Limits of rapid diagnostics: genomic and structural insights into OXA-48–like mediated carbapenem resistance in Escherichia coli

. Resistome and virulome profiles were broadly conserved across meropenem-susceptible and resistant isolates. Structural modeling and protein-ligand interaction analyses of OXA-48, OXA-244, OXA-181, and OXA-484 illustrate how the substitutions Arg214Gly and Thr104Ala are consistent with localized alterations in active site geometry, despite preservation of key ligand interactions. These observations help explain the observed discordance between genotype and phenotype and highlight the limitations of relying solely on rapid gene detection for treatment decisions. Collectively, these findings highlight the need to interpret rapid PCR-based carbapenemase detection in conjunction with phenotypic susceptibility testing and genomic context, supporting balanced antimicrobial decision-making that preserves carbapenem use when appropriate while maintaining vigilance against the silent spread of carbapenemase-producing strains.