Epidemiology and Antibiogram of Clinical Staphylococcus aureus Isolates from Tertiary Care Hospitals in Dhaka, Bangladesh

This study aimed to investigate the epidemiology and antibiogram of clinical Staphylococcus aureus isolates from three tertiary care hospitals in Dhaka, Bangladesh.

A total of 185 clinical S. aureus isolates were studied from March 2016 to February 2017 and identified by standard microbiological methods, and an antibiogram was determined by disc diffusion method. A duplex polymerase chain reaction (PCR) assay was performed on all isolates to detect femA and mecA genes of S. aureus.

Among the 185 isolates, all (100%) were positive for the femA gene, 76 (41.1%) were methicillinresistant S. aureus (MRSA), and 109 (58.9%) were methicillin-susceptible S. aureus (MSSA). The highest and the lowest frequency of both MRSA were isolated from pus and urine specimens, respectively. All 185 S. aureus were 100% sensitive to both vancomycin and linezolid and were highly sensitive towards rifampicin (94%), meropenem (87%), gentamicin (85.4%), and cotrimoxazole (82.2%), whereas the highest resistance was against penicillin G (94.6%) followed by amoxicillin/clavulanic acid (82.7%), azithromycin (72.4%), amoxicillin (66.5%), and ciprofloxacin (63.2%). After vancomycin and linezolid, MRSA showed good susceptibility to rifampicin, cotrimoxazole, and gentamicin, while MSSA exhibited high sensitivity toward rifampicin, gentamicin, cefoxitin, meropenem, cloxacillin, ceftriaxone, and cotrimoxazole. Furthermore, MRSA was significantly more resistant to antibiotics than MSSA (P value < 0.05), and the majority of S. aureus (81.1%), MRSA (97.4%), and MSSA (69.7%) were multidrug-resistant (MDR).

Our findings can guide physicians to provide effective antibiotic therapy, implement monitoring and control strategies to reduce antimicrobial resistance, and prevent the dissemination of MRSA and MDR in the environment.