Published: 2017-02-06

Prevalence of aac (6′)-Ie-aph (2″)-Ia gene and drug resistance pattern of Enterococcus isolated in a tertiary care hospital

Ayan K. Das, Shyamasree Nandy, Mridu Dudeja


Background: Enterococci causes serious infection due to its higher ability to colonize and increasing resistance to various drugs. Mutation and plasmid mediated genetic exchange are the main reason for the high rate of acquisition of antibiotic resistance. The study was aimed to determine the antibiotic resistance profile of the enterococcal isolates from various clinical samples and to detect the presence of aac (6′) Ie-aph (2″) Ia gene in the isolates which show phenotypic high level gentamicin resistance.

Methods:Clinical enterococcal isolates from a tertiary care hospital in southern Delhi were subjected to antibiotic susceptibility testing.  MIC for High level gentamicin was measured and the isolates were tested for presence of aac (6′) Ie-aph (2″) Ia gene by PCR.

Results: Out of the total 146 Enterococcal isolates, 112 were E. fecalis, 33 were E faecium and 1 was E gallinarum. 26.02% were resistant to High level gentamicin, and 15% were resistant to streptomycin. Vancomycin resistance was 5.4%. 11 E. fecalis and 25 E. faecium isolates showed presence of aac (6′) Ie-aph (2″) Ia gene.

Conclusions:High level antibiotic resistance among enterococci and the spread of vancomycin resistant is an issue of serious concern. Isolation rate of E. fecalis was much higher than E. faecium, but aac (6′) Ie-aph (2″) Ia gene was more prevalent in E.faecium. The study highlights spread of the gene aac (6′)-Ie-aph (2″)-Ia among the enterococcal isolates which can be easily transferred to other pathogenic gram positive cocci.


Enterococci, HLGR, VRE

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