摘要
目的了解湘雅医院临床分离凝固酶阴性葡萄球菌(CNS)药物敏感性,初步探讨细菌生物膜的耐药机制及黏质物在其中的作用。方法临床分离的158株CNS,纸片扩散法检测其对抗菌药物的敏感性;比色法测定其黏质物量;提取黏质物并以聚丙烯酰胺凝胶电泳分析;微量肉汤稀释法测定提取的黏质物对万古霉素、庆大霉素、利福平最小抑菌浓度(MIC)的影响。结果CNS对青霉素、红霉素、复方新诺明的耐药率高,对氨苄西林/舒巴坦和利福平较敏感,未发现耐万古霉素的菌株;158株CNS除1株外均产黏质物,高/低产黏质物组菌株的产黏质物量差异有统计学意义(P<0.05),而纸片扩散法测定的耐药率P>0.05;20 mg/ml的黏质物可增加万古霉素、庆大霉素MIC,对利福平无影响;提取的黏质物为糖胺聚糖,其与硫酸软骨素的迁移率相近。结论CNS在一定条件下普遍产黏质物,进而形成生物膜,黏质物可因分子筛效应或干扰抗菌药物活性而增加万古霉素、庆大霉素的MIC,致使含生物膜的CNS耐药性增高。
OBJECTIVE To evaluate the antibiotic susceptibility on coagulase negative staphylococci （CNS） in Xiangya Hospital and to investigate the role of slime in the resistance mechanism of biofilms. METHODS To isolate and identify CNS from clinical specimens. The susceptibility of 15 antibiotics was tested by the disc diffusion method. The quantity of slime produced by CNS was measured by the colorimetric method. Slime was isolated from selected strains of CNS and analyzed by SDS-PAGE. The MICs to vancomycin, gentamicin and rifampin were determined with and without the addition of extracted slime by a standard microtiter method. RESULTS Of all these 15 antibiotics, the highest resistance to CNS was penicillin, followed by erythromycin and trimethoprim-sulfamethoxazole. CNS was more susceptible to ampicillin/sulbactam and rifampin. None was resistant to vancomycin. All of 158 CNS, except one strain, could produce slime. There was a statistical difference between the quantities of slime produced by CNS that produced high and low quantity slime. However, there was a non-statistical difference of resistance to these 15 antibiotics of above CNS. There was an increase in the MICs to vancomycin and gentamicin, but no in the MIC to rifampin, in the absence of 20mg/ml extracted slime. The extracted slime seemed to be similar to the glycosaminoglycans （GAG） ; it had mobility similar to that of chondroitin sulfate. CONCLUSIONS CNS can produce slime on some condition, universally, then to form biofilms. However, in vitro susceptibility testing employed cannot really reflect the susceptibility of bacteria in biofilms in vivo. Slime can increase the MICs to vancomycin and gentamicin because of interference with either the antimicrobial action of these drugs or the perfusion of these drugs through the medium to increase the resistance of biofilms. It does not affect the MIC to rifampin.
出处
《中华医院感染学杂志》
CAS
CSCD
北大核心
2006年第10期1089-1092,共4页
Chinese Journal of Nosocomiology
关键词
凝固酶阴性葡萄球菌
药物敏感性
生物膜
黏质物
耐药机制
Coagulase-negative staphylococci
Antibiotic susceptibility
Biofilm
Slime
Resistance mechanism
