Item Details

title

ROLE OF ETHANOLAMINE UTILIZATION ON THE GROWTH OF KLEBSIELLA PNEUMONIAE

author

Barnes, Andrew Jordan

abstract

Klebsiella pneumoniae is a leading cause of nosocomial infections and transmits through the fecal-oral route, leading to asymptomatic gastrointestinal (GI) colonization prior to translocation to sterile sites within the host. A molecular understanding of how K. pneumoniae colonizes the GI tract is missing. K. pneumoniae uses metabolic pathways to bypass nutrient competition to overcome colonization resistance (CR) from the host microbiota and establish itself in the gut. Identifying the utilization and regulation of these alternative nutrient sources would allow for a better understanding of K. pneumoniae colonization, host-to-host transmission and potentially identify targets for intervention. Ethanolamine, derived from phosphatidylethanolamine within cell membranes, can be metabolized by K. pneumoniae to provide a nitrogen and a carbon source through the ethanolamine utilization (eut) genes. Klebsiella is unique in that it possesses two genetically distinct loci for ethanolamine metabolism: a long locus and a short locus. Aerobic and anaerobic studies revealed unique roles for each eut locus depending on EA utilization as either a carbon or nitrogen source. Through our novel K. pneumoniae murine gut colonization model, we demonstrated in competitive experiments a long locus mutant outcompeted the short locus mutant in the GI-tract, suggesting the importance of the short locus in colonization through metabolism of ethanolamine likely as a nitrogen source. Using quantitative real time polymerase chain reaction (qRT-PCR) we demonstrated that EutR is required for the upregulation of the long but not the short locus and NtrC upregulates the short locus when ethanolamine is provided as the sole nitrogen source. Through biofilm and survival assays, we determined EA may promote fomite survival and enhance transmission. Together, these data enrich our understanding of the role ethanolamine plays in K. pneumoniae gut colonization.

subject

Colonization Resistance

Ethanolamine

GI Colonization

Klebsiella pneumoniae

NtrC

RpoN

contributor

Zafar, Muhammad A (advisor)

Haas, Karen M (committee member)

Walker, Kimberly A (committee member)

date

2023-07-25T17:48:44Z (accessioned)

2023 (issued)

degree

Biomedical Science – MS (discipline)

embargo

2024-06-06 (terms)

2024-06-06 (liftdate)

identifier

http://hdl.handle.net/10339/102272 (uri)

language

en (iso)

publisher

Wake Forest University

type

Thesis