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The Scientific World Journal
Volume 2014, Article ID 329157, 5 pages
Research Article

High Level Aminoglycoside Resistance and Distribution of Aminoglycoside Resistant Genes among Clinical Isolates of Enterococcus Species in Chennai, India

1Department of Microbiology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai 600 113, India
2Department of Paediatric Nephrology, Institute of Child Health and Research Centre, Chennai 600 008, India

Received 27 August 2013; Accepted 26 November 2013; Published 4 February 2014

Academic Editors: J. P. Ackers and E. P. Sampaio

Copyright © 2014 Elango Padmasini et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Enterococci are nosocomial pathogen with multiple-drug resistance by intrinsic and extrinsic mechanisms. Aminoglycosides along with cell wall inhibitors are given clinically for treating enterococcal infections. 178 enterococcal isolates were analyzed in this study. E. faecalis is identified to be the predominant Enterococcus species, along with E. faecium, E. avium, E. hirae, E. durans, E. dispar and E. gallinarum. High level aminoglycoside resistance (HLAR) by MIC for gentamicin (GM), streptomycin (SM) and both (GM + SM) antibiotics was found to be 42.7%, 29.8%, and 21.9%, respectively. Detection of aminoglycoside modifying enzyme encoding genes (AME) in enterococci was identified by multiplex PCR for aac(6′)-Ie-aph(2′′)-Ia; aph(2′′)-Ib; aph(2′′)-Ic; aph(2′′)-Id and aph(3′)-IIIa genes. 38.2% isolates carried aac(6′)-Ie-aph(2′′)-Ia gene and 40.4% isolates carried aph(3′)-IIIa gene. aph(2′′)-Ib; aph(2′′)-Ic; aph(2′′)-Id were not detected among our study isolates. aac(6′)-Ie-aph(2′′)-Ia and aph(3′)-IIIa genes were also observed in HLAR E. durans, E. avium, E. hirae, and E. gallinarum isolates. This indicates that high level aminoglycoside resistance genes are widely disseminated among isolates of enterococci from Chennai.