Laboratory Model for Formation of Heterogeneous Biofilms on Galvanized Iron and Survival of A. hydrophila

Zarine Bhathena and Beryleen Victor

Department of Microbiology, Bhavan's College, Andheri, Mumbai 400 058

DOI : http://dx.doi.org/http://dx.doi.org/10.13005/bbra/1551

ABSTRACT:

Biofilms are composite highly hydrated structures of microbial cells that have implications in mass and energy transfer in aquatic ecosystems. Entry of potential pathogens and its concomitant shedding from the biofilm consortia formed on pipeline materials pose a grave threat to the quality of drinking water obtained by a community. A lab scale model biofilm consisting of heterotrophic micro flora from Mumbai water supply was developed on galvanized iron pipe pieces and entry of an emerging pathogen A. hydrophila isolate B8 studied using viable count techniques. Scanning Electron Microscopy and FT-IR spectroscopy was undertaken to assess the formation of rudimentary glycocalyx which enable the bacterial cells to adhere on to substratum while confocal laser scanning microscopy was used to observe the depth of the biofilm attained with progression of time. A stable heterotrophic biofilm from the autochthonous organisms present in the drinking waters supplied by Bhandup Municipal treatment plant to Mumbai city was attained within 16 days and A. hydrophila was able to enter the biofilm to become an integral part of the community within 2 days indicating that presence of pathogens in supplied drinking waters may not just be due to failure of water treatment plants but through preexisting biofilms on pipeline materials

KEYWORDS: Biofilms; A. hydrophila; Confocal Scanning Laser Microscopy; Scanning Electron Microscopy; Fourier Transform Infrared spectra .

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