Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA.
Department of Microbiology, Cornell University, Ithaca, New York, USA.
J Bacteriol. 2023 Mar 21;205(3):e0047622. doi: 10.1128/jb.00476-22. Epub 2023 Feb 22.
Antibiotic tolerance, the ability of bacteria to sustain viability in the presence of typically bactericidal antibiotics for extended time periods, is an understudied contributor to treatment failure. The Gram-negative pathogen Vibrio cholerae, the causative agent of cholera, becomes highly tolerant to β-lactam antibiotics (penicillin and related compounds) in a process requiring the two-component system VxrAB. VxrAB is induced by exposure to cell wall damaging conditions, which results in the differential regulation of >100 genes. While the effectors of VxrAB are relatively well known, VxrAB environment-sensing and activation mechanisms remain a mystery. Here, we used transposon mutagenesis to screen for mutants that spontaneously upregulate VxrAB signaling. This screen was answered by genes known to be required for proper cell envelope homeostasis, validating the approach. Unexpectedly, we also uncovered a new connection between central carbon metabolism and antibiotic tolerance in Vibrio cholerae. Inactivation of ( coding for glucose-6-phosphate isomerase) resulted in an intracellular accumulation of glucose-6-phosphate and fructose-6-phosphate, concomitant with a marked cell envelope defect, resulting in VxrAB induction. Deletion of also increased sensitivity to β-lactams and conferred a growth defect on salt-free LB, phenotypes that could be suppressed by deleting sugar uptake systems and by supplementing cell wall precursors in the growth medium. Our data suggest an important connection between central metabolism and cell envelope integrity and highlight a potential new target for developing novel antimicrobial agents. Antibiotic tolerance (the ability to survive exposure to antibiotics) is a stepping stone toward antibiotic resistance (the ability to grow in the presence of antibiotics), an increasingly common cause of antibiotic treatment failure. The mechanisms promoting tolerance are poorly understood. Here, we identified central carbon metabolism as a key contributor to antibiotic tolerance and resistance. A strain with a mutation in a sugar utilization pathway accumulates metabolites that likely shut down the synthesis of cell wall precursors, which weakens the cell wall and thus increases susceptibility to cell wall-active drugs. Our results illuminate the connection between central carbon metabolism and cell wall homeostasis in V. cholerae and suggest that interfering with metabolism may be a fruitful future strategy for the development of antibiotic adjuvants.
抗生素耐受是指细菌在长时间接触通常具有杀菌作用的抗生素时仍能存活的能力，是导致治疗失败的一个研究不足的因素。革兰氏阴性病原体霍乱弧菌是霍乱的病原体，它在一个需要双组分系统 VxrAB 的过程中对β-内酰胺抗生素（青霉素和相关化合物）产生高度耐受。VxrAB 是由暴露于细胞壁损伤条件诱导产生的，这导致了超过 100 个基因的差异调节。虽然 VxrAB 的效应物相对较为清楚，但 VxrAB 的环境感应和激活机制仍然是一个谜。在这里，我们使用转座子诱变筛选自发上调 VxrAB 信号的突变体。这个筛选由已知对适当的细胞包膜稳态所必需的基因回答，验证了该方法的有效性。出乎意料的是，我们还在霍乱弧菌中发现了中央碳代谢与抗生素耐受之间的新联系。（编码葡萄糖-6-磷酸异构酶）的失活导致葡萄糖-6-磷酸和果糖-6-磷酸在细胞内积累，同时伴随着明显的细胞包膜缺陷，导致 VxrAB 的诱导。的缺失也增加了对β-内酰胺的敏感性，并在无盐 LB 上赋予了生长缺陷，这些表型可以通过删除糖摄取系统和在生长培养基中补充细胞壁前体来抑制。我们的数据表明中央代谢与细胞包膜完整性之间存在重要联系，并突出了开发新型抗菌剂的潜在新靶标。抗生素耐受（暴露于抗生素时存活的能力）是抗生素耐药性（在抗生素存在下生长的能力）的一个垫脚石，抗生素耐药性是抗生素治疗失败的一个越来越常见的原因。促进耐受的机制还不太清楚。在这里，我们确定了中央碳代谢是抗生素耐受和耐药性的关键因素。一个突变了糖利用途径的菌株会积累可能会抑制细胞壁前体合成的代谢物，从而削弱细胞壁，从而增加对细胞壁活性药物的敏感性。我们的结果阐明了中央碳代谢与霍乱弧菌细胞壁稳态之间的联系，并表明干扰代谢可能是开发抗生素佐剂的一个有前途的未来策略。
