Case Report

Ann Lab Med 2012; 32(4): 298-303

Published online July 1, 2012

Copyright © Korean Society for Laboratory Medicine.

Lung Infection Caused by Mycobacterium riyadhense Confused with Mycobacterium tuberculosis: The First Case in Korea

Jung-In Choi, M.D.1, Ji-Hun Lim, M.D.1, Sung-Ryul Kim, M.D.1, Seon Ho Lee, M.D.1, Jae-Sun Park, M.D.1,
Kwang Won Seo, M.D.2, Jae Bum Jeon, M.D.2, and Joseph Jeong, M.D.1

Departments of Laboratory Medicine1 and Internal Medicine2, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea

Correspondence to: Joseph Jeong
Department of Laboratory Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, 290-3 Jeonha 1-dong, Dong-gu, Ulsan 682-714, Korea
Tel: +82-52-250-7273
Fax: +82-52-250-8269

Received: November 24, 2011; Revised: February 10, 2012; Accepted: March 17, 2012

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


A slowly growing, non-chromogenic mycobacterial strain was isolated from sputum and bronchial lavage fluid samples of a patient presenting with productive cough, blood-tinged sputum, low-grade fever, and weakness. A positive acid-fast bacilli sputum smear result prompted the initiation of an anti-tuberculosis regimen. Multiplex real-time PCR showed a negative result for Mycobacterium tuberculosis complex and a positive result for nontuberculous mycobacteria. The DNA chip test confirmed this organism as a member of the genus Mycobacterium, but could not specify the species. Interestingly, the mycolic acid patterns obtained by HPLC nearly overlapped with those of M. simulans. The sequences of the Mycobacterium 16S rRNA gene and 16S-23S internal transcribed spacer region were unique and were found to have 100% similarity with those of M. riyadhense. After a review of the literature, we report this case as the first Korean case of M. riyadhense lung infection.

Keywords: Nontuberculous mycobacteria, Mycobacterium, Mycobacterium riyadhense, Mycobacterium simulans