Overview of Methodologies to Sample and Assess Microbial Burden in Low Biomass Environments

Abstract

The detection and evaluation of microbial contamination is the goal of many programs in the medical, food, pharmaceutical, and environmental monitoring/biothreat detection industries. Similarly, NASA's Planetary Protection program strives to assess, as well as prevent, microbial contamination in spacecraft assembly facilities and on spacecraft themselves. The development of improved methods and technologies designed to facilitate these common goals is therefore important. This review will focus on instrumentation and techniques currently being utilized or evaluated for use by the Planetary Protection program in the clean room environments of spacecraft assembly facilities. Current sampling technologies (novel sampling instrumentation and di#erent collection materials) were compared with NASA standard protocols under field and controlled conditions. A brief literature review was presented to augment the comparisons. Additionally, as the integrity of sample analyses is directly dependent on both the e$ciency of sample collection and the quality of sample processing, a novel nucleic acid extraction instrument was also evaluated. The impact of these new technologies will be discussed with respect to sample collection, processing, and analyses from the low biomass environments present in NASA clean rooms, although the findings may be applied in a broader context to other industries and programs as well as to the development of future integrated biosensors.

Validation of a Nylon-Flocked-Swab Protocol for Efficient Recovery of Bacterial Spores from Smooth and Rough Surfaces

“…Previous studies have compared cotton and synthetic sampling materials, but only on stainless steel surfaces (19), and no studies have compared sampling methods on actual spacecraft materials (7).…”

“…Furthermore, their comparatively high DNA content could lead to false positives or inhibition should NASA one day incorporate molecular technologies into their microbialdetection protocols (7).…”

Biomass and habitability potential of clay minerals- and iron-rich environments: Testing novel analogs for Mars Science Laboratory landing sites candidates

“…The LPS-based, or Gram-negative biomass in the rock and mineral samples was determined with a portable system (Charles River Laboratories PTS System Package 550 Õ ) based on the Limulus amebocyte lysate assay, or LAL [33]. This is an extremely sensitive non culture-based method to measure, in a relatively rapid and accurate manner, the amount of lipopolysaccarides, or LPS (aka the microbial endotoxin) in the environment.…”

Comprehensive Census of Bacteria in Clean Rooms by Using DNA Microarray and Cloning Methods

“…Samples were collected from the surfaces of various NASA SAC. Wet-surface sampling of the SAC floor (1 m 2 ) was performed using biological sampling kits (BiSKits; QuickSilver Analytics, Abingdon, MD) as previously described (4). Controls specific for each BiSKit were prepared in a class II biohood immediately prior to sampling.…”