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 I, revealed differences between, but not within, the two biotypes. However, ribotyping with Pst I endonuclease revealed one variant within the equine biotype and one variant within the ovine biotype. The minimum inhibitory concentration (MIC; μg/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.     

Use of a real-time polymerase chain reaction-based fluorogenic 5' nuclease assay to evaluate insect vectors of Corynebacterium pseudotuberculosis infections in horses

OBJECTIVE: To develop and use a sensitive molecular assay for detecting the phospholipase D (PLD) exotoxin gene of Corynebacterium pseudotuberculosis in an attempt to identify insect vectors that may be important in transmission of clinical disease in horses. SAMPLE POPULATION: 2,621 flies of various species. PROCEDURE: A real-time polymerase chain reaction (PCR)-based fluorogenic 5' nuclease (TaqMan) system (ie, TaqMan PCR assay) was developed for the detection of the PLD gene in insects. Flies were collected monthly (May to November 2002) from 5 farms in northern California where C. pseudotuberculosis infection in horses is endemic. Three of the 5 farms (which housed a total of 358 horses) had diseased horses during the study period. A total of 2,621 flies of various species were tested for the PLD gene of C. pseudotuberculosis. RESULTS: Evidence of bacterial DNA for the PLD gene was detected in skin biopsy specimens from clinically affected horses and from 3 fly species collected from farms where affected horses were housed. Farms with a high incidence of diseased horses had a high proportion of insects carrying the organism. High percentages of flies with positive results for the PLD gene were observed in October, when most clinically affected horses were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Our results are consistent with the hypothesis that C. pseudotuberculosis may be vectored to horses by flies. Three potential vectors were identified, including Haematobia irritans, Stomoxys calcitrans, and Musca domestica. The organism can be identified in up to 20% of house flies (Musca domestica) in the vicinity of diseased horses.     

Molecular epidemiology of Types I/III strains of Mycobacterium avium subspecies paratuberculosis isolated from goats and cattle

Molecular characterization of Mycobacterium avium subsp. paratuberculosis (M. a. paratuberculosis) isolates classifies them into three groups: cattle or Type II, sheep or Type I, and intermediate or Type III. To avoid problems associated with characterization of extremely slow growth strains, PCR-based techniques that divide the M. a. paratuberculosis strains in two main groups (cattle or Type II, and sheep or Types I/III) can be performed. The objectives of this study were to characterize the M. a. paratuberculosis isolates identified by different PCR-based tests (IS1311-PCR and restriction endonuclease analysis, PCR test based on a DNA sequence difference, and a PCR aimed at three Type I-specific loci), and to determine the clinical and epidemiological implications of Types I/III M. a. paratuberculosis strains in livestock. One hundred and fifty-eight M. a. paratuberculosis strains from domestic ruminants were analyzed. One hundred and six M. a. paratuberculosis isolates (61 from goats and 45 from cattle) were classified as Type II strains; and 52 (29 from cows, 20 from goats, and three from sheep) were included in the Types I/III. The Types I/III M. a. paratuberculosis strains were associated to Spanish native breeds. The majority of these animals had not been in direct or indirect contact with sheep flocks infected with M. a. paratuberculosis. This fact should be taken into account when implementing paratuberculosis control programs.     

Molecular characterization of Corynebacterium pseudotuberculosis isolates using ERIC-PCR

Caseous lymphadenitis is an infectious sheep and goats disease caused by Corynebacterium pseudotuberculosis and characterized by abscesses in superficial and visceral lymph nodes. C. pseudotuberculosis strains isolated from these hosts have been shown to be very difficult to type by the existing methods. The aim of this study is evaluating the potential of the Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR) as a tool for molecular typing of C. pseudotuberculosis strains isolated in sheep. One hundred and twenty seven isolates of C. pseudotuberculosis were isolated from lesions suspected to have had caseous lymphadenitis collected from sheep at the slaughterhouse. Animals were from 24 flocks in 13 municipalities of the Minas Gerais State, Brazil. Species identification of the isolates was performed by routine biochemical tests and mPCR. Fingerprint was performed by RAPD using ERIC-1R, ERIC-2 and ERIC-1R+ERIC-2 primers. Seventeen different genotypes were generated by ERIC 1-PCR, 21 genotypes by ERIC 2-PCR and 21 genotypes by ERIC 1+2-PCR. Hunter-Gaston Discrimination Index (HGDI) found for ERIC 1, ERIC 2, ERIC 1+2 PCR were 0.69, 0.87, and 0.84, respectively. For most herds evaluated observed at most three different genotypes among isolates from animals of these property, in all ERIC-PCR assays. However a few flocks observed between four and nine genotypes per flock. The W Kendall value found for correlation among the three techniques of ERIC-PCR was 0.91 (P<5.0 x 10(-6)). The results show that ERIC-PCR has good discriminatory power and advantages over other DNA-based typing methods, making it a useful tool to discriminate C. pseudotuberculosis isolates.     

