetes mellitus . The effect of a respiratory tract infection with Pasteurella multocida, a common laboratory pathogen in rabbits, on VCAM-1 expression by aortic endothelial cells and on the endothelial ultrastructure was examined in specific-pathogen-free (SPF) New Zealand White rabbits infected by the instillation of a suspension of live organisms into the nose and in conventionally raised rabbits with naturally acquired P . multocida infection . Age-matched SPF rabbits maintained in a disease-free environment were controls . Rabbits were euthanized 50 days after infection, the aorta was excised, and the endothelial cells expressing VCAM-1 were identified by immunohistochemistry . Perfusion-fixed aortas from infected and SPF rabbits were prepared for examination by electron microscopy . All infected animals had pneumonitis and leukocytosis . In SPF rabbits the total leukocyte count was highest at postinfection day 25 . There was a significant (P < 0.05) increase in the number of VCAM-1-positive aortic endothelial cells in infected SPF rabbits (34 +/- 4/10(4) endothelial cells; n = 5) and rabbits with naturally acquired infection (57 +/- 14/10(4) endothelial cells; n = 5) compared with control animals (12 +/- 3 per 10(4) endothelial cells; n = 4) . The endothelium of infected rabbits had morphologic alterations consistent with injury . Thus infection at remote sites can activate arterial endothelium and induce the expression of VCAM-1.

J Vet Pharmacol Ther, 1997 Feb, 20(1), 17 - 20
Disposition of ofloxacin in female New Zealand white rabbits; Marangos MN et al.; Limited information exists regarding the disposition of ofloxacin in rabbits . Pharmacokinetic information is necessary for the design of appropriate therapeutic regimens for the treatment of organisms (e.g . Pasteurella multocida) commonly infecting this species . This study evaluated the pharmacokinetics of ofloxacin following intravenous (i.v.) and subcutaneous (s.c.) administration . Two groups of three female New Zealand White rabbits received a single dose of 20 or 40 mg/kg by the i.v . and s.c . routes . Samples were collected prior to drug administration, then 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, and 8 h postdose . Ofloxacin concentrations in serum were determined using a validated HPLC assay . Mean maximum concentrations were 66.86 +/- 10.83 mg/L and 14.1 +/- 2.20 mg/L for the i.v . and s.c . administration of 20 mg/kg . The 40 mg/kg dose produced maximum concentrations of 154.96 +/- 35.45 mg/L and 23.83 +/- 4.01 mg/L for the i.v . and s.c . doses, respectively . The area under concentration-time curve increased proportionally with the dose, while the half-life was unaltered and ranged from 1.5-1.9 h . From these data, it appears that a 20 mg/kg dose administered every 8 h by the s.c . route would optimize the pharmacodynamic profile of ofloxacin and provide an appropriate regimen for the treatment of many susceptible organisms which commonly infect this species.

FEMS Microbiol Lett, 1997 Feb 1, 147(1), 37 - 43
Comparison of the recombinant and authentic forms of the Pasteurella haemolytica A1 glycoprotease; Watt MA et al.; The O-sialoglycoprotein endopeptidase (glycoprotease, Gcp) is secreted by Pasteurella haemolytica A1, a Gram-negative pathogen associated with bovine pneumonic pasteurellosis . When the cloned gcp gene is expressed in Escherichia coli, the recombinant glycoprotease (rGcp) is exported to the periplasm but does not exhibit enzymatic activity . Polyclonal calf sera and murine monoclonal antibodies to rGcp were used for the further immunological and biochemical characterization of the authentic and recombinant Gcp . The results showed that the gcp gene product is the sole component of Gcp activity . Homologues to the P . haemolytica A1 Gcp were detected by Western immunoblot analysis in a number of Gram-negative bacteria, including E . coli . However, the secretion of Gcp with O-sialoglycoprotein endopeptidase activity appears to be restricted to P . haemolytica A serotypes.

J Bacteriol, 1997 Feb, 179(3), 871 - 9
Structure-function studies of the adenylate cyclase toxin of Bordetella pertussis and the leukotoxin of Pasteurella haemolytica by heterologous C protein activation and construction of hybrid proteins; Westrop G et al.; The adenylate cyclase toxin (CyaA) from Bordetella pertussis and the leukotoxin (LktA) from Pasteurella haemolytica are members of the RTX (stands for repeats in toxin) family of cytolytic toxins . They have pore-forming activity and share significant amino acid homology but show marked differences in biological activity . CyaA is an invasive adenylate cyclase and a weak hemolysin which is active on a wide range of mammalian cells . LktA is a cytolytic protein with a high target cell specificity and is able to lyse only leukocytes and platelets from ruminants . Each toxin is synthesized as an inactive protoxin encoded by the A gene, and the product of the accessory C gene is required for posttranslational activation . Heterologous activation of LktA by CyaC did not result in a change in its specificity for nucleated cells, although the toxin showed a greater hemolytic-to-cytotoxic ratio . LktC was unable to activate CyaA . A hybrid toxin (Hyb1), which contained the N-terminal enzymic domain and the pore-forming domain from CyaA (amino acids {aa} 1 to 687), with the remainder of the protein derived from the C-terminal end of LktA (aa 379 to 953), showed no toxic activity . Replacement of part of the LktA C-terminal domain of Hyb1 by the CyaA C-terminal domain (aa 919 to 1706) to create hybrid toxin 2 (Hyb2) partially restored toxic activity . In contrast to CyaA, Hyb2 was activated more efficiently by LktC than by CyaC, showing the importance of the region between aa 379 and 616 of LktA for activation by LktC . LktC-activated Hyb2 was more active against ruminant than murine nucleated cells, whereas CyaC-activated Hyb2 displayed a similar, but lower, activity against both cell types . These data indicate that LktC and the region with which it interacts have an influence on the target cell specificity of the mature toxin.

J Clin Microbiol, 1997 Feb, 35(2), 418 - 21
Identification and serotyping of Ornithobacterium rhinotracheale; van Empel P et al.; In the present study 443 strains of Ornithobacterium rhinotracheale, a causative agent of respiratory disease in fowl, were investigated biochemically and serologically . In both ways O . rhinotracheale could be differentiated from other gram-negative rods and, more particularly, from the Pasteurella-like bacteria potentially pathogenic for fowl . For the biochemical characterization of O . rhinotracheale the API 2ONE identification strip proved to be useful, although O . rhinotracheale is not included in the API system . Serologically, by using monovalent antisera in agar gel precipitation (AGP) tests and enzyme-linked immunosorbent assays (ELISAs), seven serotypes (serotypes A to G) of O . rhinotracheale could be discriminated . The AGP test was chosen as the preferred method to be used for serotyping . Isolates of serotype A were found to be the most prevalent, especially in chickens . Isolates from turkeys were more heterogeneously divided over the serotypes . Some strains showed cross-reactivity between serotypes A, B, and E . Five O . rhinotracheale strains could not be serotyped with the available antisera . Relationships between the geographic origin and the serotypes were found . By the ELISA the presence of antibodies against O . rhinotracheale could be detected in 1-day-old birds as well as in birds with clinical signs, and therefore, it might be useful for diagnostic purposes.

FEMS Microbiol Lett, 1997 Jan 15, 146(2), 181 - 8
Isolation and characterization of the integration host factor genes of Pasteurella haemolytica; Highlander SK et al.; Using a bacteriophage lambda complementation system in Escherichia coli, we cloned genes encoding subunits of the heterodimeric DNA binding/bending protein, integration host factor, from the bovine pathogen, Pasteurella haemolytica . Complementation of ihfA and ihfB mutations in E . coli demonstrated that the P . haemolytica gene products form functional heterologous heterodimers . The ihfA and ihfB genes encode polypeptides predicted to be 99 and 93 amino acids long, respectively, and are very similar to integration host factor subunits from other Gram-negative bacteria, although phylogenetic analysis indicated that the P . haemolytica sequences are distantly related to those from other bacteria . Most significant amino acid differences were restricted to the amino-terminal domains of the predicted peptides.

J Biol Chem, 1997 Jan 10, 272(2), 1268 - 75
Pasteurella multocida toxin activates the inositol triphosphate signaling pathway in Xenopus oocytes via G(q)alpha-coupled phospholipase C-beta1; Wilson BA et al.; Pasteurella multocida toxin (PMT) has been hypothesized to cause activation of a GTP-binding protein (G-protein)-coupled phosphatidylinositol-specific phospholipase C (PLC) in intact cells . We used voltage-clamped Xenopus oocytes to test for direct PMT-mediated stimulation of PLC by monitoring the endogenous Ca2+-dependent C1- current . Injection of PMT induced an inward, two-component Cl- current, similar to that evoked by injection of IP3 through intracellular Ca2+ mobilization and Ca2+ influx through voltage-gated Ca2+ channels . These PMT-induced currents were blocked by specific inhibitors of Ca2+ and Cl- channels, removal of extracellular Ca2+, or chelation of intracellular Ca2+ . Specific antibodies directed against an N-terminal, but not a C-terminal, peptide of PMT inhibited the toxin-induced currents, implicating that the N terminus of PMT is important for toxin activity . Injection with specific antibodies against PLCbeta1, PLCbeta2, PLCbeta3, or PLCgamma1 identified PLCbeta1 as the primary mediator of the PMT-induced Cl- currents . Injection with guanosine 5'-O-(2-(thio)diphosphate), antibodies to the common GTP-binding region of G-protein alpha subunits, or antibodies to different regions of G-protein beta subunits established the involvement of a G-protein alpha subunit in PMT-activation of PLCbeta1 . Injection with specific antibodies against the alpha-subunits of G(q/11), G(s/olf), G(i/o/t/z), or G(i-1/i-2/i-3) isoforms confirmed the involvement of Gq/11alpha . Preinjection of oocytes with pertussis toxin enhanced the PMT response . Overexpression of G(q)alpha in oocytes could enhance the PMT response by 30-fold to more than 300-fold, whereas introduction of antisense G(q)alpha cRNA reduced the response by 7-fold . The effects of various specific antibodies on the PMT response were reproduced in oocytes overexpressing G(q)alpha.

Dev Biol Stand, 1997, 90, 167 - 77
Immunization with bacterial antigens: pasteurellosis; Romalde JL et al.; Pasteurella piscicida is the aetiological agent of pasteurellosis or pseudotuberculosis, one of the most threatening diseases of wild and cultured marine fish . This bacterium has been reported from many geographical areas including USA, Japan, and the Mediterranean countries . In this review, the biochemical, serological, and molecular characteristics of the pathogen are described . In addition, its main virulence mechanisms, such as the presence of capsule, the iron uptake system, and the phospholipase activity, as well as their putative role in the pathogenicity of P . piscicida are also discussed . Finally, a detailed survey of the strategies for controlling the disease is performed, with a special emphasis on the vaccination programmes and the most effective protective antigens to be included in the vaccine formulations.

Antibiot Khimioter, 1997, 42(1), 37 - 44
{Pasteurella multocida: infections in man}; Stepanshin IuG et al.; The literature data on human infection due to a representative of the genus Pasteurella, i.e . P . multocida are reviewed: the main clinical forms and signs of pasteurellosis, the results of the studies on susceptibility of P . multocida to antibiotics and chemotherapeutics and the results of their use in the treatment of the infection.

Res Vet Sci, 1997 Jan-Feb, 62(1), 51 - 7
Development and characterisation of a model of bovine inflammation; Thomas LH et al.; Two dialysis sacs each containing 50 ml dextran sulphate solution were implanted into the peritoneal cavities of five three month-old calves . One sac was inoculated with Pasteurella haemolytica or Streptococcus uberis and the second sac served as an uninoculated control . Samples of sac fluid removed after 0, four, six, eight, 15, 24, 36 and 48 hours and then at 24 hour intervals after inoculation revealed bacterial growth up to 9.0 log10 cfu ml-1 by two to three days after inoculation . Concentrations of 25 to 48 ng ml-1 of the inflammatory mediator prostaglandin E2 (PGE2) were detected six to 96 hours after inoculation, similar amounts being generated in sacs inoculated with either bacterium, but the concentrations in control sacs remained below 10 ng ml-4 over the seven day experiment . Post mortem, a tissue cast invested each of the inoculated sacs . Histologically, the reaction was an acute inflammatory response similar to that evoked by each bacterium in the target organ.

Avian Dis, 1997 Jan-Mar, 41(1), 203 - 13
Lesions associated with Pasteurella multocida infection in raptors; Morishita TY et al.; Several case reports attest to the pathogenicity of Pasteurella multocida in raptors; however, the pathologic syndromes have not been fully described . We describe here the lesions encountered in 22 avian cholera cases in raptors . Besides septicemia-related lesions, a unique syndrome of esophageal abscesses was noted in 8 of the 11 (73%) Buteo hawks that succumbed to avian cholera . Esophageal abscesses were not noted in birds belonging to the order Strigiformes (owls) or family Falconidae (falcons and their relatives) . Thus, the presence of white plaques in both the oropharynx and esophagus of Buteo hawks may indicate a possible P . multocida infection and should be considered in the differential diagnosis . This study also documents the first cases of avian cholera in a rough-legged hawk (Buteo lagopus) and a flammulated owl (Otus flammeolus).

Plasmid, 1997, 37(1), 65 - 79
Characterization of a Pasteurella multocida plasmid and its use to express recombinant proteins in P . multocida; Wright CL et al.; The complete nucleotide sequence of a naturally occurring 5.36-kb streptomycin and sulphonamide resistance plasmid, designated pIG1, isolated from type D Pasteurella multocida was determined . A 1.6-kb noncoding region and a 1.4-kb region encoding three putative proteins were shown by sequence homologies and functional characterizations to be involved in the replication and mobilization of pIG1, respectively . The remaining sequence carried an unusual arrangement of streptomycin- and sulphonamide-resistant genes when compared to various other plasmids . It appears that the antibiotic resistance region of pIG1 may have evolved by recombination between three different short direct repeat DNA sequences . A 4.5-kb recombinant plasmid was constructed by replacing the antibiotic resistance genes of pIG1 with a kanamycin resistance gene and seven unique restriction sites . The resulting plasmid, designated pIG112, stably replicates in P . multocida, Pasteurella haemolytica, Actinobacillus pleuropneumoniae, and Escherichia coli and can be introduced into these organisms by either transformation or conjugation . This vector exists at approximately 70 copies per cell in P . multocida and approximately 20 copies per cell in E . coli . To demonstrate plasmid-borne gene expression in P . multocida, the P . multocida dermonecrotic toxin gene, toxA, and a genetically modified form of this gene were cloned into pIG112 and expressed in high amounts in a nontoxigenic P . multocida strain . Cell culture assays demonstrated that nontoxigenic P . multocida expressing toxA was cytopathic, whereas a strain expressing the modified toxA derivative was not.

Vet Microbiol, 1997 Jan, 54(1), 23 - 34
Mycoplasma hyopneumoniae infection in pigs: duration of the disease and evaluation of four diagnostic assays; Sorensen V et al.; 200 SPF pigs were infected by aerosol with Mycoplasma hyopneumoniae and the development of clinical signs, serological and pathological reactions were studied . Mean time to onset of coughing was 13 days . A mean delay of 9 days was observed from onset of coughing until seroconversion against M . hyopneumoniae as measured by ELISA . At an individual level, the sensitivity for this ELISA was estimated to 98-100% and the specificity to 93-100% . Pasteurella multocida was isolated from the majority of the lungs 4 weeks post inoculation with M . hyopneumoniae and the lung lesions in pigs were significantly larger when P . multocida was present as compared to pigs with M . hyopneumoniae alone . An evaluation of cultivation, immunofluorescence, ELISA and polymerase chain reaction for demonstration of M . hyopneumoniae in lungs showed that all four methods have a high sensitivity in the acute stages of pneumonia . In the later stages the sensitivity of cultivation was superior to the other methods . No differences in specificity were observed between the methods . The antigen-ELISA OD values and the immunofluorescence scores revealed a strong positive correlation . Nasal swabs were additionally used for demonstration of M . hyopneumoniae and the polymerase chain reaction was found superior to the other methods.

J Vet Med Sci, 1997 Jan, 59(1), 75 - 8
Bacterial isolation from slaughtered pigs associated with endocarditis, especially the isolation of Streptococcus suis; Katsumi M et al.; Bacterial isolation from slaughtered pigs with endocarditis was carried out from 1985 to 1994 . A total of 495 (0.025%) out of 2,006,127 pigs were diagnosed as having endocarditis . Though bacteria were significantly isolated from 399 of the 495 pigs, bacteria could not be isolated in 96 pigs (19.4%) . In 11 pigs, 2 bacterial species were isolated from heart lesion . Streptococcus suis was isolated from 127 cases (25.7%), Streptococcus dysgalactiae from 75 (15.2%), Erysipelothrix rhusiopathiae from 63 (12.7%), Actinomyces pyogenes from 39 (7.9%), Pasteurella multocida from 11 (2.2%) . Staphylococcus aureus from 10 (2.0%), and Streptococcus porcinus from 8 (1.6%) . Among the 99 isolates biochemically identified as S . suis, the major serotype was S . suis type 2 (35.4%) . The remainder of the typable isolates were identified as serotypes 1/2 (2.0%) and 9 (1.0%) . A total of 61 isolates (61.6%) were untypable.

J Vet Med Sci, 1997 Jan, 59(1), 55 - 7
Effect of Bordetella bronchiseptica and serotype D Pasteurella multocida bacterin-toxoid on the occurrence of atrophic rhinitis after experimental infection with B . bronchiseptica and toxigenic type AP . multocida; Sakano T et al.; In efficacy tests, 7 primary specific-pathogen-free piglets vaccinated with the Bordetella bronchiseptica and type D Pasteurella multocida bacterin-toxoid were challenged with B . bronchiseptica and type A P . multocida . Severe or moderate nasal turbinate atrophy was produced in the non-vaccinated pigs, whereas, only one of the 4 pigs in the vaccinated group had slight turbinate atrophy . Other immune sera against crude toxin of P . multocida type A or D were cross neutralized . The results of the present study show that the P . multocida serotype D bacterin-toxoid is effective against atrophic rhinitis caused by toxigenic P . multocida serotype A as well as toxigenic P . multocida serotype D.

Aust Vet J, 1997 Jan, 75(1), 52 - 5
Characterisation of Australian isolates of Actinobacillus capsulatus, Actinobacillus equuli, Pasteurella caballi and Bisgaard Taxa 9 and 11; Blackall PJ et al.; OBJECTIVE: The objective of this work was to perform a comprehensive phenotypic characterisation of 16 isolates of bacteria previously identified as Actinobacillus equuli . DESIGN: The 16 isolates that had been obtained from Australian animals--15 from horses and one from a rabbit--were compared with reference strains of A equuli, A capsulatus, Pasteurella caballi and Bisgaard Taxa 9 and 11 . RESULTS: The characterisation study demonstrated that only nine of the isolates were A equuli . The other isolates were identified as A capsulatus (the isolate from rabbit), P caballi (one isolate), Bisgaard Taxon 11 (two isolates) and Bisgaard Taxon 9 (one isolate) . The final two isolates could not be assigned to any recognised species or taxa . CONCLUSION: This study has highlighted the importance of a complete characterisation of Actinobacillus-like organisms isolated from horses and rabbits . The study represents the first time that A capsulatus, P caballi and Bisgaard Taxa 9 and 11 have been recognised as being present in Australia.

Comp Immunol Microbiol Infect Dis, 1997 Jan, 20(1), 29 - 34
Phenotype and serotype of Pasteurella multocida isolates from diseases of dogs and cats in Zimbabwe; Mohan K et al.; A variety of disease manifestations, comprising skin bite wounds, pyothorax, respiratory and genitourinary tract infections, in 202 dogs and cats presented to the University Clinic, were investigated for the presence of Pasteurella multocida . Of these, 25-42% of various cases (69) were found to be infected with P . multocida . P . multocida-associated respiratory tract infections were more common than bite wounds or genitourinary tract infections . The regimen of treatment consisted of those antibiotics, sensitivity to which had been confirmed in vitro . Following detailed characterization of the isolates of P . multocida, in order to assign them to the reclassified taxa of Pasteurella, a preponderance of P . multocida subspecies multocida and septica were recorded . There did not appear to be a correlation between the reclassified taxa and their serotypes . Certain strains of different species or subspecies belonged to a common serotype and vice versa . However, the strains which were serotyped belonged to capsular type A, except for a solitary isolate from a cat which was capsular type D . Type D is known to cause atrophic rhinitis and does not appear to have been isolated either from a dog or a cat . Two strains, one from a dog and another from a cat, were identified as group EF-4 bacteria . This group of organisms has been incriminated in human wounds resulting from dog/cat bites, and has so far not been reported in Africa . Three different species, P . stomatis, P . dagmatis and P . multocida subspecies multocida were simultaneously isolated from a case of chronic bronchitis in a dog . There was no evidence of any relationship between disease manifestation in a host and the isolation of a particular taxon of Pasteurella, except that P . canis and Pasteurella taxon 16 were only isolated from dogs.

Cell Tissue Res, 1997 Jan, 287(1), 223 - 30
Response of eosinophilic granule cells of gilthead seabream (Sparus aurata, Teleostei) to bacteria and bacterial products; Noya M et al.; Eosinophilic granule cells in the gills and peritoneal exudate of gilthead seabream (Sparus aurata L.) are characterized by the presence of prominent eosinophilic granules in their cytoplasm and are here described for the first time . The oval granules of these cells contain an electron-dense inclusion surrounded by a less dense filamentous matrix and are peroxidase- and acid phosphatase-negative . Unlike other granulocytes of gilthead seabream, eosinophilic granule cells do not ingest bacteria in vivo . The intraperitoneal injection of extracellular products of Pasteurella piscicida induces mobilization of eosinophilic granule cells to the blood and other tissues and causes changes in their structure . Shortly after injection, the granules of eosinophilic granule cells become swollen and some fuse with the cell membrane . From 7 h post-injection, many eosinophilic granule cells in the gills degenerate and are then phagocytosed by macrophages, which are especially abundant after 24 h . From 24 h to 72 h, eosinophilic granule cells from the gills contain abundant autolysosomes together with granules of a normal morphology.

Am J Vet Res, 1997 Jan, 58(1), 28 - 33
Role of tissue factor in intra-alveolar fibrin deposition and coagulopathy associated with pneumonic pasteurellosis in cattle; Rashid J et al.; OBJECTIVE: To determine the role of tissue factor (TF) in the coagulation events leading to intra-alveolar fibrin deposition and intravascular thrombosis associated with pneumonic pasteurellosis in cattle . ANIMALS: Healthy 2- to 4-week-old male Holstein calves . PROCEDURES: Blood and bronchoalveolar lavage samples were collected before and at 1, 2, 4, and 6 hours after inoculation of saline solution or Pasteurella haemolytica . Total leukocyte count, platelet count, plasma total protein concentration, prothrombin time, and partial thromboplastin time were measured in blood samples . Total nucleated cell count, total protein concentration, and procoagulant activity were measured in bronchoalveolar lavage samples . Additionally, platelet survival in blood platelet accumulation in affected lung tissue, and gross and microscopic lung lesions were determined . RESULTS: Administration of TF monoclonal antibodies (MAB) TF1-1F7 prevented the decrease in platelet survival and the increase in bronchoalveolar lavage fluid TF-dependent procoagulant activity observed in calves not treated with MAB TF1-1F7 antibody, but did not attenuate the increase in lavage fluid neutrophil numbers and total protein concentration, MAB TF1-1F7 administration reduced the percentage of lung affected by pneumonic lesions from 51.81% to 10.40% and attenuated intra-alveolar deposition of fibrin, neutrophils, and erythrocytes . CONCLUSION: Intra-alveolar fibrin deposition and activation of coagulation in cattle with pneumonic pasteurellosis is, at least in part, mediated by TF . CLINICAL RELEVANCE: Treatments that neutralize TF activity may attenuate lung injury in cattle with pneumonic pasteurellosis.

Infect Immun, 1997 Jan, 65(1), 339 - 43
Identification, purification, and characterization of the type 4 fimbriae of Pasteurella multocida; Ruffolo CG et al.; The presence of fimbriae on Pasteurella multocida has been reported, but there have been no prior studies aimed at conclusively characterizing these structures . We now report on the identification and characterization of type 4 fimbriae on serogroup A, B, and D strains of P . multocida . Under microaerophilic conditions P . multocida showed an increased expression of the fimbriae, which were observed to form bundles . Fimbriae purified by high-performance reverse-phase liquid chromatography constituted a single 18-kDa subunit, the first 21 amino acids of which shared very high similarity with the N-terminal amino acid sequence of other type 4 fimbrial subunits . Antiserum against the P . multocida 18-kDa protein immunostained the type 4 fimbrial subunit of Moraxella bovis and Dichelobacter nodosus . Based on these observations we conclude that P . multocida possesses type 4 fimbriae and have designated the P . multocida fimbrial subunit PtfA.

Infect Immun, 1997 Jan, 65(1), 211 - 8
Purification and partial characterization of the OmpA family of proteins of Pasteurella haemolytica; Mahasreshti PJ et al.; This study was conducted to partially characterize and identify the purity of two major outer membrane proteins (OMPs) (with molecular weights of 32,000 and 35,000 {32K and 35K, respectively}) of Pasteurella haemolytica . The 35K and 32K major OMPs, designated Pasteurella outer membrane proteins A and B (PomA and PomB, respectively), were extracted from P . haemolytica by solubilization in N-octyl polyoxyl ethylene . The P . haemolytica strain used was a mutant serotype A1 from which the genes expressing the 30-kDa lipoproteins had been deleted . PomA and PomB were separated and partially purified by anion-exchange chromatography . PomA but not PomB was heat modifiable . The N-terminal amino acid sequences of the two proteins were determined and compared with reported sequences of other known proteins . PomA had significant N-terminal sequence homology with the OmpA protein of Escherichia coli and related proteins from other gram-negative bacteria . Moreover, polyclonal antiserum raised against the E . coli OmpA protein reacted with this protein . PomA was surface exposed, was conserved among P . haemolytica biotype A serotypes, and had porin activity in planar bilayers . No homology between the N-terminal amino acid sequence of PomB and those of other known bacterial proteins was found . Cattle vaccinated with live P . haemolytica developed a significant increase in serum antibodies to partially purified PomA, as shown by enzyme-linked immunosorbent assays, and to purified PomA and PomB, as detected on Western blots and by densitometry.

J Clin Microbiol, 1997 Jan, 35(1), 208 - 12
Detection of Antibodies to Pasteurella multocida by capture enzyme immunoassay using a monoclonal antibody against P37 antigen; Peterson RR et al.; As infection with Pasteurella multocida is common in rabbits, an enzyme immunoassay (EIA) was developed for its detection . A murine immunoglobulin G monoclonal antibody was used to capture a 37-kDa polypeptide of P . multocida serotype A:12 in an EIA to detect antibodies to P . multocida . The 37-kDa antigen was selected since it was previously shown to be a major immunogen during P . multocida infection in rabbits . The sensitivity of the P37 EIA, determined with sera from 56 rabbits infected with P . multocida, was 98% . Specificity, evaluated with sera from 62 rabbits from colonies free of P . multocida, was 92% . Titration curves of sera from rabbits immunized with P . multocida serotype A:3 or A:12 coincided, indicating that the P37 EIA was equally efficient in detecting antibodies to the two major serotypes of the organism . Comparison of the P37 EIA with the current serodiagnostic test, a bacterial lysate EIA, revealed relatively good correlation (r = 0.68) . However, specificity was greatly improved, as 34% of uninfected rabbits were falsely positive by the lysate EIA whereas only 3% of uninfected rabbits were falsely positive by the P37 EIA . The coefficient of variation for same-day tests was 10%, and that for interday tests was 15%, indicating good reproducibility . The greater sensitivity and specificity of the P37 EIA should significantly enhance diagnostic capability to identify rabbits infected with P . multocida.

Biologicals, 1996 Dec, 24(4), 325 - 8
Effects of interactions between Pasteurella haemolytica and Bordetella parapertussis on in vitro phagocytosis by lung macrophages; Hodgson JC et al.; The aim of the work was to determine the effect of exposing ovine bronchoalveolar macrophages (BAM) in vivo to Pasteurella haemolytica and/or Bordetella parapertussis on the subsequent uptake and killing of P . haemolytica by these cells in vitro . Exposure in vivo to P . haemolytica did not affect the uptake of P . haemolytica by BAM in vitro but reduced (P < 0.05) the intracellular killing of bacteria . Exposure in vivo to B . parapertussis had no significant effect on either the uptake or killing of P . haemolytica in vitro . However, sequential exposure in vivo to B . parapertussis and P . haemolytica reduced both the ingestion (P < 0.05) and killing (P < 0.001) of P . haemolytica in vitro . These results indicate that exposure to P . haemolytica compromised the bacterial killing mechanisms of BAM and that synergy between B . parapertussis and P . haemolytica reduced the ability of BAM to ingest bacteria.

