Sequence Base Identification of Respiratory Mucormycosis

Background: Mucormycosis is an uncommon fungal infection in immunocompromised patients during the past decades. Identification of causative agents could play an important role in the management of infected patients. Objectives: The aim of the present study was the identification of etiologic agents of respiratory tract mucormycosis, based on sequencing methods. Methods: Sinus tissue, bronchoalveolar lavage, and blood samples from the patients with suspected invasive fungal diseases were collected. Sinus tissue and bronchoalveolar lavage were examined by microscopic examination and cultured on Sabouraud dextrose agar. Blood samples were cultured on BACTEC medium. Semi-nested polymerase chain reaction (PCR) for diagnosis of mucormycosis was performed on samples, and products of positive PCR were sequenced and manually viewed with Chromas version 2.24 software. Pathology reports were collected from patients’ files. Results: Direct microscopic examinations, culture, and semi-nested PCR were positive in 11.7% (19/163), 6.7% (11/163), and 10.4% (17/163) of patients, respectively. None of the blood cultures were positive for Mucorales. The etiologic agents were Rhizopus oryzae (10 cases), R. microsporus (5 cases), and new species (2 cases). This new sequence (645 bp) was published in Gene bank and European Nucleotide archive of EMBL-EBI, and demonstrated 98% identity with Lichtheimia (Absidia) corymbifera genus. Conclusions: Management of mucormycosis has an important role in the treatment and outcome of such infections. Molecular assay and DNA sequencing could be used in parallel with conventional mycology techniques to identify Mucorales and for best management of respective infections.