Clinical significance of microbial growth on the surfaces of silicone tubes removed from dacryocystorhinostomy patients

Purpose: To investigate the bacterial infection of silicone tubes removed from patients who underwent dacryocystorhinostomy (DCR) and assess the correlation between the culture results and postoperative clinical features. Design: Retrospective observational case series. Methods: Consecutive epiphora patients who underwent external or endoscopic DCR surgery were reviewed. The postoperatively removed silicone tubes were cultured. Preoperative canalicular stenosis and nasal septal hypertrophy, postoperative inflammation, membranous obstruction of nasal mucosa, and the duration of silicone intubation were reviewed. Correlations between the results of bacterial culture and clinical features were verified. Results: A total of 39 silicone tubes removed from 33 patients were cultured: 34 (87.2%) external DCR cases and 5 (12.8%) endoscopic DCR. Culture provided positive results in 37 cases (94.9%). A total of 52 isolates were identified: 73.1% gram-positive bacteria, 23.1% gram-negative bacteria, and 3.8% fungi. Of the gram-positive organisms, 73.9% were Staphylococcus aureus. Most of the gram-negative organisms were Pseudomonas aeruginosa, found in 5 eyes. The time of tube placement was significantly longer in cases with P. aeruginosa than in those with other bacteria (P =.001). The rate of pseudomonas infection was significantly higher in cases with revision than in those without revision (P =.001). Final surgical failure was significantly related with canalicular stenosis (P =.017), pus discharge at extubation (P <.001), history of endoscopic revision (P =.001), and pseudomonal infection (P =.010). Conclusions: Various bacterial species were cultured from removed silicone tubes. Although many of them were normal flora, P. aeruginosa infection showed significant relation with membranous obstruction of nasal mucosa, prolonged silicone intubation, and surgical failure.