Drug resistance of Yersinia pestis in natural foci of plague in Inner Mongolia Autonomous Region / 中华地方病学杂志

ABSTRACT

Objective:To investigate the drug resistance of Yersinia pestis to 11 kinds of antibiotics in the natural foci of plague in Inner Mongolia Autonomous Region, and to provide a theoretical basis for scientifically and effectively selecting antibiotics for treatment of the plague. Methods:A total of 137 strains of Yersinia pestis isolated from the natural foci of plague in Inner Mongolia Autonomous Region at different times, regions, hosts and vectors were collected. According to Clinical and Laboratory Standard Institute (CLSI), the agar plate dilution method was used to determine the minimum inhibitory concentration (MIC) of the 11 kinds of antibiotics against 137 strains of Yersinia pestis, including ofloxacin, ciprofloxacin, kanamycin, streptomycin, ceftriaxone, ampicillin, chloramphenicol, spectinomycin, cefuroxime, tetracycline and sulfamethoxazole-trimethoprim. The MIC 50 and MIC 90 (the minimum concentration of drug which could inhibit 50% and 90% of bacterial growth) were calculated, and their sensitivity was determined according to CLSI standards. Results:Among 137 strains of Yersinia pestis tested, no strains of Yersinia pestis had single or multiple resistance to ofloxacin, ciprofloxacin, kanamycin, streptomycin, ceftriaxone, ampicillin, chloramphenicol, spectinomycin, cefuroxime, tetracycline and sulfamethoxazole-trimethoprim. According to CLSI standards, 137 strains of Yersinia pestis were all sensitive to the 11 kinds of antibiotics; among them, ofloxacin, ciprofloxacin, ceftriaxone and sulfamethoxazole-trimethoprim had higher antibacterial activity, with MIC 90 < 0.250 μg/ ml; the antibacterial activity of spectinomycin was the lowest, with MIC 90 of 16.000 μg/ml. Conclusions:The Yersinia pestis isolated from the natural foci of plague in Inner Mongolia Autonomous Region is not found to have single or multiple resistance to the 11 kinds of antibiotics. Continuous drug resistance monitoring of Yersinia pestis should be carried out to provide a basis for clinical medication.