Konno Takayuki, Yatsuyanagi Jun, Saito Shioko
Health and Hygiene Division, Akita Prefectural Research Center for Public Health and Environment, Akita, Japan.
FEMS Immunol Med Microbiol. 2012 Apr;64(3):314-20. doi: 10.1111/j.1574-695X.2011.00913.x. Epub 2011 Dec 14.
Between 2007 and 2009, a total of 2168 Escherichia coli strains derived from diarrheal patients, defined as putative diarrheagenic E. coli (DEC), were collected from medical institutions in Akita prefecture, Japan. Thirty five of the strains lacked typical pathogenic determinants of DEC other than astA, which encodes enteroaggregative E. coli (EAggEC) heat-stable enterotoxin 1 (EAST1). These E. coli strains are referred to as EAST1EC. Several studies have suggested a role of EAST1 in diarrhea; however, the correlation between diarrhea and the presence of astA remains inconclusive. To investigate whether EAST1EC strains derived from diarrheal patients shared pathogenic factors other than EAST1, virulence gene profiling of 12 virulence genes - iha, lpfA, ldaG, pilS, pic, pet, irp2, daa, aah, aid, cdtB and hlyA - was carried out. PCR analysis revealed that four of the 35 EAST1EC strains harbored only astA, 24 harbored genes associated with adhesins and intestinal colonization, three strains harbored the gene for α-hemolysin, and 24 strains harbored the gene for a siderophore. These results indicated that some EAST1EC strains harbor various virulence genes associated with distinct E. coli pathotypes, primarily enterohemorrhagic E. coli and EAggEC, which may represent additional pathogenic determinants of EAST1EC.
2007年至2009年间，从日本秋田县的医疗机构收集了总共2168株源自腹泻患者的大肠杆菌菌株，这些菌株被定义为疑似致泻性大肠杆菌（DEC）。其中35株菌株除了编码肠集聚性大肠杆菌（EAggEC）热稳定肠毒素1（EAST1）的astA外，缺乏DEC的典型致病决定因素。这些大肠杆菌菌株被称为EAST1EC。多项研究表明EAST1在腹泻中起作用；然而，腹泻与astA存在之间的相关性仍无定论。为了研究源自腹泻患者的EAST1EC菌株是否共享除EAST1之外的致病因素，对12个毒力基因——iha、lpfA、ldaG、pilS、pic、pet、irp2、daa、aah、aid、cdtB和hlyA进行了毒力基因谱分析。PCR分析显示，35株EAST1EC菌株中有4株仅携带astA，24株携带与黏附素和肠道定植相关的基因，3株携带α-溶血素基因，24株携带铁载体基因。这些结果表明，一些EAST1EC菌株携带与不同大肠杆菌致病型相关的各种毒力基因，主要是肠出血性大肠杆菌和EAggEC，这可能代表了EAST1EC的其他致病决定因素。
