Antimicrobial Susceptibility Patterns of Methicillin-Resistant Staphylococcus aureus Isolates Collected from Healthcare and Community Facilities in Libya Show a High Level of Resistance to Fusidic Acid

Wareg SE, Foster HA and Daw MA

Abstract

Staphylococcus aureus is an important human pathogen and is implicated in a wide variety of infections in the healthcare and community settings. The organism is often subcategorized as community-associated MRSA (CAMRSA) or health care-associated MRSA (HA-MRSA). Five hundred and eleven S. aureus strains were isolated from clinical specimens submitted to the microbiology laboratories at Tripoli Central Hospital, Tripoli Trauma/ Accident Hospital, Tripoli Medical Centre and Tripoli Burn Hospital between October 2009 and November 2010. MRSA was detected using cefoxitin (30 μg) disc and antibiotic susceptibility pattern was determined using the Kirby and Bauer disc diffusion susceptibility testing method and confirmed for fusidic acid and vancomycin by determination of minimum inhibitory concentration The prevalence of Inpatient Healthcare Associated MRSA (IP-MRSA), outpatient-Healthcare Associated MRSA (OP-MRSA) and community carried MRSA (CC-MRSA) was 43%, 37% and 34% respectively. The isolates of MRSA displayed resistance to fusidic acid and multiple drug resistance (MDR) to 2-9 antibiotics for IP-MRSA, 2-7 antibiotics for OP-MRSA and 2-6 antibiotics for CC-MRSA. The most frequent MDR was resistance to fusidic acid, ciprofloxacin, streptomycin and clindamycin. This study has shown that MRSA is prevalent with similar rates for IP-MRSA, OP-MRSA and CC-MRSA strains. Lack of controls on supply of antibiotics may be responsible for the fusidic acid resistance.

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