Host associated polymorphisms in the Corynebacterium pseudotuberculosis rpoB gene sequence

Corynebacterium pseudotuberculosis is a widespread facultative intracellular pathogen that causes caseous lymphadenitis disease in sheep and goats, and generates cutaneous abscesses and granulomas in horses and cattle. Although some genes have been studied for diagnostic and phylogenetic analysis within the genus Corynebacterium, at subspecies level the pathogen has been poorly analyzed. The aim of this study was to characterize C. pseudotuberculosis strains isolated from domestic animals, through the sequencing of a hypervariable rpoB gene segment. As result, there were identified host associated rpoB polymorphisms in strains infecting sheep, goats and horses from Chile. These differences suggest the existence of bacterial genotypes, in which the nucleotide similarity values were ranging from 98.8 to 99.8%. In conclusion, the analysis of polymorphisms in the partial rpoB sequence can be used as a diagnostic tool that differentiates C. pseudotuberculosis strains at subspecies level.     

A simple random amplified polymorphic DNA genotyping method for field isolates of Dermatophilus congolensis

Dermatophilus congolensis is the pathogenic actinomycete that causes dermatophilosis in cattle, lumpy wool in sheep and rain scald in horses. Phenotypic variation between isolates has previously been described, but its genetic basis, extent and importance have not been investigated. Standard DNA extraction methods are not always successful for D. congolensis due to its complex life cycle, one stage of which is encapsulated. Here we describe the development of rapid and reliable DNA extraction and random amplified polymorphic DNA (RAPD) methods that can be used for genotyping D. congolensis field isolates. Our results suggest that genotypic variation between isolates correlates with host species. Several DNA extraction methods and RAPD protocols were compared. An extraction method based on incubation of the bacterium in lysozyme, sodium dodecyl sulphate (SDS) and proteinase K treatments and phenolic extraction yielded high-quality DNA, which was used to optimize RAPD-polymerase chain reaction (PCR) protocols for two random primers. An alternative rapid, non-phenolic extraction method based on proteinase K treatment and thermal shock was selected for routine RAPD typing of isolates. DNA extracted from reference strains from cattle, sheep and horse using either method gave reproducible banding patterns with different DNA batches and different thermal cyclers. The rapid DNA extraction method and RAPD-PCR were applied to 38 D. congolensis field isolates. The band patterns of the field and type isolates correlated with host species but not with geographical location.     

Antimicrobial activity of cathelicidins BMAP28, SMAP28, SMAP29, and PMAP23 against Pasteurella multocida is more broad-spectrum than host species specific

The antimicrobial activity of linear, cationic alpha-helical peptides from cattle (BMAP28), sheep (SMAP28 and SMAP29), and pigs (PMAP23) were assessed to determine if activity was selective for Pasteurella multocida from a particular animal species or broad-spectrum against all P. multocida tested. The antimicrobial activities of synthetic peptides were determined for P. multocida isolated from cattle (10 isolates), sheep (10 isolates), and pigs (10 isolates) in a broth microdilution assay. All thirty isolates of P. multocida were susceptible to BMAP28 (MICs and MBCs, 1.0-1.9 microM); SMAP28 and SMAP29 (MICs and MBCs, 0.2-0.7 microM); and PMAP23 (MICs and MBCs, 4.3 to > or = 6.8 microM). Overall, the results of this study suggest that synthesized cathelicidins from cattle, sheep, and pigs had broad-spectrum antimicrobial activity against all P. multocida.     

