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Effects of community composition and growth rate on aquifer biofilm bacteria and their susceptibility to betadine disinfection
Author(s) -
Whiteley Marvin,
Ott James R.,
Weaver Eric A.,
McLean Robert J. C.
Publication year - 2001
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1046/j.1462-2920.2001.00158.x
Subject(s) - biofilm , biology , microbiology and biotechnology , pseudomonas putida , population , bacteria , disinfectant , chemistry , genetics , demography , organic chemistry , sociology
Biofilm formation and function was studied in mixed culture using 20 bacterial strains isolated from a karst aquifer. When co‐cultured in a glucose‐limited chemostat, Vogesella indigofera and Pseudomonas putida were the dominant planktonic and biofilm organisms respectively. Biofilm formation and resistance to the iodine disinfectant betadine were then studied with monoculture and binary cultures of V. indigofera and P. putida and a 20‐strain community. Biofilm population size [measured as colony‐forming units (CFU) cm −2 ] increased with increasing species diversity. Significantly larger populations formed at dilution rates (DRs) of 0.0083 h −1 than at 0.033 h −1 . P. putida populations were higher and V. indigofera lower in binary than in monoculture biofilms, suggesting that P. putida outcompeted V. indigofera . In binary biofilms, V. indigofera , a betadine‐resistant organism, enhanced the survival of P. putida , a betadine‐susceptible organism. In the 20‐strain biofilms, this protective effect was not observed because of low concentrations of V. indigofera (< 1% of the total population), suggesting that resistant organisms contribute to overall biofilm disinfectant resistance. Growth at 0.033 h −1 enhanced survival of V. indigofera biofilms against betadine. Although DR did influence survival of the other communities, its effects were neither consistent nor significant. All told, biofilm formation and betadine resistance are complex phenomena, influenced by community composition, growth rate and betadine concentration.