Evaluation and modulation of bactericidal potential of different antibacterial agents against bacterial pathogens...

Conjunctivitis is one of the most common eye infections seen in hospitals. Youngsters under the age of seven, women at age 22 and men at age 28 are most likely to be diagnosed with this infection. The current study was designed to identify and characterize the conjunctivitis associated pathogens and to evaluate their sensitivity or resistance against commonly used antibiotics (metronidazole, ciprofloxacin, azithromycin, and levofloxacin), aqueous plant extracts (Ficus religiosa, Syzygium cumini, Azadirachta indica, Allium cepa, Eucalyptus camaldulensis, Syzygium aromaticum, Aloe barbadensis, and Citrus limon) and green synthesized silver nanoparticles. The samples were taken at Fatima Memorial Hospital, Lahore. Blood agar test was used for screening of alpha and beta hemolytic bacterial pathogens. Antibacterial activity against pathogenic isolates was done using well diffusion method. Antibiotics showed range of bactericidal potential against pathogens considerably more effective against isolated bacteria. Maximum antibacterial activity against bacterial strains was observed in E. camaldulensis, S. cumini, and C. limon (13.66 ± 1.20 to 9 ± 0.57, 15.5 ± 0.76 to 10.33 ± 1.45, and 21.33 ± 0.88 to 12.66 ± 0.33 respectively). Green synthesized silver nanoparticles showed better results as antibacterial agents with the zones of inhibition measuring 11.66 ± 0.66 to 8.83 ± 0.72; 12.5 ± 0.62 to 9.83 ± 0.72; 16.16 ± 1.09 to 10.83 ± 1.01; 13.33 ± 1.20 to 8.83 ± 0.72; 12.16 ± 1.16 to 7.33 ± 0.66, and 13.16 ± 0.59 to 8.33 ± 0.88 respectively. Biochemical and molecular characterization of pathogens was done. Bacterial strains were identified as Bacillus thuringiensis, Bacillus cereus, Bacillus paramycoides, Bacillus coahuilensis and Pseudomonas aeruginosa. This study showed that because of mis- use or over use of antibiotics, pathogens have developed resistance. So conventional medication may be replaced by biological antibacterial tools such as plant extracts and green synthesized silver nanoparticle.