title: Evidence of pathogenic microbes in the International Space Station drinking water: reason for concern?
abstract: Molecular analyses were carried out on four preflight and six postflight International Space Station (ISS)-associated potable water samples at various stages of purification, storage, and transport, to ascertain their associated microbial diversities and overall microbial burdens. Following DNA extraction, PCR amplification, and molecular cloning procedures, rDNA sequences closely related to pathogenic species of Acidovorax, Afipia, Brevundimonas, Propionibacterium, Serratia, and others were recovered in varying abundance. Retrieval of sequences arising from the iodine (biocide)-reducing Delftia acidovorans in postflight waters is also of concern. Total microbial burdens of ISS potable waters were derived from data generated by an ATP-based enumeration procedure, with results ranging from 0 to 4.9 x 10(4) cells/ml. Regardless of innate biases in sample collection and analysis, such circumstantial evidence for the presence of viable, intact pathogenic cells should not be taken lightly. Implementation of new cultivation approaches and/or viability-based assays are requisite to confirm such an occurrence.
authors.affiliation: Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. mtladuc@jpl.nasa.gov
authors.forename: Myron T
authors.initials: MT
authors.lastname: La Duc
authors.forename: Randall
authors.initials: R
authors.lastname: Sumner
authors.forename: Duane
authors.initials: D
authors.lastname: Pierson
authors.forename: Parth
authors.initials: P
authors.lastname: Venkat
authors.forename: Kasthuri
authors.initials: K
authors.lastname: Venkateswaran
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D001681:Biological Assay; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000032:analysis; D007455:Iodine / Q000494:pharmacology; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D013026:Space Flight; D018531:Spacecraft; D014871:Water Microbiology; D014881:Water Supply / Q000032:analysis; D014893:Weightlessness
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D007455:Iodine