Prevalence and Characteristics of eae -Positive Escherichia coli from Healthy Cattle in Japan

Abstract

The prevalence of eae-positive Escherichia coli (eaeEC) in Japan was examined using rectal stool samples taken from 35 calves less than 1 month old, 107 calves more than 1 to 3 months old, 88 heifers more than 3 to 6 months old, 214 heifers over 6 months old, and cows from 95 farms. Screening with eae PCR revealed the prevalence to be, with increasing age, 31.4, 8.4, 26.1, and 14.5%, respectively. Of 51 selected eaeEC strains, more than 40% were serotyped as O26, O103, O111, O145, or O157, which are frequently detected as enterohemorrhagic E. coli types. Four strains were identified as recently reported intimin types , , and .Enterohemorrhagic Escherichia coli (EHEC), enteropathogenic E. coli (EPEC), and attaching and effacing E. coli (AEEC) are food-borne pathogens that can cause diarrhea in humans (7,11,15). These pathogenic E. coli types often possess genes coding for Shiga toxins (stx genes) and for intimin (eae), an outer membrane protein. E. coli strains with stx genes are called Shiga toxin-producing E. coli (STEC). Cattle are considered to be the main reservoir of STEC strains, including EHEC strains (2, 3). STEC strains are classified into more than 200 O serotypes (4, 16); however, the majority of outbreaks and/or sporadic cases of hemorrhagic colitis and hemolyticuremic syndrome in humans have been caused by the members of only a few serogroups, such as O26, O111, and O157 (10,17,19). Since the strains of these limited O serogroups almost all possess eae (3, 9), this gene may be a more useful target than the stx genes for screening EHEC strains in cattle fecal samples.We used PCR to investigate the prevalence of eae-positive E. coli in cattle feces and genetically characterized the intimin types found, as well as various virulence genes seen in the isolated strains.E. coli O157:H7 strain ATCC 35150 (American Type Culture Collection, Manassas, Va.) was used as the positive control for stx 1 , stx 2 , eae, and intimin type ␥ (intimin ␥). The E. coli strains JS144, 166, VR299-2, and EPEC108, which were used as positive-control strains for intimins ␣, ␤, and ε and bundleforming pilus (bfp), respectively, were derived from the stock culture collection of the National Institute of Animal Health, Tsukuba, Japan. A total of 444 rectal stool grab samples were collected from healthy dairy cattle (35 calves under 1 month old, 107 calves more than 1 to 3 months old, 88 heifers more than 3 to 6 months old, 214 heifers more than 6 months old, and cows) on 95 farms located in the western and central parts of Japan between May and November 2001. All rectal stool samples were sampled by veterinarians at regional governmental animal hygiene centers. The samples were placed in cool boxes (4 to 8°C) and taken to the laboratory for immediate processing (usually within 24 h). Each sample of 1 g of rectal stool was enriched in 19 ml of Trypticase soy broth (Eiken, Tokyo, Japan) at 37°C for 18 h. Ten microliters of the Trypticase soy broth culture was inoculated onto MacConkey agar (MAC; Eiken). The MAC plates were incubated...

Characterization of Shiga Toxin-Producing Escherichia coli Strains Isolated from Human Patients in Germany over a 3-Year Period

“…In this study, we have detected intimin in eight STEC strains with flagellar type H25 (O109:H25, O156:H25, Ont:H25, and Orough:H25) which were positive for EHEC hlyA and, except in Ont:H25 (toxin type 2) strains, for toxin type 1 ( Table 1). Intimin was recently described to occur in bovine STEC strains which belonged to serotypes other than those of our human STEC isolates (33,38). Intimin ␣ was previously detected in EPEC but not in STEC strains (7,32,55) and was detected in our study in two strains representing a new STEC serotype, O177:…”

Shiga Toxin Gene-Containing Escherichia coli from Cattle and Diarrheic Children in the Pastoral Systems of Southwestern Uganda

“…Although the proportion of intimin-positive strains from cattle varies with the time of sampling (10), the overall high frequency of eae-positive isolates (14 of 20 bovines) was unexpected, as previous studies have shown a much lower prevalence of eae-positive STEC isolates in healthy cattle (2,4,10,12).…”

“…Surprisingly, the two bovine STEC O113 strains were eae positive, and one of these strains was closely related to the isolate from child H4. Strains belonging to this serogroup are prevalent in cattle (3,12), and O113 strains have been implicated in sporadic cases of hemolyticuremic syndrome (3,7,11,13,15); however, these STEC O113 strains have typically been eae negative (3,7,12,13,15). O158 To the best of our knowledge, this is the first study on the occurrence of STEC in bovines in a seminomadic pastoralist community in Uganda.…”

Sequence Analysis of the Escherichia coli O15 Antigen Gene Cluster and Development of a PCR Assay for Rapid Detection of Intestinal and Extraintestinal Pathogenic E. coli O15 Strains

“…Subtyping of the LEE encoded eae (intimin) genes in the rabbit EPEC O15:NM protype strain RDEC-1 and in a bovine EPEC O15:NM revealed the intimin beta type (23,39). Intimin-positive E. coli O15 strains were also occasionally isolated from human patients with diarrhea (10,60), but the relationship between O15 EPEC from humans and animals is not well known.…”