Abstract
Background: Nosocomial infections are the hospital acquired infections which are leading cause of mortality and disability among patients admitted in hospitals. Microorganism colonization on stethoscope’s diaphragm is the main cause of disease spread. Stethoscopes are well known medical equipment fomites for Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA). In Pakistan and India nosocomial bacterial infections, methicillin-resistant Staphylococcus aureus (MRSA) has much higher prevalence as compared to Northern Europe. Moreover, in Pakistan, the prevalence rate of MRSA is estimated as 35-45 %.
Objective: To determine the frequency of Staphylococcus aureus present on diaphragms of stethoscopes in a tertiary care hospital, Islamabad.
Methodology: The descriptive cross-sectional study was performed at tertiary care hospital in Islamabad. consecutive non-probability sampling technique was used and total sample size of 76 stethoscopes was calculated. Microbial samples were taken by rubbing on whole diaphragm of stethoscope. Later, the sample was incubated with a suitable growth medium for 48-72 hours at 36-37 0C temperature. Staphylococcus aureus appeared and these isolates were placed on agar plates with pre-impregnated antibiotics in different zones and incubated overnight and bacterial growth was observed. The species of staph. aureus which showed resistance to penicillin’s and cephalosporin were known as methicillin-resistant Staphylococcus aureus (MRSA).
Conclusion : Staphylococcus aureus and MRSA related nosocomial infections are one of the common cause of prolong stay of patients in the hospitals. Contaminated stethoscope in hospital settings can transmit Staphylococcus aureus and MRSA in patients. Proper and frequent disinfection of stethoscopes prevents the cross infection of Staphylococcus aureus and MRSA.

Key words: nosocomial infections, Staphylococcus aureus,methicillin-resistant staphylococcus aureus, MRSA, stethoscopes