EPIDEMIC GRAM-NEGATIVE BACTEREMIA IN A NEONATAL INTENSIVE-CARE UNIT IN GUATEMALA

Background. Nosocomial bloodstream infection is an important cause of morbidity and mortality among neonates. From September 1 through Decem ber 5, 1990 (epidemic period), gram-negative bacteremia developed in 2 6 neonates after their admission to the neonatal intensive care unit ( NICU) of Hospital General, a 1000-bed public teaching hospital in Guat emala with a 16-bed NICU. Twenty-three of the 26 patients (88%) died. Methods: To determine risk factors for and modes of transmission of gr am-negative bacteremia in the NICU, we conducted a cohort study of NIC U patients who had at least one blood culture drawn at least 24 hours after admission to the NICU and performed a microbiologic investigatio n in the NICU. Results: The rate of gram-negative bacteremia was signi ficantly higher among patients born at Hospital General, delivered by cesarian section, and exposed to selected intravenous medications and invasive procedures in the NICU during the 3 days before the referent blood culture was obtained. During the epidemic period, the hospital's chlorinated well-water system malfunctioned; chlorine levels were und etectable and tap water samples contained elevated microbial levels, i ncluding total and fecal coliform bacteria. Serratia marcescens was id entified in 81 % of case-patient blood cultures (13/16) available for testing and from 57% of NICU personnel handwashings (4/7). Most S. mar cescens blood isolates were serotype O3:H12 (46%) or O14:H12 (31 %) an d were resistant to ampicillin (100%) and gentamicin (77%), the antimi crobials used routinely in the NICU. Conclusions: We hypothesize that gram-negative bacteremia occurred after invasive procedures were perfo rmed on neonates whose skin became colonized through bathing or from h ands of NICU personnel.