Regulation of P. aeruginosa PoxB Oxacillinase by AmpR and a Two-Component System

AmpR 和双组分系统对铜绿假单胞菌 PoxB 苯唑西林酶的调节

• 批准号: 7425684
• 负责人: KALAI MATHEE
• 金额: $ 29.58万
• 依托单位: FLORIDA INTERNATIONAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7425684
• 关键词: Alginates; Amidohydrolases; AmpC Genes; Antibiotic Resistance; Antibiotics; Appearance; Biological; Cessation of life; Chronic; Clinical; Cystic Fibrosis; Development; Enzymes; Event; Family; Genes; Genetic; Genetic Transcription; Genome; Goals; Grant; Homologous Gene; Hydrolysis; Immune response; Infection; Lactamase; Lactams; Lead; Messenger RNA; Molecular; Molecular Genetics; Morbidity - disease rate; Operon; Organism; Play; Pseudomonas aeruginosa; Regulation; Resistance; Resistance development; Role; System; Techniques; Testing; Virulent; Work; amidase; base; cystic fibrosis patients; derepression; in vivo; insight; member; mortality; mucoid; novel therapeutics; permease; research study; response; sensor

DESCRIPTION (provided by applicant): Two critical hallmarks of chronic Pseudomonas aeruginosa infection in patients with cystic fibrosis (CF) are the appearance of alginate over-producing mucoid colonies and the development of antibiotic resistance. A rapid emergence of antibiotic resistance in P. aeruginosa isolates in CF patients due to in vivo selection of strains that overproduce AmpC ¿-lactamase, an enzyme that hydrolyzes the ¿-lactams, contributes to both morbidity and mortality. Previous studies investigating the regulation of the amp genes in P. aeruginosa using genetic and molecular biological techniques led to the identification of a second ¿-lactamase, PoxB oxacillinase. We showed that the expression of both ampC and poxB are under the control of AmpR, a member of the LysR family of transcriptional regulators. We have demonstrated that AmpR is a global transcriptional regulator which regulates expression of many virulent genes that are important for establishing chronic infections. Our long-term goal is to establish the regulatory circuit that exists between the amp and pox genes and their role in the development of resistance to ¿-lactams and the establishment of chronic infection. To date, we know very little about the molecular mechanisms that govern the expression of pox operon. The experiments proposed in this grant will extend our understanding as they will focus on (1) characterizing the poxAB operon and determining if AmpR regulation is by transcriptional derepression, and (2) determining if expression of the poxAB operon is regulated by a previously uncharacterized two-component system. These analyses will provide invaluable insight into the bacterial adaptation to the onslaught of antibiotics and the immune response. It will likely lead to novel therapeutic approaches in combating the persistent P. aeruginosa infection that ultimately leads to the untimely death of CF patients.

描述（由申请人提供）：囊性纤维化（CF）患者慢性铜绿假单胞菌感染的两个关键特征是藻酸盐过量产生粘液样菌落的出现和抗生素耐药性的发展铜绿假单胞菌中抗生素耐药性的迅速出现。由于体内选择了过量产生 AmpC 的菌株，CF 患者中出现了分离株 ¿ -内酰胺酶，一种水解 ¿ -内酰胺，导致发病率和死亡率。之前的研究使用遗传和分子生​​物学技术研究了铜绿假单胞菌中的 amp 基因的调节，导致了第二个 ¿ -内酰胺酶、PoxB 苯唑西林酶 我们证明 ampC 和 poxB 的表达均受 AmpR 的控制，AmpR 是转录调节因子 LysR 家族的成员。这对于建立慢性感染很重要。 我们的长期目标是建立 amp 和 pox 基因之间存在的调节回路及其在抗性发展中的作用 ¿迄今为止，我们对控制 pox 操纵子表达的分子机制知之甚少，本次资助中提出的实验将扩展我们的理解，因为它们将集中于 (1) 表征 poxAB 操纵子。 (2) 确定 poxAB 操纵子的表达是否受到先前未表征的双组分系统的调节。这些分析将为细菌适应提供宝贵的见解。抗生素和免疫反应的冲击可能会带来新的治疗方法来对抗持续性铜绿假单胞菌感染，最终导致 CF 患者过早死亡。