Shigella and enteroinvasive Escherichia coli infections in households of children with dysentery in Bangkok.

Shigellae and enteroinvasive Escherichia coli (EIEC) were identified in children with dysentery and their household contacts in Bangkok. Shigellae were isolated from 49% and EIEC from 6% of 306 children with dysentery seen at the outpatient department of Children's Hospital on weekdays during January through June 1989 and October 1989 through October 1990. The same serotype infecting the index child was isolated from 21 (4%) of 522 household contacts of 151 index children with Shigella infections and from none of 60 household contacts of 19 index children with EIEC infections. Amplification of DNA sequences coding for the invasion-associated locus (ial) by polymerase chain reaction increased the identification of Shigella and EIEC infections from 57% (111/193) to 68% (132/193). ial sequences were identified in 3 of 20 drinking water specimens from which shigellae or EIEC were not isolated. Amplification of ial sequences identified more shigellae and EIEC than did bacteriologic and colony hybridization methods in children with dysentery and in drinking water in Bangkok.