Hunfeld K P, Kraiczy P, Wichelhaus T A, Schäfer V, Brade V
Institute of Medical Microbiology, University Hospital of Frankfurt, Frankfurt/Main, Germany.
Eur J Clin Microbiol Infect Dis. 2000 Jan;19(1):27-32. doi: 10.1007/s100960050005.
A newly developed colorimetric microdilution method was used to analyze the activity of 12 antimicrobial agents against nine Borrelia burgdorferi isolates, including all three genospecies pathogenic for humans. In addition, in vitro antimicrobial resistance patterns of Borrelia valaisiana and Borrelia bissettii tick isolates were investigated. The applied test system is based upon color changes that occur in the presence of phenol red and result from the accumulation of nonvolatile acid produced by actively metabolizing spirochetes. After 72 h of incubation, minimal inhibitory concentrations (MICs) were determined from the decrease of absorbance by software-assisted calculation of growth curves. MIC values were lowest for azlocillin (MIC, < or = 0.125 microg/ml), ceftriaxone (MIC range, < or = 0.015-0.06 microg/ ml), and azithromycin (MIC range, < or = 0.015-0.06 microg/ml). Whereas tobramycin (MIC range, 8-64 microg/ml) exhibited little activity, spectinomycin (MIC range, 0.25-2 microg/ml) showed in vitro antimicrobial activity against Borrelia burgdorferi. The MICs of penicillin G for Borrelia afzelii isolates were ten times higher than those for Borrelia burgdorferi, Borrelia valaisiana, and Borrelia bissettii isolates (P<0.05) and 100 times higher than those for isolates belonging to the genospecies Borrelia garinii (P < 0.05). Further significant differences with respect to the MIC values of the other antimicrobial agents tested were not noted. The colorimetric microdilution method offered the advantages of reliability, reproducibility, and convenience and could handle large numbers of isolates and antibiotics.
一种新开发的比色微量稀释法被用于分析12种抗菌剂对9株伯氏疏螺旋体分离株的活性，其中包括对人类致病的所有三种基因型。此外，还研究了瑞士疏螺旋体和比氏疏螺旋体蜱分离株的体外抗菌耐药模式。所应用的测试系统基于在酚红存在下发生的颜色变化，这种变化是由活跃代谢的螺旋体产生的非挥发性酸的积累引起的。孵育72小时后，通过软件辅助计算生长曲线，根据吸光度的降低来确定最低抑菌浓度（MIC）。阿洛西林的MIC值最低（MIC，≤0.125微克/毫升），头孢曲松的MIC范围为≤0.015 - 0.06微克/毫升，阿奇霉素的MIC范围为≤0.015 - 0.06微克/毫升。而妥布霉素（MIC范围为8 - 64微克/毫升）活性很小，壮观霉素（MIC范围为0.25 - 2微克/毫升）显示出对伯氏疏螺旋体的体外抗菌活性。青霉素G对阿氏疏螺旋体分离株的MIC值比对伯氏疏螺旋体、瑞士疏螺旋体和比氏疏螺旋体分离株高10倍（P<0.05），比对伽氏疏螺旋体基因型分离株高100倍（P < 0.05）。未发现与所测试的其他抗菌剂的MIC值有进一步的显著差异。比色微量稀释法具有可靠性、可重复性和便利性的优点，并且可以处理大量的分离株和抗生素。