Vet Immunol Immunopathol, 1996 Dec, 55(1-3), 73 - 82
Effects of BHV-1 on PMN adhesion to bovine lung endothelial cells; Warren LM et al.; Bovine herpes virus-1 (BHV-1) infection appears to decrease the rate of polymorphonuclear leukocyte (PMN) influx into the lung in response to the secondary invader, Pasteurella haemolytica . It was postulated that BHV-1 may affect the rate of cellular infiltration by altering the function of the endothelium, thereby preventing PMN movement across the blood-tissue barrier . Therefore, we decided to investigate the effect of BHV-1 on the ability of PMN to adhere to lung endothelial cells (LEC) . LEC were isolated from fetal bovine fetal tissue and were shown to function in PMN adhesion assays . Furthermore, enhanced PMN adhesion was observed after exposure of LEC to recombinant bovine TNF-alpha (rBoTNF-alpha) for 4, 8, 12, and 24 h . LEC infected with BHV-1 were shown to be less responsive to rBoTNF-alpha . However, infection of LEC with BHV-1 at an multiplicity of infection (MOI) of 1.0 or 10 did not affect basal levels of PMN adhesion to these cells . Decreased PMN binding to BHV-1-infected LEC, simultaneously treated with rBoTNF-alpha, was observed at 10-12 h post-infection . The data suggest that BHV-1 may prevent cytokine-induced PMN infiltration of the lung through the modification of EC responses to cytokines.

Zentralbl Veterinarmed B, 1996 Dec, 43(10), 585 - 91
Differentiation of Pasteurella multocida subspecies multocida isolates from the respiratory system of pigs by using polymerase chain reaction fingerprinting technique; Zucker B et al.; PCR fingerprinting technique was applied to subtype 44 Pasteurella multocida subspecies multocida (P.m.sp.m.) isolates from the respiratory system of pigs . Two single primers were tested for their abilities to generate individual fingerprints by using PCR . Primer 1 (core sequence of the M13 phage) grouped the 44 P.m.sp.m . strains into five distinct fingerprinting profiles, while primer 2 ((GACA)4) grouped them into seven profiles . The results suggest that PCR fingerprinting is an efficient technique to detect DNA polymorphism in the species P.m.sp.m . This technique could be used to differentiate P.m.sp.m . strains of the same capsular serotype.

Vet Microbiol, 1996 Dec, 53(3-4), 303 - 14
Characterization of an outer membrane protein of Pasteurella multocida belonging to the OmpA family; Marandi M et al.; The outer membrane vesicle and N-lauroylsarcosine-insoluble protein preparations of Pasteurella multocida 656 were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis . A major outer membrane protein (OMP) was found to be heat-modifiable, having a molecular mass of 28 kDa when the OMP preparation was solubilized at 60 degrees C and a molecular mass of 37 kDa when it was solubilized at 100 degrees C . A monoclonal antibody, designated mAb MT4.1, was generated against heat-modifiable OMP of P . multocida . This mAb reacted with the heat-modifiable OMP irrespective of the temperature at which it was solubilized, as demonstrated by immunoblot results . The heat-modifiable OMP of P . multocida showed a significant N-terminal amino acid sequence homology with OmpA family . Immunoelectron microscopic study revealed that the mAb Mt4.1 epitope was not surface exposed on the intact bacterium . The mAb MT4.1 reacted with all the reference strains of 5 capsular and 16 somatic serotypes, as well as with 75 field strains of P . multocida in immunoblot assay . This mAb MT4.1 also reacted with strains of various other Pasteurella species such as P . stomatis, P . aerogenes P . gallinarum, P . betti, P . sp, B, P . SP-g and P . canis, but not with strains of 12 other Gram-negative bacteria . These results indicated that this protein carried a genus-specific epitope and mAb MT4.1 may be useful for identification of Pasteurella species . This is the first report in which a major heat-modifiable OMP has been identified and characterized using a mAb, and has been shown belonging to the OmpA family.

Vet Q, 1996 Dec, 18(4), 141 - 6
Effect of Pasteurella multocida toxin on in vivo immune responses in piglets; van Diemen PM et al.; Atrophic rhinitis is characterized by a lack of an immune response towards Pasteurella multocida toxin (Pm-T) . The effects of intranasal administration of Pm-T on cellular and T-cell dependent antibody responses of piglets against various other antigens were studied in a 3 by 2 factorial arrangement of treatments: three levels of challenge with Pm-T (either once; on three consecutive days; or no Pm-T challenge), and with or without simultaneous immunization with a "cocktail' containing Keyhole limpet haemocyanin (KLH), ovalbumin (OA) and tetanus toxoid (TT) . Challenge with Pm-T affected but did not abolish the in vivo humoral immune response against OA, KLH, or TT . Pigs treated once with Pm-T showed lower total antibody responses, caused by lower IgG responses to the antigens . We found no clear consistent effects of Pm-T on cellular immune responses to the various T-cell-dependent antigens in vitro . The lack of immune responsiveness to Pm-T in Pm-T challenged pigs is discussed . The absence of detectable immune responses does not depend on a general suppression of the cellular immune system.

J Clin Microbiol, 1996 Dec, 34(12), 3035 - 9
Direct PCR analysis for toxigenic Pasteurella multocida; Lichtensteiger CA et al.; A more rapid, accurate method to detect toxigenic Pasteurella multocida is needed for improved clinical diagnosis, farm biosecurity, and epidemiological studies . Toxigenic and nontoxigenic P . multocida isolates cannot be differentiated by morphology or standard biochemical reactions . The feasibility of using PCR for accurate, rapid detection of toxigenic P . multocida from swabs was investigated . A PCR protocol which results in amplification of an 846-nucleotide segment of the toxA gene was developed . The PCR amplification protocol is specific for toxigenic P . multocida and can detect fewer than 100 bacteria . There was concordance of PCR results with (i) detection of toxA gene with colony blot hybridization, (ii) detection of ToxA protein with colony immunoblot analysis, and (iii) lethal toxicity of sonicate in mice in a test set of 40 swine diagnostic isolates . Results of an enzyme-linked immunosorbent assay for ToxA agreed with the other assays except for a negative reaction in one of the 19 isolates that the other assays identified as toxigenic . In addition to accuracy, as required for a rapid direct specimen assay, toxigenic P . multocida was recovered efficiently from inoculated swabs without inhibition of the PCR . The results show that PCR detection of toxigenic P . multocida directly from clinical swab specimens should be feasible.

Zhonghua Yi Xue Za Zhi (Taipei), 1996 Nov, 58(5), 374 - 9
Pelvic inflammatory pseudotumor with central infectious abscess: a case report; Han CP et al.; Inflammatory pseudotumors (IPT) are a fascinating group of lesions which involve almost all organs and tissues of the body . The clinical manifestations are diverse . Final diagnosis can only be made by meticulous microscopic examination of different areas of the tumor . A 60 year-old woman had a pelvic IPT with central infectious abscess . The lesion involved her urinary bladder, mesentery, terminal ileum, right rudimentary ovary and the abdominal wall . It mimicked malignant tumor clinically, and led to total surgical excision . Early follow-up has shown a favorable results . IPTs are extremely uncommon . The characteristic pathologic picture is a reparative fibroblastic tissue infiltrated by polymorphic inflammatory cells . Pelvic IPT, admixed with central infectious abscess, is even rarer . Prior pelvic surgery and pasteurella hemolytica infection might be causative factors in this reported case.

Vet Immunol Immunopathol, 1996 Nov, 54(1-4), 197 - 204
Restricted B-cell responses to microbial challenge of the respiratory tract; Walker J et al.; The local B-cell response in the respiratory tract to infectious challenge has been analyzed in pigs and calves using two techniques: flow cytometry and antibody secreting cell (ASC) probes . Pneumonia in pigs caused by experimental infection with Mycoplasma hyopneumoniae resulted in a 25-fold increase in the B-cell population in BAL and lung parenchyma 28 days post infection . ASC probes revealed that the B-cell response of immune pigs to a large challenge infection was localized to lung parenchyma and tracheobronchal lymph nodes . Naive calves infected with Pasteurella multocida had a 5-fold increase in the B-cell blast population in lung parenchyma and BAL, and a greater than 60-fold increase in the draining lymph node at 9 days post infection . The ASC probes prepared post challenge from immune calves showed the response to be localized to the draining lymph nodes, with little response in lung parenchyma . A major finding was that ASC probes prepared from lung parenchyma and from pulmonary lymph nodes of both calves and pigs recognized a restricted range of bacterial antigens, particularly compared to the range of antigens recognized by concurrently circulating sera . The use of ASC probes demonstrates that there is a restricted B-cell repertoire in the respiratory tract.

Vet Pathol, 1996 Nov, 33(6), 639 - 46
Passage of CD18- and CD18+ bovine neutrophils into pulmonary alveoli during acute Pasteurella haemolytica pneumonia; Ackermann MR et al.; CD18 is a subunit for three beta 2 integrin molecules (Mac-1, p150, 95, LFA-1), which are expressed on the plasma membrane of neutrophils . These molecules mediate passage of neutrophils into sites of infection . In children and animals that lack CD18 expression, neutrophil infiltration is impaired in most tissues . However, in lung, CD18- neutrophils have been identified in the airway spaces during spontaneous episodes of pneumonia . To determine whether CD18 is vital for passage through the pulmonary alveolar wall, lung lobes of cattle with neutrophils that were deficient in CD18 expression (CD18-) and cattle with normal CD18 expression (CD18+) were inoculated with Pasteurella haemolytica by fiberoptic bronchoscopy; control lobes were inoculated with pyrogen-free saline (PFS) . Neutrophil passage into alveolar lumina at 4 and 6 hours postinoculation was measured by computerized image analysis . Blood levels of neutrophils for CD18- cattle ranged from 12- to 26-fold higher than for CD18+ cattle prior to inoculation, and counts in both groups rose slightly postinoculation . In P . haemolytica-inoculated lobes, total numbers of neutrophils in alveolar lumina of the two groups were similar . An increase in the number of neutrophils in the alveolar wall was fourfold greater in CD18- cattle than in CD18+ cattle . In PFS-inoculated lobes, the number of neutrophils in the alveolar wall was sixfold higher in CD18 cattle than in CD18+ cattle . This work shows that by 4 and 6 hours, CD18- neutrophils enter the alveolar lumen at a rate similar to that in CD18+ cattle . Higher numbers of CD18- neutrophils are present in the alveolar wall of control (PFS) and bacteria-inoculated lobes . Thus, the CD18- cells are increased in the walls of alveoli and numbers of neutrophils that enter the alveolar lumen are similar in CD18+ and CD18- cattle.

Res Vet Sci, 1996 Nov, 61(3), 199 - 205
Cloning of a unique sequence specific to isolates of type B:2 Pasteurella multocida; Townsend KM et al.; Two Carter type B Pasteurella multocida isolates, Izatnagar 52 and 25, isolated from cases of haemorrhagic septicaemia (HS), were used in a modified subtractive hybridisation technique with the specific aim of cloning unique DNA sequences related to the pathogenesis of HS . Biochemical and protein analyses have shown these isolates to be similar, but reports indicate that they have differences in pathogenicity . The subtracted inserts were screened against genomic DNA from a wide range of P multocida isolates, with two distinct fragments demonstrating specific hybridisation with Carter type B isolates that cause HS . No identity was observed with either Carter type E isolates or non-HS type B strains . The clones were sequenced and a search of the GenBank database revealed significant identity of the clone A3b (296 nt) to P haemolytica lipoprotein, whereas there was no significant identity with 6b (956 nt) . Both these fragments had a high level of identity (72.8 to 76.9 per cent) to the H influenzae Rd genome.

Antimicrob Agents Chemother, 1996 Nov, 40(11), 2610 - 7
Species selectivity of new siderophore-drug conjugates that use specific iron uptake for entry into bacteria; Diarra MS et al.; Siderophores selectively bind ferric iron and are involved in receptor-specific iron transport into bacteria . Several types of siderophores were synthesized, and growth-promoting or inhibitory activities when they were conjugated to carbacephalosporin, erythromycylamine, or nalidixic acid were investigated . Overall, 11 types of siderophores and 21 drug conjugates were tested against seven different bacterial species: Escherichia coli, Bordetella bronchiseptica, Pasteurella multocida, Pasteurella haemolytica, Streptococcus suis, Staphylococcus aureus, and Staphylococcus epidermidis . In some species, the inhibitory activities of the drug conjugates were associated with the ability of the bacteria to use the siderophore portion of the molecules for growth promotion in disc diffusion tests (0.04 mumol of conjugate or siderophore per disc) . E . coli used catechol-based siderophore portions as well as hydroxamate-based tri-delta-OH-N-OH-delta-N-acetyl-L-ornithine ferric iron ligands for growth under iron-restricted conditions achieved by supplemental ethylenediamine di (O-hydroxyphenylacetic acid) (100 micrograms/ml) and was sensitive to carbacephalosporin conjugated to these siderophore types (up to a 34-mm-diameter inhibition zone) . B . bronchiseptica used desferrioxamine B and an isocyanurate-based or trihydroxamate in addition to catechol-based siderophore portions for promotion but was not inhibited by beta-lactam conjugates partly because of the presence of beta-lactamase . P . multocida and P . haemolytica did not use any of the synthetic siderophores for growth promotion, and the inhibitory activities of some conjugates seemed partly linked to their ability to withhold iron from these bacteria, since individual siderophore portions showed some antibacterial effects . Individual siderophores did not promote S . suis growth in restrictive conditions, but the type of ferric iron ligands attached to beta-lactams affected inhibitory activities . The antibacterial activities of the intracellular-acting agents erythromycylamine and nalidixic acid were reduced or lost, even against S . aureus and S . epidermidis, when the agents were conjugated to siderophores . Conjugate-resistant E . coli mutants showed the absence of some iron-regulated outer membrane proteins in gel electrophoresis profiles and in specific phage or colicin sensitivity tests, implying that the drugs used outer membrane receptors of ferric complexes to get into cells.

Infect Immun, 1996 Nov, 64(11), 4665 - 72
Association of RTX toxins with erythrocytes; Bauer ME et al.; A critical step in the target cell attack by RTX cytotoxins is their association with target cells . A binding assay was used to study the association of the Escherichia coli hemolysin protein (HlyA) with erythrocytes . Several parameters required for lysis by HlyA were tested for their effects on its initial association with erythrocytes . The results demonstrate that HlyA binding to target cells is independent of several structural components of the active toxin, including the N-terminal hydrophobic region, the glycine-rich repeat region, and the HlyC-dependent acylation of HlyA . Further, the association with erythrocytes was independent of Ca2+ concentration or temperature, while the lytic event is both Ca2+ dependent and temperature dependent . The association of two other RTX toxin proteins, the Pasteurella haemolytica leukotoxin (LktA) and the enterohemorrhagic E . coli toxin (EhxA), were also examined; these toxins bound to erythrocytes much less efficiently than did HlyA . The association of HlyA with erythrocytes occurred rapidly, within 12 s of incubation, and demonstrated no measurable dissociation . HlyA bound to erythrocytes with a maximum of approximately 2,000 molecules per cell . Competition between active HlyA and unacylated HlyA demonstrated no inhibition of binding by unacylated HlyA; rather, active HlyA appeared to displace unacylated HlyA on the cell surface . These data demonstrate that binding and lysis by HlyA are separable events and challenge the concept of nonspecific binding to the cell surface by RTX toxins.

Avian Dis, 1996 Oct-Dec, 40(4), 908 - 18
Pasteurella multocida in raptors: prevalence and characterization; Morishita TY et al.; Several cases dealing with Pasteurella multocida infection have been documented in raptors . However, the isolates have not been fully characterized nor has the prevalence of P . multocida in raptors been determined . Three hundred ninety-eight raptors were cultured for P . multocida . Results indicated that P . multocida was not normally carried in the pharyngeal, choanal, or cloacal regions . However, P . multocida was isolated from raptors with avian cholera . Isolates from eight cases were characterized by biotype, somatic serotype, and antibiogram . Most (six of eight) of the P . multocida isolates belonged to somatic serotype 1 . The remaining two P . multocida isolates belonged to somatic serotypes 3 and 3,4 . The majority of the isolates belonged to the subspecies multocida . All isolates were susceptible to penicillin G, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole . Various restriction site heterogeneities of P . multocida chromosomal DNA were found among the raptor isolates . Results indicated that isolates of P . multocida somatic serotype 1 from diurnal raptors were genetically related.

Avian Dis, 1996 Oct-Dec, 40(4), 900 - 7
Pasteurella multocida in psittacines: prevalence, pathology, and characterization of isolates; Morishita TY et al.; Although the pathogenicity of Pasteurella multocida for psittacines (parrots and their relatives) has been documented in several case reports, the associated pathologic syndromes have not been well defined nor have the isolates been characterized . In addition, the prevalence of P . multocida in psittacines has not been determined . Three hundred twenty-eight psittacines (253 clinically healthy and 75 clinically ill) were cultured for P . multocida . Pasteurella multocida was not isolated from the pharynx, choana, or cloaca of psittacines . However, in five dead psittacines submitted for necropsy, P . multocida was isolated . These isolates were characterized, and all belonged to either somatic serotype 3 or 4,7 . Pasteurella multocida somatic serotype 3 was isolated from psittacines with septicemia, whereas P . multocida somatic serotype 4,7 was isolated from psittacines with cutaneous lesions . The majority (four out of five) of the P . multocida isolates belonged to the subspecies multocida, and all isolates were susceptible to penicillin G, sulfisoxazole, gentamicin, erythromycin, tetracycline, and trimethoprim-sulfamethoxazole but resistant to streptomycin . DNA fingerprints demonstrated that isolates belonging to the same somatic serotype were genetically related . The isolate from a cockatiel that had been caught by a cat belonged to somatic serotype 3 and was not genetically related to the other two isolates belonging to this somatic serotype.

Avian Dis, 1996 Oct-Dec, 40(4), 887 - 93
Capsular hyaluronic acid-mediated adhesion of Pasteurella multocida to turkey air sac macrophages; Pruimboom IM et al.; Serogroup A strains of Pasteurella multocida, the major cause of fowl cholera, are resistant to phagocytosis in nonimmunized birds . Adherence studies with a capsulated strain of P . multocida (serotype A:3) and turkey air sac macrophages in culture showed that the bacteria were capable of adhering in large numbers to the macrophages but were not internalized . A noncapsulated variant of the bacteria (serotype -:3) showed little or no adherence and was not internalized . These data indicated that the adhesive properties were caused by the presence of a capsule on the bacteria . The role of capsular hyaluronic acid in adherence to macrophages was investigated . Depolymerization of the bacterial capsule with hyaluronidase increased phagocytosis by macrophage cultures, and addition of hyaluronic acid to the macrophages inhibited bacterial adherence . Additionally, exposure of macrophages to chondroitin sulfate B, an anionic polysaccharide similar to hyaluronic acid, did not affect the adhesive properties and resistance to phagocytosis of capsulated organisms . Treatment of macrophages with sodium metaperiodate or trypsin suppressed bacterial binding . Collectively, these data indicate that P . multocida adhesion to air sac macrophages, but not internalization, is mediated by capsular hyaluronic acid and suggest that recognition of this bacterial polysaccharide is a result of a specific glycoprotein receptor.

Vet Microbiol, 1996 Oct, 52(3-4), 301 - 11
Immunogenicity of outer membrane protein of Pasteurella multocida in buffalo calves; Pati US et al.; Outer membrane protein (OMP) from Pasteurella multocida serotype B:2 was extracted and characterized using SDS-PAGE . Ten major polypeptide bands of MW 88 to 25 kDa were observed . Immunoblotting suggested that the polypeptides of MW 44, 37 and 30 kDa were the major immunogens . Buffalo calves vaccinated with the OMP vaccine or a commercial haemorrhagic septicaemia oil adjuvant vaccine developed highest mean log10 ELISA titres day 21 postvaccination (pv) . Antibody titres detectable in these animals using an indirect haemagglutination assay were lower than the ELISA titres but the pattern of the antibody response was similar . A passive mouse protection assay revealed that the maximum protection against the challenge infection was conferred by the serum collected from both the groups on day 21 pv and 26 pv . Following challenge with virulent P . multocida cells, all the five OMP vaccinated animals survived whereas only 2 out of the 3 HS oil adjuvant vaccinated animals withstood the challenge . Results suggested that OMP was protective and could be used in vaccines against haemorrhagic septicaemia.

J Vet Diagn Invest, 1996 Oct, 8(4), 464 - 8
Interpretive criteria for antimicrobial susceptibility testing of ceftiofur against bacteria associated with swine respiratory disease; Burton PJ et al.; Ceftiofur, an extended-spectrum cephalosporin, is active against a variety of animal pathogens, including organisms associated with swine respiratory disease . However, minimum inhibitory concentration (MIC) breakpoint and disk diffusion interpretive criteria have not been established for swine pathogens . Susceptibility tests were performed by broth microdilution MIC and disk diffusion methods on 246 bacterial species that cause swine respiratory disease . Ceftiofur was active against Salmonella sp., Pasteurella multocida, Actinobacillus pleuropneumoniae, Streptococcus suis, and Escherichia coli but was not active against Bordetella bronchiseptica measured by MIC . Based on pharmacokinetic studies of ceftiofur in swine after a single intramuscular injection of 3 or 5 mg/kg body weight of ceftiofur and on the MIC and disk diffusion data, we recommend MIC breakpoints and disk diffusion distances, respectively, of < or = 2 micrograms/ml and > or = 21 mm for susceptible, 4 micrograms/ml and 18-20 mm for intermediate, and > or = 8 micrograms/ml and > or = 17 mm for resistant classification for swine pathogens . When these breakpoints were applied to data from a previous study using bovine pathogens, only 1 minor interpretive error occurred.

J Vet Diagn Invest, 1996 Oct, 8(4), 455 - 9
Detection of toxigenic Pasteurella multocida infections in swine herds by assaying antibodies in sow colostrum; Levonen K et al.; Toxigenic Pasteurella multocida is the causative agent of progressive atrophic rhinitis (PAR), a serious respiratory infection of swine . Diagnosis of the disease has hitherto been based on clinical signs, pathologic findings, and subsequent isolation of the agent . The best Finnish pig breeding herds participating in the Finnish Pig Health Scheme have been surveyed for PAR since 1963, and the disease has been eradicated from these herds . In this study, a total of 5,650 colostrum samples from 188 Finnish Pig Health Scheme herds were analyzed with a new serologic screening method: an enzyme-linked immunosorbent assay (ELISA) able to detect antibodies to the toxin of P . multocida (PMT) . Although the herds had been continuously controlled for PAR, 1 herd with PMT antibodies was found . The positive reactions in the ELISA were confirmed by isolating the causative organism . The origin of the infection also appeared to be obvious . The serologic ELISA is a suitable method for the detection and screening of toxigenic P . multocida-infected pig herds.

J Comp Pathol, 1996 Oct, 115(3), 203 - 19
The relation of ventilatory failure to pulmonary, respiratory muscle and central nervous system disturbances in calves with an experimentally produced pneumonia; Desmecht DJ et al.; To explore the pathophysiology of respiratory failure in an experimental pneumonia, a Pasteurella haemolytica broth culture was injected intratracheally into 12 calves, which were then studied over a period of 10 h . Measurements were made of inspired minute ventilation (VE), ventilatory pattern {inspiratory time (TI), expiratory time (TE), respiratory rate (RR) and tidal volume (VT)}, transdiaphragmatic pressure (Pdi), occlusion pressure at the airway opening 100 milliseconds after onset of inspiration (Pawo100ms), arterial blood gas tensions and pH and recorded diaphragmatic electromyogram (EMGdi) and rectal temperature (Tr) . On and after the third hour after inoculation, the animals varied in respect of clinical signs, Tr, RR, VE, Pawo100ms/EMGdi, and arterial gases and pH . In benign cases, diminished alertness, laboured respiration and fall of arterial oxygen pressure (PaO2) worsened up to 7 h after inoculation, but then progressively improved, VE being maintained at approximately 150% baseline throughout the study (10 h) . Neither arterial carbon dioxide pressure (PaCO2) nor pH was altered . Moderate cases resembled benign cases in respect of laboured respiration, VE, PaO2 and PaCO2; however, pH was at first maintained at preinoculation levels, but declined thereafter . In severe cases, the animals were drowsy between hours 3 and 7, and became comatose between hours 8 and 10; in contrast to both benign and moderate cases: (1) RR was reduced by hour 5, (2) there was no trend towards recovery of PaO2 and pH, (3) VE, Pdi, Pawo100ms and Pawo100ms/EMGdi were severely decreased, and (4) PaCO2 increased . These results suggest that pneumonia does not alter ventilatory neuromuscular pump function in calves, unless concomitant cardiovascular collapse occurs . It is not clear whether fatal ventilatory failure is caused mainly by deterioration in ventilatory muscle fibre processes or structures, altered central nervous system adjustment of ventilatory timing, or cardiovascular dysfunction . However, inspiratory pressures fall when excitation to the diaphragm is still growing, which suggests peripheral respiratory muscle fatigue.

Microb Pathog, 1996 Oct, 21(4), 289 - 97
Influence of the capsular layer on the virulence of Pasteurella piscicida for fish; Magarinos B et al.; The influence of the capsule of Pasteurella piscicida on the cell surface properties of this microorganism as well as on the virulence and the capacity of the strains to grow in fish sera was examined . Although all the P . piscicida strains synthetized an additional exostructure in glucose-enriched-medium, only virulent strains constitutively synthetized capsule . The cell surface of all the P . piscicida isolates showed a low hydrophobic nature . No strains pelleted in broth culture (SP-) and all of them were stable after boiling (PAB) . All isolates attached to the fish cell line CHSE-214 with values of adherence ranging from 2 to 5% of the initial bacterial inoculum . The presence of induced capsular material caused changes in some cell surface characteristics such as hydrophobicity and stability after boiling . A decrease in the adherence capacity of all the P . piscicida strains was also observed . However, the capsule increased the degree of virulence for fish of the nonpathogenic strains (LD50 was reduced in about 4 log) and conferred to all the isolates resistance to serum killing . Therefore, these results indicate that the presence of capsule can play an important role in the pathogenesis of P . piscicida.

J Vet Pharmacol Ther, 1996 Oct, 19(5), 376 - 81
Penetration of parenterally administered ceftiofur into sterile vs . Pasteurella haemolytica-infected tissue chambers in cattle; Clarke CR et al.; The effect of bacterial infection on antibiotic activity and penetration of parenterally administered ceftiofur into implanted tissue chambers was studied in cattle . Tissue chambers were implanted subcutaneously in the paralumbar fossae of eight calves (256-290 kg body weight) . Approximately 80 days after implantation, the two chambers on one side of each animal were inoculated with Pasteurella haemolytica (10(6) CFU/chamber) . Eighteen hours after inoculation, ceftiofur sodium was administered intravenously (5 mg/kg) to each of the calves . Non-infected chamber fluid, infected chamber fluid and heparinized blood samples were collected immediately before and at 1, 3, 6, 12 and 24 h after drug administration . Concentrations of ceftiofur and desfuroylceftiofur metabolites and ceftiofur-equivalent microbiological activity were measured by high-pressure liquid chromatography and microbiological assay respectively . Concentrations of ceftiofur and desfuroylceftiofur metabolites and anti-microbial activity in P . haemolytica-infected tissue chambers were significantly higher than those in non-infected tissue chambers at all sampling times, indicating that ceftiofur, regardless of the method used for analysis, localizes at higher concentrations at tissue sites infected with P . haemolytica . Antibiotic activity-concentration ratios were lower in plasma and infected chamber fluid compared with non-infected chamber fluid, suggesting that antibiotic was bound to proteins . However, higher antimicrobial activity in the infected chamber fluid compared with the non-infected chamber fluid, suggests that active drug is reversibly bound to proteins . Protein-bound desfuroylceftiofur may represent a reservoir for release of active drug at the site of infection in the animal.

Can J Vet Res, 1996 Oct, 60(4), 263 - 70
In vitro lymphocyte proliferative responses and gamma-interferon production as measures of cell-mediated immunity of cattle exposed to Pasteurella haemolytica; DeBey BM et al.; Cell-mediated immune mechanisms may play a role in the pathogenesis and prevention of pneumonia in cattle caused by Pasteurella haemolytica serotype A1 . To determine the circumstances required to stimulate and identify cell-mediated immune responses, calves were vaccinated with a commercial P . haemolytica bacterin or a live commercial P . haemolytica vaccine, or were infected intratracheally with virulent P . haemolytica . All calves were challenge-exposed intratracheally with P . haemolytica 31 d after vaccination or prior infection . Peripheral blood mononuclear cells and mediastinal and superficial cervical lymph node cells were stimulated with antigens prepared from P . haemolytica to evaluate in vitro proliferative responses and gamma-interferon production as measures of cell-mediated immunity . Strong proliferative responses and gamma-interferon production were detected in lymph node cells from calves vaccinated with the live vaccine and from infected calves, especially in response to stimulation with an outer membrane protein preparation from P . haemolytica . Greater proliferative responses and gamma-interferon production were associated with the lymph node nearer the site of bacterin administration (superficial cervical lymph node) or the site of infection (mediastinal lymph node), whereas greater proliferative responses and gamma-interferon production were associated with the more distant lymph node (mediastinal lymph node) in calves vaccinated with the live vaccine . Neither proliferative responses nor gamma-interferon production were detected in peripheral blood mononuclear cells from calves that were vaccinated for or infected with P . haemolytica . Antileukotoxin antibody titers were determined by a serum neutralization assay, and protection against pneumonic lesions was more closely correlated with antileukotoxin antibody responses than with lymphocyte proliferation or gamma-interferon responses.

