Prevalence and distribution of VRE (vancomycin resistant enterococci) and VSE (vancomycin susceptible enterococci) strains in the breeding environment

Krzysztof Skowron 1  ,  
Department of Microbiology, Faculty of Pharmacy, Nicolaus Copernicus University in Toruń, Collegium Medicum of L. Rydygier in Bydgoszcz, Poland
Department of Microbiology and Food Technology, University of Technology and Life Sciences, Bydgoszcz, Poland
Ann Agric Environ Med 2016;23(2):231–236
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 lead 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, and determination of the contribution of VRE (vancomycin resistant enterococci) strains and their resistance. The degree of relationship between isolates of each species from genus Enterococcus was also determined.

Material and Methods:
195 isolates were obtained, from which DNA was isolated. Genus identification was conducted with the primers specific to the 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 a 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 the PCR-RAPD method.

Among the 195 isolates, 133 (68%) belonged to E. hirae. The other species contributions were respectively: 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. 60 genetically different strains were defined. The possible contamination paths involved animal feed and spreading of excrements by slaughtered individuals or on personnel’s footwear.

The obtained results indicate a very low percentage of VRE strains in the tested piggery, resulting in a low health risk to piggery, slaughterhouse or abattoir employees.

Krzysztof Skowron   
Department of Microbiology, Faculty of Pharmacy, Nicolaus Copernicus University in Toruń, Collegium Medicum of L. Rydygier in Bydgoszcz, Poland
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