Poster abstracts

Poster number 32 submitted by Shareef Dabdoub

Quantitative analysis and comparison of intracellular biofilms in E. coli induced cystitis

Shareef M Dabdoub (The Ohio State University Biophysics Program), Sheryl S. Justice (The Research Institute at Nationwide Childrens Hospital, Center for Microbial Pathogenesis), William C. Ray (The Ohio State University Biophysics Program)

Abstract:
Uropathogenic Escherichia coli (UPEC) cause recurrent urinary tract infections by establishing Intracellular Bacterial Communities (IBCs) that enable evasion of host immune responses. The lifecycle and development of an IBC can be divided into three phases with accompanying morphological changes. Specifically, UPEC begins as a bacillus, replicates into a coccoid form, and, as a large component of its evasion strategy, some members of the colony cease cell division, and adopt a multinucleated filamentous form. This form is able to resist phagocytosis, and provides the seed generation for perpetuating the infection after the host response subsides. However, little is known about the exact causes of these morphological changes, and how they might affect IBC formation, coherence, and pathogenicity. To aid in understanding the roles of these variables in cystitis, we have investigated two mutants in addition to the wild type UTI-89: the kpsF capsule mutant and the surA (outer membrane protein chaperone) mutant. Fluorescent microscopy of infected murine superficial bladder epithelial cells reveals visually compelling differences. However, quantitation is necessary to provide reproducible, comparable results. To this end, we have developed a tool for manually assisted annotation and identification of bacteria using 3D volume reconstruction of optical slices of infected murine bladders imaged by fluorescence microscopy. This tool provides the 3D spatial location and orientation of each bacterium within the IBC, allowing us to make quantitative and statistical analyses of community size, cohesion, and morphological makeup, as well as enabling comparison between the wild type UTI-89 and mutant IBCs. This tool will also enable enhanced quantitative analysis of general biofilms, allowing more accurate investigation of these important bacterial structures studied in many areas of infectious disease.

References:
Sheryl S. Justice et al., “Differentiation and developmental pathways of uropathogenic Escherichia coli in urinary tract pathogenesis,” Proceedings of the National Academy of Sciences of the United States of America 101, no. 5 (February 3, 2004): 1333-1338.

Sheryl S. Justice et al., “Maturation of Intracellular Escherichia coli Communities Requires SurA,” Infect. Immun. 74, no. 8 (August 1, 2006): 4793-4800.

Sheryl S Justice et al., “Filamentation by Escherichia coli subverts innate defenses during urinary tract infection,” Proceedings of the National Academy of Sciences of the United States of America 103, no. 52 (December 26, 2006): 19884-19889.

Keywords: volume visualization, E coli, biofilms