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Publication Date

2024-5

First Advisor

Christine A. White-Ziegler

Document Type

Honors Project

Degree Name

Bachelor of Arts

Department

Biological Sciences

Keywords

biofilm, UPEC, CFT073, probiotics, oxygen, aerobic conditions, urinary tract infections, UTI treatments

Abstract

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (Eberly et al., 2017), which can be challenging to treat due to antibiotic resistance. This is due to UPEC forming robust biofilms that colonize bladder epithelial cells and catheters (Eberly et al., 2017). Bacteria have developed complex mechanisms to sense environmental changes and use these to respond and adapt to different niches. This study examines how changes in temperature, oxygen levels, incubation method, and environmental cues, which might change in the bladder, impact biofilm formation. I utilized the UPEC strain CFT073 and, as a comparison, the probiotic strain EcN and the biofilm-former non-pathogenic E.coli strain AR3110, at two different temperatures (23°C and 37°C). Because urine is high in amino acids, yeast extract and casamino acids (YESCA) were used as the growth medium. A key finding shows UPEC's temperature-dependent biofilm formation at 37°C under both anaerobic and aerobic conditions, particularly on specific substrates, with UPEC displaying enhanced biofilm formation at anaerobic compared to aerobic conditions. The findings also note EcN's capacity to form biofilms under a broader range of conditions. The findings emphasize the importance of environmental stability for bacterial survival, revealing that UPEC and EcN form more biofilm in static conditions. The study identifies crucial roles for cellular structures like Type 1 fimbriae and P-pili in UPEC's attachment and invasion processes. It highlights the modulation of surface structures, such as curli and Ag43, that contribute to biofilm stability at elevated temperatures. Additionally, the gene papA demonstrates a higher expression under body temperature and low oxygen conditions. This study aims to deepen our understanding of UPEC's adaptive mechanisms, which may help us develop more effective treatment strategies for urinary tract infections.

Rights

©2024 Asmae Lichir. Access limited to the Smith College community and other researchers while on campus. Smith College community members also may access from off-campus using a Smith College log-in. Other off-campus researchers may request a copy through Interlibrary Loan for personal use.

Language

English

Comments

78 pages: color illustrations. Includes bibliographical references (pages 71-75).

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