Emerging Pathogenicity

Along with other previously considered non-pathogenic Corynebacterium species, an example of a non-toxigenic strain of Corynebacterium diphtheriae has been reported by Gomes et al., in Brazil as the cause of an invasive infection from a nephrostomy catheter placement in an elderly person with bladder cancer.¹⁰

This non-toxigenic strain was shown to readily produce a biofilm on plastic. As the numbers of immunocompromised patients increase, an increased likelihood of these types of infections warrants a push for full identification of Corynebacterium species.

While it can be difficult to determine infections caused by organisms that can also be part of the normal flora, isolates should be considered a potential pathogen when recovered in pure culture with heavy growth and a direct specimen Gram stain demonstrating gram-positive bacilli surrounded or ingested by polymorphonuclear (PMNs) cells.