Mutat Res, 2001 Feb 20, 490(2), 131 - 9 Oxidative mutagenesis of doxorubicin-Fe(III) complex; Kostoryz EL et al.; Doxorubicin has a high affinity for inorganic iron, Fe(III), and has potential to form doxorubicin-Fe(III) complexes in biological systems . Indirect involvement of iron has been substantiated in the oxidative mutagenicity of doxorubicin . In this study, however, direct involvement of Fe(III) was evaluated in mutagenicity studies with the doxorubicin-Fe(III) complex . The Salmonella mutagenicity assay with strain TA102 was used with a pre-incubation step . The highest mutagenicity of doxorubicin-Fe(III) complex was observed at the dose of 2.5nmol/plate of the complex . The S9-mix decreased this highest mutagenicity but increased the number of revertants at a higher dose of 10nmol/plate of the complex . On the other hand, the mutagenicity of the doxorubicin-Fe(III) complex at the doses of 0.25, 0.5, 1 and 2nmol/plate was enhanced about twice by the addition of glutathione plus H(2)O(2) . This enhanced mutagenicity as well as of the complex itself, the complex plus glutathione, and the complex plus H(2)O(2) were reduced by the addition of ADR-529, an Fe(III) chelator, and potassium iodide, a hydroxyl radical scavenger . These results indicate that doxorubicin-Fe(III) complex exert the mutagenicity through oxidative DNA damage and that Fe(III) is a required element in the mutagenesis of doxorubicin. Rev Inst Med Trop Sao Paulo, 2001 Mar-Apr, 43(2), 67 - 74 Pyogenic abscesses and parasitic diseases; Lambertucci JR et al.; Parasitic diseases which during their course in the host switch the immune system from a T helper 1 to a T helper 2 response may be detrimental to the host, contributing to granuloma formation, eosinophilia, hyper-IgE, and increased susceptibility to bacterial and fungal infections . Patients and animals with acute schistosomiasis and hyper-IgE in their serum develop pyogenic liver abscess in the presence of bacteremia caused by Staphylococcus aureus . The Salmonella-S . mansoni association has also been well documented . The association of tropical pyomyositis (pyogenic muscle abscess) and pyogenic liver abscess with Toxocara infection has recently been described in the same context . In tropical countries that may be an interesting explanation for the great morbidity of bacterial diseases . If the association of parasitic infections and pyogenic abscesses and/or fungal diseases are confirmed, there will be a strong case in favor of universal treatment for parasitic diseases to prevent or decrease the morbidity of superinfection with bacteria and fungi. J Nutr, 2001 May, 131(5), 1452 - 8 Elevated iron status increases bacterial invasion and survival and alters cytokine/chemokine mRNA expression in Caco-2 human intestinal cells; Foster SL et al.; Iron status affects both microbial growth and immune function . Mammalian iron homeostasis is maintained primarily by regulating the absorption of the micronutrient in the proximal small intestine . The iron concentration of the enterocyte can fluctuate widely in response to both dietary and whole body iron status, as well as in response to infections . The possibility that an enterocyte with an elevated iron concentration is more susceptible to invasion by enteric pathogens is not known . Therefore, we examined the impact of enterocyte iron status on the invasion and survival of an enteric pathogen, as well as on the levels of several cytokine and chemokine mRNAs by the host cell . The enterocyte-like Caco-2 human intestinal cell line and Salmonella enteritidis served as the models to examine the effect of iron on the host-parasite interaction . Iron status of Caco-2 cells was altered by incubation in serum-free medium supplemented with varying levels of iron . Elevated iron status of Caco-2 cells increased the efficiency of the invasion and the number of bacteria surviving in the intracellular environment . Caco-2 cells constitutively expressed transforming growth factor-beta1, interleukin-8, monocyte chemotactic protein-1, tumor necrosis factor-alpha and interleukin-1beta, and infection with S . enteritidis increased the relative quantities of all cytokine/chemokine mRNAs except interleukin-1beta . Elevated iron status of Caco-2 cells decreased the levels of cytokine/chemokine mRNAs by 25-45% in uninfected cells . In contrast, bacterial infection was associated with a 21-95% increase in cytokine/chemokine mRNAs levels in Caco-2 cells with higher iron concentration compared with infected cells with lower iron concentration . These data support the hypothesis that elevated enterocyte iron status increases susceptibility to infection and exacerbates the mucosal inflammatory response initiated by microbial invasion by increasing cytokine/chemokine expression. J Nutr, 2001 May, 131(5), 1433 - 7 Alanyl-glutamine dipeptide does not affect hemodynamics despite a greater increase in myocardial heat shock protein 72 immunoreactivity in endotoxemic sheep; Scharte M et al.; The possible beneficial effect of supplemental glutamine (Gln) in critically ill patients has been suggested to be mediated by the induction of the cytoprotective heat shock proteins (HSP)32 and HSP72 . There is evidence that HSP72 and HSP32 have opposite effects on the hemodynamic situation during endotoxemia . Therefore, the effect of Gln supplementation on the cardiovascular system is not clear . We investigated the effect of alanyl-Gln (Ala-Gln) dipeptide on cardiovascular function in healthy and endotoxemic sheep . Ten sheep catheterized for chronic studies received Ala-Gln 700 mg/(kg x d) {equal to 470 mg/(kg x d)Gln} on 4 consecutive days, and 10 sheep received NaCl (9 g/L) as the control solution . On d 4, four sheep of each group were killed and myocardial samples were taken for immunohistochemistry . The remaining sheep received a continuous infusion of endotoxin {Salmonella typhosa, 10 ng/(kg x min)} . Hemodynamic parameters were measured before application of Ala-Gln or the control solution, and during endotoxemia . Myocardial HSP72 immunoreactivity was determined by immunohistochemistry . After 24 h of endotoxemia, the sheep exhibited a hyperdynamic circulation . No difference was found in the hemodynamic parameters between treatment and control group . Ala-Gln treated sheep had a greater increase in myocardial HSP72 immunoreactivity compared with controls after (P < 0.05) but not before endotoxemia . In summary, Ala-Gln increased HSP72 immunoreactivity after endotoxemia, but did not alter hemodynamic parameters . Thus, Ala-Gln supplementation does not seem to aggravate the hyperdynamic circulation in endotoxemic shock. Infection, 2001 Mar-Apr, 29(2), 103 - 6 Salmonella encephalopathy with seizure and frontal intermittent rhythmic delta activity; Uysal H et al.; A 54-year-old woman was admitted to our clinic with frequent convulsions . Subsequently she developed a toxic look, rigidity, confusion and severe encephalopathy . Salmonella typhii was isolated from the blood cultures and she was diagnosed with Salmonella encephalopathy . The prominent electrophysiological finding was the frontal intermittent rhythmic delta activity (FIRDA) in electroencephalograph (EEG) . After treatment EEG revealed normal activity . The presence of FIRDA is not a specific finding but this kind of EEG change has not been reported before . Diffuse encephalopathy due to endotoxins might be the reason . We propose that S . typhii encephalopathy was the cause of FIRDA which is a sign of diffuse encephalopathy. Food Addit Contam, 2001 Apr, 18(4), 329 - 41 Genotoxicity testing of extracts from aflatoxin-contaminated peanut meal, following chemical decontamination; Hoogenboom LA et al.; One of the most important concerns in the decontamination of aflatoxin-containing feed commodities is the safety of the products for food-producing animals and for human consumption of products derived from these animals . A new method, based on the use of florisil and C18 solid phase extraction columns, was developed for the preparation of extracts from decontaminated peanut meal, which allowed testing with in vitro genotoxicity assays without interference of the residual aflatoxin B1 . Recovery of degradation products in the extracts was evaluated by the use of radiolabelled {14C}-aflatoxin B1 (AFB1) added to naturally-contaminated peanut meal (3.5 mg AFB1/kg) . The meal was treated by a small-scale version of an industrial decontamination process based on ammoniation . Following decontamination, more than 90% of the label could not be extracted from the meal . AFB1 accounted for about 10% of the radiolabel present in the extractable fraction, indicating a total AFB1 reduction of more than 99% . Decontamination of the meal by a number of other small- and industrial-scale ammonia-based processes resulted in similar efficiencies . Application of the extraction procedure resulted in AFB1-rich and AFB1-poor fractions, the latter containing half of the extractable decontamination products but less than 1% of the residual AFB1 . Testing in the Salmonella/microsome mutagenicity assay (TA 100, with S9-mix) of the original crude extracts and AFB1-rich fractions prepared from non-treated and decontaminated meal, showed the positive results expected from the AFB1 contents as determined by HPLC analysis . Analysis and testing of the AFB1-poor fractions showed that the various decontamination processes not only resulted in a successful degradation of AFB1 but also did not produce other potent mutagenic compounds . Slight positive results obtained with these extracts were similar for the untreated and treated meals and may be due to unknown compounds originally present in the meal . Results obtained with an unscheduled DNA synthesis (UDS) and Comet assay with rat hepatocytes supported this conclusion . Positive results obtained with the micronucleus assay, using immortalized mouse hepatocytes (GKB), did not clearly reflect the mycotoxin levels and require further examination . It is concluded that the newly developed extraction procedure yields highly reproducible fractions and hence is very suitable for examining the possible formation of less potent degradation products of aflatoxins in short-term genotoxicity tests. J Med Microbiol, 2001 May, 50(5), 415 - 20 An attempt to identify the evolutionary origin of a novel serotype of Salmonella enterica isolated from harbour porpoises; Old DC et al.; The isolation since 1991 of a new serotype of Salmonella enterica (antigenic formula 4,12:a:-) from harbour porpoises (Phocoena phocoena) at post-mortem examination raised the question of its evolutionary origin . Representative strains of S . enterica serotype 4,12:a:- and strains of eight other serotypes of serogroup 04 with phase-1 flagellar antigen H 'a' were examined by EcoRI ribotyping, IS200 fingerprinting and PCR-based profiling . Statistical analysis of results of multiple typing showed that strains of Salmonella serotype 4,12:a:- were genetically distant from those of antigenically similar salmonella serotypes, none of which seemed likely to be the progenitor of the 'porpoise' serotype. Vestn Ross Akad Med Nauk, 2001, (2), 21 - 5 {Immunosuppressive effects of pathogenic gram-negative bacteria}; Vorob'ev AA et al.; The review deals with the Immunosuppressive effects of virulent gram-negative bacteria (Salmonella, Shigela, Pseudomonas aeruginosa), with the importance of these effects for the bacteria to survive in the infected body . The above bacteria affect the immunity system in a different way, yet have common features . They are characterized by the occurrence of endotoxin shock, by the suppression of the phagocytic system and cell-mediated immunity . A significant role in suppressing a cellular immune response is played by the lipopolysaccharide of virulent bacteria that greatly differs from that of nonvirulent strains . The immunosuppressive activity of the bacteria and their lipopolysaccharide is closely related to their virulent properties. Vet Microbiol, 2001 Jun 6, 80(3), 267 - 74 Monitoring of transmission of Salmonella enterica serovars in pigs using bacteriological and serological detection methods; van Winsen RL et al.; The standard method to detect Salmonella positive pigs is bacteriological examination of the faeces, but in recent years the use of Salmonella-ELISA's have become available to screen pigs for serological evidence of infection . This study was conducted to monitor the transmission of five different Salmonella enterica serovars (S . Typhimurium, S . Brandenburg, S . Panama, S . Livingstone, and S . Goldcoast) in fattening pigs and to test the feasibility of Salmonella-ELISA, using seeder pigs as a mode of transmission . Serovar dependence in transmission was observed . The Salmonella-ELISA proved to be useful to detect S . Typhimurium and S . Brandenburg in herds but was of limited value to demonstrate S . Livingstone, S . Goldcoast, and S . Panama. Vet Microbiol, 2001 Jun 6, 80(3), 235 - 45 The SEF14 fimbrial antigen of Salmonella enterica serovar Enteritidis is encoded within a pathogenicity islet; Collighan RJ et al.; The DNA sequence of the chromosomal gene cluster encoding the SEF14 fimbriae of Salmonella enterica serovar Enteritidis was determined . Five contiguous open reading frames, sefABCDE, were identified . The sefE gene shared significant homology with araC-like positive regulators . Serovar-associated virulence plasmid (SAP) genes orf7,8,9 and pefI were identified immediately adjacent to the sef operon . The pefI gene encoded a putative regulator of the Plasmid-encoded fimbrial antigen (PEF) expression . The entire sef--pef region, flanked by two IS-like elements, was inserted adjacent to leuX that encoded a transfer RNA molecule . The organisation of this region was suggestive of a classic pathogenicity islet . Southern hybridisation confirmed two copies of the SAP derived orf7,8,9 and pefI region in S . Enteritidis, one in the chromosome and one on the SAP . Of other group D Salmonella, only S . Blegdam and S . Moscow harboured both chromosomal and plasmid copies of pefI--orf9 region although polymorphism was evident. Mutat Res, 2001 May 9, 476(1-2), 133 - 7 SAR modeling of genotoxic phenomena: the effect of supplementation with physiological chemicals; Rosenkranz HS et al.; Structure-activity relationship (SAR) modeling of toxicological phenomena is optimal when the ratio of toxicants to non-toxicants included in the model is unity . Frequently, however, the experimental data available are enriched with toxicants, this appears to be especially true for genotoxicity data sets . It is demonstrated herein, using a Salmonella mutagenicity data set, that when there is a paucity of non-toxicants, the learning set may be augmented with physiological chemicals on the assumption that they are non-genotoxic. FEMS Immunol Med Microbiol, 2001 Apr, 30(3), 203 - 8 Flagellin expressed by live Salmonella vaccine strains induces distinct antibody responses following delivery via systemic or mucosal immunization routes; Sbrogio-Almeida ME et al.; Salmonella flagellin, expressed as flagella in live attenuated vaccine strains, elicits distinct systemic (IgG) and secreted (IgA) antibody responses in mice following delivery via mucosal (nasal/oral) or parenteral (intraperitoneal (i.p.)) immunization routes . Reduced flagellin-specific antibodies were detected either systemically or locally following delivery of flagellated derivatives of aroA Salmonella enterica serovar Dublin SL1438 via the nasal route, the most effective mucosal site for activation of immune responses in mice . In contrast, flagellin represents the most potent Salmonella antigen for the generation of specific serum antibody (IgG) responses following i.p . inoculations . The distinct immunogenic properties of Salmonella flagellin could not be ascribed to deficient colonization, reduced invasive ability or loss of the flagellin expression by the flagellated vaccine strains. Int Microbiol, 2000 Dec, 3(4), 225 - 9 Detection of Salmonella in food samples by the combination of immunomagnetic separation and PCR assay; Jenikova G et al.; A combination of immunomagnetic separation and polymerase chain reaction (IMS-PCR) was used to detect Salmonella in food samples . Pre-enrichment of samples was combined with filtration through a membrane for the removal of food debris . The IMS-PCR assay combines selective extraction of bacteria by specific antibodies with primer specific PCR amplification that enables to detect Salmonella in non-fatty food samples in 24 h . In comparison with conventional cultural methods, the IMS-PCR is a rapid and specific method . Combined with filtration bags, it partially reduces the negative effects of the food matrix and allows the quick detection of Salmonella cells . The shortened protocols for Salmonella spp . detection described here can improve considerably current methodologies. Neurosurgery, 2001 May, 48(5), 1152 - 6 Mycotic aneurysm of the carotid bifurcation in the neck: case report and review of the literature; Nader R et al.; OBJECTIVE AND IMPORTANCE: Mycotic aneurysms of the extracranial carotid artery are rare and difficult to diagnose . A search of the world literature published since 1966 reveals at least six cases of mycotic carotid aneurysms due to a Salmonella septicemia . We present an exceptional case of mycotic pseudoaneurysm of the bifurcation of the carotid artery due to Salmonella septicemia and discuss the pathogenesis as well as various aspects of the diagnosis and surgical management . CLINICAL PRESENTATION: A 68-year-old man presented in Poland with Salmonella sepsis; 1 month later, he was admitted to the emergency department of the Sir Mortimer B . Davis-Jewish General Hospital in Montreal with a bulky and pulsatile right cervical mass . An angiogram and a computed tomographic scan revealed a voluminous and partially thrombosed aneurysm the size of a tangerine originating from the posterior aspect of the carotid junction . INTERVENTION: Balloon trapping was attempted at the Montreal Neurological Hospital . Subsequently, the patient developed a significant neurological deficit, which was quickly reversed by the administration of hypertensive, hypervolemic, and hemodilution therapy . Thereafter, the pseudoaneurysm was resected surgically, and the internal and external carotid arteries were sacrificed . Pathological examination of the excised specimen of the carotid junction revealed a pseudoaneurysm . Bacterial culture of the lesion showed growth of Salmonella . CONCLUSION: The postoperative course was satisfactory except for laryngeal paralysis due to involvement of the vagus nerve . Four months later, a computed tomographic scan showed only small lacunae in both centra semiovale. J Biomater Sci Polym Ed, 2001, 12(1), 89 - 105 Quantum mechanical quantitative structure activity relationships to avoid mutagenicity in dental monomers; Yourtee D et al.; The objective of this study was to identify through quantum mechanical quantitative structure activity relationships (Q-QSARs) chemical structures in dental monomers that influence their mutagenicity . AMPAC, a semiempirical computer program that provides quantum mechanical information for chemical structures, was applied to three series of reference chemicals: a set of methacrylates, a set of aromatic and a set of aliphatic epoxy compounds . QSAR models were developed using this chemical information together with mutagenicity data (Salmonella TA 100, Ames Test) . CODESSA, a QSAR program that calculates quantum chemical descriptors from information generated by AMPAC and statistically matches these descriptors with observed biological properties was used . QSARs were developed which had r2 values exceeding 0.90 for each study series . These QSARs were used to accurately predict the mutagenicity of BISGMA . a monomer commonly used in dentistry, and two epoxy monomers with developing use in dentistry, GY-281 and UVR-6105 . The Q-QSAR quantum mechanical descriptors correctly predicted the level of mutagenicity for all three compounds . The descriptors in the correlation equation pointed to components of structure that may contribute to mutagenesis . The QSARs also provided 'dose windows' for testing mutagenicity, circumventing the need for extensive dose exploration in the laboratory . The Q-QSAR method promises an approach for biomaterials scientists to predict and avoid mutagenicity from the chemicals used in new biomaterial designs. An Esp Pediatr, 2001 May, 54(5), 510 - 2 {Reactive arthritis shortly after Streptococcus b-hemolyticus type A and Salmonella type B infection}; Gomez Carrasco J et al.; We report the case of a girl aged 2 years and 8 months with monoarticular arthritis of the knee . Onset and outcome were slow . The child had suffered uncomplicated pharyngitis and a diarrheal process 1 and 2 weeks respectively prior to developing the disease . Additional data suggested the presence of reactive arthritis after Streptococcus infection . Salmonella was also detected in the feces . Unlike rheumatic fever, post-streptococcus reactive arthritis does not follow Jones' criteria and the clinical course is slow . Because gastrointestinal infection with both Streptococcus and Salmonella occurred simultaneously, the interaction between both agents, each of which alone can cause reactive arthritis, might have produced a synergic action in our patient. South Med J, 2001 Apr, 94(4), 435 - 7 Soft tissue and cartilage infection by Salmonella oranienburg in a healthy girl; Porcalla AR et al.; Focal extraintestinal infections from nontyphoid salmonellae have increased in incidence during the past decade . Typically, they are manifested as either osteomyelitis or meningitis as a complication of either bacteremia or enteric fever . Isolated salmonellal soft tissue infections, however, are rare and occur mostly in adults with chronic underlying conditions such as human immunodeficiency virus (HIV) infection, diabetes mellitus, and cell-mediated immunity defects . We report a case of an otherwise healthy adolescent who was exposed to a guinea pig with a skin mass . She subsequently had an isolated soft tissue infection with cartilaginous involvement of the anterior chest wall due to Salmonella enterica serogroup C1 (bioserotype oranienburg). South Med J, 2001 Apr, 94(4), 427 - 8 Endocarditis due to Salmonella; Flannery MT et al.; We present a case of endocarditis caused by Salmonella in a patient with newly diagnosed diabetes and preexisting rheumatic heart disease . Despite sterilization of the blood with a fluoroquinolone and a third-generation cephalosporin, the patient required surgical intervention. Avian Dis, 2001 Jan-Mar, 45(1), 195 - 200 Comparison of Salmonella isolation rates in different types of egg-layer hen houses in Chiba, Japan; Matsumoto A et al.; This study investigated the differences in Salmonella isolation rates in environmental samples taken from several types of hen houses in Chiba, Japan . In addition, for the detailed epidemiologic survey, environmental samples, hens, and rodents were collected from Salmonella-contaminated windowless houses on three farms . As a result, Salmonella was isolated from four (80%) of five farms with windowless hen houses; Salmonella enteritidis was isolated from a single windowless house . In contrast, only one serotype of Salmonella was isolated from 1 (6.7%) of 15 farms with open hen houses . In the S . enteritidis-contaminated windowless hen house, the isolation rates of S . enteritidis as compared with the other serotypes were 90.9% of environments, 94.1% of hens, and 86.4% of roof rats (Rattus rattus) that resided in the environments . In reference to the phage type (PT) of these isolates, PT1 was detected in environments and roof rats, and PT9 was detected in both these samples and in hens . Thus, the Salmonella isolation rate in hen houses seems to be associated with whether the premises are windowless or open . Moreover, roof rats appear to be the most important vectors in the spread of S . enteritidis in the windowless hen house because the S . enteritidis PTs coincide with each other. EMBO J, 2001 May 1, 20(9), 2131 - 9 Cooperation between actin-binding proteins of invasive Salmonella: SipA potentiates SipC nucleation and bundling of actin; McGhie EJ et al.; Pathogen-induced remodelling of the host cell actin cytoskeleton drives internalization of invasive Salmonella by non-phagocytic intestinal epithelial cells . Two Salmonella actin-binding proteins are involved in internalization: SipC is essential for the process, while SipA enhances its efficiency . Using purified SipC and SipA proteins in in vitro assays of actin dynamics and F-actin bundling, we demonstrate that SipA stimulates substantially SipC-mediated nucleation of actin polymerization . SipA additionally enhances SipC-mediated F-actin bundling, and SipC-SipA collaboration generates stable networks of F-actin bundles . The data show that bacterial SipC and SipA cooperate to direct efficient modulation of actin dynamics, independently of host cell proteins . The ability of SipA to enhance SipC-induced reorganization of the actin cytoskeleton in vivo was confirmed using semi-permeabilized cultured mammalian cells. Environ Sci Technol, 2001 Apr 15, 35(8), 1630 - 6 Evaluation of methods for predicting the toxicity of polycyclic aromatic hydrocarbon mixtures; Reeves WR et al.; Risk assessments of polycyclic aromatic hydrocarbon mixtures are hindered by a lack of reliable information on the potency of both mixtures and their individual components . This paper examines methods for approximating the toxicity of polycyclic aromatic hydrocarbon (PAH) mixtures . PAHs were isolated from a coal tar and then separated by ring number using HPLC . Five fractions (A-E) were generated, each possessing a unique composition and expected potency . The toxicity of each fraction was measured in the Salmonella/mutagenicity assay and the Chick Embryo Screening Test (CHEST) . Their abilities to induce ethoxyresorufin-O-deethylase and to inhibit gap junction intercellular communication in rat liver Clone 9 cells were also measured . In the Salmonella/mutagenicity assay, fractions were predicted to have potencies in the order C > D > E > B > A . Toxic equivalency factors (TEFs) for fractions A-E were in the order E > or = D > C > B > A . TEF values were 20,652, 20,929, 441, 306, and 74.1 micrograms of BaP equiv/g, respectively . A lack of agreement between assay-predicted potencies and chemical analysis-predicted potencies was observed with other assays and other methods of calculation . The results demonstrate the limitations of using a single method to predict the toxicity of a complex PAH mixture. J Mol Biol, 2001 Apr 27, 308(2), 221 - 9 Flagellin polymerisation control by a cytosolic export chaperone; Auvray F et al.; Assembly of the long helical filament of the bacterial flagellum requires polymerisation of ca 20,000 flagellin (FliC) monomeric subunits into the growing structure extending from the cell surface . Here, we show that export of Salmonella flagellin is facilitated specifically by a cytosolic protein, FliS, and that FliS binds to the FliC C-terminal helical domain, which contributes to stabilisation of flagellin subunit interactions during polymerisation . Stable complexes of FliS with flagellin were assembled efficiently in vitro, apparently by FliS homodimers binding to FliC monomers . The data suggest that FliS acts as a substrate-specific