Antimicrobial Susceptibility of Gram-Negative Bacilli Isolated from Bovine Udder Infections

젖소 유방염유래(乳房炎由來) Gram 음성간균의(陰性桿菌) 약제감수성(藥劑感受性)

Antimicrobial susceptibility of 157 Gram-negative bacilli (90 Escherichia coli. 30 Enterobacter aerogenes, 18 Klebsiella pneumoniae, 12 Proteus spp., 3 Pseudomonas aeruginosa and 4 Alcaligenes faecalis) isolated from infected bovine udders was determined by the plate dilution method. Gentamicin and oxolinic acid at a concentration of $12.5{\mu}g/ml$ were very active to all of 157 Gram-negative bacilli tested, and 98% of these strains were susceptible to nalidixic acid at a concentration of $25{\mu}g/ml$. Most of the 90 Escherichia coli strains were inhibited by chloramphenicol, ampicillin and carbenicillin and carbenicillin at a concentration of $12.5{\mu}g/ml$. None of the Klebsiella pneumoniae strains were inhibited at a concentration of $50{\mu}g/ml$ of ampicillin and carbenillin, whereas all the species of Proteus resisted a concentration of $50{\mu}g/ml$ or higher tetracycline. All the 3 strains of Pseudomonas aeruginosa were highly resistant to streptomycin, kanamycin, Ampicillin, chloramphenicol, tetracycline and nalidixic acid.