Molecular epidemiology of systemic infection caused by Enterobacter cloacae in a high-risk neonatal intensive care unit.
OBJECTIVE
To investigate the molecular epidemiology of systemic nosocomial infections caused by Enterobacter cloacae.


METHODS
Neonatal intensive care unit (NICU) of a tertiary-care university hospital.


METHODS
Forty-two high-risk neonates with systemic infections caused by E. cloacae.


METHODS
From 1995 to 1997, the variables associated with death in these patients were evaluated. The molecular epidemiology of the strains responsible for the systemic infections, and 14 unrelated strains, was studied using plasmid analysis and pulsed-field gel electrophoresis (PFGE).


RESULTS
The overall mortality rate for infection caused by E. cloacae was 34%, whereas the crude mortality rate during the study period was 8.12% (P < .001). Gestational age (preterm neonates) and birth weight (small for gestational age) were not associated with a higher risk of death. Insertion of a venous catheter by dissection of a peripheral vein was the only invasive procedure related to death (P = .016) in this study. A molecular analysis showed that three outbreaks, each occurring in a different year, were caused by strains with distinctive DNA profiles. Only one outbreak was identified by the infection control service, in the NICU. Plasmid analysis and PFGE showed similar ability to discriminate control strains from the E. cloacae strains isolated from the neonates.


CONCLUSIONS
Systemic infections caused by E. cloacae in our NICU were associated with a high mortality rate and occurred as small, unrecognized outbreaks. These results may not be generalizable because the data were from a single center.
Kuboyama
Rogerio Hakio
RH
Infectious Diseases Division, Faculty of Medical Sciences, Universidade Estadual de Campinas, São Paulo, Brazil.
de Oliveira
Helenice Bosco
HB
Moretti-Branchini
Maria Luiza
ML
D015373:Bacterial Typing Techniques; D001938:Brazil / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D004269:DNA, Bacterial; D004196:Disease Outbreaks; D004587:Electrophoresis, Agar Gel; D016521:Electrophoresis, Gel, Pulsed-Field; D016972:Enterobacter cloacae / Q000145:classification* / Q000235:genetics*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000401:mortality; D006785:Hospitals, University; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D017720:Molecular Epidemiology
D004269:DNA, Bacterial