High Prevalence of Panton-Valentine Leukocidin (PVL) Genes in Nosocomial-AcquiredStaphylococcus aureusIsolated from Tertiary Care Hospitals in Nepal

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) carrying the important virulence determinant, Panton-Valentine leukocidin (PVL), is an emerging infectious pathogen associated with skin and soft tissue infections as well as life-threatening invasive diseases. In carrying out the first PVL prevalence study in Nepal, we screened 73 nosocomial isolates of S. aureus from 2 tertiary care Nepali hospitals and obtained an overall PVL-positivity rate of 35.6% among the hospital isolates: 26.1% of MRSA and 51.9% of methicillin sensitive S. aureus (MSSA) isolates were found to be positive for the PVL genes. PVL prevalence was not associated with a specific (i) infection site, (ii) age group, or (iii) hospital of origin. It was found to be positively associated with heterogeneous MRSA (73.3%) compared to homogeneous MRSA (3.2%) and MSSA (51.9%); negatively associated with multiresistant MRSA (22%) compared to nonmultiresistant MRSA (60%) and MSSA (51.9%); and positively associated with macrolide-streptogramin B resistance (93.8%) compared to macrolide-lincosamide-streptogramin B resistance (0%) and no-resistance (45.8%) types. Macrolide-streptogramin B resistance was confirmed by the presence of msr(A) gene. Restriction pattern analyses provided evidence to support the circulation of a limited number of clones of PVL-positive MRSA, arguing for the adaptability of these isolates to a hospital setting.

Molecular Epidemiology of Panton-Valentine Leukocidin Harboring Hospital-Associated Methicillin-Resistant Staphylococcus aureus in Septicemic Children, Northeastern Iran, Bojnurd

“…It seems that PVL carrying phages were integrated into pre-existing endemic MRSA strains; therefore, a previously accepted hypothesis about markers of CA-MRSA strains could be speculated. Our findings and some previous studies suggest that the PVL gene could not be an appropriate marker for CA-MRSA (9,10,27,(37)(38)(39). Altogether, these findings are alarming with respect to the genetic background of these HA-MRSA strains (ST239/SCCmec III), since it is possible that these highly virulent strains spread to other hospitals in various geographical regions.…”

“…Phage harbored Panton-Valentine Leukocidin (PVL) is one of the most important toxins (8). This is a twocomponent toxin encoded by phage that can be inserted into the S. aureus genome (9). This toxin was introduced as one of the CA-MRSA markers, especially in skin and soft tissue infections (10).…”

Methicillin-resistant <i>Staphylococcus aureus</i> isolates from Iranian restaurant food samples: Panton-Valentine Leukocidin, SCCmec phenotypes and antimicrobial resistance

“…Type IV is classified to IVa, IVb, IVc and IVd alleles [9]. Data revealed that PantonValentine Leukocidin (PVL) is the most important virulence factor detected in the MRSA strains isolated from the cases of foodborne and clinical infections [10]. Inappropriately, major principles of food hygiene have not been addressed in most Iranian restaurants.…”

Toxin production and drug resistance profiles of pediatric methicillin-resistant Staphylococcus aureus isolates in Tehran

“…The luk-PV gene was found in 5% of blood and 3% of pharynx samples. Overall, the prevalence of the luk-PV gene has been estimated to be 2-35% among MRSA isolates in various types of nosocomial infections [34,35] Although the association between luk-PV gene and CA-MRSA strains is a subject of debate, to date, PVL has emerged as a significant virulence factor of CA-MRSA isolates making it a putative marker of these strains [37]. In a study conducted by D'Souza et al in Mumbai between 2006 and 2009, it was found that none of the HA-MRSA isolates carried the luk-PV gene [38].…”