Semester of Graduation

Summer of 2024

Degree

Master of Science (MS)

Department

Department of Pathobiological Sciences

Document Type

Thesis

Abstract

Klebsiella pneumoniae (KP), a Gram-negative bacterium, induces severe pneumonia associated with devastating pathological consequences in the lung, such as substantial parenchymal damage. K. pneumoniae is responsible for causing life-threatening lung infections in patients with alcoholics and diabetics. The need to look for new therapeutic approaches is due to the emergence of Klebsiella pneumoniae strains that are resistant to many drugs. The effects of acute alcohol consumption on the host’s innate immune response to KP during infection remain unclear. Age-matched C57BL/6 female mice were administered 6g/kg of 32% alcohol or same amount of PBS via oral gavage 30 minutes prior to infection with KP (ATCC 43816 strain, 1*103 colony forming units (CFU) for acute pneumonia and survival studies in 50uL/mouse) through the intra-tracheal route. After 24 and 48 hours of KP infection, mice were euthanized, and the bacterial burden in each organ was enumerated along with bronchoalveolar lavage fluid (BALF) phenotyping. We treated the bone marrow-derived neutrophils (BMDNs) from mouse with two different dose of alcohol and assessed the extracellular bacterial killing ability and Neutrophil Extracellular Trap (NET) formation at different time points. We also analyzed the levels of different granulocyte population and granulocyte progenitor cells in the blood and bone marrow at 12-hour time point using flow cytometry. Acute alcohol treatment of WT mice after KP infection resulted in decreased host survival, increased bacterial burden in the lungs, BALF, liver, and spleens, as well as increased recruitment of neutrophils and macrophages in the BALF of mice compared with saline treated mice. Treatment with 25mM and 250mM alcohol in BMDNs inhibited the extracellular bacterial killing ability of neutrophil at 6-hour time point. High alcohol concentration such as 250mM significantly attenuates NETosis compared with non-alcohol treatment group in each hour till 8 hrs observation using fluorometry. Interestingly, acute alcohol contributes to modulation of emergency granulopoiesis but not to a significant level. Taken together, our research study indicated that acute alcohol exposure is detrimental to host innate immune response against Klebsiella pneumoniae-induced pneumonia.

Date

7-16-2024

Committee Chair

Jeyaseelan, Samithamby

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Available for download on Wednesday, July 16, 2025

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