Molecular Characterization of Fungal Colonization on the Provox™ Tracheoesophageal Voice Prosthesis in Post Laryngectomy Patients.

BACKGROUND: Tracheoesophageal voice prostheses (TVPs) have been the gold standard in rehabilitation, after laryngectomy, producing faster and premier voicing towards esophageal speech. Fungal colonization shortens the device's lifetime and leads to prosthesis dysfunction, leakage, and subsequent respiratory infection. Therefore, in the current study, we aimed to investigate the fungal colonization patterns and to propose prophylactic measures that shall increase the longevity of voice prosthesis. METHODS: Failed TVPs were removed - due to leakage and/or aspiration - from 66 post laryngectomy patients and examined. They were referred to Amiralam and Rasoul Hospital, the main centers of Ear, Nose, and Throat in Tehran, Iran from April 2018 to January 2020. Fungal colonization patterns were assessed using DNA sequencing techniques. Furthermore, the susceptibility to fluconazole, amphotericin B, nystatin, and white vinegar was evaluated according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. RESULTS: Resident fungal species from the upper airways colonized all the 66 TVPs (100%). Diabetes (31%) and smoking (98%) were the predominant underlying disease and predisposing factors, respectively. Among the 79 fungal agents isolated from the 66 TVPs, Candida glabrata (n=25, 31.7%) was the most common. A significant reduction in minimum inhibitory concentration (MIC) values were observed for white vinegar when used alone (P<0.05). CONCLUSION: White vinegar at a very low concentration could decrease the amount of fungal colonization on TVPs without any adverse effects; its wide accessibility and affordability ensure a decrease in the overall health cost.

Effect of thymoquinone on Fusobacterium nucleatum­associated biofilm and inflammation.

Periodontitis affects oral tissues and induces systemic inflammation, which increases the risk of cardiovascular disease and metabolic syndrome. Subgingival plaque accumulation is a trigger of periodontitis. Fusobacterium nucleatum (FN) contributes to subgingival biofilm complexity by intercalating with early and late bacterial colonizers on tooth surfaces. In addition, inflammatory responses to FN are associated with the progression of periodontitis. Nigella sativa Lin. seed, which is known as black cumin (BC), has been used as a herbal medicine to treat ailments such as asthma and infectious diseases. The current study examined the inhibitory effect of BC oil and its active constituents, thymol (TM) and thymoquinone (TQ), on FN­associated biofilm and inflammation. FN­containing biofilms were prepared by co­cultivation with an early dental colonizer, Actinomyces naeslundii (AN). The stability and biomass of FN/AN dual species biofilms were significantly higher compared with FN alone. This effect was retained even with prefixed cells, indicating that FN/AN co­aggregation is mediated by physicochemical interactions with cell surface molecules. FN/AN biofilm formation was significantly inhibited by 0.1% TM or TQ. Confocal laser scanning microscopy indicated that treatment of preformed FN/AN biofilm with 0.01% of BC, TM or TQ significantly reduced biofilm thickness, and TQ demonstrated a cleansing effect equivalent to that of isopropyl methylphenol. TQ dose­dependently suppressed TNF­α production from a human monocytic cell line, THP­1 exposed to FN, yet showed no toxicity to THP­1 cells. These results indicated that oral hygiene care using TQ could reduce FN­associated biofilm and inflammation in gingival tissue.