Corynebacterium pseudotuberculosis biovar ovis: evaluación de la sensibilidad antibiótica in vitro / Corynebacterium pseudotuberculosis biovar ovis: Evaluation of antibiotics susceptibility in vitro

Resumen Los objetivos de este trabajo fueron estudiar la sensibilidad antibiótica de aislamientos de Corynebacterium pseudotuberculosis procedentes de pequeños rumiantes e investigar la presencia de integrones que contienen genes de resistencia. Se estudiaron 15 aislamientos de diferentes fuentes por los métodos de difusión y dilución. Por el método de difusión, amoxicilina-clavulánico, ampicilina, cefotaxima, cefoxitina, ciprofloxacina, cloranfenicol, eritromicina, estreptomicina, gentamicina, imipenem, kanamicina, norfloxacina, penicilina, rifampicina, tetraciclina, trimetroprima-sulfametoxazol y vancomicina fueron activos frente al 100% de los aislamientos, mientras que amicacina presentó resultados variables. En los aislamientos que desarrollaron frente a amicacina se investigó la presencia de integrones de clase 1. El resultado fue negativo, sugiriendo la ausencia del integrón. Utilizando el método de dilución, los antibióticos más activos correspondieron a los grupos de cefalosporinas, gluco-péptidos, macrólidos, quinolonas y tetraciclinas. Se demostró menor actividad de p-lactámicos y aminoglucósidos. No se registró variabilidad en los perfiles antibióticos en los aislamientos procedentes de diferentes fuentes.

Abstract The aims of this work were to study the antibiotic susceptibility in Corynebacterium pseudotuberculosis isolated from small ruminants and to determine the presence of integrons that contain resistance genes. Fifteen isolates of different sources were analysed using the diffusion and the dilution methods. When the diffusion method was performed, amoxicillin-clavulanic, ampicillin, cefotaxime, cefoxitin, ciprofloxacin, chloramphenicol, erythromycin, streptomycin, gentamicin, imipenem, kanamycin, norfloxacin, penicillin, rifampicin, tetracycline, trimethoprim-sulfamethoxazole and vancomycin were effective against the 100% of isolates, while amikacin showed variable results. The isolates that were able to grow with amikacin, were studied in relation to the presence of integron class 1. The result was negative, suggesting the absence of integron. Using dilution method, the antibiotics belonging to the cephalosporin, glycopeptide, macrolide, quinolone, and tetracycline groups were the most active ones for the C. pseudotuberculosis biovar ovis isolates. Less activity of p-lactam and aminoglycosides were observed. There was no observation of variability in the antibiotic patterns in the strains coming from different sources.

Sodium butyrate ameliorates Corynebacterium pseudotuberculosis infection in RAW264.7 macrophages and C57BL/6 mice.

Corynebacterium pseudotuberculosis (CP) infection in livestock has become highly difficult to control. To decrease the incidence of CP infection, the supplementation of feed with non-antibiotic antibacterial substances is a potential approach. The aim of this study was to assess the effects of sodium butyrate (NaB), a potential alternative to antibiotics, on CP infection in RAW264.7 macrophages and C57BL/6 mice. Our data showed that NaB (2 mM) significantly ameliorated CPinfection in RAW264.7 macrophages and decreased the bacterial load in the spleens of infected mice. By real-time PCR, we found that NaB induced significant decreases in zinc-dependent superoxide dismutase (sodC) and tip protein C (spaC) expression in CP from infected-RAW264.7 cells and in phospholipase D (pld) and spaC expression in CP from the spleens of infected mice. NaB treatment significantly up-regulated cathelicidin-related antimicrobial peptide (cramp) expression in spleens of mice infected with CP. Furthermore, NaB alleviated histopathological changes in spleens of CP-infected mice. In conclusion, NaB ameliorated CP infection in RAW264.7 macrophages and C57BL/6 mice, and these effects may be related to the modulation of sodC, spaC, pld, and cramp expression.

[Corynebacterium pseudotuberculosis biovar ovis: Evaluation of antibiotics susceptibility in vitro]. / Corynebacterium pseudotuberculosis biovar ovis: evaluación de la sensibilidad antibiótica in vitro.

