A total of 108 strains of C jejuni isolated from pigs and chickens were examined for the susceptibility to 10 antimicrobial agents and normal sera of cattle, sheep, guinea pigs and chickens.
Minimal inhibitory concentration(MIC) ranges of antimicrobial agents to C jejuni isolates were◎1.56 to◎100㎍/㎖ for erythromycin, rifampin, streptomycin and tetracycline, 50 to◎100㎍ for cephalothin,◎1.56 to 50g for ampicillin,◎1.56 to 25㎍ for kanamycin and nalidixic acid,◎1.56 to 12.5㎍ for chloramphenicol and gentamicin.
Resistance rates of C jejuni were showed to in order of rifampin(84.7%), tetracycline(56.2 %), erythromycin(17.1%) and ampicillin(3.8%), all of the strains were sensitive to chloram phenicol, gentamicin and kanamycin, and the incidence rates of resistant C jejuni were highly frequent in pig isolates than chicken isolates.
The drug resistance patterns of 87 chicken isolates C jejuni to 9 antimicrobial drugs were showed 12 patterns, and Sm Ra Tc(24.1%), Sm Ra(21.8%) and Ra Tc(14.9%) were relatively common, and also 21 pig isolates were showed 6 patterns and Em Sm Ra Tc(57.1%) were most frequent. The majority of the isolates showed multiple drug resistance.
Bactericidal activity of 10% normal sera from healthy animals were examined for 60min at 37℃.
C jejuni were decreased from 0.4 to 1.0 log_(10)(p<0.01), and serum susceptibility were high in order of guinea pig, sheep, chicken and cattle sera.
Serum sensitivity of C jejuni Ch-39 strain in increased serum concentation up to 10, 20, 40 and 80% were highly significant.
In the normal animal serum, the number of Ch-39 strain were decreased from 1.8×10⁴/㎖ to 2.7×10³/㎖ after 60 min incubation(p<0.01), but the numbers were decreased to 6.6×10³/㎖ in the heat inactivated normal serum for 30 min at 56℃. Bactericidal activity was restored in the heat inactivated normal serum after the serum of complement source was added.
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