Enterobacter sakazakii (E. sakazakii) invasive disease became notifiable on 21 July 2005.
Notification enables both identification of instances of invasive disease, and consideration of the need for public health action. This includes consideration of risk factors including use of powdered infant formula and the time between making up the formula feed and infant feeding, and microbiological assessments.
Report into action of sector agencies
Notification of E. sakazakii was a recommendation of a report into the investigation of the death of a premature infant who had contracted the disease in 2004. The report is Inquiry into Actions of Sector Agencies in Relation to Contamination of Infant Formula with Enterobacter Sakazakii [Find it in the Ministry's Library Catalogue].
Another result of the report was that district health boards were asked to institute voluntary laboratory reporting to the Institute of Environmental Science & Research (ESR) in instances of isolation of E. sakazakii.
E. sakazakii is an emerging health risk
There is increasing international concern about E. sakazakii as a rare cause of severe disease in premature infants. There have been about 50 cases of infections with this gram-negative bacterium reported in the literature worldwide over the last 40 years. In New Zealand, there have been four identified cases of infection in premature babies (one in 1986, two in 1991, and one in 2004).
While E. sakazakii has caused disease in all age groups, most disease has been reported in infants less then two months old. Neonates in hospital settings have the highest risk, especially if pre-term, low-birth-weight or immunocompromised. Infants of HIV-positive mothers are also at risk.
The organism can cause meningtitis, brain abscesses, necrotising enterocolitis, bloody diarrhoea, and sepsis. Illness is often severe and life threatening, with significant long-term sequelae in those who recover.
The bacterium is found in the environment and may also be present in powdered infant formula at low levels. Powdered infant formula is not a sterile product, and low-level contamination is not limited to any particular product brand.
Advice regarding infant feeding
In neonatal intensive care settings, powdered infant formula is no longer used unless there is no alternative available. If breastfeeding is not possible, then (sterile, liquid) ready-to-feed infant formula is used.
Guidance for preparing infant formula in the community now includes the following: when preparing powdered infant formula prepare only the amount needed for baby’s next feed, so that it can be prepared as close as possible to the feeding time.
Further advice on preparation of powdered infant formula can be found on the New Zealand Food Safety Authority website.