Community-acquired pneumonia (CAP)

We determined the sequence of the intergenic spacer (IGS) 1 region, which is located between the 26S and 5S rRNA genes, in 25 species of the genus Trichosporon. IGS 1 sequences varied in length from 195 to 719 bp. Comparative sequence analysis suggested that the divergence of IGS 1 sequences has been greater than that of the internal transcribed spacer regions. We also identified five genotypes of T. asahii, which is a major causative agent of deep-seated trichosporonosis, based on the IGS 1 sequences of 43 strains. Most of the isolates that originated in Japan were of genotype 1, whereas the American isolates were of genotype 3 or 5. Our results suggest that analysis of IGS regions provides a powerful method to distinguish between phylogenetically closely related species and that a geographic substructure may exist among T. asahii clinical isolates.Fungal rRNA genes are tandemly repeated, with each repeat encoding 18S (small-subunit), 5.8S, and 26S (large-subunit) genes. Two other regions exist in each repeat: the internal transcribed spacer (ITS) region and the intergenic spacer (IGS) region (Fig. 1). Ribosomal DNA (rDNA) has been widely utilized for molecular systematics and the identification of microorganisms. The D1/D2 regions of 26S and ITS sequences have been used mainly to identify pathogenic fungi. At present, the 26S rDNA sequences of almost all yeasts, including nonpathogenic species, have been determined (3,7,8). The analysis of ITS sequences has been carried out mainly for pathogenic yeast species (1,5,9,10,16,19). Peterson and Kurtzman (13) and Sugita et al. (16) demonstrated that a single species showed less than 1% dissimilarity in either the ITS region or D1/D2 26S rDNA. However, these sequence analyses are sometimes incapable of distinguishing between phylogenetically closely related species, such as the three varieties of Cryptococcus neoformans. Although three varieties within a single species can be distinguished for each varietal level by ITS sequence analysis, the distinction is based on differences of only three or four nucleotides (20). Recently, Diaz et al. (2) and Sugita et al. (17) demonstrated that three varieties of C. neoformans were more clearly distinguished by analysis of IGS 1 and IGS 2 sequences than by ITS sequence analysis. Therefore, IGS sequence analysis appears to be a powerful tool for differentiating between phylogenetically very closely related species.

These results suggest that initial evaluation of serum KL-6 level can predict survival in patients with IPF.

No abstract

The present study was designed to evaluate the pathological and immunohistochemical findings of Mycobacterium avium intracellulare complex (MAC) lung infection.A retrospective study was performed in five cases with positive cultures for MAC in whom lung resections were performed between January 1989 and December 1996. A determination of whether or not MAC caused pulmonary disease was made using the 1997 criteria defined by the American Thoracic Society. In addition, MAC was cultured from all of the five lung specimens. Pathological and immunohistochemical findings as well as chest computed tomography (CT) findings were evaluated in these five patients.Pathological findings of bronchiectasis, bronchiolitis, centrilobular lesion, consolidation, cavity wall and nodules were demonstrated, respectively, in relation to chest CT findings. Extensive granuloma formation throughout the airways was clearly demonstrated. Immunohistochemical staining demonstrated: 1) epithelioid cells and giant cells; 2) myofibroblasts extensively infiltrating the cavity wall; and 3) B-cells detected in aggregates in the vicinity of the epithelioid granulomas.This study identified pathological and immunohistochemical characteristics of Mycobacterium avium complex infection relative to chest computed tomography findings and allowed the conclusion that bronchiectasis and bronchiolitis were definitely caused by Mycobacterium avium complex infection. Eur Respir J 1999; 13: 535±540.