88株嗜麦芽窄食单孢菌氨基糖苷类耐药性及其修饰酶基因分析

目的明确2005年8月至2007年7月临床分离的88株嗜麦芽窄食单孢菌对氨基糖苷类抗生素的耐药性及其修饰酶基因的存在状况。方法用Kirby—Bauer（K-B）药敏试验分析88株嗜麦芽窄食单孢菌对3种常用氨基糖苷类抗生素阿米卡星、庆大霉素、妥布霉素的敏感性，再用聚合酶链反应（PeR）法分别扩增常见的8种氨基糖苷修饰酶基因。结果这88株嗜麦芽窄食单孢菌同时对3种氨基糖苷类抗生素都耐药的有19株．占21．6％（19／88）；同时对这3种抗生素都敏感的有12株，占13．6％（12／88）；对阿米卡星，庆大霉素和妥布霉素的耐药率分别为22％，69．3％和58％，敏感率分别为70％，22．7％和23．9％。氨基糖苷修饰酶基因aac（3）-Ⅰ和ant（4′）-Ⅱ未检测到；其余6种基因中，aac（3）-Ⅱ，ant（2′′）-Ⅰ，aae（6′）-I，aae（3）-Ⅲ，aae（3）-Ⅳ和aac（6′）-Ⅱ）的检出率分别是2．3％，5．7％，8％，11．4％，11．4％和12．5％。结论临床分离的嗜麦芽窄食单孢菌对氨基糖苷类修饰酶携带率不是很高，但氨基糖苷类抗生素耐药情况却很严重。

Analysis of Aminoglycoside Resistance and Genes of Aminoglycoside Modifying Enzymes in Stenotrophomonas Maltophilia

Objective To investigate the aminoglycoside resistance and existence of aminoglycoside modifying enzymes （AMEs）genes. Method Kirby-Bauer susceptibility method was performed to detect the sensitivity of 88 strains of Stenotrophomonas maltophilia （SMA） to 3 kinds of aminoglyeosides： amikacin, gentamicin, and tobramycin. The existence of aminoglycoside modifying enzymes genes were verified by PCR. Result The susceptibility test showed 21.6% of the 88 strains of SMAs were resistant to all amikacin, gentamicin and tobramycin, while 13.6% of them were susceptible to all these three antibiotics. The susceptible rates to amikacin, gentamicin and tobramycin were 70%, 22.7% and 23.9%, respectively. The resistant rates to amikacin, gentamicin and tobramycin were 22%, 69.3% and 58%, respectively. Aae （3）-Ⅰ and ant （4＇）-Ⅱ were not found in these strains. The positive rates of other 6 kinds of AMEs genes of aac（3）-Ⅱ, ant（2＂）-Ⅰ, aac（6′）-Ⅰ, aac（3）-Ⅲ, aac（3）-Ⅳ, and aac（6′）-Ⅱ were 2.3%, 5.7%, 8%, 10%, 10% and 12.5%, respectively. Conclusion The positive rates of AMEs genes from clinical SMAs were not very high, while their aminoglycoside resistance was much serious.