Aerobic bacteria isolated from blood cultures of patients and their antibiotic susceptibilities in Harare, Zimbabwe

C. L. Obi*, E. Mazarura

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Objective: To assess the extent of involvement of different types of gram positive and gram negative bacteria and incidence of monomicrobial and polymicrobial cases in patients with bacteremia but without a record of the underlying clinical conditions of the patients. Antibiotic susceptibility patterns of isolates were also determined to guide clinicians in the management of such bacteremic cases especially where routine sensitivity testing is not performed. Design: Case series. Setting: The study comprised patients attending different clinics in Parirenyatwa Hospital, Harare. Subjects: A total of 817 blood cultures from patients, comprising 469 and 348 males and females respectively. There were no records of the underlying clinical conditions of the patients. Main outcome measures: Prevalence rates of organisms and their antibiograms using standard techniques and Kirby-Bauer disc diffusion method. Results: Results obtained revealed that only 303 (37.1%) of the 817 total samples screened were positive for either monomicrobial or polymicrobial bacteremia. Two hundred and eighteen (71.9%) and 85 of positive cultures were Gram positive and Gram negative bacteria respectively. Coagulase negative staphylococci (CNS) strains were the predominant organisms isolated (42.9%). Other organisms isolated were Staphylococcus aureus (11.6%), Escherichia coli (6.9%), Salmonella spp. (8.3%), Klebsiella spp. (5.3%), whereas Pseudomonas aeruginosa, Haemophilus influenzae, Enterobacter and Micrococcus species each accounted for less than 4%. Antibiogram patterns showed multiple resistance of S. aureus and CNS to Penicillin, Erythromycin and Methicillin. All isolates of S. pyogenes (10), S. pneumoniae (18) and Micrococcus spp (10), were susceptible to penicillin. Ciprofloxacin, Clindamycin, Fusidic acid and Gentamycin were highly active against gram positive organisms except that Gentamycin was inactive against S. pneumoniae. Ceforoxime, Erythromycin and Ceftriazone also showed good activities against Gram positive organisms. All (10) isolates of P. aeruginosa were susceptible to Polymyxin B, Carbenicillin and Ciprofloxacin. Ciprofloxacin, Norfloxacin and Gentamycin were highly active against all Gram negative bacteria. Conclusion: For infections due to both Gram positive and Gram negative bacteria, Ciprofloxacin and Gentamycin would be appropriate for therapy whereas Fusidic acid and Clindamycin may, in addition, be recommended for Gram positive organisms. It is also concluded that a prevalence rate of 37.1% of bacteremic cases existed in the sampled population and that monomicrobial cases were more predominant.

Original languageEnglish
Pages (from-to)332-336
Number of pages5
JournalCentral African Journal of Medicine
Issue number12
Publication statusPublished - 1996
Externally publishedYes


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