A SIMPLE POLYMERASE CHAIN-REACTION TECHNIQUE TO DETECT AND DIFFERENTIATE SHIGELLA AND ENTEROINVASIVE ESCHERICHIA-COLI IN HUMAN FECES

A simple polymerase chain reaction (PCR) procedure using IS630-specifi c primers was developed as a general diagnostic probe to detect Shigel la and enteroinvasive Escherichia coli (EIEC). However, IS630 and the other two previously reported molecular probes, ipaH and iaI, cannot b e used to differentiate among Shigella serotypes and EIEC strains that cause dysentery. The sensitivity of PCR protocol was determined to be 100-200 shigellae for each PCR reaction. An enrichment incubation wou ld allow the detection of shigellae in stool samples with low bacteria l concentration; i.e., <10(4) CFU/gram. Serotype-specific primers deri ved from the rfc genes of different Shigella strains were used in PCR reactions to differentiate among Shigella serotypes in the laboratory, such as S. sonnei, S. flexneri, and S. dysenteriae 1. It was demonstr ated further that the multiplex PCR system containing rfc-specific pri mers can efficiently identify the most prominent Shigella serotypes in raw stool samples of acute diarrheal patients. (C) 1997 Elsevier Scie nce Inc.