Tomas Bermudez

Tomas Bermudez

PI: Maria Hadjifrangiskou, PhD, Department of Pathology, Microbiology & Immunology

Utilizations of Uropathogenic E. coli Transposon Library to Identify Oxygen-Dependent Biofilm Regulators

Urinary Tract Infections (UTIs) are one of the most common infections in the world today. One in two women will develop a UTI in their lifetime, and approximately one in five of those infected will have a recurrent infection. The most common culprit, Uropathogenic Escherichia coli (UPEC), causes an estimated 80% of all UTIs. UPEC is a Gram-negative facultative anaerobe that can form multicellular communities known as biofilms on and within bladder epithelial cells, as well as on catheter material. Within a biofilm, bacteria inhibit incoming stressors such as antibiotics from piercing their biomass, as well as allow for the exchange of nutrients within the colony. We have previously reported that gradually decreasing the oxygen concentration corresponds to decreased levels of UPEC biofilm formation. To identify oxygen-dependent regulators of biofilm formation, we created a saturated transposon library in cystitis isolate UTI89. We are screening for mutants that form abnormal biofilms under ambient (21% O2), hypoxic (4% O2), and anoxic (0% O2) conditions. To date, we have screened ~2,500 transposon mutants for biofilm formation at and are utilizing the Vanderbilt High-Throughput Screening core data analysis tools to identify clones of interest. Genomic DNA from the clones of interest will be being isolated and sequenced to identify the gene(s) responsible for the observed phenotypes. Further characterization of the identified genes will provide a molecular basis for the role of oxygen-dependent regulators in biofilm formation.