chaperone, preventing premature interaction of newly synthesised flagellin subunits in the cytosol . Compatible with this view, FliS was able to prevent in vitro polymerisation of FliC into filaments . J Clin Microbiol, 2001 May, 39(5), 1871 - 6 Detection of salmonellae in chicken feces by a combination of tetrathionate broth enrichment, capillary PCR, and capillary gel electrophoresis; Carli KT et al.; This report describes a rapid detection procedure for salmonellae from chicken feces by the combination of tetrathionate primary enrichment (preenrichment {PE})-bacterial lysis-capillary PCR and capillary gel electrophoresis . Pure Salmonella enterica serovar Enteritidis 64K was reisolated and detected by capillary PCR after buffered peptone water and nutrient broth, tetrathionate broth base Hajna (TTBH), and tetrathionate broth (TTB) preenrichments . When the same culture was mixed with intestinal homogenate, bacteriological reisolation and capillary PCR detection was achieved only by TTBH and TTB preenrichments . Capillary gel electrophoresis revealed that a Salmonella genus-specific 281-bp PCR product was detected when Salmonella strains but not non-Salmonella strains were tested . The detection limit of capillary PCR with whole-cell DNA extracted from pure Salmonella enterica serovars Enteritidis 64K, Typhimurium LT2-CIP60-62, and Gallinarum 64K was 3, 3, and 9 CFU ml(-1), respectively . The detection limit of capillary PCR from whole-cell DNA extracted from intestinal homogenate artificially contaminated with the same three strains was 3, 3, and 7 CFU ml(-1), respectively . We compared the results of the capillary PCR and bacteriological examination from the natural samples . Thirty-five of 53 naturally contaminated samples produced a specific PCR product . In 9 of the 35 PCR-positive samples, Salmonella could not be detected bacteriologically either by PE or a primary and delayed secondary enrichment (DSE) combination . In the 18 PCR-negative samples, 4 samples were found to harbor Salmonella by both PE and DSE and 14 samples were positive after DSE . Fifty-three additional intestinal homogenate samples, which were negative by their PE and DSE in bacteriological examination, were found to be also negative by their PCRs . The total time required to detect Salmonella with the capillary PCR method we used was approximately 20 h . If samples are from clinically diseased birds, the total time for PCR and detection is reduced to 2 h since the 18-h PE is not required . These results indicate that TTB enrichment, bacterial lysis, and genus-specific capillary PCR combined with capillary gel electrophoresis constitute a sensitive and selective procedure which has the potential to rapidly identify Salmonella-infected flocks. J Bacteriol, 2001 May, 183(10), 3089 - 97 Aspartic peptide hydrolases in Salmonella enterica serovar typhimurium; Larsen RA et al.; Two well-characterized enzymes in Salmonella enterica serovar Typhimurium and Escherichia coli are able to hydrolyze N-terminal aspartyl (Asp) dipeptides: peptidase B, a broad-specificity aminopeptidase, and peptidase E, an Asp-specific dipeptidase . A serovar Typhimurium strain lacking both of these enzymes, however, can still utilize most N-terminal Asp dipeptides as sources of amino acids, and extracts of such a strain contain additional enzymatic activities able to hydrolyze Asp dipeptides . Here we report two such activities from extracts of pepB pepE mutant strains of serovar Typhimurium identified by their ability to hydrolyze Asp-Leu . Although each of these activities hydrolyzes Asp-Leu at a measurable rate, the preferred substrates for both are N-terminal isoAsp peptides . One of the activities is a previously characterized isoAsp dipeptidase from E . coli, the product of the iadA gene . The other is the product of the serovar Typhimurium homolog of E . coli ybiK, a gene of previously unknown function . This gene product is a member of the N-terminal nucleophile structural family of amidohydrolases . Like most other members of this family, the mature enzyme is generated from a precursor protein by proteolytic cleavage and the active enzyme is a heterotetramer . Based on its ability to hydrolyze an N-terminal isoAsp tripeptide as well as isoAsp dipeptides, the enzyme appears to be an isoAsp aminopeptidase, and we propose that the gene encoding it be designated iaaA (isoAsp aminopeptidase) . A strain lacking both IadA and IaaA in addition to peptidase B and peptidase E has been constructed . This strain utilizes Asp-Leu as a leucine source, and extracts of this strain contain at least one additional, as-yet-uncharacterized, peptidase able to cleave Asp dipeptides. J AOAC Int, 2001 Mar-Apr, 84(2), 416 - 29 TECRA Unique test for rapid detection of Salmonella in food: collaborative study; Hughes D et al.; The TECRA Unique Salmonella test uses the principle of immunoenrichment to allow rapid detection of Salmonellae in food . A collaborative study was conducted to compare the TECRA Salmonella Unique test with the reference culture method given in the U.S . Food and Drug Administration's Bacteriological Analytical Manual . Three food types (milk powder, pepper, and soy flour) were analyzed in Australia and 2 food types (milk chocolate and dried egg) were analyzed in the United States . Forty-one collaborators participated in the study . For each of the 5 foods at each of the 3 levels, a comparison showed no significant differences (p > or = 0.05) in the proportion of positive test samples for Unique and that for the reference method using the Chi-square test for independence with continuity correction. Int J Food Microbiol, 2001 Apr 11, 65(1-2), 55 - 62 PulseNet standardized protocol for subtyping Listeria monocytogenes by macrorestriction and pulsed-field gel electrophoresis; Graves LM et al.; PulseNet is a national network of pubic health and food regulatory laboratories established in the US to detect clusters of foodborne disease and respond quickly to foodborne outbreak investigations . PulseNet laboratories currently subtype Escherichia coli O157:H7, non-typhoidal Salmonella, and Shigella isolates by a highly standardized 1-day pulsed-field gel electrophoresis (PFGE), and exchange normalized DNA "fingerprint" patterns via the Internet . We describe a standardized molecular subtyping protocol for subtyping Listeria monocytogenes that was recently added to PulseNet . The subtyping can be completed within 30 h from the time a pure culture of the bacteria is obtained. N Engl J Med, 2001 Apr 26, 344(17), 1263 - 9 The efficacy of a Salmonella typhi Vi conjugate vaccine in two-to-five-year-old children; Lin FY et al.; BACKGROUND: Typhoid fever is common in developing countries . The licensed typhoid vaccines confer only about 70 percent immunity, do not protect young children, and are not used for routine vaccination . A newly devised conjugate of the capsular polysaccharide of Salmonella typhi, Vi, bound to nontoxic recombinant Pseudomonas aeruginosa exotoxin A (rEPA), has enhanced immunogenicity in adults and in children 5 to 14 years old and has elicited a booster response in children 2 to 4 years old . METHODS: In a double-blind, randomized trial, we evaluated the safety, immunogenicity, and efficacy of the Vi-rEPA vaccine in children two to five years old in 16 communes in Dong Thap Province, Vietnam . Each of the 11,091 children received two injections six weeks apart of either Vi-rEPA or a saline placebo . Cases of typhoid, diagnosed by the isolation of S . typhi from blood cultures after 3 or more days of fever (a temperature of 37.5 degrees C or higher), were identified by active surveillance over a period of 27 months . We estimated efficacy by comparing the attack rate of typhoid in the vaccine group with that in the placebo group . RESULTS: S . typhi was isolated from 4 of the 5525 children who were fully vaccinated with Vi-rEPA and from 47 of the 5566 children who received both injections of placebo (efficacy, 91.5 percent; 95 percent confidence interval, 77.1 to 96.6; P<0.001) . Among the 771 children who received only one injection, there was 1 case of typhoid in the vaccine group and 8 cases in the placebo group . Cases were distributed evenly among all age groups and throughout the study period . No serious adverse reactions were observed . In all 36 children studied four weeks after the second injection of the vaccine, levels of serum IgG Vi antibodies had increased by a factor of 10 or more . CONCLUSIONS: The Vi-rEPA conjugate typhoid vaccine is safe and immunogenic and has more than 90 percent efficacy in children two to five years old . The antibody responses and the efficacy suggest that this vaccine should be at least as protective in persons who are more than five years old. Proc Natl Acad Sci U S A, 2001 May 8, 98(10), 5850 - 5 Epub 2001 Apr 24. Host microarray analysis reveals a role for the Salmonella response regulator phoP in human macrophage cell death; Detweiler CS et al.; Bacterial pathogens manipulate host cells to promote pathogen survival and dissemination . We used a 22,571 human cDNA microarray to identify host pathways that are affected by the Salmonella enterica subspecies typhimurium phoP gene, a transcription factor required for virulence, by comparing the expression profiles of human monocytic tissue culture cells infected with either the wild-type bacteria or a phoPTn10 mutant strain . Both wild-type and phoPTn10 bacteria induced a common set of genes, many of which are proinflammatory . Differentially expressed genes included those that affect host cell death, suggesting that the phoP regulatory system controls bacterial genes that alter macrophage survival . Subsequent experiments showed that the phoPTn10 mutant strain is defective for killing both cultured and primary human macrophages but is able to replicate intracellularly . These experiments indicate that phoP plays a role in Salmonella-induced human macrophage cell death. Mutagenesis, 2001 May, 16(3), 183 - 7 Micronucleus induction and chromosomal aberration of 1- and 3-nitroazabenzo{a}pyrene and their N-oxides; Sera N et al.; Nitro-azabenzo{a}pyrenes, 1- or 3-nitro-azabenzo{a}pyrene and their N-oxides are nitrated derivatives of azabenzo{a} pyrene (ABP) containing nitrogen in the 6-position of benzo{a}pyrene (B{a}P) . The nitro-ABP-N-oxides (ABPOs) were formed by reaction of ABP with excess HNO(3) . These derivatives were noteworthy as potent mutagens for Salmonella strains, and were present in fine particles of diesel particulates . In this study, micronucleus induction in mice and chromosomal aberrations due to means of Chinese hamster lung fibroblast (CHL) cells were investigated to determine genotoxicity in order to define the relationship with the mutagenic potency of these derivatives . The induction of micronucleus polychromatic erythrocytes (MNPCEs) was dependent on the dose response of 10-40 mg for 3-N-6-ABP, and of 10-40 mg for 1-N-6-ABP, and in addition, 1- and 3-N-6-ABPOs markedly induced MNPCEs in a dose range of 10-400 mg and from 1 to 80 mg, respectively, when the compound was intraperitoneally administrated in two mice at each dose . The results show that of the four compounds, 3-N-6-ABPO demonstrated a marked increase in MNPCES: On the other hand, chromosomal aberrations of the four compounds were investigated by the duplicate tests using CHLS: The results after a 48 h treatment induced aberrations of the chromatid type, chromatid breaks and exchanges for 1- and 3-N-6-ABP, and mainly chromatid exchanges for 1- and 3-N-6-ABPO . The frequency of chromosomal aberrations associated with nitro substitution on the ABPO structure . Chromosomal aberrations of nitro derivatives of ABPO substituted at the 3-position on the structure were more potent than those at the 1-postion . N-oxide derivatives have been found to be reduced to anion radicals much more easily than azaB{a}P and its nitro derivatives . This suggests that the electrochemical reduction of the chemicals plays an important role in the metabolic activation of nitrated B{a}P derivatives. Microbiology, 2001 May, 147(Pt 5), 1087 - 94 Endotoxic properties of lipid A from Comamonas testosteroni; Tanamoto K et al.; The lipid A from Comamonas testosteroni has been isolated and its complete chemical structure determined {Iida, T., Haishima, Y., Tanaka, A., Nishijima, K., Saito, S . & Tanamoto, K . (1996) . Eur J Biochem 237, 468-475} . In this work, the relationship between its chemical structure and biological activity was studied . The lipid A was highly homogeneous chemically and was characterized by the relatively short chain length (C(10)) of the 3-hydroxy fatty acid components directly bound to the glucosamine disaccharide backbone by either amide or ester linkages . The lipid A exhibited endotoxic activity in all of the assay systems tested (mitogenicity in mouse spleen cells; induction of tumour necrosis factor alpha release from both mouse peritoneal macrophages and mouse macrophage-like cell line J774-1, as well as from the human monocytic cell line THP-1; induction of nitric oxide release from J774-1 cells; Limulus gelation activity and lethal toxicity in galactosamine-sensitized mice) to the same extent as did 'Salmonella minnesota' lipid A or Escherichia coli LPS used as controls . The strong endotoxic activity of the C . testosteroni lipid A indicates that the composition of 3-hydroxydecanoic acid is not responsible for the low endotoxicity of the lipid A observed in members of the genus Rhodopseudomonas, as has previously been suggested . Furthermore, both the lack of a second acylation of the 3-hydroxy fatty acid attached at the 3' position, and the substitution of the hydroxyl group of the 3-hydroxy fatty acid attached at position 