Staphylococcus aureus: Nasal-carriage in Health Care Workers and In-patients with Special Reference to MRSA

Aims: To find out the nasal carriage of Staphylococcus aureus in health care workers and in-patients in a tertiary care center.

Study Design: Cross sectional study.

Place and Duration of Study: Department of Microbiology, Government Medical College and Hospital, Srinagar Kashmir. One year study (July 2013 to June 2014).

Methodology: Nasal swabs were taken from health care workers (HCWs) and in-patients and these were processed for the recovery of Staphylococcus aureus (S. aureus) and methicillin resistant Staphylococcus aureus (MRSA). Antimicrobial susceptibility of the isolates to various antibiotics was performed as per Clinical Laboratory Standards Institute (CLSI), guidelines and D-test done to ascertain constitutive macrolide-lincosamide-streptogramin B (cMLSB) and inducible macrolide-lincosamide-streptogramin B (iMLSB) phenotype. Risk factors for their carriage were also analyzed. Statistical analysis was done using SPSS software version 16 and a P value of < 0.05 was taken as significant.

Results: Higher rate of isolation of S. aureus and MRSA was seen among 480 in-patients (47.1% and 32.7% respectively) compared with 256 HCWs (32.8% and 19.1% respectively). Significant resistance (P<0.05) to clindamycin, erythromycin, ciprofloxacin, tetracycline and co-trimoxazole was seen in MRSA isolates recovered from in-patients. MRSA isolates had higher cMLSB and iMLSB resistance. Years of service and level of education in HCWs were significantly associated with MRSA carriage in them.

Conclusion: Nasal-carriage of S. aureus and MRSA is common in HCWs and in-patients in our hospital. Apart from periodic screening for MRSA carriage, strict adherence to existing infection control guidelines is mandatory.