Comparative prevalence of MRSA in two Nepalese tertiary care hospitals

This comparative study has been focused on the prevalence of MRSA types and their antibiotic resistance in two tertiary care hospitals of Nepal. During November 2007 to June 2009, clinical samples from patients with nosocomial infection from two Nepali hospitals, Kathmandu Based Hospital (KBH) and Lalitpur Based Hospital (LBH) were cultured and antibiotic susceptibility tests done following standard methodology in Microbiology laboratory, Tribhuvan University Teaching Hospital, Kathmandu, Nepal. Occurrence of MRSA (52.9% of 304 Staphylococcus aureus isolates) in KBH and that of MSSA (62% of 100 S. aureus isolates) in LBH were significant. No association of age was observed with MRSA or MSSA. Among MSSA from both hospitals, the highest resistance was found against penicillin. KBH urinary isolates were resistant to norfloxacin (51.4%), while isolates from other sites were resistant to ciprofloxacin (30.6%), erythromycin (12%), gentamicin (10.3%). LBH isolates were resistant to co-trimoxazole (22.6%), erythromycin (17.2%), ciprofloxacin (13.8%), gentamicin (12.9%). Among MRSA, most of the isolates from both hospitals were resistant to a wide array of antibiotics. A majority of the MSSA and MRSA isolates were susceptible to rifampicin and chloramphenicol. Most of KBH MRSA were homogeneous MRSA, 80.5% (significant), of which, 99.2% were multiresistant oxacillin resistant S. aureus (MORSA). And among the heterogeneous MRSA isolates from KBH, 71% were MORSA. On the other hand, among LBH MRSA isolates, 52.6% were homogeneous MRSA, cent percent of which were MORSA while 47.4% were heterogeneous MRSA of which 44.5% were MORSA. Since almost all of the homogeneous MRSA and most of the heterogeneous MRSA from both hospitals were MORSA, there is a possibility that a hospital acquired S. aureus could be MORSA. Hence, every infected patient should be considered as a potential source of MORSA.