There is now more reason than ever to link common bacteria to sudden infant death syndrome (SIDS) or crib death.
The link was proposed decades ago, but evidence was scarce.
Now researchers from the Great Ormond Street Hospital for Children in London, who trawled through the results of about 500 autopsies, have shown that Staphylococcus aureus and Escherichia coli are more prevalent in SIDS babies than in those whose cause of death was known.
Bacteria are unlikely to be solely to blame, but the body's immune response to bacterial toxins may help explain how several known environmental and genetic risk factors for SIDS might become fatal.
Sleeping on the front increases bacteria in the baby's upper windpipe, smoking during pregnancy alters the fetal immune response, and some genetic differences in SIDS babies relate to immune response.