The Species Composition of Microbiota and Biological Properties of Dominant Bacterial Species in the Lacrimal Fluid in Patients with Endogenous Uveites

Abstract

The purpose: to study the species composition of the lacrimal fluid microbiota in patients with endogenous uveitis and the biological properties of dominant species of bacteria.Patients and Methods. A bacteriological study of the lacrimal fluid of 107 patients (114 eyes) with endogenous uveitis and 28 practically healthy persons (control) was carried out. The research was performed using the conventional methods. The isolated microorganisms were identified up to the species. We studied the main biological properties of bacteria — the presence of persistence and virulence factors of isolated dominant species.The results. 43 strains of various types of bacteria were isolated from the lacrimal fluid of patients with uveitis, bacteria of the genus Staphylococcus prevailed, S. aureus was isolated in 23.3 % of cases, and the remaining strains were representatives of coagulase-negative staphylococci. The species composition of the bacteria isolated from practically healthy individuals did not differ in essence. Isolated strains of S. aureus had a significant set of virulence factors. All isolates lysed sheep red blood cells, 80 % of the cultures had lecithovitellase and 60 % — DNA-se activity. Representatives of coagulase-negative staphylococci were characterized only by hemolytic activity. In the study of persistence factors, it was found that all the studied strains of S. aureus and the vast majority of representatives of coagulase-negative staphylococci isolated from tears were resistant to lysozyme. Biofilm formation was more typical for S. aureus strains 90 % versus 34.4 % for representatives of coagulase-negative staphylococci (t = 2.194, p = 0.034). Similar patterns were found in relation to complement resistance, 90 % of S. aureus cultures and 37.5 % of coagulase-negative staphylococci (t = 2.055; p = 0.046).Conclusion. Among the microorganisms isolated from the lacrimal fluid, Staphylococcus bacteria prevailed, from which S. cohnii was most often isolated. S. aureus to a greater extent than coagulase-negative staphylococci had a certain set of virulence and persistence factors. The microbiocenosis of the lacrimal fluid of patients with endogenous uveitis did not differ from practically healthy individuals. The presence of S. aureus in lacrimal fluid is a risk factor for the development of endogenous uveitis in cases of chronic oral and ENT organ diseases.

Keywords

• endogenous uveitis
• lacrimal fluid
• microbiota
• dominant bacterial species