Virulence potential of the first Corynebacterium mycetoides strain isolated from human urine: a rare species of Corynebacterium

For many years, the potential pathogenic of non-diphtheriae corynebacteria were underestimated. Nowadays, a growing number of Corynebacterium species are recognized as opportunistic agents of human infections, mainly in hospital settings. In addition, multidrug-resistant Corynebacterium isolates from clinical specimens, have been reported and the role of Corynebacterium spp. in urinary tract infections (UTIs) has been highlighted. Several studies have reported Corynebacterium species as the agent of UTIs especially in patients with risk factors. Thus, the present work aimed to report the first isolation of Corynebacterium mycetoides from human urine and an initial study on its virulence properties. The isolate, initially characterized by phenotypical tests as a multidrug-resistant Corynebacterium sp., was recovered from the urine of a female transplant patient. Mass spectrometry and 16S rRNA and rpoB genes sequencing identified the isolate as C. mycetoides. The isolate was found able to adhere to and survive into epithelial cells (Vero cells), and its pathogenic potential was confirmed when tested against Caenorhabditis elegans nematode. The results obtained suggest that C. mycetoides is a potential pathogen for the urinary tract in humans and for a better understanding of the multifactorial mechanisms of virulence, studies about this species should be continued. (C) 2022 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Automated summary

The potential pathogenicity of non-diphtheriae corynebacteria has been underestimated for a long time. However, an increasing number of Corynebacterium species are now recognized as opportunistic human pathogens, particularly in hospital settings. This study focuses on the first isolation of Corynebacterium mycetoides from human urine and provides initial insights into its virulence properties. The findings suggest that C. mycetoides may be a potential pathogen for urinary tract infections in humans.