2, do not affect the manifestation of endotoxic activity or species specificity. Biochemistry, 2001 May 1, 40(17), 5144 - 50 Enthalpic barriers to the hydrophobic binding of oligosaccharides to phage P22 tailspike protein; Baxa U et al.; The structural thermodynamics of the recognition of complex carbohydrates by proteins are not well understood . The recognition of O-antigen polysaccharide by phage P22 tailspike protein is a highly suitable model for advancing knowledge in this field . The binding to octa- and dodecasaccharides derived from Salmonella enteritidis O-antigen was studied by isothermal titration calorimetry and stopped-flow spectrofluorimetry . At room temperature, the binding reaction is enthalpically driven with an unfavorable change in entropy . A large change of -1.8 +/- 0.2 kJ mol(-1) K(-1) in heat capacity suggests that the hydrophobic effect and water reorganization contribute substantially to complex formation . As expected from the large heat-capacity change, we found enthalpy-entropy compensation . The calorimetrically measured binding enthalpies were identical within error to van't Hoff enthalpies determined from fluorescence titrations . Binding kinetics were determined at temperatures ranging from 10 to 30 degrees C . The second-order association rate constant varied from 1 x 10(5) M(-1) s(-1) for dodecasaccharide at 10 degrees C to 7 x 10(5) M(-1) s(-1) for octasaccharide at 30 degrees C . The first-order dissociation rate constants ranged from 0.2 to 3.8 s(-1) . The Arrhenius activation energies were close to 50 and 100 kJ mol(-1) for the association and dissociation reactions, respectively, indicating mainly enthalpic barriers . Despite the fact that this system is quite complex due to the flexibility of the saccharide, both the thermodynamic and kinetic data are compatible with a simple one-step binding model. J Biol Chem, 2001 Jun 29, 276(26), 23607 - 15 Epub 2001 Apr 20. SopE acts as an Rab5-specific nucleotide exchange factor and recruits non-prenylated Rab5 on Salmonella-containing phagosomes to promote fusion with early endosomes; Mukherjee K et al.; Rab-GTPase regulates the fusion between two specific vesicles . It is well documented that, for their biological function, Rab proteins need to be prenylated for attachment to the vesicle membrane . In contrast, we showed in the present investigation that SopE, a type III secretory protein of Salmonella, translocates onto Salmonella-containing phagosomes (LSP) and mediates the recruitment of non-prenylated Rab5 (Rab5:DeltaC4) on LSP in GTP form . Simultaneously, SopE present in infected cell cytosol acts as an Rab5-specific exchange factor and converts the inactive Rab-GDP to the GTP form . The non-prenylated Rab5 subsequently promoted efficient fusion of LSP with early endosomes . This is the first demonstration that a prenylation-deficient Rab protein retains biological activity and can promote vesicle fusion, if it is recruited on the membrane by some other method. Asian Pac J Allergy Immunol, 2000 Dec, 18(4), 209 - 14 Nitric oxide production by murine spleen cells stimulated with Porphyromonas gingivalis-derived lipopolysaccharide; Sosroseno W; The aim of the present study was to determine whether Porphyromonas gingivalis-lipopolysaccharide (Pg-LPS) may stimulate nitric oxide (NO) production by murine spleen cells . Spleen cells derived from Balb/c mice were cultured in the presence of Pg-LPS or LPS from Salmonella Typhosa . The cell were also cultured in the presence of Pg-LPS with or without L-arginine, L-arginine plus NG-monomethyl-L-arginine (NMMA), or IFN-gamma . Furthermore, the plastic non-adherent spleen cells were stimulated with Pg-LPS and L-arginine . The results showed that Pg-LPS failed to stimulate splenic NO production by themselves . Exogenous L-arginine or IFN-gamma up-regulated the NO production of Pg-LPS-stimulated spleen cells, but the stimulatory effects of L-arginine were completely blocked by NMMA . It was also demonstrated that in the presence of Pg-LPS and L-arginine, splenic macrophages were the cellular source of NO . These results suggest, therefore, that P . gingivalis-LPS may induce murine splenic macrophages to produce NO in a L-arginine and an IFN-gamma-dependent mechanism. Arthritis Rheum, 2001 Apr, 44(4), 931 - 9 Expression of host defense scavenger receptors in spondylarthropathy; Seta N et al.; OBJECTIVE: Reactive arthritis (ReA) is postulated to be caused by a defective host defense against gram-negative bacteria . HLA-B27 could play a role in this process, but does not account for the many HLA-B27 negative patients . The objective of this study was to test the expression of 3 macrophage scavenger receptors (SRs) that are responsible for innate immunity against gram-negative bacteria: SR class A type I (SR-AI), SR-AII, and the macrophage receptor with collagenous structure (MARCO) . We postulate that defects in such receptors might also contribute to the host risk factors that increase the predisposition to ReA and perhaps other subtypes of spondylarthropathy (SpA) . METHODS: Peripheral blood, synovial fluid, and synovial tissue samples were obtained from patients with recent Salmonella infection, ReA, other SpA, and rheumatoid arthritis (RA) . The expression of SRs receptors was assessed by semiquantitative reverse transcriptase-polymerase chain reaction . RESULTS: Evaluation of the peripheral blood mononuclear cells (PBMC) from 4 patients who were recently infected with Salmonella, showed that PBMC from 2 patients who developed ReA expressed positive levels of MARCO, while PBMC from 2 patients who recovered from infection without sequelae did not . The synovial fluid mononuclear cells (SFMC) from some ReA patients expressed MARCO, but the levels were only moderate . The level of MARCO in the SFMC from the SpA patient group was low . In marked contrast, MARCO expression was high in almost all samples of RA SFMC . These findings also extended to synovial tissues . CONCLUSION: Expression of the host defense gene MARCO was susceptible to modulation, not only during infections, but also in the inflammatory arthritis conditions RA and SpA . MARCO is a variable to be considered as a candidate factor that might contribute to ReA. Pediatr Surg Int, 2001 Mar, 17(2-3), 215 - 7 Cecal perforation presenting as abdominal-wall necrotizing fasciitis; Sy ED et al.; The preoperative diagnosis of a cecal perforation associated with Salmonella infection as a cause of abdominal-wall necrotizing fasciitis (AWNF) is clinically difficult . Computed tomography of the abdomen is helpful, and can detect the combined presence of a pneumoscrotum and pneumoperitoneum . Its presence indicates a patent processus vaginalis, which acts as the primary route for the spread of the intra-abdominal infectious process into the abdominal wall . An exploratory laparotomy should be done to confirm the presence of intra-abdominal pathology in order to avoid delayed treatment. Blood, 2001 May 1, 97(9), 2688 - 94 Missense mutation of the interleukin-12 receptor beta1 chain-encoding gene is associated with impaired immunity against Mycobacterium avium complex infection; Sakai T et al.; Interleukin-12 (IL-12) plays an important role in the production of interferon gamma (IFN-gamma) and is essential for protection against intracellular pathogens such as Mycobacterium and Salmonella . A 31-year-old man had disseminated Mycobacterium avium complex (MAC) infection . The production of IFN-gamma by peripheral blood mononuclear cells stimulated with phytohemagglutinin (PHA-PBMCs) was found severely impaired (40.7 pg/mL compared with 833 +/- 289 pg/mL for the patient's and healthy subjects' (n = 3) PHA- PBMCs, respectively), and the patient's PHA-PBMCs completely lacked surface IL-12 receptor beta1 (IL-12Rbeta1) chain . The IL-12Rbeta1 gene transcript in his PHA-PBMCs had an R213W substitution in each allele . Family history showed that both parents were heterozygotes in the R213W substitution . Transfection of a human embryonal kidney cell line 293 (HEKC293) with wild-type IL-12Rbeta1wt gene led to cell surface IL-12Rbeta1 expression; however, no expression was seen in HEKC293 transfected with the mutated IL-12Rbeta1R213W gene . The IL-12Rbeta1 gene transcript, but no IL-12Rbeta1 protein, was detected in PHA-PBMCs and T cells, suggesting a post-translational event(s), most likely a shortened turnover of the protein . The R213W substitution was not detected in the cells of 32 healthy persons or of 25 patients with tuberculosis or MAC infection . Six amino acid substitutions (Q214R, M365T, G378R, H438Y, A525T, and G594E) were identified, but the incidences of such substitutions were not significantly different between the groups . The Q214R substitution is reportedly linked to IL-12Rbeta1 deficiency; however, the study showed that 19 and 10 of 57 Japanese and 6 and 4 of 33 healthy white persons were heterozygous and homozygous for Arg-214, respectively, suggesting that the Q214R substitution represents a polymorphism and is not related to IL-12Rbeta1 deficiency but that the R213W substitution is responsible for IL-12Rbeta1 deficiency. Food Chem Toxicol, 2001 May, 39(5), 499 - 505 Effect of pyrolysis temperature on the mutagenicity of tobacco smoke condensate; White JL et al.; Tobacco smoke aerosols with fewer mutagens in the particulate fraction may present reduced risk to the smoker . The objective of this study was to test the hypothesis that the temperature at which tobacco is pyrolyzed or combusted can affect the mutagenicity of the particulate fraction of the smoke aerosol . Tobacco smoke aerosol was generated under precisely controlled temperature conditions from 250 to 550 degrees C by heating compressed tobacco tablets in air . The tobacco aerosols generated had a cigarette smoke-like appearance and aroma . The tobacco smoke aerosol was passed through a Cambridge filter pad to collect the particulate fraction, termed the smoke condensate . Although condensates of tobacco smoke and whole cigarette mainstream smoke share many of the same chemical components, there are physical and chemical differences between the two complex mixtures . The condensates from smoke aerosols prepared at different temperatures were assayed in the Ames Salmonella microsome test with metabolic activation by rat liver S9 using tester strains TA98 and TA100 . Tobacco smoke condensates were not detectably mutagenic in strain TA98 when the tobacco smoke aerosol was generated at temperatures below 400 degrees C . Above 400 degrees C, condensates were mutagenic in strain TA98 . Similarly, condensates prepared from tobacco smoke aerosols generated at temperatures below 475 degrees C were not detectably mutagenic in strain TA100 . In contrast, tobacco tablets heated to temperatures of 475 degrees C or greater generated smoke aerosol that was detectably mutagenic as measured in TA100 . Therefore, heating and pyrolyzing tobacco at temperatures below those found in tobacco burning cigarettes reduces the mutagenicity of the smoke condensate . Highly mutagenic heterocyclic amines derived from the pyrolysis of tobacco leaf protein may be important contributors to the high temperature production of tobacco smoke Ames Salmonella mutagens . The relevance of these findings regarding cancer risk in humans is difficult to assess because of the lack of a direct correlation between mutagenicity in the Ames Salmonella test and carcinogenicity. Vaccine, 2001 Apr 30, 19(23-24), 3277 - 84 Vaccination with the glycoprotein D gene of pseudorabies virus delivered by nonpathogenic Escherichia coli elicits protective immune responses; Shiau AL et al.; Attenuated intracellular bacteria, such as Salmonella and Shigella, have been exploited to act as gene delivery vectors . In this study, we report that nonpathogenic, live Escherichia coli can be used for the delivery of DNA vaccines in vivo, leading to generation of immune responses against plasmid-encoded foreign antigens . The pseudorabies virus (PrV) DNA vaccine carrying the glycoprotein D (gD) gene delivered by E . coli was able to induce protective immune responses in mice against a lethal PrV challenge . Co-delivery of E . coli carrying plasmid DNA encoding prothymosin alpha enhanced cellular immune responses to the PrV DNA vaccine delivered by E . coli . Our results suggest that nonpathogenic E . coli may be used as a vector for DNA vaccines in veterinary uses. Prev Vet Med, 2001 May 1, 49(3-4), 175 - 90 Estimation of animal-level prevalence from pooled samples in animal production; Evers EG et al.; Often, the prevalence of an infection in the animal-production sector is determined at the group level . The prevalence at animal level (p) gives more-precise information on the infection status of the sector . This paper shows that pooled-sample data together with mathematical models allow for estimation of p . For this, model assumptions have to be made on the variation of p between groups separated in space and/or time . Formulas were derived for four models that were based on different assumptions . Model 1 assumed that p has the same value for all groups . Models 2-4 assumed that some of the groups were not infected . In addition, model 2 assumed that p has the same value for all infected groups; model 3 assumed that for an infected group, p is equal to either p(1) or p(2); and model 4 assumed that p was Beta distributed among infected groups . The models were applied to data sets on Salmonella infection in broiler flocks, including serotype data dominated by S . Hadar and S . Paratyphi B, var . Java . Based on likelihood-ratio tests, models 3 and 4 consistently fitted significantly better to the data . The applicability of model 4 is numerically bounded, related to the shape of the