BABY vomit soaking into foam mattresses might help explain some cot deaths. Bacteria linked to sudden infant death syndrome (SIDS) seem to thrive in vomit-soaked polyurethane foam, especially if the babies drink formula rather than breast milk.
Experiments at De Montfort University in Leicester also showed that if the mattress is disturbed or pressed to mimic a baby鈥檚 movements, enough bacteria can rise into the air to cause life-threatening throat infections.
鈥淚f the bacteria get into the throat, they colonise the respiratory tract,鈥� says Richard Sherburn. Once established, the bacteria warm up and can produce 鈥渟upertoxins鈥� that trigger the immune system into abnormally severe assaults. When a baby鈥檚 evolving immune system overreacts, the infant can die of anaphylactic shock.
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Sherburn and his teammate Richard Jenkins found the effect only in 鈥渘on-integral鈥� mattresses made of polyurethane foam. PVC plastic covers two-thirds of these mattresses, but the final third supporting the baby鈥檚 head is covered with a plastic mesh.
After use, these mattresses can be heavily contaminated with bugs, Sherburn told a meeting of the Society for General Microbiology in Warwick last week. The dominant species in the mattresses was Staphylococcus aureus, a bug often found in the throats of SIDS babies. And bacterial levels were 100-fold higher if the baby had vomited formula rather than breast milk.
Echoing earlier research findings, Sherburn confirmed that the abundance of S. aureus rose with the number of babies that had used the mattress. Other bacteria that thrive on vomit as well as urine included Bordetella pertussis, which causes whooping cough, plus Clostridium perfringens and Escherichia coli, both capable of producing supertoxins as well.
Mimicking a baby鈥檚 movement also created clouds of bugs in the air above a mattress. 鈥淔our hours after throwing up, there could be 10,000 bacteria in the air, enough to cause infection,鈥� says Sherburn.
Ironically, non-integral 鈥渂reathable鈥� mattresses were introduced in the 1990s to overcome perceived dangers of mattresses fully covered with PVC. The theory, now largely rejected, was that fungi inside the PVC covering broke down flame retardants in the plastic and released toxic vapours that poisoned babies. But Sherburn鈥檚 work is adding weight to other studies suggesting breathable mattresses actually pose the highest risks.
鈥淭his research supports our advice to keep cot mattresses well-aired and clean,鈥� says a spokeswoman for Britain鈥檚 Foundation for the Study of Infant Death. 鈥淎 mattress with a PVC cover or a removable, washable cover is easiest to keep clean.鈥� However, she adds that there could well be several different causes of cot death.