A Case of False-PositiveMycobacterium tuberculosisCaused byMycobacterium celatum

Abstract

Mycobacterium celatumis a nontuberculous mycobacterium shown to cause symptoms similar to pulmonaryM. tuberculosis. Certain strains have been shown to cross-react with the probes used to detectM. tuberculosis, making this a diagnostic challenge. We present a 56-year-old gentleman who developed signs and symptoms of lung infection with computed tomography scan of the chest showing right lung apex cavitation. Serial sputum samples were positive for acid-fast bacilli and nucleic acid amplification testing identifiedM. tuberculosisribosomal RNA, resulting in treatment initiation. Further testing with high performance liquid chromatography showed a pattern consistent withM. celatum. This case illustrates the potential forM. celatumto mimicM. tuberculosisin both its clinical history and laboratory testing due to the identical oligonucleotide sequence contained in both. An increasing number of case reports suggest that early reliable differentiation could reduce unnecessary treatment and public health intervention associated with misdiagnosed tuberculosis.