Beta distribution of p . Model calculations show that flock-level prevalence of Salmonella is much higher after than before slaughter . This difference (which possibly is related to different types of samples) is much smaller at the animal level . An important result of the estimation of p is that it in turn allows for an estimation of the proportion of false-negative groups--which is important in estimating the effect of veterinary or public-health measures. J Wildl Dis, 2001 Apr, 37(2), 229 - 38 Salmonelliasis in wildlife from Queensland; Thomas AD et al.; During a 20 yr period (1978 to 1998), 233 isolates of Salmonella spp . were cultured from 179 wildlife animals (representing 25 species), 32 crocodile (Crocodylus porosus) eggs and six crocodile nesting sites, and represented 59 different serotypes . Salmonella serotype Virchow, the major serotype infecting humans in north Queensland, (Australia) was common in macropodids, but was not found in reptiles and was isolated only once from cane toads (Bufo marinus) . Investigations of human cases of salmonellosis should include simultaneous studies on wild and domestic animals in contact with the case. Microb Drug Resist, 2001 Spring, 7(1), 13 - 21 Variation in clonality and antibiotic-resistance genes among multiresistant Salmonella enterica serotype typhimurium phage-type U302 (MR U302) from humans, animals, and foods; Walker RA et al.; Since 1990 multiresistant (MR) Salmonella enterica serotype Typhimurium definitive phage-type (DT) 104 (MR DT104) and closely related phage types have emerged as a worldwide health problem in humans and food animals . In this study the presence of the blaCARB-2 (ampicillin), cmlA (chloramphenicol), aadA2 (streptomycin/spectinomycin), sul1 (sulphonamide), and tetG (tetracycline) resistance genes in isolates of one such phage type, U302, have been determined . In addition blaTEM primers have been used for the detection of TEM-type beta-lactamases . Isolates have also been characterized by plasmid profile and pulsed field gel electrophoresis (PFGE) . Thirty-three of 39 isolates were positive for blaCARB-2, cmlA, aadA2, sul1 and tetG, four for blaTEM, aadA2 and sul1, one for aadA2 and sul1, and one for blaTEM only . blaTEM-mediated ampicillin resistance was transferred to Escherichia coli K12 from three isolates along with other resistance markers, including resistance to chloramphenicol, streptomycin, spectinomycin, sulphonamides, and tetracyclines . Strains carried up to 6 plasmids and 34 plasmid profiles were identified . Although the majority of strains (33/39) produced a PFGE profile identical to that predominant in MR DT104, six different patterns were generated demonstrating the presence of various clones within MR U302 . The results show that the majority of the MR U302 strains studied possessed the same antibiotic resistance genes as MR DT104 . However, isolates with distinctive PFGE patterns can have different mechanisms of resistance to ampicillin, chloramphenicol, streptomycin, sulphonamides, and tetracyclines . Such resistance genes may be borne on transmissible plasmids. Int J Med Microbiol, 2001 Mar, 290(8), 707 - 18 Virulence in the chick model and stress tolerance of Salmonella enterica serovar Orion var . 15+; La Ragione RM et al.; Three Salmonella enterica serovar Orion var . 15+ isolates of distinct provenance were tested for survival in various stress assays . All were less able to survive desiccation than a virulent S . Enteritidis strain, with levels of survival similar to a rpoS mutant of the S . Enteritidis strain, whereas one isolate (F3720) was significantly more acid tolerant . The S . Orion var . 15+ isolates were motile by flagellae and elaborated type-1 and curli-like fimbriae; surface organelles that are considered virulence determinants in Salmonella pathogenesis . Each adhered and invaded HEp-2 tissue culture cells with similar proficiency to the S . Enteritidis control but were significantly less virulent than S . Enteritidis in the one-day-old and seven-day-old chick model . Given an oral dose of 1 x 10(3) cfu to one-day-old chicken, S . Orion var . 15+ isolates colonised 25% of liver and spleens examined at 24 h whereas S . Enteritidis colonised 100% of organs by the same with the same dose . Given an oral dose of 1 x 10(7) cfu at seven-day old, S . Orion var . 15+ failed to colonise livers and spleens in any bird examined at 24 h whereas S . Enteritidis colonised 50% of organs by the same with the same dose . Based on the number of internal organs colonised, one of the three S . Orion var . 15+ isolates tested (strain F3720) was significantly more invasive than the other two (B1 and B7) . Also, strain F3720 was shed less than either B1 or B7 supporting the concept that there may be an inverse relationship between the ability to colonise deep tissues and to persist in the gut . These data are discussed in the light that S . Orion var . 15+ is associated with sporadic outbreaks of human infection rather than epidemics. Scand J Immunol, 2001 May, 53(5), 437 - 42 Vaccination against Helicobacter pylori in non-human primate models and humans; Lee CK; Several vaccination studies have been performed in monkeys and humans testing the feasibility of prophylactic and therapeutic immunizations against Helicobacter pylori . The monkey studies showed that immune responses were induced by oral vaccination with the mucosal adjuvant LT (Escherichia coli heat-labile enterotoxin), parenteral administration with a cationic lipid adjuvant, and by mucosal priming followed by parenteral boosts . Both prophylactic and therapeutic activities were demonstrated in monkeys, providing a strong impetus for human vaccine trials . Preliminary studies in humans were undertaken in order to identify a tolerable dose of LT adjuvant or to test the effectiveness of mutant atoxic LT adjuvants . The results from these preliminary studies suggest that native LT causes diarrhoea at doses required for adjuvanticity while a mutant LT does not . In one study in which infected human subjects were vaccinated with orally administered urease antigen with native LT, there was a modest reduction in the level of H . pylori gastric colonization . A second clinical study employing H . pylori whole cell antigen and a mutant LT in infected subjects showed immune responses and although the subjects remained infected, the study was not designed to measure reduction in H . pylori colonization . Recombinant Salmonella expressing urease and other H . pylori antigens have been effective in mice (see accompanying Frontlines Topic Review by John O . Nedrud {1}), but monkey studies are not possible because of host range restriction . Human trials of parenteral immunization, mucosal immunization with mutant LT and live Salmonella vectors are needed to fully assess the ability of vaccines to prevent or treat H . pylori infections. J Appl Microbiol, 2001 Apr, 90(4), 494 - 507 Antimicrobial properties of phenolic compounds from berries; Puupponen-Pimia R et al.; AIMS: To investigate the antimicrobial properties of phenolic compounds present in Finnish berries against probiotic bacteria and other intestinal bacteria, including pathogenic species . METHODS AND RESULTS: Antimicrobial activity of pure phenolic compounds representing flavonoids and phenolic acids, and eight extracts from common Finnish berries, was measured against selected Gram-positive and Gram-negative bacterial species, including probiotic bacteria and the intestinal pathogen Salmonella . Antimicrobial activity was screened by an agar diffusion method and bacterial growth was measured in liquid culture as a more accurate assay . Myricetin inhibited the growth of all lactic acid bacteria derived from the human gastrointestinal tract flora but it did not affect the Salmonella strain . In general, berry extracts inhibited the growth of Gram-negative but not Gram-positive bacteria . These variations may reflect differences in cell surface structures between Gram-negative and Gram-positive bacteria . Cloudberry, raspberry and strawberry extracts were strong inhibitors of Salmonella . Sea buckthorn berry and blackcurrant showed the least activity against Gram-negative bacteria . CONCLUSION: Different bacterial species exhibit different sensitivities towards phenolics . SIGNIFICANCE AND IMPACT OF THE STUDY: These properties can be utilized in functional food development and in food preservative purposes. J Food Prot, 2001 Apr, 64(4), 542 - 5 Incidence of Salmonella in five Swedish slaughterhouses; Thorberg BM et al.; Five Swedish slaughterhouses where pig slaughter takes place were sampled and tested for Salmonella . Each slaughterhouse was visited six times, and sampling was done repeatedly at specific points in the slaughter line during the day . Both sampling of pork carcasses and the slaughterhouse environment was done . This study was part of a larger European project, entitled Salmonella in Pork (Salinpork), with the aim of identifying specific risk points or risk factors associated with Salmonella contamination that contribute to health hazards for humans . During the study, a total of 3,388 samples from the five slaughterhouses were collected and cultured for Salmonella . All of the samples were culture negative for Salmonella. J Food Prot, 2001 Apr, 64(4), 442 - 50 Evaluation of volatile chemical treatments for lethality to Salmonella on alfalfa seeds and sprouts; Weissinger WR et al.; A study was done to evaluate natural volatile compounds for their ability to kill Salmonella on alfalfa seeds and sprouts . Acetic acid, allyl isothiocyanate (AIT), trans-anethole, carvacrol, cinnamic aldehyde, eugenol, linalool, methyl jasmonate, and thymol were examined for inhibitory and lethal activity against Salmonella by exposing inoculated alfalfa seeds to compounds (1,000 mg/liter of air) for 1, 3, and 7 h at 60 degrees C . Only acetic acid, cinnamic aldehyde, and thymol caused significant reductions in Salmonella populations (>3 log10 CFU/g) compared with the control (1.9 log10 CFU/g) after treatment for 7 h . Treatment of seeds at 50 degrees C for 12 h with acetic acid (100 and 300 mg/liter of air) and thymol or cinnamic aldehyde (600 mg/liter of air) significantly reduced Salmonella populations on seeds (>1.7 log10 CFU/g) without affecting germination percentage . Treatment of seeds at 50 degrees C with AIT (100 and 300 mg/liter of air) and cinnamic aldehyde or thymol (200 mg/liter of air) did not significantly reduce populations compared with the control . Seed germination percentage was largely unaffected by treatment with gaseous acetic acid, AIT, cinnamic aldehyde, or thymol for up to 12 h at 50 degrees C . The number of Salmonella on seeds treated at 70 degrees C for 80 min with acetic acid (100 and 300 mg/liter of air), AIT (100 mg/liter of air), and cinnamic aldehyde and thymol (600 mg/liter of air) at water activity (a(w)) 0.66 was not significantly different than the number inactivated on seeds at a(w) 0.49 . Acetic acid at 200 and 500 mg/liter of air reduced an initial population of 7.50 log10 CFU/g of alfalfa sprouts by 2.33 and 5.72 log10 CFU/g, respectively, within 4 days at 10 degrees C . whereas AIT at 200 and 500 mg/liter of air reduced populations to undetectable levels; however, both treatments caused deterioration in sensory quality . Treatment of sprouts with 1 or 2 mg of AIT per liter of air adversely affected sensory quality but did not reduce Salmonella populations after 11 days of exposure at 10 degrees C. Apoptosis, 2000 Dec, 5(6), 509 - 14 Protection of apoptotic cell death by protein A; Ray PK et al.; The word "Apoptosis" or pragrammed cell death is described as the ultimate end of multiple cellular events converging from numerous initiating events to the ultimate death of a cell or organism . Several processes, such as initiation of death signals at the plasma membrane, expression of pro-apoptotic oncoproteins, activation of death proteases, endonucleases etc., that ultimately coalesce to a common irreversible execution phase, lead to cell demise . Counteracting the death signals are cell survival factors . A balance between the cell death and cell survival factors plays a major role in the decision making process as to whether a cell should die or must live . It is, therefore, hypothesized that if the balance can be shifted in favor of cell survival, one might be able to arrest the aging process, save the injured cells or else if the balance is shifted toward cell-kill it might help destroy tumors and other undesirable cells . Protein A (PA) of Staphylococcus aureus has been found to have multifarious biological response modifying properties . It has been shown to possess anti-tumor, antitoxic, anti-parasitic and antifungal activities . It also acts as a potent immunostimulator . PA can protect bone marrow progenitor cells from zidovudin(AZT)-induced apoptosis and can stimulate immunocyte proliferation, thereby helping to replenish/restore the depleted hematopoietic cell pool . Such ability to replenish hematopoietic cells is a common property of PA observed against a number of toxic drugs/chemicals, such as cyclophosphamide, benzene, aflatoxin, salmonella endotoxin, etc . Interestingly, it was further demonstrated in our laboratory that PA can selectively kill tumor cells without affecting normal cells of the host . A search for the mechanisms of PA action revealed that this bacterial protein could shift the balance between pro- and anti-apoptotic proteins in favor of survival in normal cells, but in favor of cell death in tumor cells at a particular dose level . This unique property of PA suggests that controlled use of such type of Biological Response Modifier might help in controlling both cell growth and death