An Evaluation of Cot Mattresses and their Covers as Reservoirs of Toxigenic Bacteria

Dr Richard Jenkins, Professor Peter Craig and Dr Tania Webb
De Montfort University, Leicester
(2000: £58,425 over 2 years)

The purpose of this research was to investigate the possibility that potentially harmful bacteria might become established in cot mattress foams and/or their covers, giving rise to sources of possible infection that may invade the upper respiratory tract of infants.

The methodology involved bacteriological testing of currently used polyurethane foam cot mattresses donated by the public. Information on the history of use of the cot mattresses was obtained via a mattress donor questionnaire.

The study found that the bacteria in cot mattresses was influenced by the sleeping position of the infant. Movement on a cot mattress promoted aerial release of bacteria from polyurethane foam. Use of a non-integral (not completely covered in plastic) cot mattress was associated with increased levels of bacterial contamination within the exposed polyurethane foam. Previous use by another child of a non-integral mattress was associated with significantly increased levels of Staphylococcus aureus within cot mattress polyurethane foams. This is a bacterium which is found more frequently in infants who have died suddenly and unexpectedly than in infants who have died from known causes.

The findings could provide a plausible explanation for recently identified possible risk factors for SIDS, i.e. sleeping at night on mattresses used previously by another child and use of mattresses not entirely covered with a waterproof cover. Data obtained on soluble protein and dust-mite allergen levels within polyurethane foams corroborate these findings. The fact that bacterial growth/survival is encouraged by organic matter contamination, such as urine, breast or formula milk, or by high relative humidity, indicates that maintenance of a clean and dry cot environment would help to minimise development of reservoirs of bacteria within cot mattress materials. Staphylococcus aureus was shown to have good survival capability on polyurethane foam even at low relative humidity and to be capable of breakdown of polyurethane.

This study shows that it is important to keep your cot dry and clean, to use a mattress that is completely covered with plastic, and to use a new mattress for each baby if you can. More information on using the right bedding, see here.