Prevalence of mecA gene among staphylococci from clinical samples of a tertiary hospital in Benin City, Nigeria.

Ephraim Ehidiamen Ibadin1, Idahosa Onaiwu Enabulele2, Fowora Muinah3
1. Medical Microbiology Unit, Medical Laboratory Services, University of Benin Teaching Hospital,
Benin City, Nigeria.
2. Department of Microbiology, Faculty of Life Sciences, University of Benin, Benin City, Nigeria.
3. Molecular Biology and Biotechnology Division, Nigerian Institute of Medical Research, Yaba, Nigeria.

Abstract
Background: The staphylococci have increasingly been associated with infections worldwide and anti-microbial resistance has
made these versatile pathogens more recalcitrant in the hospital setting.

Objectives: This study sought to investigate the occurrence and distribution of Staphylococcus species as well as determine the
prevalence of methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase negative staphylococci (MRCoNS)
among clinical samples from University of Benin Teaching Hospital (UBTH) in Benin City.

Methods: Ninety one (91) clinical isolates comprising S. aureus and Coagulase Negative staphylococci (CoNS) were recovered from
routine clinical specimens and anti-microbial susceptibility tests were carried out. Polymerase Chain Reaction (PCR) was thereafter carried out on these isolates to detect mecA gene.

Results: Staphylococcus species had its highest prevalence from infected wounds of patients (28.8%) while urine samples showed
the least (5.4%). The highest level of resistance was to ceftazidime (S. aureus – 68%, CoNS – 75.6%) while the least resistancenwas observed for meropenem (S. aureus– 26%, CoNS- 46.3%). Using phenotypic method (with 1µg oxacillin antibiotic disc), the distribution of MRSA and MRCoNS was 44.0% and 46.3% respectively. PCR analysis showed that 38.0% of S. aureus and 41.5%  of the CoNS had mecA gene respectively; wound swabs showed the highest prevalence with 30.5% of staphylococcal isolates being mecA gene positive. There was also no signifcant association between the Staphylococcal isolates and their isolation rate, isolation site and mecA gene distribution (p > 0.05).

Conclusion: This study draws attention on the increase in the prevalence of mecA gene (39.6%) and an increase in multidrug
resistant staphylococci when compared to previous studies in our country; it recommends laboratory guidance and periodic review
to stem the tide of resistance.

Keywords: Staphylococcus aureus (S. aureus), coagulase-negative staphylococci (CoNS), mecA gene, methicillin-resistance.