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Removal of Burkholderia cepacia biofilms with oxidants
Author and Affiliation:
Koenig, D. W.(NASA Johnson Space Center, Houston TX United States)
Mishra, S. K.
Pierson, D. L.
Abstract: Iodine is used to disinfect the water system aboard US space shuttles and is the anticipated biocide for the international space station. Water quality on spacecraft must be maintained at the highest possible levels for the safety of the crew. Furthermore, the treatment process used to maintain the quality of water on research must be robust and operate for long periods with minimal crew intervention. Biofilms are recalcitrant and pose a major threat with regard to chronic contamination of spacecraft water systems. We measured the effectiveness of oxidizing biocides on the removal and regrowth of Burkholderia (Pseudomonas) cepacia biofilms. B. cepacia, isolated from the water distribution system of the space shuttle Discovery, was grown in continuous culture to produce a bacterial contamination source for biofilm formation and removal studies. A 10(7) CFU ml-1 B. cepacia suspension, in distilled water, was used to form biofilms on 3000 micrometers2 glass surfaces. Rates of attachment were measured directly with image analysis and were found to be 7.8, 15.2, and 22.8 attachment events h-1 for flow rates of 20.7, 15.2, and 9.8 ml min-1, respectively. After 18 h of formation, the B. cepacia biofilms were challenged with oxidants (ozone, chlorine, and iodine) and the rates of biofilm removal determined by image analysis. Fifty percent of the biofilm material was removed in the first hour of continous treatment with 24 mg l-1 chlorine or 2 mg l-1 ozone. Iodine (48 mg l-1) did not remove any measurable cellular material after 6 h continuous contact. After this first removal of biofilms by the oxidants, the surface was allowed to refoul and was again treated with the biocide. Iodine was the only compound that was unable to remove cellular debris from either primary or secondary biofilms. Moreover, treating primary biofilms with iodine increased the rate of formation of secondary biofilms, from 4.4 to 5.8 attachment events h-1. All the oxidants tested inactivated the B. cepacia associated with both primary and secondary biofilms. The amount of biocide needed to inactivate 50% of planktonic B. cepacia in 10 min at 25 degrees C was 8.4, 0.5, and 0.2 mg l-1 for iodine, chlorine, and ozone, respectively. The data suggest that iodine maynot be the best chemical for treating of biofilms when removal of cellular material is required.
Publication Date: Jan 01, 1995
Document ID:
20040089290
(Acquired Sep 07, 2004)
Subject Category: LIFE SCIENCES (GENERAL)
Document Type: Journal Article
Publication Information: Biofouling (ISSN 0892-7014); Volume 9; 1; 51-62
Publisher Information: Switzerland
Financial Sponsor: NASA Johnson Space Center; Houston TX United States
Description: In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ANTISEPTICS; BACTERIA; BIOFILMS; CHLORINE; IODINE; OXIDIZERS; OZONE; EVALUATION; MICROBIOLOGY; WATER TREATMENT
Other Descriptors: BIOFILMS/DRUG EFFECTS/GROWTH & DEVELOPMENT; BURKHOLDERIA CEPACIA/DRUG EFFECTS/GROWTH & DEVELOPMENT; CHLORINE/PHARMACOLOGY; DISINFECTANTS/PHARMACOLOGY; IODINE/PHARMACOLOGY; OXIDANTS, PHOTOCHEMICAL/PHARMACOLOGY; OZONE/PHARMACOLOGY; BACTERIAL ADHESION/PHYSIOLOGY; COLONY COUNT, MICROBIAL; COMPARATIVE STUDY; EVALUATION STUDIES; SPACE FLIGHT/INSTRUMENTATION; SUPPORT, U.S. GOV'T, NON-P.H.S; WATER MICROBIOLOGY; WATER PURIFICATION/METHODS; NASA CENTER JSC; NASA DISCIPLINE ENVIRONMENTAL HEALTH
Availability Source: Other Sources
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