Am J Vet Res, 1996 Oct, 57(10), 1453 - 7
Antibody responses of cattle to outer membrane proteins of Pasteurella multocida A:3; Confer AW et al.; OBJECTIVE: To quantify the serum antibody responses to Pasteurella multocida A:3 outer membrane proteins (OMP) for cattle vaccinated with the homologous serogroup and to correlate those responses with the extent of experimentally induced pneumonia . ANIMALS: 29, 5- to 8-month-old beef-type calves . PROCEDURE: Calves were vaccinated SC or by aerosal exposure on days 0 and 7 with live or killed P multocida or phosphate-buffered saline solution (control) and subsequently challenge exposed with virulent P multocida . Antibody responses to P multocida A:3 outer membranes were quantified, using an ELISA . Antibody responses to individual OMP were detected by immunoblot analysis (western blot) and were quantified by densitometry . Antibody responses were compared among groups of calves and for various times after vaccination . Regression analyses were used to determine whether significant correlations existed between lesion scores and antibody responses to either whole outer membranes or to individual OMP . RESULTS: By ELISA, antibody responses to outer membranes for calves aerosol vaccinated with live P multocida were significantly (P < 0.05) greater than those for control calves or for killed P multocida vaccinates . There was a significant (P < 0.05) correlation between lesion score and antibody responses to outer membranes . By western blotting and densitometry, antibodies to 11 prominent OMP (100, 97, 90, 85, 74, 53, 46, 35, 32, 21, and 16 kd) were identified and quantified . In experiment 1, SC vaccination with live P multocida increased antibody binding to all protein bands except 85-, 74-, and 35-kd bands . Aerosol vaccination with live P multocida stimulated increases in antibody binding to all bands except 100 and 16 kd . Antibody responses to the 97-, 90-, 74-, and 35- kd bands were significantly (P < 0.05; greater for live aerosol vaccinates than for control calves . In experiment 2, antibody responses were not different between the killed P multocida vaccinates or control calves Antibody responses for live P multocida aerosol vaccinates were significantly (P < 0.05) greater than those for control calves for the 100-, 90-, 85-, 74-, 53-, 35-, and 16-kd bands . Regression analyses indicated significant correlations (P < 0.05) between lesion score and antibody responses to the 100-, 90-, 53-, 46-, 35-, and 32-kd OMP . CONCLUSIONS: Several OMP of P multocida type A:3 may be important for stimulating immunity to the organism in cattle.

J Rheumatol, 1996 Oct, 23(10), 1824 - 5
Pasteurella multocida arthritis of the shoulder associated with postsurgical lymphedema; Fellows L et al.; We describe a patient with postsurgical lymphedema and septic arthritis of the shoulder after a cat bite distally . Our case illustrates the importance of a high index of suspicion for infection in patients with shoulder pain and pre-existing edema.

Poult Sci, 1996 Oct, 75(10), 1180 - 91
Direct and correlated responses to long-term selection for increased body weight and egg production in turkeys; Nestor KE et al.; Lines of turkeys were selected long-term for increased egg production (E line; 34 generations) or increased 16-wk BW (F line; 28 generations) . The E and F lines were started from randombred control populations (RBC1 and RBC2, respectively) that were also maintained to remove environmental variation among generations . Realized heritabilities (h2) +/- SE in the E line, based on regressions of response on cumulated actual selection differentials (selection differentials weighted for the number of offspring produced), for 180-d and 250-d egg production were 0.34 +/- 0.02 (17 generations) and 0.26 +/- 0.13 (8 generations), respectively . The realized h2 of 16-wk BW in the F line was 0.26 +/- 0.01 . There was no consistent evidence of selection response reaching a plateau in either line . The genetic association of BW and egg production changed with selection in the E and F lines . The genetic correlation varied from near zero to strongly negative and fluctuated between these extremes in both lines even though they started from different base populations and selection criteria differed . Other correlated responses to selection for increased egg production were increased average clutch length (intensity of lay), and decreased broodiness (total days lost), egg weight, shell coloration, and rate of response to stimulatory lighting . Other correlated responses to selection for increased 16-wk BW in the F line included: increased egg weight (due to increased albumen), longer eating bouts, and decreased average clutch length, semen production, walking ability, and resistance to Pasteurella multocida and Newcastle disease virus . Selection within the E and F lines also changed the frequency of MHC haplotypes and the changes appeared to be in opposite directions in the two lines.

Poult Sci, 1996 Oct, 75(10), 1161 - 3
Influence of growth selection in turkeys on resistance to Pasteurella multocida; Nestor KE et al.; Four lines of turkeys, a randombred control (RBC2) started in 1966 and three sire lines (F, A, and B), were challenged with a field isolate of Pasteurella multocida (capsular serogroup A, somatic serotype 3, 4) at 6 wk of age . Line F, a subline of the RBC2 line, was selected for 28 generations for increased 16-wk BW and Lines A and B were primary breeding sire lines from two commercial breeders . Each bird was inoculated subcutaneously in the back of the neck with 1.2 x 10(7) washed bacteria . Mortality following challenge with P . multocida was higher in the sire lines (54 to 65%) than in the RBC2 line (26%) . There was no significant difference in mortality among sire lines following challenge . These results suggest that the increased susceptibility to P . multocida in the F line in comparison to its control may be due to genetic changes resulting from selection for increased BW in this line.

Int J Syst Bacteriol, 1996 Oct, 46(4), 951 - 6
Actinobacillus minor sp . nov., Actinobacillus porcinus sp . nov., and Actinobacillus indolicus sp . nov., three new V factor-dependent species from the respiratory tract of pigs; Moller K et al.; The results of DNA-DNA relatedness experiments and comparisons of sequences of genes coding for 16S rRNA were used to determine the genetic relationships of selected V factor-dependent species belonging to the family Pasteurellaceae and obtained from the porcine respiratory tract . These results showed that the Minor group and taxa C, D plus E, and F are distinct phylogenetic groups that are separate from each other and from other members of the family Pasteurellaceae . On the basis of these results, three new species, corresponding to the Minor group, taxa D plus E, and taxon F, are proposed; the names of these new species are Actinobacillus minor (type strain, NM305), Actinobacillus porcinus (type strain, NM319), and Actinobacillus indolicus (type strain, 46KC2), respectively.

J Acquir Immune Defic Syndr Hum Retrovirol, 1996 Oct 1, 13(2), 101 - 16
Myopathy and spontaneous Pasteurella pneumotropica-induced abscess formation in an HIV-1 transgenic mouse model; Dickie P et al.; In an effort to augment human immunodeficiency virus type 1 (HIV-1) gene expression in transgenic mice, an infectious proviral DNA clone was modified by deleting the two NF kappa B binding sites and some adjacent upstream LTR sequences and replacing them with the core enhancer of Moloney murine leukemia virus (MLV) . Two independent lines of MLV/HIV transgenic mice were established that expressed HIV-1-specific RNA in lymphoid tissue, striated skeletal muscle, and the eye lens . Heterozygous animals from each transgenic line spontaneously developed an inflammatory disease of the eye associated with the production of copious amounts of purulent lacrimal secretions beginning at 2 weeks of age . Periorbital abscess formation became grossly apparent by 2 months of age and Pasteurella pneumotropica was cultured from the harderian glands and conjunctival surfaces of many of the MLV/HIV animals but not their nontransgenic, cohabiting littermates . This gram-negative commensal bacterium has been previously associated with a similar disease phenotype in immunocompromised (e.g., nude mice) rodent colonies . MLV/HIV mice developed normally until 15 weeks of age, when weight loss and wasting occurred, culminating in premature death (as earlier as 6 months of age) . The cachexia was associated with an initially focal and subsequently progressive myopathy, coinciding with age-related increases of HIV gene expression in muscle.

Curr Microbiol, 1996 Oct, 33(4), 266 - 9
In vivo production of neuraminidase by Pasteurella multocida A:3 in goats after transthoracic challenge; Straus DC et al.; Six goats were injected transthoracically with live Pasteurella multocida A:3 to examine if an extracellular enzyme, neuraminidase, was produced in vivo during infection with this organism . The principal group of goats (n = 6) each received 1 ml of live 7.5 x 10(4) cfu of P . multocida mixed with polyacrylate beads transthoracically in the left lung on day 0 and 1 ml of live P . multocida (2.2 x 10(8) cfu) mixed with polyacrylate beads transthoracically in the left lung on day 22 . Six goats were used as negative controls and received 0.3 g of polyacrylate beads subcutaneously in the right flank on days 0 and 22 . Serum was obtained from all animals on days 0, 7, 14, 22, 29, and 36 . Preimmune sera from all animals showed no detectable antibody to P . multocida A:3 neuraminidase in an enzyme neutralization assay . None of the sera from the negative control animals demonstrated a significant antibody titer against the P . multocida A:3 neuraminidase . On day 36, serum samples from the six infected animals possessed complete enzyme-neutralizing activity . Anti-neuraminidase antibody could be detected as early as day 14 in the infected animals . These data show that neuraminidase is produced in vivo during an active P . multocida A:3 lobar infection.

FEMS Microbiol Lett, 1996 Sep 15, 143(1), 97 - 101
Vacuolating cytotoxic activity of Pasteurella multocida causing haemorrhagic septicaemia in buffalo and cattle; Shah NH et al.; The toxic activity of Pasteurella multocida strains which cause haemorrhagic septicaemia (HS) in buffalo and cattle was examined in a mouse model . Mice were injected intraperitoneally with 10(2) cells of P . multocida serotype B:2,5 . Electron microscopy of peritoneal macrophages obtained 6 h after injection revealed strong induction of cytoplasmic vacuolation, macrophage lysis and death . In vitro experiments with the mouse macrophage cell line RAW 264 incubated with cultures of various HS- and non-HS-associated strains of P . multocida or with culture supernatants revealed macrophage vacuolation when HS-associated strains were used . On pre-incubation of the strains with antiserum obtained from buffalo infected with P . multocida serotype B:2,5 no vacuolation was observed . These results are indicative of the presence of vacuolating cytotoxic activity in HS-associated strains of P . multocida.

Vet Microbiol, 1996 Sep, 52(1-2), 91 - 102
Validation of random amplified polymorphic DNA assays by ribotyping as tools for epidemiological surveys of Pasteurella from animals; Chaslus-Dancla E et al.; Two collections of strains of Pasteurella were studied for epidemiological purposes by ribotyping and random amplified polymorphic DNA (RAPD) assays . These strains were isolated through two different structures of animal productions: cattle and rabbit . Forty strains of P . haemolytica from cattle reared in independent breeding-herds belonged to only 3 ribotypes after digestion with HindIII and PvuII . No further discrimination of these strains was obtained by RAPD assays . All these 40 strains showed more than 90% of similarity . This result was consistent with the hypothesis of a clonal dissemination of these strains in bovine herds, possible favoured by the large use of antibiotics . Forty-one strains of P . multocida were isolated in rabbits flocks belonging to 16 breeders . Six of these were linked by commercial relationships . Twenty-eight out of the 29 strains isolated through this commercial network belonged to only three ribotypes whereas the 12 strains from independant breeders belonged to 9 ribotypes . Results of RAPD assays were in accordance with those of ribotyping and validate the use of RAPD assays for epidemiological studies of Pasteurella strains.

Vet Q, 1996 Sep, 18(3), 100 - 1
An epidemiological study into risk indicators for Pasteurella haemolytica related 'summer pneumonia' in lambs in the southern Netherlands; Dercksen DP et al.; Risk indicators for Pasteurella haemolytica related summer pneumonia in lambs in The Netherlands were investigated using a mail questionnaire survey of 860 flocks . The response rate was 64% (n = 550) . Multivariate risk analysis indicated that taking sheep to sheep fairs, the purchase of sheep and/or lambs, the lack of possibility for indoor housing, and an increased flock size were associated with increased risk of occurrence of summer pneumonia in lambs of the home flock.

Yeast, 1996 Sep, 12(10B Suppl), 1077 - 84
The sequence of a 20.3 kb DNA fragment from the left arm of Saccharomyces cerevisiae chromosome IV contains the KIN28, MSS2, PHO2, POL3 and DUN1 genes, and six new open reading frames; Saiz JE et al.; We report the sequence of a 20 300 bp DNA fragment from the left arm of Saccharomyces cerevisiae chromosome IV . This segment contains 13 complete open reading frames (ORFs) and part of another ORF, altogether covering 84.2% of the entire sequence, five of which correspond to the previously characterized KIN28, MSS2, PHO2, POL3/CDC2 and DUN1 genes . One putative protein, D2358p, shares considerable homology with an O-sialoglycoprotein endopeptidase from Pasteurella haemolytica serotype A1 . The putative product of D2325 contains the characteristic consensus motif of triacylglycerol lipases . D2320p and D2352p have a putative 'leucine-zipper' structure and a RNA-binding region Rnp-1 signature, respectively.

Zentralbl Veterinarmed B, 1996 Sep, 43(7), 429 - 38
An immunohistochemical method of detecting Mycoplasma species antigens by use of monoclonal antibodies on paraffin sections of pneumonic bovine and caprine lungs; Rodriguez F et al.; Lung samples from pneumonic lesions in cattle and goats, naturally or experimentally infected with strains of the Mycoplasma mycoides cluster, were fixed in formalin and embedded in paraffin . An immunohistochemical technique using monoclonal or polyclonal antibodies was performed on tissue sections in order to detect Mycoplasma antigens . Four monoclonal antibodies (MAbs), one (2A3) raised against M . mycoides ssp . mycoides small colony (SC) and large colony (LC), two (1D3 and 5E5) against M . mycoides ssp . capri, and one (5A10) against M . bovis, were used . A range of polyclonal antibodies, raised to the individual subspecies of the M . mycoides cluster, and one to Pasteurella haemolytica, was also used . The MAb 2A3 showed positive immunostaining in lung sections from cattle and goats naturally and experimentally infected with M . mycoides ssp . mycoides SC and LC, but not with pneumonic lesions of cattle and goats due to other members of the M . mycoides cluster, M . bovis or Pasteurella spp . The MAb 1D3 showed immunostaining in lung sections from goats naturally and experimentally infected with M . mycoides ssp . capri, but again not with pneumonic lesions caused by other members of the M . mycoides cluster, M . bovis or Pasteurella spp . The MAb 5E5 immunoreacted in sections from pneumonic lesions from all animals infected with one of the three M . mycoides cluster subspecies used in the study, but not with M . bovis or Pasteurella infected tissue . Immunoreaction was mainly found in the cell debris around necrotic areas, as well as in macrophages, neutrophils and epithelial cells . The localization of antigens of the M . mycoides cluster using polyclonal antisera followed basically the same pattern as that obtained with the monoclonals . However, a wide cross reactivity was found between different antisera and relatively high background immunostaining was also seen, especially in necrotic areas . The results suggest that immunohistochemical methods using monoclonal antibodies are useful tools for the diagnosis and study of the pathogenesis of pneumonia caused by the Mycoplasmas of the M . mycoides cluster.

Am J Vet Res, 1996 Sep, 57(9), 1317 - 20
Respiratory tract disease and mucosal colonization by Pasteurella haemolytica in transported cattle; Frank GH et al.; OBJECTIVES: To follow incidence of Pasteurella haemolytica (PH) in the upper respiratory tract of healthy calves at the farm and through the marketing process, and to determine the effect of vaccination on PH colonization of the upper respiratory tract and on the incidence of respiratory tract disease (RTD) . ANIMALS: 2- to 5-month-old calves (n = 104) from 4 farms . PROCEDURE: Calves were vaccinated with a killed PH serotype-1 product . Nasal secretion and tonsil wash specimens were cultured for PH, and serum antibody was measured by indirect hemagglutination . Calves with RTD were treated with tilmicosin phosphate . RESULTS: At the feedyard, 73 calves had RTD . The incidence of RTD was significantly related to the farm of origin, and was inversely related to the PH serum titer at the farm, but was not influenced by vaccination . Isolations of PH serotype 1, however, were reduced by vaccination . The major serotypes of PH encountered were 1 and 6 . CONCLUSION: Vaccination can reduce the frequency of colonization of the upper respiratory tract by PH.

J Clin Microbiol, 1996 Sep, 34(9), 2185 - 90
Synergistic role of gaseous ammonia in etiology of Pasteurella multocida-induced atrophic rhinitis in swine; Hamilton TD et al.; One-week-old Large White piglets were weaned and allocated to 14 experimental groups, each composed of five animals . Each group was housed in a separate Rochester exposure chamber and exposed continuously to gaseous ammonia at either 0, 5, 10, 15, 25, 35, or 50 ppm (two groups per exposure level) . One week after ammonia exposure commenced, the pigs from one group at each exposure level were inoculated intranasally with 9 x 10(7) CFU of Pasteurella multocida type D . After a further 4 weeks of exposure, all the pigs were euthanized and the extent of turbinate degeneration was assessed by using a morphometric index (J.T . Done, D . H . Upcott, D . C . Frewin, and C . N . Hebert, Vet . Rec . 114:33-35, 1984) and a subjective scoring system (Ministry of Agriculture, Fisheries and Food, Atrophic Rhinitis: a System of Snout Grading, 1978) . Exposure to ammonia at a concentration of 5 ppm or greater resulted in a significant increase in the severity of turbinate atrophy induced by P . multocida compared with that occurring in pigs kept in 0 ppm of ammonia . This effect was maximal at 10 ppm but decreased progressively at concentrations above 25 ppm . Regression analysis revealed a significant relationship between the severity of turbinate degeneration and the number of P . multocida organisms isolated from the nasal epithelium at the end of the experiment (R2 = 0.86) . These findings suggest that exposure to ammonia facilitates the growth and/or survival of P . multocida within the upper respiratory tract of the pig, thereby contributing to the severity of the clinical disease atrophic rhinitis . Furthermore, exposure of pigs to ammonia at 10 ppm or greater, in the absence of either P . multocida or Bordetella bronchiseptica, induced a mild but statistically significant degree of turbinate atrophy . The findings of this study demonstrate that exposure to ammonia, at concentrations within the range encountered commonly in commercial piggeries, contributes to the severity of clinical lesions associated with atrophic rhinitis.

Microbiology, 1996 Sep, 142 ( Pt 9), 2499 - 507
Characterization of epitopes involved in the neutralization of Pasteurella haemolytica serotype A1 leukotoxin; Lainson FA et al.; Defined segments of the leukotoxin A gene (lktA) from an A1 serotype of Pasteurella haemolytica were cloned into a plasmid vector and expressed as LacZ alpha fusion proteins . These fusion proteins were electrophoresed in SDS-PAGE gels and their immunoblotting reactivities with several monoclonal antibodies characterized . The epitope recognized by a strongly neutralizing monoclonal antibody was localized to a 32 amino acid region near the C terminus of the leukotoxin A (LktA) molecule . The epitope recognized by a non-neutralizing antibody was localized to a 33 amino acid region immediately adjacent . Smaller recombinant peptides containing these epitopes were not antigenic, but a polypeptide encompassing 229 amino acids at the C terminus evoked neutralizing antibodies when used to immunize specific-pathogen-free lambs . The distributions of linear epitopes recognized by this antiserum and by antisera raised to full-length recombinant LktA and to native LktA produced by P . haemolytica serotype A1 were determined by their reactivities with a set of overlapping 10 amino acid synthetic peptides . This revealed a complex distribution of linear epitopes at the C-terminal end of LktA . Toxin-neutralizing antibodies in convalescent sheep serum were shown to be directed against conformational epitopes by selective absorption of antibodies directed against linear epitopes.

Br J Haematol, 1996 Sep, 94(4), 597 - 605
Differences in the distribution of CD34 epitopes on normal haemopoietic progenitor cells and leukaemic blast cells; Steen R et al.; The CD34 molecule expressed on haemopoietic progenitor cells contains a large number of epitopes whose expression may be related to the maturation or function of the cells . Monoclonal antibodies specific for different epitopes have been reported to detect different numbers of CD34+ leukaemic blast cells . We wanted to confirm this observation and study whether parallel findings could be observed for normal haemopoietic progenitor cells . The cells were immunophenotyped by flow cytometry with a series of monoclonal antibodies reactive with different CD34 epitopes . Class III epitopes (resistant to enzymatic cleavage with neuraminidase, chymopapain and a glycoprotease from Pasteurella haemolytica) showed a broader distribution on normal haemopoietic progenitor cells and leukaemic blast cells than class I epitopes (sensitive to cleavage with all three enzymes) and class II epitopes (sensitive to degradation with glycoprotease and chymopapain, and resistant to neuraminidase) . The subpopulation of normal progenitor cells which exclusively expressed class III epitopes had flow cytometric characteristics compatible with mature myeloid progenitor cells whereas class I, II and III epitopes were equally expressed on cells enriched for immature subsets . No discordant epitope expression could be observed for the more immature leukaemias (AML-M0/1) and a higher percentage of the more mature leukaemic blast cells (AML-M3 and AML-M4/5) expressed class III epitopes compared to the percentage expressing class I and II epitopes . These data indicate that CD34 class III epitopes are more broadly distributed on normal haemopoietic progenitor cells and leukaemic blast cells than class I and II epitopes, and that class I and II epitopes may be down-regulated prior to class III epitopes during normal haemopoietic progenitor cell differentiation . These findings should be considered when selecting CD34 mabs for quantification and positive selection of haemopoietic progenitor cells for research and clinical purposes.

Lett Appl Microbiol, 1996 Aug, 23(2), 101 - 3
Detection of bacterial antigens using immuno-PCR; Kakizaki E et al.; A new and very sensitive antigen detection technique, immuno-polymerase chain reaction (immuno-PCR), was developed . This method is basically similar to the enzyme-linked immunosorbent assay which detects an antigen-antibody reaction, but instead of an enzyme being conjugated to an antibody, a DNA fragment is used and this DNA can be amplified by PCR . We applied this method to the detection of the fish pathogen, Pasteurella piscicida, in naturally infected yellowtail . Using immuno-PCR, 3.4 cfu ml-1 of bacteria could be detected . In comparison, ELISA detected only 3.4 x 10(4) cfu ml-1 . Immuno-PCR is a powerful method for detection of pathogens in host tissues.

J Vet Med Sci, 1996 Aug, 58(8), 781 - 2
The fractional inhibitory concentration index of antimicrobial agents for bacteria and Mycoplasma isolated from the nasal swabs of cattle with respiratory diseases; Katoh T et al.; We investigated the effect of thiamphenicol plus lincomycin (TP + LCM) and thiamphenicol plus tylosin (TP + TS) combinations using checker board method on the growth of Pasteurella (P.) multocida, P . haemolytica and Mycoplasma (M.) bovis by calculating the fractional inhibitory concentration index (FIC index) . The results showed that the FIC indexes of the TP + LCM combination for P . multocida, P . haemolytica and M . bovis were 0.36 +/- 0.10, 0.72 +/- 0.09 and 0.81 +/- 0.18, respectively . The FIC indexes of the TP + TS combination for P . multocida, P . haemolytica, and M . bovis were 0.79 +/- 0.20, 0.66 +/- 0.11 and 0.32 +/- 0.14, respectively . Thus, these combinations are assumed to have a more synergistic or additive effect on bacteria growth than a single antimicrobial agent.

J Antimicrob Chemother, 1996 Aug, 38(2), 205 - 13
CAT III chloramphenicol resistance in Pasteurella haemolytica and Pasteurella multocida isolated from calves; Vassort-Bruneau C et al.; Chloramphenicol, which had been used extensively for antimicrobial veterinary therapy, was prohibited in Europe in 1994 . Soon after it became available, resistance to this drug was detected, generally conferred by plasmids encoding inactivating enzymes, the chloramphenicol acetyltransferases (CAT), in Gram-negative as well as in Gram-positive bacteria . In the last few years, resistance to antibiotics emerged in Pasteurella strains from breeding herds and this evolution was followed by a national surveillance network . Chloramphenicol-resistance was more recently detected in multiresistant strains . We studied 25 strains of Pasteurella, selected for their resistance to chloramphenicol . Production of a CAT was demonstrated in all these strains . PCR amplification indicated that the CAT produced was of type III for 23 of them . In these strains, chloramphenicol-resistance was mediated by plasmids of about 5.1 kb . Southern blots on restriction fragments suggested a high degree of homology between these 5.1 kb plasmids . In the two other strains, production of a CAT type I was demonstrated, and the corresponding genes were either shown on a plasmid of 17 or 5.5 kb.

Lab Anim Sci, 1996 Aug, 46(4), 386 - 92
Randomly amplified polymorphic DNA polymerase chain reaction assay for molecular epidemiologic investigation of Pasteurella pneumotropica in laboratory rodent colonies; Weigler BJ et al.; After an episode of clinical Pasteurella pneumotropica infection was diagnosed in a C57BL/6N mouse, a randomly amplified polymorphic DNA polymerase chain reaction assay (RAPD-PCR) was developed and used to genetically characterize and differentiate 52 field isolates and laboratory reference strains of P . pneumotropica and related bacteria . A survey of rodents in the facility recovered 36 isolates of P . pneumotropica from 30 mice, six isolates from hamsters, and three isolates from rats during the follow-up investigation . Antibiograms and routine bacteriologic evaluations for morphologic and biochemical characteristics on selective media did not substantively aid in the differentiation of these isolates, but the RAPD-PCR revealed four strains of P . pneumotropica in the colony, two of which were confined to rats and hamsters . The RAPD-PCR unambiguously differentiated Heyl and Jawetz biotypes of P . pneumotropica recovered from mice, identified two additional genetic groups for rat and hamster isolates, and clearly distinguished P . pneumotropica from related bacteria . Most field isolates were genetically consistent with the Jawetz biotype of P . pneumotropica . The RAPD-PCR is a fast, sensitive, and efficient method for identifying genetic differences between strains of the P . pneumotropica complex and can contribute substantially in addressing the epidemiology, pathogenesis, and taxonomic classification of this common opportunistic pathogen.

Vet Microbiol, 1996 Aug, 51(3-4), 381 - 91
The isolation of recombinant plasmids expressing secreted antigens of Pasteurella haemolytica A1 and the characterization of an immunogenic 60 kDa antigen; Lo RY et al.; A collection of recombinant plasmids had been isolated which express secreted antigens of Pasteurella haemolytica A1 likely to be important in protection . The recombinant Escherichia coli clones were found to express the P . haemolytica A1 antigens by Western immunoblot analysis, using sera from calves which had been vaccinated with Presponse and were subsequently resistant to experimental challenge with P . haemolytica A1 . Detailed analysis of three of the recombinant plasmids (pGS1-17, pGS3-19 and pSA1-50) showed that they all carry the same 4.2 kbp insert DNA . E . coli clones which carry the recombinant plasmids all express a strongly antigenic protein of approximately 60 kDa . Nucleotide sequence analysis of the cloned DNA showed that it codes for a polypeptide with an estimated M.W . of 60.8 kDa . A partial clone of this gene has been reported previously and an antibody response to the antigen was shown to be significantly correlated to resistance to disease . This gene was found to be present in only the A biotypes of P . haemolytica and not in the T biotypes, which have been reclassified Pasteurella trehalosi . This demonstrates that this recombinant plasmid collection codes for antigens of P . haemolytica A1 important to protection and warrants further characterization to identify additional recombinant antigens.

Vet Microbiol, 1996 Aug, 51(3-4), 331 - 41
Genetic and immunological analyses of a 38 kDa surface-exposed lipoprotein of Pasteurella haemolytica A1; Pandher K et al.; Pasteurella haemolytica serotype A1 is the bacterial pathogen most frequently isolated from the lungs of cattle with bovine respiratory disease . As part of a study to characterize P . haemolytica antigens which are important in eliciting resistance to pneumonic pasteurellosis, we have cloned and sequenced the gene encoding a 38 kDa lipoprotein, Lpp38 . The deduced amino acid sequence of Lpp38 is similar to those of the Escherichia coli polyamine transport proteins PotD (70%) and PotF (33%) . P . haemolytica Lpp38 is present in both inner membrane and outer membrane fractions of the cell envelope . Susceptibility of Lpp38 to cleavage by extracellular proteases indicates that portions of the protein are surface-exposed . A protein of similar molecular mass in P . haemolytica strains from all 12 serotypes of biotype A and in an untypeable strain was detected by an anti-Lpp38 monoclonal antibody . Lpp38 is recognized by sera from calves resistant to infection after natural exposure to P . haemolytica and by sera from calves protected against infection by vaccination with P . haemolytica A1 outer membranes or with live bacteria . These data suggest a role for this protein in the development of immunity to P . haemolytica infection.

