Abstract
Purpose: :
Punctal occlusion is commonly used in the management of dry eye syndrome. Recent studies have demonstrated an association of punctal plugs and intracanalicular devices with biofilm formation and clinical infection. The purpose of our study is to evaluate these devices for biofilm formation using a novel culture technique and to further characterize the microorganisms that form these biofilms.
Methods: :
Patients at the University of North Carolina Ophthalmology clinic underwent removal of punctal plugs and intracanalicular stents for routine clinical indications over a nine-month period from December 2008 to September 2009. The devices were submitted for microbiology culture before and after water-bath sonication to loosen adherent microorganisms. Main outcome measures were clinical signs and symptoms of lacrimal infection, culture positivity, identification of isolated microorganisms, and enhanced recovery of microorganisms from culture after sonication. This is a prospective, observational study.
Results: :
54 patients were included in the study (40 women, 14 men; average age 58 years ± 16.1 [SD] years). 86 devices (81 punctal plugs and 5 monocanalicular stents) were submitted for culture. The devices were in place an average of 76.5 days ± 53.3 [SD] days. None of the patients had clinical evidence of lacrimal infection. Cultures were positive in 36 of 86 samples (42%). 56% were positive for oropharyngeal flora. 19% were positive for skin flora. Gram negative rods were isolated in 14% of samples. Anaerobes and Stenotrophomonas maltophilia were each isolated in 11% of samples. Nocardia was isolated in 6% of samples. One sample grew Mycobacterium chelonae. In 5 of the 86 samples (6%), sonication enhanced the recovery of microorganisms from culture by a ten-fold or more increase in the number of colony-forming units.
Conclusions: :
Punctal plugs and intracanalicular devices can become colonized with bacteria and form biofilms composed of oropharyngeal flora, skin flora, and other rare but clinically significant pathogens. Water-bath sonication did not aid in the enhanced detection of biofilms.
Keywords: cornea: tears/tear film/dry eye • bacterial disease