儿科患者鲍曼不动杆菌氨基糖苷类修饰酶基因的表达

The expression of seven kinds of aminoglycoside-modifying enzymes genes of Acinetobacter baumannii isolated in pediatric patients

目的研究从儿科肺炎患者中分离的鲍曼不动杆菌对氨基糖苷类抗生素的耐药性和常见的7种氨基糖苷类修饰酶基因特征。方法56株鲍曼不动杆菌(AB)收集自2006年分离的儿科临床肺炎患儿的深部痰培养标本,均采用VITEK-32全自动微生物鉴定仪GNI和GNS卡进行细菌鉴定和药敏试验。氨基糖苷类修饰酶基因检测采用聚合酶链式反应(PCR)方法。结果检测的56株鲍曼不动杆菌菌有8株呈多重耐药性,阳性率14.29%,8株多重耐药菌对氨基糖苷类药物阿米卡星、妥布霉素和庆大霉素均耐药,其余菌株对氨基糖苷类药物均敏感,氨基糖苷类药物的耐药率14.29%。除呋喃妥因及β-内酰胺类抗生素氨苄西林、头孢唑林和头孢曲松外其它抗生素的耐药率均在15%以下。7种氨基糖苷类修饰酶基因中检出2株aac(3)-Ⅱ(3.57%),2株aac(6')-Ⅰb(3.57%),4株aac(6')-Ⅱ(7.14%),6株ant(3″)-Ⅰ(10.71%);aac(3)-Ⅰ、ant(2″)-Ⅰ和aac(6')-Ⅰad均阴性。对3种氨基糖苷类抗生素耐药的菌株均检出了氨基糖苷类修饰酶基因。结论(1)儿科患者虽然极少应用氨基糖苷类抗生素,但由于氨基糖苷类修饰酶基因可借助于整合子、转座子和质粒等在同种和异种细菌间传播,使其对氨基糖苷类抗生素也产生了一定的耐药性。(2)鲍曼不动杆菌儿科患者分离株对阿米卡星、庆大霉素和妥布霉素的耐药与aac(3)-Ⅱ、aac(6')-Ⅰb、aac(6')-Ⅱ和ant(3″)-Ⅰ四种基因有关。不同地区细菌的修饰酶基因有很大差异,而儿童与成人患者亦有不同,因此要重视儿科患者鲍曼不动杆菌氨基糖苷类抗生素耐药性和耐药基因研究。

Objective To study the aminoglycosides resistance and the seven kinds of common aminoglycoside-modifying enzymes（AMEs） genes in Acinetobacter baumannii isolates. Methods Fifty-six strains isolates were collected from the sputum samples in children with pneumonia in 2006, and antimicrobial susceptibility testing were performed by VITEK-32 automicroscan using GNI and GNS cards, respectively. AMEs genes were analyzed by polymerase chain reaction （PCR）. Results For 56 tested strains, 8 strains showed muhidrug resistance （the positive rate, 14. 29% ） and conferred resistant to the aminoglycosides including amikacin,tobramycin and gentamicin,the other 48 strains were completely sensitive to aminoglycosides （the resistance rate, 14. 29% ）. Apart from ampicillin, cephazolin, nitrofurantoin and ceftriaxone, the resistance rates of isolates against the other antibiotics were all below 15%. With detecting 7 types AMEs genes, 2 strains of aac（3） -Ⅱ（3.57% ）, 2 strains of aac（6＇） - Ⅰb （3.57%）,4 strains of aac（6＇） -Ⅱ （7. 14% ）and 6 strains of ant（3＂） - Ⅰ （10. 71% ） were discovered, but aac（3） - Ⅰ, ant（2＂） - land aac（6＇）- Ⅰad were negative. Different AMEs genes were confirmed in those strains that were resistant to above three kinds of aminoglyeosides. Conclusions （1）Although aminoglycosides were rarely used in pediatric patients, while AMEs genes could draw assistance from integron, transposon, plasmid and so on, and spread both in same sorts of bacteria and in different ones, therefore the isolates from children patients also showed certain drug resistance to aminoglycosides. （2）The resistance of isolates in children patients to amikacin, tobramycin and gentamicin were related to aac（3）-Ⅱ, aac（6＇）-Ⅰb, aac（6＇）-Ⅱ εnd ant（3＂）-Ⅰgenes. Bacterial modification genes were significantly different in various areas, there were differences between children and adult patients, so the aminoglycosides resistance and AMEs genes of Acinetobacter baumannii in children patients should pay attention to therapeutic research.