An outbreak of gastroenteritis in Osaka, Japan due to Escherichia coli serogroup O166[ratio ]H15 that had a coding gene for enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1)

Abstract

In an outbreak of gastroenteritis on 23 July 1996, in Osaka, Japan, 54 of 91 persons who had attended a meeting the previous day became ill. Escherichia coli O166:H15 was isolated from stool specimens of patients (29/33, 88%). Laboratory tests for other bacterial pathogens and viruses were negative. The E. coli 0166 organisms did not adhere to HEp-2 cells in a localized, diffuse, or enteroaggregative manner. The organisms did not express known enterotoxigenic E. coli (ETEC) colonization factors. In polymerase chain reaction tests, the bacteria did not have coding genes for shigatoxin of enterohemorrhagic E. coli (EHEC), heat-labile, or heat-stable enterotoxin of ETEC, attachment and effacement (eaeA) of EPEC, or invasion (invE) of enteroinvasive E. coli (EIEC). Consequently, they could not be assigned to any of the recognized diarrhoeagenic groups of E. coli: EPEC, ETEC, EHEC, EIEC, enteroaggregative E. coli (EAggEC), or diffusely adhering E. coli. However, the organisms possessed the EAggEC heat-stable enterotoxin (EAST1) gene. To our knowledge, this is the first report of an outbreak caused by E. coli that did not have well-characterized virulence genes other than EAST1. The isolates showed the same DNA banding pattern in pulsed-field gel electrophoresis after digestion with the restriction enzymes XbaI or NotI. Three O166:H15 strains isolated from two sporadic cases and another outbreak during 1997-8 were distinct, indicating that multiple clones have spread already. We propose that diarrhoeal specimens should be examined for E. coli possessing the EAST1 gene.

An Outbreak of Foodborne Illness Caused by Enteroaggregative <i>Escherichia coli</i> in a High School in South Korea

“…In the past, the astA gene was considered characteristic of EAEC strains (7), despite its detection, in only a subgroup of EAEC strains, and its extensive distribution among other E. coli strains (28,29). In our study, none of the EAEC isolates harbored the astA gene.…”

Prevalence of Diarrheagenic <i>Escherichia coli</i> in Foods and Fecal Specimens Obtained from Cattle, Pigs, Chickens, Asymptomatic Carriers, and Patients in Osaka and Hyogo, Japan

“…Domestic animals are thought to be natural carriers of EAST1EC and EPEC. In 1996, EAST1EC O166:H15 was detected as the sole etiological agent causing outbreaks in Japan among adult patients (28). In addition, EAST1EC was often detected in children suffering from diarrhea (32).…”

ウシ由来大腸菌が保有する病原性に関与する遺伝子群の包括的実態調査

“…Among 12 pathogenic genes investigated, astA showed the highest detection rate (37 ) and was distributed widely among DEC including STEC, ETEC, and EPEC. In addition to the broad distribution of astA 11) , an outbreak of gastroenteritis caused by E. coli that did not have well-characterized pathogenic genes other than astA was also reported 12) . In this study, 40 DEC carrying astA only were isolated from cattle.…”