Aciduric microbiota and mutans streptococci in severe and recurrent severe early childhood caries.

PURPOSE: Severe early childhood caries (ECC) results from bacterial acid production in an acidic environment. The purpose of this study was to determine Streptococcus mutans, Streptococcus sobrinus, and acid-tolerant counts in severe early childhood caries. METHODS: Two- to 6-year-olds with severe-ECC (N=77) or who were caries-free (N=40) were examined. Plaque samples from teeth and the tongue were cultured anaerobically on blood, acid, and S. mutans selective agars. Severe-ECC children were monitored post-treatment for recurrent caries. RESULTS: Severe-ECC and caries-free children were balanced by household income and education level. Carious lesions were observed in 75% maxillary incisors and >80% molars in severe-ECC. At baseline, S. mutans, and S. sobrinus counts and proportions of S mutans were higher in severe-ECC than caries-free children. Acid and blood counts were elevated only in anterior samples of severe-ECC children. Baseline counts of S. sobrinus, but not S. mutans, were higher in children with recurrent compared with no recurrent caries. S. mutans counts were lower following treatment than pretreatment, particularly for children without caries recurrence. Other counts did not differ between before and after therapy. CONCLUSIONS: Severe and recurrent early childhood caries was better explained by mutans streptococci than the aciduric microbiota. Streptococcus mutans did not predict children with recurrent caries.

A critical review of the U.S. EPA's risk assessment for the land application of sewage sludge.

Sewage sludge is a complex mixture of inorganic and organic materials and pathogens generated by the treatment of domestic sewage. Section 40 of the Code of Federal Regulations Part 503 regulates the land application of sewage sludge based on pathogen content and sets standards for nine inorganic chemicals. It is believed that the Part 503 standards are protective of human health and the environment and that sewage sludge applied to land poses little risk. A critical inspection of the pertinent literature, however, reveals that the standards were based on outdated methods, outdated data, inaccurate data, and flawed assumptions, leading to underestimation of risk. The standards are not sufficiently protective, and even if changes were made, sewage sludge is so complex that it is very unlikely it could be monitored to ensure the protection of human health and the environment. For these reasons, the practice of land application of sewage sludge must be discontinued.