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Characterization of Microbial Contaminants Associated with Floor Material Types

Gupta, Mridula
http://rave.ohiolink.edu/etdc/view?acc_num=osu1483636606986462

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Public Health.
People spend a major part of their time indoors, including time spent at their workplace and residence. Indoor environmental quality plays a vital role contributing to human health and wellbeing. Part of the indoor environment is flooring. Although the type of flooring material has been regarded to be an influencing factor for indoor air quality, there is a dearth of studies comparing the contribution of several flooring types in environmental contamination. The primary goal of this dissertation was to compare the various floor materials and their potential contribution to fate of environmental microbial contaminants. To achieve this goal, studies were designed to determine: a) the most efficient surface sampling method to estimate microbiological composition; b) Survivability of S. aureus and spores of A. niger on five common floor materials; c) Survivability of soil microbes on two common floor materials. and d) Bacterial microbiome analysis of floor samples in three buildings. Comparison of three surface sampling methods on five floor materials found that the bulk-rinsate sampling method was the most sensitive and efficient method to quantify microbial contaminants from floor surfaces. The bulk-rinsate method uses the entire floor sample material and thus measures total biocontaminants associated with the floor surface. Five floor materials (commercial carpet, residential carpet, vinyl tile, wood, and porcelain tile) were inoculated with known bacteria (Staphylococcus aureus) and fungi (Aspergillus niger) as well as composite of microbes (bacteria and fungi) extracted from soil for survivability studies. Carpets both residential and rubber backed commercial showed a decline in survivability of both S. aureus and spores of A. niger in the absence of nutrition. While in the presence of additional nutrient (simulated in-use) S. aureus showed growth on carpets. In addition, A. niger spores which completely disappeared without nutrition, was viable up to day 28 in the presence of nutrition. Hard surface floor materials -- vinyl, wood and porcelain-- had similar survivability patterns of both S. aureus and spores of A. niger. Both S. aureus and spores of A. niger had higher and longer survivability on vinyl in the presence of additional nutrient. This additional nutrient (Nutrient broth and 1XPBS) was a simulation for in-use condition and represents the potential of floor surfaces, especially if labile nutrient sources are present, to sustain microbial growth. Similar results were obtained with bacteria and fungi from soil inoculate. Soil bacteria on both carpets and floors survived for day 28. Microbiome analysis for bacterial composition of actual in use floor materials was carried out using surface samples from floors located in a human hospital, a veterinary hospital and an office. Culture independent next generation sequencing was performed to identify the bacterial composition. The bacterial composition of the carpets and vinyl floors did not differ statistically. Both floor samples had bacterial composition enriched with soil bacteria. Proteobateria was the major phylum on all the floors. The composition also did not differ between the three buildings. However, traffic patterns were found to be significant for the Operational Taxonomic Unit (OTU) level. Higher traffic area had higher OTUs as well as high number of antibiotic resistance gene (tetQ) copies per floor sample. The studies conducted to fulfill the requirements for this dissertation attempted to fill in the knowledge gap of survivability of bacteria and fungi on various environmental surfaces, such as floors. The survivability of clinically important bacteria and fungi for four weeks on floors may contribute significantly to environmental contribution Finally, as evident from the study, floors surfaces could be enriched with soil microbes containing pathogenic bacteria and antibiotic resistance organisms which pose a significant public health risk.
Michael Bisesi (Advisor)
Jiyoung Lee (Committee Member)
Mac Crawford (Committee Member)
Judith Schwartzbaum (Committee Member)
139 p.
Environmental Health

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Citations

  • Gupta, M. (2017). Characterization of Microbial Contaminants Associated with Floor Material Types [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483636606986462

    APA Style (7th edition)

  • Gupta, Mridula. Characterization of Microbial Contaminants Associated with Floor Material Types . 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1483636606986462.

    MLA Style (8th edition)

  • Gupta, Mridula. "Characterization of Microbial Contaminants Associated with Floor Material Types ." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483636606986462

    Chicago Manual of Style (17th edition)

osu1483636606986462
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This open access ETD is published by The Ohio State University and OhioLINK.