Abstract
Established (48- and 72-h) Salmonella enteritidis biofilms grown in glass flow cells with or without artificial crevices (0.5-, 0.3-, and 0.15-mm widths) were subjected to a 10% trisodium phosphate (TSP) solution under different flow regimens (0.3, 0.6, 1.2, and 1.8 cm s-1). The abundance of biofilm remaining after TSP treatment, the biocidal efficacy of TSP, and the factors which contributed to bacterial survival were then evaluated by using confocal laser microscopy and a fluorescent viability probe. Biofilm age affected the amount of biofilm which remained following a 15-s exposure to TSP. After TSP treatment of 48-h biofilms, 29% of the original biofilm remained at the biofilm-liquid interface, whereas 75% of the biofilm remained at the base (the attachment surface). Following TSP treatment of 72-h biofilms, 27% of the biofilm material remained at the biofilm-liquid interface, 73% remained at the 5-micron depth, and 91% remained at the biofilm base. Results obtained using the BacLight viability probe indicated that TSP exposure killed all the cells in 48-h biofilms, whereas in the thicker 72-h biofilms, surviving bacteria (approximately 2% of the total) were found near the 5- and 0-micron depths. In the presence of artificially constructed crevices, an inverse relationship was shown to exist between bacterial survival (ranging from approximately 13 to 83% of total biofilm material) and crevice width. This relationship was further influenced by the velocity of TSP flow; high TSP flow velocities (1.8 cm s-1) resulted in the lowest number of surviving bacteria at the base of crevices (approximately 42% survival). Extended time courses demonstrated that after TSP stress was relieved, biofilms continued to grow within crevices but not in systems without crevices. It is suggested that advective TSP flux into crevices and through the biofilm matrix was enhanced under conditions of high flow. These results suggest that the inherent roughness of the substratum on which the biofilm was grown and the timing of TSP application are important factors controlling the efficacy of TSP treatment.
Full Text
The Full Text of this article is available as a PDF (1.4 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brown M. R., Allison D. G., Gilbert P. Resistance of bacterial biofilms to antibiotics: a growth-rate related effect? J Antimicrob Chemother. 1988 Dec;22(6):777–780. doi: 10.1093/jac/22.6.777. [DOI] [PubMed] [Google Scholar]
- Costerton J. W., Lewandowski Z., Caldwell D. E., Korber D. R., Lappin-Scott H. M. Microbial biofilms. Annu Rev Microbiol. 1995;49:711–745. doi: 10.1146/annurev.mi.49.100195.003431. [DOI] [PubMed] [Google Scholar]
- Costerton J. W., Lewandowski Z., DeBeer D., Caldwell D., Korber D., James G. Biofilms, the customized microniche. J Bacteriol. 1994 Apr;176(8):2137–2142. doi: 10.1128/jb.176.8.2137-2142.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dewanti R., Wong A. C. Influence of culture conditions on biofilm formation by Escherichia coli O157:H7. Int J Food Microbiol. 1995 Jul;26(2):147–164. doi: 10.1016/0168-1605(94)00103-d. [DOI] [PubMed] [Google Scholar]
- Foster J. W., Spector M. P. How Salmonella survive against the odds. Annu Rev Microbiol. 1995;49:145–174. doi: 10.1146/annurev.mi.49.100195.001045. [DOI] [PubMed] [Google Scholar]
- Gilbert P., Collier P. J., Brown M. R. Influence of growth rate on susceptibility to antimicrobial agents: biofilms, cell cycle, dormancy, and stringent response. Antimicrob Agents Chemother. 1990 Oct;34(10):1865–1868. doi: 10.1128/aac.34.10.1865. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Korber D. R., Choi A., Wolfaardt G. M., Caldwell D. E. Bacterial plasmolysis as a physical indicator of viability. Appl Environ Microbiol. 1996 Nov;62(11):3939–3947. doi: 10.1128/aem.62.11.3939-3947.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Korber D. R., James G. A., Costerton J. W. Evaluation of Fleroxacin Activity against Established Pseudomonas fluorescens Biofilms. Appl Environ Microbiol. 1994 May;60(5):1663–1669. doi: 10.1128/aem.60.5.1663-1669.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lawrence J. R., Korber D. R., Hoyle B. D., Costerton J. W., Caldwell D. E. Optical sectioning of microbial biofilms. J Bacteriol. 1991 Oct;173(20):6558–6567. doi: 10.1128/jb.173.20.6558-6567.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LeChevallier M. W., Cawthon C. D., Lee R. G. Factors promoting survival of bacteria in chlorinated water supplies. Appl Environ Microbiol. 1988 Mar;54(3):649–654. doi: 10.1128/aem.54.3.649-654.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LeChevallier M. W., Hassenauer T. S., Camper A. K., McFeters G. A. Disinfection of bacteria attached to granular activated carbon. Appl Environ Microbiol. 1984 Nov;48(5):918–923. doi: 10.1128/aem.48.5.918-923.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nichols W. W., Dorrington S. M., Slack M. P., Walmsley H. L. Inhibition of tobramycin diffusion by binding to alginate. Antimicrob Agents Chemother. 1988 Apr;32(4):518–523. doi: 10.1128/aac.32.4.518. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Somers E. B., Schoeni J. L., Wong A. C. Effect of trisodium phosphate on biofilm and planktonic cells of Campylobacter jejuni, Escherichia coli O157: H7, Listeria monocytogenes and Salmonella typhimurium. Int J Food Microbiol. 1994 Jun;22(4):269–276. doi: 10.1016/0168-1605(94)90178-3. [DOI] [PubMed] [Google Scholar]
- Stoodley P., Debeer D., Lewandowski Z. Liquid flow in biofilm systems. Appl Environ Microbiol. 1994 Aug;60(8):2711–2716. doi: 10.1128/aem.60.8.2711-2716.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thomson J. E., Bailey J. S., Cox N. A. Phosphate and heat treatments to control Salmonella and reduce spoilage and rancidity on broiler carcasses. Poult Sci. 1979 Jan;58(1):139–143. doi: 10.3382/ps.0580139. [DOI] [PubMed] [Google Scholar]
- Wolfaardt G. M., Lawrence J. R., Robarts R. D., Caldwell S. J., Caldwell D. E. Multicellular organization in a degradative biofilm community. Appl Environ Microbiol. 1994 Feb;60(2):434–446. doi: 10.1128/aem.60.2.434-446.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]