Association of Panton Valentine Leukocidin (PVL) genes with methicillin resistant Staphylococcus aureus (MRSA) in Western Nepal: a matter of concern for community infections (a hospital based prospective study).

Dharm R Bhatta,Abhishek Gaur,Dwij R Bhatta,Gopal Nath,Kush Kumar,Lina M Cavaco,Shishir Gokhale

doi:10.1186/s12879-016-1531-1

Abstract

BackgroundMethicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. Panton Valentine leukocidin (PVL) is considered one of the important virulence factors of S. aureus responsible for destruction of white blood cells, necrosis and apoptosis and as a marker of community acquired MRSA. This study was aimed to determine the prevalence of PVL genes among MRSA isolates and to check the reliability of PVL as marker of community acquired MRSA isolates from Western Nepal.MethodsA total of 400 strains of S. aureus were collected from clinical specimens and various units (Operation Theater, Intensive Care Units) of the hospital and 139 of these had been confirmed as MRSA by previous study. Multiplex PCR was used to detect mecA and PVL genes. Clinical data as well as antimicrobial susceptibility data was analyzed and compared among PVL positive and negative MRSA isolates.ResultsOut of 139 MRSA isolates, 79 (56.8 %) were PVL positive. The majority of the community acquired MRSA (90.4 %) were PVL positive (Positive predictive value: 94.9 % and negative predictive value: 86.6 %), while PVL was detected only in 4 (7.1 %) hospital associated MRSA strains. None of the MRSA isolates from hospital environment was found positive for the PVL genes. The majority of the PVL positive strains (75.5 %) were isolated from pus samples. Antibiotic resistance among PVL negative MRSA isolates was found higher as compared to PVL positive MRSA.ConclusionOur study showed high prevalence of PVL among community acquired MRSA isolates. Absence of PVL among MRSA isolates from hospital environment indicates its poor association with hospital acquired MRSA and therefore, PVL may be used a marker for community acquired MRSA. This is first study from Nepal, to test PVL among MRSA isolates from hospital environment.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1531-1) contains supplementary material, which is available to authorized users.

Highlights

Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections
The Panton Valentine leukocidin (PVL) positive MRSA isolates showed higher sensitivity against antibiotics as compared to PVL negative isolates indicating that PVL is not associated with drug resistance mechanisms
The presence of PVL among multi drug resistant bacteria like MRSA may be involved in virulence and increase the challenges for clinicians

Summary

Introduction

Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. Panton Valentine leukocidin (PVL) is considered one of the important virulence factors of S. aureus responsible for destruction of white blood cells, necrosis and apoptosis and as a marker of community acquired MRSA. Staphylococcus aureus is one of the most common and important human pathogen associated with broad spectrum of diseases It is a major cause of hospital acquired infection of surgical wounds and infections associated with indwelling medical devices. The Panton Valentine leukocidin was named after Sir Philip Noel Panton and Francis Valentine who associated it with soft tissue infections in 1932 [2, 3] It is a member of the synergohymenotropic toxin family that induces pores in the membranes of cells

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