The aims of this work were to study the antibiotic susceptibility in Corynebacterium pseudotuberculosis isolated from small ruminants and to determine the presence of integrons that contain resistance genes. Fifteen isolates of different sources were analysed using the diffusion and the dilution methods. When the diffusion method was performed, amoxicillin-clavulanic, ampicillin, cefotaxime, cefoxitin, ciprofloxacin, chloramphenicol, erythromycin, streptomycin, gentamicin, imipenem, kanamycin, norfloxacin, penicillin, rifampicin, tetracycline, trimethoprim-sulfamethoxazole and vancomycin were effective against the 100% of isolates, while amikacin showed variable results. The isolates that were able to grow with amikacin, were studied in relation to the presence of integron class1. The result was negative, suggesting the absence of integron. Using dilution method, the antibiotics belonging to the cephalosporin, glycopeptide, macrolide, quinolone, and tetracycline groups were the most active ones for the C.pseudotuberculosis biovar ovis isolates. Less activity of ß-lactam and aminoglycosides were observed. There was no observation of variability in the antibiotic patterns in the strains coming from different sources.

The polyanions heparin and suramin impede binding of free adenine to a DNA glycosylase from C. pseudotuberculosis.

Currently no effective treatment is available to combat infections caused by Corynebacterium pseudotuberculosis in livestock. Survival of this Gram-positive bacterium in rapidly-growing pathogens in hostile environments is strongly dependent on the existence of a robust DNA repair system to prevent DNA mutations and contribute to bacterial colonization and virulence. The adenine/guanine-specific DNA glycosylase (MutY) is evolutionarily conserved and has been well characterized due to its central role in the prevention of mutagenesis and DNA repair. The aim of this study was the characterization of the target protein interaction with free adenine, suramin, and heparin, as well as the binding competition characterization between the molecules. The dissociation constant for free adenine interaction with Corynebacterium pseudotuberculosis MutY (Cp-MutY) was determined, 86 ±â€¯2.5 µM. NMR competition experiments demonstrated, that the polyanions heparin and suramin compete with adenine for the protein active site. The determined dissociation constant for the heparin/Cp-MutY interaction was 5.9 ±â€¯1.0 µM and for suramin was 16 ±â€¯1.5 µM. Docking of both polyanions with Cp-MutY revealed a possible mode of interaction and indicates that these molecules can interfere with the protein interaction with damaged DNA or prevent the binding of the adenine base in the enzyme active site.

Sensibilidade in vitro a antimicrobianos de Corynebacterium pseudotuberculosis isolados de pequenos ruminantes da região Centro- Norte do Estado da Bahia / In vitro antimicrobial susceptibility of Corynebacterium pseudotuberculosis isolated from small ruminants from the North-Central region of the State of Bahia

Introdução: corynebacterium pseudotuberculosis é uma bactéria com importância em medicina veterinária por ser o agente etiológico da Linfadenite Caseosa (LC) em pequenos ruminantes. A doença leva a perdas econômicas devido a condenação de carcaças, diminuição de produtividade e redução do valor comercial do couro dos animais acometidos. O tratamento da doença é pouco eficaz, pois os agentes antimicrobianos não conseguem atravessar a barreira dos granulomas, mas tem sido proposta a inoculação intracapsular de antibióticos como tratamento e como medida de prevenção de contaminação ambiental. Objetivo: devido a esse fato, o presente estudo teve como objetivo avaliar a sensibilidade in vitro de isolados clínicos de Corynebacterium pseudotuberculosis isolados de animais da região Centro-Norte do estado da Bahia. Metodologia: foram retirados material de granulomas de 11 animais de uma fazenda na região acima mencionada, e as bactérias foram isoladas a partir desse material. Esses isolados então foram submetidos a metodologia de difusão em disco de ágar utilizando-se discos impregnados com doze antibióticos diferentes. Resultados: 90,9% (10/11) dos isolados foram resistentes a oxacilina. Com relação à sensibilidade, 100% dos isolados foram sensíveis a ampicilina, amicacina, amoxicilina, cefalotina, ceftriaxona, ciprofloxacina, enrofloxacina, neomicina e penicilina, enquanto 90,9% destes apresentaram sensibilidade a bactericina e doxiciclina. Conclusão: pode-se concluir que os isolados de C. pseudotuberculosis da região estudada apresentam sensibilidade a diversos antibióticos, o que pode facilitar na escolha de um antimicrobiano com menor toxicidade para fins de tratamento com inoculação intracapsular do medicamento.

