An Unfavorable Outcome of M. chimaera Infection in Patient with Silicosis

Abstract

Mycobacterium chimaera is a slow-growing, nontuberculous mycobacterium (NTM) belonging to the Mycobacterium avium complex (MAC). It was identified as a unique species in 2004. Since 2013 it has been reported as a cause of disseminated infection in patients after cardiac surgeries. Only a few cases associated with underlying lung diseases have been noted. M. chimaera infection is characterized by ambiguous symptoms. There is no treatment with proven effectiveness, and it has a poor prognosis. Silicosis is a disease that can predispose to mycobacterial infection. Silica damages pulmonary macrophages, inhibiting their ability to kill mycobacteria. We present a case of M. chimaera infection in a patient with silicosis and without other comorbidities. To our knowledge, it is the first case of silicosis associated with M. chimaera disease. A 45-year-old man presented with a persistent low-grade fever. Based on the clinical and radiological picture, positive cultures, and histological examination, the nontuberculous mycobacterial disease was diagnosed. First, multidrug therapy according to the treatment guidelines for MAC was implemented, then antibiotics were administrated, based on drug sensitivity. Despite the treatment, eradication was not achieved and the patient died. The analysis of M. chimaera infection cases could contribute to developing recommendations and thus improve the prognosis.

Keywords: Mycobacterium chimaera; extracorporeal membrane oxygenation; nontuberculous mycobacterial disease; silicosis.

Figure 1

Posteroanterior chest X-ray (2015) shows multiple small diffuse well-defined nodules, confluent opacities in the upper zones and the middle right zone (arrow), hilar lymphadenopathy, and small right-sided pleural effusion (asterisk).

Figure 2

High-resolution computed tomography of the lungs (2015) shows numerous, small, well-defined nodules with a perilymphatic distribution and consolidations in the lung periphery (arrow).

Figure 3

Posteroanterior chest X-ray (2017) shows the evident progression of disseminated lung lesions, large opacities, and conglomerate masses in the upper and middle zones with retraction of hila.

Figure 4

CT scan (2017) shows diffuse nodules and bilateral conglomerate masses (arrows) associated with distortion of lung architecture.

Figure 5

The acid-fast rods of mycobacterium. Smear made from a colony, Ziehl-Neelsen stain.

Figure 6

The colony growth Mycobacterium chimaera on Löewenstein-Jensen solid medium.