phenomena. Trends Microbiol, 2001 Mar, 9(3), 137 - 44 Bacteriophage-bacteriophage interactions in the evolution of pathogenic bacteria; Boyd EF et al.; Many bacteriophages carry virulence genes encoding proteins that play a major role in bacterial pathogenesis . Recently, investigators have identified bacteriophage-bacteriophage interactions in the bacterial host cell that also contribute significantly to the virulence of bacterial pathogens . The relationships between the bacteriophages pertain to one bacteriophage providing a helper function for another, unrelated bacteriophage in the host cell . Accordingly, these interactions can involve the mobilization of bacteriophage DNA by another bacteriophage, for example in Escherichia coli, Vibrio coli and Staphylococcus aureus; the host receptor for one bacteriophage being encoded by another, as found in V . cholerae; and the presence of one bacteriophage potentiating the virulence properties of another bacteriophage, as found in V . cholerae and Salmonella enterica. Antimicrob Agents Chemother, 2001 May, 45(5), 1337 - 42 Synergy of histone-derived peptides of coho salmon with lysozyme and flounder pleurocidin; Patrzykat A et al.; Recent research has identified endogenous cationic antimicrobial peptides as important factors in the innate immunity of many organisms, including fish . It is known that antimicrobial activity, as well as lysozyme activity, can be induced in coho salmon (Oncorhynchus kisutch) mucus after exposure of the fish to infectious agents . Since lysozyme alone does not have antimicrobial activity against Vibrio anguillarum and Aeromonas salmonicida, a four-step protein purification protocol was used to isolate and identify antibacterial fractions from bacterially challenged coho salmon mucus and blood . The purification consisted of extraction with hot acetic acid, extraction and concentration on a C(18) cartridge, gel filtration, and reverse-phase chromatography on a C(18) column . N-terminal amino acid sequence analyses revealed that both the blood and the mucus antimicrobial fractions demonstrated identity with the N terminus of trout H1 histone . Mass spectroscopic analysis indicated the presence of the entire histone, as well as fragments thereof, including a 26-amino-acid N-terminal segment . These fractions inhibited the growth of antibiotic-supersuscptible Salmonella enterica serovar Typhimurium, as well as A . salmonicida and V . anguillarum . Synthetic peptides identical to the N-terminally acetylated or C-terminally amidated 26-amino-acid fragment were inactive in antimicrobial assays, but they potentiated the antimicrobial activities of the flounder peptide pleurocidin, lysozyme, and crude lysozyme-containing extracts from coho salmon . The peptides bound specifically to anionic lipid monolayers . However, synergy with pleurocidin did not appear to occur at the cell membrane level . The synergistic activities of inducible histone peptides indicate that they play an important role in the first line of salmon defenses against infectious pathogens and that while some histone fragments may have direct antimicrobial effects, others improve existing defenses. Saudi Med J, 2001 Feb, 22(2), 129 - 32 Serogroups and antimicrobial susceptibility of non-typhoidal salmonellas in children; Al-Zamil FA et al.; OBJECTIVE: To update knowledge regarding the pattern of Serogroups and antimicrobial susceptibility of Salmonellas causing gastroenteritis in children at the King Khalid University Hospital in Riyadh, Saudi Arabia during the period of 1st April 1996 to 30th September 1999 . METHODS: The case records of 416 children, from whom Salmonella species were isolated from stool cultures between April 1996 and September 1999 were reviewed . The isolates and susceptibility of these Salmonella were carried out accordingly to standard microbiological methods . RESULTS: During a period of 3 and 1/2 years a total of 412 non-typhoidal Salmonellas were isolated from stool cultures of 416 children who presented to King Khalid University Hospital complaining of gastroenteritis . The majority of these children (70%) belonged to the age group 0-4 years . Eighty seven percent of the Salmonella isolates were Serogroup D1, B and C1 . The Serogroups and antimicrobial susceptibility of these Salmonellas differed from those previously reported from this country and other parts of the world . CONCLUSION: Salmonella gastroenteritis is an important clinical condition in infants and children in the Kingdom of Saudi Arabia . Salmonella Serogroups D1, B and C predominate as causative agents of this condition . Most of the salmonella serogroups isolated in this study were highly susceptible to commonly used antimicrobial agents but ampicillin showed a rising resistance pattern . This may make it unsuitable therapy for Salmonella gastroenteritis. Biochemistry, 2001 Mar 27, 40(12), 3700 - 9 Kinetic and mutagenic characterization of the chromosomally encoded Salmonella enterica AAC(6')-Iy aminoglycoside N-acetyltransferase; Magnet S et al.; The chromosomally encoded aminoglycoside N-acetyltransferase, AAC(6')-Iy, from Salmonella enterica confers resistance toward a number of aminoglycoside antibiotics . The structural gene was cloned and expressed and the purified enzyme existed in solution as a dimer of ca . 17 000 Da monomers . Acetyl-CoA was the preferred acyl donor, and most therapeutically important aminoglycosides were substrates for acetylation . Exceptions are those aminoglycosides that possess a 6'-hydroxyl substituent (e.g., lividomycin) . Thus, the enzyme exhibited regioselective and exclusive acetyltransferase activity to 6'-amine-containing aminoglycosides . The enzyme exhibited Michaelis-Menten kinetics for some aminoglycoside substrates but "substrate activation" with others . Kinetic studies supported a random kinetic mechanism for the enzyme . The enzyme was inactivated by iodoacetamide in a biphasic manner, with half of the activity being lost rapidly and the other half more slowly . Tobramycin, but not acetyl-CoA, protected against inactivation . Each of the three cysteine residues (C70, C109, C145) in the wild-type enzyme were carboxamidomethylated by iodoacetamide . Cysteine 109 in AAC(6')-Iy is conserved in 12 AAC(6') enzyme sequences of the major class I subfamily . Surprisingly, mutation of this residue to alanine neither abolished activity nor altered the biphasic inactivation by iodoacetamide . The maximum velocity and V/K values for a number of aminoglycosides were elevated in this single mutant, and the kinetic behavior of substrates exhibiting linear vs nonlinear kinetics was reversed . Cysteine 70 in AAC(6')-Iy is either a cysteine or a threonine residue in all 12 AAC(6') enzymes of the major class I subfamily . The double mutant, C109A/C70A, was not inactivated by iodoacetamide . The double mutant exhibited large increases in the K(m) values for both acetyl-CoA and aminoglycoside substrates, and all aminoglycoside substrates exhibited Michaelis-Menten kinetics . Solvent kinetic isotope effects on V/K were normal for the WT enzyme and inverse for the double mutant . We discuss a chemical mechanism and the likely rate-limiting steps for both the wild-type and mutant forms of the enzyme. Poult Sci, 2001 Apr, 80(4), 515 - 21 Thermal inactivation of Salmonella senftenberg and Listeria innocua in ground chicken breast patties processed in an air convection oven; Murphy RY et al.; Ground chicken breast patties were thermally processed in a lab-scale air convection oven at air temperatures of 163, 177, 190, 204, or 218 C to final patty center temperatures of 50, 55, 60, 65, 70, 75, or 80 C . The cooking time increased with increasing product temperature and decreased with increasing oven air temperature . Prior to thermal processing, approximately 7 log10(cfu/g) of Salmonella senftenberg and Listeria innocua were inoculated into the chicken patties . Survival of S . senftenberg and L . innocua decreased with increasing patty temperature . After the patties were processed to a final center temperature of 70 to 80 C, 1 to 4 log10 (cfu/g) of S . senftenberg and 3 to 5 log10(cfu/g) of L . innocua were detected in the cooked patties . A significant difference in the thermal inactivation of S . senftenberg and L . innocua was obtained between the chicken patties cooked in an air convection oven and the patties cooked in a water bath . More surviving S . senftenberg and L . innocua were found in the patties cooked in an air convection oven than in the patties cooked in a water bath. Eur J Epidemiol, 2000, 16(9), 861 - 8 A review of the Salmonellosis surveillance systems in Italy: evolution during the course of time within the international framework; Scuderi G; This paper focuses on the history of the two systems that have been adopted in Italy for the surveillance of Salmonellosis and describes their respective characteristics . Both systems have been subsequently modified: (1) The National Laboratory-based Surveillance System (NLSS) which was created in 1967 for Enteropathogenic Bacteria and subsequently, in 1992, became part of the European computerised Laboratory-based Surveillance System of Salmonellae isolates, the SALM-NET (Salmonella network); (2) The National Infectious Disease Reporting System (NIDRS) which was set up in the 1930s, revised in 1990 and has been used, since 1994, along with the Infectious Disease Informative System (IDIS) . The results obtained with the different surveillance systems are presented: (1) The number of isolates from the laboratory surveillance from 1973 to 1997 are described . Total Salmonellae isolates have a slope with an increasing trend from 4372 isolates in 1973 to 15,041 isolates in 1988 drastically dropping to 5479 isolates in 1990 and increasing again to 13,596 isolates in 1993 . Attention is given particularly to the epidemiology of S . enteritidis in Italy which increased progressively since 1982 (225 isolates) to 5435 isolates in 1994 . S . typhimurium showed a slightly increasing trend in the period 1973-1988 (from 1694 to 3383 isolates) then decreased for reaching again previous levels . S . typhi showed a marked reduction from 573 isolates in 1973 to 33 isolates in 1996 . On the contrary, other less frequent serotypes increased . (2) The number of cases of Salmonellosis reported during 1971-1997 are also presented . Other Infections by Salmonellae increased from 12,516 cases in 1976 (renamed Non Typhoidal Salmonellosis in 1990) to more than 20,000 cases in 1992 . The number of cases of Typhoid Fever and Infections by S . paratyphi are also described . Particular attention has to be paid to the parallel trends of Salmonellosis using both surveillance systems: number of isolates and number of cases, particularly comparing Other Infections by Salmonellae and total Salmonellae isolates: after the 1992-1993 peak, an initial decrease was observed. Turk J Pediatr, 2001 Jan-Mar, 43(1), 85 - 7 Sepsis and multiple brain abscesses caused by Salmonella paratyphi B in an infant: successful treatment with sulbactam-ampicillin and surgical drainage; Yildiran A et al.; Abscess formation by Salmonella species is an uncommon but significant manifestation of salmonellosis, because this type of infection has high morbidity and mortality rates and is a potential nosocomial hazard . In infants, history of consumption of contaminated water should be especially quired . We report a case who had sepsis and multiple brain abscesses due to Salmonella paratyphi B and who responded to sulbactam-ampicillin (SAM) therapy . Sulbactam-ampicillin combination may be preferable due to its immunomodulator effect. EMBO J, 2001 Apr 17, 20(8), 1840 - 9 Expression of microbial virulence proteins in Saccharomyces cerevisiae models mammalian infection; Lesser CF et al.; Bacterial virulence proteins that are translocated into eukaryotic cells were expressed in Saccharomyces cerevisiae to model human infection . The subcellular localization patterns of these proteins in yeast paralleled those previously observed during mammalian infection, including localization to the nucleus and plasma membrane . Localization of Salmonella SspA in yeast provided the first evidence that SspA interacts with actin in living cells . In many cases, expression of the bacterial virulence proteins conferred genetically exploitable growth phenotypes . In this way, Yersinia YopE toxicity was demonstrated to be linked to its Rho GTPase activating protein activity . YopE blocked polarization of the yeast cytoskeleton and cell cycle progression, while SspA altered polarity and inhibited depolymerization of the actin cytoskeleton . These activities are consistent with previously proposed or demonstrated effects on higher eukaryotes and provide new insights into the roles of these proteins in pathogenesis: SspA in directing formation of membrane ruffles and YopE in arresting cell division . Thus, study of bacterial virulence proteins in yeast is a powerful system to determine functions of these proteins, probe eukaryotic cellular processes and model mammalian infection. Vet Microbiol, 2001 May 21, 80(2), 171 - 84 Salmonella seroprevalence at the population and herd level in pigs in The Netherlands; van der Wolf PJ et al.; The aim of this study was to provide baseline data on the population and herd Salmonella seroprevalence in sows and finishers . For the population estimates in 1996 and 1999 and the herd prevalences for sows and gilts, blood samples from swine vesicular disease (SVD) and pseudorabies monitoring programmes were used and tested in an indirect Salmonella enzyme-linked immunosorbent assay (ELISA) . The herd prevalence for finishers was determined using blood samples collected at two slaughterhouses.The population prevalence