Comparative efficacy of macrolides containing marine actinomycetes formulation versus ciprofloxacin ophthalmic solution in controlling Pseudomonas aeruginosa induced conjunctivitis on rabbit model

The main objective of this study was to evaluate the antimicrobial activity and anti-inflammatory activity of marine actinomycetes extract against ocular pathogen Pseudomonas aeruginosa. Actinomycetes isolated from Rameswaram coastal region, Tamilnadu, India were initially screened by primary screening and secondary screening against ocular pathogen P. aeruginosa. Followed by anti-conjunctivitis efficacy of actinomycetes ethyl acetate extract formulation versus ciprofloxacin ophthalmic solution was evaluated using rabbit as animal model. The bioactive compounds present in the best actinomycetes extract was identified by HPTLC and GC–MS analysis. Finally the screened best actinomycetes was identified by 16S rRNA sequencing method. In primary screening 28 actinomycetes that inhibited the growth of P. aeruginosa were taken for secondary screening. In secondary screening RAM24C2 extract had maximum activity against P. aeruginosa. In vivo study of conjunctivitis developed rabbits treated with RAM24C2 extract formulation showed the best clinical cure than ciprofloxacin ophthalmic solution. The RAM24C2 extract was chromatographically characterized and found to contain macrolides. In addition, the effective major pivotal molecule in the extract was detected as 1, 2 benzene dicarboxylic acid and Bis (2-ethylhexyl) phthalate by GC–MS analysis. The RAM24C2 strain was identified as Streptomyces sp. MAD01 and the sequence was submitted in NCBI with accession number JX050218. From our study it is found that the ethyl acetate extract obtained from marine actinomycetes is effective against ocular pathogen P. aeruginosa. Compared to ciprofloxacin ophthalmic solution our RAM24C2 extract formulation hastens the cure of conjunctivitis developed rabbits and need less dosage frequency.