Rapid Detection of Bacteria in Spacecraft Water Systems

Pyle, Barry H.; Lisle, John T.; Broadaway, Susan C.; McFeters, Gordon A.

doi:10.4271/972421

Cited by 4 publications

(2 citation statements)

References 53 publications

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“…Burkholderia cepacia biofilms formed on the space shuttle Atlantis had up to twofold higher viable counts compared to the controls on Earth (26). Thus, the biofilms formed under LSMMG in our system duplicated an aspect of actual microgravity biofilms, further indicating the suitability of our system for ground-based studies of biofilm biology in microgravity.…”

mentioning

confidence: 62%

Escherichia coli Biofilms Formed under Low-Shear Modeled Microgravity in a Ground-Based System

Lynch

Mukundakrishnan

Benoit

et al. 2006

Appl Environ Microbiol

122

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Bacterial biofilms cause chronic diseases that are difficult to control. Since biofilm formation in space is well documented and planktonic cells become more resistant and virulent under modeled microgravity, it is important to determine the effect of this gravity condition on biofilms. Inclusion of glass microcarrier beads of appropriate dimensions and density with medium and inoculum, in vessels specially designed to permit ground-based investigations into aspects of low-shear modeled microgravity (LSMMG), facilitated these studies. Mathematical modeling of microcarrier behavior based on experimental conditions demonstrated that they satisfied the criteria for LSMMG conditions. Experimental observations confirmed that the microcarrier trajectory in the LSMMG vessel concurred with the predicted model. At 24 h, the LSMMG Escherichia coli biofilms were thicker than their normal-gravity counterparts and exhibited increased resistance to the general stressors salt and ethanol and to two antibiotics (penicillin and chloramphenicol). Biofilms of a mutant of E. coli, deficient in s , were impaired in developing LSMMG-conferred resistance to the general stressors but not to the antibiotics, indicating two separate pathways of LSMMG-conferred resistance.

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mentioning

confidence: 62%

Escherichia coli Biofilms Formed under Low-Shear Modeled Microgravity in a Ground-Based System

Lynch

Mukundakrishnan

Benoit

et al. 2006

Appl Environ Microbiol

122

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“…In the event of an outbreak, rapid methods can improve the probability of identifying the source and, ultimately, controlling the spread of infections. Other examples include the monitoring of spacecraft water prior to launch (23) and the examination of military environments for possible biological warfare agents. The use of more rapid methods for confirmation, including immunomagnetic separation (IMS) and fluorescent-antibody (FAb) identification, has become more common in the last several years (9,10,12,15,24,25,31,35).…”

mentioning

confidence: 99%

Sensitive Detection of Escherichia coli O157:H7 in Food and Water by Immunomagnetic Separation and Solid-Phase Laser Cytometry

Pyle

Broadaway

McFeters

1999

Appl Environ Microbiol

Self Cite

139

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Rapid, direct methods are needed to assess active bacterial populations in water and foods. Our objective was to determine the efficiency of bacterial detection by immunomagnetic separation (IMS) and the compatibility of IMS with cyanoditolyl tetrazolium chloride (CTC) incubation to determine respiratory activity, using the pathogenEscherichia coli O157:H7. Counterstaining with a specific fluorescein-conjugated anti-O157 antibody (FAb) following CTC incubation was used to allow confirmation and visualization of bacteria by epifluorescence microscopy. Broth-grown E. coli O157:H7 was used to inoculate fresh ground beef (<17% fat), sterile 0.1% peptone, or water. Inoculated meat was diluted and homogenized in a stomacher and then incubated with paramagnetic beads coated with anti-O157 specific antibody. After IMS, cells with magnetic beads attached were stained with CTC and then an anti-O157 antibody-fluorescein isothiocyanate conjugate and filtered for microscopic enumeration or solid-phase laser cytometry. Enumeration by laser scanning permitted detection of ca. 10 CFU/g of ground beef or <10 CFU/ml of liquid sample. With inoculated meat, the regression results for log-transformed respiring FAb-positive counts of cells recovered on beads versus sorbitol-negative plate counts in the inoculum were as follows: intercept = 1.06, slope = 0.89, andr 2 = 0.95 (n = 13). The corresponding results for inoculated peptone were as follows: intercept = 0.67, slope = 0.88, andr 2 = 0.98 (n = 24). Recovery of target bacteria on beads by the IMS-CTC-FAb method, compared with recovery by sorbitol MacConkey agar plating, yielded greater numbers (beef, 6.0 times; peptone, 3.0 times; water, 2.4 times). Thus, within 5 to 7 h, the IMS-CTC-FAb method detected greater numbers of E. coli O157 cells than were detected by plating. The results show that the IMS-CTC-FAb technique with enumeration by either fluorescence microscopy or solid-phase laser scanning cytometry gave results that compared favorably with plating following IMS.

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