Background

Mycobacterium cosmeticum is an emerging rapidly growing mycobacteria (RGM) species that has been rarely reported to cause human disease. RGM catheter-related bloodstream infections (CRBSI) are often challenging to treat given the need for line removal, variable species-dependent antimicrobial susceptibility, combination antimicrobial treatment, and historically longer courses of antibiotics.

Case presentation

We present a case of an immunocompetent pediatric patient with severe hemophilia B and M. cosmeticum CRBSI. While the patient's hemophilia B precluded a standard line holiday, he successfully cleared his infection with two line exchanges followed by two weeks of antibiotics.

Conclusions

RGM, including emerging species M. cosmeticum, may be considered in patients with an indolent presentation of CRBSI. Our case suggests source control with shorter courses of antimicrobials can be successful.