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Development of a Rapid Method for Detection and Differentiation of Escherichia coli Serotypes and Strains Using Attenuated Total Reflectance Fourier Transform Infrared Microspectroscopy

Cook, Crystal N
http://rave.ohiolink.edu/etdc/view?acc_num=osu1461253150

Abstract Details

2016, Master of Science, Ohio State University, Food Science and Technology.
Escherichia coli is a common bacterium found in the intestinal tract of all mammals, environment, and foods. Pathogenic E. coli cause many outbreaks, hospitalizations, and deaths with Shiga toxin-producing E. coli (STEC) O157 being the leading source of foodborne outbreaks in the United States of America. Both STEC O157 and STEC non-O157 (e.g. O26, O45, O103, O111, O121, and O145) create millions of dollars of economic burden due to treatment costs and productivity losses. Currently, detection and identification of pathogenic E. coli is dependent on time consuming, labor intensive procedures that often require a trained employee to perform. Today’s food industry needs a rapid, sensitive, and accurate method for detecting and identifying E. coli strains. Mid infrared spectroscopy is an easy-to-use, rapid detection technique that measures the molecular vibrations of atoms within a molecule producing unique spectral patterns or fingerprints. Furthermore, infrared microspectroscopy (IRMS) improves the sensitivity, reproducibility, differentiation, and speed capabilities of IR spectroscopy by coupling an infinity-corrected microscope to a high performance IR spectrometer. IRMS can provide capabilities for high-throughput screening of microorganisms and the ability to resolve spectral profiles within desired regions of the target. The objective of this study was to develop a rapid method for identification and differentiation of E. coli strains using IRMS and chemometrics. The E. coli strains were generously provided by Dr. Joshua Daniels of the Department of Veterinary Clinical Sciences at The Ohio State University (Columbus, OH). E. coli strains (15) from 3 different serotypes were grown on tryptic soy agar (TSA) plates at 37°C for 24 hours. Bacteria cells were immersed into 100% ethanol (to enhance safe handling of the pathogenic bacteria), rinsed twice with water, transferred to a NEO-GRID membrane, vacuum dried, and analyzed directly by an IR microspectrometer. An attenuated total reflectance (ATR) germanium crystal was used to collect spectra in the 4000 cm-1 to 700 cm-1 range, and to increase the signal to noise ratio, 128 scans were co-added during collection of the spectra. Bacterial spectra were collected on 4 to 5 different days with 10-15 spectral measurements per day. Soft independent modeling of class analogy (SIMCA) (a supervised, classification technique) was employed to cluster E. coli strains and predict class membership for new additions. E. coli strains exhibited distinctive and reproducible infrared spectra in the fingerprint region (1500-900 cm-1) of the IR spectrum. SIMCA permitted distinguishing E. coli strains through differences in bacterial cell envelope components. IRMS combined with chemometrics provide a simple and rapid phenotypic procedure for the reliable identification of E. coli strains and it could be potentially useful for an efficient and reliable monitoring of bacterial contamination in food with minimal sample manipulation.
Luis Rodriguez-Saona (Advisor)
Lynn Knipe (Committee Member)
Ahmed Yousef (Committee Member)
56 p.
Food Science; Microbiology

Recommended Citations

Citations

  • Cook, C. N. (2016). Development of a Rapid Method for Detection and Differentiation of Escherichia coli Serotypes and Strains Using Attenuated Total Reflectance Fourier Transform Infrared Microspectroscopy [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461253150

    APA Style (7th edition)

  • Cook, Crystal. Development of a Rapid Method for Detection and Differentiation of Escherichia coli Serotypes and Strains Using Attenuated Total Reflectance Fourier Transform Infrared Microspectroscopy. 2016. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1461253150.

    MLA Style (8th edition)

  • Cook, Crystal. "Development of a Rapid Method for Detection and Differentiation of Escherichia coli Serotypes and Strains Using Attenuated Total Reflectance Fourier Transform Infrared Microspectroscopy." Master's thesis, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461253150

    Chicago Manual of Style (17th edition)

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