[Current status of aminoglycoside resistance in hospital Enterobacteriaceae]

We studied the susceptibility of Enterobacteriaceae to four aminoglycosides (gentamicin, tobramycin, netilmicin et amikacin). We determined their phenotypes of resistance by taking into account both the critic concentrations of the CFA (french committee for antibiogram) and the MIC of the main susceptible population of each species. The most frequent phenotypes were GTNt, TNtA and GTNtA. Amikacin resistance including phenotypes were essentially found in Klebsiella and Serratia (35% and 53% of the strains, respectively); with respect to amikacin, the phenotype expression may be insufficient to exceed the sensitive critic concentration of the CFA. Amikacin resistant strains were isolated from chronically infected patients with devices, such as urinary catheters or tracheal cannula. These results suggest a strains or plasmids outbreak.