Chronic Rhinosinusitis: MALDI-TOF Mass Spectrometry Microbiological Diagnosis and Electron Microscopy Analysis; Experience of the 2nd Otorhinolaryngology Clinic of Cluj-Napoca, Romania

Abstract

(1) Background: Chronic rhinosinusitis (CRS) represents a wide range of infectious-inflammatory processes affecting, simultaneously, the nose and paranasal sinuses mucosa. The paper presents outcomes of the investigation of CRS microbiological characteristics in a group of 32 patients. (2) Methods: The purulent samples were collected during functional endoscopic sinus surgery. Agar plates were incubated and examined. All types of colonies were identified using Matrix-Assisted Laser Desorption - Ionisation-Time of Flight Mass Spectrometry (MALDI-TOF MS). For scanning electron microscopy, samples were fixed and sputter-coated with 10 nm gold and analyzed using a scanning electron microscope. For transmission electron microscopy, samples were fixed, postfixed, and dehydrated. After polymerization, ultrathin sections were collected on carbon coated copper grids and analyzed with Jeol JEM1010 TEM. (3) Results: Positive microbiological diagnosis was obtained in 62.5% of cases. The most frequent species found are Staphylococcus aureus and Streptococcus constellatus subsp. pharyngis. Corynebacterium aurimucosum and Eggerthia catenaformis were unreported species in CRS until the present. Biofilm was evidenced in 43.7% of sinus mucosa samples. Ciliary disorientation, atrophy, and no ciliated cells were also identified. (4) Conclusion: The microbial factor—pathogen or opportunistic—is one of the most important pathological links in chronic rhinosinusitis. MALDI-TOF MS allows easily and quickly identification of germs.