Distribution of lasl and rhlR virulent gene among Staphylococcus aureus isolates in clinical samples from Ekiti state university teaching hospital, Ado Ekiti, Nigeria

Infection with Staphylococcus aureus has been considered a major problem in hospitals. The clinical importance of S. aureus is attributed to notable virulence factors and genetic diversity. The study aimed to investigate the distribution of lasI and rhlR virulent gene (a quorum sensing system reported in Pseudomonas aeruginosa) and different genotypes in some clinical isolates obtained from Ekiti State University Teaching Hospital, Ado Ekiti. A total of 100 clinical isolates were collected and screened out of which 75 samples with good S. aureus yield were selected for this study. 34 (45.3%) were from males and 41 (54.7%) were from females. The isolates were drawn from across several age groups and sample types. Result showed that most susceptible antibiotics was Ciprofloxacin (64.0 %), while the most resistant antibiotics was Ampiclox (88.0%). Using Polymerase Chain Reaction (PCR), virulent genes lasL and rhiR formed clusters in S. aureus isolates used in this study, lasl was absence in 22 of the isolates and only present in 53 (71%) of the isolates, rhlR was absent in 24 of the isolates and only present in 51 (68%) of the isolates. Virulence diversity was observed among isolates. Furthermore S. aureus was found to harbor lasL and rhlR virulent gene, a quorum sensing system which was only reported in Pseudomonas aeruginosa, revealing the virulent mutants in the isolates which could be used as a guide to the pathogenicity of individual isolates and hence control spread of infection. The genetic typing was carried out by Random Amplified Polymorphic DNA (RAPD-PCR) using OPH06, OPT06, OPT07 and OPHO7, primers. In conclusion there exist different genotypes which are mutants among the S. aureus isolates used in this study revealing high level of genetic diversity occurrence among S. aureus isolates. The DNA fingerprint revealed high genetic diversity among isolates irrespective of their sources.