Coffee breaks the journey of pseudomonads: a pause for a reflection

Pseudomonas aeruginosa is a critical pathogen according to the WHO list of priority bacteria. It is nutritionally versatile and expresses different virulence factors, which contribute to its resilience to environmental stresses as well as its tolerance and resistance to antimicrobials. These demands the search for strategies to combat microbial growth, a scenario in which natural bioactive compounds are being widely investigated. In this work, the activity of caffeine on the motility and biofilm adhesion to glass and plastic surfaces were tested with two strains of P. aeruginosa: TGC-04 (wild type) and ATCC 9027 (clinical strain). Both strains adhered weakly to the tested surfaces. The clinical strain showed a reduction in adhesion to plastic and glass of 46.9 and 65.0%, respectively, while the wild type strain was unaffected by caffeine (1024 μg/mL). In addition, there was inhibition in swarming and twitching motilities, and swimming motility was not affected. The results suggest that the strain origin may be an important factor in the susceptibility of P. aeruginosa to caffeine.