Towards the complete proteinaceous regulome of Acinetobacter baumannii

Abstract

The emergence ofAcinetobacter baumanniistrains, with broad multidrug-resistance phenotypes and novel virulence factorsunique to hypervirulent strains, presents a major threat to human health worldwide. Although a number of studies havedescribed virulence-affecting entities for this organism, very few have identified regulatory elements controlling theirexpression. Previously, our group has documented the global identification and curation of regulatory RNAs inA. baumannii.As such, in the present study, we detail an extension of this work, the performance of an extensive bioinformatic analysis toidentify regulatory proteins in the recently annotated genome of the highly virulent AB5075 strain. In so doing, 243transcription factors, 14 two-component systems (TCSs), 2 orphan response regulators, 1 hybrid TCS and 5sfactors werefound. A comparison of these elements between AB5075 and other clinical isolates, as well as a laboratory strain, led to theidentification of several conserved regulatory elements, whilst at the same time uncovering regulators unique tohypervirulent strains. Lastly, by comparing regulatory elements compiled in this study to genes shown to be essential forAB5075 infection, we were able to highlight elements with a specific importance for pathogenic behaviour. Collectively, ourwork offers a unique insight into the regulatory network ofA. baumanniistrains, and provides insight into the evolution ofhypervirulent lineages