Science - January 8, 2004

Dangerous bacteria for babies seems to be lurking everywhere

Young babies infected with the bacteria Enterobacter sakazakii have an eighty percent chance of dying. Until recently little was known about how widespread the occurrence of this pathogen is, but Wageningen researchers have discovered that it is present almost everywhere.

“The number of children that actually become ill from Enterobacter sakazakii is very small,” says Dr Martine Reij, of the Laboratory of Food Microbiology at Wageningen University. “A total of sixty cases worldwide have been described in the literature. Some are adults in hospitals with serious wounds, but it seems to be newborn or premature babies who are most likely to fall ill. The symptoms are also serious, and may include meningitis and perforations in the digestive tract. Healthy adults have nothing to fear from the organism.”

Researchers have found the bacteria in powdered milk formula used for baby feed. The pathogen is apparently capable of surviving the production process, which includes high temperatures and desiccation. But the question is whether the powdered milk formula is the only channel through which the pathogen reaches babies. International infant-feed manufacturer Nestlé financed Wageningen researchers to find out more. The scientists took samples from the households of family and friends, and also from food factories. “What we ended up doing was using vacuum cleaners to collect as much dust as possible, and then we analysed the dust for traces of the bacteria,” explains Reij. “We had to develop new methods to trace the bacteria in vacuum cleaner bags.”

The research results were published in The Lancet of 3 January 2004. “We found the bacteria everywhere,” continues Reij. “A third of the samples of household dust contained the Enterobacter. We visited four factories that produce infant formula feed, and found the bacteria at all of them.” The researchers also detected the bacteria in factories that produce breakfast cereals, chocolate and pasta.

Reij believes that because the Enterobacter is found everywhere, the most important line of defence is the user. “Babies in incubators in hospitals are hooked up to a continuous drip for their food. The sac containing the feed must not be allowed to hang for too long. In this way it is possible to prevent Enterobacter contamination growing to dangerous concentrations. It is also probably not a good idea for parents to make up a large supply of bottle feed for the whole day at once, and then keep it in the refrigerator.”

The editorial board of The Lancet found the article important enough to ask the Canadian microbiologist Jeffrey Farber to write a commentary. The first author of the article is AIO Chantal Kandhi, who has been conducting PhD research since 2002 on Enterobacter sakazakii. Her research is sponsored by Nestlé.

Willem Koert