Guan Xi-zhou, Liu You-ning, Luo Yan-ping, She Dan-yang, Zhou Guang, Chen Liang-an, Xu Ya-ping
Department of Respiratory Medicine, General Hospital of Chinese People's Liberation Army, Beijing 100853, China.
Zhonghua Jie He He Hu Xi Za Zhi. 2005 Jul;28(7):475-8.
To study the prevalence, phenotype and genotype of the AmpC and ESBLs-producing clinical isolate of Klebsiella pneumoniae.
The clinical isolates of Klebsiella pneumoniae were examined by standard disk diffusion susceptibility tests, three-dimensional methods, isoelectric focusing (IEF) and microdilution methods. The conjugation experiment, multiplex PCR and DNA sequencing methods were used for further analysis.
Four out of a total of 86 isolates tested were shown to be highly AmpC-producing by three-dimensional method. IEF showed that these strains produced a AmpC like beta-lactamase with a PI of 7.8, and DNA sequencing showed that the gene which expressed this AmpC like beta-lactamase was identical to DHA-1, a plasmid mediated cephalosporinase gene. These strains also produced an ESBL like beta-lactamase with a PI of 8.2 and the gene which expressed this beta-lactamase was identical to SHV-12. These strains were resistant not only to most of the third generation cephalosporins, but also to cefepime. However they were still susceptible to carbapenem.
Highly AmpC-producing DHA-1 accompanied with SHV-12 in Klebsiella pneumoniae was reported here for the first time. They result in a significant rise in antibiotic resistance, which is regarded as a great challenge for clinical antibiotic therapy.
研究产AmpC酶及超广谱β-内酰胺酶（ESBLs）的肺炎克雷伯菌临床分离株的流行情况、表型及基因型。
采用标准纸片扩散药敏试验、三维试验、等电聚焦（IEF）及微量稀释法对肺炎克雷伯菌临床分离株进行检测。采用接合试验、多重聚合酶链反应（PCR）及DNA测序方法进行进一步分析。
86株受试菌株中，三维试验显示有4株为高产AmpC酶菌株。IEF显示这些菌株产生一种等电点为7.8的AmpC样β-内酰胺酶，DNA测序显示表达此AmpC样β-内酰胺酶的基因与DHA-1相同，DHA-1是一种质粒介导的头孢菌素酶基因。这些菌株还产生一种等电点为8.2的ESBL样β-内酰胺酶，表达此β-内酰胺酶的基因与SHV-12相同。这些菌株不仅对大多数第三代头孢菌素耐药，而且对头孢吡肟耐药。然而，它们对碳青霉烯类仍敏感。
本文首次报道了肺炎克雷伯菌中高产AmpC酶的DHA-1与SHV-12共存的情况。它们导致抗生素耐药性显著上升，这被认为是临床抗生素治疗面临的巨大挑战。
