RND pumps across the genus Acinetobacter: AdeIJK is the universal efflux pump

Area of Science:

• Microbiology
• Molecular Biology
• Genomics

Background:

• Acinetobacter species, including the multidrug-resistant A. baumannii, cause significant human infections.
• While A. baumannii has multiple resistance nodulation division (RND) efflux pumps, their distribution across the Acinetobacter genus is unknown.
• RND efflux pumps are crucial for antibiotic export and resistance in bacteria.

Purpose of the Study:

• To investigate the distribution and types of RND efflux pumps across the Acinetobacter genus.
• To identify conserved RND systems essential for Acinetobacter survival.
• To understand the role of specific RND pumps in Acinetobacter-associated infections.

Main Methods:

• Genomic analysis of 64 Acinetobacter species to identify RND systems.
• Development of a novel method to predict RND protein numbers using conserved residues.
• Genomic, structural, and phenotypic analyses to confirm RND system homology.

Main Results:

• The AdeIJK/AdeXYZ system is conserved across all studied Acinetobacter species, suggesting it's a fundamental RND system.
• A novel method accurately predicted RND protein numbers, revealing variations within and across species.
• Infected-associated species tend to encode more RND pumps, with systems like AdeABC and AdeFGH found in a subset.

Conclusions:

• AdeIJK is the core RND efflux system in Acinetobacter, vital for survival, homeostasis, and likely antibiotic resistance.
• Additional RND systems are associated with infection and may represent targets for therapeutic intervention.
• Understanding RND pump mechanisms can guide the development of treatments to overcome efflux-mediated resistance in Acinetobacter infections.