Genetic Characterization and Biofilm-Forming Capacity of Bacterial Population Isolated from Conjunctival Samples

Area of Science:

• Ophthalmology
• Microbiology
• Infectious Diseases

Background:

• Bacterial conjunctivitis is a common ocular infection.
• Multidrug-resistant (MDR) isolates pose a significant clinical challenge.
• Ocular infections can impact perioperative outcomes, especially in vulnerable populations.

Purpose of the Study:

• To characterize conjunctival bacterial isolates phenotypically and genotypically.
• To evaluate the biofilm-forming capacity of these isolates.
• To investigate the relationship between antimicrobial resistance (AMR) genes, resistance phenotypes, and biofilm-associated AMR.

Main Methods:

• Prospective, single-center, cross-sectional study of conjunctival bacterial isolates.
• Antimicrobial susceptibility testing (AST) and quantitative PCR for resistance genes.
• Microtiter plate assay for biofilm formation and biofilm susceptibility assays for amikacin (AK) and levofloxacin (LEV).

Main Results:

• Prevalence of Gram-positive cocci (84.6%), with 65.2% being multidrug-resistant, particularly *Staphylococcus epidermidis*.
• Strong biofilm formation observed in 58.3% of Gram-negative bacilli versus 22.7% of Gram-positive cocci.
• Biofilm-embedded bacteria exhibited increased tolerance to AK and LEV, especially in *S. aureus* and *S. epidermidis*.

Conclusions:

• The study highlights the clinical significance of biofilm-related resistance in bacterial conjunctivitis.
• Integrating AMR profiling with biofilm assessment is recommended for optimizing empirical therapy.
• Findings underscore the need for targeted treatment strategies against MDR conjunctival isolates.