Investigation of Fungal Colonization Among Iranian Patients with Idiopathic Pulmonary Fibrosis; Molecular Identification and Antifungal Susceptibility Pattern

Abstract

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease. In patients with lung tissue damage, fungal colonization leads to persistent infection. It is expected for there to be an association between fungal agents and etiology of IPF. Objectives: The aim of this study was to investigate the prevalence and molecular identification of fungal species isolated from IPF patients for the first time in Iran. Also, in vitro anti-fungal susceptibility testing of isolates was demonstrated. Methods: Forty nasopharyngeal (NP) swabs or bronchoalveolar lavage (BAL) samples were obtained from Iranian patients with IPF, who were diagnosed by a sophisticated practitioner from year 2015 to 2016 (Tehran, Iran). Direct examination of samples was carried out using hydroxide potassium (KOH) for detection of fungal elements. The specimens were cultured on Sabauroud Dextrose Agar (SDA) medium. Conventional methods, including polymerase chain reaction (PCR) and sequencing, were carried out for identification of fungal species. Indeed, antifungal susceptibility testing of yeast isolates was conducted according to Clinical Laboratory Standards Institute (CLSI M27-S3 and S4) protocol. The data was analysed using SPSS sofware version 20. Results: Of 40 IPF patients, 22 (55%) were female and 18 (45%) were male. Seven (17.5%) of IPF patients were positive for fungal species as follows; four (10%) Candida albicans (C. albicans), two (5%) Candida glabrata (C. glabrata), and one (2.5%) Aspergillus fumigatus (A. fumigatus) were identified using the culture and PCR technique. A significant correlation was found between C. albicans colonization in upper respiratory system tract and presence of underlying disease in IPF patients (P < 0.05). Antifungal susceptibility testing showed that all C. albicans isolates were resistant to itraconazole, whereas three (75%) C. albicans were resistant to amphoterecin B. It was found that three (75%) and one (25%) C. albicans isolate were susceptible dose dependantly and resistant to fluconazole, respectively. Morever, C. glabrata isolates were resistant to fluconazole, itraconazole, and amphotricin B. Conclusions: Taken together, fungal species were detected in 17.5% of IPF patients. Resistance of Candida species to antifungal agents is growing, therefore isolation, identification, and antifungal susceptibility testing of fungal elements in IPF patients are necessary for appropriate treatment. However, determining an association between the fungal agents and devasting form of pulmonary fibrosis requires further investigation in the future.