for finishers in 1996 and 1999 was 23.7 and 24.5%, respectively, and for sows 40.5 and 60.4%, respectively . The prevalence in free range (FR) finishers was significantly higher (44.6%) than in intensively housed finishers in 1999, identifying a hazard group for possible extra pork and pork product contamination . Of 406 finishing herds, 9% were completely seronegative for Salmonella (cut-off OD%>10) . Of these 406 finishing herds, 69.7% had Salmonella-status I (low prevalence), 21.7% status II (moderate prevalence) and 8.6% status III (high prevalence) (cut-off OD%>40) . In 46 multiplying sow herds, 20 breeding sow herds and 20 matching replacement gilt herds, the average herd prevalences were 54, 44.4 and 19.3%, respectively . Two gilt herds were completely seronegative . The prevalence in the gilt herds was never higher than in the matching breeding sow herds . Agreement on methodology and calibration of ELISA tests would make these results comparable between countries and is a prerequisite for a co-ordinated and integrated program to reduce Salmonella in pork in the European Union. Vet Microbiol, 2001 May 21, 80(2), 139 - 48 Typing of Salmonella enterica subsp . enterica serovar Mbandaka isolates; Hoszowski A et al.; Recently, Salmonella enterica subsp . enterica serovar Mbandaka (S . Mbandaka) has gained some importance in the epidemiology of salmonellosis in Poland . Since biotyping, resistance typing, and plasmid profiling were insufficient for strain differentiation, genome macrorestriction by means of pulse-field gel electrophoresis (PFGE) was applied and proved to be the method of choice in S . Mbandaka epidemiological studies . XbaI and BcuI macrorestriction produced 15 and 14 pulse-field profiles (PFP), respectively, but in the case of each enzyme one profile was prevalent . When macrorestriction profiles were combined, a total 24 patterns were found . Based on the similarity of the profiles, four clonal lineages were identified . One clonal lineage contained the majority of poultry, feed and human isolates . Poultry was concluded to be an important source of S . Mbandaka for humans in Poland . Complementary use of various typing techniques improved efficacy of epidemiological studies giving possibility to subdivide S . Mbandaka into 35 types and the index of discrimination reached 0.947. Biochemistry, 2001 Apr 17, 40(15), 4703 - 13 In vitro conversion of propionate to pyruvate by Salmonella enterica enzymes: 2-methylcitrate dehydratase (PrpD) and aconitase Enzymes catalyze the conversion of 2-methylcitrate to 2-methylisocitrate; Horswill AR et al.; Salmonella enterica serovar Typhimurium LT2 catabolizes propionate through the 2-methylcitric acid cycle, but the identity of the enzymes catalyzing the conversion of 2-methylcitrate into 2-methylisocitrate is unclear . This work shows that the prpD gene of the prpBCDE operon of this bacterium encodes a protein with 2-methylcitrate dehydratase enzyme activity . Homogeneous PrpD enzyme did not contain an iron-sulfur center, displayed no requirements for metal cations or reducing agents for activity, and did not catalyze the hydration of 2-methyl-cis-aconitate to 2-methylisocitrate . It was concluded that the gene encoding the 2-methyl-cis-aconitate hydratase enzyme is encoded outside the prpBCDE operon . Computer analysis of bacterial genome databases identified the presence of orthologues of the acnA gene (encodes aconitase A) in a number of putative prp operons . Homogeneous AcnA protein of S . enterica had strong aconitase activity and catalyzed the hydration of the 2-methyl-cis-aconitate to yield 2-methylisocitrate . The purification of this enzyme allows the complete reconstitution of the 2-methylcitric acid cycle in vitro using homogeneous preparations of the PrpE, PrpC, PrpD, AcnA, and PrpB enzymes . However, inactivation of the acnA gene did not block growth of S . enterica on propionate as carbon and energy source . The existence of a redundant aconitase activity (encoded by acnB) was postulated to be responsible for the lack of a phenotype in acnA mutant strains . Consistent with this hypothesis, homogeneous AcnB protein of S . enterica also had strong aconitase activity and catalyzed the conversion of 2-methyl-cis-aconitate into 2-methylisocitrate . To address the involvement of AcnB in propionate catabolism, an acnA and acnB double mutant was constructed, and this mutant strain cannot grow on propionate even when supplemented with glutamate . The phenotype of this double mutant indicates that the aconitase enzymes are required for the 2-methylcitric acid cycle during propionate catabolism. Int J Food Microbiol, 2001 Mar 20, 64(3), 401 - 5 Survival of Escherichia coli O157:H7 and Salmonella on chill-stored vacuum or carbon dioxide packaged primal beef cuts; Dykes GA et al.; The ability of two Escherichia coli O157:H7 strains (E27, a cattle isolate, and B6-914 gfp-91, a fluorescent marker strain) and two Salmonella serotypes (S . typhimurium and S . brandenberg) to survive on chilled preservatively packaged primal beef cuts was examined . Each of the strains was inoculated separately at two dilution levels (10(3) and 10(5) cfu g(-1)) onto 500 g beef steaks, packaged under vacuum or 100% carbon dioxide, and stored, with uninoculated controls, for 6 weeks at - 1.5 degrees C, then for 2 weeks at 4 degrees C . Bacterial numbers were determined by dilution and incubation at 37 degrees C for 24 h on either Sorbitol McConkey Agar or Xylose Lysine Desoxycholate Agar for E . coli O157:H7 and Salmonella samples, respectively . Counts were corrected for background growth and their accuracy checked using immunological tests . Fluorescent E . coli O157:H7 B6-914 gfp-91 was also counted under ultra-violet light . No significant changes in numbers of the E . coli O157:H7 or Salmonella strains occurred during storage at either - 1.5 or 4 degrees C packaged under either vacuum or carbon dioxide . The ability of these pathogens to survive standard preservative packaging conditions is different from that reported from their generic counterparts and therefore a cause for public health concern. Int J Food Microbiol, 2001 Mar 20, 64(3), 395 - 9 Detection of Salmonella enteritidis in shell and liquid eggs using enrichment and plating; Hara-Kudo Y et al.; Detection methods using various enrichment and plating media and immunoconcentration for Salmonella enteritidis in shell and liquid eggs were evaluated . For liquid egg samples naturally contaminated with S . enteritidis, pre-enrichment in 225 ml of buffered peptone water with cysteine followed by selective enrichment in 10 ml of tetrathionate broth was the superior, resulting in the detection of S . enteritidis in all samples on six of the seven types of selective agar substrate investigated . This enrichment procedure also enabled detection of S . enteritidis in most of artificially inoculated shell egg and pasteurized liquid egg samples. Int J Food Microbiol, 2001 Mar 20, 64(3), 387 - 93 Evaluation of motility enrichment on modified semi-solid Rappaport-Vassiladis medium (MSRV) for the detection of Salmonella in foods; Worcman-Barnink D et al.; The detection and identification of Salmonella spp . is still troublesome and time consuming to the food industry . Employing the modified semi-solid Rappaport-Vassiliadis medium (MSRV), presumptive results for Salmonella can be obtained in 48 h, representing an interesting alternative to the standard methods . The specificity and sensitivity of the MSRV method were evaluated in this research . The efficiency of this method was also compared with the methodology recommended by the US Food and Drug Administration (FDA) using bismuth sulfite agar, XLT4 agar and Rambach agar . A total of 146 food samples comprised of 41 chicken thighs, 35 Brazilian fresh pork sausages, 35 samples of cocoa powder and/or granulated cocoa and 35 samples of grated fresh coconut, were examined . Overall, the rapid method (direct + indirect) and the standard culture detected 96.1% and 84.6% of the positive samples, respectively . No Salmonella was detected in the coconut or cocoa samples by any of the methods . Eighteen (43.9%) chicken thigh samples were contaminated with the microorganism . The rapid method (direct + indirect) and the standard culture detected 94.4% and 88.9% of these, respectively . Salmonella was detected in eight (22.8%) fresh pork sausage samples . The MSRV method detected Salmonella in all eight samples, while the standard gave positive results in six (75%) . When compared with the standard method, the indirect method showed 86.4% sensitivity and 96.8% specificity, while the direct MSRV showed a sensitivity of 71.4% and specificity of 99.2% . Combined, both MSRV methods showed 95.5% sensitivity and 96.8% specificity . The MSRV medium also reduces the time necessary for the isolation of Salmonella from foods. Int J Food Microbiol, 2001 Mar 20, 64(3), 237 - 45 Characterization of south african isolates of Salmonella enteritidis by phage typing, numerical analysis of RAPD-PCR banding patterns and plasmid profiles; Mare L et al.; Eleven of the 33 strains of Salmonella enteritidis (S.E.) included in this study belonged to phage type 34 . Six strains belonged to phage type 14, six strains to phage type 4 and four strains to phage type 7 . The remaining six strains belonged to phage types 35, 1, 24var (a variation of phage type 24), 9a, 1b and an unknown phage type . The majority of S.E . phage type 34 strains (eight of the 11) grouped at R2 > or =0.45 into one RAPD-PCR cluster with two strains of phage types 4, a strain of phage type 24var and a strain of phage type 9a, indicating that they consist of a genetically heterogeneous collection of strains . Two of the remaining three phage type 34 strains grouped into two different clusters, well separated from the other phage type 34 strains . One strain of phage type 34 was genetically diverse and did not cluster with any of the strains included in this study . Three of the phage type 14 strains grouped into cluster 11 at R2 > or =0.72, suggesting that they are genetically closely related . However, the remaining three strains of phage type 14 grouped into two separate clusters . Strains of phage types 7, 35, and 1 grouped in one cluster at R2 > or = 0.55 . Our results clearly indicated that S.E . strains of the same phage type are not always genetically related . On the other hand, strains of a high genetic relatedness classified as different phage types . No specific plasmid profile could be linked to any of the phage types . Based on results obtained by LD50 virulence tests, strains containing the 38 MDa plasmid are more virulent compared to strains which do not contain the plasmid. Inflammation, 2001 Feb, 25(1), 7 - 15 Differential activation of signal transduction pathways mediating phagocytosis, oxidative burst, and degranulation by chicken heterophils in response to stimulation with opsonized Salmonella enteritidis; Kogut MH et al.; The activation of signal transduction pathways is required for the expression of functional enhancement of cellular activities . In the present studies, initial attempts were made to identify the signal transduction factors involved in activating phagocytosis, generation of an oxidative burst, and degranulation by heterophils isolated from neonatal chickens in response to opsonized Salmonella enteritidis (opsonized SE) . Peripheral blood heterophils were isolated and exposed to known inhibitors of signal transduction pathways for either 20 min (staurosporin, genistein, or verapamil) or 120 min (pertussis toxin) at 39 degrees C . The cells were then stimulated for 30 min at 39 degrees C with opsonized SE . Phagocytosis, luminol-dependent chemoluminescence (LDCL), and beta-D glucuronidase release were then evaluated in vitro . The G-protein inhibitor pertussin toxin markedly inhibited (>80%) phagocytosis of opsonized SE . Both the protein kinase inhibitor (staurosporin) and calcium channel inhibitor (verapamil) reduced phagocytosis in a dose response manner . Genistein, a tyrosine kinase inhibitor, had no effect on phagocytosis . Staurosporin had a marked inhibitory effect on LDCL (>90%) while genistein had a dose responsive inhibition on LDCL . Both verapamil (40-45%) and pertussin toxin (50-55%) had a statistically significant, but less biologically significant effect on LDCL . Genistein significantly reduced the degranulation (78-81%) of heterophils by opsonized SE . Staurosporin also reduced degranulation by 43-50%, but neither verapamil nor pertussis toxin had a significant effect on degranulation . These findings demonstrate that distinct signal transduction pathways differentially regulate the stimulation of the functional activities of avian heterophils . Pertussin toxin-sensitive, Ca++-dependent G-proteins appear to regulate phagocytosis of opsonized SE, protein kinase C-dependent, tyrosine kinase-dependent protein phosphorylation plays a major role in LDCL, and tyrosine kinase(s)-dependent phosphorylation regulates primary granule release. Microbiol Immunol, 2001, 45(2), 149 - 58 Vi-Suppressed wild strain Salmonella typhi cultured in high osmolarity is hyperinvasive toward epithelial cells and destructive of Peyer's patches; Zhao L et al.; Salmonella typhi GIFU10007-3 which lost a viaB locus on its chromosome became highly invasive in our previous study . To investigate the phenomenon, we controlled Vi expression in wild strain S . typhi GIFU10007, and studied the invasive phenotype both in vitro and in vivo . When the wild strain of S . typhi was cultured in 300 mM NaCl containing Luria-Bertani broth (LBH), the expression of Vi antigen was suppressed, but secretion of invasion proteins (SipC, SipB and SipA) was increased . In this