Salmonella typhimurium phage type 170 in a tertiary paediatric hospital with person-to-person transmission implicated.

Nosocomially-acquired salmonellosis is uncommonly reported in Australia. We report a cluster of gastroenteritis caused by Salmonella Typhimurium phage type 170 (STm 170) centred on a tertiary paediatric hospital in Sydney, New South Wales from 8 to 19 May 2004. A total of 12 children had STm 170 isolated from faecal specimens. Of the 12 cases, seven were acquired in hospital and five in the community. The mean age of the cases was 4.1 years (range: 2 months to 11.2 years). We conducted a case series investigation to generate hypotheses regarding the cause of this outbreak. Standardised interviews with cases' parents were conducted to identify potential exposures including in recently consumed food. An environmental investigation mapped the food preparation and storage areas, movements of staff caring for cases, relative case-bed locations, and duration of stay in these locations. Five of the seven hospital-acquired cases were immunocompromised with a history of prolonged and/or multiple hospital admissions. We found that STm 170 was probably brought into the hospital by a community-acquired case and spread to other in-patients through person-to-person transmission by hospital staff and/or patients. This study emphasises the importance of stringent compliance with hospital infection control practices at all times.