抗生素活性受到革兰氏阴性细胞包膜的物理结构的限制。洋葱伯克霍尔德氏菌(Bcc)的物种被认为是具有低通透性细胞包膜的固有多药耐药机会病原体。这里,我们重新检查了先前进行的化学-遗传筛选的条形码转座子突变体在银花芽孢杆菌K56-2,重点是细胞的包膜结构和功能过程。我们确定了对单一和多种抗生素类别的抗性在机械上重要的结构。例如,对新生霉素的易感性,阿维巴坦,和LpxC抑制剂,PF-04753299,连接到BpeAB-OprB外排泵,表明这些药物是这种泵的底物。肽聚糖前体合成中的缺陷特别增加了对环丝氨酸的敏感性,并揭示了一种新的推定氨基酸消旋酶,而分裂辅助蛋白的缺陷增加了对多种β-内酰胺的敏感性。此外,周质二硫键形成系统的破坏导致外膜完整性和β-内酰胺酶活性的多效性缺陷。我们的发现强调了细胞包膜结构和功能中抗性机制的分层。因此,我们指出了可以用于开发抗生素增效剂的方法。重要性革兰氏阴性细胞包膜是一种双层物理屏障,可保护细胞免受细胞外应激源的影响,比如抗生素。已知伯克霍尔德氏菌细胞包膜含有降低渗透性的额外修饰。我们通过重新检查暴露于抗生素小组的转座子突变体文库的数据,从全基因组的角度研究了伯克霍尔德氏菌细胞包膜因子对抗生素耐药性的影响。我们确定了外膜结构和功能缺陷的易感表型,周质,和细胞质。总的来说,我们表明,与细胞包膜相关的抗性是多方面的,并为开发抗生素增效剂提供了新的靶标。
Antibiotic activity is limited by the physical construction of the Gram-negative cell envelope. Species of the Burkholderia cepacia complex (Bcc) are known as intrinsically multidrug-resistant opportunistic pathogens with low permeability cell envelopes. Here, we re-examined a previously performed chemical-genetic screen of barcoded transposon mutants in B. cenocepacia K56-2, focusing on cell envelope structural and functional processes. We identified structures mechanistically important for resistance to singular and multiple antibiotic classes. For example, susceptibility to novobiocin, avibactam, and the LpxC inhibitor, PF-04753299, was linked to the BpeAB-OprB efflux pump, suggesting these drugs are substrates for this pump in B. cenocepacia. Defects in peptidoglycan precursor synthesis specifically increased susceptibility to cycloserine and revealed a new putative amino acid racemase, while defects in divisome accessory proteins increased susceptibility to multiple β-lactams. Additionally, disruption of the periplasmic disulfide bond formation system caused pleiotropic defects on outer membrane integrity and β-lactamase activity. Our findings highlight the layering of resistance mechanisms in the structure and function of the cell envelope. Consequently, we point out processes that can be targeted for developing antibiotic potentiators.IMPORTANCEThe Gram-negative cell envelope is a double-layered physical barrier that protects cells from extracellular stressors, such as antibiotics. The Burkholderia cell envelope is known to contain additional modifications that reduce permeability. We investigated Burkholderia cell envelope factors contributing to antibiotic resistance from a genome-wide view by re-examining data from a transposon mutant library exposed to an antibiotic panel. We identified susceptible phenotypes for defects in structures and functions in the outer membrane, periplasm, and cytoplasm. Overall, we show that resistance linked to the cell envelope is multifaceted and provides new targets for the development of antibiotic potentiators.