摘要
目的分析亚胺培南、头孢吡肟、头孢曲松和氨曲南4种β-内酰胺类抗菌药物对阴沟肠杆菌AmpC酶诱导前后耐药性的变化，并对部分突变菌株进行ampD基因的测序及序列分析。方法选择野生型和高诱导型阴沟肠杆菌各5株，进行抗菌药物诱导实验；检测菌株诱导前后的体外抗菌活性（MIC），并进行三维试验、等电点测定及抑制试验的检测，选择诱导突变的1194E菌株4株进行ampD基因扩增、测序。结果β-内酰胺类抗菌药物对野生型菌株诱导前后的MIC值变化不明显，而对高诱导菌株诱导前后的MIC值变化较大，以头孢曲松和氨曲南诱导后的MIC值增高最为明显，可达10．7～128．0倍；ampD基因测序结果提示，经抗菌药物诱导的突变株中，ampD基因序列中有多个位点发生突变，并且发生突变的位点基本相同。结论尽管作为诱导剂的抗菌药物不同，但ampD基因序列中发生突变的位点基本相同。
OBJECTIVE To analyze the resistance of Enterobacter cloacae AmpC β-1actamase with/without being induced by imipenem （IMP）, cefepime （FEP）, ceftriaxone （CRO） and aztreonam （ATM）. The ampD genes of mutant strains were sequenced. METHODS Five wild type strains and 5 hyper-inducible type strains of E. cloacae were selected and induced by the tested antibiotics in vitro. At the same time, antibiotic susceptibility tests,3-D test, isoelectric focusing （IEF） and inhibit experiment were detected to identify hyper-producing AmpC lactamase, ampD Gene sequencing was preformed in part of mutant strains. RESULTS There wasn＇t obvious alteration in MIC with IMP, FEP, CRO and ATM for wild type strains whether they were induced or not. But, for the hyper-inducible type, there was apparent increasing in MIC after antibiotics inducing, especially CRO and ATM, up to 10. 7-128 times. The DNA sequences analysis in the mutation strains showed there existed the replacement of the single base in multiple sites, and a few sites of amino acid were altered. CONCLUSIONS Mutant sites in ampD gene sequences are identical even though antibiotics as inducer are different.
出处
《中华医院感染学杂志》
CAS
CSCD
北大核心
2007年第2期125-128,共4页
Chinese Journal of Nosocomiology
