Molecular Confirmation of Moraxella Bovis Associated Infectious Keratoconjunctivitis in Ruminants

Background: Infectious keratoconjunctivitis is a significant problem causing a greater level of economic losses in production animals. The affected animals show progressive cloudiness of eye, severe congestion of ocular mucous membrane with inflammation of cornea, ocular discharges vary from serous to purulent and causes temporary or permanent blindness in affected animals. Methods: A total number of 238 conjunctival swabs were collected from the suspected cases (93 sheep, 98 goats and 47 cattle) of different age groups in both symptomatic and asymptomatic animals during the period of 2021-2023 (both winter and summer season in livestock farms of Tamil Nadu, SBRS –Ooty, PGRIS-Katuakkam, Tirvananamalai, Sheep Research Station-Potaneri, Tiruvallur district). The samples were subjected to bacterial isolation and identification. The bacterial organism isolated from the swabs were characterized by cultural, biochemical and molecular tests. Result: The Moraxella species was successfully isolated from 9 animals (N=5 in cattle and N=4 in sheep). In addition to this Staphylococcus and Klebsiella, (N=34), Streptococcus (N=10), Pseudomonas (N=8) and concurrent infection of Tricophyton verrocosum, Aspergillus. The genomic DNA was extracted from positive culture of morexalla and PCR amplification was performed with specific primers. The amplified PCR product were subjected to partial gene sequencing which showed 99% homology with other, Morexalla bovis isolates. Antimicrobial sensitivity test of the isolates revealed that Moraxella was sensitive towards Chloramphenicol (100%), Ciprofloxacin (100%), Gentamicin (100%), Tylosin (100%) and sensitive to Oxytetracycline (80%), Endrofloxacin (80%), Gatifloxacin (80%) and Metronidazole (70%). All tested isolates were resistant to Norfloxacin, Vancomycin, Ampicillin /Sulbactam, Methicillin and Sulphadiazine.