title: Association of virulence genes with mecA gene in Staphylococcus aureus isolates from Tertiary Hospitals in Nigeria.
abstract: BACKGROUND
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Biomedical Sciences, College of Health Sciences, Ladoke Akintola University of Technology, Osogbo Campus, Nigeria.
authors.forename: Oyebode Armstrong Terry
authors.initials: OA
authors.lastname: Alli
authors.forename: David O
authors.initials: DO
authors.lastname: Ogbolu
authors.forename: Adebayo O
authors.initials: AO
authors.lastname: Shittu
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Okorie
authors.forename: John O
authors.initials: JO
authors.lastname: Akinola
authors.forename: John B
authors.initials: JB
authors.lastname: Daniel
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D003430:Cross-Sectional Studies; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D009549:Nigeria / Q000453:epidemiology; D046915:Penicillin-Binding Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D062606:Tertiary Care Centers; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D046915:Penicillin-Binding Proteins; D037521:Virulence Factors; C487789:mecA protein, Staphylococcus aureus