Screening the enteroaggregative Escherichia coli activity and detection of the aggA, aafA, and astA genes with novel PCR primers for the Escherichia coli isolates from diarrhea cases in Taiwan

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• 作者：Tsai ; Cheng-Chih ; Chen ; Shu-Yu ; Tsen ; Hau-Yang
• 关键词：Enteroaggregative Escherichia coli ; Adhesion ; Hemagglutination ; Bacterial clumping test ; PCR
• 刊名：Diagnostic Microbiology and Infectious Disease
• 出版年：2003
• 出版时间：July, 2003
• 年：2003
• 卷：46
• 期：3
• 页码：159-165
• 全文大小：165 K

文摘

Enteroaggregative Escherichia coli (EAggEC) are emerging enteropathogens associated with human diarrhea diseases and food poisoning cases. They show distinctive aggregative pattern of adherence to cultured human epithelial cells. However, EAggEC strains are diverse and not all of them have the aggregative adherence fimbria I (AAF/I), AAF/II and heat-stable enterotoxin 1 (EAST1) genes. We attemptd to determine the incidence of EAggEC in E. coli isolates from diarrhea patients in Taiwan and to characterize these EAggEC strains. We used three activity assays including HeLa cell adhesion, human blood hemagglutination and bacterial clumping tests and polymerase chain reaction (PCR) primers designed from an aggregative adherence pattern associated plasmid (pCVD432) to screen the EAggEC strains in 403 E. coli isolates including 63 laboratory isolates and 340 clinical isolates obtained from diarrheal disease cases. All these 403 E. coli strains were also assayed with novel PCR primers designed from AAF/I (aggA), AAF/II (aafA) and EAST1 (astA) genes. Results showed that except for the three EAggEC reference strains, only three clinical isolates were identified as EAggEC strains. Including the reference strains, all the E. coli strains with EAggEC activity generated positive PCR results to the aggA gene based primers, but not to the aafA and astA gene targeted primers.