未经碳青霉烯类抗生素治疗患者中检出亚胺培南不敏感铜绿假单胞菌  

Characterization of imipenem non-susceptible Pseudomonas aeruginosa isolates from patients without carbapenem treatment

作　　者：辜依海[1] 朱啸[2] 崔生辉[3] 张军[1] 周庆元[4] 李景云[3] 

机构地区：[1]西安交通大学医学院附属三二0一医院检验科,汉中723000 [2]澳门镜湖医院口腔科 [3]中国药品生物制品检定所抗生素室 [4]西安交通大学医学院呼吸科

出　　处：《中华检验医学杂志》2012年第8期716-721,共6页Chinese Journal of Laboratory Medicine

摘　　要：目的通过对未使用碳青霉烯类药物治疗患者中分离的亚胺培南耐药铜绿假单胞菌的分型分析，探讨铜绿假单胞菌对亚胺培南耐药性产生和传播的危险因素。方法2006年4月至2008年3月西安交通大学医学院附属三二。一医院从未使用碳青霉烯治疗的住院患者中分离出37株亚胺培南不敏感铜绿假单胞菌，采用琼脂稀释法测定了菌株对11种抗生素的敏感性，并通过肉汤稀释法测试了外排泵抑制剂（PABN）对亚胺培南和美罗培南耐药性的影响。通过PCR方法对金属酶编码基因及外膜孔蛋白编码基因oprD2进行了扩增和测序，用实时定量PCR（1iT—PCR）方法对oprD：和ampC基因的表达水平进行测定，采用脉冲场电泳技术（PFGE）分析菌株的同源性。结果37例患者中，体内分离出亚胺培南不敏感铜绿假单胞菌之前，使用两种或两种以上抗生素治疗的16例患者平均抗生素使用时间为（20．0±9．5）d，显著长于仅使用一种抗生素治疗的21例患者[（12．6±4．4）d；t=-2．9004，P〈0．01]。在37株菌中，32株对3种以上抗生素耐药；仅有1株菌检出金属酶（IMP-9型），但该菌金属酶表型为阴性；29株菌的oprD：基因上均在同一位点正向插入序列ISpal328；oprD：表达量检测有35株菌为零表达，2株菌过度表达ampC酶；37株菌PFGE分型分为6个脉冲型，其中26株菌为c2型；所有37株菌在外排泵抑制剂作用下，表现出外排功能。结论氟喹诺酮类和头孢类抗生素是铜绿假单胞菌对碳青霉烯类抗生素不敏感的重要因素。Objectives To investigate characterization of imipenem resistance among imipenem non susceptible Psettdomonas aeruginosa isolated from patients who treated without imipenem and explore risk factors of imipenem resistance. Methods From April, 2006 to March, 2008, a total of 37 non-susceptible to imipenem without imipenem therapy isolates were collected from affiliated 3201st Hospital of Medical College of Xi＇an Jiaotong University. The minimum inhibition concentration （MIC） to 11 antimicrobial agents were determined by the broth dilution method. We also tested imipenem MIC combined with efflux pump inhibitor PAI3N. PCR was performed to check for the presence of carbapenem-hydrolylzing MBL genes and oprD gene. The expression level of oprD2 and ampC were evaluated by qRT-PCR. Molecular typing was performed using PFGE. Results There is significant difference （ t = - 2. 9004, P 〈 0. O1 ） of the average number days of therapy between with two or more antibiotics in the 16 patients （20. 0 ＋ 9. 5 ） d and that with only one antibiotic in the other 21 patients （ 12. 6 ＋ 4. 4 ） d before imipenem-non-susceptible strains were isolated. In all 37 strains, 32 strains showed resistance to more than three antibiotics. The MBL gene （IMP- 9） was only found in one strain, but its phenotype is negative, oprD2 gene from the 29 strains were found forward inserted by ISpa1328. Thirty-five isolated were considered to have no oprD expression. The patterns of the total DNA of 37 strains appeared six PFGE types. The 26 strains belonged to C2 PFGE type. In the presence of PAI3N, all 37 strains increased sensitivity to meropenem. Conclusion Fluoroquinolones and cephalosporins treatment could play an important role in imipenem non-susceptible production in the research isolates.

关 键 词：假单胞菌 铜绿 亚胺培南 抗药性 细菌 

分 类 号：R446.5[医药卫生—诊断学]