Vet Microbiol, 1996 Aug, 51(3-4), 319 - 30
Major outer membrane proteins of Pasteurella haemolytica serovars 1-15: comparison of separation techniques and surface-exposed proteins on selected serovars; Morton RJ et al.; The Sarkosyl method of obtaining outer membrane proteins (OMPs) from Pasteurella haemolytica A1 was more efficient and less laborious than separating membranes by sucrose gradient centrifugation . More OMPs were recovered and major OMPs were present in greater concentrations in the Sarkosyl-derived preparations . Therefore, OMPs of P . haemolytica serovars 1-15 (serovars 3, 4, 10, and 15 being T biotypes and the remainder being A biotypes) were prepared by the Sarkosyl method and compared by SDS-PAGE . Serovars 1, 2, 5, 6, 7, 8, 11, and 12 which are A biovars had similar OMP profiles characterized by major OMPs of 30.5 and 43 kDa . Biovar T strains were characterized by doublet protein bands in the 26-28 kDa region and a major OMP in the 38-40 kDa range . Serovars 9, 13, and 14, which are also A biovars, had profiles similar, although not identical, to the T biovars . A 43 kDa protein was present in all serovars although concentration was greater in the A biovars . Surface-exposed proteins of P . haemolytica A1 determined by 125I-labeling of whole cells were 94, 84, 53.5, 49, 43, 41, 29.5, and 16 kDa . Iodine-labeling of serovars A2 and A6 which have similar OMP profiles by SDS-PAGE resulted in autoradiographs indistinguishable from A1 . These studies expand our knowledge of P . haemolytica OMPs especially showing the utility of the Sarkosyl extraction procedure, variations in OMP profiles among some A biovar strains, and the similarities of OMP profiles and surface-labeled proteins among three of the most important serovars (1, 2, and 6).

Am J Vet Res, 1996 Aug, 57(8), 1180 - 4
Use of tilmicosin for treatment of pasteurellosis in rabbits; McKay SG et al.; OBJECTIVES: To determine tilmicosin concentrations in serum and tissues of rabbits given a single dose of 25 mg of tilmicosin/kg of body weight . To examine the effects of tilmicosin treatment (25 mg/kg, s.c.) in rabbits with pasteurellosis . PROCEDURE: After receipt of tilmicosin, healthy New Zealand White female rabbits (n = 3 at each time) were euthanatized at 2, 4, 8, 24, 48, and 72 hours for collection of blood samples and tissue specimens; 4 rabbits served as untreated controls . Rabbits (male and female) with pasteurellosis (n = 42) also were treated . Tilmicosin concentration was determined in serum, lung, and uterine tissues . Rabbits with pasteurellosis were treated with tilmicosin . Response was monitored, using bacteriologic culturing and antibiotic resistance and susceptibility testing, and by scoring clinical signs of disease . RESULTS: Serum tilmicosin concentration reached 1.91 +/- 0.18 micrograms/ml after 2 hours, decreased to 0.77 +/- 0.07 microgram/ml by 8 hours, and was below minimum inhibitory concentrations for Pasteurella multocida at 24 hours . Terminal half-life in serum was 5.97 hours . Lung and uterus concentrations were 14.43 +/- 1.34 and 11.57 +/- 0.09 ppm at 2 hours, and were 5.10 +/- 1.05 and 8.87 +/- 1.66 ppm at 24 hours, respectively . 69% (29/42) of rabbits with pasteurellosis responded favorably in 3 days . Second treatment was required in 31% (13/42), and 5 of these rabbits had clinical signs on day 6; 2 of these 5 had improved . Treatment success rate was 93% (39/42) . Of the rabbits that were culture positive on day 0, 35% (6/ 17) remained positive on day 3 . 1 of 6 rabbits was culture positive on day 6 . CONCLUSION: Tilmicosin (25 mg/kg, s.c.) was an effective treatment for pasteurellosis in New Zealand White rabbits . CLINICAL RELEVANCE: Tilmicosin treatment of pasteurellosis in rabbits is useful in research rabbits and in those destined for meat production . A single dose of antibiotic minimizes stress-associated handling.

Am J Vet Res, 1996 Aug, 57(8), 1168 - 74
Efficacy of a subcutaneously administered, ultraviolet light-killed Pasteurella haemolytica A1-containing vaccine against transthoracic challenge exposure in goats; Purdy CW et al.; OBJECTIVE: To determine the effectiveness of Pasteurella haemolytica biovar A, serovar 1 (Ph A1) killed by UV light and incorporated with an oil adjuvant or carriers . ANIMALS: 40 weaning male Spanish goats . PROCEDURE: Goats were randomly allotted to 1 of 6 treatment groups: 4 Ph A1 bacterins (agar beads, polyacrylate beads {PA}, phosphate-buffered saline solution, Freund's incomplete adjuvant), live Ph A1 with polyacrylate beads (LiPhPA), and polyacrylate beads (UnVac) . Each of 4 Ph A1 vaccines was administered SC twice, 21 days apart, to 1 of 4 groups; another group received only PA beads SC, and the last group received live Ph A1 with PA beads by transthoracic injection into the left lung . 14 days after the second vaccination, all goats were challenge exposed with live Ph A1 by transthoracic injection into the right lung, and 4 days later, all goats were euthanatized and necropsied . RESULTS: Mean volume of consolidated right lung tissue was 1.02 cm3 for the LiPhPA group, 168.1 cm3 for the UnVac group, 2.3 cm3 for the Freund's incomplete adjuvant bacterin group, 5.53 cm3 for the PA bacterin group, 9.01 cm3 for the agar beads bacterin group, and 7.51 cm3 for the phosphate-buffered saline solution bacterin group . Mean volume of consolidated lung tissue was significantly different between the UnVac group and the other 5 groups . CONCLUSION: The LiPhPA group and 4 bacterin groups developed protective immunity against live Ph A1 challenge exposure . CLINICAL RELEVANCE: An s.c . administered, UV light-killed Ph A1 bacterin induced protective immunity equal to that induced by virulent live Ph A1 injected into the target organ, the lung.

Poult Sci, 1996 Aug, 75(8), 991 - 7
Examination of the dietary methionine requirements of breeding northern bobwhite, Colinus virginianus; Dabbert CB et al.; Adult Northern bobwhite were used to test the hypothesis that dietary methionine levels recommended by the NRC for breeding quail are excessive for wild bobwhite . We tested the hypothesis by comparing immunocompetence, reproductive performance, and chick viability of Northern bobwhite hens fed diets containing low (0.31%), moderate (0.39%), or high (0.47%) concentrations of methionine . Chick viability was determined by assessing immunocompetence, including evaluating the ability of hens to passively transfer immunity to their chicks . Hens were fed the experimental diets for 6 wk on an ad libitum basis . After 6 wk, methionine treatment had no measurable effect (P > or = 0.20) on hen phytohemagglutinin wing web indices, organ weights, or serum anti-Pasteurella multocida titer indices . Mean egg weight, percentage egg production, total cumulative egg production, yolk weight, yolk volume, and percentage fertile and percentage hatch of fertile eggs did not differ (P > or = 0.12) among diet treatments . Amount of albumen in eggs produced by hens fed the high methionine diet averaged 0.27 g more (P = 0.003) than eggs of hens fed the low methionine diet . Anti-P . multocida titer of yolks from eggs in Week 6 were not different (P = 0.36) between birds fed the high and the low methionine diets . The mortality rate of chicks after challenge with 23 cfu of P . multocida was not different (P > or = 0.05) among diets . Chicks hatched from eggs laid by vaccinated hens during Weeks 2 and 3, however, had lower (P < 0.05) mortality than chicks of unvaccinated hens . It appears a dietary methionine concentration of 0.3% may be sufficient for wild Northern bobwhite to produce viable chicks.

FEMS Microbiol Lett, 1996 Aug 1, 141(2-3), 189 - 93
Constitutive expression of Pasteurella multocida toxin; Hoskins IC et al.; The expression of the Pasteurella multocida toxin (PMT) gene toxA was investigated . Growth in vitro at 30 degrees C or added iron caused less than 4-fold repression of toxA expression . The putative repressor TxaR was expressed in Escherichia coli but deletion and frameshift mutations abolishing TxaR production had no effect on toxA expression . Naturally occurring non-toxigenic mutants which contained the toxA gene had no large rearrangements near toxA or changes in toxA promoter structure . Thus PMT is constitutively expressed and is only regulated in a minor way.

Infect Immun, 1996 Aug, 64(8), 3081 - 7
Escherichia coli hemolysin mutants with altered target cell specificity; Pellett S et al.; In order to understand the functional significance of HlyC-dependent acylation of the Escherichia coli hemolysin structural protein (HlyA), random as well as site-directed substitutions at the known regions of modification, i.e., those at lysine residues at amino acid positions 563 and 689 (HlyAK563 and HlyAK689, respectively), were isolated . Sixteen random hlyA mutations were identified on the basis of a screen for loss of immunoreactivity to the hemolysin-neutralizing D12 monoclonal antibody that reacts to only HlyC-activated HlyA . These substitutions occurred at the region from HlyAE684 to HlyAY696 . A recombinant glutathione S-transferase-hemolysin gene fusion encoding glutathione S-transferase-HlyAS608-T725 residues reacts with monoclonal antibody when HlyC is coexpressed with the fusion protein . Therefore, at most only 12% of the total HlyA primary sequence is needed for HlyC-facilitated acylation at the HlyAK689 position, and this modification can occur in the absence of the proximal HlyAK563 acylation site . The cytolytic activities of these HlyA mutants against sheep erythrocytes and bovine and human lymphocyte cell lines (BL-3 and Raji cells, respectively) were analyzed . HlyAK563 and HlyAK689 substitutions displayed various degrees of loss of cytotoxicity that depended on the particular amino acid replacement . An HlyAK563C variant retained greater than 59 and 21% of its BL-3-lytic and erythrolytic activities, respectively, but was nearly inactive against Raji cells . An HlyA mutant with a K-to-E substitution at amino acid 689 (HlyAK689E) was essentially inactive against all three cell types, whereas an HlyAK689R substitution had a pattern of activity similar to that of the HlyAK563C mutant . Preceding the two in vitro acylated HlyA lysines are glycines that appear to be the only amino acids conserved in alignments of these regions among the RTX toxins . Remarkably, considering the retention of cytotoxic activity by some HlYAK689 mutants, each of three different substitutions at the HlyAG688 position was relatively inactive against all three cell types tested . This suggests that HlyAG688 plays a significant structural role in cytotoxic activity apart from its possible participation in an HlyC activation process which presumably requires recognition of pro-HlyA structures . The related RTX toxin, the Pasteurella haemolytica leukotoxin structural protein (LktA), can be activated in an E . coli recombinant background by HlyC . In amino acid sequence alignments, LktAK554 is equivalent to the HlyAK563 position but it has an asparagine (LktAN684) at the homologous HlyAK689 site . An LktAN684K substitution possesses wild-type leukotoxin activity against BL-3 cells and does not acquire hemolytic or Raji cell cytotoxic activity . Surprisingly, both LktAK554C and LktAK554T substitutions retain considerable BL-3 cytotoxicity (45 and 49%, respectively), indicating that there may be additional lysines within LktA that the HlyC activation mechanism is capable of acylating . Based on these results and a comparison of amino acid sequence alignments of 12 RTX toxins, a putative consensus structure of the RTX residues necessary for HlyC activation is hypothesized.

Biochemistry, 1996 Jul 30, 35(30), 9768 - 71
Enzymological characterization of the Pasteurella multocida hyaluronic acid synthase; DeAngelis PL; Hyaluronic acid (HA), a linear polysaccharide composed of alternating glucuronic acid and N-acetylglucosamine residues, is an essential molecule of higher vertebrates . The fowl cholera pathogen Pasteurella multocida Carter Type A also produces HA in the form of an extracellular capsule in order to evade host defenses . HA synthase activity could be obtained from cell-free membrane preparations of P . multocida . The enzyme utilized UDP-sugar precursors of HA in the presence of Mg2+ or Mn2+ at neutral pH . Mn2+ at 1 mM stimulated approximately 2-fold more incorporation than Mg2+ at 10 mM . On the other hand, the analogous enzyme from group A Streptococcus, HasA, is stimulated more by Mg2+ than Mn2+ . The apparent Michaelis constants, K(M), of the P . multocida HA synthase for UDP-N-acetylglucosamine and UDP-glucuronic acid were estimated to be approximately 75 and approximately 20 microM, respectively, in the presence of Mg2+, which suggests that the substrates are bound with 2-3-fold higher affinity than by the HasA enzyme . The rate enhancement observed with Mn2+ is apparently not due to better binding of the sugar nucleotide precursors complexed to Mn ion because the K(M) value, a measure of substrate affinity, increases by 25-50% in comparison to Mg2+ . In summary, the HA synthase from P . multocida, a Gram-negative bacterium, has kinetic optima distinct from those of HasA, the analog from the Gram-positive group A Streptococcus.

Ann N Y Acad Sci, 1996 Jul 23, 791, 359 - 68
Role of Pasteurella granulomatis and Dermatobia hominis in the etiology of lechiguana in cattle; Ladeira SL et al.; Attempts were made to reproduce bovine lechiguana, a disease associated with Dermatobia hominis and Pasteurella granulomatis infections . Suspensions of Pasteurella granulomatis were mixed with each of the following: saponin, oil adjuvant, ground Dermatobia hominis, or 5% mucin . Each preparation was inoculated into 6 cattle . Twelve more cattle, 6 of which received dexamethasone, were inoculated with bacterial suspension alone . Abscesses but no lechiguana was produced in all 36 cattle . After abscess regression, 12 cattle were reinoculated with a suspension of mouse-passed P . granulomatis . Only abscesses were produced . The intralymphatic inoculation of P . granulomatis in 6 cattle did not produce the disease . Eleven cattle infected naturally with D . hominis had lesions containing dead larvae . These lesions were inoculated with P . granulomatis . Nine cattle were experimentally infected with larvae of D . hominis that had been contaminated with the bacteria . No lechiguana lesions were produced in these 20 cattle . Six cattle with severe natural D . hominis infection were inoculated in the larval lesions with P . granulomatis . One developed lesions indistinguishable from those of natural lechiguana . The lesions regressed after treatment with chloramphenicol . D . hominis larvae and exudate from lesions caused by the fly were collected from 7 cattle on 3 farms and examined bacteriologically . P . granulomatis was isolated from the larvae and the exudate of a healthy calf from a farm where lechiguana had never been observed . These results suggest that P . granulomatis has a causal role in lechiguana, and that D . hominis may be a carrier of the bacterium . These observations suggest that lechiguana occurs when severe D . hominis lesions are infected with P . granulomatis . The apparent long incubation period, the negative results obtained in the other experiments, and also the infrequent occurrence of the natural disease suggest that lechiguana is a disease for which Koch's postulates are not easily fulfilled.

Dtsch Tierarztl Wochenschr, 1996 Jul, 103(7), 256 - 60
{Development of resistance in infectious agents of agricultural animals in Germany (1990-1994)--a review}; Trolldenier H; Antibiograms received from veterinary laboratories during the 1990-1994 period were recorded and evaluated with the aid of a computer program . Based on 70 tables giving information about th most important pathogens, the resistance behaviour of E . coli in cattle, swine, chicken, and turkey, that of Pasteurella haemolytica and P . multocida in cattle and swine and that of Staphylococcus aureus and Streptococcus agalactiae in cattle have been in synoptic form . Attention is drawn to the increase in resistance to enrofloxacin shown by E . coli, particularly in turkeys.

J Vet Diagn Invest, 1996 Jul, 8(3), 337 - 44
Minimum inhibitory concentration breakpoints and disk diffusion inhibitory zone interpretive criteria for tilmicosin susceptibility testing against Pasteurella spp . associated with bovine respiratory disease; Shryock TR et al.; Tilmicosin is a novel macrolide antibiotic developed for exclusive use in veterinary medicine . The first tilmicosin-containing product was approved to treat bovine respiratory disease associated with pasteurellae . The development of antimicrobial susceptibility testing guidelines for tilmicosin was predicated on the relationship of clinical efficacy studies that demonstrated a favorable therapeutic outcome, on pharmaco-kinetic data, and on in vitro test data, as recommended by the National Committee for Clinical Laboratory Standards (NCCLS) . The NCCLS-approved breakpoints for the MIC dilution testing are resistant > or = 32 micrograms/ml, intermediate 16 micrograms/ml, and susceptible < or = 8 micrograms/ml . The zone of inhibition interpretive criteria for disk diffusion testing with a 15-micrograms disk are resistant < or = 10 mm, intermediate 11-13 mm, and susceptible > or = 14 mm.

J Vet Diagn Invest, 1996 Jul, 8(3), 304 - 9
A specific and sensitive PCR assay suitable for large-scale detection of toxigenic Pasteurella multocida in nasal and tonsillar swabs specimens of pigs; Kamp EM et al.; A polymerase chain reaction (PCR) assay for the detection of toxigenic Pasteurella multocida in nasal and tonsillar swab specimens collected from pigs was developed . Target DNA was isolated with guanidine thiocyanate and diatomite, and 2 primer sets derived from sequences in the gene that encodes the dermonecrotic toxin of P . multocida were used simultaneously . The method was adapted to microtiter plate format allowing large-scale use of the PCR assay . To identify false-negative test results caused by failure of amplification, a positive control template was constructed that was spiked to each DNA sample . The PCR assay was evaluated with clinical samples and compared with 2 routinely used methods for detection of toxigenic P . multocida: isolation from a selective agar and direct detection of the toxin in extracts of primary cultures by an enzyme-linked immunosorbent assay (ELISA) . The sensitivity of the PCR assay was tested with 346 nasal and tonsillar swabs specimens collected from pigs of 9 herds known to be infected with toxigenic P . multocida . Toxigenic P . multocida was isolated from 22 specimens, only 28 specimens tested positive in ELISA, but 40 tested positive in the PCR assay; thus the PCR assay is the most sensitive of the 3 methods . The specificity of the PCR assay was tested with 372 swab specimens collected from pigs of 6 herds certificated to be free from toxigenic P . multocida . Toxigenic P . multocida was not isolated from any of these specimens, all tested negative in ELISA, and 370 tested negative in PCR . The 2 positive specimens came from 2 pigs of 1 litter and tested only weakly positive in the PCR assay . From these results, it was concluded that the PCR assay is not only highly sensitive but also highly specific.

J Vet Diagn Invest, 1996 Jul, 8(3), 296 - 303
Lesions in lambs experimentally infected with ovine adenovirus serotype 6 and Pasteurella haemolytica; Cutlip RC et al.; Twenty-five colostrum-deprived lambs reared in isolation were inoculated with a US variant of ovine adenovirus serotype 6 (OAV-6) strain RTS-151, Pasteurella haemolytica, or a combination of the 2 agents . Although severe pulmonary lesions were caused by each agent, the lesions were more severe and lasted longer with the combined infection . Lesions induced by OAV-6 alone developed 6-9 days after inoculation and lasted for 15 days, the length of the experiment . The lesions were characterized by suppurative inflammation at the junction of the terminal bronchioles and alveoli . Air spaces were filled with neutrophils and sloughed epithelial cells, which often contained large intranuclear inclusions . Lesions induced by P . haemolytica alone developed within 1 day and persisted for no more than 10 days and were characterized by severe pulmonary edema with variable amounts of fibrin . Lesions induced by the combined infection had aspects of each infection alone and resulted in severe disease in 4 of 8 lambs that were permitted to live more than 1 day after inoculation with bacteria . Early pulmonary lesions included edema, limited fibrin deposition, and slight purulent bronchiolitis and alveolitis . Later lesions included necrosis and more fibrin . For lambs inoculated with both pathogens, resolution was incomplete 15 days after inoculation of virus (10 days after inoculation of P . haemolytica) . The results presented here corroborate previous findings indicating that the RTS-151 variant of OAV-6 is common in lambs and acts in concert with P . haemolytica to cause severe and often fatal pneumonia.

Vet Microbiol, 1996 Jul, 51(1-2), 161 - 8
Derivation of Pasteurella multocida-free rabbit litters by enrofloxacin treatment; Suckow MA et al.; Pasteurella multocida is an important bacterial pathogen of rabbits that is easily transmitted from infected does to their kits prior to weaning . Enrofloxacin, a flouroquinolone antibiotic, is effective at limiting nasal carriage of P . multocida in rabbits . To determine if enrofloxacin treatment of pregnant does infected with P . multocida can be used to produce P . multocida-free litters, groups of 3 rabbits were inoculated intranasally on day 10 of gestation with 1.0 x 10(6) P . multocida CFUs . Beginning on day 14, one group received enrofloxacin IM (5 mg kg-1, BID), and a second group received enrofloxacin in the drinking water (200 mgl-1) . IM treatment continued until kindling, while PO treatment continued 1 week after kindling . A third group was infected but received only IM saline, and a fourth group was infected but not treated . In addition, a fifth group was neither infected nor treated . Culture of nasal lavage samples and tissues from does and kits showed that both routes of enrofloxacin treatment failed to completely eliminate P . multocida from does, but all kits from enrofloxacin-treated does were free from P . multocida . These results suggest that treatment does with enrofloxacin during the periparturient period may interrupt transmission of P . multocida from infected does to their kits and that this treatment may be useful for deriving Pasteurella-free rabbits from infected does.

Microb Pathog, 1996 Jul, 21(1), 59 - 64
Binding of host iron-binding proteins and expression of iron-regulated membrane proteins by different serotypes of Pasteurella multocida causing haemorrhagic septicaemia; Veken JW et al.; Pasteurella multocida strains of serotype B: 2,5, B: 3,4 and E: 2,5 are associated with haemorrhagic septicaemia in domestic and feral ruminants . These strains were investigated for their ability to bind transferrin, lactoferrin and haemoglobin and for their ability to use these host iron-binding proteins as a source of iron . All strains bound haemoglobin, none of the strains bound lactoferrin, whereas transferrin binding was restricted to serotype B: 2,5 strains . Growth experiments indicated that transferrin (serotype B: 2,5) and haemoglobin could restore bacterial growth under iron-depleted conditions . Two distinct serotype-independent profiles of iron-regulated membrane proteins were expressed in vitro as well as in vivo.

J Wildl Dis, 1996 Jul, 32(3), 521 - 6
Herpesvirus particles associated with oral and respiratory lesions in a California desert tortoise (Gopherus agassizii); Pettan-Brewer KC et al.; A 60-year-old captive California desert tortoise (Gopherus agassizii) which died in August 1990 at the University of California, Davis, California (USA), during treatment for colonic impaction had marked caseous necrosis of the oral cavity, choana, trachea, and lungs . Numerous intranuclear inclusion bodies and a large number of syncytial giant cells were seen in the oral cavity and respiratory tract along with bacterial granulomas . Pasteurella testudinis, Streptococcus veridans, and coagulase-negative Staphilococcus spp . were cultured from the lesions . Using electron microscopy, herpesvirus particles were observed in intranuclear inclusions and cytoplasm . Viral stomatitis, tracheitis, and bronchopneumonia complicated by bacterial infection were diagnosed . Although respiratory disease is common in desert tortoises, this is believed to be the first report of association with a viral infection.

Can J Vet Res, 1996 Jul, 60(3), 222 - 7
Serum haptoglobin concentration in growing swine after intranasal challenge with Bordetella bronchiseptica and toxigenic Pasteurella multocida type D; Francisco CJ et al.; The acute phase reaction, in association with progressive atrophic rhinitis (AR), was monitored for 3 wk using serum haptoglobin (HPT) quantification in thirty-six, 15 kg swine after intranasal challenge with varying doses of Pasteurella multocida type D (toxigenic strain) and Bordetella bronchiseptica . The challenge doses were administered alone or in combination with pigs divided into 9 isolated treatment groups . Increasing doses of B . bronchiseptica were associated with lower serum HPT (P < 0.05), whereas increasing doses of P . multocida tended to increase serum HPT (0.05 < P < 0.10) . Significant and positive correlation of mean HPT and AR score was found in these pigs; increased AR scores were associated with elevated mean HPT concentration (r = 0.41, P < 0.01) . A significant interaction between P . multocida and B . bronchiseptica dose indicated that increasing the dose of B . bronchiseptica, for a fixed P . multocida dose, was associated with less AR (P < 0.05) . The AR scores were greater in pigs given P . multocida, than B . bronchiseptica alone . These results indicate that a complex interaction between Pasteurella multocida and Bordetella bronchiseptica causes progressive atrophic rhinitis and alters serum HPT concentration in swine.

Am J Vet Res, 1996 Jul, 57(7), 1034 - 9
Effect of 5-hydroxytryptamine type-2 receptor blockade on pulmonary function in calves with experimentally induced Pasteurella haemolytica pneumonia; Hare JE et al.; OBJECTIVE: To evaluate a 5-hydroxytryptamine type-2 receptor antagonist, metrenperone (MET), in alleviating respiratory distress associated with experimentally induced Pasteurella haemolytica pneumonia in feedlot calves . DESIGN: Double-blind controlled clinical trial . ANIMALS: 30 healthy 6- to 8-month-old Hereford-type calves (250 to 450 kg) . PROCEDURE: Initial measurements were made of rectal temperature (RT), arterial blood gas (ABG) tensions, and pulmonary mechanics . Calves were then infected with P haemolytica in logarithmic phase of growth by intratracheal inoculation . 18 hours later, determination of RT and ABG tensions, and pulmonary function testing were repeated and calves were selected for inclusion in the study on the basis of having 2 of the following: respiratory rate > 50 breaths/min, RT > 40 C, or PaO2 > 20 mm of Hg below the baseline value . MET (0.1 mg/kg of body weight, IM) or an equivalent vehicle dose was then administered . RT, ABG, and pulmonary mechanics measurements were repeated at 0.5, 1, 2, 3, 4, 6, 12, and 24 hours after treatment . Calves were then euthanatized, and gross necropsy scoring and histologic examination were performed on the lungs . RESULTS: Infection with P haemolytica caused significant increases in RT and respiratory rate, and reduction in PaO2, PaCO2, and tidal volume 18 hours after inoculation . MET-treated calves and significantly reduced rectal temperature between 1 and 12 hours, compared with vehicle-treated calves . In addition, MET-treated calves had reduced respiratory rate with concomitantly increased tidal volume between 0.5 and 2 hours after treatment, compared with vehicle-treated calves . Necropsy revealed acute lobar bronchopneumonia in all 30 calves, but there was no difference in necropsy score between treatment groups . CONCLUSIONS AND CLINICAL RELEVANCE: MET may have an antipyretic effect on calves with pneumonia caused by P haemolytica . Its influence on pulmonary mechanics was minimal however, and it did not induce lung lesions in the short term.

Br Vet J, 1996 Jul, 152(4), 453 - 8
The goat as a model for studies of pneumonic pasteurellosis caused by Pasteurella multocida; Zamri-Saad M et al.; A model of pneumonic pasteurellosis has been established in goats using Pasteurella multocida harvested from pneumonic lungs of goats (types A and D), rabbits (type A) and sheep (type D) . The resultant infections were acute, subacute or chronic . The gross and histological lesions of the subacute and chronic infections were typical of pneumonic pasteurellosis . P . multocida type D produced significantly (P < 0.01) more severe lesions when compared with other isolates . There were strong correlations between the clinical signs and the severity of lesions.

Int J Syst Bacteriol, 1996 Jul, 46(3), 736 - 44
Phylogenetic relationships and diversity within the Pasteurella haemolytica complex based on 16S rRNA sequence comparison and outer membrane protein and lipopolysaccharide analysis; Davies RL et al.; The outer membrane protein (OMP) and lipopolysaccharide (LPS) profiles of 30 untypeable isolates of Pasteurella haemolytica were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and compared with the profiles of typeable isolates . The phylogenetic relationships of 28 isolates representing each of the serotypes of P . haemolytica and Pasteurella trehalosi, as well as untypeable isolates of P . haemolytica, were determined by comparing 16S rRNA sequences . The analysis of the OMP and LPS profiles of the untypeable isolates revealed five groups, which were designated untypeable groups 1 (UG1) through UG5 . The UG1 and UG2 isolates had OMP and LPS profiles identical to the profiles of certain serotype A1 and A2 isolates, respectively . Furthermore, UG1 isolates originating from cattle and sheep could be clearly differentiated on the basis of their OMP profiles . The OMP and LPS profiles of UG3 isolates were similar appearance to the profiles of serotype A11 isolates, suggesting that these two groups are closely related . The OMP profiles of UG4 and UG5 isolates were unique and different from the OMP profiles of the UG1 through UG3 isolates . A comparison of 16S rRNA sequences revealed that typeable isolates of P . haemolytica could be divided into the following three groups: (i) serotype A1, A5 through A9, A12 through A14, and A16 isolates, (ii) serotype A2 isolates, and (iii) serotype A11 isolates . the isolates belonging to the first group all had identical sequences, whereas the sequences of isolates belonging to the second and third groups differed from the sequences of the isolates belonging to the first group at two and four base positions, respectively . The sequence data for the untypeable isolates confirmed the conclusions derived from the OMP and LPS analysis . Isolates belonging to UG1 and UG2 were identical to serotype A1 and A2 isolates, respectively; isolates belonging to UG3 were related to serotype A11 isolates, although there was some sequence heterogeneity within this group; and isolates belonging to UG4 and UG5 were more distantly related to P . haemolytica than were isolates belonging to UG1 through UG3 and were clearly members of two different species . As expected, isolates of P . trehalosi were event more distantly related to P . haemolytica than were the untypeable isolates, but there was significantly more sequence variation among the four serotypes of this species than there was among the serotypes of P . haemolytica . The correlation of the OMP and LPS data with the 16S rRNA sequence data suggested that OMP and LPS analyses might be useful for preliminary screening and comparing large numbers of isolates in taxonomic and epidemiological studies of the Pasteurellaceae.

