摘要
目的了解红霉素异质性耐药金黄色葡萄球菌对红霉素和克林霉素的耐药表型和基因型，比较实验室检测方法，以准确报告检测结果，指导临床合理使用抗生素。方法对临床分离的自动化仪器法检测为红霉素敏感的金黄色葡萄球菌，用纸片扩散法进行红霉素药敏试验，筛选出其中耐药的菌株为红霉素异质性菌株。采用纸片扩散法（标准D试验）与自动化仪器法分别检测红霉素异质性耐药菌株对红霉素和克林霉素的耐药表型，比较两种检测方法，并采用连续传代50代的方法验证异质性耐药表型和基因型的遗传稳定性；通过多重PCR检测耐药基因ermA、ermC和msrA。结果95株仪器检测红霉素敏感菌株中，纸片扩散法检测有异质性耐药现象的有70株，占73．7％。仪器法检测异质性耐药金黄色葡萄球菌母代菌株，70株母代菌均对红霉素敏感[最小抑菌浓度（MIC）≤0．25“g／m1]；直接用母代菌株进行D试验，结果不易观察。仪器法检测异质性耐药子代菌株，70株子代菌株均对红霉素耐药（MIC〉8斗∥m1）、对克林霉素敏感（MIC≤0．25μg／m1），对红霉素＋克林霉素耐药，提示红霉素诱导克林霉素耐药试验阳性；70株子代菌株D试验均阳性。对70株异质性耐药母代菌株的初代和50代传代菌株的药敏试验结果显示，红霉素纸片抑菌圈内均有异质性耐药菌株出现，遗传稳定。多重PCR检测结果显示，对红霉素呈异质性耐药的金黄色葡萄球菌菌株包括母代和子代菌株以及经50代传代菌株ermA基因均呈阳性，未检出ermC和msrA基因。结论金黄色葡萄球菌对红霉素的异质性耐药表型和基因型的遗传性稳定，仪器法检测异质性耐药菌株可造成漏检将会影响红霉素和克林霉素在临床上的正确使用，微生物实验室技术人员应该将仪器法检测红霉素敏感的菌株用纸片扩散法进行鉴别。
Objective To explore the phenotypes and genotypes of Staphylococcus aureus （S. aureus） hetero-resistant to erythromycin and clindamyein and compare their detection methods so as to report resuhs accurately to guide clinical rational use of antibiotics. Methods D test was used to detect the phenotypes of S. aureus hetero-resistant to erythromycin. And then the results of two methods （ automated instrument and disk diffusion） were analyzed. All strains were continuously passaged for 50 generations to verify the phenotypic and genotypic stability of hetero-resistance. ErmA, ermC and msrA genes were amplified by multiplex polymerase chain reaction （PCR） . Results Among 95 erythromycin-sensitive strains, there were 70 strains hereto-resistant to erythromyein （73.7%）. The primary 70 strains were all susceptive to erythromycin（ MIC ~〈0. 25 p,g/ml） and clindamyein （ MIC ~〈0. 25 p^g/ml） with the cards of GP- 67 of VITEK2 Compact. With D tests, the results were difficult to observe. The passaged 70 strains were all resistant to erythromyein（ MIC 〉 8 p,g/ml） and susceptible to clindamyein（ MIC ~〈0. 25 p,g/ml） and D test positive with the cards of GP-67 of VITEK2 Compact. The primary and 50th generation of herero-erythromycin resistant strains were stable in susceptibility test results. The primary and the 50th generation strains were all ermA gene positive, ermC and msrA negative with PCR results. Conclusions The phenotypes and genotypes of hetreo-erythromycin resistant S. aureus strains were stable. Missed detection with VITEK2 Compact may affect the proper use of erythromycin and clindamycin. Laboratory technicians should identify the erythromycin-susceptible strains by disk diffusion method.
出处
《中华医学杂志》
CAS
CSCD
北大核心
2013年第48期3867-3871,共5页
National Medical Journal of China
基金
首都医学发展科研基金（2009-3016）
