19株诺卡菌的药敏与克拉霉素及四环素类耐药相关基因的关系研究

目的 研究诺卡菌临床分离株的药敏及与克拉霉素和四环素类耐药相关基因的关系。方法 以微量肉汤稀释法检测诺卡菌对15种抗菌药物的耐药性；以PCR法检测19株诺卡菌克拉霉素的耐药相关基因ermA、ermB、mefA、msrD，对四环素类的耐药相关基因tetO、tetM、tetL。结果 19株诺卡菌中，ermA基因检出率为15.8%(3/19)，未检出tetO、tetM、tetL、ermB、mefA、msrD基因。药敏结果显示19株诺卡菌对米诺环素和多西环素耐药率均为5.3%，未见克拉霉素耐药菌株。耐药率最高的为环丙沙星，占78.9%，其次为庆大霉素和头孢吡肟，分别占21.1%和15.8%。对其余药物均具有较高的敏感性。结论 诺卡菌对米诺环素、多西环素耐药与tetO、tetM、tetL基因无关，存在另外的四环素类相关耐药机制。ermA基因并不能引起克拉霉素耐药。

Study of relationship between drug susceptibility and related resistant genes of clarithromycin and tetracycline in 19 isolates of Nocardia#br#

Objective To investigate the drug susceptibility and the relationship with related resistant genes of clarithromycin and tetracycline carried in the clinical isolates of Nocardia. Methods Antibiotic susceptibility was determined by broth microdilution method for 15 Nocardia isolates. PCR was used to detect the clarithromycin resistance genes ermA, ermB, mefA and msrD, tetracycline resistance genes tetO, tetM and tetL. Results Of the 19 Nocardia isolates, the detection rate of the gene of ermA was 15.8% (3/19). The genes of tetO, tetM, tetL, ermB, mefA and msrD were not found. The drug resistance rates of 19 isolates of Nocardia to minocycline and doxycycline were both 5.3%, all the isolates were sensitive to clarithromycin. Ciprofloxacin has the highest drug sensitive rates which was 78.9%. The drug sensitive rates of Nocardia to gentamicin and cefepime were 21.1% and 15.8% separately.The drug sensitive rates to others drugs are high. Conclusions The genes of tetO、tetM and tetL do not contribute to the drug resistant mechanisms of minocycline and doxycycline for Nocardia, and may have other resistant mechanisms. The gene of ermA may play any role in resistance of