Comparative genomic and phenotypic analysis of Corynebacterium macginleyi from ocular infections

Corynebacterium macginleyi is an opportunistic pathogen linked to ocular infections, but comprehensive genomic studies remain scarce, especially in China. This study characterized its genomic features, virulence potential, and antimicrobial resistance using 13 clinical isolates and 27 public genomes. Methods included matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), average nucleotide identity (ANI), whole-genome sequencing, Clusters of Orthologous Groups/Kyoto Encyclopedia of Genes and Genomes annotation, core-single nucleotide polymorphism phylogeny, virulence and resistance gene analysis, and Clinical and Laboratory Standards Institute susceptibility testing. All isolates were accurately identified as C. macginleyi, with MALDI-TOF MS and ANI outperforming conventional methods. Phylogenetic analysis revealed three clades with geographic clustering. Functional profiles were centered on metabolism. Virulence genes were conserved, mainly mediating adhesion, stress response, and immune evasion. Resistance genes were limited but diverse, dominated by erm(X). Phenotypic testing showed frequent macrolide resistance, while most isolates remained susceptible to the other tested antimicrobials; fluoroquinolone resistance was detected in a subset of isolates. Isolate B64 exhibited a unique phylogenetic position, higher virulence, and resistance gene burden, consistent with multidrug resistance. In conclusion, C. macginleyi shows geographic diversity, conserved virulence, and evolving resistance, supporting precise identification and continuous surveillance.IMPORTANCEThe precise molecular mechanisms underlying the pathogenicity of Corynebacterium macginleyi are not fully elucidated, and large-scale genomic and epidemiological studies are still limited, particularly in certain regions such as China. Therefore, comprehensive investigations integrating whole-genome sequencing with clinical data are urgently needed to better understand its genetic characteristics, virulence-associated traits, and antimicrobial resistance profiles. Such efforts will provide a critical foundation for improving diagnostic accuracy and optimizing therapeutic strategies for ocular infections caused by this organism.