Detection of hemolysine genes in methicillin-resistant S. aureus isolates obtained from a healthy population in north-west of Iran

Abstract

Introduction and objectivesMethicillin-resistant Staphylococcus (S.) aureus (MRSA) is responsible for clinical infections ranging from minor skin infections to severe infections. Alpha hemolysin (hla) and beta hemolysin (hlb) are the most common virulence factors in S. aureus. The current study was aimed to detect hla and hlb genes in nasal methicillin-resistant S. aureus isolates in the student population. Materials and methodA total of 1420 nasal samples were obtained from 23 different high schools in Tabriz city. After confirmation of S. aureus strains by standard biochemical tests, the antibiotic resistance pattern was determined by the disk diffusion method. The presence of mecA, hla, and hlb genes was examined by PCR reaction. ResultOf 1420 samples, 14.30% (203 cases) were positive S. aureus. Among them, 18.72% (38/203) of the isolates were MRSA based on disk diffusion. Based on results, more than 90% of the isolates were susceptible to chloramphenicol, ciprofloxacin, and cefazolin, suggesting that these drugs may indicate better function to treat MRSA infections. The existence of mecA, hla, and hlb genes was observed in 56.16%, 88.18%, and 62.07%, respectively. There is a significant relationship between the prevalence of hla and frequency of the macA gene (p = 0.049), while the rate of hlb was independent on mecA. Discussion and conclusionThe increasing prevalence of hla/hlb positive S. aureus isolates indicates an essential need to monitor nasal carriers in a healthy community to prevent subsequent infections.