Patterns of isolation of common gram positive bacterial pathogens and their susceptibilities to antimicrobial agents in Jimma Hospital

Gram positive bacteria are frequently emerging as antibiotic resistant pathogens, causing serious infections than ever before in the ill and debilitated patients. The pattern of isolation and the antimicrobial susceptibilities of common Gram positive cocci including Staphylococcus aureus, coagulase negative staphylococcus (CoNS), Streptococcus pyogenes, Enterococcus species and Streptococcus pneumoniae was investigated between January 1997 and June 2000 in Jimma Hospital. Of the 500 specimens collected from children and adults, 116 (23.2%) consisted of one or more of the above organisms. The following strains: Staphylococcus aureus, 47(40.5%), CONS, 36; (31.0%), Streptococcus pneumoniae, 26 (22.4%) Streptococcus pyogenes, 5 (4.3%) and Streptococcus faecalis, 2(1.7%) were isolated from different specimens including pus, sputum, urine, stool, blood and oro/nasopharyngeal swabs of patients. The in vitro activities of 14 different antibiotics including penicillin G, ampicillin, cloxacillin, cephalothin, gentamicin, kanamycin, tetracycline, chloramphenicol, erythromycin, trimethoprim-sulfamethoxazole, streptomycin, methicillin, vancomycin and clindamycin was determined against the clinical bacterial isolates. The antimicrobial activities were evaluated by agar diffusion technique using Mueller-Hinton agar according to NCCLS recommendations.,The majority of the pathogens, 59(50.9%) were recovered from upper respiratory tract infections and 17 (14.6%) from the lower respiratory tract. The resistance patterns of S. aureus,CoNS, S. pneumoniae and. enterococci to penicillin was 91.5%, 94.4%, 7.7% and 100% respectively. Penicillin, ampicillin and cloxacillin showed low effects (<60%) on both S. aureus and CONS Multi-drug resistance was observed in all the gram positive isolates, especially higher in staphylococcus species. All isolates of S. aureus (100%) were susceptible to vancomycin, clindamycin and gentamicin. In order to reduce morbidity:,and mortality due to antibiotic resistance susceptibility testing should be performed for the proper management of bacterial infections. This entails the need for national surveillance to monitor antibiotic resistance-in bacteria by susceptibility testing using reliable methods.