Methicillin and multidrug resistant coagulase negative staphylococcal nasal carriage in medical students.

Awareness of the virulence of coagulase negative staphylococcus (CoNS), previously regarded as commensals with minimal pathogenicity has steadily increased. CoNS is one of the most important nosocomial pathogen in blood stream infections and in patients with intravenous catheters and implants. CoNS also acts as a reservoir of drug resistance genes for S.aureus. The present study was done to know the nasal carriage rate of CoNS and methicillin resistant CoNS (MRCoNS) in medical students, the effect of hospital environment and patient exposure on carriage rate in medical students and to know the sensitivity pattern of CoNS and MRCoNS to different drugs. A total of 104 Medical students were the subjects of the study. Nasal swab was collected from each subject and processed without delay on sheep blood agar plates. CoNS isolated were tested for methicillin resistance and resistance to other drugs by Kirby-Bauer disc diffusion method according CLSI 2011 guidelines. Overall CoNS and MRCoNS nasal carriage was seen in 63.46% and 18.26% of medical students. MRCoNS carriage rate was less than 14% in I, II and III phase students where as 29.28% in interns. Drug resistance was very high among MRCoNS isolates when compared to methicillin sensitive CoNS(MSCoNS) isolates. All isolates were susceptible to Linezolid. Nasal carriage rate of CoNS and MRCoNS is very high among medical students. Statistically significant high carriage rate of MRCoNS was seen in students exposed to hospital environment and patients. High level and multi drug resistance is seen in most of MRCoNS isolates. Linezolid has good antiCoNS activity. Continuous surveillance, decolonization of carriers and improvement in hygiene standards in hospitals should be adopted to prevent transmission of MRCoNS.