Infection due to a novel mycobacterium, mimicking multidrug-resistant Mycobacterium tuberculosis

• Published in: Clinical microbiology and infection Vol. 16; no. 8; pp. 1130 - 1134
• Main Authors: Tortoli, E., Rogasi, P.G., Fantoni, E., Beltrami, C., De Francisci, A., Mariottini, A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01-08-2010; Blackwell Publishing Ltd; Wiley-Blackwell; Elsevier Limited
• Subjects: Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; Bacterial diseases; Biological and medical sciences; Case report; Chromatography, High Pressure Liquid; Cluster Analysis; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Drug resistance; Drugs; Human bacterial diseases; Humans; Infection; Infections; Infectious diseases; line probe assay; Lung diseases; Male; Medical research; Medical sciences; Microbial Sensitivity Tests; Microscopy; Middle Aged; Mimicry; Molecular Sequence Data; multidrug-resistant tuberculosis; Mycobacterium Infections, Nontuberculous - diagnosis; Mycobacterium Infections, Nontuberculous - drug therapy; Mycobacterium Infections, Nontuberculous - microbiology; Mycobacterium simulans; Mycobacterium simulans, non-tuberculous mycobacteria; Mycobacterium tuberculosis; Mycolic Acids - analysis; Nontuberculous Mycobacteria - classification; Nontuberculous Mycobacteria - drug effects; Nontuberculous Mycobacteria - genetics; Nontuberculous Mycobacteria - isolation & purification; non‐tuberculous mycobacteria; Phylogeny; Radiography, Thoracic; Sequence Analysis, DNA; Side effects; Somalia; Sputum; Tomography, X-Ray Computed; Tuberculosis; Tuberculosis and atypical mycobacterial infections; Tuberculosis, Multidrug-Resistant - diagnosis; Tuberculosis, Multidrug-Resistant - drug therapy; Tuberculosis, Multidrug-Resistant - microbiology; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - drug therapy; Tuberculosis, Pulmonary - microbiology; Somalia; Case report; multidrug-resistant tuberculosis; Mycobacterium simulans, non-tuberculous mycobacteria; line probe assay; Human; Mycobacterium simulans; Mycobacterial infection; Infection; Case study; Tuberculosis; Mycobacterium tuberculosis; Mycobacteriales; Multiple resistance; Bacteriosis; Mycobacteriaceae; Bacteria; non-tuberculous mycobacteria; Actinomycetes
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1111/j.1469-0691.2009.03063.x

The treatment of multidrug-resistant tuberculosis (TB) requires the use, for long periods, of drugs liable to cause significant side effects. In the case of misdiagnosis of multidrug-resistant TB, the patient is exposed to toxic substances without any benefit. In low-income countries, where the microbiological diagnosis of TB relies on microscopy only, the misdiagnosis of multidrug-resistant TB is very frequent in patients persistently smear-positive despite anti-TB treatment, with the possibility of an infection due to non-tuberculous mycobacteria (NTM) being neglected. The isolation of a mycobacterium from the sputum of a Somali patient apparently confirmed the previous diagnosis of cavitary pulmonary disease. Preliminary investigations led, at first, to the strain being identified as multidrug-resistant Mycobacterium tuberculosis, with findings fully in agreement with the patient's history, which was characterized by repeated interruptions of anti-TB treatment. Thorough phenotypic and genotypic analyses led subsequently to the recognition that the strain was a previously unreported non-tuberculous mycobacterium. The patient, who was unresponsive to the anti-TB treatment, dramatically improved once a drug combination active against NTM was used. A major objective of this article is to alert the medical community to the risk, present also in settings in which sophisticated diagnostic techniques are used, that a cavitary infection due to NTM, and consequently not responding to the anti-TB standard regimen, will be mistaken for multidrug-resistant TB.