Decreased Incidence of VanA-type Vancomycin-Resistant Enterococci Isolated from Poultry Meat and from Fecal Samples of Humans in the Community after Discontinuation of Avoparcin Usage in Animal Husbandry

Abstract

The use of the glycopeptide antibiotic avoparcin (AVO) as a feed additive in animal husbandry of many European countries led in 1994-1995 to frequent isolation of VanA-type vancomycin-resistant enterococci (VRE) from commercially produced animal foodstuffs as well as from fecal samples of nonhospitalized persons in Germany (Saxony-Anhalt state). However, at the end of 1997, a decreasing number of such VRE was detected in frozen and fresh poultry meat (chickens and turkeys) from German producers. At this point in time, AVO had been discontinued in animal husbandry for more than 2 and one-half years in Denmark/Norway, nearly 2 years in Germany, and about 8-9 months in all countries of the European Community and Switzerland, respectively. VRE were then only detected in very low concentrations in one-quarter of the poultry meat samples (eight of 31, originating from 18 distinct German producers and bought in 12 different supermarkets). A decline of VRE prevalence was also observed in the gut flora of healthy persons (VRE carriers) in the same region (Saxony-Anhalt state, Germany), having fallen from 12% (12/100) in 1994 when AVO was being used to 6% (6/100) in 1996 and 3% (13/400) in 1997 after it was discontinued. These results likely indicate the importance of antibiotic selective pressure by glycopeptides such as AVO for the presence of VRE in animal meat products from commercial animal husbandry. Additionally, it underlines the role of animal products for the spread of resistant bacteria and transferable resistance genes to humans in the community.

Resistance to antibiotics in the normal flora of animals

“…A decline in the number of VRE carriers among the human population from 12% in 1994 to 6% in 1996 and 3% in 1997 was detected in the Saxony-Anhalt region in Germany [23].…”

“…Since 1997 there has been a ban on the use of avoparcin in feed for farm animals in Europe and the occurrence of VRE has declined in poultry meat [23]. A decline in the number of VRE carriers among the human population from 12% in 1994 to 6% in 1996 and 3% in 1997 was detected in the Saxony-Anhalt region in Germany [23].…”

Current Trends of Emergence and Spread of Vancomycin-Resistant Enterococci

“…In countries within the EU, avoparcin was abandoned in Norway and Denmark in 1995, Germany 1996 and in the remaining EU countries in 1997. Studies performed in some European countries soon after identified a reduced prevalence of VRE, their numbers dropped qualitatively and quantitatively in samples from commercial animal farms, food samples and following the food chain in humans of the general population (Klare et al, 1999). However, studies from Denmark and Norway showed that other antimicrobial growth promoters may lead to a coselection phenomenon and reduced VRE numbers were only documentable when other growth promoters like macrolides (spiramycin, tylosin) were also banned.…”

Performance of three chromogenic VRE screening agars, two Etest® vancomycin protocols, and different microdilution methods in detecting vanB genotype Enterococcus faecium with varying vancomycin MICs

“…Diagnostic and university laboratories send strains to us for (vancomycin/teicoplanin) resistance confirmation and molecular typing. Our enterococcal strain collection currently contains > 10,000 isolates, mainly from hospital surveillance and infections, but also from animals, food products, the environment, and stool colonisations in outpatients (Klare et al, 1995a, Klare et al, 1995b, Klare et al, 1999, Klare et al, 2005, Werner et al, 2007, Werner et al, 2010and Werner et al, 2011a. Until now, we collected and identified 1060 vanB strains including 982 vanB-positive E. faecium and 74 vanB-positive E. faecalis which were all from hospital patients.…”