Based on the published data, several bacteria have been found to be susceptible to aspirin (acetylsalicylic acid) or its metabolite salicylic acid:
## Gram-positive bacteria
– *Staphylococcus aureus*: Aspirin inhibited the growth of S. aureus and enhanced its susceptibility to antimicrobial agents[2][3].
– *Staphylococcus epidermidis*: Biofilm production was reduced by 50% at high concentrations of aspirin (5 mM)[7].
– *Streptococcus pyogenes*: One strain showed a minimum inhibitory concentration (MIC) of aspirin at 0.04 mg/mL[1].
– *Listeria monocytogenes*: Aspirin reduced bacterial burden in infected mice[7].
## Gram-negative bacteria
– *Helicobacter pylori*: Aspirin inhibited the growth of H. pylori in a dose-dependent manner[2].
– *Pseudomonas aeruginosa*: Biofilm production was reduced by 50% at high concentrations of aspirin (32 mM)[7].
– *Escherichia coli*: Aspirin showed some antibacterial activity, though less than against Gram-positive bacteria[7].
– *Klebsiella pneumoniae*: Aspirin partially or totally reverted resistance to colistin in some strains[7].
## Other microorganisms
– *Candida albicans*: Aspirin showed significant anti-biofilm activity at concentrations between 50 and 200 μM[8].
– *Candida parapsilosis*: Aspirin inhibited biofilm formation[8].
– *Fusobacterium nucleatum*: Aspirin showed antibacterial activity against this oncomicrobe[9].
It’s important to note that the susceptibility of bacteria to aspirin often requires higher concentrations than typically achieved in plasma at standard therapeutic doses. The antibacterial effects of aspirin are generally more pronounced against Gram-positive bacteria compared to Gram-negative bacteria[7]. Additionally, aspirin’s effects on bacterial susceptibility to antibiotics can be complex, potentially enhancing or compromising antibiotic effectiveness depending on the specific bacteria and antibiotic combination[4][10].
Citations:
[1] https://www.biorxiv.org/content/10.1101/2021.05.21.445232v1.full
[2] https://gut.bmj.com/content/52/4/490.abstract
[3] https://geiselmed.dartmouth.edu/news/2003_h2/16jul2003_aspirin.shtml
[4] https://www.tandfonline.com/doi/pdf/10.1080/14728222.2018.1527314
[5] https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2019.00217/full
[6] https://www.sciencedirect.com/science/article/abs/pii/S135727250000042X
[7] https://pmc.ncbi.nlm.nih.gov/articles/PMC8868581/
[8] https://www.nature.com/articles/s41598-020-72731-y
[9] https://www.cancergrandchallenges.org/news/caitlin-brennan-discusses-the-microbiome-and-aspirins-potential-in-personalised-prevention
[10] https://www.tandfonline.com/doi/full/10.1080/14728222.2018.1527314