Date of Award
Master of Science
Food Science and Human Nutrition
Food Science and Technology
Clostridium difficile infection (CDI) causes roughly 30,000 deaths each year in the United States and the number has been increasing since the early 2000s. Traditionally, CDI is treated with antibiotics (metronidazole or vancomycin). However, this method is only effective in 50% of the patients since it only affects the vegetative C. difficile cells and not the spores. Since the early 2000s fecal microbiota transplants (FMTs) have been used as a treatment method, leading to over 80% success rate. However, FMTs are still considered an investigational therapy since the mechanism of how these FMTs treat CDI are unknown. This has led to research into probiotics as a possible treatment method. In this study, the objectives were to identify major bacteria species common across 20 FMTs, and investigate if some of these bacteria could be potential probiotics. Our secondary focus was to evaluate microorganisms found in kefir, for effectiveness against C. difficile. Bacterodies and Ruminococcaceae were found to be the most prevalent bacteria family across the 20 FMTs. Potentially probiotic Lactobacillus and Bifidobacterium only made up roughly 0.2% of the bacteria population. The kefir and the different kefir components (cell-free supernatant, cell lysate, fat) inhibition capabilities were tested against C. difficile. It was found that neither the different components nor the entire kefir matrix showed any inhibition against C. difficile. However, a Lactobacillus paracasei isolate was found to not only grow alongside C. difficile, but to have resistance against the antibiotic vancomycin, making it a potential candidate for competitive inhibition against C. difficile. L. paracasei showed little inhibition when inoculated at the same population concentration as the C. difficile and also did not significantly inhibit C. difficile growth when used at a higher population concentration.
Choquette, Kelsey, "Evaluating the effectiveness of select bacteria against Clostridium difficile" (2017). Graduate Theses and Dissertations. 15281.