Nosocomial transmission of group B streptococci proven by positive environmental culture.

Abstract

Neonates usually acquire Group B streptococcal infection vertically from the maternal birth canal during delivery. In January 2010, a Group B streptococcal outbreak investigation was conducted in response to an increased number of clinical specimens from our neonatal intensive care unit. Microbiology laboratory records were reviewed to identify Group B streptococcal from specimens originating from the neonatal intensive care unit during December 2009 and January 2010. Patients from whom these specimens were collected were identified and their charts reviewed. Environmental samples to screen for Group B streptococcal were collected from the unit, clinical and environmental isolates were compared by pulsed field gel electrophoresis. Point prevalence screening was conducted twice before declaring the outbreak over. Pulsed field gel electrophoresis patterns of three clinical strains from six patients were indistinguishable. One environmental strain was isolated from one of the patients monitor, and had identical pulsed field gel electrophoresis pattern to that of the three clinical strains. Infection control measures were implemented in the neonatal intensive care unit and follow-up point prevalence screening identified no new cases. Although poor infection control practice has been implicated in previous reports of nosocomial outbreaks of Group B streptococcal infection in neonatal intensive care units, our finding provides unique evidence that the environment can act as a reservoir of Group B streptococcal and play a key role in nosocomial transmission.