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Rapid in situ assessment of physiological activities in bacterial biofilms using fluorescent probesTwo rapid in situ enumeration methods using fluorescent probes were used to assess the physiological activities of Klebsiella pneumoniae biofilms on stainless steel. Fluorescent dyes, 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and rhodamine 123 (Rh 123), were chosen to perform this study. CTC is a soluble redox indicator which can be reduced by respiring bacteria to fluorescent CTC-formazan crystals. Rh 123 is incorporated into bacteria with respect to cellular proton motive force. The intracellular accumulation of these fluorescent dyes can be determined using epifluorescence microscopy. The results obtained with these two fluorescent probes in situ were compared to the plate count (PC) and in situ direct viable count (DVC) methods. Viable cell densities within biofilms determined by the three in situ methods were comparable and always showed approximately 2-fold higher values than those obtained with the PC method. As an additional advantage, the results were observed after 2 h, which was shorter than the 4 h incubation time required for the DVC method and 24 h for colony formation. The results indicate that staining with CTC and Rh 123 provides rapid information regarding cell numbers and physiological activities of bacteria within biofilms.
Document ID
20040089250
Acquisition Source
Johnson Space Center
Document Type
Reprint (Version printed in journal)
Authors
Yu, F. P.
(Montana State University Bozeman 59717)
McFeters, G. A.
Date Acquired
August 21, 2013
Publication Date
January 1, 1994
Publication Information
Publication: Journal of microbiological methods
Volume: 20
ISSN: 0167-7012
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAG9-241
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 04-10
Non-NASA Center
NASA Discipline Environmental Health

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