[Study of septicemia due to Enterobacter cloacae in a neonatal intensive care unit]

A study was made of Enterobacter cloacae septicemia in 15 newborns in the neonatal intensive care unit (NICU) of the Asahikawa Kosei Hospital from April, 1979 to March, 1996. Their gestational age was 29.7 +/- 4.5 (mean +/- SD) weeks and their birth weight was 1,270 +/- 562 g. The age at the onset of septicemia was 10.3 +/- 7.2 days. Four infants died and the mortality was 26.7%. These infants died within 72 hours after onset of septicemia. Thrombocytopenia (< 50,000/microliter) in the patients who died was significantly more than in the patients who improved (p < 0.05). Antibiotic susceptibilities were determined by the Kirby-Bauer method. Three E. cloacae strains isolated in 1982 were sensitive to ampicillin (ABPC) and cefotaxime (CTX), 4 strains between 1983 and 1984 were resistant to ABPC and were sensitive to CTX, 5 strains between 1985 and 1992 were resistant to ABPC and CTX, and 3 strains between 1993 and 1995 were resistant to ABPC and were sensitive to CTX. These results suggested that the emergence of resistant E. cloacae was related to the use of corresponding antibiotics. Our observations showed that E. cloacae was one of the potential pathogens seen in nosocomial infections which is becoming progressively common in newborns and routine bacteriological surveillance is very important in the NICU.