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

Abstract

Pathogenic genes such as stx1, stx2, STh gene, STp gene, LT gene, invE, eae, aggR, afaD, astA, cdt and cnf were investigated in Escherichia coli isolated from cattle during Nov. 2012 and Aug. 2013. Plural pathogenic genes were concurrently detected by multiplex PCR, and screen-positive genes were confirmed and sub-classified by PCR. Among 100 cattle investigated, 180 E. coli strains with diarrheic genes (DEC) were detected in 79 cattle, and 45 of them, isolated from 32 cattle, were Shiga toxin-producing E. coli (STEC). More than 30 of cattle carried astA, cdt, cnf and stx2 in descending order. STh gene, LT gene, invE, aggR and afaD were not detected in this study. Both stx1 and stx2 were concurrently detected from 6 of 45 STEC strains and stx2 alone was detected from 19. Seventeen STEC strains carried STp gene, astA, or cdt along with stx1 or stx2. Additionally, 135 remaining DEC were classified into 18 enterotoxigenic E. coli with STp gene, 25 enteropathogenic E. coli with eae, and 92 other DEC with astA, cdt and cnf. Both O and H serotypes were identified in 48 strains, including O157 : H7, O1H7 and so on. O157 : H7 were identified in 3 strains that carried stx2 and eae together, as found in human pathogenic strains isolated from patients with gastroenteritis and hemolytic-uremic syndrome.

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

“…Although EAEC is relatively rare among humans, this pathotype is still significantly more prevalent in human fecal samples compared to those of animals. Our results are consistent with the findings of Akiyama et al (31), who reported that aggR was not detected in any of the cattle-derived DEC examined. The reservoir for EAEC is likely humans.…”

“…In the present study, foods and fecal specimens were screened using a multiplex realtime PCR protocol. Our experiments revealed that enterovirulence genes, especially astA and eae, were more common in cattle, pigs, and chickens than has been previously reported in studies using culture methods (31). Domestic animals are thought to be natural carriers of EAST1EC and EPEC.…”

“…Cattle are considered to be a major source of diarrheagenic aEPEC, as described in our molecular epidemiological studies (24,31). Specifically, patient strains were closer to bovine strains, while aEPEC from healthy carriers could be discriminated from the other aEPEC, including patient strains.…”

Shiga Toxin Subtypes and Virulence Genes in <i>Escherichia coli</i> Isolated from Cattle

“…Bacterial strains and template DNA preparation: E. coli strains carrying virulence genes were isolated from the intestinal ingredients of cattle, as previously described (13). Forty-five STEC strains isolated from 32 Japanese Black cattle (20 oxen and 12 cows) bred in Hyogo Prefecture were used in this study.…”

Public health risks associated with Enteroaggregative Escherichia coli (EAEC) as a food‐borne pathogen

“…None of the faecal samples contained the four markers simultaneously, indicating that cattle in France were not likely to be a reservoir of O104:H4, but results of the test for aggR were not reported (Auvray et al, 2012). In a recent study of 100 clinical cases in cattle in Japan, no EAEC isolates, as assessed by the presence of aggR, were detected (Akiyama et al, 2015).…”