Neonatal septicaemia in Ilorin: bacterial pathogens and antibiotic sensitivity pattern

All cases of septicemia among neonates admitted to the neonatal intensive care unit of the University of Ilorin Teaching Hospital, Ilorin, Nigeria between Jan 1995 and Dec 1996 were studied. Our aims were (1) to assess the incidence and microbial epidemiology of neonatal sepsis, (2) to generate baseline data and necessary research question for a proposed study on predictors of neonatal sepsis in our centre. Microbiology records of patients with confirmed septicemia was reviewed. Each of these babies had a single venous blood sample from a peripheral vein taken under aseptic conditions and before commencement of antibiotics. The needed data were entered into a proforma. Of the 198 neonates screened for sepsis, there were 61 (30.8%) positive blood cultures. Twenty-nine (48%) of these were inborn. The total number of live births in the hospital during the study period was 4118, thus giving a hospital-based incidence of neonatal sepsis of 7.04/1000 for in-born patients. The male:female ratio was 1.2:1. Overall Staphylococcus aureus was the commonest pathogen, accounting for 18 (29.5%) of the total isolates. Other pathogens were as follows; coagulase negative Saphylococcus albus 15 (24.6%), Klebsiella spp 10 (16.4%) and unclassified Coliforms 9 (14.8%). The predominant organisms in the first 48 hours were Gram negative bacilli; accounting for (70%) of the 10 isolates. Between 3 and 7 days of life the Gram positive cocci accounted for 12 (60%) of the 20 isolates while the Gram negative bacilli represented 40%. After 7 days, the predominant organism was Staphylococcus aureus (38.8%) while coagulase-negative Staphylococci were isolated in 7 of 31 isolates (22.6%). The sensitivity pattern showed that 94% of the organisms were sensitive to azythromicin, 77.8% to streptomycin, 73.3% to gentamicin and 69.2% to ampicillin-sulbactam. For the cephalosporins the isolates showed a sensitivity rate of 69% to ceftriaxone, 66.7% to ceftazidime and 58.3% to cefuroxime. As a group the Gram positive organisms had 100% sensitivity to Azythromcin, 85% to ampicillin-sulbactam, 63% to ceftazidime and 62.5% to gentamicin. In the Gram negative group, the best overall sensitivity was to ceftriaxone (86.4%). Gentamicin had 85.7% while sensitivity to ceftazidime was 60%. The distribution of the organisms causing early and late onset sepsis were different. For early onset sepsis, the Gram negative bacilli as a group were the commonest organisms while Staphylococcus aureus was the commonest cause of late onset sepsis. There was a lower incidence of sepsis compared to reports from other parts of the country. This, in addition to differences in antibiotic sensitivity pattern call for more multi-centre studies on predictors of neonatal sepsis. The antibiotic sensitivity profiles suggest that the initial empirical choice of ampicillin-sulbactam and gentamicin appears to be the most rational for our environment.