DEVELOPMENT OF PCR FOR SCREENING OF ENTEROAGGREGATIVE ESCHERICHIA-COLI

In this study, we determined the sequence of the EcoRI-PstI fragment o f the plasmid pCVD432, also termed the enteroaggregative Escherichia c oli (EAggEC) probe. A primer pair complementary to this probe,vas desi gned for PCR amplification of a 630-bp region. Comparison of the analy sis of the EAggEC probe sequence with those in database libraries reve aled no significant similarity to any known bacterial gene. Pure cultu res of E. coli cells, as well as mixed cultures from stool specimens, were investigated with the PCR assay, the EAggEC probe test, and the a dherence test, Of 50 E. coli strains which demonstrated aggregative ad herence to HEp-2 cells, 43 (86%) were positive with the EAggEC PCR. Al l 43 of these strains reacted with the EAggEC probe. Six EAggEC strain s gave negative results by both molecular techniques. In contrast, onl y 4 of 418 (0.96%) strains representing other categories of diarrheage nic E. coli demonstrated a positive PCR result. The PCR was also succe ssful in screening for the presence of EAggEC in enriched cultures gro wn from steal specimens. Compared with cell culture assays and colony hybridization, our findings revealed that the PCR assay was more rapid , simple, and highly sensitive and can therefore be recommended as a s creening method for EAggEC in the clinical laboratory.