Scope of urinary pathogens isolated in the public health bacteriology laboratory, Harare: Antibiotic susceptibility patterns of isolates and incidence of haemolytic bacteria

Objectives: To determine the scope of urinary pathogens isolated in the Public Health Bacteriology Laboratory, their antibiotic susceptibility patterns and the incidence of haemolytic bacteria in Harare. Design: Prospective study. Patients of different age groups attending various clinics in Parirenyatwa Hospital, Harare, between October 1995 and April 1996 were enrolled for the study. Setting: A laboratory based study at the Bacteriology Unit, Public Health Laboratories, Harare. Subjects: 1 760 urine specimens obtained from male and female patients suspected of having UTI. Results: Out of a total number of 1 760 urine specimens screened only 473 (26,9pc) were positive for UTI pathogens. Four hundred and nineteen (88,5pc) and 46 (9,7pc) of the 473 positive UTI pathogens were Gram negative and Gram positive bacteria respectively. Eight (1,7pc) of the positive isolates were Candida spp. The commonest pathogen isolated was Escherichia coli (40,5pc), followed by Klebsiella spp. (22,1pc) and Proteus spp. (7,2pc). Of the positive isolates 184 (38,9pc) and seven (1,5pc) were β- and α-haemolytic respectively. Of E. coli isolates 72pc were β-haemolytic. Sex distribution showed that 53pc and 47pc of the UTI pathogens were isolated from males and females respectively. E. coli was more predominant in females (51,3pc). Antibiotic susceptibility patterns revealed that 100pc of strains of E. coli, Proteus spp., Serratia spp., Salmonella spp., Morganella spp., Staphylococcus aureus and coagulase negative staphylococci (CNS) were sensitive to Ciprofloxacin. Urinary isolates were markedly resistant to Tetracycline, Carbenicillin, Cotrimoxazole, Ampicillin and Nitrofurantoin. Fusidic acid and Clindamycin were active against staphylococcal species. Conclusion : We conclude that E. coli is the commonest UTI pathogen and that 72pc of strains were β-haemolytic. We suggest the use of Ciprofloxacin as the drug of choice for the treatment of UTI caused by both Gram positive and Gram negative UTI pathogens. Nitrofurantoin and Gentamycin are in addition recommended for E. coli while Fusidic acid and Clindamycin may be useful for staphylococcal species.