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目的了解分离于ICU的大肠埃希菌(ECO)氨基糖苷类药物各种耐药相关基因存在状况,探讨ECO多药耐药机制。方法收集2007年12月-2008年6月20株分离自医院ICU患者临床标本的ECO,采用纸片扩散法测定30种抗菌药物的敏感性;采用PCR法检测armA、rmtB、npmA、aac(3)-Ⅰ、aac(3)-Ⅱ、aac(6′)-Ⅰb、aac(6′)-Ⅱ、ant(3″)-Ⅰ、ant(2″)-Ⅰ、ant(4′)-Ⅰa/b、aadA4/5、aadA6/16、aph(3′)-Ⅰ、aph(3′)-Ⅱb、aph(3′)-Ⅵa、3种16S rRNA甲基化酶与12种氨基糖苷类修饰酶基因。结果20株ECO中检出aac(3)-Ⅱ8株(40%)、aac(6′)-Ⅰb 3株(15%)、ant(3″)-Ⅰ3株(15%)、aph(3′)-Ⅰ1株(10%)a、adA4/5 13株(65%)5种氨基糖苷类修饰酶基因,未检出16S rRNA甲基化酶基因;在ECO中发现aadA4/5和aph(3′)-Ⅰ型氨基糖苷类修饰酶基因均为国内首次。结论ECO对氨基糖苷类药物耐药情况严重、机制复杂,产氨基糖苷类修饰酶为主要原因之一。
Objective To understand the existence of various resistance-related genes of aminoglycosides of Escherichia coli (ECO) isolated in ICU and explore the mechanism of ECO multidrug resistance. Methods The ECO of 20 clinical isolates from hospital ICU patients collected from December 2007 to June 2008 were collected and the susceptibilities of 30 antibacterial drugs were determined by disk diffusion method. The expression levels of armA, rmtB, npmA, aac (3) Ant (2 “) - Ⅰ, ant (4 ’) - Ⅰa, aac (6) - Ⅰ b, aac (6’) - Ⅱ, ant a bA, aadA4 / 5, aadA6 / 16, aph (3 ’) - Ⅰ, aph (3’) - Ⅱb and aph (3 ’) - Ⅵa, three kinds of 16S rRNA methylase and 12 kinds of aminoglycoside Enzyme gene. Results AAC (3) -Ⅱ8 (40%), aac (6 ’) - Ⅰb 3 (15%), ant (3 ”) - Ⅰ3 (15%), aph (3’ ), 5 a-aminoglycoside-modifying enzyme genes were not detected in 13 (65%) of adA4 / 5 strains, and 16 ars of aphA4 / 5 and aph ’) -Ⅰ-aminoglycoside modified enzyme were the first in China.Conclusion The drug resistance of aminoglycosides to ECO is serious and its mechanism is complex. One of the main reasons for producing aminoglycoside-modifying enzymes is ECO.