The Microbiome of the Nasolacrimal System and Its Role in Nasolacrimal Duct Obstruction.

Acquired nasolacrimal duct obstruction (NLDO) is a common problem leading to epiphora, the pathophysiology of which remains unclear. Culture-based studies have found Staphylococcal species to be the most prevalent organisms, reported in 47% to 73% of patients with NLDO. Recently, culture-independent molecular methods of have allowed more comprehensive detailing of local microbiota. This study aims to evaluate the sinonasal and lacrimal microbiome of patients undergoing dacryocystorhinostomy for NLDO using 16S-amplicon sequencing. Guarded intraoperative swabs were taken from the middle meatus (MM), inferior meatus, and the opened lacrimal sac of 14 NLDO patients undergoing dacryocystorhinostomy and from the inferior meatus and MM on the contralateral unaffected side. MM swabs from 12 control patients were compared with NLDO patients. Comparing microbiota at lacrimal sac to MM and inferior meatus sites reveals that the lacrimal sac microbiome is dominated by Staphylococci (36.3%) and Corynebacterium (35.8%). No significant genus differential abundance between the 3 sites, and between the ipsilateral and contralateral sinonasal swabs, and no convincing evidence of reduced alpha diversity in all comparisons. There was a statistically significant lower relative abundance of Corynebacterium (37.6% vs. 65.1%; p = 0.035) in the MM of NLDO patients compared with controls. The lacrimal sac microbiome in acquired NLDO is similar to the sinonasal microbiome. The relative abundance of Corynebacterium was reduced compared with controls. These findings suggest that an altered sinonasal microbiome may be associated with NLDO, either as a consequence or a risk factor, and merits future research.The authors have demonstrated a decreased relative abundance of Corynebacterium at the middle meatus of patients with ipsilateral nasolacrimal duct obstruction (NLDO), compared with controls, and that the lacrimal sac microbiome is similar to the sinonasal microbiome. An altered microbial state may, therefore, be associated with NLDO, either as a consequence or a risk factor, and merits future research.