Global Distribution and Co-occurrence of Antimicrobial, Biocide, and Metal Resistance Genes in 11,921 Acinetobacter baumannii Genomes.

Authors

Chenmiao Wu, Xiaomeng Yang, Wuzhen Yu

Published in

Current microbiology. Volume 83. Issue 12. Oct 18, 2026. Epub Oct 18, 2026.

Abstract

Acinetobacter baumannii is a critical priority pathogen globally. While antimicrobial resistance genes (ARGs) are well characterized, the prevalence, distribution, and co-occurrence patterns of biocide and metal resistance genes (BMRGs) remain poorly defined at global scale. We performed genomic analysis of 11,921 non-redundant A. baumannii genomes retrieved from NCBI RefSeq, representing isolates from 93 countries collected between 1982 and 2025. ARGs and BMRGs were identified using AMRFinderPlus (v4.2.7; organism-specific mode). Multilocus sequence typing (Pasteur MLST) was performed, and BMRG-ARG co-occurrence was assessed using one-sided Fisher's exact tests for enrichment with Benjamini-Hochberg correction (q < 0.05). Every genome carried at least one AMR determinant, and 99.98% carried at least one biocide or metal resistance locus at initial annotation. AMRFinderPlus identified 687 resistance-associated loci (633 AMR determinants; 39 biocide and metal resistance loci, of which 38 BMRGs were retained for analysis after exclusion of the core-genome gene nreB; and 15 virulence-associated loci, which were excluded from resistance analyses). Sequence type 2 (ST2) accounted for 56.4% of genomes. The carbapenemase gene blaOXA-23 was detected in 62.6% of genomes, and fluoroquinolone resistance mutations were highly prevalent (gyrA S81L: 84.9%; parC S84L: 77.2%). Co-occurrence analysis identified 38 significant BMRG-ARG associations overall (q < 0.05, OR ≥ 10), with a prominent module linking the integron-associated marker qacEΔ1 to ARGs (e.g., sul1, aadA1); the population-level mercury resistance-tet(A) association was not supported in the phylogeny-based sensitivity analysis. This study provides quantitative evidence for structured BMRG-ARG co-occurrence patterns in A. baumannii, shaped by ST2 dominance. These patterns are consistent with possible linkage and co-selection, although the present data cannot establish physical linkage.

PMID:
42893470
Bibliographic data and abstract were imported from PubMed on 19 Oct 2026.

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