耐碳青霉烯类弗氏柠檬酸杆菌的表型及基因型特征研究  

Phenotypes and genotypes of carbapenem-resistant Citrobacter freundii

作　　者：薛武进[1] 揭伟霞[1] 李凌云[1] 刘伍高 

机构地区：[1]丽水市人民医院检验科,浙江丽水323000

出　　处：《中华医院感染学杂志》2013年第24期5908-5910,共3页Chinese Journal of Nosocomiology

基　　金：浙江省自然科学基金项目(LY12H19003)

摘　　要：目的分析耐碳青霉烯类弗氏柠檬酸杆菌的表型和基因型特征,为临床资料提供参考依据。方法收集2008年1月-2011年12月临床分离的18株非重复耐碳青霉烯类弗氏柠檬酸杆菌;采用琼脂稀释法检测弗氏柠檬酸杆菌对抗菌药物的敏感性;PCR扩增检测β-内酰胺酶基因;质粒转移接合试验检测耐药β-内酰胺酶耐药基因的可传递性。结果替加环素、米诺环素和多西环素对耐碳青霉烯类弗氏柠檬酸杆菌有较好的抗菌活性,MIC50值分别为1、4、4μg/ml,MIC90值分别1、8、4μg/ml,弗氏柠檬酸杆菌对常用抗菌药物表现为高度耐药,MIC90多数≥128μg/ml;PCR检测结果显示,所有菌株均产生KPC-2型基因碳青霉烯酶;除一株细菌产CTX-M-15型基因ESBLs外,其余菌株均产CTX-M-14型基因ESBLs;所有菌株均产CMY-2型基因质粒AmpC酶;质粒转移接合试验结果表明,携带KPC-2型基因碳青霉烯酶耐药基因的质粒可从供体菌转移至敏感细胞中。结论临床分离的耐碳青霉烯类弗氏柠檬酸杆菌呈泛耐药特征,使临床抗感染治疗的难度增大,临床应注意预防控制此类耐药菌株引起的进一步流行传播。OBJECTIVE To explore the phenotypes and genotypes of the carbapenem-resistant Citrobacter freundii so as to provide bases for clinical data. METHODS Totally 18 strains of non-repetitive carbapenem-resistant C. freundii isolated from Jan 2008 to Dec 2011 were collected, then the drug susceptibility of the C. freundii was tested with the use of agar diffusion method, the β-lactamase genes were amplified and detected by using PCR, and the transfer and conjugation trial of plasmid was performed for the test of transitivity of β-lactamase resistance genes. RESULTS The tigecycline, minocycline, and doxycycline had high antibacterial activity against carbapenemresistant C. freundii, the MICro values were 1, 4, and 4, and MICg0 ualues were 1, 8, and 4, respectivele μg/ ml. The C. freundii strains were highly resistant to the commonly used antibiotics, with the MICg0 value no less than 128 μg/ml. The result of PCR test showed that all the strains have produced KPC-2-type carbapenemase; all the strains have produced the CTX-M-14-type ESBLs except for one strain that has produced CTX M-15-type ESBLs. All the strains have produced CMY-2-type AmpC enzyme. The result of transfer and conjugation trial for the plasmids indicated that the plasmids carrying the KPC-2 type carbapenemase resistance genes could transfer from the donor strains to the susceptible cells of recipients. CONCLUSION The clinical isolates of carbapenem- resistant C. freundii show pandrug-resistance, which makes the clinical anti-infection therapy more difficult; it is necessary for the hospital to attach importance to the further spread of such drug resistant strains.

关 键 词：药物敏感性试验 碳青霉烯类 弗氏柠檬酸杆菌 泛耐药 

分 类 号：R378[医药卫生—病原生物学]