Detection and Analysis of Shiga Toxin-producing Escherichia coli Isolates from Cattle and Sheep Sources in Some Regions of Xinjiang,China

Shiga toxin-producing Escherichia coli(STEC) is a new class of highly pathogenic food-borne pathogens carrying a prephage encoding one or two Shiga toxin genes. It has become an important public health issue that threatens human health. The present work aimed to characterize STEC strains isolated from cattle and sheep at various stages, in parts of Xinjiang, in terms of the presence of prevalence, genetic diversity, and antimicrobial susceptibility to 17 common antibiotics. Through amplification of four virulence genes (stx1, stx2, eae, hlyA)by PCR and ERIC-PCR genotyping to detection STEC isolates. In the present study, a total of 64 STEC strains were isolated from 431 samples from slaughterhouses, farms and markets. Of these, 31 (48.4%) of the isolates harbored stx1 + stx2, and only 29 (45.3%) of the isolates possessed stx1, only 4 (6.3%) of the isolates harbored stx2, and 1 isolates harbored all the 4 virulence genes. Drug sensitivity tests found that STEC strains displayed 7 antimicrobial resistance to midecamycin(61%), cephalothin(4.7%), cefoxitin(4.7%), ampicillin(3.1%), piperacillin(1.6%), tobramycin(1.6%), cefazolin(1.6%). The ERIC-PCR results showed a polymorphic distribution, which was divided into two clusters of A (36 strains) and B (28 strains). STEC strains isolated from cattle and sheep at various stages, in parts of Xinjiang, some of which might have the potential to cause food contamination and human diseases.     

新疆部分地区牛羊源产志贺毒素大肠埃希菌菌株检测与分析

产志贺毒素大肠埃希菌（Shiga toxin-producing Escherichia coli，STEC）是一类携带了前噬菌体编码的一种或两种志贺毒素基因的新发高致病性食源性病原菌，已成为威胁人类健康的重要公共卫生问题。为了解新疆部分地区牛、羊源各个环节产志贺毒素大肠埃希菌的感染情况及其遗传多样性，以及分离株对17种常见抗生素的敏感性，笔者采用PCR方法对STEC分离株进行了4种毒力基因（stx1、stx2、eae、hlyA）的检测和ERIC-PCR基因分型研究。结果表明：从屠宰场、养殖场和市场共431份样品中分离出产志贺毒素的大肠埃希菌64株，其中，编码stx1+stx2的STEC有31株（48.4%），只编码stx1的STEC有29株（45.3%），只编码stx2的STEC有4株（6.3%），4种毒力基因同时存在的有1株。药物敏感性检测发现STEC菌株对麦迪霉素（61%）、头孢噻吩（4.7%）、头孢西丁（4.7%）、氨苄西林（3.1%）、哌拉西林（1.6%）、妥布霉素（1.6%）、头孢唑啉（1.6%）等7种抗生素存在耐药。ERIC-PCR检测结果呈多态性分布，分为A（36株）和B（28株）两个簇。STEC菌株在新疆部分地区牛、羊源各个环节被检出，其中一些菌株可能会增加对食物的污染，从而引起人发病。     

The prevalence of Shiga toxin-producing Escherichia coli in cattle and sheep in the lower North Island, New Zealand

AIM: To genotype Escherichia coli cultured from the faeces of healthy cattle and sheep in the lower North Island, in order to investigate the possible role of ruminants as a reservoir for Shiga toxin-producing E. coli (STEC) in New Zealand. METHODS: A total of 952 strains of E. coli were isolated on selective media, from faecal swabs from 319 animals (187 cattle and 132 sheep) from four sites in the Manawatu and Rangitikei regions of New Zealand. A multiplex polymerase chain reaction (PCR) was used to genotype the E. coli isolates, using amplification of Shiga toxin genes (stx1 and stx2) and the E. coli attaching and effacing gene (eae). RESULTS: Isolates of E. coli were cultured from swabs from 178/187 (95.2%) cattle and all 132 (100%) sheep. Ninety-nine (10.4%) of the isolates were stx1 only, 83 (8.7%) stx2 only, 33 (3.5%) stx1 and stx2, 23 (2.4%) stx1 and eae, one (0.1%) stx2 and eae, and 115 (12.1%) were eae only. Overall, 51 (27.3%) cattle and 87 (65.9%) sheep were stx-positive, whereas 69 (36.9%) cattle and 36 (27.3%) sheep were eae-positive. CONCLUSIONS: Both healthy cattle and sheep are asymptomatic reservoirs of STEC in New Zealand. Direct contact with cattle and sheep or consumption of water or foodstuffs contaminated with cattle of sheep faeces may represent a significant source of infection for humans.     

