Molecular detection of mecA and lukSF-PV in patients with Staphylococcus aureus soft tissue infections in a tertiary hospital setting, Calabar, Nigeria: a cross-sectional study.

Abstract

Background: Panton-Valentine Leukocidin (PVL) is one of the major virulence factors known to be associated with invasive, life-threatening Staphylococcus aureus (S. aureus) soft tissue infections. Several studies have shown that methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) are carriers of the lukSF-PV; however, data describing their prevalence and distribution in the Nigerian setting are sparse in the literature, and thus informed the need for the current study.

Objective: We aimed to detect mecA and analysed the risk factors associated with lukSF-PV-producing S. aureus wound infections.

Design: This was a single-centre hospital-based descriptive cross-sectional study conducted between March 2019 and September 2019 at the University of Calabar Teaching Hospital, Calabar, Nigeria.

Methods: Aspirates from participants with soft tissue infections were cultured, and all isolates of S. aureus were tested for the presence of lukSF-PV using endpoint polymerase chain reaction. The mecA was also detected, and antibiotic susceptibility testing was performed.

Results: Eighty S. aureus isolates were identified from 360 participants. Of the eighty, 47 (58.8%) were MRSA and 10 (12.5%) were lukSF-PV-producing S. aureus strains. Of the ten, six were MSSA and four were MRSA, but the difference was not statistically significant. A significant association was observed between lukSF-PV-producing S. aureus-infected wounds and recurrent skin infections (p = 0.024), as well as working in a day care nursery home (p = 0.0008). The majority of S. aureus isolates were susceptible to tigecycline (76%) and vancomycin (76%), followed by susceptibility to linezolid (72.5%), quinupristin/dalfopristin (67.2%), levofloxacin (38.6%) and erythromycin (11.7%).

Conclusion: The prevalence of PVL-positive S. aureus strains causing soft tissue infections in our setting is seemingly high. There is a need for active surveillance of this gene in patients presenting with S. aureus soft tissue infections in our setting, ensure antibiotic susceptibility testing, evaluate the impact of these strains on clinical outcomes and prevent the spread of lukSF-PV-positive S. aureus strains.