First Case of Pulmonary Mycobacterium parascrofulaceum Infection in a Patient With Bronchiectasis in Korea

Dear Editor Mycobacterium parascrofulaceum is a member of slow-growing scotochromogenic nontuberculous mycobacteria (NTM) that can cause opportunistic infections in immunocompromised patients [1]. Only a few clinical infections with this strain have been reported to date [1-4]. We describe a case of M. parascrofulaceum pulmonary infection in a patient with bronchiectasis. To our knowledge, this is the first case of M. parascrofulaceum infection in Korea. A 65-yr-old man was referred to our hospital because of recurrent hemoptysis and prulent sputum for two days. He had a history of stomach cancer that had been treated by using total gastrectomy with Billroth II anastomosis and chemotherapy seven years ago; at that time, he was diagnosed as having bronchiectasis. Our laboratory tests revealed peripheral blood leukocyte counts of 6.48×10/L with 81.2% neutrophils. Chest computed tomography revealed no interval changes in the preexisting bronchiectasis of the lower left lobe of the lung. Nonetheless, new peribronchial infiltration and centrilobular nodules were found in the middle right lobe and lower left lobe. Acid-fast bacillus (AFB) staining, qualitative real-time PCR for Mycobacterium tuberculosis (COBAS TaqMan MTB Test; Roche, Basel, Switzerland), and nested PCR for NTM (MTB & NTM PCR Kit; BioSewoom Inc., Seoul, Korea) in the expectorated-sputum specimens all tested negative. Sputum cultures in liquid media were performed in triplicate by using the Mycobacteria Growth Indicator Tube System (MGIT, Becton, Dickinson and Company, Franklin Lakes, NJ, USA), and positive results were obtained from two cultures. For species identification, a PCR-based reverse line blot hybridization assay for the ITS gene (AdvanSure Mycobacteria GenoBlot Assay; LG Life Sciences, Seoul, Korea) was performed on both culture isolates, revealing poor discrimination of species (Mycobacterium lentiflavum/Mycobacterium genavense). For definitive species identification, sequencing analysis of the 16S rRNA, hsp65, and rpoB genes was performed. Primers used for PCR are shown in Table 1 [5-7]. 16S rRNA sequences obtained were searched against publicly available databases by using the basic local alignment search tool (BLAST) [8] and EzTaxon [9]. When the sequences were submitted to BLAST, both culture isolates revealed 99.74% similarity (767/769 bp) with M. parascrofulaceum HSC68. The next closest match was M. parascrofulaceum ATCC BAA-614 with similarity of 99.61% (776/779 bp). In EzTaxon, the isolates exhibited 99.36% similarity (773/778 bp) with M. parascrofulaceum ATCC BAA-614 followed by M. eu-