Panton-Valentine Leukocidin Genes and Staphylococcal Cassette Chromosome Mec Types in Methicillin-Resistant Staphylococcus aureus That Causes Hospital- and Community-Acquired Infections.

This cross-sectional descriptive study was conducted at the University of Health Sciences, Lahore, over 5 years (2016-2020) to explore the association of Panton-Valentine leucocidin (pvl) genes and staphylococcal cassette chromosome mec (SCCmec) types with hospital-acquired (HA) and community-acquired methicillin-resistant Staphylococcus aureus (MRSA). Panton-Valentine leucocidin genes in MRSA have been found in HA-MRSA strains, thereby raising the prevalence of highly virulent and resistant strains. Furthermore, the usage of staphylococcal cassette chromosome mec (SCCmec) typing is crucial for understanding the epidemiology and evolution of MRSA. The isolates of Staphylococcus aureus were acquired from clinical samples of the patients. Gram staining, catalase, coagulase, and DNAse tests were used for S. aureus confirmation. The methicillin resistance genes A and C (mecA and mecC) genes were detected to confirm MRSA by using a 30 µg cefoxitin disk. Panton-Valentine leucocidin gene identification and SCCmec typing (types I-V and XI) were conducted through polymerase chain reaction testing. Only 440 strains of MRSA were isolated, and 31.6% were positive for the pvl gene. The most prevalent SCCmec type among the MRSA isolates was type III, which was found in 42.7% of isolates. The pvl gene was detected in 74% of SCCmec types IV and V and in only 14% of SCCmec types I, II, III, and IIIA. This study revealed the dynamic adaptability of MRSA strains within healthcare settings, with the cooccurrence of the pvl gene and various SCCmec types highlighting the complexity of MRSA epidemiology. The urgent implementation of comprehensive strategies that integrate molecular surveillance and infection control measures is crucial for mitigating MRSA.