Int J Syst Bacteriol, 1996 Jul, 46(3), 648 - 52
Actinobacillus delphinicola sp . nov., a new member of the family Pasteurellaceae Pohl (1979) 1981 isolated from sea mammals; Foster G et al.; We performed phenotypic and phylogenetic studies of a gram-negative, rod-shaped bacterium isolated from cetaceans . The results of a 16S rRNA gene sequence analysis demonstrated that this bacterium represents a previously unknown line of descent in the family Pasteurellaceae . On the basis of the results of our phylogenetic analysis and phenotypic criteria, we propose that this organism should be classified as a new species, Actinobacillus delphinicola sp . nov . The type strain of A . delphinicola sp . nov . is strain NCTC 12870.

Zentralbl Veterinarmed B, 1996 Jul, 43(5), 293 - 304
Observations on haemorrhagic septicaemia in Pakistan livestock; Sheikh MA et al.; Information based on field observations of Veterinary Officers in nine districts of Punjab, Pakistan showed 11% incidence, 9% mortality and 78% case fatality rates of haemorrhagic septicaemia in buffalo, whereas these values were 4%, 2.5% and 62% in cattle . Disease incidence was higher in 0-24-month-old animals and groups of less than 10 animals . The disease was seasonal, occurring only in rainy seasons of the year, and victims were only cattle and buffalo . The clinical course of the disease was generally 1-2 days . symptoms included high temperature, salivation, swelling of the throat and difficulty in breathing and could result in death . Successful treatment was reported if antibiotics were given at the initial stages of the disease . Various combinations of sulphur drugs and antibiotics were considered more effective . The results of the questionnaire survey suggest that a favourable response was obtained using clamoxyl LA, farmox 15%, vesulong, gentakel and chloramphenicol . Previous vaccination of livestock with the alum-precipitated formalinized broth culture of Pasteurella multocida vaccine (bacterin) was not considered to protect against field outbreaks.

J Dermatol, 1996 Jul, 23(7), 502 - 4
Three cases of Pasteurella multocida skin infection from pet cats; Matsui T et al.; We encountered three cases of Pasteurella multocida skin infection from pet cats . P . multocida wound infections are characterized by acute onset of erythema, pain, and swelling . This infection has rarely been reported in dermatology journals from Japan.

FEMS Microbiol Lett, 1996 Jul 1, 140(2-3), 165 - 9
A minimal medium for growth of Pasteurella multocida; Jablonski PE et al.; We developed a minimal medium supporting the growth of both toxigenic and nontoxigenic strains of Pasteurella multocida to optical densities of > 0.5 (600 nm) . P . multocida P1059 (ATCC 15742), one of a number of strains which can cause fowl cholera, was used as the model strain in this study . The medium was composed of 17 ingredients including cysteine, glutamic acid, leucine, methionine, inorganic salts, nicotinamide, pantothenate, thiamine, and an energy source . Leucine was not required for growth but was stimulatory, and thiamine could be replaced by adenine . An additional 46 strains of P . multocida were tested, and 40 out of 46 (87%) strains grew as well as strain P1059 through a minimum of 10 serial transfers . P . multocida toxin (PMT) was produced when cells of a known toxigenic strain (P4261) were cultivated in the minimal medium . No growth of Pasteurella Haemolytica or Pasteurella trehalosi strains was observed in this minimal medium.

Microbiology, 1996 Jul, 142 ( Pt 7), 1895 - 907
Intra-specific diversity and host specificity within Pasteurella haemolytica based on variation of capsular polysaccharide, lipopolysaccharide and outer-membrane proteins; Davies RL et al.; Intra-specific diversity within Pasteurella haemolytica was assessed by analysing variation in the capsular polysaccharide (serotypes), lipopolysaccharide (LPS) and outer-membrane proteins (OMPs) of 184 isolates recovered from cattle and sheep . Four 12 serotypes comprised 83% of the total number of isolates, including A1 and A2 as the most frequently recovered serotypes from cattle and sheep, respectively . Nine distinct LPS profiles were identified . Four different core-oligosaccharide patterns were present, each of which occurred alone as rough LPS and also in association with single O-antigen profile as smooth LPS; the ninth LPS type was also smooth but had a different O-antigen profile . The capsular serotypes could be divided into four groups based on the dominant LPS profile within each serotype: (1) A1, A6, A9, A12 and A5; (2) A2, A8, A14 and A16; (3) A7 and A13; and (4) A11 . Smooth LPS of type 1A, which was found only in the first group, was associated primarily with bovine disease isolates, whereas rough LPS of types 1B and 3B were associated primarily with group 2 serotypes and ovine disease isolates . Similarly, the variation of OMP profiles generated three groups: (1) A1, A6 A9, A12, A5 and A8; (2) A2, A14 and A16; and (3) A7, A11 and A13 . Isolates belonging to groups 2 and 3 exhibited greater diversity in their OMP profiles than those belonging to group 1 . Although the majority of group 3 isolates possessed profiles unique to that group, a smaller number of A7 isolates possessed profiles with similarities to those of serotypes A1 or A2 . OMP profiles clearly differentiated bovine from ovine isolates of the same serotypes . The association both of specific LPS and OMP profiles with bovine or ovine disease isolates suggested a correlation between specific cell-surface structures and host specificity . The combined analysis of capsular serotypes, LPS types and OMP profiles identified seven major groups within P . haemolytica which were responsible for 59% of the disease cases, suggesting a clonal structure for this species . Overall, comparison of the capsular serotypes, LPS types and OMP profiles proved extremely useful for assessing diversity within P . haemolytica.

Microbiology, 1996 Jul, 142 ( Pt 7), 1739 - 47
Binding-protein-dependent arginine transport in Pasteurella haemolytica; Caskey LS et al.; A periplasmic arginine transport system that is a member of the ATP -dependent transport superfamily was identified in Pasteurella haemolytica . The gene encoding the periplasmic binding protein (lapT) was cloned and the protein overexpressed in Escherichia coli . LapT was purified to homogeneity using a modified osmotic shock procedure and anion-exchange column chromatography . Filter-binding assays established that LapT is an L-arginine-binding protein . Various amino acids were tested for their ability to inhibit L-arginine binding to LapT . When present in 100-fold excess, only L-arginine, D-arginine and citrulline competed with L-arginine for binding . Arginine transport in P . haemolytica whole cells was competitively inhibited by the same amino acids, suggesting that the LapT permease specifically transports L-arginine . The dissociation constant for the L-arginine-LapT complex was 170 nM and the stoichiometry of binding was approximately 0.8 mol L-arginine (mol LapT)-1 . A polyclonal antibody raised against the purified protein permitted detection of LapT in P . haemolytica periplasmic fractions.

Infect Immun, 1996 Jul, 64(7), 2687 - 94
Pasteurella haemolytica leukotoxin induces bovine leukocytes to undergo morphologic changes consistent with apoptosis in vitro; Stevens PK et al.; Infection of the bovine lung with Pasteurella haemolytica results in an acute respiratory disorder known as pneumonic pasteurellosis . One of the key virulence determinants used by this bacterium is secretion of an exotoxin that is specific for ruminant leukocytes (leukotoxin) . At low concentrations, the leukotoxin can activate ruminant leukocytes, whereas at higher concentrations, it inhibits leukocyte functions and is cytolytic, presumably as a result of pore formation and subsequent membrane permeabilization . We have investigated the possibility that the activation-inhibition paradox is explained in part by leukotoxin-mediated apoptosis (i.e., activation-induced cell death) of bovine leukocytes . Incubation of bovine leukocytes with P . haemolytica leukotoxin caused marked cytoplasmic membrane blebbing (zeiosis) and chromatin condensation and margination, both of which are hallmarks of apoptosis . The observed morphologic changes in bovine leukocytes were leukotoxin dependent, because they were significantly diminished in the presence of an anti-leukotoxin monoclonal antibody . In addition, bovine leukocytes incubated with culture supernatant from a mutant strain of P . haemolytica that does not produce any detectable leukotoxin failed to exhibit the morphologic changes characteristic of cells undergoing apoptosis . These observations may represent an important mechanism by which P . haemolytica overwhelms host defenses, contributing to the fibrinous pleuropneumonia characteristic of bovine pasteurellosis.

Am J Gastroenterol, 1996 Jul, 91(7), 1447 - 9
Exposure to domestic cats: risk factor for Pasteurella multocida peritonitis in liver cirrhosis?
Koch CA, Mabee CL, Robyn JA, Koletar SL, Metz EN.
Pasteurella multocida is most commonly associated with acute skin and soft tissue infections following an animal bite or scratch . Peritonitis caused by P . multocida in patients with cirrhosis is rarely reported . We present a case of spontaneous bacterial peritonitis with P . multocida in a patient with cirrhosis, squamous cell cancer of the head and neck, and nontraumatic domestic cat exposure . Nasopharyngeal colonization with P . multocida, with subsequent transient bacteremia and seeding of the peritoneum in immunocompromised (particularly cirrhotic) cat-owners, could play an important pathogenetic role in the development of spontaneous bacterial peritonitis . A review of the literature showed that in nine of 13 patients with cirrhosis and P . multocida peritonitis, exposure to domestic animals was reported . The mortality rate is high in this setting, even with prompt antibiotic treatment . Preventive strategies for immuno-compromised patients should include minimization of animal contact, especially cats, which have a high carriage rate (70-90%) of P . multocida.

J Cell Physiol, 1996 Jul, 168(1), 173 - 82
Pasteurella multocida toxin stimulates mitogenesis and cytoskeleton reorganization in Swiss 3T3 fibroblasts; Dudet LI et al.; Pasteurella multocida toxin (PMT) causes cytoplasmic retraction in epithelial cells, activates osteoclast neoformation, and is a potent mitogen for Swiss 3T3 fibroblasts . In the present study designed to further investigate the effects of PMT on cell shape and proliferation, we report that the mitogenic effect of affinitypurified PMT on quiescent 3T3 cells was even superior at 5 ng/ml to that of fetal bovine serum or bombesin . This positive effect was inhibited by heat denaturation and methylamine treatment (this agent blocks internalization) . Preincubation of PMT with gangliosides GM1, GM2, or GM3 counteracted its effect on DNA synthesis, suggesting that the toxin binds to GM-type ceramides on target cells . The distribution of F-actin was analyzed in control/treated cells using FITC-conjugated phalloidin . In comparison with FBS and bombesin, PMT triggered a more rapid and profound reorganization of cortical actin into prominent stress fibers after only 5-10 min . This event lead to the retraction of cells after only 30 min and ultimately to the induction of mitotic figures . Interestingly, methylamine blocked the effects of PMT on stress fiber formation and cell retraction but not the ruffling response, suggesting that some early events may not require toxin internalization . In summary, these findings indicate that PMT concomitantly exerts a strong mitogenic activity and a rapid stimulation of cytoskeletal rearrangements, possibly after binding to membrane gangliosides and subsequent internalization . We propose that this toxin could be used in the future as a defined inducer of transduction signals involved in cellular proliferation and control of cell shape.

J Am Vet Med Assoc, 1996 Jun 15, 208(12), 2035 - 42
Epidemiologic and pathologic characteristics of respiratory tract disease in dairy heifers during the first three months of life; Virtala AM et al.; OBJECTIVE--To describe the incidence of respiratory tract disease in dairy calves and to compare antibody titers and microbial isolates from transtracheal wash samples between calves with and without respiratory tract disease (cases and controls, respectively) . DESIGN--Prospective observational cohort study, with matched case-control substudy . ANIMALS--410 dairy heifers; in substudy, 105 cases and 59 controls from the same population . PROCEDURE--Calves were examined weekly by a veterinarian during the first 3 months of life . Blood samples were collected for serologic testing at the first visit for each calf and during acute and convalescent periods for cases . Transtracheal wash samples also were obtained during the acute period from cases and controls . RESULTS--Incidence and case-fatality risk for clinician-diagnosed pneumonia were 25.6 and 2.2%, respectively . Mycoplasma sp and Pasteurella multocida together were isolated from 29% of cases and 11% of controls, and Mycoplasma sp alone from 7% of cases and 30% of controls (both P < or = 0.05) . From postcolostral to acute-phase serum samples . Mycoplasma dispar titers increased 1.3-fold among cases, compared with 0.7-fold among controls; from acute- to convalescent-phase samples, M dispar titers increased 2.4-fold among cases, compared with 5.6-fold among controls (both P < or = 0.005) . CLINICAL IMPLICATIONS--Results of this study suggested a synergistic effect between Mycoplasma sp and P multocida and a possible initiative role of M dispar in the development of respiratory tract disease . Postcolostral total IgG values and antibody titers were not significantly different between cases and controls, implying that other factors have an important role in the development of respiratory tract disease.

Microb Pathog, 1996 Jun, 20(6), 361 - 75
Induction of nitric oxide production by bovine alveolar macrophages in response to Pasteurella haemolytica A1; Yoo HS et al.; We assessed the kinetics of inducible nitric oxide synthase (iNOS) mRNA expression and production of nitric oxide (NO) in bovine alveolar macrophages (AMs) stimulated with purified lipopolysaccharide (LPS) from Pasteurella haemolytica strain 12296 . The effect of LPS on iNOS gene expression was dose-dependent and was expressed maximally at 24 h after stimulation with 10 micrograms/ml of LPS . Production of NO measured as secreted nitrite in supernatants took place in a time and dose-dependent manner with peak production at 24 h after LPS stimulation . Recombinant bovine gamma interferon (rb gamma IFN) augmented the LPS-induced iNOS gene expression and production of NO . The ability of LPS to induce iNOS gene expression and NO production either alone or in combination with rb gamma IFN was significantly abrogated by polymyxin B . In addition, the iNOS inhibitor NG-monomethyl-Larginine (L-NMMA) significantly inhibited LPS and rb gamma IFN + LPS induced NO production . Our results also demonstrated that NO produced from an exogenous NO donor sodium nitroprusside (SNP), and NO generated from LPS-stimulated AMs (endogenous) caused cytotoxic injury to bovine pulmonary artery endothelial cells in a dose-dependent manner . The cytotoxic injury caused by NO generated from LPS stimulated AMs was inhibited by polymyxin B or L-NMMA . There was a markedly increased concentration of nitrite in the lung lavage fluids of calves following P . haemolytica infection . These findings support a role for NO in the pathogenesis of lung injury in bovine pneumonic pasteurellosis.

Comp Immunol Microbiol Infect Dis, 1996 Jun, 19(3), 171 - 9
Respiratory infections of sheep; Martin WB; Sheep respiratory infections appear as differing clinical syndromes . Mild, acute infections are usually due to parainfluenza 3 (PI3) virus . A mild but chronic respiratory problem in lambs under 1 year old is thought to be caused by Mycoplasma ovipneumoniae probably in association with Pasteurella and PI3 . Acute bacterial pneumonia usually results from infection with Pasteurella of biotype A . Infection with PI3 can initiate invasion by Pasteurella . Bordetella parapertussis infection has also been implicated . Serotypes of biotype T P . haemolytica cause an acute septicaemia . Stressful management practices may be a predisposing factor . Chronic proliferative pneumonia results from infection by retroviruses of pulmonary adenomatosis or maedi-visna . Both infections have incubation periods extending into years . The former produces fatal tumorous masses in the lungs . Diagnostic tests are being actively sought . Maedi-visna can present as several clinical problems, frequently as an insidious but fatal proliferative pneumonia.

Vet Immunol Immunopathol, 1996 Jun 1, 51(3-4), 277 - 92
Serum haptoglobin as an indicator of the acute phase response in bovine respiratory disease; Godson DL et al.; The early stages of the host response to infectious agents include a number of physiologic changes, collectively known as the acute phase response . The acute phase response is comprised of reactions localized at the site of infection, as well as the initiation of systemic responses, which include a rapid increase in the serum concentration of some proteins, known as acute phase proteins (APP) . Using polyacrylamide gel electrophoresis, we detected two APP of approximately 22 and 37 kDa molecular weight in sera obtained from cattle with bovine respiratory disease (BRD) . Based on their presence in the sera of sick, but not normal animals, the molecular weights, N-terminal amino acid sequence analysis, and the ability to bind hemoglobin, we identified these proteins as the alpha and beta subunits of haptoglobin . The haptoglobin molecule and the alpha subunit were isolated from serum, purified, and used to produce monoclonal and polyclonal antibodies . With these reagents, an enzyme linked immunosorbent assay was developed to measure the concentration of haptoglobin in bovine serum . Using an experimental model of BRD induced by a sequential challenge of calves with bovine herpesvirus type-1 and Pasteurella haemolytica, we observed a temporal relationship between the increase in haptoglobin concentration in serum and the onset of bacterial infection . The haptoglobin concentration ranged from undetectable in the serum of most calves prior to challenge, to greater than 1 mg ml(-1) in over one-third of the calves at the height of disease . Furthermore, the concentration of haptoglobin was associated significantly with other measures of the severity of disease . Together, these results indicate that quantification of acute phase proteins in animals with BRD could be a valuable diagnostic and prognostic aid.

Antimicrob Agents Chemother, 1996 Jun, 40(6), 1561 - 3
Sensitization of bacteria to danofloxacin by temperate prophages; Froshauer S et al.; Danofloxacin (CP-76,136) is in a class of agents that inhibit DNA gyrase and trigger induction of the SOS response and temperate bacteriophages . Killing studies against the bovine pathogen Pasteurella haemolytica demonstrated that danofloxacin exhibits particularly rapid killing kinetics . Here, lysogenic Escherichia coli bearing lambda is found to be more sensitive to danofloxacin than nonlysogenic E . coli . Danofloxacin exposure also induced a prophage in P . haemolytica . The potency of danofloxacin against lysogens in likely enhanced by this prophage induction.

Antimicrob Agents Chemother, 1996 Jun, 40(6), 1558 - 60
Distribution of tet(H) among Pasteurella isolates from the United States and Canada; Hansen LM et al.; Tetracycline-resistant isolates of Pasteurella multocida and Pasteurella haemolytica obtained from various locations in the United States and Canada were studied to determine the distribution of the tet(H) gene . Of the 31 isolates examined, 25 were found to contain the tet(H) gene . Chromosomal or plasmid DNA obtained from those that did not contain the tet(H) gene did not hybridize with probes specific for classes A through G, though chromosomal DNA from one isolate lacking tet(H) hybridized with a probe specific for class M . The tet(H) gene was found on plasmid as well as on chromosomal DNA, suggesting that it is carried on a transposable element.

Am J Vet Res, 1996 Jun, 57(6), 848 - 52
Effect of Pasteurella multocida toxin on physeal growth in young pigs; Ackermann MR et al.; OBJECTIVE: To determine whether Pasteurella multocida toxin (PMT) affects growth of the proximal portion of the humerus of young pigs . ANIMALS: 20 colostrum-deprived, cesarean-derived pigs . DESIGN AND PROCEDURE: 5 groups (n = 4/group) of pigs were formed . Group-1 pigs received 0.1 ml of phosphate-buffered saline solution for 4 weeks; group-2 pigs received 0.05 microgram of PMT/kg of body weight at 14 and 21 days; group-3 pigs received 0.05 microgram of PMT/kg at 28 and 35 days; group-4 pigs received 0.1 microgram of PMT/kg at 14 and 21 days; and group-5 pigs received hyperimmune serum (from a sow given purified toxin) on days 13, 20, 27, and 34, and 0.1 microgram of PMT/kg on days 14, 21, 28, and 35 . RESULTS: All pigs given 0.1 microgram of PMT/kg without serum died or were euthanatized, as were 4 pigs given 0.05 microgram of PMT/kg . These pigs had increased serum interleukin 1 and 6 bioactivities . Pigs surviving 0.05 microgram of PMT had decreased weight gain, rough coat, marked atrophy of the ventral concha (as determined by turbinate perimeter ratios), and small stature . The surviving pigs also had reduced area and decreased proliferation indices in physeal chondrocytes on the basis of bromodeoxyuridine immunoreactivity . Control and serum-treated pigs gained weight, had no clinical effects, had similar physeal areas, and had higher cell proliferation indices . CONCLUSIONS: PMT inhibits endochondral bone formation by reducing physeal area and chondrocyte proliferation in vivo . Hyperimmune serum neutralizes the effects of toxin on weight gain, clinical appearance, physeal area, and chondrocyte proliferation . CLINICAL RELEVANCE: PMT may affect growth of the skeletal system . Antiserum to PMT is protective.

Exp Hematol, 1996 Jun, 24(7), 795 - 806
Identification of CD34+ subsets after glycoprotease selection: engraftment of CD34+Thy-1+Lin- stem cells in fetal sheep; Sutherland DR et al.; Epitopes on the CD34 molecule detected by some CD34 antibodies can be cleaved by a unique glycoprotease from Pasteurella haemolytica, which cleaves only glycoproteins rich in O-linked glycans . A method to isolate CD34+ cells from adult bone marrow was developed subsequently, in which CD34+ cells were isolated in high purity and yield following immunomagnetic bead selection and detachment with the glycoprotease . Using a variety of other cell-surface markers shown here to be insensitive to glycoprotease, committed progenitors of T lymphoid, B lymphoid, monomyeloid, megakaryoblastic, or erythroid lineages could be identified . Significantly, candidate hematopoietic stem cells (HSC) that are contained within a CD34+Lin- (CD2-, CD14-, CD15-, CD16-, CD19-) (or CD34+CD38-) subset expressing the Thy-1 antigen (CDw90), c-kit receptor (CD117), and CDw109 but lacking expression of CD71 and HLA-DR antigens also were detected . Functionally distinct subsets of glycoprotease-selected CD34+ cells were identified and subfractionated using flow cytometry and fluorescence-activated cell sorting (FACS) . These subsets included candidate HSCs expressing the CD34+Thy-1+Lin- phenotype, which were sorted from a CD34+ fraction of a mobilized peripheral blood (MPB) sample . In a fetal sheep model, when CD34+Thy-1+Lin- cells were injected intraperitoneally, they were capable of homing to the marrow, where they generated long-term multilineage hematopoiesis and maintained human CD34+ cells, indicating that candidate HSC subsets of CD34+ cells selected with this highly specific enzyme were capable of engraftment in vivo . The ability to identify and purify virtually any phenotypically defined subset of glycoprotease-selected CD34+ stem/progenitor cells should facilitate the study of hematopoiesis in vitro and in animal models in vivo as well as the development of novel genetic techniques for the correction of specific blood cell disorders in humans.

Can J Physiol Pharmacol, 1996 May, 74(5), 572 - 9
Hemodynamic responses to Pasteurella haemolytica inoculation in calves given type 2 serotonergic antagonist; Desmecht D et al.; The effects of saline (control, group C) and metrenperone (treated, group M) on systemic and pulmonary hemodynamics were determined in conscious 7- to 15-day-old calves after they were intratracheally inoculated with Pasteurella haemolytica . Metrenperone, a specific serotonin (5-hydroxytryptamine) receptor antagonist, was injected intramuscularly (100 micrograms.kg-1) 2 h after the calves were inoculated . Central venous, pulmonary arterial and capillary wedge, and systemic arterial pressures were measured, using fluid-filled catheters . Cardiac output was measured by the thermodilution technique . Heart rate, stroke volume, and pulmonary and systemic vascular resistances were calculated . The parameters were measured hourly from the 1st to the 10th h after inoculation . In group C, cardiovascular response to P . haemolytica inoculation was marked and typically consisted of two systemic hypotensive phases and two pulmonary hypertensive phases . The first phase occurred by the 2nd h post inoculation and was induced by a transient bradycardia and a systemic vasodilation, leading to profound hypotension and reduced venous return . Cardiac performance then transiently recovered, but systemic hypotension persisted . The second hypotensive hypodynamic phase occurred by the 7th h after inoculation, and was associated with a decline in stroke volume, an increase in heart rate, and pulmonary hypertension and vasoconstriction . In group M, the early response to P . haemolytica exposure was similar to that in controls, indicating that, as in sheep, 5-hydroxytryptamine does not contribute to the early hypodynamic response to endotoxemia . In contrast, metrenperone completely abolished late increases in pulmonary arterial pressure and pulmonary vascular resistance, suggesting that 5-hydroxytryptamine contributes to the late pulmonary vasoconstriction . Metrenperone treatment also allowed better restoration of heart rate, and hence, cardiac output was maintained . In conclusion, 5-hydroxytryptamine might have a role in mediating pasteurellic endotoxin induced changes in pulmonary hemodynamics through its type-2 receptors.

J Comp Pathol, 1996 May, 114(4), 373 - 84
A pathological and immunohistochemical study of caprine pleuropneumonia induced by subspecies of Mycoplasma mycoides; Rodriguez JL et al.; In a population of 700 goats, 150 died; of these, 29 were necropsied . Ten of the 29 goats had pleuropneumonia . Mycoplasma mycoides subsp . mycoides (Large Colony) (MmmLC), Mycoplasma mycoides subsp . capri (Mmc), and Pasteurella multocida were isolated from five of the pleuropneumonic goats . Gross and microscopical lesions were typical of caprine pleuropneumonia (CPP), with bronchopneumonia, fibrinopurulent or fibrinonecrotic pleuropneumonia and dilatation of the interlobular septa and pleura . Immunohistochemical examination with antisera against MmmLC and Mmc showed mycoplasma antigens in all 10 goats with CPP . In all cases, both MmmLC and Mmc antigens were detected together . Mycoplasma antigens were present in the lumina of the airways and alveoli, mainly inside the cytoplasm of neutrophils and macrophages, but extracellular antigen was demonstrated in areas of necrosis . Pasteurella antigens were detected in four of the 10 animals with CPP . From the histological, immunohistochemical and microbiological results it was concluded that the two mycoplasmas, acting together, caused the pleuropneumonia, with P . multocida playing a subsidiary synergistic role.

J Comp Pathol, 1996 May, 114(4), 347 - 60
Passive immune cross-protection in mice produced by rabbit antisera against different serotypes of Pasteurella multocida; Rimler RB; Haemorrhagic septicaemia (HS) and fowl cholera (FC) are specific diseases caused by certain serotypes of Pasteurella multocida . Strains that usually cause HS in cattle and water buffalo do not produce FC in avian species, and strains that cause FC do not produce HS in cattle and water buffalo . A variety of P . multocida serotypes, including unusual strains which can cause HS in wild ruminants, were evaluated in passive immune protection studies to determine the immunological relationship between strains associated with HS and FC . Various degrees of cross-protection were seen among the strains . Antiserum against a serotype B:3,4 strain protected against strains capable of causing HS (serotypes B:1, B:2, B:3,4, B:4 and E:2) and FC (serotypes A:1, A:3 and A:5) . Antiserum against an FC strain (serotype A:5) similarly protected against strains capable of causing HS and FC . Antigenic analyses indicated that cross-protection was not necessarily induced by serotype-specific capsular (beta) or somatic (gamma) antigens or major porin protein . SDS-PAGE and immunoblots of whole cell lysates of the different HS and FC strains showed many protein-staining bands with similar mobilities and antigenic activity . These cross-reactive antigenic bands occurred in the 20- to 120-kDa range . Adsorption of antiserum with a heterologous serotype removed its reactivity with most of these bands, as well as its ability to cross-protect.

Vet Microbiol, 1996 May, 50(1-2), 143 - 8
Tn10 insertional mutagenesis in Pasteurella multocida; Lee MD et al.; The objective of this study was to identify a transposon that will randomly and stably integrate in the genome of Pasteurella multocida . Using the suicide conjugative delivery system, pLOF, containing a kanamycin resistance marked Tn10 insertion element, we determined that Tn10 is effective in producing insertional mutations in this species . Combined conjugation/transposition events occurred once per 10,000 donor cells . Only 1.4% of the isolates resulted from vector integration and the genomic insertions were random and stable as determined by DNA/DNA hybridization after 10 serial subcultures lacking antibiotic selection . Twenty-two percent of the isolates were auxotrophic, 4% were tryptophan auxotrophs . Mutants derived by this method will be useful for studying putative virulence determinants of Pasteurella.

