红霉素耐药葡萄球菌对克林霉素诱导性耐药的研究

Study of Inducible Clindamycin Resistance in Erythromycin Resistance Staphylococcus Isolates

目的：了解临床分离的红霉素耐药葡萄球菌对克林霉素诱导性耐药的发生率，比较双纸片扩散法（D试验）中纸片之间距离对试验结果的影响。方法VITEK-2微生物分析系统检测为红霉素耐药、克林霉素敏感或中介的葡萄球菌135株，其中金黄色葡萄球菌（SA）为55株，凝固酶阴性葡萄球菌（CNS）为80株。比较红霉素纸片与克林霉素纸片边距15 mm与26 mm对结果的影响。结果 D试验阳性率为57.0%，其中SA阳性率70.9%， CNS为47.5%（P＜0.01）。纸片边距15 mm组D试验阳性77株，26 mm组仅69株，漏检率10.4%（P＜0.05）。结论实验室应常规开展D试验，D试验中双纸片间距以15 mm为佳。

Objective To investigate the prevalence of inducible clindamycin resistance in clinical isolates Staphylococcus isolates which resistant to erythromycin and the effect to test results by different disk distance in D-test. Methods A total of 135 strains of Staphylococcus resistant to erythromycin and intermediate or susceptible to clindamycin were collected by VITEK-2 all-automatic microbiology analysis system, including 55 strains of Staphylococcus aureus and 80 strains of coagulase-negative Staphylococcus. Disk distance 15 mm and 26 mm were separately tested, to compare their D-test results. Results The prevalence of inducible clindamycin resistance in erythromycin resistance Staphylococcus isolates was 57.0% in total, 70.9% in Staphylococcus. aureus and 47.5%in coagulase-negative Staphylococcus, P〈0.01. When the distance is 15 mm, D-test picks out 77 strains, when 26 mm, only picking out 69 strains, miss rate 10.4% （P〈0.05）. Conclusion The detection of inducible clindamycin resistance in erythromycin resistance Staphylococcal isolates should be stressed in laboratory. The better distance is 15 mm in D-test.