Mycobacterium intermedium : A rare form of nontubercular Mycobacteria


Nontubercular mycobacteria (NTM) are widely distributed in the environment. Though Mycobacterium avium-intracellulare complex (MAC) is the most common NTM species causing disease in humans, new species of NTM are being isolated due to improved methods of detection and increased physician awareness. One of these rare form of NTM is Mycobacterium intermedium. Although the disease was first reported in 1993, there are only very few cases have been reported so far. Here we are presenting a case of 40-year-old nonsmoker, nondiabetic, non-immunosuppressed person who initially sought medical attention for high grade fever, cough with mucoid expectoration, and breathlessness for 2 weeks and later diagnosed to be a case of M. intermedium.

Keywords: Mycobacterium intermedium, nontubercular mycobacteria (NTM), mycobacterium avium-intracellulare complex (MAC)

How to cite this article:
Kundu S, Ghosh S, Mandi F, Kar S. Mycobacterium intermedium : A rare form of nontubercular Mycobacteria. Ann Trop Med Public Health 2013;6:658-60
How to cite this URL:
Kundu S, Ghosh S, Mandi F, Kar S. Mycobacterium intermedium : A rare form of nontubercular Mycobacteria. Ann Trop Med Public Health [serial online] 2013 [cited 2021 Mar 4];6:658-60. Available from:

Atypical (nontubercular) mycobacteria have been classified by Runyon (Runyon, 1959) as group I-photochromogens, group II-scotochromogens, group III-nonphotochromogens, and group IV-fast growers. Mycobacterium intermedium, a slowly growing photochromogenic mycobacteria was first repeatedly isolated from sputum of a patient with pulmonary disease in 1993. [1] There was another case report of isolation of this organism in a 76-year-old man with a history of pulmonary tuberculosis in 2004. [2]

Case Report

A 40-year-old nonsmoker, nondiabetic, non-immunosuppressed man sought medical attention for high grade fever, cough with mucoid expectoration, and breathlessness for 2 weeks and history of scanty hemoptysis 7 days back. He had history of cough with occasional sputum production and loss of weight and appetite for last 1 year. Patient had past history of pulmonary tuberculosis 2 years back for which he took antitubercular drugs for 6 months.

On general survey patient had poor nutrition and grade 1 clubbing. Examination of respiratory system revealed shifting of trachea towards right, bronchial breath sound and presence of crepitations more in infraclavicular area.

Investigation showed neutrophilic leukocytosis and erythrocyte sedimentation rate (ESR) 60 mm (1 st h). Sputum smear for acid fast bacilli (AFB) was negative on two occasions. Chest radiography showed opacities in right upper and mid zone of lung with shifting of trachea towards right [Figure 1]a. After receiving intravenous antibiotics patient improved both clinically and radiologically and was discharged [Figure 1]b.

Figure 1: (a) Chest X-Ray postero anterior view (CXR-PA) showing a nonhomogenous opacity in right upper and midzone of lung with trachea shifting towards right. (b) CXR-PA showing clearing of the opacity in right lung

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One month later he again got admitted due to persistent distressing cough and increasing breathlessness. This time his total leukocyte count was normal as well as sputum for AFB was negative. As his symptoms were not improving we went for high-resolution computed tomography high resolution computed tomography (HRCT) thorax which revealed bilateral upper lobe fibrocystic and bronchiectatic changes [Figure 2]. Thereafter, fiber optic bronchoscopy (FOB) was done. BAL fluid BACTEC culture revealed Mycobacterium other than tubercle bacilli (MOTT). Genotyping identified the organism as M. intermedium [Figure 3].

Figure 2: Computed tomography (CT) scan showing bilateral bronchiectatic changes predominantly on the right

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Figure 3: Genotyping showing Mycobacterium intermedium

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The GenoType Mycobacterium common mycobacteria/ additional species (CM/AS) assay (Hain Lifescience, GmbH, Nehren, Germany) is based on a multiplex polymerase chain reaction (PCR) targeting species-specific deoxyribo nucleic acid (DNA) regions combined with a reverse hybridization format (DNA strip). The GenoType Mycobacterium CM/AS assay targeting 23S rRNA gene region was performed as recommended by the manufacturer. Briefly, for amplification a primer-nucleotide mixture (provided with the kit), amplification buffer containing MgCl 2 , hot start Taq polymerase (QIAGEN, Hilden, Germany), and heat-inactivated suspension was used. Hybridization and detection were performed in an automated washing and shaking device (Profiblot; Tekan, Maennedorf, Switzerland). For colorimetric detection of hybridized amplicons, streptavidin conjugated with alkaline phosphatase was added. A specific banding pattern develops on the DNA strip which detects species-specific mycobacteria. [3]

After going through extensive searching in standard textbooks and internet, we started oral ethambutol 15 mg/kg body weight, rifampicin 600 mg, clarithromycin 1,000 mg daily, and continued for 1 year. Patient improved symptomatically and gained 4 kg of weight. Sputum was negative for AFB after 2 months as well as after 1 year. Repeat bronchoscopy after 1 year was done. BAL fluid showed no AFB on stain as well as culture this time.


Nontubercular mycobacteria (NTM) occur commonly in the presence of structural lung disease. Our patient had persistent cough with occasional sputum production as well as loss of weight and appetite. Radiographic abnormalties were consistent with postinfective bronchiectatic changes. As patient was not improving, FOB was done as we thought it may be a case of recurrence of pulmonary tuberculosis (Mycobacterium tuberculosis). But to our surprise it came to be a case of M. intermedium. Few cases are reported till date. Clinical, radiographic, and microbiologic criteria for nontuberculous mycobacterial lung disease was met as per American Thoracic Society (ATS) guidelines. [4]

There are no current recommendations for antimicrobial susceptibility testing for less commonly isolated NTM species. In original report this organism was susceptible to ethambutol. [1] Another cases showed its susceptibility to clarithromycin, ethambutol, and rifampicin. [2]

Combination therapy of ethambutol, clarithromycin, and rifampicin resulted in significant clinical improvement in our patient reflecting pathogenic potential of this organism in humans. More research on this M. intermedium in humans is yet to be done.

1. Meier A, Kirschner P, Schro¨der KH, Wolters J, Kroppenstedt RM, Bo¨ttger EC. Mycobacterium intermedium sp. nov. Int J Syst Bacteriol 1993;43:204-9.
2. Ito A, Kishi F, Saito N, Kazumi Y, Mitarai S. Pulmonary Mycobacterium intermedium disease in an elderly man with healed pulmonary tuberculosis. J Clin Microbiol 2005;43:1473-4.
3. Richter E, Ru¨sch-Gerdes S, Hillemann D. Evaluation of the GenoType Mycobacterium assay for identification of mycobacterial species from cultures. J Clin Microbiol 2006;44:1769-75.
4. American Thoracic Society. Diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Am J Respir Crit Care Med 2007;175:367-416.

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1755-6783.140246


[Figure 1], [Figure 2], [Figure 3]

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