EPIDEMIOLOGY OF PSEUDOMONAS-AERUGINOSA INFECTIONS IN A NEONATAL INTENSIVE-CARE UNIT

During the 19-month study period, 48 (2 per cent) of the 2177 neonates admitted to the neonatal intensive care unit (NICU) yielded Pseudomonas aeruginosa growths in blood cultures. All these neonates had clinical and haematological evidences of sepsis. Prominent clinical features included sclerema, violaceus necrotic patches, necrotizing enterocolitis (NEC), conjugated hyperbilirubinaemia, and DIC. Over all mortality was 23 per cent, distinctly higher in premature neonates with RDS. The mean gestational age and birth weights (+/- SD) of these neonates were 36.42 (+/- 2.73) weeks and 2173.34 (+/- 567.33) g, respectively. Approximately half of the total cases had low birth weight. Other adverse perinatal events before the development of sepsis included birth asphyxia (60 per cent), neonatal resuscitation (67 per cent), meconium aspiration syndrome (29 per cent), hyaline membrane disease (8 per cent), prolonged hospitalization (44 per cent), closed incubator care (17 per cent), prolonged intravenous fluids (42 per cent), repeated blood sampling (63 per cent), and umbilical catheterization (4 per cent). Analysis of the trend of Pseudomonas sepsis in our NICU revealed six definite outbreaks (more than two cases) interspersed with occasional (one or two) cases. Six study months, however, remained free of Pseudomonas sepsis. Index case was demonstrable on seven occasions. Bacteriological surveillance of the NICU after onset of initial case/cases revealed statistically significant colonization of resuscitation equipment, baby placement sites, and various cleansing solutions by the same bacterial species (P < 0.05). It is possible that Pseudomonas was introduced to our NICU from transfer admissions from other hospitals since on four occasions index case was the one transferred from outside. Measures such as closing the nursery (if more than two cases), cohorting (more than one case), strict hand washing, and removal of contaminated NICU equipment and cleansing solutions limited the spread of infection to only 0-8 of the 25-30 babies admitted.