Association of virulence genes with mecA gene in Staphylococcus aureus isolates from Tertiary Hospitals in Nigeria.
Date
2015-10
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Abstract
Introduction: Staphylococcus aureus is the etiological agent for a wide range
of human infections, and its pathogenicity largely depends on various virulence
factors associated with adherence, evasion of the immune system and damage of
the host. This study determined the prevalence of methicillin-resistant S. aureus
(MRSA) and some selected virulence genes in clinical isolates of S. aureus from
South-Western Nigeria. Materials and Methods: The antibiotic susceptibility
of 156 S. aureus isolates to various antibiotics was determined. Moreover,
polymerase chain reaction detection of the mecA gene was performed including
SCCmec typing, and the isolates were screened for selected genes (alpha
hemolysin [hla], intracellular adhesion A [icaA], Panton-Valentine leukocidin
[PVL], fibronectin binding protein A [fnbA], bone sialoprotein binding protein [bbp],
exfoliative toxin A [eta], exfoliative toxin B [etb], and collagen binding adhesion
[cna]) associated with virulence. Results: The prevalence of mecA gene was
42.3% (66 out of 156 S. aureus), and SCCmec typing showed that 24 (36.4%)
carried the SCCmec II element, 4 (6.1%) with type III, 10 (15.2%) with SCCmec
IV, and 28 (42.4%) harbored type V. The proportion of S. aureus with the following
genes was ascertained: Hla (55.1%), icaA (42.3%), PVL (34.6%), fnbA (8.3%),
bbp (4.5%), and eta (3.8%). All the isolates were etb and cna negative. The
prevalence of the PVL gene in methicillin susceptible Staphylococcus aureus
(MSSA) was 53.3% compared with 9.1% of MRSA. An association between
virulence genes (eta and icaA) and mecA positive S. aureus; and significant
difference in the distribution of virulence genes in in-patients and out-patients
were found. The MRSA strains in South-Western Nigeria were dominated by
SCCmec II and SCCmec V. Conclusion: The study concluded that there is a
high prevalence of MRSA in Nigeria with association of eta and icaA genes with
mecA gene in S. aureus isolates.
Description
Keywords
mecA, Staphylococcus aureus, virulence genes
Citation
Alli Oyebode Armstrong Terry, Ogbolu David O, Shittu Adebayo O, Okorie Anthony N, Akinola John O, Daniel John B. Association of virulence genes with mecA gene in Staphylococcus aureus isolates from Tertiary Hospitals in Nigeria. Indian Journal of Pathology & Microbiology. 2015 Oct-Dec 58(4): 464-471.