Background: Due to the predisposing conditions in patients with cystic fibrosis (CF) caused by defective mucociliary clearance facilitating colonization and invasion with Candida species has dramatically increased. Traditional methods for identifying problems are imminent and time-consuming. Therefore, molecular techniques utilizing amplification of target DNA provide quick and precise methods for the diagnosis and identification of Candida species. Therefore, the aim of the current study was to identify the most medically common isolated Candida species from the air way of CF patients by PCR-RFLP and amplification of HWP1 gene.

Materials and Methods: A total of 42 CF patients presenting symptoms who referred to pediatric respiratory diseases research center were screened for the presence of Candida spp. The isolates initially were phenotypically identified and confirmed by molecular approaches based on restriction fragment length polymorphism ( PCR -RFLP) for the discrimination of C. albicans of non-albicans and the amplification of HWP1 gene for the discrimination of C. albicans from C. dubliniensis and C. africana was conducted.

Results: The results show that C. albicans was the most frequently isolated species (83.8%) followed by non-albicans included C. parapsilosis (7.1%), C. glabrata (3.2%), and C. tropicalis (3.2%). The restriction patterns of each Candida species were perfectly specific. Since MspI could not discriminate between the three morphological related species, C. albicans, C. dubliniensis and C. africana, we used PCR amplification of HWP1 gene, which (7.1%) species from C. albicans identified as C. dubliniensis, however C. africana strains were not found.

Conclusion: The present study found that C. albicans as predominant species wereisolated from the CF patients. It could be concluded that molecular diagnostic methods are reliable and would be useful for the identification of medically important Candida species in clinical samples . Therefore, considerable attention has been paid to the prevention and treatment of microbial growth, which has resulted in the improvement of patient management.