Risk factors and etiology of neonatal sepsis in Tikur Anbessa University Hospital, Ethiopia.

Background: Neonatal sepsis is one of the most common reasons for admission to neonatal units in developing countries. It is also a major cause of mortality in both developed and developing countries.
Objectives: This study was undertaken to determine bacterial etiologies of neonatal and to assess their susceptibility pattern. An attempt has been also made to identify the possible maternal and neonatal risk factors responsible for neonatal septicemia.
Methods: Blood samples were collected for culture from newborn babies (n=302, age: 0-28 days) with a clinical diagnosis of neonatal sepsis. The sample size was calculated by taking prevalence of culture proven neonatal sepsis in previous Ethiopian study. Antimicrobial susceptibility testing was performed for all blood culture isolates according to the criteria of the National Committee for Clinical Laboratory Standards by disk diffusion method.
Results: Out of the 302 neonates, 55.0% were preterm and 60.0% had low birth weight. The most prevalent clinical features of sepsis were hypothermia (84.8%), respiratory distress (72.8%), failure to feed (71.5%) and lethargy (30.1%). Of the 302 sepsis cases investigated, 135 (44.7%) were positive for blood culture. The most common isolated organisms were Klebsiella spp. (39.2%) and Staphylococcus aureus (22.2%). Neonatal risk factors such as prematurity, low birth weight, abnormal WBC count (high and low) and I:T ratio > or = 0.2 were strongly associated with culture proven neonatal sepsis. No maternal risk factors were identified. Gram positive bacteria were susceptible to most antimicrobial agents tested. On the other hand gram-negative bacteria showed high-level resistance to ampicillin, cefiriaxone, cephalothin, chloramphenicol, and gentamicin. Multiple resistance (resistance to two or more drugs) was observed in 45.7% and 84.2% gram positive and gram negative bacteria respectively (p < 0.05).
Conclusion: Klebsiella spp. and S. aureus were the most common organisms causing neonatal sepsis. Prematurity, low birth weight, abnormal WBC counts and I:T ratio > or = 0.2 were strongly associated with blood culture proven neonatal sepsis. Ciprofloxacin was the most effective drug against the gram-positive and gram-negative bacteria. Routine bacterial surveillance and the study of their resistance patterns must be an essential component of neonatal care. A knowledge of these patterns is essential when local polices on the uses of antibiotics are being devised.