Salmonella thomson outbreak in a Canadian newborn nursery.

OBJECTIVE

To determine the mode of salmonella transmission during an outbreak in a newborn nursery.

DESIGN

Outbreak investigation with retrospective review of medical, microbiological and work records, active case-finding, and active surveillance. A case was defined as a newborn with salmonella isolated from any site.

SETTING

University affiliated community hospital near Montreal with 125 active care beds and 3000 deliveries annually.

PATIENTS

Cases were identified from the microbiology reports and public health notifications for one month before to six months after detection of the outbreak. All neonates with diarrhea had stool cultures during the period of observation.

RESULTS

Four cases of neonatal salmonella infection were detected. The index infection was acquired at birth from a mother with severe gastroenteritis from contaminated chicken. The first of five secondary cases - three other neonates and two mothers - was only detected 11 days after departure of the index case. Three of the four infants required intensive treatment and one remained a chronic carrier and was rejected for daycare services. No food or health care worker was associated with infection of neonates. The diapering technique had been changed one month earlier because the hospital had stopped purchasing disposable washcloths.

CONCLUSIONS

Three of the four neonatal salmonella infections caused severe morbidity. The organism was easily transmitted when breaks in technique probably allowed contamination of fomites, survival in the inanimate environment, and subsequent cross-infection to other neonates. Simple unexpected changes in the availability of material resources such as washcloths may have adversely influenced clinical practises with a resultant breakdown in infection control procedures.