Bioscience and Bioengineering Vol. 1, No. 2, 2015, pp. 34-40 http://www.aiscience.org/journal/bio * Corresponding author E-mail address: askumurya.med@buk.edu.ng In Vitro Activities of 7 Antimicrobial Agents Against Methicillin Resistant Staphylococcus aureus Isolates From Northwestern Nigerian Hospitals Abdulhadi Sale Kumurya * Department of Medical Laboratory Science, Faculty of Allied Health Sciences, Bayero University, Kano, Nigeria Abstract Background: Staphylococcus aureus (S. aureus) is an important pathogen in human infections which is implicated in a wide variety of infections, from mild skin infections to more serious and invasive infections. Methicillin resistant S. aureus (MRSA) is one of the major causes of nosocomial infection in hospital setting. Objectives: The study was aimed at determining the distribution of mecA gene among the S. aureus isolates from eight health institutions in Northwestern Nigeria. Methods: A total of 100 isolates of S. aureus were collected from various clinical specimens. Antibiotics susceptibility testing including methicillin sensitivity testing, beta lactamase testing and PCR for detection of mecA gene were carried out on all the 100 isolates of S. aureus. Results: More than half of the total number of isolates 57 (57.0%) were recovered from wound swabs and urine samples. While the remaining 43 (43.0%) were recovered from ear swabs, high vaginal swabs, urethral swabs blood culture, sputum and semen samples.Male preponderance and age range of 21-30 years were the most important demographic findings.All the 100 (100%) strains were MRSA using 10µg methicillin and 5µgoxacillin discs. PCR analysis showed that mecA gene was present only in 5 (5.0%) of the 100 S. aureus isolates tested. Furthermore, all the 100 isolates were β-lactamase producers. That there were strong associations between isolation site of specimens / nature of specimens (Χ 2 = 16.74; p < 0.05) All the isolates were susceptible to vancomycin. Vancomycin, fusidic acid, rifampicin and gentamicin were found to be the most effective drugs against the S. aureus isolates among the antibiotics used. Conclusion: The prevalence of mecA gene in S. aureus in Northwestern Nigeria is 5.0% and mecA gene detection is a good predictor of methicillin resistance in S. aureus in Nigeria, hence use as a method of detection of MRSA. On the basis of this finding; establishment of molecular diagnostic laboratory in secondary and tertiary health units is urgently required. Control of MRSA infection is essential, and it can be achieved by proper implementation of hospital control measures. Keywords Staphylococcus aureus, mecA Gene, MRSA, Antimicrobial Agents, Northwestern Nigeria Received: April 9, 2015 / Accepted: April 29, 2015 / Published online: June 5, 2015 @ 2015 The Authors. Published by American Institute of Science. This Open Access article is under the CC BY-NC license. http://creativecommons.org/licenses/by-nc/4.0/ 1. Introduction Staphylococcus aureus has emerged as one of the most important human pathogens, being over the past several decades a leading cause of hospital and community acquired infections (Lowy, 1998). It is associated with variety of clinical infections including septicemia, pneumonia, wound sepsis, septic arthritis, osteomylitis and post – surgical toxic shock syndrome with substantial rates of morbidity and mortality (Boyce, 1997; Casgrove et al., 2003; Shopsin and