来自利文斯顿希瓦氏菌（SLB-1）和嗜冷希瓦氏菌（SFB-1）的染色体编码B类β-内酰胺酶的遗传和生化特性
Genetic and biochemical characterization of the chromosome-encoded class B beta-lactamases from Shewanella livingstonensis (SLB-1) and Shewanella frigidimarina (SFB-1).
作者信息
Poirel Laurent, Héritier Claire, Nordmann Patrice
机构信息
Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, 78 rue du Général Leclerc, 94275 Le Kremlin-Bicêtre Cedex, France.
出版信息
J Antimicrob Chemother. 2005 May;55(5):680-5. doi: 10.1093/jac/dki065. Epub 2005 Mar 16.
OBJECTIVES
To determine the beta-lactamase gene content of beta-lactam-susceptible psychrophilic gram-negative bacilli, Shewanella frigidimarina and Shewanella livingstonensis, isolated from a marine environment.
METHODS
Beta-lactamase genes were cloned, sequenced and expressed in Escherichia coli. Kinetic parameters were determined using purified enzymes.
RESULTS
Metallo-beta-lactamases SLB-1 and SFB-1 were identified from S. livingstonensis and S. frigidimarina, respectively, sharing 65% amino acid identity and being distantly related to other Ambler class B beta-lactamases (40 and 36% amino acid identity with GIM-1 and IMP-1 from Pseudomonas aeruginosa, respectively). SLB-1 had an EDTA-inhibited and broad-spectrum beta-lactam hydrolysis profile, whereas SFB-1 did not hydrolyse cephalosporins, with activity being weakly inhibited by EDTA and dipicolinic acid.
CONCLUSIONS
This work provides further evidence that psychrophilic bacterial species may constitute a reservoir of beta-lactam resistance genes.
目的
确定从海洋环境中分离出的对β-内酰胺敏感的嗜冷革兰氏阴性杆菌——嗜冷希瓦氏菌和利文斯顿希瓦氏菌的β-内酰胺酶基因含量。
方法
将β-内酰胺酶基因进行克隆、测序并在大肠杆菌中表达。使用纯化的酶测定动力学参数。
结果
分别从利文斯顿希瓦氏菌和嗜冷希瓦氏菌中鉴定出金属β-内酰胺酶SLB-1和SFB-1，它们的氨基酸同一性为65%，与其他安布勒B类β-内酰胺酶亲缘关系较远（分别与铜绿假单胞菌的GIM-1和IMP-1的氨基酸同一性为40%和36%）。SLB-1具有受EDTA抑制的广谱β-内酰胺水解谱，而SFB-1不水解头孢菌素，其活性受到EDTA和二吡啶甲酸的微弱抑制。
结论
这项工作进一步证明嗜冷细菌物种可能构成β-内酰胺抗性基因的储存库。
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