|Attachment and biofilm formation by Escherichia coli O157H7 on stainless steel|
|Year of publication||2004년 이전|
|Author||Ryu, J.H., Kim. H. K., & L. R. Beuchat.|
|Publication in journal||Journal of Food Protection, Vol. 67, No. 10, 2004, Pages 2123–2131|
|Status of publication||Publised|
The inﬂuence of exopolysaccharide (EPS) production, nutrient availability, and temperature on attachment and bioﬁlm formation by Escherichia coli O157:H7 strains ATCC 43895 (wild type) and 43895-EPS (extensive EPS-producing mutant) on stainless steel coupons (SSCs) was investigated. Cells grown on heated lettuce juice agar and modiﬁed tryptic soy agar were suspended in phosphate-buffered saline (PBS). SSCs were immersed in the cell suspension (109 CFU/ml) at 4°C for 24 h. Bioﬁlm formation by cells attached to SSCs as affected by immersing in 10% tryptic soy broth (TSB), lettuce juice broth (LJB), and minimal salts broth (MSB) at 12 and 22°C was studied. A signiﬁcantly lower number of strain 43895-EPS cells, compared to strain ATCC 43895 cells, attached to SSCs during a 24-h incubation (4C) period in PBS suspension. Neither strain formed a bioﬁlm on SSCs subsequently immersed in 10% TSB or LJB, but both strains formed bioﬁlms in MSB. Populations of attached cells and planktonic cells of strain ATCC 43895 gradually decreased during incubation for 6 days in LJB at 22°C, but populations of strain 43895-EPS remained constant for 6 days at 22°C, indicating that the EPS-producing mutant, compared to the wild-type strain, has a higher tolerance to the low-nutrient environment presented by LJB. It is concluded that EPS production by E. coli O157:H7 inhibits attachment to SSCs and that reduced nutrient availability enhances bioﬁlm formation. Bioﬁlms formed under conditions favorable for EPS production may protect E. coli O157:H7 against sanitizers used to decontaminate lettuce and produce processing environments. Studies are under way to test this hypothesis.