Open AccessGrowth and Virulence Properties of Biofilm-Forming Salmonella enterica Serovar Typhimurium under Different Acidic Conditions
Author(s) -
Hua Xu,
Hyeon-Yong Lee,
Juhee Ahn
Publication year - 2010
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.01508-10
Subject(s) - biofilm , salmonella enterica , virulence , microbiology and biotechnology , tryptic soy broth , salmonella , serotype , incubation , biology , brain heart infusion , bacteria , viable count , enterobacteriaceae , chemistry , escherichia coli , agar , gene , biochemistry , genetics
This study was designed to characterize the viability and potential virulence of bofilm-formingSalmonella enterica serovar Typhimurium under different pH levels, ranging from 5 to 7. The plate count method and real-time reverse transcription-PCR (RT-PCR) were used to evaluate the survival ofS. Typhimurium grown in Trypticase soy broth (TSB) adjusted to pH 5, 6, and 7 (TSB-5, TSB-6, and TSB-7, respectively) at 37°C for 10 days. In TSB-5 and TSB-6, the numbers of viable cells estimated by using the real-time RT-PCR were greater than the culturable counts enumerated by the plate count method. Reflectance micro-Fourier transform infrared (micro-FTIR) spectroscopy was used to evaluate the biochemical changes in biofilm cells. Considerable changes in chemical components were observed in the biofilm cells grown in TSB-5 and TSB-6 when compared to the cells grown in TSB-7. The enterotoxin production and invasive ability of planktonic and biofilmS. Typhimurium cells were inferred by the relative levels of expression ofstn andinvA . The levels of expression ofstn andinvA were significantly increased in biofilmS. Typhimurium cells grown in TSB-5 (1.9-fold and 3.2-fold) and TSB-6 (2.1-fold and 22.3-fold) after 10 days of incubation. These results suggest that the biofilm-formingS . Typhimurium under different pH levels might change the virulence production and stress response mechanisms.