Background: corynebacterium pseudotuberculosisis important bacteria in veterinary medicine because it is the Etiologic Agent of Caseous Lymphadenitis (CL) in small ruminants. The disease leads to economic losses due to condemnation of carcasses, productivity decrease and leather commercial value reduction of affected animals affected. The treatment of the disease is not very effective, because antimicrobial agents cannot cross the barrier of granulomas, but it has been proposed the intracapsular inoculation of antibiotics as treatment and as a measure of prevention of environmental contamination. Objective: due to this fact, the present study aimed to evaluate the in vitro susceptibility of clinical isolates of Corynebacterium pseudotuberculosis isolated from animals in the North Central region of the State of Bahia. Methodology: granuloma material were removed from 11 animals from a farm in the above mentioned area, and the bacteria were isolated from this material. These isolated bacteria were then subjected to disk diffusion method of agar using disks impregnated with twelve different antibiotics. Results: 90,9% (10/11) the isolated bacteria were resistant to oxacillin.With respect to sensitivity, 100% of the isolates bacteria were susceptible to amikacin, ampicillin, amoxicillin, cephalotin, ceftriaxone, ciprofloxacin, enrofloxacin, neomycin and penicillin, while 90.9% of these showed sensitivity to bacitracin and doxycycline. Conclusion: it can be concluded that the isolated bacteria of C. pseudotuberculosis from the region studied present sensitivity to different antibiotics, which can facilitate the choice of a less toxic antimicrobial for treating with intracapsular inoculation of the medicine.

Determination of Corynebacterium pseudotuberculosis prevalence and antimicrobial susceptibility pattern of isolates from lymph nodes of sheep and goats at an organic export abattoir, Modjo, Ethiopia.

UNLABELLED: Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis, a suppurative abscessation in the superficial and internal lymph nodes and internal organs of small ruminants. This study was conducted on the superficial lymph nodes and carcasses of 768 small ruminants slaughtered at a slaughterhouse during the study period; 82 had abscesses or caseous lymphadenitis. The most frequent sites of abscesses in goats were the prescapular (34, 5·54%) and prefemoral lymph nodes (24, 3·91%) respectively. Similar patterns were observed in sheep. The prevalence of caseous lymphadenitis was found to be significantly higher in adult than in young animals, in both species (P < 0·05). The age-wise prevalence rates of lesions on post-mortem inspection, at 95% CI, were 2·7% (2·3-3·1%) and 3·1% (2·8-3·4%) in young sheep and goats, respectively, and 24·4% (17·4-31·4%) and 27·5% (23·8-31·2%) in adult sheep and goats respectively. Corynebacterium pseudotuberculosis isolates were recovered from 72% (59/82) of animals found to have post-mortem evidence of abscesses. The Coryne. pseudotuberculosis isolates were susceptible to the antibiotics norfloxacin, tetracycline, doxycyline HCl and kanamycine; however, resistance was observed against ampicillin, clindamycin and doxycyline HCl. In conclusion, this study reported the magnitude of the problem in the country for the first time and the authors recommend a thorough investigation of wider study areas. SIGNIFICANCE AND IMPACT OF THE STUDY: This work presents data on the prevalence of caseous lymphadenitis in slaughtered sheep and goats as well as the isolation and antibiotic susceptibility pattern of Corynebacterium pseudotuberculosis for the first time in Ethiopia. The carcasses of small ruminants are the major livestock product exported from the country and serves as an important source of foreign currency. Assessing the impact of diseases such as caseous lymphadenitis in the industry would be of great significance. This work forms initial data that call for further wider investigations to gain complete understanding of its impact in the country.

An integrated structural proteomics approach along the druggable genome of Corynebacterium pseudotuberculosis species for putative druggable targets.

