Mycobacterium triplex pulmonary disease in immunocompetent host

The clinical significance of Mycobacterium triplex

OBJECTIVES

Mycobacterium triplex is a slow-growing nontuberculous mycobacteria (NTM) and is a rare cause of human disease. The pathogenicity, natural history and spectrum of disease is unknown. The aim of this study was to review the clinical features, outcomes and drug susceptibility testing (DST) of all M. triplex isolates in Queensland, Australia to guide management of this rare NTM infection in the future.

METHODS

This retrospective study included all patients who isolated M. triplex in Queensland, Australia from the 1st January 2000 to 31st December 2016. Clinical information was obtained from medical records to determine the clinical significance of isolates, natural history of disease and treatment outcomes. DST was performed on 15 isolates.

RESULTS

Forty-three patients (21 male) had positive cultures for M. triplex. Thirty-nine patients had isolates from pulmonary specimens and 17 (43.6%) met the American Thoracic Society criteria for NTM lung disease. Six patients with pulmonary infection received antimicrobial therapy with 5 patients demonstrating treatment success. Four patients had localised extrapulmonary disease and were cured with surgical management ± antimicrobial therapy. DST suggests 93% of isolates are susceptible to macrolides.

CONCLUSION

This is the largest case series of M. triplex isolates and confirms it is a rare human pathogen. Extrapulmonary disease responded well to surgical management. Treatment of M. triplex pulmonary disease is challenging, and the optimal antimicrobial regimen is unknown. However, the DST data suggests macrolide resistance is rare and macrolides should be included in treatment regimens.

Mycobacterium triplex pulmonary disease in an immunocompetent host: A case report and literature review

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The report describes a rare case of pulmonary disease due to M. triplex.

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The pulmonary lesion was discovered as an incidental finding on chest X-ray.

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The organism was identified by housekeeping gene sequencing analysis.

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The patient had a history of tuberculosis & non-tuberculous mycobacterial infection.

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The patient was treated with antimicrobials and the lesion was cured.

Mycobacterium triplex (M. triplex) is a bacterial species that can cause severe pulmonary diseases. Despite its clinical importance, only a few cases of M. triplex infection have been reported. Here, we present a rare case of pulmonary disease due to M. triplex in an immunocompetent patient who showed abnormal findings on chest X-ray and computed tomography scans. In this patient, the bacterium was identified by DNA sequencing analysis of the 16S rRNA and hsp65 genes. The patient was successfully treated with the appropriate antimicrobial agents. To put this case into the context of the current literature, we also reviewed other case reports of M. triplex infection.

Pacemaker pocket infection due to Mycobacterium goodii, a rapidly growing mycobacteria

A woman aged 74 years with an implanted dual-chamber pacemaker presented with pacemaker site infection after failing empiric antimicrobial therapy. The pathogen was later identified as Mycobacterium goodii, a rapidly growing mycobacteria species. The pacemaker was subsequently removed and the patient was treated with oral ciprofloxacin and doxycycline with clinical improvement. In this article, we describe a rare case of pacemaker site infection by M. goodii.

First detection of Mycobacterium triplex in Latin America

In this study we describe the first isolation of Mycobacterium triplex in Latin America. This species causes infections in humans, with very few reports from around the world. We isolated two sputum specimens of a patient with a 6-year history of human immunodeficiency and tuberculosis treatment failure. All tests used confirmed M. triplex and the patient responded well to drug therapy for 18months.

Cervical Lymphadenitis by Mycobacterium triplex in an Immunocompetent Child: Case Report and Review

Mycobacterium triplex was first described in 1996. This nontuberculous Mycobacterium causes a severe pulmonary disease in immunocompromised patients but it can involve also healthy patients. A literature search was made on the PubMed database and it produced only few cases of children with cervical lymphadenitis due to this Mycobacterium Triplex. We are describing a case of M. triplex cervical lymphadenitis in an immunocompetent child.