Analysis on testing of quinolone resistance in Laribacter Hongkongensis / 实用医学杂志

ABSTRACT

Objectives To investigate the prevalance of quinolone resistance in Laribacter hongkongensis and to evaluate the influence of agar dilution and disc diffusion methods on susceptibility testing for the bacterium. Methods Susceptibility to quinolones of L.hongkongensis was tested by agar dilution and disc diffusion methods. The results for both methods were compared. Results L.hongkongensis isolates exhibited different susceptibility rate for quinolones (levofloxacin>ciprofloxacin>norfloxacin>nalidixic acid). All of the fish isolates were susceptible to levofloxacin and more than 90%were susceptible to ciprofloxacin and Norfloxacin. However,by agar dilution, only 62.50%, 37.50%,48.21%, 19.64%of the frogs isolates were susceptible to levofloxacin, norfloxacin, ciprofloxacin, nalidixic acid, respectively. For fish isolates, comparision of susceptibilities between agar dilution and disc diffusion showed a high (> 95%) percentage agreement for levofloxacin and ciprofloxacin and the highest crepancies were observed with norfloxacin (100%) .But it showed a high discrepancy when comparing the two methods for frogs isolates. Conclusions The resistance rate of L. hongkongens to quinolones was high , especially for frog isolates. The results suggested the use of agar dilution on susceptibility testing for quinolones in L. hongkongensis.