<prompt> The most common causative organism of canaliculitis isHSVCandida albicansActinomyces israeliiNocardia asteroides  <response>: Chronic canaliculitis is an uncommon condition, frequently caused by Actinomyces israelii, anaerobic Gram-positive bacteria. Occasionally scarring and canalicular obstruction may result. Presentation is with unilateral epiphora associated with chronic mucopurulent conjunctivitis refractory to conventional treatment. There is pericanalicular redness and oedema, and mucopurulent discharge on pressure over the canaliculus. A pouting punctum may be a diagnostic clue in mild cases. In contrast to dacryocystitis, there is no lacrimal sac involvement. Concretions sulfur granules are metabolic products of Actinomyces and other hydrogen sulfide-utilizing bacteria, and classically are expressed on canalicular compression or following canaliculotomy 