OUTBREAK OF ACINETOBACTER SPP. BLOOD-STREAM INFECTIONS IN A NURSERY ASSOCIATED WITH CONTAMINATED AEROSOLS AND AIR-CONDITIONERS

Background. Acinetobacter spp. are multidrug-resistant bacteria that g row well in water and cause infections with unexplained, increased sum mer prevalence. In August, 1996, eight infants acquired Acinetobacter spp. bloodstream infection (A-BSI) while in a nursery in the Bahamas; three infants died and an investigation was initiated. Methods. A case patient was defined as any newborn in the nursery during August 6 to 13, 1996, with A-BSI. To identify risk factors for A-BSI we conducted a retrospective cohort study and performed environmental cultures and air sampling using settle plates. The genetic relatedness of environme ntal isolates was assessed by pulsed field gel electrophoresis. Result s. Of 33 patients in the nursery 8 (24%) met the case definition. Pati ents with peripheral iv catheters were more likely to develop A-BSI (8 of 21 vs. 0 of 10, P < 0.05). Multivariate analysis among patients wi th iv catheters indicated that only exposure to one nurse was an indep endent risk factor for developing A-BSI (P < 0.005). Nursery settle pl ates were more likely to grow Acinetobacter spp. than were settle plat es from other hospital areas (8 of 9 vs. 0 of 5, P < 0.005); cultures from nursery air conditioners also grew Acinetobacter spp. Environment al isolates were genetically diverse. After installation of a new air conditioner in May, 1995, A-BSIs occurred more frequently during month s of increased absolute humidity or environmental dew point. Conclusio ns. Acinetobacter spp. may cause nosocomial BSI and death among infant s during periods of polyclonal airborne dissemination; breaks in asept ic technique during: iv medication.