BACKGROUND: The bacterium Corynebacterium pseudotuberculosis (Cp) causes caseous lymphadenitis (CLA), mastitis, ulcerative lymphangitis, and oedema in a number of hosts, comprising ruminants, thereby intimidating economic and dairy industries worldwide. So far there is no effective drug or vaccine available against Cp. Previously, a pan-genomic analysis was performed for both biovar equi and biovar ovis and a Pathogenicity Islands (PAIS) analysis within the strains highlighted a large set of proteins that could be relevant therapeutic targets for controlling the onset of CLA. In the present work, a structural druggability analysis pipeline was accomplished along 15 previously sequenced Cp strains from both biovar equi and biovar ovis. METHODS AND RESULTS: We computed the whole modelome of a reference strain Cp1002 (NCBI Accession: NC_017300.1) and then the homology models of proteins, of 14 different Cp strains, with high identity (≥ 85%) to the reference strain were also done. Druggability score of all proteins pockets was calculated and only those targets that have a highly druggable (HD) pocket in all strains were kept, a set of 58 proteins. Finally, this information was merged with the previous PAIS analysis giving two possible highly relevant targets to conduct drug discovery projects. Also, off-targeting information against host organisms, including Homo sapiens and a further analysis for protein essentiality provided a final set of 31 druggable, essential and non-host homologous targets, tabulated in table S4, additional file 1. Out of 31 globally druggable targets, 9 targets have already been reported in other pathogenic microorganisms, 3 of them (3-isopropylmalate dehydratase small subunit, 50S ribosomal protein L30, Chromosomal replication initiator protein DnaA) in C. pseudotuberculosis. CONCLUSION: Overall we provide valuable information of possible targets against C. pseudotuberculosis where some of these targets have already been reported in other microorganisms for drug discovery projects, also discarding targets that might be physiologically relevant but are not amenable for drug binding. We propose that the constructed in silico dataset might serve as a guidance for the scientific community to have a better understanding while selecting putative therapeutic protein candidates as druggable ones as effective measures against C. pseudotuberculosis.

Minimum inhibitory concentrations of equine Corynebacterium pseudotuberculosis isolates (1996-2012).

BACKGROUND: Few studies report the minimum inhibitory concentrations for antimicrobials against equine Corynebacterium pseudotuberculosis isolates. HYPOTHESIS/OBJECTIVES: To evaluate trends in the in vitro activities of 20 antimicrobials against equine Corynebacterium pseudotuberculosis isolates from 1996 to 2012 and to determine if a relationship exists between the minimum inhibitory concentration (MIC) and location of the abscess. ANIMALS: Corynebacterium pseudotuberculosis isolates from 196 horses with naturally occurring disease. METHODS: Retrospective and cross-sectional design. Medical records were reviewed to obtain clinical and MIC data. Minimum inhibitory concentrations were determined by the microdilution technique. The MIC results over 3 periods were compared (1996-2001, 2002-2006, 2007-2012). RESULTS: The MIC90 values for clinically relevant antimicrobials were as follows: chloramphenicol ≤ 4 µg/mL, enrofloxacin ≤ 0.25 µg/mL, gentamicin ≤ 1 µg/mL, penicillin =0.25 µg/mL, rifampin ≤ 1 µg/mL, tetracycline ≤ 2 µg/mL, trimethoprim-sulfamethoxazole (TMS) ≤ 0.5 µg/mL, ceftiofur =2 µg/mL, and doxycycline ≤ 2 µg/mL. There were no significant changes in MIC results over the study period. There was no relationship between MIC patterns and abscess location. CONCLUSIONS AND CLINICAL IMPORTANCE: The MIC50 and MIC90 values of antimicrobials evaluated in this study for equine isolates of C. pseudotuberculosis did not vary over time. Abscess location was not associated with different MIC patterns in cultured isolates. Several commonly used antimicrobials are active in vitro against C. pseudotuberculosis in vitro.

Label-free proteomic analysis to confirm the predicted proteome of Corynebacterium pseudotuberculosis under nitrosative stress mediated by nitric oxide.