Enterocolitis in cattle associated with Yersinia pseudotuberculosis infection

A syndrome in cattle of diarrhoea and death associated with enteric Yersinia pseudotuberculosis infection is described. Outbreaks occurred during winter and early spring in adult cattle grazing pastures waterlogged by recent flooding or persistent heavy rain. Antibiotic therapy was effective early in the course of the syndrome. At necropsy there was severe acute enterocolitis, and bacteria consistent with Y. pseudotuberculosis were observed in the lesions. This organism could usually be isolated from the intestines of affected animals but was recovered less often from other organs. Representative isolates were identified as Y. pseudotuberculosis serotype III. The association of this syndrome with waterlogged pastures and low temperatures suggests that these conditions favour transmission of Y. pseudotuberculosis infection in cattle. The role of Y. pseudotuberculosis as primary pathogen requires confirmation.     

Enteritis in sheep, goats and pigs due to Yersinia pseudotuberculosis infection

The features of naturally occurring Yersinia pseudotuberculosis serotype III infections in 16 sheep, one goat and 3 pigs, and Y. pseudotuberculosis serotype I infections in 3 goats, are described. Affected animals usually had diarrhoea and were in poor condition or emaciated. A number were moribund or dead when submitted for necropsy. Thickening of the caecal and colonic mucosa was the only gross lesion attributable to Y. pseudotuberculosis infection, with liver or other visceral abscesses not being seen. Characteristic microabscesses were demonstrated in the intestinal mucosa of 10 sheep, one goat and one pig infected with Y. pseudotuberculosis serotype III and one goat infected with Y. pseudotuberculosis serotype I. Sheep, goats and pigs dosed orally with Y. pseudotuberculosis serotype III, the serotype isolated most commonly from these species, developed intestinal infection. In sheep and pigs, infection was accompanied by diarrhoea. Haematological changes and specific antibodies were elicited in all 3 species in response to infection. Microabscesses were seen in the intestinal mucosa of all experimentally exposed animals. The occurrence of field cases and the results of experimental exposure confirm that Y. pseudotuberculosis serotype III is an enteropathogen of sheep, goats and pigs. The association of Y. pseudotuberculosis serotype I with lesions in a goat, indicates that this bacterium may also be a pathogen of this species. It is concluded that Y. pseudotuberculosis serotype III is an enteric pathogen of a wide range of ungulate species including cattle, buffalo, deer, antelopes, sheep, goats and pigs. Serotypes I and II, while having a more restricted host range, are probably also pathogens of ungulates and, in particular, deer, antelopes and goats.     

Isolation and characterization of Treponema phagedenis-like spirochetes from digital dermatitis lesions in Swedish dairy cattle

Background

Digital dermatitis in cattle is an emerging infectious disease. Ulcerative lesions are typically located on the plantar skin between the heel bulbs and adjacent to the coronet. Spirochetes of the genus Treponema are found in high numbers in the lesions and are likely to be involved in the pathogenesis. The aim of this study was to obtain pure cultures of spirochetes from cattle with digital dermatitis and to describe them further.

Methods

Tissue samples and swabs from active digital dermatitis lesions were used for culturing. Pure isolates were subjected to, molecular typing through 16S rRNA gene sequencing, pulsed-field gel electrophoresis (PFGE), random amplified polymorphic DNA (RAPD) and an intergenic spacer PCR developed for Treponema spp. as well as API-ZYM and antimicrobial susceptibility tests. The antimicrobial agents used were tiamulin, valnemulin, tylosin, aivlosin, lincomycin and doxycycline.

