Mycobacterium riyadhense lung infection in a patient with HIV/AIDS

Abstract

Mycobacterium riyadhense was first isolated in 2009. Five additional cases were reported since then. This is, however, the first case of M. riyadhense with human immunodeficiency virus coinfection in the literature. A 54-year-old male diabetic presented with 4 months history of diarrhea, productive cough, odynophagia, and dysphagia with progressive weight loss. He looked cachectic with oropharyngeal thrush, bilateral axillary lymph node enlargement and herpes zoster involving the first two thoracic dermatomes. He had right-sided consolidation on chest examination. He was anemic with a normal platelet count. Sputum examination was positive for acid-fast bacilli (AFB); however, deoxyribonucleic acid probe-detection assay for MTB (complex) was negative. The isolate was confirmed as M. riyadhense at the Bioscientia laboratories (Ingelheim, Germany). Stool was positive for Clostridium difficile toxins by polymerase chain reaction (PCR). Human immunodeficiency virus (HIV) test was also positive. The patient showed improvement in clinical, bacteriologic, and immunologic parameters with antituberculous and antiretroviral medications. The lesson from this case is for clinicians to suspect infection with atypical mycobacteria once mycobacterium tuberculosis (MTB) PCR is negative in a patient with a positive smear for AFB so that appropriate therapy for nontuberculous mycobacterial disease can be initiated early.