Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Investigation of the Genetic Basis of Tetracycline Resistance in Staphylococcus aureus from Pakistan

Farhat Ullah¹ , Salman Akbar Malik², Jawad Ahmed³, Farman Ullah¹, Syed Majid Shah¹, Muhammad Ayaz¹, Sajid Hussain¹, Lubna Khatoon⁴

¹Kohat University of Science and Technology, Kohat; ²Quaid-i-Azam University, Islamabad; ³Khyber Medical University, Peshawar; ⁴University of Agriculture, Faisalabad, Pakistan.

For correspondence:- Farhat Ullah Email: farhataziz80@hotmail.com Tel:+00923339361513

Received: 26 March 2011 Accepted: 13 October 2012 Published: 13 December 2012

Citation: Ullah F, Malik SA, Ahmed J, Ullah F, Shah SM, Ayaz M, et al. Investigation of the Genetic Basis of Tetracycline Resistance in Staphylococcus aureus from Pakistan. Trop J Pharm Res 2012; 11(6):925-931 doi: 10.4314/tjpr.v11i6.8

© 2012 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose: To determine the prevalence and genetic basis of tetracycline resistance in Staphylococcus aureus.

Methods: One hundred and thirty (130) clinical isolates of S. aureus were collected from Khyber Teaching Hospital, Peshawar, Pakistan. Susceptibility to antibiotics (doxycycline, tetracycline and minocycline) was determined by Kirby-Bauer disc diffusion method with minimum inhibitory concentration (MIC) evaluated on Muller-Hinton agar as described by the Clinical and Laboratory Standards Institute (CLSI). The tetracycline-resistant strains (TET-R) were screened by polymerase chain reaction (PCR) for the presence of four common tetracycline resistance determinants, viz, tet(K), tet(L), tet(M) and tet(O).

Results: Sixty (46.0 %) of these isolates were methicillin-resistant S. aureus (MRSA) while 70 (54.0 %) were methicillin-susceptible S. aureus (MSSA). Seventy four (56.9 %) strains were resistant to tetracycline (TET-R), 30 (23.1 %) to minocycline and 23 (17.7 %) to doxycycline. A majority of the MRSA were resistant to tetracyclines and all the MSSA were sensitive to doxycycline and minocycline. The tet(K) gene was found in 58 isolates and tet(L) in one isolate. No tet(M) and tet(O) were detected.

Conclusion: This study indicates that resistance to tetracyclines is mainly by efflux pumps mediated by tet(K) in S. aureus in northwestern Pakistan.

Keywords: Staphylococcus aureus, Antimicrobial susceptibility, Antibiotic resistance, Tetracycline, Pakistan