Proteus mirabilis and its role in dacryocystitis

Dacryocystitis is a common inflammation of the lacrimal sac, usually from an underlying bacterial infection. Most cases can be attributed to common ocular flora such as Staphylococcus aureus or Streptococcus pneumoniae; however, uncommon bacterial causes such as Proteus mirabilis can still occur. P. mirabilis is a gram-negative bacillus that is found abundantly in people who have undergone long-term catheterization and is uncommonly found in or around the eyes except in people who have undergone long-term catheterization. Proteus species can cause conjunctivitis, canaliculitis, and dacryocystitis and have the ability to manifest into preseptal cellulitis; therefore, timely recognition and treatment are important to prevent potential further complications.

An 84-year-old white man had several recurrences of acute dacryocystitis that had marginal improvement with empiric antibiotic treatment. Resultant culture of the ocular discharge revealed an uncommon bacterium, P. mirabilis. Successful dosing of oral antibiotics resolved the infection but ultimately the patient required an external dacryocystorhinostomy (DCR) procedure to maintain patency of the nasolacrimal lacrimal system and prevent recurrence. At 3 months after external DCR, the patient was symptom free with no recurrences.

Dacryocystitis has a distinctive clinical presentation and is usually easily treated when appropriate oral antibiotics are directed at the underlying pathogen. In nonresponsive cases, culturing of the ocular discharge should be performed to identify the underlying pathogen. Cases of dacryocystitis caused by Proteus species are usually responsive to several standard antibiotics used orally in eye care; however, culturing and susceptibility testing can streamline the diagnostic and management sequence considerably in unclear or unresponsive cases. Typically, patients with dacryocystitis return to normal after appropriate treatment, but chronic recurrences and epiphora are potential sequelae. Patients should be educated that a DCR surgical procedure may be needed to prevent future recurrences in some cases.