Isolation and Identification of Geosmithia argillacea from a Fungal Ball in the Lung of a Tuberculosis Patient
A 44-yr-old Korean man with recurrent pulmonary infection was admitted to the hospital for elective lung surgery. He was diagnosed with pulmonary tuberculosis at the age of 18; subsequently, he received antituberculous therapy and was cured. However, hemoptysis occurred 4 yr later due to the development of pulmonary aspergilloma, and a right upper lobectomy was performed. In July 2007, the hemoptysis recurred and nontuberculous Mycobacterium (NTM) species were detected in the sputum sample. The treatment for this NTM infection lasted for 2 yr. In November 2009, on high resolution computed tomography (HRCT) of the chest, and a newly formed foreign body, with features suggestive of an intracavitary fungal ball, was noted in his right lung. Mycobacterium tuberculosis was also detected in the sputum sample, and he received antituberculous medication for 9 months.\nSeveral chest HRCT images taken between December 2010 and April 2011 revealed an increase in the size of the fungal ball, suggesting chronic necrotizing pulmonary aspergillosis (). Results of laboratory investigations were as follows: hemoglobin, 12.4 g/dL; white blood cell count, 6.03×109/L (50% segmented neutrophils, 32% lymphocytes, 16% monocytes, and 2% eosinophils). Serum electrolyte concentrations, liver function test results, and creatinine and glucose levels were all within the reference ranges. The serum sample was strongly positive for antibodies to Aspergillus, as determined by an enzyme immunoassay (>200 U/mL; positive cut-off: >12 U/mL). However, negative results were obtained for serum Aspergillus galactomannan. After the administration of antifungal therapy (itraconazole), the lesion was surgically resected in April 2011. Wide-wedge resection of the superior segment of the right lower lobe was performed along with the removal of the fungal ball. Simultaneously, lung tissue specimens were obtained for culture and pathology. Pathological study of the lung tissue revealed that the fungal ball was composed of hyphae, and therefore it was identified as an aspergilloma. Pathological evaluation revealed neither the presence of fungus in the lung parenchyma nor any evidence of invasive mycosis.\nLung tissue specimens were cultured on Sabouraud dextrose agar for 3 weeks, at a temperature of 30℃ for the first 2 days, and at room temperature (25℃) thereafter. Species was identified according to macro- and micro-morphological criteria. Macroscopic analysis revealed that the colonies formed were cream to beige in color, with no color on the reverse side (). Growth was slow and restricted at room temperature, but was enhanced at 30℃, with colonies reaching 2-3 cm in diameter after 10 days at this temperature. Microscopic analysis revealed the presence of hyaline, rough-walled, septate, and often-branched conidiophores (). These conidiophores bore biverticillate- or triverticillate-asymmetrical penicilli and had phialides with a tapering tip that were parallel to the axis. Conidia were smooth-walled, hyaline, and cylindrical to ellipsoidal. On the basis of these microscopic characteristics, it was assumed that the fungal ball was composed of a species of Penicillium. However, the macroscopic features were not compatible with those of Penicillium. Penicillium species are characterized by brush-shaped, round conidia and bluish-green colonies with a white border []. On the other hand, Paecilomyces was also excluded because the observed phialides were parallel to the axis of the conidiophores and were not bent away from the axis. Most importantly, Penicillium and Paecilomyces grow rapidly at room temperature.\nTherefore, molecular identification was performed by sequencing the ITS region and β-tubulin genes. The ITS region and the β-tubulin gene fragments were amplified and sequenced by standard methods, according to the CLSI guidelines []. This was followed by sequence comparison with the GenBank (NCBI) () database using the basic local alignment search tool (BLAST) algorithm. The BLAST search revealed that the partial ITS sequence showed a 100% (420/420) similarity with that of the G. argillacea strain CGDGA6 (accession no. HQ246728.1, #475-56), and a 97.1% (409/421) similarity with that of the G. argillacea type strain CBS 101.69 (accession no. JF417491.1, #497-79). Moreover, the β-tubulin gene sequence showed a 99.8% (423/424) similarity with that of the G. argillacea DTO 49D4 strain (accession no. GU968696.1, #1-424) and a 97.2% (424/436) similarity with that of the G. argillacea type strain CBS 101.69 (accession no. JF417491.1, #1-435). On the basis of these results, we concluded that G. argillacea was the species that was most likely responsible for the formation of fungal ball.\nA phylogenetic tree was constructed using the neighbor-joining method on the basis of the results of the comparative sequence analysis of the ITS region (). Phylogenetic and molecular evolutionary analyses were conducted using the Molecular Evolutionary Genetics Analysis (MEGA) software version 5.0 () [], and a subline related to Penicillium and Paecilomyces spp. was obtained, which are both similar to G. argillacea in microscopic findings.\nItraconazole was continued for another 2 months after surgery. Thereafter, the patient had a favorable clinical course without recurrence of symptoms or sequelae.