Background: Mucormycosis is a life-threatening fungal infection and accurate diagnosis based on conventional methods remains a challenge for physicians. Molecular diagnosis may greatly help diagnosis and species identification of invasive mucormycosis.
Objectives: We aimed to study whether molecular methods assist diagnosis and identification of Mucorales in cases of suspected invasive mucormycosis.
 Patients/Methods: All patients with suspected invasive fungal infection according to the EORTC/MSG criteria admitted in Hospitals in Northern Iran affiliated with Mazandaran University between April 2015 and August 2017 were included. In addition, formalin-fixed paraffin-embedded (FFPE) samples of histopathologically proven mucormycosis cases during the same period were studied. PCR assays targeting the 18S rDNA of Mucorales and ITS region were performed and the PCR products were then sequenced.
Results: Of 63 patients with suspected invasive fungal infections hospitalized during April 2015 and August 2017, 9 (14.3%) cases of definite mucormycosis were identified. While the culture was positive only in 5 (7.9%) cases, PCR was positive in all 9 cases of mucormycosis. Ten of 18 (55.6%) FFPE samples were positive with PCR. Overall, Mucorales PCR was positive in 19 of 27 (70.4%) samples. Species of Mucorales were Rhizopus oryzae in 12 (63.1%) cases, Rhizopus oryzae / Amylomyces rouxii in 6 (31.6%) cases and Rhizopus stolonifer in one case (5.3%). Among 27 cases of molecularly diagnosed mucormycosis 23 (85.2%) cases were rhino-cerebral mucormycosis, 2 (7.4%) cases were disseminated and 2 (7.4%) cases cutaneous. Diabetes mellitus (70.4%) and neutropenia (63.0%) were the main risk factors in this cohort of patients with invasive mucormycosis.
Conclusions: We found that semi-nested PCR targeting 18S rDNA region of Mucorales is useful for detection of invasive mucormycosis and the Mucorales species causing it. In North area of Iran mucormycosis is more common in diabetic patients and rhino-cerebral form of diseases is more prevalent. Rhizopus oryzae appears to be the predominant species causing invasive mucormycosis.

5 / Polymerase chain reaction (PCR) diagnosis and identification of mucormycosis in patients with suspected invasive fungal infection