Macrolide resistance via 23S rRNA gene mutation in Corynebacterium ulcerans
Corynebacterium ulcerans is a zoonotic pathogen that can cause diphtheria-like illness in humans, including respiratory infections, skin lesions and ulcers. Macrolide resistance in corynebacteria is mainly acquired through horizontal transfer of erm genes encoding rRNA methylases (notably ermX), and of genes coding for efflux pumps (mef). We describe a toxigenic C. ulcerans strain (ST326) from a cat showing macrolide resistance without identifiable resistance genes, but with a mutation in the gene coding for the 23S rRNA.