首页> 外文OA文献 >Genetic and Biochemical Characterization of OXA-63, a New Class D β-Lactamase from Brachyspira pilosicoli BM4442▿
【2h】

Genetic and Biochemical Characterization of OXA-63, a New Class D β-Lactamase from Brachyspira pilosicoli BM4442▿

机译:短螺旋体BM4442▿的新型D类β-内酰胺酶OXA-63的遗传和生化特性

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

Brachyspira pilosicoli BM4442, isolated from the feces of a patient with diarrhea at the Hospital Saint-Michel in Paris, was resistant to oxacillin (MIC > 256 μg/ml) but remained susceptible to cephalosporins and to the combination of amoxicillin and clavulanic acid. Cloning and sequencing of the corresponding resistance determinant revealed a coding sequence of 807 bp encoding a new class D β-lactamase named OXA-63. The blaOXA-63 gene was chromosomally located and not part of a transposon or of an integron. OXA-63 shared 54% identity with FUS-1 (OXA-85), an oxacillinase from Fusobacterium nucleatum subsp. polymorphum, and 25 to 44% identity with other class D β-lactamases (DBLs) and contained all the conserved structural motifs of DBLs. Escherichia coli carrying the blaOXA-63 gene exhibited resistance to benzylpenicillin and amoxicillin but remained susceptible to amoxicillin in combination with clavulanic acid. Mature OXA-63 consisted of a 31.5-kDa polypeptide and appeared to be dimeric. Kinetic analysis revealed that OXA-63 exhibited a narrow substrate profile, hydrolyzing oxacillin, benzylpenicillin, and ampicillin with catalytic efficiencies of 980, 250, and 150 mM−1 s−1, respectively. The enzyme did not apparently interact with oxyimino-cephalosporins, imipenem, or aztreonam. Unlike FUS-1 and other DBLs, OXA-63 was strongly inhibited by clavulanic acid (50% inhibitory concentration [IC50] of 2 μM) and tazobactam (IC50 of 0.16 μM) and exhibited low susceptibility to NaCl (IC50 of >2 M). OXA-63 is the first DBL described for the anaerobic spirochete B. pilosicoli.
机译:从巴黎圣米歇尔医院腹泻患者的粪便中分离出的短螺旋体BM4442对奥沙西林(MIC> 256μg/ ml)有抗药性,但仍对头孢菌素以及阿莫西林和克拉维酸的组合敏感。相应抗性决定簇的克隆和测序揭示了一个807 bp的编码序列,该编码新的D类β-内酰胺酶名为OXA-63。 blaOXA-63基因位于染色体上,不属于转座子或整合子的一部分。 OXA-63与FUS-1(OXA-85)具有54%的同一性,FUS-1是来自Fusobacterium nucleatum亚种的草酸酶。多形性,并与其他D类β-内酰胺酶(DBLs)具有25%至44%的同一性,并且包含所有保守的DBLs结构基序。携带blaOXA-63基因的大肠杆菌对苄青霉素和阿莫西林表现出抗药性,但与克拉维酸联合使用时仍对阿莫西林敏感。成熟的OXA-63由31.5-kDa多肽组成,似乎是二聚体。动力学分析表明,OXA-63表现出较窄的底物分布,水解奥沙西林,苄青霉素和氨苄青霉素,催化效率分别为980、250和150 mM-1 s-1。该酶显然与氧亚氨基头孢菌素,亚胺培南或氨曲南没有相互作用。不同于FUS-1和其他DBL,OXA-63被棒酸(50%抑制浓度[IC50]为2μM)和他唑巴坦(IC50为0.16μM)强烈抑制,对NaCl的敏感性较低(IC50> 2 M) 。 OXA-63是描述的厌氧螺旋体双歧杆菌B. pilosicoli的第一个DBL。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号