Results

Seven spirochete isolates from five herds were obtained. Both 16S rRNA gene sequences, which were identical except for three polymorphic nucleotide positions, and the intergenic spacer PCR indicated that all isolates were of one yet unnamed species, most closely related to Treponema phagedenis. The enzymatic profile and antimicrobial susceptibility pattern were also similar for all isolates. However it was possible to separate the isolates through their PFGE and RAPD banding pattern.

Conclusion

This is the first report on isolation of a Treponema sp. from cattle with digital dermatitis in Scandinavia. The phylotype isolated has previously been cultured from samples from cattle in the USA and the UK and is closely related to T. phagedenis. While very similar, the isolates in this study were possible to differentiate through PFGE and RAPD indicating that these methods are suitable for subtyping of this phylotype. No antimicrobial resistance could be detected among the tested isolates.     

Prevalence of methicillin-resistant Staphylococci on a farm: staff can harbour MRS when animals do not

The aim of this work was to establish the prevalence of methicillin-resistant Staphylococci (MRS) in the animals and staff of a teaching and research farm. Samples of dairy cattle (36), beef cattle (26), sheep (19), horses (21), pigs (23), goats (23) and humans (13) were collected and screened for the presence of MRS. The detection of mecA gene was performed by PCR to determine the resistance of the samples to methicillin. Antimicrobial-resistance testing to penicillin, meropenem, ceftriaxone, cephalothin, oxacillin, levofloxacin, enrofloxacin, chloramphenicol, ciprofloxacin, gentamicin, clindamycin, erytromycin, linezolid, sulfamethoxazole/trimethoprim, tetracycline, doxycycline and vancomycin was performed on the mecA+ isolates. From the 161 samples, four methicillin-resistant coagulase-negative Staphylococci (MRCoNS) were isolated from human beings (31%), whereas none was isolated from animals (0%). No methicillin-resistant Staphylococcus aureus (MRSA) were isolated. All of the MRCoNS isolates from this work presented different antimicrobial resistance patterns. MRCoNS may be present in humans associated with animals while not present in the animals. Selective pressure outside of the farm and a lack of MRCoNS transmission between humans and animals may be responsible for this lack of correlation.     

Effect of the interval between shearing and dipping on the spread of Corynebacterium pseudotuberculosis infection in sheep

OBJECTIVE: To determine whether the spread of Corynebacterium pseudotuberculosis infection to sheep in dips could be controlled by increasing the time between shearing and dipping. DESIGN: A controlled treatment trial where only the time between shearing and dipping was varied. ANIMALS AND PROCEDURE: One hundred and ninety-five sheep were found to be negative for C. pseudotuberculosis exposure by assay of CLA toxin antibody, were divided into four treatment groups. Each was shorn at either 0, 2, 4 or 8 weeks before dipping in a solution containing C. pseudotuberculosis. Blood samples were taken 6 weeks after dipping and sheep were slaughtered 12 weeks after dipping. A fifth smaller group of 14 sheep shorn 26 weeks before dipping, was also exposed to C. pseudotuberculosis and was slaughtered with the other sheep. RESULTS: The occurrence of caseous lymphadenitis abscesses did not differ between groups or with sheep shorn 26 weeks before dipping. The proportion of sheep that seroconverted to the C. pseudotuberculosis toxin and cell wall ELISA was larger in sheep dipped immediately after shearing than in sheep in the other groups. CONCLUSIONS: Delaying dipping until 8 weeks after shearing did not decrease the C. pseudotuberculosis infection rate due to dipping. Sheep dipped immediately after shearing developed higher concentrations of antibody to C. pseudotuberculosis than sheep when dipping occurred between 2 and 8 weeks and later after shearing.     

Antimicrobial susceptibility patterns of respiratory tract pathogens from sheep and goats

OBJECTIVE: To determine the antimicrobial susceptibility of common respiratory tract pathogens from sheep and goats. DESIGN: Cross-sectional study. SAMPLE POPULATION: 41 respiratory tract isolates from sheep and 36 isolates from goats. PROCEDURES: Disk diffusion assay was used to determine antimicrobial susceptibility of isolates to amoxicillin-clavulanic acid, ceftiofur, ciprofloxacin, florfenicol, and tetracycline. Minimum inhibitory concentrations of florfenicol for these isolates were determined by use of the microbroth dilution technique. RESULTS: The most common isolates were Pasteurella multocida (n = 28) and Mannheimia haemolytica (39). All isolates were susceptible to amoxicillin-clavulanic acid, ceftiofur, ciprofloxacin, and florfenicol. Five percent (4/77) of isolates were resistant to tetracycline. CONCLUSIONS AND CLINICAL RELEVANCE: Susceptibility of respiratory tract pathogens isolated from sheep and goats to commonly used antimicrobial drugs in this study was high. Treatment of these species for bacterial respiratory tract disease is likely not complicated by antimicrobial resistance.     

