Characterization of secreted pathogenicity factors from Acinetobacter baumannii

GIACONE, L; REPIZO G; MORAN BARRIO J

Congreso; AcinetoVibes 2021; 2021

Acinetobacter baumannii (Ab) is a nosocomial pathogen, of major concern due to its multi-drug resistance (MDR) and the recent appearance of hyper-virulent strains in the clinical settings. The World Health Organization classified Ab as a critical pathogen for which new antibiotics are urgently required. Ab pathogenesis is associated with a multitude of potential virulence factors (VF) that remain poorly characterized.In the present work we studied the physiopathology of the MDR Ab strain AB5075. We conducted a bioinformatic prediction using available datasets to construct a list of putative lipoproteins that might be acting as secreted VF. Seven candidates were selected and the corresponding mutants were obtained from the Manoil Lab collection (1).Physiological and microbiological analyses of the mutants were performed. Four of them showed higher levels of biofilm formation, lower eukaryotic A549 cells adherence and invasion (2), and different patterns of macrocolonies in congo red agar, as compared to wt. Additional in silico analysis revealed that one of the resulting proteins share high similarity with other bacterial proteins involved in biofilm formation. The rest of the genes are in proximity to others related to stress response or other virulence processes like capsule formation, thus suggesting probable regulatory functions. Further analysis will contribute to the understanding of Ab virulence mechanisms, revealing novel possible targets for therapeutic development.1. Gallagher LA. et al. J bacteriol 197.12 (2015): 2027-2035.2. Giacone L. et al. ISEV 2020 Annual Meeting.