Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/10/2012
Publication Date: 6/16/2012
Citation: Wang, R., Bono, J.L., Kalchayanand, N., Shackelford, S.D., Harhay, D.M. 2012. Biofilm formation by foodborne pathogens and their resistance to sanitization. [Abstract]. Americian Society for Microbiology, 112th General Meeting. Poster No 2154, session 170.
Technical Abstract: Shiga-toxin producing Escherichia coli (STEC) and multi-drug resistant (MDR) Salmonella are important foodborne pathogens. E. coli O157:H7 is the most frequently isolated STEC serotype. Meanwhile, six non-O157 STEC serotypes have attracted significant attention from the scientific and regulatory fields lately since they have been associated with serious outbreaks as well, and will soon receive the same regulatory scrutiny as E. coli O157:H7 in the U.S. beef supply. It has been shown that STEC O157:H7 and Salmonella are capable of forming biofilms on food-contact surfaces that, when detached, may lead to cross-contamination. However, there are relatively few reports on non-O157 STEC biofilms and their resistance to sanitizers. This study evaluated the potency of biofilm formation by a variety of O157:H7 and non-O157 STEC strains, as well as MDR and non-MDR Salmonella strains. The data indicate that multiple factors, including bacterial serotype and strain, surface materials, and other environmental conditions, could significantly affect STEC and Salmonella biofilm formation. Compared to E. coli O157:H7, the non-O157 STEC biofilms exhibited higher sanitizer resistance that was associated with curli expression. In addition, bacterial coexistence and interactions significantly affected mixed biofilm development as STEC O26:H11 strains could effectively outgrow E. coli O157:H7 companion strains in both planktonic and biofilm phases, while the composition of dual-strain biofilms by STEC and Salmonella enterica was dependent on companion strain properties. Mixed biofilm formation by E. coli O157:H7, non-O157 STECs, and Salmonella strains also enhanced bacterial resistance to sanitization compared to the corresponding single-species biofilms. These results indicate the need for increased attention to the potential risk of biofilm contamination by foodborne pathogens, especially the non-O157 STECs, in food processing facilities.