Phenotypic and multiplex PCR-defined antimicrobial resistance in Ukrainian soldiers’ war-wound microbiota

Abstract This study investigates antimicrobial resistance in combat-related wound infections from the ongoing armed conflict in Ukraine using combined phenotypic and molecular approaches. Gram-negative pathogens, predominantly ESKAPE organisms, exhibited high resistance rates, including 43% resistance to imipenem and frequent multidrug resistance in Acinetobacter baumannii , Klebsiella pneumoniae , and Pseudomonas aeruginosa . Molecular analysis revealed β-lactamase and carbapenemase genes in 22/37 isolates, with frequent co-carriage of multiple determinants such as blaCTX-M , blaSHV , blaTEM , blaKPC , blaNDM , and blaOXA-48 . While blaCTX-M strongly correlated with cephalosporin resistance, weaker genotype–phenotype concordance was observed for blaTEM and blaSHV , indicating the contribution of additional resistance mechanisms. Discrepancies between multiplex PCR and phenotypic susceptibility were particularly evident in P. aeruginosa . Additional WGS analyses of selected isolates provided a broader characterization of the resistome and identified resistance determinants not covered by the targeted PCR panel, helping to clarify several genotype–phenotype discrepancies. Less susceptible subpopulations observed for Gram-negative isolates and vanC-mediated intrinsic resistance in Enterococcus gallinarum further emphasized diagnostic complexity. Overall, the findings indicate a high burden and substantial diversity of antimicrobial resistance among the analyzed combat-related wound isolates. These results support the use of integrated diagnostic strategies combining rapid molecular detection with MIC-based phenotypic testing, with broader genomic analyses applied where clinically or epidemiologically justified, to support targeted therapy and antimicrobial stewardship.