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The prevalence and distribution in the breeding environment the VRE (vancomycin resistant enterococci) and VSE (vancomycin susceptible enterococci) strains

Department of Microbiology, Faculty of Pharmacy, Nicolaus Copernicus University in Toruń, Collegium Medicum of L. Rydygier in Bydgoszcz
Department of Microbiology and Food Technology, University of Technology and Life Sciences, Bydgoszcz, Poland
Introduction and objective: Intensive animal production causes numerous problems. Facilities connected with animal maintenance not only cause environmental pollution but also pose a great sanitary and epidemiological threat. Long term use of antibiotics in animal production led animal-borne microorganisms to develop multiple resistance mechanisms, transferred to the typical environmental bacteria. The aim of this study was assessment of E. faecalis, E. faecium, E. durans and E. hirae prevalence in samples gathered from swine production sectors, determination the contribution of VRE (vancomycin resistant enterococci) strains and their resistance. Moreover, degree of relationship between isolates of each species from genus Enterococcus was determined. Materials and methods: There were 195 isolates obtained, from which DNA was isolated. Genus identification was conducted with the primers specific to 16S rRNA region and identification of the species with primers specific to sequence of gene sodA in Multiplex PCR reaction. Resistance to vancomycin (6 μg×ml 1) was tested using screening method on Muller Hinton Agar. To assess resistance type Multiplex PCR, amplifying products corresponding to genes VanA, VanB and VanC, was conducted. Genotyping was conducted using PCR-RAPD method. Results: Among 195 isolates, 133 (68%) belonged to E. hirae. The other species contributions were correspondingly: E. faecalis - 21%, E. durans - 8% and E. faecium - 3%. Only 2 isolates of E. hirae, being different strains, were resistant to vancomycin. Both were representing phenotype VanC1. There were 60 genetically different strains defined. The possible contamination paths involved animal feed and spreading of excrements by slaughtered individuals or on personnel’s footwear. Conclusions: The obtained results indicated very low percentage of VRE strains in the tested piggery, resulting in the low health risk to piggery, slaughterhouse or abattoir employees.