Study of prevalence and antimicrobial susceptibility of blood culture bacterial isolates

Bloodstream infections are associated with significant morbidity and mortality. Definitive diagnosis is by bacteriologic culture of blood samples to identify organisms and establish antibiotic susceptibility. Between July and September 2009, 249 blood samples collected from patients at the University of Benin Teaching Hospital were processed. Positive cultures which accounted for 48(19.3%) of total samples screened, were purified and identified according to standard methods. Sensitivity of bacteria to different antibiotics was determined by Kirby-Bauer disk diffusion method. Microorganisms recovered were Staphylococcus aureus (14.6%), Providencia spp., Pseudomonas aeruginosa, Enterobacter spp., Klebsiella pneumoniae and Proteus mirabilis (12.5% respectively), Escherichia coli and Staphylococcus epidermidis (8.3% respectively) and Citrobacter freundii (6.3%). The highest antibiotic activities against Gram positive isolates were observed for ofloxacin (90.9%), nitrofurantoin (81.8%) and gentamicin (72.7%), while in Gram negative bacteria, ofloxacin (81.1%) and nalidixic acid (45.9%) were most effective. The possibility of drug resistance acquisition by bacteria makes continuous surveillance of antimicrobial susceptibility patterns of bacteria essential as this will enhance efforts to identify resistance and attempt to limit its spread.