Year

2020

Season

Fall

Paper Type

Master's Thesis

College

College of Arts and Sciences

Degree Name

Master of Science in Biology (MS)

Department

Biology

NACO controlled Corporate Body

University of North Florida. Department of Biology

First Advisor

Terri N. Ellis

Second Advisor

Judith Ochrietor

Third Advisor

Matthew Gilg

Abstract

Klebsiella pneumoniae is a Gram-negative bacterium responsible for nosocomial infections such as blood stream infections, meningitis, and septicemia. Clinical isolates confirm K. pneumoniae is increasingly antibiotic resistant (AR) making treatment more difficult. While bacterial exposure to antimicrobial substances is a known cause of the AR phenotype, there still exists gaps in knowledge about the genetic changes responsible for this fitness change. The laboratory Klebsiella pneumoniae 43816 (ATCC 43816) was exposed to sublethal concentrations of Cephalothin for a 14-day period. At the end of the experimental treatment, the adapted population acquired clinical antibiotic resistance along with phenotypic and morphological changes. The goal of this study is to identify and characterize genetic mutations which correlate to increases in antibiotic resistance and morphological changes in the adapted K. pneumoniae population. DNA was extracted and sequenced from the adapted bacteria and a population subcultured for 14 days without exposure to antibiotic. Comparison of these sequences to the known ATCC 43816 genome identified eight mutations unique to the adapted culture in seven protein coding regions. Results also found 6 putative promoter regions with mutations in the adapted culture. The data confirm that fixed changes in genotype are correlated with the altered phenotype. Additionally, findings suggest that the development of resistance may involve genes not previously known for β-lactamase function in Klebsiella pneumoniae and that the exact mechanism used to overcome antibiotic exposure is not uniform within a treated population.

Available for download on Saturday, December 10, 2022

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