RT Journal Article
T1 Pathogenic Acinetobacter species have a functional type I secretion system and contact-dependent inhibition systems.
A1 Harding, Christian M
A1 Pulido, Marina R
A1 Di Venanzio, Gisela
A1 Kinsella, Rachel L
A1 Webb, Andrew I
A1 Scott, Nichollas E
A1 Pachón, Jerónimo
A1 Feldman, Mario F
K1 Acinetobacter
K1 bacterial pathogenesis
K1 bacterial toxin
K1 biofilm
K1 contact-dependent inhibition system
K1 protein secretion
K1 proteomics
K1 type I secretion system
AB Pathogenic Acinetobacter species, including Acinetobacter baumannii and Acinetobacter nosocomialis, are opportunistic human pathogens of increasing relevance worldwide. Although their mechanisms of drug resistance are well studied, the virulence factors that govern Acinetobacter pathogenesis are incompletely characterized. Here we define the complete secretome of A. nosocomialis strain M2 in minimal medium and demonstrate that pathogenic Acinetobacter species produce both a functional type I secretion system (T1SS) and a contact-dependent inhibition (CDI) system. Using bioinformatics, quantitative proteomics, and mutational analyses, we show that Acinetobacter uses its T1SS for exporting two putative T1SS effectors, an Repeats-in-Toxin (RTX)-serralysin-like toxin, and the biofilm-associated protein (Bap). Moreover, we found that mutation of any component of the T1SS system abrogated type VI secretion activity under nutrient-limited conditions, indicating a previously unrecognized cross-talk between these two systems. We also demonstrate that the Acinetobacter T1SS is required for biofilm formation. Last, we show that both A. nosocomialis and A. baumannii produce functioning CDI systems that mediate growth inhibition of sister cells lacking the cognate immunity protein. The Acinetobacter CDI systems are widely distributed across pathogenic Acinetobacter species, with many A. baumannii isolates harboring two distinct CDI systems. Collectively, these data demonstrate the power of differential, quantitative proteomics approaches to study secreted proteins, define the role of previously uncharacterized protein export systems, and observe cross-talk between secretion systems in the pathobiology of medically relevant Acinetobacter species.
YR 2017
FD 2017-04-03
LK http://hdl.handle.net/10668/11048
UL http://hdl.handle.net/10668/11048
LA en
DS RISalud
RD Apr 18, 2025