BACKGROUND: Corynebacterium pseudotuberculosis biovar ovis is a facultative intracellular pathogen, and the etiological agent of caseous lymphadenitis in small ruminants. During the infection process, the bacterium is subjected to several stress conditions, including nitrosative stress, which is caused by nitric oxide (NO). In silico analysis of the genome of C. pseudotuberculosis ovis 1002 predicted several genes that could influence the resistance of this pathogen to nitrosative stress. Here, we applied high-throughput proteomics using high definition mass spectrometry to characterize the functional genome of C. pseudotuberculosis ovis 1002 in the presence of NO-donor Diethylenetriamine/nitric oxide adduct (DETA/NO), with the aim of identifying proteins involved in nitrosative stress resistance. RESULTS: We characterized 835 proteins, representing approximately 41% of the predicted proteome of C. pseudotuberculosis ovis 1002, following exposure to nitrosative stress. In total, 102 proteins were exclusive to the proteome of DETA/NO-induced cells, and a further 58 proteins were differentially regulated between the DETA/NO and control conditions. An interactomic analysis of the differential proteome of C. pseudotuberculosis in response to nitrosative stress was also performed. Our proteomic data set suggested the activation of both a general stress response and a specific nitrosative stress response, as well as changes in proteins involved in cellular metabolism, detoxification, transcriptional regulation, and DNA synthesis and repair. CONCLUSIONS: Our proteomic analysis validated previously-determined in silico data for C. pseudotuberculosis ovis 1002. In addition, proteomic screening performed in the presence of NO enabled the identification of a set of factors that can influence the resistance and survival of C. pseudotuberculosis during exposure to nitrosative stress.

First report of Corynebacterium pseudotuberculosis from caseous lymphadenitis lesions in Black Alentejano pig (Sus scrofa domesticus).

BACKGROUND: Corynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis, a common disease in small ruminant populations throughout the world and responsible for a significant economic impact for producers. CASE PRESENTATION: To our knowledge, this is the first characterization of C. pseudotuberculosis from caseous lymphadenitis lesions in Black Alentejano pig (Sus scrofa domesticus). In this study, phenotypic and genotypic identification methods allocated the swine isolates in C. pseudotuberculosis biovar ovis. The vast majority of the isolates were able to produce phospholipase D and were susceptible to most of the antimicrobial compounds tested. Macrorestriction patterns obtained by Pulsed Field Gel Electrophoresis (PFGE) grouped the C. pseudotuberculosis in two clusters with a high similarity index, which reveals their clonal relatedness. Furthermore, swine isolates were compared with C. pseudotuberculosis from caprines and PFGE patterns also showed high similarity, suggesting the prevalence of dominant clones and a potential cross-dissemination between these two animal hosts. CONCLUSIONS: This work represents the first report of Corynebacterium pseudotuberculosis from caseous lymphadenitis lesions in Black Alentejano pig and alerts for the importance of the establishment of suitable control and sanitary management practices to control the infection and avoid further dissemination of this important pathogen to other animal hosts.

In vitro susceptibility of equine-obtained isolates of Corynebacterium pseudotuberculosis to gallium maltolate and 20 other antimicrobial agents.

This study's objective was to determine the in vitro antimicrobial activities of gallium maltolate (GaM) and 20 other antimicrobial agents against clinical equine isolates of Corynebacterium pseudotuberculosis. The growth of cultured isolates was not inhibited by any concentration of GaM. MIC data revealed susceptibility to commonly used antimicrobials.

Proteome scale comparative modeling for conserved drug and vaccine targets identification in Corynebacterium pseudotuberculosis.

