title: Biofilm Formation, Virulence Gene Profiles, and Antimicrobial Resistance of Nine Serogroups of Non-O157 Shiga Toxin-Producing Escherichia coli.
abstract: The objectives of this study were to characterize the phenotype and genotype of 36 non-O157 Shiga toxin-producing Escherichia coli (STEC) strains isolated from humans, ovines, or bovines, including the top 6 (O26, O45, O103, O111, O121, and O145) and three other serogroups implicated in serious illness (O91, O113, and O128). Biofilms were formed by all strains with intermediate to strong biofilm producers (n = 24) more common at 22°C than at 37°C (p < 0.001) and 48 and 72 h (p < 0.001) than 24 h of incubation time. Biofilm-forming potential differed by serogroup and origin with O113 and human strains exhibiting the highest potential (p < 0.001). Biofilm-associated genes, csgA/csgD/crl/fimH (100%), flu (94%), rpoS (92%), ehaA(α) (89%), and cah (72%), were most prevalent, while mlrA (22%) and ehaA(β) (14%) were least prevalent, although there was no clear compliment of genes associated with strains exhibiting the greatest biofilm-forming capacity. Among 12 virulence genes screened, iha and ehxA were present in 92% of the strains. The occurrence of stx1 in the top 6 serogroups (8/12, 67%) did not differ (p = 0.8) from other serogroups (17/24, 71%), but stx2 was less likely (confidence interval [CI] = 0.14-1.12; p = 0.04) to be in the former (9/24, 38%) than the latter (9/12, 75%). Excluding serogroups, O91 and O121, at least one strain per serogroup was resistant to between three and six antimicrobials. Streptomycin (31%), sulfisoxazole (31%), and tetracycline (25%) resistance was most common and was 35-50% less likely (p < 0.05) in human than animal strains. All non-O157 STEC strains were able to form biofilms on an abiotic surface, with some exhibiting resistance to multiple antimicrobials. Potential as a reservoir of antimicrobial resistance genes may be another hazard of biofilms in food-processing plants. As a result, future strategies to control these pathogens may include measures to prevent biofilms.
authors.affiliation: 1 National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University , Dalian, China .|2 College of Veterinary Medicine, South China Agricultural University , Guangzhou, China .|3 Agriculture and Agri-Food Canada , Lethbridge, Alberta, Canada .
authors.forename: Jiaying
authors.initials: J
authors.lastname: Wang
authors.affiliation: 4 Alberta Agriculture and Forestry , Lethbridge, Alberta, Canada .
authors.forename: Kim
authors.initials: K
authors.lastname: Stanford
authors.affiliation: 3 Agriculture and Agri-Food Canada , Lethbridge, Alberta, Canada .
authors.forename: Tim A
authors.initials: TA
authors.lastname: McAllister
authors.affiliation: 5 National Microbiology Laboratory, Public Health Agency of Canada , Guelph, Ontario, Canada .
authors.forename: Roger P
authors.initials: RP
authors.lastname: Johnson
authors.affiliation: 2 College of Veterinary Medicine, South China Agricultural University , Guangzhou, China .
authors.forename: Jinding
authors.initials: J
authors.lastname: Chen
authors.affiliation: 1 National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University , Dalian, China .
authors.forename: Hongman
authors.initials: H
authors.lastname: Hou
authors.affiliation: 1 National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University , Dalian, China .
authors.forename: Gongliang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: 4 Alberta Agriculture and Forestry , Lethbridge, Alberta, Canada .
authors.forename: Yan D
authors.initials: YD
authors.lastname: Niu
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000254:growth & development; D002170:Canada; D002417:Cattle; D024881:Drug Resistance, Bacterial; D005516:Food Microbiology; D006801:Humans; D010641:Phenotype; D065288:Serogroup; D012756:Sheep; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors