RT Journal Article T1 Disbalancing Envelope Stress Responses as a Strategy for Sensitization of Escherichia coli to Antimicrobial Agents A1 Recacha, Esther A1 Fox, Valeria A1 Díaz-Díaz, Sara A1 García-Duque, Ana A1 Docobo-Pérez, Fernando A1 Pascual, Álvaro A1 Rodríguez-Martínez, José Manuel K1 Envelope stress responses K1 Bacterial sensitization K1 Beta-lactams K1 Antimicrobial resistance K1 Gram-negative bacteria K1 Escherichia coli K1 Aztreonam K1 Ceftazidime K1 Estrés K1 beta-Lactamas K1 Farmacorresistencia microbiana K1 Bacterias gramnegativas K1 Ceftazidima AB Disbalancing envelope stress responses was investigated as a strategy for sensitization of Escherichia coli to antimicrobial agents. Seventeen isogenic strains were selected from the KEIO collection with deletions in genes corresponding to the σE, Cpx, Rcs, Bae, and Psp responses. Antimicrobial activity against 20 drugs with different targets was evaluated by disk diffusion and gradient strip tests. Growth curves and time-kill curves were also determined for selected mutant-antimicrobial combinations. An increase in susceptibility to ampicillin, ceftazidime, cefepime, aztreonam, ertapenem, and fosfomycin was detected. Growth curves for Psp response mutants showed a decrease in optical density (OD) using sub-MIC concentrations of ceftazidime and aztreonam (ΔpspA and ΔpspB mutants), cefepime (ΔpspB and ΔpspC mutants) and ertapenem (ΔpspB mutant). Time-kill curves were also performed using 1xMIC concentrations of these antimicrobials. For ceftazidime, 2.9 log10 (ΔpspA mutant) and 0.9 log10 (ΔpspB mutant) decreases were observed at 24 and 8 h, respectively. For aztreonam, a decrease of 3.1 log10 (ΔpspA mutant) and 4 log1010 (ΔpspB mutant) was shown after 4-6 h. For cefepime, 4.2 log10 (ΔpspB mutant) and 2.6 log10 (ΔpspC mutant) decreases were observed at 8 and 4 h, respectively. For ertapenem, a decrease of up to 6 log10 (ΔpspB mutant) was observed at 24 h. A deficient Psp envelope stress response increased E. coli susceptibility to beta-lactam agents such as cefepime, ceftazidime, aztreonam and ertapenem. Its role in repairing extensive inner membrane disruptions makes this pathway essential to bacterial survival, so that disbalancing the Psp response could be an appropriate target for sensitization strategies. PB Frontiers YR 2021 FD 2021-04-07 LK http://hdl.handle.net/10668/4481 UL http://hdl.handle.net/10668/4481 LA en NO Recacha E, Fox V, Díaz-Díaz S, García-Duque A, Docobo-Pérez F, Pascual Á, et al. Disbalancing Envelope Stress Responses as a Strategy for Sensitization of Escherichia coli to Antimicrobial Agents. Front Microbiol. 2021 Apr 7;12:653479 DS RISalud RD Apr 19, 2025