condition, wild strain S . typhi became highly invasive toward both epithelial cells and M cells of rat Peyer's patches . When GIFU10007 was cultured under conditions of high osmolarity, the bacteria disrupted Peyer's patches and induced massive bleeding in these structures only 20 min after inoculation into the ileal loop . In contrast, Vi-encapsulated wild strain GIFU10007 cultured under low osmolarity was not destructive, even after 60 min . To understand the role of the type III secretion system under conditions of high osmolarity, we knocked out the invA and sipC genes of both GIFU10007 and GIFU10007-3 . Neither invA nor sipC mutants could invade epithelial cells or M cells in a high osmolarity environment . Our data show that the highly invasive phenotype was only expressed when the wild strain S . typhi was cultured under high osmolarity, which induced a state of Vi suppression, and in the presence of the type III secretion system. J Bacteriol, 2001 May, 183(9), 2852 - 8 Low-molecular-weight plasmid of Salmonella enterica serovar Enteritidis codes for retron reverse transcriptase and influences phage resistance; Rychlik I et al.; Retron reverse transcriptases are unusual procaryotic enzymes capable of synthesis of low-molecular-weight DNA by reverse transcription . All of the so-far-described DNA species synthesized by retron reverse transcriptases have been identified as multicopy single-stranded DNA . We have shown that Salmonella enterica serovar Enteritidis is also capable of synthesis of the low-molecular-weight DNA by retron reverse transcriptase . Surprisingly, Salmonella serovar Enteritidis-produced low-molecular-weight DNA was shown to be a double-stranded DNA with single-stranded overhangs (sdsDNA) . The sdsDNA was 72 nucleotides (nt) long, of which a 38-nt sequence was formed by double-stranded DNA with 19- and 15-nt single-stranded overhangs, respectively . Three open reading frames (ORFs), encoded by the 4,053-bp plasmid, were essential for the production of sdsDNA . These included an ORF with an unknown function, the retron reverse transcriptase, and an ORF encoding the cold shock protein homologue . This plasmid was also able to confer phage resistance onto the host cell by a mechanism which was independent of sdsDNA synthesis. J Bacteriol, 2001 May, 183(9), 2733 - 45 Roles of hilC and hilD in regulation of hilA expression in Salmonella enterica serovar Typhimurium; Lucas RL et al.; Sequences between -332 and -39 upstream of the hilA promoter are required for repression of hilA . An unidentified repressor is thought to bind these upstream repressing sequences (URS) to inhibit hilA expression . Two AraC-like transcriptional regulators encoded on Salmonella pathogenicity island 1 (SPI1), HilC and HilD, bind to the URS to counteract the repression of hilA . The URS is required for regulation of hilA by osmolarity, oxygen, PhoP/PhoQ, and SirA/BarA . Here, we show that FadD, FliZ, PhoB, and EnvZ/OmpR also require the URS to regulate hilA . These environmental and regulatory factors may affect hilA expression by altering the expression or activity of HilC, HilD, or the unknown repressor . To begin investigating these possibilities, we tested the effects of environmental and regulatory factors on hilC and hilD expression . We also examined hilA regulation when hilC or hilD was disrupted or expressed to a high level . Although hilC is regulated by all environmental conditions and regulatory factors that modulate hilA expression, hilC is not required for the regulation of hilA by any conditions or factors except EnvZ/OmpR . In contrast, hilD is absolutely required for hilA expression, but environmental conditions and regulatory factors have little or no effect on hilD expression . We speculate that EnvZ/OmpR regulates hilA by altering the expression and/or activity of hilC, while all other regulatory conditions and mutations regulate hilA by modulating hilD posttranscriptionally . We also discuss models in which the regulation of hilA expression is mediated by modulation of the expression or activity of one or more repressors. Infect Immun, 2001 May, 69(5), 3164 - 74 Disruption of the genes for ClpXP protease in Salmonella enterica serovar Typhimurium results in persistent infection in mice, and development of persistence requires endogenous gamma interferon and tumor necrosis factor alpha; Yamamoto T et al.; The enteric pathogen Salmonella enterica serovar Typhimurium, similar to other facultative intracellular pathogens, has been shown to respond to the hostile conditions inside macrophages of the host organism by producing a set of stress proteins that are also induced by various environmental stresses . The stress-induced ClpXP protease is a member of the ATP-dependent proteases, which are known to be responsible for more than 90% of all proteolysis in Escherichia coli . To investigate the contribution of the ClpXP protease to the virulence of serovar Typhimurium we initially cloned the clpP and clpX operon from the pathogenic strain serovar Typhimurium chi3306 and then created insertional mutations in the clpP and/or clpX gene . The Delta clpP and Delta clpX mutants were used to inoculate BALB/c mice by either the intraperitoneal or the oral route and found to be limited in their ability to colonize organs of the lymphatic system and to cause systemic disease in the host . A variety of experiments were performed to determine the possible reasons for the loss of virulence . An oxygen-dependent killing assay using hydrogen peroxide and paraquat (a superoxide anion generator) and a serum killing assay using murine serum demonstrated that all of the serovar Typhimurium Delta clpP and Delta clpX mutants were as resistant to these killing mechanisms as the wild-type strain . On the other hand, the macrophage survival assay revealed that all these mutants were more sensitive to the intracellular environment than the wild-type strain and were unable to grow or survive within peritoneal macrophages of BALB/c mice . In addition, it was revealed that the serovar Typhimurium ClpXP-depleted mutant was not completely cleared but found to persist at low levels within spleens and livers of mice . Interferon gamma-deficient mice and tumor necrosis factor alpha-deficient mice failed to survive the attenuated serovar Typhimurium infections, suggesting that both endogenous cytokines are essential for regulation of persistent infection with serovar Typhimurium. Infect Immun, 2001 May, 69(5), 3110 - 9 Stable transfection of the bovine NRAMP1 gene into murine RAW264.7 cells: effect on Brucella abortus survival; Barthel R et al.; Genetically based natural resistance to brucellosis in cattle provides for novel strategies to control zoonotic diseases . Bovine NRAMP1, the homologue of a murine gene (Bcg), has been identified as a major candidate for controlling the in vivo resistant phenotype . We developed an in vitro model for expression of resistance- and susceptibility-associated alleles of bovine NRAMP1 as stable transgenes under the regulatory control of the bovine NRAMP1 promoter in the murine RAW264.7 macrophage cell line (Bcg(s)) to analyze the regulation of the NRAMP1 gene and its role in macrophage function . We demonstrated that the 5'-flanking region of bovine NRAMP1, despite the lack of TATA and CAAT boxes, has a functional promoter capable of driving the expression of a transgene in murine macrophages . A polymorphism within a microsatellite in the 3' untranslated region critically affects the expression of bovine NRAMP1 and the control of in vitro replication of Brucella abortus but not Salmonella enterica serovar Dublin . We did not observe any differences in the production of NO by resting or gamma interferon (IFN-gamma)- and IFN-gamma-lipopolysaccharide (LPS)-treated transfected cell lines, yet the resistant transfected cell lines produced significantly less NO than other cell lines, following stimulation with LPS at 24 and 48 h. Infect Immun, 2001 May, 69(5), 3100 - 9 Antibodies against listerial protein 60 act as an opsonin for phagocytosis of Listeria monocytogenes by human dendritic cells; Kolb-Maurer A et al.; Human-monocyte-derived dendritic cells (MoDC) are very efficient in the uptake of Listeria monocytogenes, a gram-positive bacterium which is an important pathogen in humans and animals causing systemic infections with symptoms such as septicemia and meningitis . In this work, we analyzed the influence of blood plasma on the internalization of L . monocytogenes into human MoDC and compared the uptake of L . monocytogenes with that of Salmonella enterica serovar Typhimurium and Yersinia enterocolitica . While human plasma did not significantly influence the uptake of serovar Typhimurium and Y . enterocolitica by human MoDC, the efficiency of the uptake of L . monocytogenes by these phagocytes was strongly enhanced by human plasma . In plasma-free medium the internalization of L . monocytogenes was very low, whereas the addition of pooled human immunoglobulins resulted in the internalization of these bacteria to a degree comparable to the highly efficient uptake observed with human plasma . All human plasma tested contained antibodies against the 60-kDa extracellular protein of L . monocytogenes (p60), and anti-p60 antibodies were also found in the commercially available pooled immunoglobulins . Strikingly, in contrast to L . monocytogenes wild type, an iap deletion mutant (totally deficient in p60) showed only a minor difference in the uptake by human MoDC in the presence or the absence of human plasma . These results support the assumption that antibodies against the listerial p60 protein may play an important role in Fc-receptor-mediated uptake of L . monocytogenes by human MoDC via opsonization of the bacteria . This process may have a major impact in preventing systemic infection in L . monocytogenes in immunocompetent humans. Infect Immun, 2001 May, 69(5), 3092 - 9 Salmonella enterica serovar-host specificity does not correlate with the magnitude of intestinal invasion in sheep; Uzzau S et al.; The colonization of intestinal and systemic tissues by Salmonella enterica serovars with different host specificities was determined 7 days after inoculation of 1 to 2-month-old lambs . Following oral inoculation, S . enterica serovars Abortusovis, Dublin, and Gallinarum were recovered in comparable numbers from the intestinal mucosa, but serovar Gallinarum was recovered in lower numbers than the other serovars from systemic sites . The pattern of bacterial recovery from systemic sites following intravenous inoculation was similar . The magnitude of intestinal invasion was evaluated in ovine ligated ileal loops in vivo . Serovars Dublin and Gallinarum and the broad-host-range Salmonella serovar Typhimurium were recovered in comparable numbers from ileal mucosa 3 h after loop inoculation, whereas the recovery of serovar Abortusovis was approximately 10-fold lower . Microscopic analysis of intestinal mucosae infected with serovars Typhimurium and Dublin showed dramatic morphological changes and infiltration of inflammatory cells, whereas mucosae infected with serovars Abortusovis and Gallinarum were indistinguishable from uninfected mucosae . Together these data suggest that Salmonella serovar specificity in sheep correlates with bacterial persistence at systemic sites . Intestinal invasion and avoidance of the host's intestinal inflammatory response may contribute to but do not determine the specificity of serovar Abortosovis for sheep . Intestinal invasion by serovar Abortusovis was significantly reduced after mutation of invH but was not reduced following curing of the virulence plasmid, suggesting that the Salmonella pathogenicity island 1 influences but the virulence plasmid genes do not influence the ability of serovar Abortusovis to invade the intestinal mucosa in sheep. Infect Immun, 2001 May, 69(5), 3021 - 30 Flagellar phase variation of Salmonella enterica serovar Typhimurium contributes to virulence in the murine typhoid infection model but does not influence Salmonella-induced enteropathogenesis; Ikeda JS et al.; Although Salmonella enterica serovar Typhimurium can undergo phase variation to alternately express two different types of flagellin subunit proteins, FljB or FliC, no biological function for this phenomenon has been described . In this investigation, we constructed phase-locked derivatives of S . enterica serovar Typhimurium that expressed only FljB (termed locked-ON) or FliC (termed locked-OFF) . The role of phase variation in models of enteric and systemic pathogenesis was then evaluated . There were no differences between the wild-type parent strain and the two phase-locked derivatives in adherence and invasion of mouse epithelial cells in vitro, survival in mouse peritoneal macrophages, or in a bovine model of gastroenteritis . By contrast, the locked-OFF mutant was virulent in mice following oral or intravenous (i.v.) inoculation but the locked-ON mutant was attenuated . When these phase-locked mutants were compared in studies of i.v . kinetics in mice, similar numbers of the two strains were isolated from the blood and spleens of infected animals at 6 and 24 h . However, the locked-OFF mutant was recovered from the blood and spleens in significantly greater numbers than the locked-ON strain by day 2 of infection . By 5 days postinfection, a majority of the mice infected with the locked-OFF mutant had died compared with none of the mice infected with the locked-ON mutant . These results suggest that phase variation is not involved in the intestinal stage of infection but that once S . enterica serovar Typhimurium reaches the spleens of susceptible mice those organisms in the FliC phase can grow and/or survive better than t