tailieunhanh - Salmonella A Dangerous Foodborne Pathogen Part 8

Tham khảo tài liệu 'salmonella a dangerous foodborne pathogen part 8', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 164 Salmonella - A Dangerous Foodborne Pathogen The persistence of Salmonella within the food chain has become a major health concern as biofilms of this pathogen formed in food processing environments can serve as a reservoir for the contamination of food products. The development of materials to be used for foodcontact surfaces with improved food safety profiles continues to be a challenge. One approach which has been developed to control microbial attachment is the manufacture of food-contact materials incorporating antimicrobial compounds. Triclosan-impregnated kitchen bench stones silestones although prone to bacterial colonization were found to reduce S. Enteritidis biofilm development on them and also the viability of cells within the biofilm Rodrigues et al. 2011 . 5. Molecular components of Salmonella biofilms formed on abiotic surfaces Curli fimbriae formerly designated as thin aggregative fimbriae or Tafi and cellulose are the two main matrix components exopolymeric substances EPS in Salmonella biofilms Gerstel Romling 2003 . When co-expressed on Congo Red CR agar plates curli fimbriae and the exopolysaccharide cellulose form the characteristic rdar red dry and rough morphotype also called rugose or wrinkled Romling 2005 . Their syntheses are co-regulated by a complex regulatory system. The LuxR type regulator CsgD protein stimulates the production of curli through transcriptional activation of the csgBAC formerly agfBAC operon while the activation of cellulose production is indirect through the regulator AdrA which is a member of the GGDEF protein family regulated by csgD Romling et al. 2000 . García et al. 2004 demonstrated that most GGDEF proteins of S. Typhimurium are functionally related probably by controlling the levels of the same final product cyclic di-GMP a secondary messenger that seems to regulate a variety of cellular functions including cellulose production and biofilm formation. The co-expression of curli fimbriae and cellulose leads to .