Isolation and characterization of Vancomycin resistant Staphylococcus aureus (VRSA) from Intensive Care Units (ICU) of different hospitals in Lahore, Pakistan

Background: Nosocomial infections present a major threat because of the increased prevalence of clinical cases appearing among both developed as well as developing countries thus resulting in an alarming condition. This descriptive study was designed to determine the prevalence of hospital acquired vancomycin resistant Staphylococcus aureus (VRSA) in intensive care units (ICU) of different hospitals of Lahore. Methods: Sixty three swab samples were collected from different local hospitals in Lahore. The study was conducted at the Department of Microbiology and Molecular Genetics, University of the Punjab, Lahore from 2013 to 2014. Methicillin sensitive Staphylococcus aureus (MSSA), Methicillin resistant Staphylococcus aureus (MRSA) and VRSA were isolated and confirmed using Clinical & Laboratory Standard Institute (CLSI), 2015 guidelines. vanA gene was amplified to determine the molecular basis of resistance of all VRSA isolates by using strain of S. aureus (ATCC 29213) as a gold standard. Results: Prevalence of VRSA is comparatively low in the hospital settings of Lahore than MRSA. Out of sixty three S. aureus, four (6%) isolates were VRSA positive, and eight isolates (17%) showed intermediate resistance. The absence of vanA gene in VRSA showed that mechanism of resistance is other than vanA gene transfer. Conclusions: Presence of VRSA in hospital settings is alarming for health care workers, patients and researchers and it also highlights the importance of alternative medicines to cure infections.