Microbiome analysis of contact lens care solutions and tear fluids of contact lens wearers: Possible involvement of streptococcal antigens in allergic symptoms related to contact lens wear

Abstract

The present study elucidated the pathogenesis of allergic symptoms (AS) related to contact lens (CL) wear by assaying CL care solutions in lens storage cases and tears from subjects with AS using molecular biology techniques. A total of 15 CL storage cases were collected from subjects with AS (n=9) and healthy, asymptomatic control CL wearers (n=6). Bacterial populations in CL care solutions and tears were assayed by culture and 16S rDNA sequencing. Histamine levels in tears were measured by high‑performance liquid chromatography. Western blot analysis was performed to identify the bacteria recognized by tear IgE from subjects with AS. No significant differences were found in the culture results between the subjects with AS and asymptomatic subjects. Histamine was detected in 2 subjects with AS. Meta‑16S rDNA sequencing identified a cluster of 4 subjects with AS that were distinguished from others by principal coordinate analysis. Detailed population analysis revealed that the abundance of Gram‑positive bacteria in the microbiomes of CL care solutions used by the subjects with AS were higher than those of asymptomatic subjects (42.24±9.47 vs. 16.85±22.76% abundance). Among these, Streptococcus was the dominant genus (12.1‑18.3% abundance). Tear microbiome analysis revealed that the abundance of Streptococcus in the subjects with AS was significantly higher than that in other subjects (19.02±5.50 vs. 3.08±3.35%, P<0.01). Western blot analysis demonstrated that the tear IgE in all subjects with AS reacted with Streptococcus (100%), but not with Staphylococcus. On the whole, these results provide novel insight into the pathogenesis of AS and identify Streptococcus as an important factor in AS associated with CL wear.

Figure 1

Microbiome analysis of contact lens care solutions. (A) PCoA of CL care solutions. Black dots denote healthy subjects, and white dots denote subjects with AS. Three contamination patterns were observed in the CL care solutions of AS subjects by PCoA. (B) Representative bacterial genera with >5% abundance in each CL care solution. CL care solutions of the CL-I group uniquely contained Streptococcus (shown in magenta) as a dominant member of the contaminants. PCoA, principal coordinate analysis; CL, contact lens; AS, allergic symptoms; OTU, operational taxonomic unit; I, CL-I group; II, CL-II group; III, CL-III group. (C) Shannon-Weaver index. The Shannon-Weaver index of the CL-I group is significantly higher than that of the other subjects with AS or healthy subjects. ^*P<0.01.

Figure 2

Microbiome analysis of tear fluids. (A) PCoA of tear fluids. Black dots denote healthy subjects, and white dots denote allergic symptoms (AS) subjects. Tear fluids from AS subjects clearly separated according to the grouping based on the microbiome patterns in contact lens (CL) care solutions. (B) Representative bacterial genera with >5% abundance in each tear fluid. Proportion of Streptococcus in the tear fluid of the CL-I group was significantly higher than in the other subjects. (C) Comparison of the microbial compositions in CL care solutions and tear fluids. White circles denote tear fluids of subjects with AS, black circles denote tear fluids of healthy subjects, white squares denote CL care solutions of subjects with AS, and black squares denote CL care solutions of healthy subjects. The microbiomes in CL care solutions and tear fluids of the CL-I group were clustered closely by PCoA. PCoA, principal coordinate analysis; CL, contact lens; AS, allergic symptoms; OTU, operational taxonomic unit; I, CL-I group; II, CL-II group; III, CL-III group.

Figure 3

Western dot blot hybridization using tear fluids. (A) Arrangement of western dot blot hybridization. The nitrocellulose membrane was divided into 12 sections. Human IgE, positive control; SA, bacterial cell suspension of Staphylococcus (S.) aureus; BHI, brain heart infusion; negative control, StrP sup, culture supernatants of Streptococcus (Str.) pneumoniae; StrT sup, culture supernatants of Str. tigurinus; SC sup, culture supernatants of S. capitis; SE sup, culture supernatants of S. epidermidis; StrP, bacterial cell suspension of Str. pneumoniae; StrT, bacterial cell suspension of Str. tigurinus; SC, bacterial cell suspension of S. capitis; SE, bacterial cell suspension of S. epidermidis. (B) Images of nitrocellulose membrane. IgE binding to bacterial cell suspension of Str. pneumoniae and Str. tigurinus was detected in tear fluids from subjects with allergic symptoms (AS) as well as healthy subjects.