Search

Purpose: To investigate the pathogens and biofilms responsible for clinically significant infection of silicone stents implanted within the lacrimal system., Methods: Retrospective review of culture results and patient demographics for all silicone lacrimal stents removed early for clinically significant infection and sent to the Bascom Palmer Microbiology Laboratory through the end of year 2010. As a control, routinely removed, clinically noninfected stents from the same institution were prospectively sent for culture over a 6-month period. Four clinically infected and 6 clinically noninfected stents showing mucus within the lumen at removal were sent for scanning electron microscopy. Images were randomized and graded by a microbiologist for the presence of organisms, matrix deposits, organisms within matrix, and overall impression of significant biofilm formation., Results: Nineteen stents were included in the study; 100% of clinically infected (n = 10) and noninfected (n = 9) stents were culture positive. Culture positivity for nontuberculous mycobacterium was found in 90% of infected stents and none of the noninfected stents (p < 0.001). Of infected stents, 50% grew Gram-positive organisms compared with 89% of noninfected stents (p = 0.07). Fifty percent of infected versus 67% of noninfected stents were culture positive for Gram-negative organisms (p = 0.46). Electron microscopy of stents revealed organisms consistent with culture results (size, shape) in planktonic and biofilm form. Masked observer image grading revealed a statistically significant higher amount of organism and biofilm on infected versus noninfected specimen., Conclusion: Nontuberculous mycobacteria comprise the primary pathogens responsible for clinically significant infection of silicone stents in the lacrimal system in South Florida. Robust biofilm production by this organism likely plays a role in pathogenesis. Further research into biofilm-related lacrimal implant infection may aid in the development of useful prevention and treatment strategies.

Purpose: To investigate microbiologic trends and role of biofilm on periorbital biomaterials surgically explanted for recalcitrant infection., Methods: A search of the Bascom Palmer Eye Institute, University of Miami Miller School of Medicine microbiology laboratory electronic database was conducted from 1980 to 2010. Culture results were analyzed from submitted periorbital biomaterials explanted for nonresolving infections or exposure. Random select samples cultured during the study were sent for electron microscopy., Results: Twenty-one explanted biomaterials were identified from 18 patients. Five orbital plate implants included 2 made of nylon, 1 of porous polyethylene, 1 of silicone, and 1 metallic. Of 4 anophthalmic socket sphere implants, 2 were silicone, 1 was porous polyethylene, and 1 was poly-2-hydroxyethyl methacrylate. Lacrimal intubation devices included 10 silicone stents and 2 pyrex glass Jones tubes. All biomaterials were culture positive with 40 total isolates identified. The most common organisms overall were Mycobacterium chelonae (N = 9), Staphylococcus aureus (N = 8), and Pseudomonas aeruginosa (N = 3). One hundred percent of orbital spheres had Gram-positive organisms, 90% of lacrimal silicone stents grew atypical mycobacterium, and 60% of orbital plates were culture positive for yeast species. Mixed organism growth was documented on 58% of the specimens. Ten of 12 implants (83%) examined with electron microscopy exhibited organisms encased in glycocalyx, suggestive of biofilm., Conclusions: A diverse array of microorganisms can colonize biomaterials implanted within the orbit and lacrimal drainage system. The authors' study showed that the majority of infected periocular and orbital alloplastic implants display biofilm when studied with electron microscopy (83%). The cultured organism type depended on the implant location and composition. Most infected silicone lacrimal stents grew atypical mycobacterium, whereas infected orbital fracture repair plates demonstrated yeast species. Biofilms are known to be antibiotic resistant, explaining the need to explant most infected alloplastic implants. Further research concerning treatment of biofilms may prevent explantation and improve surgical outcomes.