Microbiota and microbiome of the lacrimal drainage system

This review analyzes current concepts of the role of the microbiota and microbiome in the physiology and pathology of the human lacrimal drainage system (LDS). The terms are clearly differentiated: microbiota is the collection of living microorganisms, whereas microbiome also includes their genetic material and habitat. The article describes anatomical features of the LDS and involutional changes in adults (atrophy of the lacrimal puncta, canalicular fibrosis, and nasolacrimal duct stenosis), which predispose to tear stagnation and inflammation. The review includes a comparative analysis of the microbiological spectrum in healthy individuals and patients with dacryocystitis and canaliculitis. The composition of the flora was found to differ substantially depending on age (predominance of S. pneumoniae in children versus Staphylococcus spp. in adults) and geographical region. Metagenomic sequencing data (16S rRNA) demonstrate significantly greater microbial diversity compared with conventional culture methods, revealing a broad spectrum of aerobes, anaerobes, and fungi. The work pays particular attention to regional resistance patterns, including the high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in several Asian countries. Based on the literature data this study proposes and algorithm for empirical antibacterial therapy, taking into account the likely pathogens, as well as the indications for surgical correction, and emphasizes the prospects for creating a national map of the LDS microbiome in the Russian Federation to optimize treatment strategies for dacryocystitis and dacryostenosis.