Polybacterial community analysis in human conjunctiva through 16S rRNA gene libraries

Area of Science:

• Ophthalmology
• Microbiology
• Genetics

Background:

• The human conjunctival sac hosts diverse microorganisms.
• Bacterial ocular infections can arise from compromised eye barriers.
• Current microbiological methods for conjunctival swabs often yield unsatisfactory results.

Purpose of the Study:

• To identify the bacterial community in the human conjunctiva of pre-operative subjects using 16S rRNA gene libraries.
• To investigate the limitations of traditional culture-based methods in detecting conjunctival bacteria.

Main Methods:

• Collected 45 conjunctival swab samples from pre-operative cataract surgery patients.
• Constructed 36 bacterial nested-PCR-positive 16S rRNA gene libraries.
• Utilized Amplified Ribosomal DNA Restriction Analysis (ARDRA) for clone screening.
• Sequenced representative clones for phylogenetic analysis.

Main Results:

• Identified a polybacterial community across Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes, and Deinococcus-Thermus phyla.
• Detected diverse bacterial species, including 17 novel species not previously reported in ocular infections.
• Sequencing data suggested the presence of 6 unidentified bacteria, potentially novel organisms.
• Revealed polybacterial presence where culture methods identified no or single bacteria.

Conclusions:

• The human conjunctiva harbors a complex, polybacterial community, often missed by traditional methods.
• Broad-spectrum antibiotic therapy is recommended for pre-operative cataract surgery patients due to identified polybacterial infections.
• Further research is needed to understand conjunctival microbial communities for improved antibiotic strategies and diagnostic probe development.