Aminoglycosides modifying enzymes genes among the population of enterococci in Tehran
MM Feizabadi , S Sayady , L Shokrzadeh , S Khatibi , S Gharavi IJMM 2007; 1(1):11-16 ICID: 492265
Article type: Original article
IC™ Value: 3.25
Abstract provided by Publisher
Background and objectives: Resistance to high level concentration of gentamicin is widespread among isolates of enterococci at Tehran Hospitals. To understand the mechanism of resistance among the Iranian isolates, we screened a collection of E. faecalis and E. faecium isolates to detect aminoglycoside modifying enzymes genes.
Material and Methods: To detect the high level gentamicin resistant isolates of enterococci (HLGR phenotype, MIC>500 µg/ml), 114 clinical isolates of E. faecalis (n=79) and E. faecium (n=35) were tested with disks containing 120 µg of gentamicin. The macrobroth dilution assay was then used to determine the minimum inhibitory concentration of gentamicin. The susceptibility of isolates against amikacin, netilmicin, tobramycin, kanamycin were also determined by Kirby-Bauer method. All isolates were subjected to polymerase chain reaction assays targeting aminoglycoside modifying enzyme (AMEs) genes including aac(6′)-aph(2″) , aph(2″)-Ib, aph(2″)-Ic, aph (2″)-Ia, aph (2″)-Id. aph(3')-IIIa and ant(4′)-Ia.
Results: All isolates with HLGR phenotype and those showing 64
Conclusion: The aac(6′)-aph(2″) was the most frequent gene encoding resistance to gentamicin and other aminoglycosides followed by aph(3')-IIIa. Isolates lacking these genes were susceptible to all aminoglyocosides used in this study.