SIDS: a bacterial cause?

by Tara Smith     Department: Health & Life Sciences

While disease diagnostics have come a long way in the last century, there still remain many that are "idiopathic"--a way of saying "we don't know what causes this." One of the most common of these idiopathic diseases is Sudden Infant Death Syndrome, aka SIDS. We have discovered over the years a number of risk factors for it--smoking in the house, sleeping with heavy covers and on the stomach, for instance--but we don't know exactly why these contribute to SIDS, and why some infants who don't have these risk factors inexplicably die anyway. New research, however, suggests there may be a bacterial cause for some of these deaths:

Researchers found potentially dangerous bacteria such as Staphylococcus aureus and E. coli in nearly half of all babies who died suddenly and without explanation over a decade at a London hospital. Their findings are in Friday's Lancet medical journal.

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The researchers used autopsy samples from 470 infants who died suddenly and unexpectedly between 1996 and 2005. They found dangerous bacteria in 181 babies, or nearly half of the 365 whose deaths were unexplained. There were similar bacteria in about a quarter (14 of 53) of the babies who died of known causes, excluding those who died of bacterial infections.

Most of the bacteria were detected in the babies' lungs and spleens.

They do note, though, that just because these bacteria were found, it doesn't necessarily make them the cause of death. Even though these species can cause disease, they're carried by many of us without causing any harm. But, the finding of them in the lungs and spleen (rather than places where they typically colonize us, such as the nose, skin, and gut) is interesting, and more suggestive of something pathogenic than just a harmless standby organism. Additional studies, of course, are needed to shed light on this--and even if these are found to be causative, I'm not sure right now what (besides a vaccine, which hasn't been forthcoming for E. coli and Staph) could be done to prevent SIDS with this knowledge.

Tags: E. coli, microbiology, SIDS, Staphylococcus