Prevalence and antibiotic susceptibility pattern of bacterial isolates from blood culture in Tikur Anbassa Hospital, Addis Ababa, Ethiopia

Between Mid-1996 and Mid-1998, 238 bacteria strains isolated from blood cul ture of adult patients of Tikur Anbassa Hospital, Addis Ababa, Ethiopia, we re retrospectively analyzed for their frequency of isolation and antibiotic susceptibility pattern. Coagulase negative Staphylococcus aureus (CNS) wer e isolated with the highest frequency 103 (43.3%), followed by Staphylococc us aureus 34(14.3%), Klebsiella spp.23(9.7%), E.Coli 19(8.1%), Pseudomonas spp.16(6.7%), Acinetobacter spp.12(5%), Salmonella spp.9(3.8%) and miscella neous group 22(9.2%). The grain positive bacteria constituted 149(62.6%) of the total blood isolates. It is suggested that a proportion of both the gr am positive and grain negative isolated represent contaminants at blood sam pling. Rates of susceptibility for gram positive range from 12% to 76%, and for gram negatives range from 8% to 46%. In general, rates of susceptibili ties to all antibiotics tested for gram negatives were very low as compared to gram positives. Among the gram positives, more than half of the isolate s were sensitive to amoxicillin + clavulanic acid, ampicillin, carbenicilli n, cephalothin, chloramphenicol, erythromycin and methicillin. Gram negativ e bacteria showed a high rate of resistance to many of the commonly prescri bed antimicrobial drugs: amoxicillin + clavulanic acid (65%), ampicillin (8 7.5%), amoxicillin (91.7%), carbenicillin (75%), cephalothin (73.6%), chlor amphenicol (65%), gentamicin (55.6%), kanamycin (54%), trimethoprim-sulpham ethoxazole (64%) and tetracycline (61 %). If generally considered, only gen tamicin and kanamycin were relatively effective against gram negatives. Ove r 85% Salmonella spp were sensitive to chloramphenicol and trimethoprimsulp hamethoxazole. Compared to previous studies done in the same hospital, ther e is a higher rate of antibiotic resistance for most types of blood culture isolates particularly for gram negatives. The rational use of drugs should be practiced in order to minimize the spread of drug resistant bacteria.