Increased energy demand from anabolic-catabolic processes drives β-lactam antibiotic lethality

Abstract

b-Lactam antibiotics disrupt the assembly of peptidoglycan (PG) within the bacterial cell wall by inhibiting the enzymatic activity of penicillin-binding proteins (PBPs). It was recently shown that b-lactam treatment initializes a futile cycle of PG synthesis and degradation, highlighting major gaps in our understanding of the lethal effects of PBP inhibition by b-lactam antibiotics. Here, we assess the downstream metabolic consequences of treatment of Escherichia coli with the b-lactam mecillinam and show that lethality from PBP2 inhibition is a specific consequence of toxic metabolic shifts induced by energy demand from multiple catabolic and anabolic processes, including accelerated protein synthesis downstream of PG futile cycling. Resource allocation into these processes is coincident with alterations in ATP synthesis and utilization, as well as a broadly dysregulated cellular redox environment. These results indicate that the disruption of normal anabolic-catabolic homeostasis by PBP inhibition is an essential factor for b-lactam antibiotic lethality.

Central metabolism is a key player in E. coli biofilm stimulation by sub-MIC antibiotics

“…The maximal level of biofilm stimulation for deletion mutants of acnA (encoding aconitase), lpdA (encoding lipoamide dehydrogenase), nuoE (encoding subunit of complex I in the electron transport chain), lpp (encoding Braun's lipoprotein), and ydcU (encoding a predicted polyamine transporter) was markedly reduced upon treatment with sub-MIC NOVO or CEF compared to the wild type. The hits were enriched for mutants in central metabolism and respiration (Figure 2a), consistent with previous studies suggesting that antibiotics alter metabolic state and respiration as a part of their lethality (Belenky et al, 2015;Dwyer et al, 2014;Lobritz et al, 2022Lobritz et al, , 2015Stokes, Lopatkin, Lobritz, & Collins, 2019). Thus, we focused on acnA, acnB, lpdA, and nuoE for further examination because of their common roles in central carbon metabolism and aerobic respiration (Karp et al, 2018).…”

Strain-specific predation of Bdellovibrio bacteriovorus on Pseudomonas aeruginosa with a higher range for cystic fibrosis than for bacteremia isolates

“…Inside the “common metabolism” when the predator is placed into the prey, massive PHA degradation yields an ATP excess, which is known to increase reactive oxygen species, which can oxidize and damage DNA, carbohydrates, proteins, or lipids 38 , 39 . Excess ATP also triggers respiration, but in small cells (such as Bdellovibrio ) the question is whether high ATP levels are incompatible with the maintenance of respiration if the surface of the cell cannot allocate enough respiratory proteins 40 , 41 . In short, PHA defective mutants might have unexpected metabolic consequences 42 – 46 influencing predation activity, and research in this field could help to identify and eventually overcome predation resistance factors in P. aeruginosa .…”

A whole-genome assay identifies four principal gene functions that confer tolerance of meropenem stress upon Escherichia coli

“…A combination of these effects may be conducive to maintenance of the redox environment. However, our data point towards the importance of maintaining the membrane potential for meropenem tolerance; a consideration that was not directly addressed in (Lobritz et al, 2022).…”

“…This damages macromolecules such as DNA and proteins, leading to increased protein synthesis, which further increases energy demand. The eventual depletion of ATP and accumulated cell damage leads to death (Lobritz et al, 2022). Although so far only demonstrated for mecillinam, this runaway process of cell damage intriguingly implicates our other two principal gene functions of ATP metabolism and transcription regulation in a network of farreaching downstream effects from b-lactam-induced cell envelope stress.…”