Abstract
Exposure of the Gram-negative pathogen Pseudomonas aeruginosa to sub-inhibitory concentrations of antibiotics increases formation of biofilms. We exploited this phenotype to identify molecules with potential antimicrobial activity in a biofilm-based high-throughput screen. The anti-inflammatory compound BAY 11-7082 induced dose-dependent biofilm stimulation, indicative of antibacterial activity. We confirmed that BAY 11-7082 inhibits growth of P. aeruginosa and other priority pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). We synthesized 27 structural analogues, including a series based on the related scaffold 3-(phenylsulfonyl)-2-pyrazinecarbonitrile (PSPC), 10 of which displayed increased anti-Staphylococcal activity. Because the parent molecule inhibits the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome, we measured the ability of select analogues to reduce IL-1β production in mammalian macrophages, identifying minor differences in the structure-activity relationship for the anti-inflammatory and antibacterial properties of this scaffold. Although we could evolve stably resistant MRSA mutants with cross resistance to BAY 11-7082 and PSPC, their lack of shared mutations suggested that the two molecules could have multiple targets. Finally, we showed that BAY 11-7082 and its analogues potentiate the activity of penicillin G against MRSA, suggesting that this scaffold may serve as an interesting starting point for the development of antibiotic adjuvants.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
The title was revised to remove a typo.
Abbreviations Used
- ARP
- Antibiotic Resistance Platform;
- CCCP
- carbonyl cyanide m-chlorophenyl hydrazine;
- DiSC3(5)
- 3,3’-dipropylthiadicarbocyanine iodide;
- FICI
- fractional inhibitory concentration index;
- LB
- lysogeny broth;
- MHA
- Mueller-Hinton agar;
- MHB
- Mueller-Hinton broth;
- PMF
- proton motive force;
- PSPC
- 3-(phenylsulfonyl)-2-pyrazinecarbonitrile;
- PTP
- protein tyrosine phosphatase;
- TAT
- twin arginine translocase