Relationship between the presence of newborn and the house dust endotoxin.

ABSTRACT

BACKGROUND: Exposure to house dust endotoxin induces of airways' inflammation. Endotoxin are produced by the Gram-negative bacteria, which are released into the stools and could contaminate domestic environment. OBJECTIVE: The newborn could contaminate his mattress by endotoxin. METHODS: The dusts of mattress and carpets of 97 newborn' dwellings were sampled at birth and after six months of life. Samplings were made in the bedroom from the baby and in the second place where the baby spent the longer time. The endotoxin concentration was measured by a quantitative Limulus assay and the bacterial contamination was evaluated using 3 selective agar media. RESULTS: Endotoxin concentration at birth was positively associated with the presence of both sibling and the number of inhabitants (p<0.01). At 6 months of life, the endotoxin concentration raised significantly not only in the mattresses (from a median of 17.6 (ranges 0.4-346.7) to 79.6 (3.8-518.8) EU/mg) (p<0.0001), but also in the dust from the second place where the baby is sleeping (from 20.4 (0.8-226.3) to 101.8 (6.5-634.3) EU/mg) (p<0.001). Importantly, there was no change in endotoxin concentration from the carpets dust, and the environmental dwelling characteristics remained unchanged. The total bacterial contamination was also positively associated with endotoxin concentration in newborn mattress at birth (p<0.01) and showed a significant increase at 6 months of life of the newborn (p<0.01). CONCLUSION: The newborn is a significant source of house dust's endotoxin.