医学微生物学与诊断

Molecular Detection of Panton-Valentine Leukocidin (PVL) Toxins in Clinical Isolates of Staphylococcus aureus from Maitama District Hospital, Abuja, Nigeria

Abstract

Orji OL, Olayinka BO, Afolabi B, Ejikeugwu Chika P, Nwakaeze EA, Eze CJ, Eluu SC and Agbom C

Pathogenic Staphylococcus aureus is the most frequently isolated Gram positive bacterium from clinical specimens; and it is among the leading cause of infection in man. S. aureus has gained significant interest in recent years as an important nosocomial pathogen – owing to its multidrug resistant nature which is associated to several virulence factors of the organism including Panton-valentine leukocidin (PVL). PVL is part of the toxins produced by pathogenic S. aureus – which help the organism to exacerbate their pathogenicity/virulence in the phase of an infection. This study evaluated the prevalence of PVL-positive S. aureus from clinical specimens – owing to the dearth of information on this subject matter in Nigeria. Out of the 118 non-consecutive S. aureus isolates employed for this study, only 56 isolates were biochemically confirmed as pathogenic S. aureus. The antibiogram showed that the S. aureus isolates were most susceptible to gentamicin, vancomycin, ciprofloxacin, erythromycin and linezolid. However, they were highly resistant to the cephamycin, cefoxitin (82.1%). The S. aureus isolates also showed reduced susceptibility to tigecycline (71.4%), clindamycin (66.1%), chloramphenicol (48.2%), amoxicillin-clavulanic acid (53.6%) and sulphamethoxazole-trimethoprim (48.2%). The prevalence of PVL genes in this study was 10.7%. Only 6 isolates of S. aureus (10.7%) were confirmed by PCR to harbour the PVL genes; and these S. aureus isolates were from wound samples, abscess and urine samples. The occurrence of pathogenic S. aureus harbouring drug resistant genes such as PVL genes in the hospital environment pose serious health and therapeutic challenges especially in choosing antimicrobial therapy for treatment. S. aureus isolates with PVL genes could also disseminate with high propensity within the hospital environment; and this could result in the outbreak of nosocomial infections. Continues antibiotic stewardship in our hospitals will help in the control and prevention of the emergence and dissemination of drug-resistant microbes in both the community and hospital environment.