Laboratory approach for detection of non-invasive fungal rhinosinusitis: A case-control study

Abstract

Noninvasive fungal rhinosinustis is problematic being resistant to traditional medical treatment. Mycology laboratory work helps solving this issue. This case control study was designed to supplement the lacking information about the frequency of noninvasive fungal rhinosinusitis in our locality and identify fungal species responsible for this condition in Zagazig University Hospitals. In addition, to evaluate the role of microscopic examination, antigen detection and PCR in comparison to culture technique in diagnosis. Sinus material was collected from seventy eight cases represented clinically and radiologically with noninvasive fungal rhinosinusitis from June 2013 to September 2015. A control group 78 subjects with healthy sinuses from whom nasal smears were obtained. Samples were processed in Mycology Unit and examined microscopically in 10% KOH preparations. Lactophenol cotton blue slide preparations were examined for microscopic structures as hyphae and conidia. PCR amplification of the extracted DNA was performed using fungal universal primers for amplification of 28 S rDNA genes. Results: Microscopic examination revealed hyphae and fruiting bodies in 37 (47.4% of the cases). Culture diagnosed 36 FRS patients. Aspergillus fumigatus was the most frequently isolated from fungal rhino sinusitis (52.7 %) of cases, followed by Penicillium spp. in 22.2%. PCR amplification exhibits the same sensitivity and specificity as those demonstrated by microscopic examination (100% and 97.3% respectively). ELISA of Aspergillus galactomannan (GM) antigen lacked sensitivity (58.3%), with a higher specificity (100%). Conclusion: It is concluded that an experienced mycological confirmation especially, direct microscopic examination of clinically suspected noninvasive FRS cases is necessary for a final diagnosis. Key words: Rhinosinusitis; fungus; KOH; galactomannan; PCRRunning Title: Fungal rhinosinusitis mycology lab