Vet Immunol Immunopathol, 1996 May, 51(1-2), 173 - 8
Effect of Pasteurella multocida vaccination on buffalo polymorphonuclear hydrogen peroxide and nitric oxide production; Roy SC et al.; An attempt was made to investigate the effect of Pasteurella multocida on certain microbicidal reactive oxygen and nitrogen intermediates released by the polymorphonuclear cells (PMNs) from the vaccinated animals . The PMNs from the peripheral blood of both control and experimental buffaloes vaccinated against haemorrhagic septicaemia were isolated . PMNs from control animals upon activation with P . multocida lipopolysaccharide (LPS) and live P . multocida cells generated higher levels of hydrogen peroxide (H2O2) and nitric oxide (NO-) than the non-activated cells (P < 0.01) . In the presence of P . multocida LPS, PMNs from animals vaccinated against haemorrhagic septicaemia generated significantly higher H2O2 (P < 0.05) and NO- (P < 0.01) than the PMNs from control animals . L-Arginine when added to the activation medium enhanced the production of NO- in a dose-dependent manner . This indicated the role of arginine in NO- production . The study suggested that buffalo PMNs possessed a potent oxidant defence system even in the presence of P . multocida, an antiphagocytic bacterium.

Vet Immunol Immunopathol, 1996 May, 51(1-2), 113 - 26
The phenotype and phagocytic activity of macrophages during maedi-visna virus infection; Lee WC et al.; Macrophages from maedi-visna virus (MVV) infected sheep have been shown to have an activated phenotype from sites of lesions in vivo . Here we have looked at the direct effect of virus infection on macrophage phenotype and activity in vitro by flow cytometry . There was no significant difference in the expression of several surface markers (CD4, CD8, MHC Class I, MHC Class II, lymphocyte function associated antigen(LFA)-1 and LFA-3) on monocyte-derived macrophages (MDM) by 5 days post MVV infection . In contrast the phagocytic activity of MVV-infected MDM for the yeast Candida utilis and erythrocytes was decreased by 5 days p.i . although the surface binding of erythrocytes was not affected . Interestingly, an activated phenotype was seen on alveolar macrophages (AM) from sheep with maedi (surface expression of MHC Class I, Class II and LFA-1 was increased), but there was no difference in the binding and phagocytosis of erythrocytes by these cells . However the binding and phagocytosis of the bacterium, Pasteurella hemolytica was increased with AM from MVV-infected sheep without lesions . Similarly there was no significant difference in the phagocytic and erythrocyte rosetting activity between fresh monocytes from MVV-infected and uninfected control sheep . Therefore the phenotype of macrophages taken from sites of lesions caused by MVV does not correspond to a direct effect by the virus on these cells or to particular activities of the macrophages.

Berl Munch Tierarztl Wochenschr, 1996 May, 109(5), 168 - 71
{Resistance pattern of bovine Pasteurella}; Hormansdorfer S et al.; The sensibility of 375 pasteurellae of bovine origin (215 pasteurella multocida--and 160 pasteurella haemolytica--strains) was examined against 16 antibiotics or chemotherapeutics by agar diffusion technique . A great part of the strains was resistant to oxacillin (41,18%), tylosin (79,14%), streptomycin (53,21%), sulfonamides (57,33%) and tetracycline (47,20%) . Only a few resistant strains were found for cephalothin (5,07%), polymyxin B (0,27%) and enrofloxacin (0,53%) . While 16,27% of all isolates were resistant to chloramphenicol, 100% of the pasteurella strains proved to be sensible to its structural analogon florfenicol . This is affirmed by the low minimal inhibitory concentrations (0,25-1,0 micrograms/ml) of this antibiotic.

FEMS Microbiol Lett, 1996 Apr 15, 138(1), 29 - 34
Adherence and invasive capacities of the fish pathogen Pasteurella piscicida; Magarinos B et al.; Pasteurella piscicida strains were weakly or moderately adherent to cell lines, the levels of attachment being variable depending on the cells employed . All the isolates exhibited the highest binding capacity to CHSE-214 cells . Adhesive capacities were affected by heat and sugars but not by proteinase K or by treatment with antisera raised against the lipopolysaccharides of P . piscicida, implicating components of glycoprotein(s) as ligands in the adhesion process . The isolates showed a great binding capacity to intestines from the marine fish hosts gilthead sea bream, sea bass and turbot, with values ranging from 10(4) to 10(5) bacteria/g . Although the P . piscicida strains showed a weak invasiveness in the poikilothermic cell lines employed as in vitro model, the bacteria remained viable inside the infected cells at least for 2 days . The invasion process was inhibited by cytochalasin D indicating the active participation of the host cytoskeleton in the internalization of P . piscicida.

Can J Vet Res, 1996 Apr, 60(2), 140 - 4
Effect of supplemental chromium on antibody responses of newly arrived feeder calves to vaccines and ovalbumin; Chang GX et al.; Two trials were conducted to investigate the effects of supplemental chromium (Cr) from organic sources (Cr chelate and high Cr yeast) on antibody responses of newly arrived feeder calves following vaccination with infectious bovine rhinotracheitis (IBR), para-influenza-3 (PI3), bovine respiratory syncytial virus (BRSV), bovine viral diarrhea (BVD) and Pasteurella haemolytica and ovalbumin (OVA) . Using cross bred steer calves purchased at sales in Ontario, vaccines and OVA were given on d 0 and 21 after arrival in the feedlot . Immune responses of calves were measured as serum specific antibody titres against all antigens on d 0 and 28 or d 35 . The anti-OVA antibody responses (trial 2) were further investigated by measuring antibody concentrations of calves weekly until d 55 after arrival in the feedlot . Supplemental Cr (0.14 ppm) from an amino acid-chelated source had no effect on antibody responses to IBR, P13 and BRSV, but enhanced (P < 0.05) antibody titres of calves in response to the BVD vaccine on d 28 or d 35 . Supplemental Cr from Cr yeast had no effect on antibody titres of calves to any vaccines . Chromium from both sources (trial 1 and 2) had no effect on antibody responses of calves following vaccination with P . haemolytica . However, supplemental Cr (0.75 ppm) from Cr yeast enhanced (P < 0.05) serum antibody responses of calves to OVA during the primary response (d 14) and secondary response (d 35) following immunization . These data confirmed our previous finding that supplemental Cr can enhance humoral immune response of market-transit stressed calves, but its enhancement on vaccine efficacy was antigen-dependent and variable.

Can J Vet Res, 1996 Apr, 60(2), 127 - 32
Evidence of bovine immunoglobulin G1 (IgG1) protease activity in partially purified culture supernate of Pasteurella haemolytica A1; Lee CW et al.; In the bovine respiratory tract, IgG1 is a major secretory immunoglobulin (Ig), and both IgG1 and IgG2 are believed to be important in defense against pneumonic pasteurellosis (shipping fever) in calves . Here we provide evidence for hydrolysis of IgG1 in the presence of partially purified culture supernate (ppCS) from the respiratory pathogen Pasteurella haemolytica A1 . Bovine IgG1 was hydrolysed sequentially into three distinct bands (approximately 39, 12, and 7 kDa respectively) . Furthermore, partial hydrolysis of bovine IgG2 was observed, but neither bovine IgA nor IgM were affected by incubation with ppCS . These findings suggest that the production of an IgG1-specific protease by P . haemolytica A1 may be a virulence mechanism contributing to the pathogenesis of bovine pneumonic pasteurellosis.

Can J Vet Res, 1996 Apr, 60(2), 121 - 6
The quantitation of turbinate atrophy in pigs to measure the severity of induced atrophic rhinitis; Gatlin CL et al.; The two-fold purpose of this study was to establish a useful image analysis technique for quantitation of turbinate atrophy and to determine an optimum bacterial dose for inducing atrophic rhinitis (AR) . Two morphometric analysis methods were compared to determine a turbinate area ratio (TAR) and a turbinate perimeter ratio (TPR); the ratios of turbinate area to total nostril area and of turbinate perimeter to total nostril perimeter, respectively . Our first image analysis method differed from Collins et al (1) in that we used direct image capture (digitalization) via a video camera and a Macintosh microcomputer, rather than photographs and a digitizer tablet . The tracing techniques were the same as those used by Collins et al . The second morphometric method was modified from the first by exclusion of dorsal turbinate when tracing the nostril area and directly tracing only the ventral turbinate to get a turbinate measurement without subtracting . Area and perimeter ratios, for both methods, were compared to conventional visual snout scores, ventral measurements, and to each other . The results of the two image analysis methods correlated well, both with each other and with the visual scores . Doses of Pasteurella multocida (Pm) at a constant level, and Bordetella bronchiseptica (Bb) at various concentrations, were administered to 36 Hampshire-Duroc F1 SPF pigs to determine the best dose and frequency for inducing AR . Although the dose selection may have been somewhat affected by the pre-existing presence of Bb, the optimal dose per naris in this study was 2 mL Bb at 10(7) cfu/mL combined with 2 mL Pm at 10(9) cfu/mL inoculum . The frequency of administration (1 x or 2 x) did not greatly affect results . Turbinate area ratio was the best tool for quantitating gross morphological turbinate changes associated with atrophic rhinitis in this study . Our simplified modification of Collins et al image analysis method (exclusion of dorsal turbinates and direct measurement of ventral turbinates) correlated well with visual scores, and, when compared to Collins et al method, required less data manipulation and labour.

Lab Anim, 1996 Apr, 30(2), 120 - 6
Enhancement of respiratory immunity to Pasteurella multocida by cholera toxin in rabbits; Suckow MA et al.; Cholera toxin (CT) is a potent adjuvant for the mucosal immune system . The purpose of this study was to determine if coadministration of CT with a potassium thiocyanate extract of Pasteurella multocida (PTE) leads to enhanced anti-PTE antibody activity and increased protection of rabbits against infection with P . multocida and associated disease . Groups of rabbits were immunized intranasally on days 0, 7, and 14, with phosphate buffered saline (PBS), 200 micrograms of CT, 1.0 mg of PTE, or 1.0 mg PTE with 200 micrograms CT . Nasal lavage and serum samples were collected over 28 days after initial immunization and evaluated by ELISA for specific antibody directed against PTE . Marked increases in serum (IgG) and nasal lavage (IgA) anti-PTE antibody activity were found beginning after day 14 in rabbits immunized with PTE . Rabbits immunized with PTE and CT demonstrated further increases in this activity . Tracheobronchial lavage samples collected at the time of necropsy demonstrated a significant level of anti-PTE IgA activity in animals immunized with PTE, and coadministration with CT stimulated a further significant increase in this activity . Groups of similarly immunized rabbits were challenged 16 days after initial immunization with 5 x 10(7) CFUs of P . multocida . Nasal lavage samples were cultured for P . multocida over the next 10 days . Rabbits were euthanized within 10 days after challenge, tissues cultured for P . multocida, and histopathologic lesion severity graded using a numeric scale . Rabbits immunized with PTE survived longer, had less severe lesions of the lungs, pleura, and liver, and fewer P . multocida CFUs cultured from samples than PBS or CT controls . Coadministration of CT led to further reductions in lesion severity of those tissues and numbers of P . multocida CFUs cultured from samples . Increased nasal turbinate atrophy of rabbits immunized with PTE with or without CT was associated with increased mean survival time . In summary, coadministration of CT with PTE enhanced protective immunity to P . multocida disease and infection in rabbits.

Microb Pathog, 1996 Apr, 20(4), 203 - 12
Molecular cloning and expression of bovine interleukin-8; Morsey MA et al.; Interleukin-8 (IL-8) is a neutrophil and T-lymphocyte chemotactic and activating factor . This cytokine is produced by many cell types including macrophages in response to a variety of microbial and non-microbial agents . In the present study, we determined the nucleotide sequence for bovine IL-8 cDNA . The amino acid sequence encoded by this cDNA shares 76 and 87% homology with the human and swine IL-8 proteins, respectively . Bovine IL-8 cDNA was expressed in Escherichia coli as a beta-galactosidase fusion protein . Western blotting demonstrates that this fusion protein, but not beta-galactosidase cross-reacts with monospecific anti-human IL-8 antiserum . We also studied the induction of IL-8 mRNA synthesis in bovine alveolar macrophages (BAM) stimulated with heat-killed Pasteurella haemolytica . IL-8 mRNA was induced in BAM as early as 1 h and was detectable at high levels 12 h post-stimulation with P . haemolytica . A dose titration of P . haemolytica and E . coli endotoxins showed that a relatively low level of P . haemolytica endotoxin induced high levels of bovine IL-8 mRNA . The significance of these findings in the pathogenesis of bovine pneumonia caused by P . haemolytica is discussed.

Vet Microbiol, 1996 Apr, 49(3-4), 181 - 95
Comparative evaluation of antibodies induced by commercial Pasteurella haemolytica vaccines using solid phase immunoassays; Srinand S et al.; The objective of this study was to evaluate the ability of four commercial vaccines to elicit antibodies against the leukotoxin (Lkt), capsular polysaccharide (CP), iron regulated outer membrane proteins (IROMPs), and whole cell (WC) antigens of Pasteurella haemolytica A1 . Modified double antibody sandwich enzyme linked immunosorbent assays (ELISAs) were developed to measure antibody levels against Lkt, CP and IROMPs . An indirect ELISA was developed to measure the levels of antibody against WC antigens . The ideal cut off points for ELISAs were determined on receiver operating characteristic curves, using sera from 30 calves injected subcutaneously with a live P . haemolytica 12296 strain as positive control and sera from 30 colostrum-deprived calves as negative control . The vaccines evaluated were: 'One Shot' (SmithKline Beecham, West Chester, PA) a bacterin-toxoid, 'Presponse' (Langford Laboratories, Guelph, Ontario) a Lkt-rich culture supermatant, 'Once PMH' (BioCor Inc., Omaha, NE) a modified live vaccine, and 'Septimune' (Fort Dodge laboratories, Fort Dodge, IA) an outer membrane extract . Thirty, 4-6 week old Holstein calves were randomized into 5 groups to receive one of the four vaccines or a placebo (sterile phosphate buffered saline) . The calves were vaccinated intramuscularly on day 0 and on day 14, and bled on days, 0, 14, and 28 to measure antibody levels against Lkt, CP, IROMPs, and WC antigens of P . haemolytica Al . 'One Shot', and 'Once PMH' vaccinates showed a significant (P < 0.05) increase in antibody levels against Lkt at 28 days . 'Once PMH' vaccinates also showed significant (P < 0.05) increase in antibody levels against IROMPs at 28 days compared to the other four groups but this increase was not significant over time within the 'Once PMH' group . 'Presponse', 'Once PMH' and 'One Shot' vaccinates showed a significant (P < 0.05) increase in antibody levels against CP over time . These groups also had significantly higher antibody levels against CP, compared to controls and 'Septimune' vaccinates at 14 and 28 days (P < 0.05).

Lab Anim Sci, 1996 Apr, 46(2), 174 - 8
Evaluation of cecal ligation as a model of mucoid enteropathy in specific-pathogen-free rabbits; Hotchkiss CE et al.; Mucoid enteropathy is a serious disease of rabbits, the cause of which is unknown . Ligation of the cecum has been reported to cause a mucoid enteropathy-like syndrome in 70% of conventional rabbits . The goal of this study was to evaluate this model of mucoid enteropathy in Pasteurella-free, coccidia-free rabbits for use in future studies . Five rabbits served as unoperated controls (group 1) . Eight rabbits underwent ligation of the cecum, with large vessels and nerves spared (group 2) . In six rabbits the distal branch of the ileocecocolic vessels and nerve were incorporated into the cecal ligature (group 3) . At necropsy 3 to 5 days after surgery, all group-3 rabbits had copious amounts of clear, gelatinous mucus in the colon . Only one group-2 rabbit had grossly evident mucus hypersecretion, whereas none of the group-1 rabbits did . Group-3 rabbits had areas of necrosis in the cecum; this was not seen in group-1 or group-2 rabbits . Rabbits of groups 2 and 3 had inflammation of the distal portion of the colon . In specific-pathogen-free rabbits cecal ligation alone did not reliably stimulate mucus hypersecretion but induced a disease similar to natural mucoid enteropathy . Cecal ligation including vessels provided a reproducible syndrome of mucus hypersecretion; however, the severe cecal necrosis was not consistent with the naturally acquired disease.

J Wildl Dis, 1996 Apr, 32(2), 322 - 5
Isolation of Pasteurella spp . from free-ranging American bison (Bison bison); Taylor SK et al.; From November 1991 through March 1992, nasal and pharyngeal swab samples were collected from 45 bison (Bison bison) from Yellowstone National Park, Montana (USA) and cultured for Pasteurella spp . Thirteen isolates of Pasteurella spp . were recovered from 10 (22%) of the animals . Ten isolates were from pharyngeal samples in contrast to three isolates from nasal samples . Pasteurella haemolytica (six biotype T, two biotype A, and two biotype 3) was the predominant Pasteurella species . Five biotype T isolates were serotype 4 and the sixth agglutinated in antisera 3, 4, and 10 . Both biotype A isolates were untypable with antisera to recognized type strains . Pasteurella multocida was isolated from the pharyngeal samples of one animal . Two isolates could not be identified to species.

J Wildl Dis, 1996 Apr, 32(2), 315 - 21
Attempted protection of bighorn sheep (Ovis canadensis) from pneumonia using a nonlethal cytotoxic strain of Pasteurella haemolytica, biotype A, serotype; Foreyt WJ et al.; Between February and April, 1994, we tested the hypothesis that bighorn sheep (Ovis canadensis canadensis) inoculated with a cytotoxic isolate of Pasteurella haemolytica biotype A, serotype 11 (A11) could withstand challenge inoculation with a cytotoxic strain of P . haemolytica A2 of domestic sheep origin known to cause lethal pneumonia in bighorn sheep . On experimental day O, two bighorn sheep were inoculated intratracheally with 6 x 10(9) colony forming units (cfu) of a cytotoxic strain of P . haemolytica A11 (group 1); two bighorn sheep were inoculated intratracheally with 6 x 10(9) cfu of a noncytotoxic P . haemolytica A11 (group 2), and two control bighorn sheep were inoculated intratracheally with a similar volume of brain heart infusion (BHI) broth (group 3) . After inoculation, all bighorn sheep remained healthy . On experimental day 16, group 1 bighorn sheep each were given the same intratracheal inoculation as on day O, and groups 2 and 3 bighorn sheep each were inoculated with BHI broth at the same volume as group 1 . All bighorn sheep remained healthy following inoculations . On experimental day 42, bighorn sheep in groups 1 and 3 each were challenged with an intratracheal inoculation of 6 x 10(9) cfu of P . haemolytica A2 of domestic sheep origin known to be lethal in bighorn sheep . Group 2 sheep each were inoculated intratracheally with BHI broth at the same volume as groups 1 and 3 . The four bighorn sheep in groups 1 and 3 that received the challenge inoculation died from acute bronchopneumonia within 72 hours after challenge inoculation, and cytotoxic P . haemolytica A2 was isolated from the four dead bighorn sheep . Both cytotoxic or noncytotoxic strains of P . haemolytica A11 were not lethal and did not cause pneumonia in the experimentally inoculated bighorn sheep . However, previous inoculation with cytotoxic P . haemolytica A11 did not protect the bighorn sheep against later experimental challenge inoculation with a known lethal strain of cytotoxic P . haemolytica A2 under the conditions defined in these experiments.

Chest, 1996 Apr, 109(4), 1043 - 8
Serial pleural fluid analysis in a new experimental model of empyema; Sasse SA et al.; Prior attempts to create an animal model of empyema by direct inoculation of bacteria alone into the pleural space have been unsuccessful . The animals either died of overwhelming sepsis or cleared the infection from the pleural space without development of an empyema . We hypothesized that injection of bacteria with a nutrient agar into the pleural space would allow the bacteria to remain in the pleural space for an extended time period, permitting an empyema to develop . The bacterium Pasteurella multocida in brain heart infusion (BHI) agar was injected into the right hemithorax of 12 New Zealand white male rabbits . Our preliminary studies showed that the animals died in less than 7 days if they were not given parenteral antibiotics . For this reason, the rabbits were given penicillin, 200,000 U, IM, every 24 h starting 24 h after bacterial injection . Pleural fluid was sampled by thoracentesis at 12, 24, 48, 72, and 96 h after bacterial injection . Pleural fluid pH, glucose, lactate dehydrogenase (LDH), leukocyte count, and Gram's stain and culture (in one half of the animals) were obtained at each time point . Pleural biopsy specimens were obtained at autopsy after 96 h . The mean pleural fluid pH reached a nadir of 7.01 at 24 h and remained less than 7.1 throughout the experiment . The mean pleural fluid glucose level reached a nadir of 10 mg/dL at 24 h . The mean pleural fluid LDH peaked at 21,000 IU/L at 24 h and the mean pleural fluid leukocyte count peaked at 12 h with a value of 67,000 cells per cubic millimeter . Gram's stains revealed organisms and cultures were positive for growth in all animals at 12 and 24 h . Some animals had positive Gram's stains and growth on cultures up to 72 h after bacterial injection . At autopsy, all rabbits injected with bacteria had gross pus in the right pleural space and had developed a thick pleural peel . Microscopic specimens of the pleura revealed large numbers of leukocytes (primarily polymorphonuclear lymphocytes) with invasion of the adjacent lung and chest wall . In conclusion, this model more closely mimics the empyema that occurs in humans, relative to previous animal models . This model appears appropriate for additional randomized studies in which different methods for the treatment of empyema can be evaluated.

Infect Immun, 1996 Apr, 64(4), 1446 - 9
Characterization of neuraminidases produced by various serotypes of Pasteurella multocida; Straus DC et al.; Neuraminidases produced by 16 strains of Pasteurella multocida (serotypes 1 to 16) were characterized by molecular weight, substrate specificity, and antigenic identity . After growth in a chemically defined medium, stage I (lyophilized) culture supernatants were assayed for activity with N-acetylneuramin lactose, human alpha-1-acid glycoprotein, fetuin, colominic acid, and bovine submaxillary mucin . Neuraminidase produced by P . multocida A:3 was purified by a combination of salt fractionation, ion-exchange chromatography on DEAE-Sephacel, and gel filtration on Sephadex G-200 . Purified P . multocida A:3 neuraminidase was employed to immunize rabbits, and the resulting antiserum reduced the activity of the P . multocida A:3 enzyme by 40.3% . This antiserum also reduced the activities of the neuraminidases produced by other serotypes by between 30.8 and 59.6% . Molecular weight estimates of the neuraminidases produced by the various serotypes were obtained by gel filtration chromatography on Sephadex G-200 . Each of the 16 serotypes examined produced a neuraminidase with a molecular weight of approximately 500,000 . In addition, all 16 high-molecular-weight neuraminidases showed similar substrate specificities . On the basis of these data, it appears that the high-molecular-weight neuraminidases produced by different P . multocida serotypes are quite similar.

J Infect Dis, 1996 Apr, 173(4), 1034 - 7
Pneumocystis carinii infection in transgenic B cell-deficient mice; Marcotte H et al.; Pneumocystis carinii is an important cause of pneumonia in immunocompromised hosts . Both cellular and humoral immunity seem important in resistance to this pathogen, but the specific role of each component is poorly understood . An outbreak of P . carinii pneumonia in transgenic B cell-deficient mice (muMT) was studied . Over 4 months, >50% of 41 muMT/muMT mice maintained in a sterile environment died of pneumonia . Some mice had concurrent infection with Pasteurella pneumotropica . Homozygous muMT/muMT mice had no detectable serum immunoglobulins, while their heterozygous muMT/+ counterparts had normal levels of IgM, IgG, and IgA and did not develop pneumonia . The infection was controlled by treating the mice with trimethoprim-sulfamethoxazole, and the pathogen was eliminated by cesarean rederivation . These observations suggest an important role for B cells in the host defense against P . carinii.

Biochem Biophys Res Commun, 1996 Mar 7, 220(1), 141 - 6
The Pasteurella haemolytica O-sialoglycoprotein endopeptidase is inhibited by zinc ions and does not cleave fetuin; Cladman WM et al.; Culture supernatants of Pasteurella haemolytica A1 contain an O-sialoglycoprotein endopeptidase that cleaves human glycophorin A . This enzyme is inhibited by micromolar concentrations of Zn2+ . It can be separated from a neuraminidase activity in culture supernatants by ion-exchange chromatography . The neuraminidase activity can cause the de-sialation of the bovine soluble sialoglycoprotein, fetuin . However fetuin is not cleaved proteolytically either by culture supernatants from P . haemolytica A1 or by chromatographically purified O- sialoglycoprotein endopeptidase or neuraminidase.

Vet Immunol Immunopathol, 1996 Mar, 50(1-2), 67 - 77
Preparturient vaccination to enhance passive immunity to the capsular polysaccharide of Pasteurella haemolytica A1; Hodgins DC et al.; The potential to increase passive serum antibody titres to a polysaccharide antigen in neonates, by preparturient vaccination of the dams was investigated . Dairy cows in five private herds were vaccinated with a commercial Pasteurella haemolytica culture supernatant vaccine (Presponse, Langford Inc.), at 6 and 3 weeks before their calculated due dates . Dams' sera, colostral whey, and post-colostral calf sera were assayed for antibodies of the IgG1 isotype binding purified capsular polysaccharide of P . haemolytica A1, using an enzyme immunoassay . Antibody titres were analyzed using the General Linear Model procedure (Statistical Analysis Systems Institute Inc.) . Vaccinated dams had a significant increase in serum antibody titre after vaccination compared with non-vaccinates (P <0.01), and their antibody titres in colostral whey were significantly higher (P <0.05) . Calves of vaccinated dams had significantly higher passive antibody titres than those of non-vaccinates (P <0.01) in all herds.

Zentralbl Veterinarmed B, 1996 Mar, 43(1), 59 - 62
Pneumonic pasteurellosis associated with Pasteurella haemolytica in chipmunks (Tamias sibiricus); Astorga RJ et al.; A laboratory study was performed in order to identify the possible cause of death in chipmunks (Tamias sibiricus) imported from China with respiratory disease . Severe congestion, alveolar oedema and fibrinous pleuritis were observed . Biochemical analyses identified the causative organism as Pasteurella haemolytica . An in vitro susceptibility test using various antimicrobial agents revealed sensitivity to beta-lactams (ampicillin and amoxicillin) and streptomycin.

Zentralbl Veterinarmed B, 1996 Mar, 43(1), 45 - 53
Isolation and purification of functional bovine lung mast cells (BLMCs); Stahl J et al.; Purified pulmonary mast cells were obtained from bovine lung using a combination of enzymatic digestion of tissue, density gradient centrifugation using Percoll, and centrifugal elutriation . In the initial procedure, lung tissue was enzymatically digested with collagenase, hyaluronidase, protease and elastase in three 30 min incubations at 37 degrees C . Monodispersed cell suspensions contained between 2 and 6% mast cells . Further purification of these mast cells by Percoll gradients and elutriation consistently yielded mast cells of > 90% purity . These cells were morphologically intact, viable and functional, as determined by histamine release evoked by secretagogue challenge . Incubation of BLMCs with Pasteurella haemolytica A1 culture supernate containing leucotoxin (LCT) alone, resulted in increased histamine release compared to controls . LCT also potentiated calcium ionophore (CaI)-induced histamine release from BLMCs.

Microbiology, 1996 Mar, 142 ( Pt 3), 551 - 60
Intra-specific diversity within Pasteurella trehalosi based on variation of capsular polysaccharide, lipopolysaccharide and outer-membrane proteins; Davies RL et al.; Intra-specific diversity within Pasteurella trehalosi was investigated by analysis of variation of capsular polysaccharide, and lipopolysaccharide (LPS) and outer-membrane protein (OMP) profiles . Sixty isolates of P . trehalosi, from diverse geographical locations within the UK, were examined . Capsular polysaccharide serotypes were determined by indirect haemagglutination assay; LPS and OMP profiles were compared by SDS-PAGE analysis . Capsular serotyping identified three isolates of serotype T3, 18 isolates each of serotypes T4, T10 and T15, and three untypable (UT) isolates . Analysis of LPS and OMP profiles identified six smooth LPS types and four OMP types among the 60 isolates . Forty-five (75%) of the isolates belonged to a single OMP type whereas 52 (87%) of the isolates possessed one of three LPS types . Each typing method, by itself, was not very discriminating but when the data from the three methods were combined, the 60 isolates could be separated into 14 distinct subgroups containing from one to 16 isolates as follows: serotype T3, two subgroups; serotype T4, four subgroups; serotype T10, two subgroups; serotype T15, five subgroups; UT isolates, one subgroup . Certain subgroups were associated with only one serotype whereas other subgroups were common to two or more serotypes . The subgroupings were capable of differentiating between isolates of the same serotype from the same and different geographical origins . Based on their LPS and OMP profiles, isolates of serotypes T4 and T15 were more closely related to each other than to isolates of serotype T10; serotype T4 and T15 isolates were also more heterogeneous than those of serotype T10 . Certain isolates of serotype T10, recovered from a wide geographical area, were characterized by the possession of a unique capsule/LPS/OMP combination and represented a single clonal group which was responsible for a large proportion (31%) of recent disease outbreaks . Overall, a combination of capsular serotyping, and LPS and OMP typing, was found to be extremely useful for assessing diversity within P . trehalosi and should be of value for epidemiological and virulence studies.

