Distribution and genetic relatedness of vancomycin-resistant enterococci (VRE) isolated from healthy slaughtered chickens in Hungary from 2001 to 2004

Abstract

The presence of the vanA gene was determined in enterococci from healthy poultry, originating from the Hungarian resistance monitoring system between 2001 and 2004. Enterococci (n = 562) were collected from intestinal samples of slaughtered broiler chickens. The presence of van genes was detected by polymerase chain reaction (PCR). The vancomycin-resistant enterococcus (VRE) strains carried only the vanA gene. Genus-and species-level identification of the vanA gene carrier strains was carried out by PCR using specific primers. In 2001, 25 out of the 289 isolated strains (8.6%) were vanA carriers (1 Enterococcus mundtii, 13 E. durans and 11 E. faecium). In 2002 (n = 87), 20 (23%) strains were vanA positive (11 E. durans and 9 E. faecium). In 2003 and 2004, none of the strains (n = 95 and 91, respectively) were positive for the most common van genes. In 2003, there was only one strain for which higher minimum inhibitory concentrations (MIC) of vancomycin (4 mg/L) and teicoplanin (8 mg/L) were found. In 2004 there were three strains for which the MIC of vancomycin was 8 mg/L, and 2 strains and 1 strain with teicoplanin MICs of 4 mg/L and 8 mg/L, respectively. The potential similarity of these strains was studied by pulsed-field gel electrophoresis (PFGE). The VRE strains were not closely related to one another. The annual data of vancomycin resistance indicate an association between the recovery of vancomycin-resistant enterococci and the use of avoparcin in animal feeds. This study indicates that with the reduced use of antibiotics in food animals, it is possible to decrease the rate of resistant bacteria. Although the use of avoparcin had been banned in 1998, the VRE strains disappeared only five years later.

Impacts of Poultry House Environment on Poultry Litter Bacterial Community Composition

“…Only one sequence from each non-GD house recruited to this cluster so the cluster was considered unique, and likely represents a different species or strain than the ones found in the non-GD houses. As a genus, Enterococcus has gained attention in recent years due to the isolation of increasingly antibiotic resistant stains from both clinical and industrial settings [84], [85]. Enterococcus species faecium and faecalis with resistance to numerous antibiotics have been isolated from both poultry litter and poultry transport containers [85], [86].…”

Current Trends of Emergence and Spread of Vancomycin-Resistant Enterococci

“…However, VRE counts did not drop to zero. Studies in animal farms performed several years after the ban of several growth promoters including avoparcin revealed a permanent reservoir of VRE (Borgen et al, 2000;Borgen et al, 2001;Ghidan et al, 2008). Recent studies performed in Swedish animal farms still highlighted a considerable reservoir of VRE (Nilsson et al, 2009b).…”

Antibiotic Resistance Patterns in Faecal E. coli: A Longitudinal Cohort-Control Study of Hospitalized Horses

“…Linked resistance genes encoded on mobile genetic elements, can also contribute to the spread of resistance genes (Srinivasan et al, 2007), with exposure to one antimicrobial agent leading to selection for resistance against other, or multiple, antimicrobial drugs (Braoudaki et al, 2007;Schnellmann et al, 2006;Weese et al, 2006). Such genes can be maintained after antibiotic treatment, has been stopped such that removing the selective pressure does not necessarily lead to the loss of resistance (Ahmed et al, 2010;Kaszanyitzky et al, 2007;Ghidan et al,2008). Mobile genetic elements are widely reported cause of the spread of antibiotic resistance in both E. coli and Salmonella commensals in animals bred for human consumption (Roest et al, 2007).…”