Zum Vorkommen von Gentamicin resistenten Enterokokken von Rindern, Schweinen und Geflügel sowie Lebensmitteln in Deutschland

In the framework of a nationwide study, enterococci were isolated from material of animal origin (cattle, pork, poultry) and food in order to examine their gentamicin resistance. The minimum inhibitory concentration (MIC) values were determined by the microdilution method (Sensititre(R)-system) and additionally by Etest(R) for high-level resistant isolates. The majority of the examined isolates showed MIC values from 1 mug/ml to 64 mug/ml (n = 745 of a total of 862 isolates). Four genes responsible for the gentamicin resistance (aac(6')-le-aph(2")-la, aph(2")-lb, aph(2")-lc, aph(2")-ld) have been investigated by PCR. All gentamicin high-level resistant isolates (n = 9 with MIC values greater than or equal to 500 mug/ml) possessed the first mentioned gene. The three remaining genes were neither detected in these isolates nor in isolates with MIC values against gentamicin from 32 to 256 mug/ml. The nine isolates were identified as E faecalis and E gallinarum by biochemical tests and PCR. Dependent on their species, they showed the same resistance patterns against the 16 selected antimicrobial agents. In fingerprint studies using PFGE, all high-level resistant E faecalis isolates showed the same restriction fragment pattern independent of the source of material (minced meat, pig, ham) and the region. For the E gallinarum isolates, however, analysable fragment patterns could only be determined for that isolated from poultry. All other E gallinarum isolates could be differentiated neither with the restriction enzymes Smal nor with Apal. According to the presented results, the occurrence of gentamicin high-level resistant entercocci isolated from animals is small