Increasing Prevalence of High-Level Gentamicin Resistance among Enterococci Isolated in Greece

High-level gentamicin-resistant enterococci (HLGRE) (MIC >512 microg/ml) were frequently recovered in the AHEPA University Hospital, Thessaloniki, Greece, during a 15-month period (67/158, 42.4%). PCR testing showed that high-level gentamicin resistance was attributable to the presence of the aac(6')-aph(2") gene, while the recently described genes aph (2")-Ic and aph(2")-Id were not detected. High-level gentamicin resistance could be transferred with varying frequency from 41 of 57 Enterococcus faecalis and 5 of 10 Enterococcus faecium isolates. All transconjugants acquired high-level resistance to streptomycin. HLGRE cause therapeutic problems in our region, since none of the clinically available aminoglycosides can be used in severe infections.