Poultry is recognized as the most important source of food-related transmission of Campylobacter jejuni to humans and campylobacteriosis is the most commonly reported zoonotic bacterial disease in the European Union. It has been documented that C. jejuni is genetically diverse and analyses of bacterial isolates usually show a large strain variety. Therefore, molecular typing of strains represents an important tool to study the genetic diversity of isolates and to trace individual strains that cause human infections. The aim of the study was characterization of genetic population structure and antimicrobial resistance (AMR) of C. jejuni isolated from Polish chickens. C. jejuni from chicken ceca and the corresponding carcasses (72 and 61 strains, respectively), originating from 128 flocks in Poland during February 2011 and May 2013, were used in the study. The isolates were tested for their population structure and genetic diversity using a multilocus sequence typing (MLST) scheme with connection to their antimicrobial resistance. The molecular analysis of 133 C. jejuni generated 39 different sequence types (ST); 3 of them were defined for the first time. Additionally, 16 STs were represented by single isolates. The most common STs observed were 6411 (16.5% isolates) and 257 (15.0% strains). The first mentioned ST was resistant to 3 different classes of antibiotics, i.e., quinolones, tetracyclines, and aminoglycosides. Overall, 125 (94.4%) of C. jejuni isolates demonstrated antimicrobial resistance and the most frequent AMR profile observed was ciprofloxacin, nalidixic acid, tetracycline (47.4% strains). Likewise, the clonal complexes CC 257 and CC 353 were defined as the predominant molecular groups covering altogether 37 C. jejuni strains. No associations between CCs and the origin of the samples as well as the place of isolation were found. This study highlights that the C. jejuni population from chickens in Poland was diverse and showed a weak clonal structure.
Introduction: The study objective was to develop and evaluate a new TaqMan multiplex real-time PCR method for Salmonella, L. monocytogenes, and verotoxigenic Escherichia coli (VTEC) detection in slaughtered animal carcasses. Material and Methods: The procedure included an enrichment step, DNA extraction, and two multiplex real-time PCRs. The first PCR detected the invA and hly genes of Salmonella and L. monocytogenes respectively, the second the vtx1, vtx2, and eae genes of VTEC. Results: The validation of this method resulted in 100% relative sensitivity, specificity, and accuracy as compared to the reference ISO methods. The limit of detection per swab sample was established at 1 cfu for Salmonella and L. monocytogenes and 2 cfu for VTEC. The authors analysed 265 slaughterhouse-collected swabs from cattle, pig, and poultry carcasses. Among 125 from cattle, 51 were positive for VTEC, 29 for Salmonella, and 1 for L. monocytogenes. Among swabs from pig carcasses (n = 95), three, two, and one sample were positive for these pathogens respectively. None of the microorganisms tested for was identified in 45 samples of poultry origin. Conclusion: The obtained results showed that the method developed can rapidly identify the main bacterial pathogens that may contaminate carcasses of food-producing animals.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.