抗生素压力下铜绿假单胞菌耐药机制变化的动态研究  

Change of antimicrobial resistance in Pseudomonas aeruginosa under the antibiotic pressure

作　　者：郭仲辉[1] 黎毓光[1] 卓超[2] 

机构地区：[1]广州市番禺区人民医院,广州511400 [2]广州医学院呼吸疾病国家重点实验室,广州510230

出　　处：《中国抗生素杂志》2010年第9期715-720,共6页Chinese Journal of Antibiotics

基　　金：广州市番禺区科学技术局科技攻关项目(2007-Z-61-1);广州市科技局重点攻关项目(2006Z1-E0141)

摘　　要：目的探索抗生素压力下铜绿假单胞菌在患者呼吸道内耐药性的动态改变。方法以同一患者不同时期下呼吸道分离铜绿假单胞菌为对象,E-test检测细菌对常用抗菌药物的敏感性;三维水解实验检测目标菌的β-内酰胺酶表型特征;普通PCR检测ESBL、AmpC、碳青霉烯水解酶、膜孔蛋白OprD2等耐药基因;荧光定量RT-PCR检测细菌的AmpC和OprD2的表达情况。结果筛查到1例因慢性阻塞性肺病急性发作(AECOPD)患者3次入院、下呼吸道分离的属同一克隆的9株铜绿假单胞菌,药敏试验提示细菌的药敏谱存在由单一耐药逐渐转化为泛耐药的模式。三维水解实验显示,5株多重耐药株和泛耐药株高产AmpC酶。所有9株菌的ampC和oprD2基因都为阳性,碳青霉烯水解酶均为阴性。荧光定量RT-PCR检测,多重耐药株和泛耐药株的ampC基因表达量是单一耐药株的1.7～18.7倍;亚胺培南耐药株的oprD2表达量则是敏感株的1/10～1/2000。结论铜绿假单胞菌在治疗过程中可获得耐药性,其中ampC高表达和oprD2表达下降是导致细菌对亚胺培南、广谱头孢菌素(含酶抑制剂)耐药的主要原因。Objective To explore the change of antimicrobial resistance of clinical isolates of Pseudomonas aeruginosa isolated from lower respiratory tract of AECOPD patient under the antibiotic pressure. Methods The strains of P aeruginosa isolated from sputum samples were collected from the same patient with different hospitalization. E-test method was employed to detect drug sensitivity. Three-dimensional test was used to identify the different kinds of β-1actamase produced the strains. PCR method was performed to detect ESBLs, AmpC, carbapenemase genes and oprD2 gene. The expression of the chromosomal ampC beta lactamases and oprD2 genes in the strains were analyzed by real-time PCR. Results Nine isolates isolated from 3 times in hospitalization were analyzed after identified to be one clone. The antimicrobial susceptibility of nine isolates displayed an interesting evolution from being susceptible to some examined drugs to being resistant to all examined drugs. High production of AmpC was detected by three-dimensional test in 5 MDR strains, and overexpression of ampC gene were also detected by fluorescence quantitative RT-PCR in 8 MDR strains, and the amount of ampC expression is 1.7-18.7 times than that in S-PA. Carbapenemase genes weren＇t detected in all the strains. 8 isolates with diminished expression of oprD2 were IPM resistance. Conclusion High expression of ampC and oprD2 diminished expression emerged in the treatment of Pseudomonas aeruginosa, which resulted in bacterial resistance to imipenem, broad-spectrum cephalosporin （including enzyme inhibitors）.

关 键 词：铜绿假单胞菌 AMPC酶 OPRD2 抗生素压力 

分 类 号：R378[医药卫生—病原生物学]