Prevalence of theeaeA gene in verotoxigenicEscherichia colistrains from dairy cattle in Southwest Ontario

Abstract

This study determined the prevalence of the eaeA gene and its relationship to serotype and type of verotoxin produced in a collection of 432 verotoxigenic Escherichia coli (VTEC) obtained from the faeces of healthy cows and calves in a systematic random survey involving 80 dairy farms in Southwest Ontario. A PCR amplification procedure involving primer pairs which target the conserved central region of the O157:H7 eaeA gene showed that 151 (35.2%) strains were positive for the eaeA gene. All isolates (9-21 for each O group) of O groups 5, 26, 69, 84, 103, 111, 145 and 157 were positive, whereas all isolates (7-34 for each O group) of O groups 113, 132, and 153 and serotype O156:NM (38 isolates) were negative for eaeA. Seventy-three percent of 130 isolates of eaeA-positive serotypes produced VT1 only compared with 20% of 253 isolates of eaeA-negative serotypes. We conclude that there is a strong association between certain O groups and the eaeA gene, that serotypes of eaeA-positive and eaeA-negative VTEC implicated in human and cattle disease are present at high frequency in the faeces of healthy cattle, that VT1 is more frequently associated with eaeA-positive than with eaeA-negative serogroups, and that the eaeA gene is more frequently found in VTEC from calves compared with VTEC from adult cattle.

Prevalence and molecular detection of shiga toxin producing Escherichia coli from diarrheic cattle

“…This result was also reported by Nazir et al (2005) and Rehman et al (2014). Fecal isolates revealed a complete fermentation of basic sugars as stated by Beutin et al (1993), Sandhu et al (1996) and Mckec et al (1995). E. coli isolates were able to ferment the five basic sugars producing both acid and gas; however, differentiation of E. coli into species level was difficult as showed similar reaction in various sugars (Elafify et al, 2016).…”

The prevalence and characterization of verotoxin-producing Escherichia coli isolated from cattle and pigs in an abattoir in Hong Kong

“…Onethird of these strains belonged to serotype O172, which has been isolated from one patient with HC in America [32] but was infrequently encountered in both humans and animals elsewhere [33,34]. The first reported O172 strains harboured t2 as did the O172 isolates described here.…”

Role of non-O157 VTEC

“…Strains of VTEC 0111 :H-have been isolated from calves and adult cattle in the USA (Dorn et al 1993) and Italy (Farina et al 1996), respectively. The same serotype has also been isolated from healthy cattle in Canada Sandhu et al 1996;Wilson et al 1996), in the USA (Wells et al 1991) and in Belgium and Germany (Wieler et al 1996). In the latter study, VTEC 0111 :H2 was also isolated from healthy cattle.…”

“…To date VTEC 0111:H8 and 0111:Hll have only been isolated from cattle in North America. VTEC 0111 :H8 was isolated in Canada from healthy cattle (Sandhu et al 1996;Wilson et al 1996) and from cattle with HC ). In the latter study, VTEC Olll:Hll was also isolated.…”

“…1993;Clarke et al 1994;Sandhu et al 1996), while VTEC 0l03:H2 has been isolated only from healthy cattle, predominantly in North America Dorn et al 1989;Wells et al 1991;Wilson et al 1994Wilson et al , 1996Sandhu et at. 1996) and in Europe.…”