Logan Christian

Document Type

Honors Thesis

Major

Biochemistry

Advisor(s)

Melody N. Neely

Committee Members

Mark Brewer, Benjamin King, Melisssa Maginnis, Sally Molloy

Graduation Year

May 2023

Publication Date

2025

Abstract

Diabetes mellitus has become a growing epidemic in the United States as 37.3 million people have been diagnosed with diabetes as of January 2022 (1). Of pregnant mothers, 2– 10% develop gestational diabetes due to hormonal changes that lead to insulin resistance (2). Streptococcus agalactiae (Group B Streptococcus or GBS), a Gram-positive bacterium, and Candida albicans (CA), a polymorphic fungus, are found in a commensal relationship in the vaginal tract. Diabetes ha an increased association with risk of invasive GBS infection in non-pregnant populations and hyperglycemic environments provide C. albicans with excess of its main energy source, glucose (3, 4). We hypothesize that C. albicans protects GBS growth in the presence of environmental stressors such as excess glucose or antibiotics. Analyses were conducted in vitro (co-cultured glucose/antibiotic assays, growth curves, and fluorescent microscopy) and in vivo (Danio rerio, “zebrafish”, survival assays and utilization of a hyperglycemic zebrafish model). Preliminary data, conducted by Patenaude, suggests that GBS growth recovered with C. albicans in a glucose-rich environment. The Neely Lab showed that co-cultured C. albicans and GBS produce increased growth of GBS in excess glucose and a reduction in antibiotic efficacy. Systemic infection indicates that the rate of zebrafish survival decreased in solo infections between GBS and GBS + excess glucose. The presence of GBS and C. albicans grown in excess glucose showed a decreased rate of zebrafish survival compared to a co-infection of GBS and C. albicans without excess glucose. Increased GBS growth and decreased rates of zebrafish survival may be attributed to interactions between these two organisms from a dual infection in the presence of excess glucose.

Download

Share