In vivo effects of citric acid/zwitterionic surfactant cleansing solution on rabbit sinus mucosa.

BACKGROUND: Chronic rhinosinusitis that is refractory to medical or surgical intervention may involve a particularly resistant form of infection known as a bacterial biofilm that is recalcitrant to antibiotics secondary to physical barrier characteristics. Recently, a novel sinus cleansing solution, citric acid/zwitterionic surfactant (CAZS) was shown to be extremely effective in disrupting biofilms in vitro. The purpose of this study was to determine the effects of CAZS on sinonasal epithelium In vivo compared with normal saline. METHODS: Indwelling catheters were placed into the right maxillary sinus of New Zealand white rabbits. CAZS solution or normal saline (10 mL) was instilled at a rate of 20 mL/minute into the sinus followed by aspiration. Rabbits were killed 1, 3, and 6 days after treatment. Mucosa from both maxillary sinuses was harvested and evaluated for physiological activity (ciliary beating) as well as morphological integrity of the epithelium by scanning electron microscopy. RESULTS: One day after treatment, beating cilia was evident with morphological analysis shown intact epithelium with 80-85% denudation of cilia compared with saline. Three days after treatment, ciliary activity was again noted with morphological evidence of persistent denuded cilia. By day 6 after treatment, the epithelium had regenerated cilia over the apical surface. Throughout the recovery period beating cilia was evident in CAZS-treated sinuses. CONCLUSION: This study shows that although CAZS acutely denudes respiratory cilia, the remaining cilia are active. Additionally, the epithelial barrier appears intact with active ciliogenesis, and reciliation of the mucosal surface occurring 6 days after treatment.

Prevalence of biofilm-forming bacteria in chronic rhinosinusitis.

BACKGROUND: Recently, biofilms have been implicated in the pathogenesis of recalcitrant chronic rhinosinusitis (CRS). We sought to determine the prevalence of biofilm-forming cultures obtained from patients with CRS and clinical factors that may contribute to biofilm formation. METHODS: Endoscopically guided sinonasal cultures were obtained in duplicate from CRS patients with evidence of mucopurulence. Bacterial swabs were sent for microbiological characterization and were simultaneously evaluated for biofilm-forming capacity by a modified Calgary Biofilm Detection Assay. Biofilm formation was based on concomitant values of biofilm-forming Pseudomonas aeruginosa O1 (PAO1) (positive control) and non-biofilm-forming mutants sad-31 (type IV pili) and sad-36 (flagella K; negative control). Samples, with growth greater than the sad-31 mutant, were designated as biofilm formers. RESULTS: Sinonasal cultures were obtained from 157 consecutive patients (83 female patients) over a 4-month period. Forty-five samples (28.6%) showed biofilm formation. Among patients with a prior history of functional endoscopic sinus surgery (FESS), 30.7% (n = 42) showed biofilm growth. For patients naive to surgical intervention (n = 20), only 15% showed biofilm formation. A positive, statistically significant correlation existed between biofilm formation and number of prior FESS procedures. Polymicrobial cultures, Pseudomonas aeruginosa, and/or Staphylococcus aureus comprised 71% of samples. Chi-squared analysis showed an association with prior infections, but not with any pharmacologic therapy or comorbidies. CONCLUSION: We show a high percentage of CRS patients (28.6%) whose sinonasal mucopurulence has biofilm-forming capacity. Postsurgical patients had a high prevalence of biofilm-forming bacteria, a possible reflection of the severe nature of their disease. Additional studies are warranted.