Infrapatellar bursitis with Mycobacterium malmoense related to immune reconstitution inflammatory syndrome in an HIV-positive patient.

The immune reconstitution inflammatory syndrome (IRIS) after starting antiretroviral treatment for HIV infection can be caused by a great variety of pathogens. Among these are non-tuberculous mycobacteria (NTM), with Mycobacterium avium complex being the most commonly described finding. Antimycobacterial treatment of NTM in cases of IRIS is controversial. We report the case of a 39-year-old man diagnosed with HIV-1 infection during admission to hospital with Pneumocystis jirovecii pneumonia (PCP) and a CD4 cell count of 60/μl. The patient started antiretroviral treatment and made an uneventful recovery from the PCP diagnosis, but was readmitted after 2.5 months with a purulent infrapatellar bursitis on the left knee. A surgical procedure was performed and Mycobacterium malmoense was grown from the pus from the bursa. The patient recovered without supplemental antimycobacterial treatment. To our knowledge, this is the first report on IRIS caused by M malmoense.