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Nontuberculous mycobacteria: Trick or treat--A case of Mycobacterium lentiflavum.


Mycobacterium lentiflavum is a recently described slow-growing nontuberculous mycobacterial species. It was first identified as a distinct strain in 1996 by Springer et al. [1] M. lentiflavum is a Gram-positive bacterium, slowly growing yellow tiny colonies at 22 [degrees]C-37 [degrees]C in 3-4 weeks. Because of similarity to Mycobacterium simiae on mycolic acid and fatty acid chromatography patterns and to Mycobacterium avium complex (MAC) on biochemical characteristics, genetic analysis is essential for proper identification. [1]

Several cases of M. lentiflavum infections have been seen in immunocompromised hosts, but some in immunocompetent, as well. Neck lymphadenitis in children is the most frequent pathology due to this organism in literature, but there are disseminated infections, pleural effusions, and ascites as well. [2-4]

Talking about nontuberculous mycobacteria (NTM), it is hard to say if it is an infectious agent or not. These bacteria have been known since the 1950s. [5] There is still ongoing discussion about their infectious potentials and necessity of treatment. We present a case with M. lentiflavum who needed treatment.

Case Report

A 59-year-old female patient was admitted to the pulmonary clinic with fatigue, cough, and hemoptysis for 2 months. In her medical history, she underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy operation for benign causes. She has been diagnosed with multiple sclerosis (MS) in remission, and to conserve her muscle strength, she went to a public swimming pool three times a week. On auscultation, medium crackles were found on the left lung. Bilateral increased opacities were shown on chest X-ray. Respiratory function test was normal. On thoracic computed tomography (CT), there were bilateral cavitating centriacinar nodules, bronchiectasis, and tree-in-bud pattern [Figure 1]. As she could not provide sputum, fiber-optic bronchoscopy was performed [Figure 2]. Bronchoalveolar lavage fluid (BALF) sampling, bronchial brushing, and transbronchial biopsy were performed. Cytological and pathological examination of the specimens showed inflammation but no malignancy. BALF specimen was tested for acid-fast bacilli (AFB) and cultured after being processed by NaOH-NALC in National Tuberculosis Reference Laboratory. Ehrlich Ziehl-Neelsen method was used for AFB microscopy, which was positive. The specimen was cultured on both Lowenstein-Jensen solid medium and BACTEC MGIT 960 (Becton Dickinson, Sparks, Maryland, USA) liquid culture system. The strain growing in BACTEC MGIT 960 system was differentiated in terms of Mycobacterium tuberculosis complex and NTM by BD MGIT TBc Identification immunochromatographic assay (Becton Dickinson, Sparks, Maryland, USA), which was negative, suggesting that the strain could be NTM. M. lentiflavum was identified by GenoType Mycobacterium CM/AS kit (Ver 1.0) (HAIN Lifescience). Drug susceptibility of M. lentiflavum was studied by SLOMYCO-SENSITITRE[R] Broth Microdilution (Trek Diagnostic Systems Limited, UK) used for slowly growing mycobacteria. M. lentiflavum strain was susceptible to amikacin, clarithromycin, moxifloxacin, and rifabutin, while it was resistant to ciprofloxacin, ethambutol, linezolid, and rifampin.

As the patient was symptomatic for cough and hemoptysis, along with positive findings on CT, antimicrobial therapy (ethambutol 1000 mg/day, clarithromycin 1000 mg/day, and rifabutin 300 mg/day) was initiated and lasted for 1 year. Her symptoms were alleviated by therapy without any side effects. She has been free of symptoms for 2 years.


Disease caused by NTM is common in immunocompromised patients, the most common of which is MAC in the USA. [5] Ford et al. showed that while 52.1% isolated NTM are MAC in Washington, only 1.8% are M. lentiflavum. [6] M. lentiflavum infections are seen in especially industrialized countries. [5] Cases of human diseases have been reported, including several pulmonary diseases, cervical lymphadenitis, liver abscess, and disseminated infection. [7] Disseminated infections were seen in immunocompromised patients, frequently in HIV-positive cases. [8] The present patient who had been diagnosed with MS did not use any kind of medication for this disease, which could cause immunosuppression. She did not have any evidence of immunosuppression; however, she developed a symptomatic NTM infection by M. lentiflavum. To understand the nature of the M. lentiflavum infection in immunocompetent patients, Yagi et al. reviewed data of 16 patients. [9] Of 16 patients, 11 were female and 15 had bronchiectatic/nodular pattern on CT like our case. In literature, some immunocompetent patients with structural lung diseases such as bronchiectasis (both cystic fibrosis (CF) and non-CF) or risk factors such as smoking and mine working have been reported. [3,10] However, our patient had none of these risk factors.

