Open AccessBiofilm formation by South African non-O157 Shiga toxigenic Escherichia coli on stainless steel coupons
Author(s) -
Emmanuel W. Bumunang,
Collins Njie Ateba,
Kim Stanford,
Tim A. McAllister,
Yan Niu
Publication year - 2020
Publication title -
canadian journal of microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.635
H-Index - 94
eISSN - 1480-3275
pISSN - 0008-4166
DOI - 10.1139/cjm-2019-0554
Subject(s) - biofilm , microbiology and biotechnology , incubation , crystal violet , escherichia coli , staining , food science , biology , chemistry , bacteria , gene , biochemistry , genetics
This study examined the biofilm-forming ability of six non-O157 Shiga-toxin-producing Escherichia coli (STEC) strains: O116:H21, wzx-Onovel5:H19, O129:H21, O129:H23, O26:H11, and O154:H10 on stainless steel coupons after 24, 48, and 72 h of incubation at 22 °C and after 168 h at 10 °C. The results of crystal violet staining revealed that strains O129:H23 and O154:H10 were able to form biofilms on both the submerged surface and the air–liquid interface of coupons, whereas strains O116:H21, wzx-Onovel5:H19, O129:H21, and O26:H11 formed biofilm only at the air–liquid interface. Viable cell counts and scanning electron microscopy showed that biofilm formation increased (p < 0.05) over time. The biofilm-forming ability of non-O157 STEC was strongest (p < 0.05) at 22 °C after 48 h of incubation. The strongest biofilm former regardless of temperature was O129:H23. Generally, at 10 °C, weak to no biofilm was observed for isolates O154:H10, O116:H21, wzx-Onovel5:H19, O26:H11, and O129:H21 after 168 h. This study found that temperature affected the biofilm-forming ability of non-O157 STEC strains. Overall, our data indicate a high potential for biofilm formation by the isolates at 22 °C, suggesting that non-O157 STEC strains could colonize stainless steel within food-processing facilities. This could serve as a potential source of adulteration and promote the dissemination of these potential pathogens in food.