Commun Dis Rep CDR Rev, 1996 Mar 1, 6(3), R46 - 9
Wild brown rats (Rattus norvegicus) as a zoonotic risk on farms in England and Wales; Webster JP; Fear of wild rats as carriers of disease is embedded within our culture . Surprisingly little is actually known about parasites in wild rat populations . In recent studies aimed to rectify this omission, farms in England and Wales were surveyed to identify parasite species present in the rat populations . Rats were found to be infected with numerous zoonotic parasites, including cryptosporidium, pasteurella {correction of pasturella}, listeria, yersinia, coxiella, and hantavirus . These findings suggest that wild brown rats represent a potential risk to the health of humans and domestic animals.

J Vet Med Sci, 1996 Mar, 58(3), 273 - 4
Isolation of obligate and facultative anaerobic bacteria from feline subcutaneous abscesses; Hoshuyama S et al.; A total of 113 specimens collected from purulent skin lesions of household cats was examined bacteriologically . Ninety seven isolates obtained from 74 specimens (65.5%) . Of these, 11 specimens (9.7%) contained obligate anaerobes only, 18 specimens (15.9%) yielded both obligate and facultative anaerobes . In the obligate anaerobes detected, genus Fusobacterium was the most frequently observed and F . nucleatum was most common species . Pasteurella multocida was the facultative anaerobe which was most frequently detected.

J Vet Med Sci, 1996 Mar, 58(3), 269 - 72
Outbreaks of fowl cholera in Muscovy ducks (Cairina moschata) on a farm in Aomori Prefecture; Takahashi S et al.; Outbreaks of a subacute disease characterized by lameness, corneal turbidity, dysstasia and depression occurred in Muscovy ducks (Cairina moschata) on a farm in Aomori Prefecture in February and May 1991 . Nine strains of Pasteurella multocida were isolated from 5 to 6 dead ducks, and 4 of 8 ducks with clinical signs . Serotypes of the isolates were identified as Heddleston's serotype 1, 10 or 12 and Namioka's serotypes 5:A, 8:A, 9:A or 9:UT . These isolates were highly susceptible to 12 antibiotics, although, some of them were considerably resistant to chloramphenicol . Mouse LD50 values of the 9 isolates ranged from 10(1.0) to 10(5.3) . The most virulent strain for the mouse killed 2 to 4 ducks when inoculated intramuscularly at a concentration of 10(3.3) . This is the first report of outbreaks of fowl cholera in Muscovy ducks infected with various serotypes strains of P . multocida in Japan.

Berl Munch Tierarztl Wochenschr, 1996 Mar, 109(3), 101 - 7
{Demonstration of pneumonia in swine as a constant problem: culture and immunofluorescence microscopic studies of bronchioalveolar lavage (BAL) and serological findings}; Runge M et al.; Bronchoalveolar lavage was performed in 128 pigs from five fattening units showing acute pneumonia (48 animals), subclinical purulent pneumonia (17 animals), and chronic purulent pneumonia (63 animals) . These samples were investigated for bacteria . Additionally immunofluorescence microscopy as well as serological investigations were performed to detect antibodies against several bacteria and viruses . Pasteurella multocida could be detected in more than a half of the samples of pigs with acute pneumonia . Bordetella bronchiseptica and mycoplasmas were isolated in a lower amount . Probably these bacteria infected the pigs of at least one herd after a primary infection with influenza virus because (i) influenza virus could be detected in three of four animals investigated for influenza virus by culture methods, (ii) the virus could be detected in one third of the animals investigated for by immunofluorescence microscopy, and (iii) antibodies against influenza virus could be detected in almost all animals . From pigs with subclinical purulent pneumonia Bordetella bronchiseptica as the only bacterial lung pathogen could be isolated exclusively from nearly each sample . From the samples of pig suffering from chronic purulent pneumonia first of all Bordetella bronchiseptica, Pasteurella multocida and different mycoplasma species could be detected . Using cultural methods Actinobacillus pleuropneumoniae could be isolated from six samples only, in contrast to frequent positive reactions against Actinobacillus pleuropneumoniae antigens obtained by immunofluorescence microscopy and CFT.

Infect Immun, 1996 Mar, 64(3), 959 - 65
Pasteurella multocida toxin is a mitogen for bone cells in primary culture; Mullan PB et al.; The effect of recombinant Pasteurella multocida toxin (PMT) on primary cultures of embryonic chick bone-derived osteoblastic cells was investigated . It was found that PMT was a potent mitogen for primary derived chicken osteoblasts . The toxin stimulated DNA synthesis and cell proliferation in quiescent osteoblasts at the first passage and accelerated cell growth in subconfluent cultures . Cell viability was not affected by PMT, even at relatively high concentrations . Osteoblast numbers increased in a dose-dependent manner in response to PMT . Intracellular inositol phosphates were elevated in response to PMT, but no elevation in cyclic AMP (cAMP) levels was evident . Indeed, PMT inhibited cAMP elevation in osteoblasts in response to cholera toxin at a stage before other PMT-mediated events take place . In addition to increased cell turnover, PMT down-regulated the expression of several markers of osteoblast differentiation . Both alkaline phosphatase and type I collagen were reduced, but osteonectin was not affected . The in vitro deposition of mineral in cultures of primary osteoblasts and osteoblast-like osteosarcoma cells was also inhibited by the presence of PMT . This suggests that PMT interferes with differentiation at a preosteoblastic stage.

J Am Vet Med Assoc, 1996 Mar 1, 208(5), 711 - 5
Growth and microbial flora of nonmedicated, segregated, early weaned pigs from a commercial swine operation; Dritz SS et al.; OBJECTIVE--To determine whether segregated, early weaned pigs have better growth performance and different microbial flora than those pigs raised on-site . DESIGN--Prospective, observational study . ANIMALS--Pigs from a commercial operation that were known to be infected with several common swine pathogens . PROCEDURE--Pigs (7 to 10 days old) were weaned and segregated from the farm of origin and compared with littermate control pigs (14 to 17 days old) that were weaned and raised on-site . Pig weight was measured and microbial flora were isolated at 14-day intervals for 84 days, beginning when the pigs were 7 to 10 days old . RESULTS--At 50 days of age, the segregated, early weaned pigs had a mean weight of 23.7 kg, compared with a mean weight of 12.5 kg for control pigs . Pasteurella multocida was isolated from fewer segregated, early weaned pigs than from controls . Signs of Mycoplasma hyopneumoniae infection were detected in control pigs but not in segregated early weaned pigs . Clinical, serologic, or bacteriologic signs of early postnatal vertical transmission of Actinobacillus pleuropneumoniae were not detected in either group . CLINICAL IMPLICATION--Vertical transmission of M hyopneumoniae was prevented by weaning pigs at 7 to 10 days of age and segregating them off-site, without the use of medication . Although medicated controls were not compared, results from this herd revealed that use of antibiotics is not the most important factor for disease control in segregated, early weaning programs . Minimizing antibiotic use in disease-control protocols reduces costs as well as removes the need for extra-label drugs.

Vaccine, 1996 Feb, 14(2), 147 - 54
Evaluation of three experimental subunit vaccines against pneumonic pasteurellosis in cattle; Sreevatsan S et al.; The objective of this study was to evaluate the efficacy of three Pasteurella haemolytica A1 derived experimental subunit vaccines against pneumonic pasteurellosis in cattle . The three vaccines were: (a) culture supernatant (CS) containing leukotoxin (Lkt), lipopolysaccharide (LPS) and capsular polysaccharide (CP); (b) sodium salicylate extract (SSE) containing iron regulated outer membrane proteins (IROMPs), LPS and CP; (c) and a combination of the above two . Vaccine efficacy was defined in terms of reduction in clinical and pneumonic lesion scores after intrapulmonic challenge with live P . haemolytica . The results indicate that the CS vaccine elicited antibodies against both Lkt and CP, while the SSE vaccine elicited antibodies against IROMPs and CP . Animals inoculated with the combination vaccine showed increased levels of antibodies against IROMPs, Lkt and CP . There was significant correlation between lung and serum antibodies against Lkt, CP and IROMPs . Animals that received the combination vaccine had significantly lower mean pneumonic lung score as compared to SSE and control groups . The animals which received CS vaccine had mean pneumonic lung score significantly lower than that of control group . A strong negative correlation existed between serum antibody levels against Lkt, IROMPs, CP and pneumonic lung scores . The results from this study demonstrate the usefulness of CS vaccine alone or in combination with SSE vaccine in bringing about optimal protection in vaccinated calves, against experimental pneumonic pasteurellosis.

Comp Immunol Microbiol Infect Dis, 1996 Feb, 19(2), 99 - 115
Characterization of bovine pulmonary and serum antibody responses after parenteral or intrapulmonary vaccination with live Pasteurella haemolytica; McBride JW et al.; Pulmonary and serum antibody responses were evaluated in eight calves vaccinated {four intrapulmonary-right diaphragmatic lobe (IP) and four subcutaneous (SC)} with Pasteurella haemolytica A1 (Ph-1) impregnated agar beads and eight respective sham-vaccinated calves . Experimental and sham groups were challenged in both diaphragmatic lobes with Ph-1 34-37 d after vaccination (DAV) and necropsied 6 d after challenge (DAC; 40-43 DAV) . IgG antibodies contained in fluids from the diaphragmatic lobes of vaccinated calves had different patterns of antigen specificity compared with IgG antibodies in analogous sera . Using ELISA, anti-Ph-1 IgA and IgG antibody concentrations were significantly higher (P < 0.05) in lung lavage fluids from the IP group before and after challenge compared to the SC and sham groups . The IP and SC groups developed IgA, IgG and IgM antibody titers in nonvaccinated lung lobes after vaccination and challenge . The IP and SC groups exhibited significantly (P < 0.05) smaller pulmonary lesions than the sham groups and pulmonary IgG and IgA antibodies were associated with increased protection.

J Clin Microbiol, 1996 Feb, 34(2), 393 - 7
Coagglutination test for serotyping Pasteurella haemolytica; Fodor L et al.; A coagglutination test was described for simple, fast, and reliable detection of Pasteurella haemolytica type-specific antigens in lung lesions even in the absence of viable P . haemolytica . The coagglutinating reagents were prepared by coating protein A-producing Staphylococcus aureus cells with hyperimmune sera raised against P . haemolytica type strains . Bacterial suspensions, saline extracts, and boiled saline extracts of the bacteria were used as antigens . Homologous reactions with all types of antigens were precise . Some cross-reactions were similar to those obtained by the indirect hemagglutination test, and some additional one-way cross-reactions were identified . The coagglutination test was used for serotyping 65 P . haemolytica field strains and for the detection of P . haemolytica type-specific antigens in the lung specimens of 62 calves and 78 sheep . Ninety-four percent of the field strains could be serotyped by the coagglutination test . P . haemolytica type-specific antigens were detected in the lung specimens of 3 calves and 5 sheep that had succumbed to naturally occurring P . haemolytica pneumonia and in the lungs of 20 calves experimentally infected with P . haemolytica A1 . The coagglutination test detected type-specific antigens in 36% of the lung specimens of slaughtered field sheep but not in the lungs of slaughtered field cattle with small chronic lung lesions . No reaction occurred in the case of nonpneumonic calves and sheep or when pneumonic lesions were caused by other bacteria . No P . haemolytica strains could be isolated from lung samples that were coagglutination test negative . This test is recommended as an additional method for fast and reliable serotyping of P . haemolytica.

Lab Anim Sci, 1996 Feb, 46(1), 81 - 5
Detection of Pasteurella pneumotropica in laboratory mice and rats by polymerase chain reaction; Wang RF et al.; A 16S rDNA-based polymerase chain reaction (PCR) method specific for Pasteurella pneumotropica was developed . The PCR product, a 395-base pair DNA fragment, was amplified from P . pneumotropica and not from 42 other bacterial species tested, including four other Pasteurella species and Actinobacillus ureae . The PCR method was used to identify 13 previously isolated strains that had been identified as P . pneumotropica by conventional methods: 12 were confirmed by PCR; one that was PCR-negative was re-examined by biochemical methods and determined to be A . ureae . The PCR detection of P . pneumotropica in nasopharyngeal swab specimens from 121 surveillance animals (15 inbred mice and 5 inbred rats from 20 animal rooms) had a high carrier state in healthy laboratory animals; for example, rat swab specimens were 89.6% (43/48) positive by PCR, 8.3% were positive by the direct culture-biochemical method, and 16.7% were positive by the enrichment culture-biochemical method . The positive rate for mice (21.9% {16/73}) was lower than that for rats.

Am J Vet Res, 1996 Feb, 57(2), 224 - 8
Clinical field trials with tilmicosin phosphate in feed for the control of naturally acquired pneumonia caused by Actinobacillus pleuropneumoniae and Pasteurella multocida in swine; Moore GM et al.; OBJECTIVE--To determine and evaluate the efficacy of the dose range of tilmicosin phosphate fed to pigs for control of pneumonia attributable to Actinobacillus pleuropneumoniae during episodes of clinical disease in commercial herds . DESIGN--12 trials were run in 9 geographic locations in herds with a history of pneumonia caused by A pleuropneumoniae . ANIMALS--Clinically normal male and female pigs of various body weights . PROCEDURE--Two doses of tilmicosin phosphate (200 and 400 micrograms/g) and a 0 dose were administered in the feed for 21 days . Variables for determining efficacy were daily independent composite clinical impression score, individual pig weight, mortality, percentage of pneumonic involvement, and frequency of isolation of bacterial pathogens . RESULTS--Medicated pigs had significantly lower mortality attributed to pneumonia than did nonmedicated pigs . In trials with confirmed pneumonia caused by A pleuropneumoniae or Pasteurella multocida, weight gain, feed conversion, and clinical impression scores were significantly improved in the pigs receiving 200 or 400 micrograms/g of tilmicosin, compared with nonmedicated pigs . CONCLUSIONS--The clinical field trials reported here confirm that tilmicosin in the feed at 200 micrograms/g is effective for control of swine pneumonia attributable to A pleuropneumoniae or P multocida . CLINICAL RELEVANCE--Under the moderate natural challenge conditions encountered, tilmicosin at 400 micrograms/g was not different from tilmicosin at 200 micrograms/g.

J Biotechnol, 1996 Jan 26, 44(1-3), 139 - 44
Immunity and vaccine development in Pasteurella multocida infections; Adler B et al.; The role of LPS in immunity was studied using monoclonal antibodies (MAbs) and active immunisation experiments . A panel of six MAbs produced against Pasteurella multocida serotype B:2 reacted with the LPS of serotypes B:2 and B:5, but not with other serotypes . The MAbs could opsonise P . multocida for phagocytosis by mouse macrophages, but were not bactericidal in the presence of complement . They conferred only partial passive protection in mice . Similar results showing only partial protection were obtained when purified LPS was used to actively immunise mice prior to challenge, suggesting that LPS plays a partial role in immunity to infection . The aroA gene from P . multocida serotypes A:1 and A:3 was cloned and inactivated by insertion of a kanamycin resistance gene . The mutated gene was re-introduced onto the chromosome by allelic exchange . The resultant aroA mutants were highly attenuated in a mouse model system, with a 6-log decrease in ID50 . Virulence could be restored by complementation with a functional aroA gene . Mice immunised with two doses of the live mutants were protected against lethal challenge with the homologous parental strain, but not against the heterologous strain . P . multocida A:1 and A:3 expressed unique proteins when grown in iron-restricted medium . Moreover, the outer membrane (OM) fractions of these cells contained novel proteins of 75 kDa, 85 kDa and 94 kDa molecular mass . Mice were immunised with OM fractions prepared from serotype A:3 grown in iron-restricted (OM Fe-) or iron-replete (OM Fe+) media . When low challenge doses were used, both immunogens protected mice against serotype A:3, but only the OM Fe- fraction protected mice against heterologous challenge with serotype A:1 . When higher challenge doses were used, only partial protection was observed.

Proc Natl Acad Sci U S A, 1996 Jan 9, 93(1), 412 - 6
Isolation of an ovine pulmonary surfactant-associated anionic peptide bactericidal for Pasteurella haemolytica; Brogden KA et al.; Ovine pulmonary surfactant is bactericidal for Pasteurella haemolytica when surfactant and bacteria mixtures are incubated with normal ovine serum . To isolate this component, surfactant (1 mg/ml) was centrifuged at 100,000 x gav, and the supernatant was fractionated by HPLC . Fractions were eluted with acetonitrile (10-100%)/0.1% trifluoracetic acid and tested for bactericidal activity . Amino acid and sequence analysis of three bactericidal fractions showed that fraction 2 contained H-GDDDDDD-OH, fraction 3 contained H-DDDDDDD-OH, and fraction 6 contained H-GADDDDD-OH . Peptides in 0.14 M NaCl/10 microM ZnCl2 (zinc saline solution) induced killing of P . haemolytica and other bacteria comparable to defensins and beta-defensins {minimal bactericidal concentration (MBC)50 range, 0.01-0.06 mM} but not in 0.14 M NaCl/10 mM sodium phosphate buffer, pH 7.2/0.5 mM CaCl2/0.15 mM MgCl2 (MBC50 range, 2.8-11.5 mM) . Bactericidal activity resided in the core aspartate hexapeptide homopolymeric region, and MBC50 values of aspartate dipeptide-to-heptapeptide homopolymers were inversely proportional to the number of aspartate residues in the peptide . P . haemolytica incubated with H-DDDDDD-OH in zinc saline solution was killed within 30 min . Ultrastructurally, cells contained flocculated intracellular constituents . In contrast to cationic defensins and beta-defensins, surfactant-associated anionic peptides are smaller in size, opposite in charge, and are bactericidal in zinc saline solution . They are members of another class of peptide antibiotics containing aspartate, which when present in pulmonary secretions may help clear bacteria as a part of the innate pulmonary defense system.

J Biol Chem, 1996 Jan 5, 271(1), 439 - 45
Pasteurella multocida toxin, a potent intracellularly acting mitogen, induces p125FAK and paxillin tyrosine phosphorylation, actin stress fiber formation, and focal contact assembly in Swiss 3T3 cells; Lacerda HM et al.; Treatment of Swiss 3T3 cells with recombinant Pasteurella multocida toxin (rPMT), a potent intracellularly acting mitogen, stimulated tyrosine phosphorylation of multiple substrates including bands of M(r) 110,000-130,000 and M(r) 70,000-80,000 . Tyrosine phosphorylation induced by rPMT occurred after a pronounced lag period (1 h) and was blocked by either lysosomotrophic agents or incubation at 22 degrees C . Focal adhesion kinase (p125FAK) and paxillin are prominent substrates for rPMT-stimulated tyrosine phosphorylation . Tyrosine phosphorylation by rPMT could be dissociated from both protein kinase C activation and the mobilization of calcium from intracellular stores . rPMT stimulated striking actin stress fiber formation and focal adhesion assembly in Swiss 3T3 cells . Cytochalasin D, which disrupts the actin cytoskeleton, completely inhibited rPMT-induced tyrosine phosphorylation . In addition, tyrosine phosphorylation of p125FAK and paxillin in response to rPMT was completely abolished when cells were subsequently treated with platelet-derived growth factor at a concentration (30 ng/ml) that disrupted the actin cytoskeleton . Our results demonstrate for the first time that rPMT, a bacterial toxin, induces tyrosine phosphorylation of p125FAK and paxillin and promotes actin stress fiber formation and focal adhesion assembly in Swiss 3T3 cells.

Scand J Infect Dis, 1996, 28(1), 95 - 7
Pasteurella multocida endocarditis: report of a case and review of the literature; Genne D et al.; We report on a cirrhotic patient who presented with an aortic valve endocarditis due to Pasteurella multocida . This disease entity is rare and we take this opportunity to review the 6 cases published to date.

Scand J Infect Dis, 1996, 28(6), 567 - 70
Pasteurella aerogenes isolated from ulcers or wounds in humans with occupational exposure to pigs: a report of 7 Danish cases; Ejlertsen T et al.; Pasteurella aerogenes is rarely isolated from human specimens . The species is found in the digestive tract of pigs . From 1976 to 1994 7 strains were cultured in Denmark from wounds or ulcers . Five patients were bitten by pigs and 2 patients with ulcers were employed in pig farming . A mixture of bacterial species was often found . All 7 strains of P . aerogenes were susceptible to ampicillin, cephalosporins and ciprofloxacin . Ability to hydrolyse urea, to produce oxidase and catalase, to decarboxylate ornithine and to produce gas from glucose and inability to produce indole was characteristic for P . aerogenes . Most bite wounds were located on the lower lateral part of the thigh . Foul smelling pus and abscess formation was the rule . Incision, drainage and antibiotic treatment were usually necessary.

Acta Vet Hung, 1996, 44(3), 287 - 93
Mycoplasmal pneumonia in pigs in Croatia: first evaluation of a vaccine in fattening pigs; Bilic V et al.; The immunoprophylaxis of mycoplasmal pneumonia of swine (MPS) caused by Mycoplasma hypopneumoniae was investigated for the first time in fattening pigs in Croatia . The incidence of MPS was monitored in pigs weighing on average 27.5 kg (12 weeks old) after immunization with a M . hyopneumoniae vaccine . Of 350 pigs in each group, in the nonvaccinated group 55 animals (15.7%) were affected by pneumonia and 11 (3.1%) died of consequences of pneumonia, whereas in the vaccinated group 20 pigs (5.7%) were affected by pneumonia without any death due to the infection . In the nonvaccinated group 44% more pigs were individually treated with antibiotic, and these animals received in-feed therapy for more than 1/4 of the fattening period . Vaccinated pigs gained weight faster, at the rate of 0.745 kg/day (or 82 g/day more) than control animals . The mean score of lung lesions due to M . hyopneumoniae was 10.51 in the control pigs and only 0.54 in the vaccinated animals . The total tissue alterations on lungs due to M . hyopneumoniae, Pasteurella multocida and/or Actinobacillus pleuropneumoniae expressed as the mean-score were 13.21 in the control group and 2.98 in the vaccinated group . According to the results of evaluation of the M . hyopneumoniae vaccine in the field, the vaccine appeared to provide an adequate immunity in fattening pigs but was less effective when administered to younger pigs at 1-3 weeks of age.

Rev Elev Med Vet Pays Trop, 1996, 49(2), 98 - 101
{Epizootics of pasteurellosis in a semi-intensive breeding farm of indigenous rabbits in Senegal}; Dehoux JP et al.; Epizootic pasteurellosis appeared in a semi-intensive breeding farm (200 animals) of indigenous rabbits in Thies (ENSA), Senegal, during the 1995 wet season (August to October) . It provoked death in 87 animals . Young animals were particularly sensitive to the disease . Nasal discharge, conjunctivitis, eye loss and otitis media and interna were observed in young rabbits while posterior paresis was noted in mature rabbits . Pasteurella multocida, Klebsiella pneumoniae and Pseudomonas aerogenes were identified . An antibiogram revealed the germs were sensitive to chloramphenicol, sulfamethoxazole/trimethoprim and colistin . High temperatures and humidity during the wet season may have contributed to the outbreak of the disease from healthy carriers introduced at the founding of the farm . Colistin and chloramphenicol treatments were administered before vaccinating all rabbits against pasteurellosis.

J Biomater Sci Polym Ed, 1996, 8(2), 131 - 9
Oral immunization of rabbits against Pasteurella multocida with an alginate microsphere delivery system; Suckow MA et al.; Oral delivery of microencapsulated antigens is a potential means to vaccinate rabbits against Pasteurella multocida, a common bacterial pathogen . Groups of five rabbits were dosed orally on days 0, 7, and 14 with alginate microspheres prepared to contain no added protein, 5 mg of a potassium thiocyanate extract of P . multocida (PTE), or 5 mg of PTE with 200 micrograms of cholera toxin (CT) . In addition, groups were dosed orally with 5 mg of soluble PTE with or without 200 micrograms CT, intranasally (IN) with 1 mg of soluble PTE, or with saline . Serum and nasal lavage samples collected prior to initial immunization and 10, 16, and 21 days later were assayed by ELISA for anti-PTE IgG and IgA . Strong nasal lavage IgA and serum IgG activities were found in samples from rabbits immunized with PTE IN or orally when incorporated into microspheres . Addition of CT did not significantly enhance either response . To examine the development of protective immunity, groups were similarly immunized and challenge-exposed IN on day 16 with 10(6) CFU of P . multocida . One week later, rabbits were euthanized, and specimens from the lungs, nasopharynx, liver, and inner ear were cultured for P . multocida . Less severe infections of the lung and nasopharynx developed in rabbits immunized with PTE IN or orally in microspheres, with or without added CT . In addition, culture of liver and tympanic bullae samples from these rabbits yielded growth of P . multocida less frequently compared to other P . multocida-challenged rabbits . Coadministration of CT and PTE did not significantly improve protective immunity to challenge.

Vet Res Commun, 1996, 20(6), 519 - 31
In vitro expression and inhibition of procoagulant activity produced by bovine alveolar macrophages and peripheral blood cells; Rashid J et al.; Local and systemic activation of coagulation is frequently associated with bacterial sepsis . The coagulopathy is due, at least in part, to expression of tissue factor (TF) by monocytes and macrophages . The purpose of this study was to evaluate the expression of procoagulant activity by bovine alveolar macrophages, leukocytes and platelets, and to determine the relative potency of three chemical inhibitors of TF expression (pentoxifylline, retinoic acid, and cyclosporin A) . Bovine alveolar macrophages were stimulated with lipopolysaccharide (LPS) derived from Pasteurella haemolytica or recombinant bovine tumour nervous factor (TNF) and dose- and time-dependent effects on TF expression were studied . LPS and TNF induced TF expression in alveolar macrophages and LPS treatment of whole blood induced TF expression in mononuclear cells . Neutrophils and platelets also expressed procoagulant activity, but this activity was not inhibited by anti-bovine TF monoclonal antibody . Pentoxifylline (40 mumol/L), retinoic acid (0.01 mmol/L) and cyclosporin A (0.08 mumol/L) inhibited TF expression when added concurrently with LPS or TNF, but not when added 4 h after stimulation . TF mRNA was not detected in unstimulated alveolar macrophages by Northern blot analysis . In contrast, exposure to LPS or TNF for 6 h induced marked expression of TF mRNA, which was inhibited by treatment with pentoxifylline, retinoic acid and cyclosporin A . Expression of TNF by alveolar macrophages stimulated with LPS was also inhibited by these compounds . Our results indicate that procoagulant activity expressed by alveolar macrophages and monocytes is associated with expression of TF, whereas procoagulant activity expressed by neutrophils and platelets is not . The concentrations of pentoxifylline and retinoic acid necessary for inhibition of TF expression in vitro may not be achievable in vivo owing to their toxic effects . However, the in vitro concentration of cyclosporin A that inhibited TF expression did not exceed the plasma concentration observed in humans, and therefore may be useful for inhibition of TF expression in vivo.

Microbiol Immunol, 1996, 40(9), 665 - 9
Sequence analysis of the florfenicol resistance gene encoded in the transferable R-plasmid of a fish pathogen, Pasteurella piscicida; Kim E et al.; The florfenicol resistance gene (pp-flo) derived from a transferable R-plasmid of Pasteurella piscicida consisted of 1,122 nucleotides, and the predicted amino acid sequence showed 47.4% identity to that of a non-enzymatic chloramphenicol resistance gene (cmlA) . The pp-flo gene was located in the downstream region of the sulfonamide resistance gene of the transferable R-plasmid.

Postepy Hig Med Dosw, 1996, 50(2), 173 - 90
{Cytolysins and homologous proteins produced by gram-negative bacteria . I . Hemolysis and leukotoxins of Escherichia coli, Bordetella pertussis, Pasteurella haemolytica and Actinobacillus sp}; Rozalski A; Cytolysins produced by Gram-negative bacteria belong to the pore forming bacterial proteins . A branch of these toxins represents RTX family of proteins . The RTX (repeats in toxin) family name has been proposed based on the common presence of tandem copies of a nine-amino acid repeat (L-X-G-G-X-G-(N/D)-D-X) . The paper presents the genetics, synthesis, secretion and cytolytic activity of these toxins.

Vet Pathol, 1996 Jan, 33(1), 74 - 6
Detection of Mycoplasma ovipneumoniae and Pasteurella haemolytica antigens by an immunoperoxidase technique in pneumonic ovine lungs; Haziroglu R et al.; Four hundred twenty pneumonic lungs from lambs were examined for Mycoplasma ovipneumoniae and Pasteurella haemolytica by an immunoperoxidase technique using an extravidin-biotin-peroxidase complex method in formalin-fixed, paraffin-embedded sections . Histologic examination of tissue sections revealed strong positive reactions in 60.9% and 68.3% of the lungs against M . ovipneumoniae and P . haemolytica, respectively . M . ovipneumoniae and P . haemolytica antigens were observed at the surface and/or within the epithelial cells, macrophages, leucocytes, and bronchiolar exudate . The location of M . ovipneumoniae in the cytoplasm of the epithelial cells and P . haemolytica in the neutrophils was detected immunohistochemically.

Can J Vet Res, 1996 Jan, 60(1), 34 - 9
Stimulation of osteoclast-like cell formation by Pasteurella multocida toxin from hemopoietic progenitor cells in mouse bone marrow cultures; Jutras I et al.; The effects of purified Pasteurella multocida toxin (PMT) on osteoclast formation from hemopoietic progenitor cells were studied using an in vitro system . Mononuclear adherent mouse bone marrow cells were cultured for 7 or 14 days in the presence of PMT, or 1,25-dihydroxy-vitamin D3, or both . Mononuclear osteoclast-like cells, which are postmitotic osteoclast precursor cells, were identified as tartrate-resistant acid phosphatase (TRAP)-positive mononuclear cells possessing calcitonin receptors . Multinucleated osteoclast-like cells were TRAP-positive multinuclear cells with calcitonin receptors . The results demonstrate that, as does 1,25(OH)2D3, Pasteurella multocida toxin stimulates proliferation of adherent bone marrow mononuclear cells (progenitor cells), and their differentiation into postmitotic mononuclear osteoclast precursor cells . It also causes fusion of the latter into multinuclear osteoclasts; however, the number of osteoclasts obtained with PMT is smaller than with 1,25-dihydroxy-vitamin D3.

Microbiol Immunol, 1996, 40(5), 397 - 9
Sulfonamide resistance gene in a transferable R plasmid of Pasteurella piscicida; Kim EH et al.; The sulfonamide resistance (SAr) determinant was cloned from a transferable R plasmid of Pasteurella piscicida, pSP9351, and the sequence was determined . The resistance gene (pp-sul) was localized to an approximately 1-kb region that includes the PstI-EcoRI site in the restriction map . An open reading frame coding a sul II-type gene composed of 810 nucleotides was identified . A direct repeat sequence was shown in the 5' flanking region of pp-sul, and a plasmid recombinational event may have occurred during the construction of pSP9351 . In the 3' flanking region of the gene, a sequence homologous to the 5' noncoding sequence of the trimethoprim resistance gene, dhfr IX was found.

Vet Res, 1996, 27(3), 241 - 53
{Comparison of the use of a vaccine and sequential antibiotic treatment in a herd infected with Mycoplasma hyopneumoniae}; Le Grand A et al.; The purpose of this study was to compare the efficacy of Mycoplasma hyopneumoniae vaccination with pulse medication in a pig herd chronically infected with Mycoplasma hyopneumoniae . Control groups of pigs were compared to vaccinated or treated groups . Medication and vaccination induced a significant reduction of pneumonia score (46.37% and 29.8% respectively, compared to 53.85% for control groups, p < 0.05) . The treatment did not induce a significant reduction of the mean range of lung lesions (3.75) compared to the control groups (4.25) . The mean range of lung lesions was significantly reduced by vaccine (3.06, p < 0.005) but not by treatment . Neither the medication nor the vaccination were able to clear M hyopneumoniae or Pasteurella multocida from lung tissue . In this herd, the vaccination had a beneficial effect on daily weight gain of pigs (695.9 g/day compared to 683.1 g/day for the control groups) . The improvement of the age at slaughtering was 1.3 days for treated groups and 2.4 days for vaccinated groups compared to control groups . The vaccination induced a significant improvement in muscle rate (57.05%) compared to control groups (56.41%, p < 0.05) and to treated groups (56.21%, p < 0.001) . In this herd infected with M hyopneumoniae, after allowing for treatment cost, manpower excepted, the increase in value was from -3 FF to -11 FF for the antibiotic treatment and +10.4 FF for the vaccination . From economical and medical points of view, the vaccination was preferable to the treatment under the conditions described in this study.

Vet Res Commun, 1996, 20(3), 195 - 204
Biochemical characterization of lipopolysaccharides extracted from a hydrophobic strain of Pasteurella multocida; Conrad RS et al.; Lipopolysaccharides were extracted from freeze-dried cells of Pasteurella multocida strain P-1581 (serotype 8) by the phenol-chloroform-petroleum ether method and biochemically analysed using standard procedures . The primary neutral sugars were glucose, galactose and heptose . No deoxy sugars were detected . Amino sugars included galactosamine, glucosamine and glucosamine-6-phosphate . 3-Deoxy-D-manno-2-octulosonic acid was present at a relatively low concentration . The analyses included identification and quantification of phosphate and alanine . The primary fatty acids and their approximate relative ratios were 3-hydroxytetradecanoate and tetradecanoate 2:1 . Tetradecanoic acid was bound almost exclusively by ester linkages . 3-Hydroxytetradecanoic acid was bound primarily by amide linkages, although significant numbers of ester-bound residues were noted . Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analyses indicated that the lipopolysaccharides were of low molecular weight.

Am J Nephrol, 1996, 16(4), 361 - 6
An interesting case of failed renal transplant complicated by a lymphocele infected with Pasteurella multocida and a review of the literature; Mayo RR et al.; Lymphoceles are a well-known complication of renal transplant surgery and can be asymptomatic or present with a variety of symptoms and complications . We describe a patient who presented with a Pasteurella multocida infection of a lymphocele which occurred 3 weeks after a course of penicillin for a cat bite and 10 months after a renal transplant nephrectomy . We also will review the incidence, predisposing factors, origin, symptomatology, diagnosis, complications, and treatments of post-renal transplant lymphoceles.

Avian Dis, 1996 Jan-Mar, 40(1), 99 - 102
A pathogenic challenge model for adult northern bobwhite (Colinus virginianus) using a vaccine strain of Pasteurella multocida type 3; Dabbert CB et al.; A pathogenic challenge model causing approximately 50% mortality was developed in adult Northern bobwhite (Colinus virginianus) using Avichol, a live vaccine containing the Clemson University (CU) strain of Pasteurella multocida Type 3 . A dose of 2300 or 3000 colony-forming units (CFU) of Avichol injected intramuscularly resulted in 30 to 75% mortality, whereas a dose of 230 CFU or less resulted in no mortality, and 58,720 CFU or more resulted in death in all birds challenged . Primary and secondary vaccination of Northern bobwhite with a formalinized anaculture of Avichol -derived P . multocida resulted in protection against challenge in three separate experiments . Dexamethasone treatment of birds during vaccination resulted in decreased protection against challenge exposure.

Avian Dis, 1996 Jan-Mar, 40(1), 56 - 62
Development of a polymerase chain reaction and a nonradioactive DNA probe for infectious laryngotracheitis virus; Abbas F et al.; The polymerase chain reaction (PCR) was developed using infectious laryngotracheitis virus (ILTV) primers made from a portion of the ILTV thymidine kinase gene . DNA from various ILTV field isolates, from the USDA challenge strain of ILTV, and from commercial ILTV vaccines was specifically amplified . No amplification occurred using template DNA from uninfected chicken-embryo liver cells (CELC), several nonavian alphaher-pesviruses, Mycoplasma gallisepticum, Mycoplasma synoviae, Pasteurella hemolytica, Escherichia coli, a group I avian adenovirus, fowl poxvirus, or a psittacid herpesvirus . The 647-base pair-amplified ILTV PCR product was labeled to create a nonradioactive, biotinylated DNA probe . Hybridization using the probe detected ILTV DNA . Both PCR and hybridization yielded positive results with ILTV DNA but not with the DNA of other pathogens . Hybridization was specific for ILTV using a stringent salt solution for a 30-min wash step or a somewhat less stringent salt solution for a 60-min wash step . However, slight hybridization occurred with CELC DNA when the less stringent salt solution was used in a 30-min wash step.

Exp Anim, 1996 Jan, 45(1), 33 - 8
Rederivation of mice by means of in vitro fertilization and embryo transfer; Suzuki H et al.; In vitro fertilization and embryo transfer were performed for rederivation of four strains of mice harbouring mouse hepatitis virus (MHV) and/or Pasteurella pneumotropica (P . pneumotropica) . Superovulated oocytes were fertilized by preincubated cauda epididymis sperm in vitro . Fertilized eggs at 2-cell stage were transferred into the oviducts of specific pathogen free (SPF) recipients . Microbial examination of sperm and/or oocyte donors verified the presence of P . pneumotropica and/or of antibodies to MHV in all strains, but neither in the recipients nor in the offspring antibodies to MHV could they be detected . The results indicate that an in vitro fertilization-embryo transfer (IVF-ET) system is an effective and simple alternative to cesarean operation in infected mice.

Poult Sci, 1996 Jan, 75(1), 29 - 33
The influence of major histocompatibility complex genotypes on resistance to Pasteurella multocida and Newcastle disease virus in turkeys; Nestor KE et al.; Sublines homozygous for each of four MHC haplotypes were developed from randombred control populations of turkeys and challenged with Pasteurella multocida (capsular serogroup a, somatic serotype 3, 4) at 6 wk of age or Newcastle disease virus (NDV; Texas GB strain) at 4 wk of age . In addition, individuals from a randombred control line (RBC2) and a subline (F) of RBC2 long-term selected for increased 16-wk BW were included in most of the challenge trials . The duration of the challenge trials was 2 wk for both organisms . Mortality following challenge with P . multocida or NDV was higher in the F line than in its randombred control . The MHC genotypes differed in mortality following exposure to both organisms but the rankings of the genotypes were not the same for P . multocida and NDV . The increased susceptibility of the F line to both organisms could not be explained by known changes in the frequency of the MHC haplotypes.

Microbiology, 1996 Jan, 142 ( Pt 1), 199 - 206
The 32 kDa major outer-membrane protein of Pasteurella multocida capsular serotype D; Vasfi Marandi M et al.; The major outer-membrane protein (MOMP) of Pasteurella multocida serotype D strain P210, with an apparent molecular mass of 32 kDa, was purified and characterized . The purification method involved selective extraction of MOMP with N-lauroylsarcosine and SDS, followed by immunoaffinity chromatography using a murine monoclonal antibody (mAb) . The N-terminal sequence and amino acid composition of the MOMP showed considerable similarity to other Gram-negative bacterial porins, notably to the 37 kDa MOMP (porin H) of P . multocida . Immunoelectron microscopy and colony blotting assays were used to demonstrate the surface localization of the 32 kDa MOMP on bacterial cells . The colony blotting assay provided a simple, sensitive and rapid screening method for visualizing accessibility of the antibody on the cells . In a Western blot assay, murine polyclonal hyperimmune serum against the purified 32 kDa MOMP recognized both serotype B and D strains bearing either a 32 kDa or a 37 kDa MOMP, whereas the mAb recognized only serotype D strains bearing a 32 kDa but not a 37 kDa MOMP . The present data indicate that the 32 kDa MOMPs of P . multocida are antigenically heterogeneous and possess both specific and cross-reacting epitopes . Detection of type-specific epitopes on the 32 kDa MOMP using an mAb may have potential implications regarding the feasibility of developing a serotyping system for P . multocida.

Microbiology, 1996 Jan, 142 ( Pt 1), 115 - 21
Identification of Pasteurella multocida tryptophan synthase beta-subunit by antisera against strain P1059; Jablonski PE et al.; Pasteurella multocida strain P1059 is a highly virulent bacterium which causes fowl cholera in turkeys and chickens . A genomic library of P . multocida P1059 DNA was constructed using pUC19, expressed in Escherichia coli DH5 alpha, and screened with chicken antisera generated against P . multocida P1059 . Twelve out of the 4100 clones screened were immunoreactive . Plasmids isolated from these twelve clones were transformed into E . coli CSR603 for maxicell analysis . Five proteins, with molecular masses of 34, 37, 43, 46 and 55 kDa, were expressed . Further work focused on the 43 kDa protein because it was expressed at levels detectable by SDS-PAGE and immunoblot analysis . The nucleotide sequence of the 1.8 kbp insert containing the gene encoding this protein was determined . The sequence contained three open reading frames (ORFs) . The first ORF (ORF1) did not appear to code for any known protein . The second ORF (ORF2) encoded a protein of 403 amino acids (43,662 Da) . The deduced amino acid sequence showed 77% identity (84% similarity) with the tryptophan synthase beta subunit (TrpB) of Salmonella typhimurium and Vibrio parahaemolyticus . The eight conserved regions of TrpB are observed in the P . multocida enzyme, including the conserved lysine (Lys-88) and consensus sequence (GGGSNA) implicated in pyridoxal phosphate binding . The expression and identity of the P . multocida TrpB were confirmed by complementation studies using E . coli W3110 tnaA2 trpB9578 . The third ORF (ORF3) consisted of the first 77 nucleotides of the gene encoding the alpha-subunit of tryptophan synthase (trpA), and overlapped the 3'-end of trpB by 14 nucleotides . The deduced amino acid sequence of the 77 nucleotides of the P . multocida TrpA had 68% identity (92% similarity) with the analogous region of TrpA from Klebsiella aerogenes (K . pneumoniae).

Infect Immun, 1996 Jan, 64(1), 83 - 90
Molecular characterization of a common 48-kilodalton outer membrane protein of Actinobacillus pleuropneumoniae; Cruz WT et al.; Previous studies have shown that a vaccine prepared from outer membranes of Actinobacillus pleuropneumoniae serotype 5 can elicit protective immunity in swine against challenge with either serotype 5 or serotype 1 . These results suggest the presence of common subcapsular surface antigens, such as outer membrane proteins, that contribute to cross-protective immunity . We have identified a 48-kDa outer membrane protein that is common to all 12 capsular serotypes of A . pleuropneumoniae but is not present in the outer membranes of related species of gram-negative swine pathogens . This protein is immunogenic in swine infected with either A . pleuropneumoniae serotype 5 or 1A, as well as in swine vaccinated with A . pleuropneumoniae serotype 5 outer membranes . This 48-kDa protein is readily detected in outer membranes produced by sucrose density gradient centrifugation, but it is sarcosyl soluble and therefore not found in outer membranes prepared by detergent treatment . The gene encoding the 48-kDa outer membrane protein has been cloned from A . pleuropneumoniae serotype 5 and and has been designated aopA, for Actinobacillus outer membrane protein A . The gene is 1,347 bp in length and encodes a protein, designated AopA, of 449 amino acids with a predicted molecular weight of 48,603 . Southern blot analysis under high-stringency conditions showed that strains of all 12 serotypes of A . pleuropneumoniae contain DNA homologous to this gene, as do strains of two closely related species, Actinobacillus suis and Pasteurella multocida . Whether antibodies against the AopA antigen contribute to cross-protective immunity against A . pleuropneumoniae infection remains to be determined.

Biochim Biophys Acta, 1995 Dec 14, 1245(3), 407 - 13
Isolation of a spermatozoa motility inhibiting factor from chicken seminal plasma with antibacterial property; Mohan J et al.; A 78-kDa spermatozoa motility inhibiting factor (SMIF) was purified from chicken (Gallus domesticus) seminal plasma by anion exchange (DE-53) followed by affinity chromatography on concanavalin A-Sepharose . The factor is thermostable and inhibited the spermatozoa motility in a dose dependent manner . In addition, SMIF inhibited the growth of gram negative bacteria, Pasteurella multocida but not gram positive Streptococcus equi . The factor lost its spermatozoa immobilizing property after treatment with trypsin, chymotrypsin or pepsin . The inhibition of SMIF by beta-mercaptoethanol suggest the involvement of disulfide bonds in its activity . Similarly, this property was lost in presence of chicken seminal plasma or incubating SMIF with anti-SMIF antibodies . Evidence is provided for the presence of a high molecular weight protein (> 100 kDa) in chicken seminal plasma that neutralizes the motility inhibiting property of SMIF . No significant decrease in spermatozoa ATP was observed in presence of SMIF suggesting that the loss of spermatozoa motility was due to factors other than depletion in cell's energy . Using anti-SMIF antibodies, a cross-reactive protein was identified in the blood, liver and reproductive tissues of chicken and the seminal plasma of cattle and buffalo . However, the cross-reactive protein failed to inhibit chicken spermatozoa motility . The significance of SMIF in chicken seminal plasma is discussed.

Vet Microbiol, 1995 Dec, 47(3-4), 287 - 94
Influence of chondroitinase on indirect hemagglutination titers and phagocytosis of Pasteurella multocida serogroups A, D and F; Rimler RB et al.; Capsules of Pasteurella multocida serogroups A, D and F contain mucopolysaccharides which block antigenic determinants and prevent phagocytosis . In this study, capsules of serogroup A, D and F strains of P . multocida were depolymerized by enzyme treatment . Capsule depolymerization of serogroup D and F strains with chondroitinase increased indirect hemagglutination (IHA) test titers and enhanced phagocytosis by swine neutrophils . Capsule depolymerization of serogroup A strains with hyaluronidase increased IHA titers, but depolymerization with chondroitinase did not . When serogroup A strains were treated with a combination of chondroitinase and hyaluronidase, IHA test titers were lower than titers of the same strains treated with hyaluronidase alone . Combined enzyme treatment of serogroup D strains resulted in IHA test titers similar to those of chondroitinase treatment alone.

Vet Microbiol, 1995 Dec, 47(3-4), 281 - 6
Phenotypic characterisation of Pasteurella multocida isolates from Australian poultry; Fegan N et al.; A phenotypic characterisation of 110 isolates of bacteria previously identified as Pasteurella multocida was performed . Reference strains of many of the currently recognised species within the genus Pasteurella were included in the study . All the isolates had been obtained from Australian poultry-67 from chickens, 42 from turkeys and one from a duck . Ten different biochemical biovars were recognised amongst the isolates . Four of these biovars, representing 91 isolates, were identified as P . multocida subsp . multocida . One biovar, consisting of one isolate, was identified as P . multocida subsp . septica and another biovar, consisting of five isolates, as P . multocida subsp . gallicida . Two further biovars were tentatively identified as ornithine decarboxylase negative P . multocida subsp . multocida (five isolates) and maltose positive P . multocida subsp . septica (one isolate) . The final two biovars, consisting of five and two isolates each, could not be assigned to any of the currently recognised subspecies of P . multocida.

Vaccine, 1995 Dec, 13(17), 1677 - 84
Protection of ruminants by Pasteurella haemolytica A1 capsular polysaccharide vaccines containing muramyl dipeptide analogs; Brogden KA et al.; The capsular polysaccharide (CP) of Pasteurella haemolytica serotype A1 is a poor immunogen for the prevention of pneumonic pasteurellosis of ruminants . To improve CP immunogenicity, vaccines were prepared with 1.0 mg CP dose-1 with and without the synthetic adjuvant, muramyl dipeptide (MDP; range 0.2-1.0 mg) or a lipophilic derivative, MDP-sn-glyceryl-dipalmitoyl (MDP-GDP; range 0.1-1.0 mg) . The optimum effective concentration of adjuvant was first determined in lambs and calves and then the efficacy of CP +0.5 mg MDP and CP +1.0 mg MDP-GDP was compared with that of two commercial vaccines in calves . After immunization with CP, antibody titers in lambs and calves were typical of that seen with polysaccharide immunogens and characterized by an early IgM response followed by later IgG1 and IgG2 responses . CP + MDP or MDP-GDP vaccines induced significantly higher IgM, IgG1, and IgG2 titers . After transtracheal challenge of immunity with P . haemolytica serotype A1, extensive pulmonary consolidation containing P . haemolytica (10(6)-10(8) c.f.u . g-1) was seen in all lambs and calves vaccinated with CP alone and was not significantly different (P < 0.05) from the consolidation and concentrations of organisms in nonvaccinated challenge controls . In lambs, vaccines containing 1.0 mg CP +0.05 mg MDP or MDP-GDP significantly reduced pulmonary consolidation and concentrations of P . haemolytica in lung lesions . In calves, vaccines containing 0.2 mg MDP, 0.5 mg MDP, or 1.0 mg MDP-GDP also significantly reduced pulmonary consolidation and concentrations of P . haemolytica in lung lesions . Vaccines containing CP +0.5 mg MDP and CP +1.0 mg MDP-GDP induced high titer bactericidal antibodies by 7 days and were more efficacious than two commercial vaccines . Potentiation of CP with MDP or MDP-GDP has great promise in furthering the potential of CP as a vaccine immunogen for the prevention of pneumonic pasteurellosis.

Onderstepoort J Vet Res, 1995 Dec, 62(4), 223 - 6
The distribution of Pasteurella haemolytica serotypes among cattle, sheep, and goats in South Africa and their association with diseases; Odendaal MW et al.; Over an 8-year period (September 1986 to March 1994), a total of 497 organ specimens from sheep and goats and 96 from cattle, were received for their isolation of Pasteurella haemolytica . They were collected in seven geographical areas in South Africa (as it existed before the April 1994 elections) . These areas include the eastern Cape, Transvaal (new name: Gauteng), Nambia, Orange Free State (new name: Free State), Natal (new name: KwaZulu-Natal), western Cape and the northern Cape . This investigation does not represent the statistical incidence of the organism from each region, only the distribution of serotypes isolated from organ specimens submitted from diseased animals in these regions . Pasteurella haemolytica serotype 6 was the most prevalent type isolated from sheep and goats, but was followed closely by types 9 and 2 . From cattle, P . haemolytica serotype 1 comprised 39% of the isolates . In sheep and goats, the majority of serotypes were associated with pneumonia, followed by gangrenous mastitis ("blue udder") and septicaemia . The situation in cattle was similar regarding the incidence of pneumonia followed by septicaemia . Up to 33% of the isolates from cattle and sheep specimens were non-typeable.

Gene, 1995 Dec 1, 166(1), 179 - 80
Cloning and sequence of the groESL heat-shock operon of Pasteurella multocida; Love BC et al.; By using degenerate oligodeoxyribonucleotide primers for conserved regions of groEL, a 0.6-kb fragment of Pasteurella multocida genomic DNA was amplified using PCR . The amplified fragment was then used as a probe to isolate a genomic fragment containing the entire GroESL operon . The isolated genomic fragment was found to contain two open reading frames, the sequences of which were highly homologous to the prokaryotic groES and groEL families of genes.

J Am Acad Dermatol, 1995 Dec, 33(6), 1019 - 29
Dog, cat, and human bites: a review; Griego RD et al.; It is estimated that half of all Americans will be bitten by an animal or another human being during their lifetimes . The vast majority of the estimated 2 million annual mammalian bite wounds are minor, and the victims never seek medical attention . Nonetheless, bite wounds account for approximately 1% of all emergency department visits and more than $30 million in annual health care costs . Infection is the most common bite-associated complication; the relative risk is determined by the species of the inflicting animal, bite location, host factors, and local wound care . Most infections caused by mammalian bites are polymicrobial, with mixed aerobic and anaerobic species . The clinical presentation and appropriate treatment of infected bite wounds vary according to the causative organisms . Human bite wounds have long had a bad reputation for severe infection and frequent complication . However, recent data demonstrate that human bites occurring anywhere other than the hand present no more of a risk for infection than any other type of mammalian bite . The increased incidence of serious infections and complications associated with human bites to the hand warrants their consideration and management in three different categories: occlusional/simple, clenched fist injuries, and occlusional bites to the hand . This article reviews dogs, cat, and human bite wounds, risk factors for complications, evaluation components, bacteriology, antimicrobial susceptibility patterns, and recommended treatments . Epidemiology, clinical presentation, and treatment of infections caused by Pasteurella multocida, Capnocytophaga canimorsus, Eikenella corrodens, and rhabdovirus (rabies only) receive particular emphasis.

Dtsch Med Wochenschr, 1995 Nov 17, 120(46), 1582 - 6
{Interstitial pneumonia and sepsis due to a Pasteurella multocida infection}; Schlichthaar H et al.; HISTORY AND CLINICAL FINDINGS: A 65-year-old diabetic (requiring insulin during the last year) was admitted as an emergency because of a septic temperature rising to 40 degrees C with rigor, tachycardia (up to 120/min) and dyspnoea . On examination there was local reddening and swelling of the skin over the right thenar eminence and along the lower arm . Two days before admission a bad scratch had been inflicted on his right hand by a cat . He had first noticed the reddening and swelling 10 hours after the incident; 1 1/2 days after the scratch and 9-10 hours before hospitalization the first bouts of fever had occurred . EXAMINATIONS: The chest radiogram showed interstitial pneumonia . The clinical findings, the laboratory tests (white cell count 21 750/microliters, platelets 140,000/microliters, C-reactive protein 35 mg/l and positive blood cultures pointed to early septicaemia . The germ was identified as Pasteurella multocida two days after blood had been taken for culturing . HbA1c was 11.38% . TREATMENT AND COURSE: From the time of hospitalization the patient had been treated with ceftriaxon, 2 g daily intravenously, and also with erythromycin because atypical pneumonia had been the suspected diagnosis at first and acute chlamydia infection had at first not been excluded . The patient's general condition quickly improved and the fever started to go down a few hours after onset of treatment . Blood cultures became negative after the first administration of antibiotics . He was discharged in a good state on optimal insulin dosage . CONCLUSION: Pasteurella multocida is present in a high percentage of domestic animals and can be the cause of systemic infections in immunocompromised patients (e . g . poorly controlled diabetes mellitus).

Kansenshogaku Zasshi, 1995 Nov, 69(11), 1302 - 6
{A case of Pasteurella multocida subsp . multocida septicemia due to cat bites in liver cirrhosis patient}; Shimizu T et al.; A 60-year-old male who had been suffering from liver cirrhosis was admitted to our hospital with high grade fever accompanied by right chest pain . Chest X-rays revealed a moderate amount of pleural fluid suggesting pleuritis . Multocida was isolated from the blood culture as well as the pleural fluid . Antibiotic therapy was initiated according to the drug susceptibility of the isolates . Ten days treatment was effective on the cessation of both septicemia and the clinical symptoms . Since the patient had been bitten several times by his own pet cats, their mouth swabs were taken for pathogenic investigations . Serotypes of the cats' isolates coincided with that of the patient's which consequently indicated the route of infection . P . multocida is a Gram negative coccobacillary organism that resides as normal flora in the oral cavity of animals, including dogs and cats . It has been originally known to be a causative agent for hemorrhagic septicemia in domestic animals . However, recently reports of P . multocida infections in man has been increasing due to the enlargement of pet populations . Although outbreaks of septicemia is rare, it occurs most often in immunologically compromised hosts, including patients with liver cirrhosis as in this case . Therefore, it is important to initiate an urgent antibiotic therapy in such cases . Overall, it is of utmost importance to instruct immunosuppressed patients to avoid excessive exposure to animals including pets.

Dtsch Tierarztl Wochenschr, 1995 Nov, 102(11), 427 - 30
{Are nasal swabs for swine appropriate for the diagnosis of bacterial pneumonia agents?}; Schoss P et al.; Nasal swabs and lungs of 150 pigs with pneumonia were tested by culture at post mortem examination . The isolated agents were Pasteurella multocida (P.m.), P . haemolytica, Bordetella bronchiseptica, Actinobacillus pleuropneumoniae, Staphylococcus aureus, Streptococcus spp . and Escherichia coli . P.m . was most frequently found, and this agent only showed a significant correlation between lungs and nasal swabs . In 80.6% of pigs with P.m . in the lung the agent was detected in the nose, too . Drug resistance patterns of P.m . isolates from lungs and noses of the single animals were identical or similar, also in case of different capsular types . The examination of porcine nasal swabs for bacteria capable of causing pneumonia should be limited to P . multocida . Demonstration of agents in lung material is generally more certain.

J Antimicrob Chemother, 1995 Nov, 36(5), 815 - 9
Tetracycline resistance determinants, Tet B and Tet M, detected in Pasteurella haemolytica and Pasteurella multocida from bovine herds; Chaslus-Dancla E et al.; Resistance to antibiotics has recently emerged in Pasteurella haemolytica and Pasteurella multocida isolated from bovine herds . Forty-two clinical strains resistant to antibiotics and isolated through a French national network from different origins were analysed for their resistance to tetracycline . The MICs of tetracycline ranged from 32-256 mg/L . The resistance determinants Tet B and Tet M were detected in two strains, in which they are probably chromosomal.

Vet Pathol, 1995 Nov, 32(6), 674 - 82
Reduced physeal area and chondrocyte proliferation in Pasteurella multocida toxin-treated rats; Ackermann MR et al.; Pasteurella multocida toxin depresses weight gain in rats and pigs . It also affects tissues with rapidly dividing cells . In the present study, we investigated the role of this protein toxin on chondrocyte growth in vivo . Rats were divided into a single- or multiple-dose group and were given, respectively, either a single injection (0.15 or 0.6 micrograms/kg toxin subcutaneously) or multiple injections (0.01-0.2 micrograms/kg subcutaneously) of toxin . Bone (humerus) and other selected tissues were stained for bromodeoxyuridine immunoreactivity (BrDU-IR) in order to gauge cell proliferation . Physeal area was measured in rats from the multiple-dose group . Serum from single- and multiple-dose groups were tested for tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) activity using a bioassay system . Decreased weight gain, feed intake, and feed efficiency were observed in single- and multiple-dose groups of rats . Decreased BrDU-IR indices were present in the resting and proliferative zone chondrocytes of the humeral physis in rats from the multiple-dose group, as was decreased physeal area . Increased serum IL-6 bioactivity was present in rats after 24 hours, and no changes in TNF-alpha bioactivity were seen in any group . No alterations in BrDU-IR were seen in rats fed restricted (80% of control) diets . These studies show that sublethal doses of toxin decrease weight gain and affect growth of long bones through suppression of chondrocyte proliferation . These effects may be mediated by direct binding of the toxin to target cells or IL-6 but are not associated with altered feed intake or TNF-induced cachexia.

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