Dissemination of Virulence Factors and Antimicrobial Resistance in Faecal Enterococci from Poultry

Abstract

Epidemiological studies have emphasized the importance of Enterococcus spp. in regard to positive and negative role of these bacteria. Presented work investigated a relationship among some factors (cytolysin, gelatinase, esp and biofilm formation) on phenotypic and genotypic level in relation to antibiotic resistance (gentamicin -GEN, streptomycin- STR, and vancomycin-VAN) in 82 enterococcal isolates (18 isolates of Enteroccus faecium, 26 of E. faecalis, 35 of E. casseliflavus and 3 of E. gallinarum) taken from cloacal swabs of poultry and from the water intended for livestock breeding. For phenotypic determination, commercial cultivation methods were used. Genes for appropriate factors were detected by polymerase chain reaction. Among tested isolates, 53 (65%) carried gelE gene and consequently 43 (52%) isolates produced gelatinase. The presence of cyl operon was detected in 53 (65%) and production of haemolysin on horse blood agar was determined in 37 (45%). In 14 (17%) isolates, esp gene was detected, but 28 (34%) isolates including those without esp gene detection were considered as strong biofilm producers. In 11 isolates (13%), all three genes (esp/gelE/cylA) were present contrary to 18 (22%) strains with negative PCR reaction. Resistance to GEN and STR was detected in 1 and 3 isolates respectively. All enterococci tested were susceptible to VAN. No relationship between virulence factors and resistance to antimicrobials was found. The data of this study proved relatively wide distribution of virulence factors among enterococci of animal and environmental origin and suggested that such isolates can be a reservoir of virulence trait.