Pulmonary infection by Mycobacterium riyadhense: first case report in United Arab Emirates

Abstract

Mycobacterium riyadhense is an emerging slowly growing species that belongs to the group of nontuberculous mycobacteria (NTM) with approximately 20 cases reported worldwide. We highlight the first case of pulmonary infection by Mycobacterium riyadhense in United Arab Emirates (UAE). A 44-year-old female presented with chronic productive cough; a bronchial breathing pattern was appreciated on auscultation of her right upper lung. She was treated multiple times with allergic medications and antibiotics. Thorough investigations revealed Mycobacterium riyadhense and antitubercular drugs were started, eventually she was cured, however she had multiple relapses later. This case report holds a significant potential to make considerable contribution to the diagnosis of NTM, primarily because it presents the first documented case in UAE, as well as insights on how to address possible similar cases in the future.

Keywords: Mycobacterium riyadhense; antitubercular drugs; chronic cough; non-tuberculous mycobacteria; pulmonary cavity.

Figure 1

A well-defined cavity in the right upper lung measuring 4.5 cm and patchy consolidation in the left upper and middle lobes in November 2021 (A). Over time, the cavity reduced in size to 3.5 cm then to 3.2 cm with regression of the infiltrates in the left upper lobe in December 2022 (B).

Figure 2

CT shows an increase in the size of right upper lung cavity, from 3.2 cm on 31st August 2022 (A), to 4.5 cm on 16th January 2023 (B). In the CT image, A stands for Anterior, and P stands for Posterior.

Figure 3

In August 2022, CT shows bronchiectasis with micronodular infiltrates with a “tree-in-bud” pattern in the right lower lobe and left lingula (A), that have regressed over time in January 2023 (B).