As NTM are frequently found in soil and water, there are high isolation rates for NTM worldwide. [11] Humans are probably infected by environmental bacteria. Swimming pools may be a source for NTM as mycobacteria are quite resistant to ammonium compounds. The present patient used to visit a public swimming pool very often. However, as a limitation of this report, we have not taken any sample from the pool water to culture for NTM.

NTM isolation from patients is a matter of debate whether it is a colonization or causative agent for infection. Only one sputum culture positivity for NTM is not adequate for disease diagnosis, but repeated sampling and culture testing are recommended. However, BALF culture is more reliable than sputum culture. In literature, there is a case that is diagnosed with pleural tissue culture. [12]

A wide range of therapy has been used in M lentiflavum cases, but optimal therapy has not been established, yet. However, it should be kept in mind that generally, the patient will not respond to standard antituberculous therapy. [5] Current guidelines recommend a minimum of 12-month combination therapy, which includes macrolide, ethambutol, and rifamycin. Susceptibility testing is recommended.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


[1.] Springer B, Wu WK, Bodmer T, Haase G, Pfyffer GE, Kroppenstedt RM, et al. Isolation and characterization of a unique group of slowly growing mycobacteria: Description of Mycobacterium lentiflavum sp. Nov. J Clin Microbiol 1996;34:1100-7.

[2.] Shamaei M, Marjani M, Farnia P, Tabarsi P, Mansouri D. Human infections due to Mycobacterium lentiflavum: First report in Iran. Iran J Microbiol 2010;2:27-9.

[3.] Tortoli E, Mattei R, Russo C, Scarparo C. Mycobacterium lentiflavum, an emerging pathogen? J Infect 2006;52:e185-7.

[4.] Cowman SA, Loebinger MR. Diagnosis of nontuberculous mycobacteria lung disease. Semin Respir Crit Care Med 2018;39:343-50.

[5.] Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, et al. An official ATS/IDSA statement: Diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Am J Respir Crit Care Med 2007;175:367-416.

[6.] Ford ES, Home DJ, Shah JA, Wallis CK, Fang FC, Hawn TR, et al. Species-specific risk factors, treatment decisions, and clinical outcomes for laboratory isolates of less common nontuberculous mycobacteria in Washington state. Ann Am Thorac Soc 2017;14:1129-38.

[7.] Duzgol M, Cavusoglu C, Kara A, Gulfidan G, Ayhan Y, Bayram N, et al. Mycobacterium lentiflavum infection in a patient with hyper-IgE recurrent infection syndrome: A case report. Infect Dis Clin Pract 2017;25:275-8.

[8.] Niobe SN, Bebear C, Clerc M, Pellegrin JL, Bebear C, Maugein J. Disseminated Mycobacterium lentiflavum infection in a human immunodeficiency virus-infected patient. J Clin Microbiol 2001;39:2030-2.

[9.] Yagi K, Morimoto K, Ishii M, Namkoong H, Okamori S, Asakura T, et al. Clinical characteristics of pulmonary Mycobacterium lentiflavum disease in adult patients. Int J Infect Dis 2018;67:65-9.

[10.] Phelippeau M, Dubus JC, Reynaud-Gaubert M, Gomez C, Stremler le Bel N, Bedotto M, et al. Prevalence of Mycobacterium lentiflavum in cystic fibrosis patients, France. BMC Pulm Med 2015;15:131.

[11.] Marshall HM, Carter R, Torbey MJ, Minion S, Tolson C, Sidjabat HE, et al. Mycobacterium lentiflavum in drinking water supplies, Australia. Emerg Infect Dis 2011;17:395-402.

[12.] Lee YC, Kim SB, Gang SJ, Park SY, Kim SR. Acute necrotizing pneumonia combined with parapneumonic effusion caused by Mycobacterium lentiflavum: A case report. BMC Infect Dis 2015;15:354.

Deniz Dogan Mulazimoglu, Hulya Simsek (1), Beyhan Qakar (2), Oya Kayacan


Deniz Dogan Mulazimoglu:

Hulya Simsek:

Beyhan Qakar:

Oya Kayacan:

Department of Pulmonology Faculty of Medicine, Ankara University, (2) 7th Tuberculosis Control Dispensary, Ankara, (1) Department of Medical Microbiology, Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey

Address for correspondence:

Dr. Deniz Dogan Mulazimoglu, Department of Pulmonology, Faculty of Medicine, Ankara University, Mamak St., Dikimevi, Ankara 06100, Turkey.


Received: 31-12-2018

Revised: 20-02-2019

Accepted: 28-02-2019

DOI: 10.4103/ejop.ejop_81_18
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Article Details
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Title Annotation:Case Report
Author:Mulazimoglu, Deniz Dogan; Simsek, Hulya; Qakar, Beyhan; Kayacan, Oya
Publication:Eurasian Journal of Pulmonology
Article Type:Clinical report
Geographic Code:7TURK
Date:May 1, 2019
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