内蒙古乌兰察布地区布鲁氏菌体外药物敏感性及耐药机制分析

目的调查内蒙古乌兰察布地区分离布鲁氏菌的抗生素药物敏感(耐受)性特征。方法采用E-test法测定了85株布鲁氏菌对13种临床常用药物的敏感性;同时,对利福平和阿奇霉素的耐药机制进行了初步探讨;并采用K-B法对来自全国的149株羊种布鲁氏菌对复方新诺明和利福平的敏感性进行了筛查。结果试验表明布鲁氏菌对阿奇霉素、复方新诺明和利福平耐药菌株数分别为100%(85/85),7.0%(6/85)和1.0%(1/85)。所有菌株对司帕沙星、米诺环素、多西环素、四环素、链霉素、庆大霉素、左氧氟沙星、环丙沙星、头孢吡肟及头孢哌酮舒巴坦均表现为敏感;司帕沙星、米诺环素的MIC₉₀值(0.032μg/mL)最低。所有阿奇霉素耐药菌株的23S rRNA基因的第2632位碱基表现为T→C单位点突变,布鲁氏菌23S rRNA转肽酶中心的T/C点突变可能是一种羊种布鲁氏菌对阿奇霉素耐药的分子机制。K-B法筛查结果表明所有菌株对利福平敏感,25.5%(38/149)的菌株对复方新诺明耐药,耐药菌株分布于18个省市区。结论乌兰察布地区羊种布鲁氏菌耐药较为严重,应定期进行药物敏感性监测。推荐司帕沙星和米诺环素作为一线布病治疗药物。

In vitro drugs susceptibility and resistance mechanism investigation of Brucella isolates from Ulanqab region of Inner Mongolia

The aims of this study is to investigate the antibiotics susceptibilities profiles of Brucella strains obtained from Ulanqab of Inner Mongolia. The susceptibilities of 85 B.melitensis strains to 13 common used antibiotics was detected by E-test method, and resistance mechanism of rifampin and azithromycin were preliminarily examined. Subsequently, susceptibility of 149 B. melitensis strains from China to cotrimoxazole and rifampin were tested using K-B method. The study found that the number of strains resistance to azithromycin, cotrimoxazole and rifampin was 100% (85/85),7.0% (6/85) and 1.0% (1/85), respectively. All of the tested isolates were susceptible to minocycline, sparfloxacin, doxycycline, tetracycline, streptomycin, gentamicin, levofloxacin, ciprofloxacin, cefotaxime and cefoperazone sulbactam. Of them, aparfloxacin and minocycline shows the lowest MIC₉₀ value (0.032 μg/mL). The polymorphism of 2632 base T/C in the 23S rRNA of Brucella spp. was a potential molecular mechanism of B. melitensis in this study resistant to azithromycin. K-B method screen data indicated that all of 149 strains were susceptible to rifampin. Moreover, 25.5% (38/149) of strains were resistance to cotrimoxazole and these resistance strains were distributed in 18 different provinces of China. In conclusion, the situation of antibiotics resistance of B. melitensis clinical isolates was rather serious in Ulanqab region, surveillance of changes in antibiotic susceptible should be regular implemented. Moreover, we suggest that both minocycline and sparfloxacin could be as first-line agents for treatment of brucellosis.