ABSTRACT
Introduction: Escherichia coli is present in the normal intestinal flora but some strains can cause intestinal and extraintestinal diseases, and research on its presence in food of animal origin is in the interests of public health. This study was designed to characterise E. coli strains according to their origin, their carriage of virulence genes specific for certain pathogroups, and phylogenetic group affiliation. Material and Methods: The study was carried out on 100 E. coli strains isolated from food samples of various animal origin as well as pig and cattle carcass swabs. Isolation of the strains was performed using two methods. One method included colony count and the other an overnight enrichment of the samples. Isolation was followed by DNA extraction and detection of virulence genes and phylogenetic group with conventional and multiplex PCRs. Results: In this study, the most prevalent gene was EAST1 (20%) and strains which carried it were identified as enteroadherent E. coli. Other pathogroups were represented in lower incidences. Phylogenetic group analysis revealed the prevalence of the A and B1 groups, with B1 mainly present in game and cattle strains, while the majority of pig and poultry strains were assigned to group A. Conclusion: This study provides an overview of the presence of potentially pathogenic strains and E. coli phylogenetic groups in Croatia, for which the data are limited. Further microbiological and molecular research is required to examine the epidemiological situation in the country.
ABSTRACT
In this study, the presence of Listeria monocytogenes was assessed along the production process of fermented sausages in a small-scale facility. Following the isolation of the pathogen from the final product (ISO 11290-1), retrospective sampling was performed during the production of a new batch of sausages, including raw materials, casings, additives, sausage mixtures, sausages during fermentation, and environmental samples. L. monocytogenes was recovered from the following sampling points: the defrosting room and the cuttering, mixing, stuffing, and fermentation phases. Ten strains were isolated, molecularly confirmed as L. monocytogenes by means of a molecular detection system, and subjected to pulsed-field gel electrophoresis (PFGE) typing. On the basis of an unweighted pair group method with arithmetic mean (UPGMA) dendrogram from Ascl pulsotypes, the strains were indistinguishable (no band difference). The same pulsotypes of strains present in both batches of sausages, as well as in environmental samples, indicated the persistence of L. monocytogenes in the sausage production unit.
ABSTRACT
A total of 156 tonsils and 156 mandibular lymph nodes from fattening pigs originating from 13 farms were sampled in Croatian slaughterhouses and examined for Salmonella spp. (n=78 per organ) and Yersinia enterocolitica (n=78 per organ) by cultural methods. Salmonella was isolated from two tonsils only, both originated from animals from the same farm (5.12%), while Y. enterocolitica were recovered from 26 tonsils (33.33%) which could be traced back to 10 farms. Salmonella was absent in mandibular lymph nodes, and Y. enterocolitica was isolated from eight lymph nodes (10.25%) which originated from six farms. Y. enterocolitica was present inside the lymph nodes of two pigs. The high prevalence of Y. enterocolitica in/on pig tonsils could be the result of cross-contamination during splitting the carcasses with head. This procedure may result in higher prevalence of Y. enterocolitica on surface of mandibular lymph nodes than in their depth. Traditional veterinary postmortem examination of pig halves will not necessarily contribute to cross-contamination with Salmonella or Yersinia under conditions of present slaughter practice.
