ISOLATION AND CHARACTERIZATION OF BACTERIA FROM KERATOCONJUNCTIVITIS AFFECTED CATTLE WITH THEIR PATHOGENICITY AND <i>IN VITRO</i> ANTIBIOTIC SENSITIVITY

Abstract

Isolation and characterization with antibiotic sensitivity of the bacteria in the eye swab of 34 keratoconjunctivitis affected cattle were carried out on the basis of their morphology, staining, cultural and biochemical properties during the period from October 1999 to March 2000. Staphylococcus spp. (76.5%), Streptococcus spp. (38.2%), E. coli (52.9%), Bacillus spp. (70.6%), unidentified Gram positive cocci (5.9%) and unidentified Gram negative rods (20.6%) were identified as a single or mixed infection. Pathogenicity study of these isolated organisms showed conjunctivitis associated with Staphylococcus spp., Streptococcus spp., Bacillus spp. and E. coli in experimentally inoculated mice whereas unidentified Gram positive cocci did not show any conjunctivitis in mice. The mixed intraocular inoculation of these isolated bacteria produced severe keratoconjunctivitis within 24 hours both in mice and calves. Results of antibiotic sensitivity test showed that all types of bacterial isolates were found highly sensitive to oxytetracyclin (80-100%) and chloramphenicol (70-100%). Staphylococcus spp., Streptococcus spp. and Bacillus spp. were moderately susceptible to streptomycin (69.56%), trisulfa (60%) and trisulfa (80%) respectively. It may be concluded that among the tested antibiotics, oxytetracyclin may have the preference in clinical therapy of keratoconjunctivitis in cattle caused by bacteria in Bangladesh.