铜绿假单胞菌ampG基因的结构及其对耐药的影响  

The structure of ampG gene in Pseudomonas aeruginosa and its effect on drug resistance

作　　者：张伦军[1] 丁晓琳[1] 张凡[1] 应冲涛 张强[1] ZHANG Lun-jun;DING Xiao-lin;ZHANG Fan;YING Chong-tao;ZHANG Qiang(Department of Laboratory Medicine,the First Affiliated Hospital of Bengbu Medical College,Bengbu,Anhui 233000,China)

机构地区：[1]蚌埠医学院第一附属医院检验科,安徽蚌埠233000

出　　处：《中国卫生检验杂志》2021年第15期1846-1849,共4页Chinese Journal of Health Laboratory Technology

基　　金：蚌埠医学院科技发展基金(KJKF1865)。

摘　　要：目的分析临床分离的铜绿假单胞菌ampG基因结构和功能及其在抗药性方面的影响。方法用VITEK 2Compact全自动微生物分析仪对细菌进行鉴定和药敏分析,对ampG基因全长引物扩增产物进行测序,将PAO1的ampG基因进行点突变实验,研究铜绿假单胞菌中ampG基因的结构与功能的关系。结果在189株PA中有166株测序成功,发现有84株在52个位点上发生了 112次碱基置换,其中C-T间的转换占51.8% (58次),G-A间的转换为25.0% (28次),其余为碱基颠换;在发生的52个位点突变中,有10个引起了氨基酸的改变;2个保守氨基酸(153和W90)基因定点突变时,当153突变为53S或53T (I53S或I53T)时,氨苄西林MIC水平大大下降,AmpC酶活性也明显下降,而W90突变时,氨苄西林的MIC和AmpC酶活性未见明显变化。结论铜绿假单胞菌ampG基因的突变率很高,但AmpG蛋白是稳定的,是维持AmpG正常功能所必需的,在细菌诱导表达β-内酰胺酶的过程中起到重要作用,说明其耐药机制更为复杂。Objective To study the relationship between the structure and function of ampG have been performed against the clinical isolates of Pseudomonas aeruginosa.Methods VITEK 2 Compact automatic microbiological analyzer was used to identify the bacteria and analyze their drug sensitivity.The full-length primer amplification products of ampG gene were sequenced.The point mutation experiment of ampG gene of PA01 was carried out to study the relationship between the structure and function of ampG gene in Pseudomonas aeruginosa.Results Among 189 PA strains,166 were successfully sequenced and 84 were found to have 112 base displacements at 52 sites,which included C-T variation for 51.8%,G-A variation for 25.0%,and the rest were base transversion.Of the 52 site mutations that occurred,10 resulted in amino acid changes;in site-directed mutagenesis of two conserved amino acids(153 and W90),when 153 was mutated to 53 S or 53 T(I53 S or I53T),the MIC level of ampicillin and the activity of AmpC enzyme were significantly decreased,but when W90 was mutated,the MIC and AmpC enzyme activities were not significantly changed.Conclusion The mutation rate of ampG gene in Pseudomonas aeruginosa is high,but the AmpG protein is stable and necessary to maintain the normal function of AmpG,and plays an important role in inducing the expression of β-lactamase in bacteria,suggesting that the mechanism of drug resistance is more complex.

关 键 词：铜绿假单胞菌 ampG基因 耐药性 

分 类 号：R446.5[医药卫生—诊断学]