Airborne methicillin-resistant Staphylococcus aureus in the indoor environment of King Abdullah University Hospital,Jordan

Methicillin-resistant Staphylococcus aureus (MRSA) is seen with increasing frequency in hospitals and is considered as a major cause of hospital-acquired infection. The objectives of this study were to isolate and characterize the airborne MRSA in different wards of a referral university hospital. Thirty-four air samples of 100 litres volume/min were collected by a microbiological air sampler, then impacted on trypticase soy agar (TSA) and incubated at 37℃ for 48 h. Recovered colonies were identified by standard methods. From all S. aureus, 9.3% was identified as MRSA which comprised 4.2%, 3.1% and 2% in the adult and nursery intensive care units, and operating theatres (ICU, NICU and OT, respectively). MRSA isolates were remarkably susceptible (87.1%) to each of amikacin, chloramphenicol, imipenem and rifampin. MRSA isolates were shown in all units with minimum inhibitory concentration value of >256, 32 and 6 µg/l in ICU, OT and NICU, respectively. Polymerase chain reaction analysis of all MRSA isolates indicated the amplification of the mec A gene. It is concluded that MRSA was isolated from all units making eradication of MRSA a target hard to achieve. However, the antibiotic resistance profile of the MRSA isolates looks promising leaving a room to combat nosocomial infections.