A global post-transcriptional regulator directs Acinetobacter baumannii carbon preference and gut colonization
Year: 2026
Type: preprint
Abstract: Acinetobacter baumannii is a multidrug-resistant pathogen that colonizes the gut, increasing the risk of subsequent infection and transmission. Recent work showed that A. baumannii catabolizes ornithine, a non-preferred carbon source, to colonize the gut. However, the mechanisms of carbon preference were unknown in A. baumannii . Here, experimental evolution identified the conserved RNA-binding protein CsrA as a regulator of carbon preference in A. baumannii , a previously unreported CsrA function. RNA immunoprecipitation sequencing (RIP-Seq) revealed hundreds of CsrA-associated transcripts. A. baumannii CsrA directly bound and repressed expression of the ast arginine/ornithine catabolic operons. The Pseudomonas aeruginosa CsrA homolog RsmA repressed arginine/ornithine catabolic operon expression, suggesting this CsrA function extends to other bacterial taxa. Finally, CsrA was required for competitive fitness during A. baumannii gut colonization. These findings uncover a previously unrecognized role for a global regulator in A. baumannii carbon preference and persistence in the gut, a critical reservoir for multidrug-resistant pathogens.
Institutions: University of Illinois Chicago, University of Iowa
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7225734861
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