Exploring the incidence potential of phenol-soluble modulins among methicillin-resistant Staphylococcus aureus in Lahore, Pakistan.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major clinical and epidemiological problem over the past few decades. This study aimed to investigate antibiotic resistance patterns, incidence potential of phenol-soluble modulins (PSMs) genes and explored the associations between miscellaneous clinical specimens of MRSA and the incidence of virulent PSMs genes.

Methods: This investigation employed a total of sixty MRSA strains isolated from clinical specimens such as pus aspirates, wound swabs, ear swabs, tissue swabs, blood, and urine. Antibiotic profiling was performed via Kirby-Bauer (KB) disk diffusion method. Genetic analysis was performed for detection of S. aureus-specific 16SrRNA gene, methicillin-resistant mecA and its homologue mecC gene and the virulent determinant PSMs genes psm-α, psm-β, and psm-mec along with agr operon gene via polymerase chain reaction (PCR). Pearson's Chi-square (χ²) analysis test was used to determine the associations between various clinical specimens and the incidence of PSMs genes, with a significance threshold set at p < 0.05.

Results: Most of MRSA isolates were obtained from pus samples. The incidence of MRSA was more pronounced in males. Notably, the highest percentage of MRSA isolates was isolated from patients aged 21-40 years. Of all isolates (100%) harboured the 16SrRNA and mecA gene, whereas none of those isolates (0%) had the mecC gene. The resistance profiles of MRSA isolates obtained from various clinical specimens were not significantly different (p > 0.05). Furthermore, vancomycin and linezolid were still effective for treating MRSA infections. Those 60 strains had 56/60 (93.4%) psm-α, 54/60 (90%) psm-β, 55/60 (91.6%) psm-mec and (48/60) 80% agr genes. A strong association was detected between the psm-β gene and MRSA strains obtained from pus samples (p = 0.01), as was the case for the psm-mec gene and MRSA strains obtained from pus samples (p = 0.03).

Conclusion: The well-informed decisions could be made on the prescription of the best antibiotic therapy, the implementation of efficient control measures, and the development of anti-virulence strategies to stop the dissemination of MRSA in hospitals and clinical settings. The virulence factors PSMs may be considered as potential candidates for treating virulent MRSA infections in patients through anti-virulence strategies.