Antimicrobial resistance is a global health crisis, causing over 1.3 million deaths annually and threatening modern medicine. While antibiotic misuse is a known driver of resistance, non-antibiotic analgesic pharmaceuticals including non-steroidal anti-inflammatory drugs may also play a role. Recent studies have shown that common painkillers that are often co-administered with antimicrobials can inhibit growth and induce bacterial stress responses, potentially enhancing the selection of resistance. Crucially however, these studies have only used lab-adapted strains such as E. coli K-12, not real-world pathogens. Here, we will investigate the response of E. coli pathotypes associated with urinary tract infection, bloodstream infection, neonatal meningitis, and inflammatory bowel disease to various combinations of antimicrobials and non-steroidal anti-inflammatory drugs. Four clinically used antimicrobials with different cellular targets (Trimethoprim/sulfamethoxazole (TMP-SMX), ciprofloxacin, ampicillin and nitrofurantoin) will be tested in combination with acetaminophen, ibuprofen, naproxen, and aspirin. Minimum inhibitory concentration (MIC) assays will be carried out to determine gross alterations in resistance profiles. Growth curves will be constructed at ½ MIC concentrations to examine whether stress induced by analgesic drugs compounds the effect of antimicrobials. Efficiency of bacterial killing will be determined in the presence and absence of analgesic drugs by plating following various periods of incubation. Finally, the effect of analgesic drugs on the resistance evolution will be determined using a lab-based evolution study. The insight gained from these experiments will help inform appropriate usage of pain relieving medications for bacterial infections while minimising the selection of resistance.
