Isolation and identification of glycopeptid-resistant enteroccus species

In the held of human medicine in the last time, several strains of the ente rococcus (E.) genus have been gaining significance as facultative pathogeni c agents. While as recently as 10 years ago enterococci did not figure as n osocomial septic agents, today they are held responsible fur a fifth of all general septic infections, This rise is caused of all to the special capab ility of these agents to develop resistance to substances with anti-microbi al effects. The target of the study was to demonstrate the incidence and resistance beh aviour of vanycomycin-resistant enterococci (VRE), as well as the connectio ns between the different types of resistance to glycopeptide and the use of Avoparcin in livestock production. Avoparcin is a glycopeptide: it was use d in livestock breeding as performance booster and has ii structural formul a similar to that of Teicoplanin and Vancomycin. Since January 1996. howeve r, the use of Avoparcin has been outlawed due to the fact that it must be a ssumed that cross-over resistances can develop and lead to the creation of a resistance pool. The samples examined are isolated from poultry-breeding farms. In order to investigate the potential links described above, enterprises with different operating forms were chosen. These were conventional poultry farms, on the one hand, i.e. large-scale operations which potentially use of Avoparcin ( until its prohibition) as feed additive, and on the other hand ecological o perations. i.e. small-scale farms raising livestock without medicinal addit ives in feed. To collect data on a spectrum as wide as possible, samples were taken from the following areas: poultry house, slaughterhouse. and carcass. From the various areas 223 samples were taken, and 281 VRE strains were iso lated, Initially, the species was identified in line with culture-morpholog ical, biochemical and serological criteria. Once this was done. the glycope ptide sensitivity was tested by means of the microdilution method. 60.1% of all samples (small-scale farms and large-scale farms) proved to be VRE pos itive, 87.8% of all samples originated from conventional large-scale farms. and 30.5% of all samples from small-scale farms. In the case of the VRE is olates. these were exclusively E. faecium strains with high-level resistanc e behaviour. In relation to the bacterial contamination (total viable count, Enterobacte riaceae: and enterococcus spp.) samples from conventional production in gen eral were less contaminated than those derived from ecological operations.