Case-control analysis of endemic Serratia marcescens bacteremia in a neonatal intensive care unit
- 1Divisions of Perinatal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- 2Divisions of Infectious Diseases, Yale University School of Medicine, New Haven, Connecticut, USA
- 3Division of Infectious Diseases, Department of Internal Medicine and Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, USA
- Correspondence to:
Patrick G Gallagher
Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, P O Box 208064, New Haven, CT 06520-8064, USA;
- Accepted 23 October 2006
- Revised 4 October 2006
- Published Online First 6 November 2006
Background:Serratia marcescens is an opportunistic gram-negative rod which typically infects compromised hosts.
Objectives: To identify risk factors, signs, and outcomes associated with non-epidemic S marcescens bacteremia in a neonatal intensive care unit (NICU).
Methods: The records of infants with S marcescens bacteremia while in the Yale-New Haven Hospital NICU from 1980–2004 were reviewed. A matched case-control study was performed by comparing each case of S marcescens to 2 uninfected controls and 2 cases of Escherichia coli bacteremia.
Results: Twenty-five sporadic cases of S marcescens bacteremia were identified. Eleven available isolates were determined to be different strains by pulse field gel electrophoresis. Infants with S marcescens bacteremia had median gestational age and birth weight of 28 weeks and 1235 grams, respectively. Compared to matched, uninfected controls, infants with S marcescens bacteremia were more likely to have had a central vascular catheter (OR = 4.33; 95% CI (1.41 to 13.36)) and surgery (OR = 5.67; 95% CI (1.81 to 17.37)), and had a higher overall mortality (44% vs 2%; OR = 38.50; 95% CI (4.57 to 324.47)). Compared to E coli matched controls, infants with S marcescens bacteremia had later onset of infection (median of 33 days of life vs 10; p<0.001), prolonged intubation (OR = 5.76; 95% CI (1.80 to 18.42)), and a higher rate of CVC (OR = 7.77; 95% CI (2.48 to 24.31)) use at the time of infection. A higher rate of meningitis (24% vs 7%; OR = 3.98; 95% CI (1.09 to 14.50)) was observed with S marcescens bacteremia compared to E coli.
Conclusions:S marcescens bacteremia occurs sporadically in the NICU, primarily in premature infants requiring support apparatus late in their hospital course. Associated meningitis is common and mortality high.
- CVC, central vascular catheter
- GNR, gram-negative rod
- NICU, neonatal intensive care unit
- TPN, total parenteral nutrition
- Y-NHH, Yale-New Haven Hospital
Funding: Supported in part by National Institute of Child Health and Human Development Training Grant T32 HD 07094 (M.J.B.).
Competing interests: None.