ADHERENCE PATTERNS AND ADHERENCE-RELATED DNA-SEQUENCES IN ESCHERICHIA-COLI ISOLATES FROM CHILDREN WITH AND WITHOUT DIARRHEA IN SAO-PAULO CITY, BRAZIL

The correlation between various adherence patterns and adherence-relat ed DNA sequences in Escherichia coli isolates from 1- to 4-year-old ch ildren with and without diarrhea in Sao Paulo, Brazil, was evaluated. A total of 1,801 isolates obtained from 200 patients and 200 age-match ed controls were studied. The adherence patterns found were classified as diffuse, aggregative, aggregative in a 6-h assay, aggregative pred ominantly in coverslips, localized, localized-like, and noncharacteris tic. In general, the DNA sequences used as probes showed excellent spe cificities (>93%), but their sensitivities varied. Thus, the results o f bioassays and assays with DNA probes normally used to search for adh erent E. coli did not correlate well, and the best method for the iden tification of these organisms in the clinical research setting remains controversial. Isolates presenting diffuse adherence or hybridizing w ith the related daaC probe, or both, were by far the most frequent in patients (31.5, 26.0, and 23.0%, respectively), followed by isolates p resenting aggregative adherence or hybridizing with the related EAEC p robe, or both (21.5, 13.0, and 10.5%, respectively). None of the diffe rent combinations of adherence patterns and adherence-related DNA sequ ences found were associated with acute diarrhea.