Corynebacterium pseudotuberculosis (Cp) is a pathogenic bacterium that causes caseous lymphadenitis (CLA), ulcerative lymphangitis, mastitis, and edematous to a broad spectrum of hosts, including ruminants, thereby threatening economic and dairy industries worldwide. Currently there is no effective drug or vaccine available against Cp. To identify new targets, we adopted a novel integrative strategy, which began with the prediction of the modelome (tridimensional protein structures for the proteome of an organism, generated through comparative modeling) for 15 previously sequenced C. pseudotuberculosis strains. This pan-modelomics approach identified a set of 331 conserved proteins having 95-100% intra-species sequence similarity. Next, we combined subtractive proteomics and modelomics to reveal a set of 10 Cp proteins, which may be essential for the bacteria. Of these, 4 proteins (tcsR, mtrA, nrdI, and ispH) were essential and non-host homologs (considering man, horse, cow and sheep as hosts) and satisfied all criteria of being putative targets. Additionally, we subjected these 4 proteins to virtual screening of a drug-like compound library. In all cases, molecules predicted to form favorable interactions and which showed high complementarity to the target were found among the top ranking compounds. The remaining 6 essential proteins (adk, gapA, glyA, fumC, gnd, and aspA) have homologs in the host proteomes. Their active site cavities were compared to the respective cavities in host proteins. We propose that some of these proteins can be selectively targeted using structure-based drug design approaches (SBDD). Our results facilitate the selection of C. pseudotuberculosis putative proteins for developing broad-spectrum novel drugs and vaccines. A few of the targets identified here have been validated in other microorganisms, suggesting that our modelome strategy is effective and can also be applicable to other pathogens.

Caprine abscess model of tulathromycin concentrations in interstitial fluid from tissue chambers inoculated with Corynebacterium pseudotuberculosis following subcutaneous or intrachamber administration.

Corynebacterium pseudotuberculosis causes chronic, suppurative, abscessing conditions in livestock and humans. We used an in vivo model to evaluate antimicrobial efficacy for focal abscesses caused by C. pseudotuberculosis. Tissue chambers were surgically implanted in the subcutaneous tissues of the right and left paralumbar fossa of 12 goats to serve as a model for isolated, focal abscesses. For each goat, one tissue chamber was inoculated with C. pseudotuberculosis, while the contralateral chamber served as an uninoculated control. Six goats were administered a single dose of tulathromycin at 2.5 mg/kg of body weight subcutaneously, while the other six received the same dose by injection directly into the inoculated chambers. Our objective was to compare the effects and tulathromycin concentrations in interstitial fluid (IF) samples collected from C. pseudotuberculosis-infected and control chambers following subcutaneous or intrachamber injection of tulathromycin. In addition, the effects of tulathromycin on the quantity of C. pseudotuberculosis reisolated from inoculated chambers were assessed over time. Tulathromycin IF concentrations from C. pseudotuberculosis-infected and control tissue chambers were similar to those in plasma following subcutaneous administration. Following intrachamber administration, tulathromycin IF concentrations in infected chambers were continuously above the MIC for the C. pseudotuberculosis isolate for 15 days. There were no significant differences for plasma area under the curve and elimination half-lives between subcutaneous and intrachamber administration. Six of the 12 infected chambers had no growth of C. pseudotuberculosis 15 days postadministration. Results of this study indicate that tulathromycin may be beneficial in the treatment of focal infections such as those caused by C. pseudotuberculosis.

A novel comparative genomics analysis for common drug and vaccine targets in Corynebacterium pseudotuberculosis and other CMN group of human pathogens.

Caseous lymphadenitis is a chronic goat and sheep disease caused by Corynebacterium pseudotuberculosis (Cp) that accounts for a huge economic loss worldwide. Proper vaccination or medication is not available because of the lack of understanding of molecular biology of the pathogen. In a recent approach, four Cp (CpFrc41, Cp1002, CpC231, and CpI-19) genomes were sequenced to elucidate the molecular pathology of the bacteria. In this study, using these four genome sequences along with other eight genomes (total 12 genomes) and a novel subtractive genomics approach (first time ever applied to a veterinary pathogen), we identified potential conserved common drug and vaccine targets of these four Cp strains along with other Corybacterium, Mycobacterium and Nocardia (CMN) group of human pathogens (Corynebacterium diphtheriae and Mycobacterium tuberculosis) considering goat, sheep, bovine, horse, and human as the most affected hosts. The minimal genome of Cp1002 was found to consist of 724 genes, and 20 conserved common targets (to all Cp strains as well as CMN group of pathogens) from various metabolic pathways (13 from host-pathogen common and seven from pathogen's unique pathways) are potential targets irrespective of all hosts considered. ubiA from host-pathogen common pathway and an ABC-like transporter from unique pathways may serve dual (drug and vaccine) targets. Two Corynebacterium-specific (mscL and resB) and one broad-spectrum (rpmB) novel targets were also identified. Strain-specific targets are also discussed. Six important targets were subjected to virtual screening, and one compound was found to be potent enough to render two targets (cdc and nrdL). We are currently validating all identified targets and lead compounds.

