Department of Bacteriology-Hygiene, Nantes University Hospital, France.
Diagn Microbiol Infect Dis. 2010 Jan;66(1):1-6. doi: 10.1016/j.diagmicrobio.2009.08.014. Epub 2009 Sep 23.
Risk factors for imipenem (IMP)-resistant Pseudomonas aeruginosa (IRPA) digestive carriage were analyzed, and genetic events contributing to select resistant isolates in patients exposed to IMP were investigated. Among the 150 patients with hospital-acquired P. aeruginosa digestive carriage, 38 isolates were IRPA. DNA pulsotypes revealed 16 distinct clones. In 4 patients, a second P. aeruginosa isolate showed resistance to IMP compared with the initial susceptible isolate. By comparing the different oprD sequences between IMP-susceptible P. aeruginosa and IRPA strains, a genetic event was systematically found for each resistant isolate, leading to either the absence of OprD or a truncated porin. The multivariate analysis demonstrated that prior IMP exposure was associated with IRPA carriage. In summary, we confirmed that IMP use selects for IRPA in the gut flora. Cross-transmission, however, was frequently observed in intensive care units. Combining epidemiologic approach and molecular analysis is a powerful tool to delineate mechanisms of emerging resistance.
分析了对亚胺培南（IMP）耐药铜绿假单胞菌（IRPA）消化道定植的危险因素，并研究了在接触 IMP 的患者中导致选择耐药分离株的遗传事件。在 150 例医院获得性铜绿假单胞菌消化道定植的患者中，有 38 株为 IRPA。DNA 脉冲型显示出 16 个不同的克隆。在 4 例患者中，第二株铜绿假单胞菌与初始敏感分离株相比对 IMP 耐药。通过比较 IMP 敏感铜绿假单胞菌和 IRPA 菌株之间不同的 oprD 序列，系统地发现每个耐药分离株都存在 oprD 缺失或截短的外膜孔蛋白。多变量分析表明，先前的 IMP 暴露与 IRPA 定植有关。总之，我们证实了 IMP 的使用会在肠道菌群中选择出 IRPA。然而，在重症监护病房中经常观察到交叉传播。结合流行病学方法和分子分析是阐明新出现耐药机制的有力工具。
