UC Merced

Antibiotic resistant infections are a public health threat. According to the CDC, the incidence of antibiotic resistant infections has increased 50% in the last five years1. Urinary tract infections (UTIs) are the most commonly occurring bacterial infection and resistance among them is highly prevalent. Lack of mandatory reporting of these infections, and a vast array of treatment options, place UTIs at the frontiers of newly evolved resistance. To investigate this important human health threat, I performed three studies. First, I performed a surveillance study of antibiotic resistance trends in uropathogenic E. coli (UPEC) at Dignity Health Mercy Medical Center (DHMMC) in Merced, and compared them to resistance trends found nationwide. I found higher incidence of resistance at DHMMC than nationwide. Second, to identify causes for this elevated resistance, I investigated potential environmental sources of antibiotic resistant infections at DHMMC. In doing so, I developed a rapid PCR screen for identifying UPEC using a suite of six genetic markers significantly associated with UPEC. Using this screen, I found evidence of UPEC in all environmental sites surveyed, most associated with livestock for retail meat. Third, to identify the fitness effects of antibiotic resistance genes upon bacteria being treated with antibiotics, and to further infer the effects of antibiotic consumption on the selection of the antibiotic resistance genes, I created a customizable plasmid vector construct library. This library contains all possible combinations of the four most identified resistance genes at DHMMC, and it can be used to evaluate their fitness, relative to one another, in the presence and absence of different antibiotics. In summary, I characterized the antibiotic resistance trends at DHMMC, identified potential sources of the resistance, and developed an experimental tool to evaluate the ongoing selection from antibiotic consumption resulting in the resistance trends at DHMMC.