PCR Analysis of Microorganisms in Chronic Rhinosinusitis with Nasal Polyps

Background: Chronic rhinosinusitis (CRS) with nasal polyps is characterized by tissue eosinophilia, which is speculated to be related to Staphylococcus superantigen and fungus, in European and U.S patients. However, Japanese patients with CRS with nasal polyps showed two distinct phenotypes of eosinophilic and neutrophilic inflammation (Hirotsu et al., 2011).We attempted to analyze the microorganisms from nasal polyps of Japanese patients by PCR method.

Methods: Eleven specimens of nasal polyps with CRS were collected for examination by endoscopic sinus surgery.  All specimens were treated with 70% ethanol and physiologic saline to eliminate microorganisms outside of the nasal polyps. Bacterial and fungal culture was performed for 2 weeks using five different culture media. We detected 16SrRNA bacteria and 18SrDNA-ITS-26SrDNA  fungus, and  then identified species of microorganisms by direct-sequence. In addition, the number of eosinophils in the nasal polyps was counted.

Results: No bacteria or fungus were recovered from any of the nasal polyps by culture medium. By the PCR analysis, DNA for bacteria could not be detected, whereas 7 samples of the nasal polyps showed amplification of fungal DNA such as Candida parapsilosis, Candida glabrata, and Rhodotorula etc. Grocott dyeing for the nasal polyps, however, showed no intracellular presence of fungus. The number of the eosinophils in the nasal poly with the patients with the presence of fungal DNA (240±191) was significantly (P<0.05)higher than that in the absence (56±40).

Conclusions: The present study suggests the participation of fungus in eosinophilic CRS with nasal polyps.