Identification of Different Categories of Diarrheagenic Escherichia coli in Stool Samples by Using Multiplex PCR Technique

Diarrheal diseases continue to be one of the most common causes of morbidity and mortality among young children in developing countries. The objective of this s tudy was to evaluate the multiplex PCR as a rapid diagnostic tool for simultaneous detection of four categories of diarrheagenic E. coli (ETEC, EPEC, EHEC and EAEC) in one PCR reaction using six virulent genes. During the period from June 2009 to September 2009, 50 stool samples were collected from children suffering from diarrhea in Pediatric Teaching Hospital at Sulaimani and Karkuk cities. E coli were isolated and diagnosed using set of conventional biochemical tests and API 20E system. Two different methods of DNA extraction (salting out and boiling) were used, and then the DNA was used as a template for PCR. The multiplex PCR detected target genes of diarrheagenic E. coli in 19 out of the 50 diarrheal stools specimens (38%). Genes of ETEC (lt or st) were detected in 5/19 specimens (26.3%). Gene of EPEC (eae and/or bfp) was detected in 12/19 specimens (63.1% ). Genes of EAEC was detected in 4/19 specimens (21%), two of them (10.5%) were showed EAEC plus EPEC and EAEC plus ETEC denoting mixed infection. Genes for EHEC were not detected in any of the diarrheal specimens. Multiplex PCR for the simultaneous detection of several pathogenic genes in one PCR reaction will save time and effort involved in analyzing various virulence factors and will help investigators to clarify the role of Diarrhoeagenic E. coli in diarrheal diseases.