Masters Thesis

Characterization of Virulence Factors in A47: A Novel Species of Acinetobacter

Of the Acinetobacter genus A. baumannii is the most common cause of hospital-acquired infections, but recently additional species of Acinetobacter have been identified as origins of nosocomial infections. Studies suggest functional type IV pili (T4P) have important roles in virulence factors such as biofilm formation, and horizontal genetic transfer (HGT). Other virulence factors such as hemolytic activity and antimicrobial resistance are important mechanisms of pathogenesis. a novel species of Acinetobacter (A47) was isolated from a patient and determined to be a hospital acquired infection. the research here focuses on identifying potential virulence factors harbored by A47 through both genomic and phenotypic methods. a novel chromosomally located OXA-like β-lactamase gene was identified and analysis of the genetic context indicated it is not linked to a mobile element. A47 harbored genes required for T4P biogenesis and assays assessing biofilm formation and natural transformation were carried out. A47 formed low levels of biofilm on polystyrene plastic and borosilicate glass. A47 can naturally acquire both genomic DNA (gDNA), and plasmid DNA. Moreover, surface structures observed with scanning electron microscopy (SEM) exposed long cellular appendages and shorter pili-like structures. Hemolytic activity was quantified over time and indicated A47 is β-hemolytic. Taken together these results provide insight into the pathobiology of a novel species of Acinetobacter.

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