Multifocal subcutaneous infection by Corynebacterium glucuronolyticum: expanded pathogenicity and multidrug resistance

Corynebacterium glucuronolyticum is a Gram-positive bacterium primarily associated with chronic genitourinary tract infections. However, subcutaneous infections caused by this organism have rarely been documented. We describe the first case of multifocal subcutaneous masses caused by C. glucuronolyticum in an immunocompetent male. Cultures from both lesions yielded C. glucuronolyticum , identified by matrix-assisted laser desorption/ionisation–time of flight (MALDI-TOF) mass spectrometry and 16S rRNA sequencing. Whole-genome sequencing confirmed species identity. Nine antimicrobial resistance genes, sul1, aadA13, cmx, aph(6)-Id, aph(3'’)-Ib, aph(3')-Ia, aac(3)-XI, erm(X), tet(W) and one biocide resistance gene ( qacEΔ1 ) were identified. Phenotypic susceptibility results were concordant with genomic findings. Except for intrinsic tet(W) , all were associated with mobile elements forming the multidrug resistance region. Comparative analyses suggested interspecies horizontal gene transfer. Multiple virulence factors were also detected. This case expands the pathogenic potential of C. glucuronolyticum beyond the genitourinary tract and highlights the importance for accurate identification and genomic analysis of this emerging pathogen.