Honors Program

University Honors

Date of Award


Thesis Professor(s)

Erik Petersen

Thesis Professor Department

Health Sciences

Thesis Reader(s)

Sean Fox


Acinetobacter baumannii is a prevalent nosocomial pathogen where, like many other infectious bacteria, A. baumannii is increasingly considered a multi-drug resistant pathogen. This research study was designed to find a way to affect the persistence of A. baumannii such that it can be applied to a hospital setting to prevent further nosocomial infections. One regulatory mechanism potentially used by A. baumannii to persist on hospital surfaces is through the use of the bacterial second messenger cyclic-di-GMP (c-di-GMP). This nucleotide signal is regulated in response to environmental conditions, and then activates c-di-GMP-binding proteins that induce phenotypic changes. One c-di-GMP-regulated phenotype is bacterial motility, and reducing motility may alter A. baumannii’s ability to colonize and persist on hospital surfaces. I hypothesized that A. baumannii uses c-di-GMP-binding proteins to regulate motility. A. baumannii encodes two potential c-di-GMP-binding proteins of interest, one that contains a sole c-di-GMP-binding PilZ domain and another that pairs a PilZ domain with a hydrolase enzymatic domain. I am also testing two A. baumannii strains: AB5075, a recent multi-drug resistant military hospital isolate and 17978, an established lab strain. A notable difference between these two strains is that AB5075 demonstrates twitching motility where it utilizes type IV pili, while 17978 demonstrates swarming motility that has unknown mechanisms. Both c-di-GMP-binding proteins were tested for their role in motility for the particular A. baumannii strain. While I am still generating the deletion strain for the c-di-GMP-binding hydrolase enzyme in AB5075, the sole PilZ domain protein is required for twitching motility, while both c-di-GMP-binding proteins are required for 17978 swarming motility. [PM1] Future plans include determining the role of the c-di-GMP-binding hydrolase enzyme in twitching motility and identifying the role that these proteins play through binding of c-di-GMP.


East Tennessee State University

Document Type

Honors Thesis - Withheld

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