A synthetic peptide sensitizes multi-drug resistant Pseudomonas aeruginosa to antibiotics for more than two hours and permeabilizes its envelope for twenty hours

Table 3 Post-Antibiotic Effect (PAE) and Score of Post-Antibiotic Effect-associated Permeabilization (S-PAEP) induced by antibiotics on Ps4

Agent used as pre-treatment^a	MIC/MBC (μg/mL)	Final concentration (μg/mL)	PAE^b (h)	PAEP^c (h)	S_nov-PAEP^d (h)
Agent used as pre-treatment^a	MIC/MBC (μg/mL)	Final concentration (μg/mL)	PAE^b (h)	PAEP^c (h)	0	1	2
GEN	2/2	4	0.75 + 0,01	0	< 0.25	< 0.25	< 0.25
CIP	2/2	4	1.5 + 0,06	0	< 0.25	< 0.25	< 0.25
IPM	2/2	4	0	0	< 0.25	< 0.25	< 0.25
PMB	1/1	2	0.1 + 0,02	2–3	3.2 + 0.06	2.7 + 0.05	1.1 + 0.03

^a GEN, gentamicin; CIP, ciprofloxacin; IPM, imipenem; PMB, polymyxin B
^b Post-antibiotic effect assessed by turdidimetry (Bioscreen)
^c Duration of Post-Antibiotic Effect-associated Permeabilization. PAEs y S-PAEPs values are the average of two independent experiments performed in triplicate. Differences were analyzed by Kruskal–Wallis test followed by Mann–Whitney’s U test
^d Score of Post-Antibiotic Effect-associated Permeabilization. Delay in h caused by exposure to a sub-MIC concentration of novobiocin (1/8 x MIC) added at the indicated time (0 h, 1 h, 2 h) after the beginning of growth in peptide-free medium. S-PAEP was assessed by turdidimetry (Bioscreen)

ISSN: 1423-0127