Occurrence and antimicrobial resistance of emergent Arcobacter spp. isolated from cattle and sheep in Iran

This study is conducted to determine the occurrence and antimicrobial resistance of Arcobacter spp. isolated from clinically healthy food animals. A total of 308 samples from cattle (200) and sheep (108) were collected from Shiraz slaughterhouse, southern Iran to investigate the presence of the important Arcobacter spp. using cultivation and Polymerase Chain Reaction (PCR) methods. Antimicrobial susceptibility of Arcobacter isolates was determined for 18 antibiotics using disk diffusion method. Among 308 samples, 27 (8.7%) and 44 (14.28%) were positive for the presence of Arcobacter species with cultivation and PCR procedures, respectively. The predominant species was A. butzleri in both cattle (58.33%) and sheep (55%). In addition, concurrent incidence of the species was observed in 25% of the positive samples. All Arcobacter isolates were resistant to rifampicin, vancomycin, ceftriaxone, trimethoprim and cephalothin. The isolates showed high susceptibility to tetracycline, oxytetracycline, erythromycin, ciprofloxacin, kanamycin, amikacin, gentamicin and enrofloxacin. No significant difference among cattle and sheep isolates in resistance pattern was observed. The results indicate that cattle and sheep are significant intestinal carriers for Arcobacter spp. Moreover, tetracycline and aminoglycosides showed great effects on Arcobacter species in antibiogram test and can be used for treatment of human Arcobacter infections.     

Genetic diversity among Escherichia coli O149:K91 strains isolated from pigs with diarrhoea determined by randomly amplified polymorphic DNA analysis.

The genetic relatedness among 72 Escherichia coli strains of serotype O149:K91 isolated from pigs with diarrhoea was investigated by randomly amplified polymorphic DNA (RAPD) analysis. Fimbrial and toxic virulence markers of the isolates were also tested. Amplification with primer 1254 resulted in three different RAPD types whereas primer 1290 generated one RAPD profile only. Based on the RAPD and fimbrial/toxin types the strains were classified into five distinct groups.     

Molecular epidemiology of clinical isolates of Pseudomonas aeruginosa isolated from horses in Ireland

Clinical isolates (n = 63) of Pseudomonas aeruginosa obtained from various sites in 63 horses were compared using ERIC2 RAPD PCR to determine their genetic relatedness. Resulting banding patterns (n = 24 genotypes) showed a high degree of genetic heterogeneity amongst all isolates examined, indicating a relative non-clonal relationship between isolates from these patients, employing this genotyping technique. This study characterised 63 clinical isolates into 24 distinct genotypes, with the largest cluster (genotype E) accounting for 10/63 (15.9%) of the isolates. ERIC2 RAPD PCR proved to be a highly discriminatory molecular typing tool of P. aeruginosa in isolates recovered from horses. With the adoption of several controls to aid reproducibility, this technique may be useful as an alternative to PFGE, particularly in epidemiological investigations of outbreaks where speed may be a significant parameter. This is the first report of clonal heterogeneity amongst P. aeruginosa from horses and demonstrated that ERIC RAPD PCR is a rapid method for the examination of this species in horses, which may be useful in outbreak analysis.     

多重PCR检测圈养牛、猪和羊源魏氏梭菌

采用多重PCR对圈养源魏氏梭菌的α，β，ε，ι毒素基因进行了检测，结果证实该方法具有很高的特异性。通过对山东德州、枣庄、泰安、蒙阴曾经流行过魏氏梭菌病的猪场、牛场和羊场的162个粪便样品进行检测，检出率为19．1％，均为A型。应用该方法鉴别魏氏梭菌血清型快速、简便，结果对于预防治疗均具有重要的指导作用。