Molecular genotyping of multinational ovine and caprine Corynebacterium pseudotuberculosis isolates using pulsed-field gel electrophoresis.

Caseous lymphadenitis (CLA) is a chronic, suppurative disease, with a worldwide distribution, caused by Corynebacterium pseudotuberculosis. The clinical manifestation of CLA is known to vary between different countries, and has been postulated to be due to differences in the strains present in these countries. Forty-two sheep and goat isolates of C. pseudotuberculosis from Australia, Canada, Eire, The Netherlands and Northern Ireland were characterized by pulsed-field gel electrophoresis (PFGE), biotyping, antimicrobial susceptibility, and production of phospholipase D. The PFGE-determined genotypes of this multicentric collection were then compared with representative ovine and caprine isolates from a previously published panel of PFGE profiles of United Kingdom isolates. Digestion with SfiI generated 16-18 bands in the 48.5 and 290 kb range, and differentiated four distinct pulsotypes amongst the 36 ovine and 6 caprine strains which displayed remarkable homogeneity. Based on these results, it would appear that the genome of C. pseudotuberculosis is highly conserved, irrespective of the country of strain origin.

Systemic dexamethasone and its effect on normal aerobic bacterial flora of cow.

This study was carried out on 17 Holestein, heifers, aged between 1 to 2 years for determining the normal aerobic bacterial flora and their changes after dexamethasone injection. Swab samples were taken from eye, ear, pharynx and vagina before and 5 days after twice dexamethasone treatment. Results indicated that Bacillus cereus and Corynebacterium pseudotuberculosis had higher frequency of isolations than the other bacterial flora in eye, ear and pharynx. Actinomyces pyogenes was isolated with considerable frequency from vagina. Klebsiella pneumoniae was also isolated from pharynx and its frequency was increased significantly after dexamethasone injection (p < 0.05).

Comparative molecular characterization of Corynebacterium pseudotuberculosis of different origin.

Ribotyping and susceptibility to 17 antimicrobial agents were used to compare 37 isolates of Corynebacterium pseudotuberculosis (28 from horses, 1 from cattle, 3 from sheep and 5 from goats) derived from various types of lesions, and different geographic locations. According to the presence of nitrate reductase, all but one isolate from horses reduced nitrate (nitrate-positive), whereas all isolates from sheep and goats were unable to reduce nitrate (nitrate-negative). The ribotype of the nitrate-negative isolate from a horse with ulcerative lymphangitis was identical to all the other isolates from horses, and different than the ribotype of nitrate-negative isolates from sheep and goats. Ribotyping with one of the restriction endonucleases, Apa 1, revealed differences between, but not within, the two biotypes. However, ribotyping with Pst 1 endonuclease revealed one variant within the equine biotype and one variant within the ovine biotype. The minimum inhibitory concentration (MIC; microgram/ml) of antimicrobial agents against isolates from nitrate-negative and nitrate-positive groups was very similar, with the exception of isolates from sheep and goats which had a higher MIC for amikacin than isolates from horses and cattle.

Determinaçäo das condiçöes ótimas para detecçäo de anticorpos contra coynebacterium pseudotuberculosis através de método imunoenzimático (ELISA) / Enzyme linked immunosorbent assay (ELISA): optimal conditions for detection of antibodies produced against corinebacterium pseudotuberculosis

Resumo: O ensaio imunoenzimático (ELISA) foi utilizado para mensurar os níveis de anticorpos contra a exotoxina, linfadenina e os antigenos solúveis extraídos por SDS e por ultr-som do Corynebacterium pseudotuberculosis, nos soros de caprinos normais e naturalmente infectados. Nossos resultados indicam a exotoxina e a linfadenina como os melhores antigenos, dentre os estudados, para detectar anticorpos específicos contra o Corynebacterium pseudotuberculosis (au)