Repurposing the Anticancer Drug Cisplatin for Antibacterial Therapy: Evaluating Its Efficacy Against Pseudomonas aeruginosa Infections.

Background: The rising global threat of antimicrobial resistance, particularly among multidrug-resistant pathogens like Pseudomonas aeruginosa, has prompted research into repurposing existing drugs with established safety profiles. Cisplatin, a well-known anticancer agent, has shown preliminary antimicrobial activity but its efficacy against P. aeruginosa has not been thoroughly explored. This study aims to evaluate the antimicrobial potential of cisplatin against clinical strains of P. aeruginosa by determining the minimum inhibitory concentration (MIC).

Methodology: This study assessed whether cisplatin could serve as a novel therapeutic option for treating infections caused by P. aeruginosa via broth microdilution assay, especially as the pathogen shows increasing resistance to last-resort antibiotics such as meropenem, colistin, and tigecycline. Findings from this research could contribute to expanding the arsenal of treatments for resistant P. aeruginosa infections.

Results: The study found that 54.9% of isolates had an MIC of 16 µg/mL, 26.8% had 32 µg/mL, 12.7% had 64 µg/mL, and 5.6% had 8 µg/mL. While cisplatin demonstrated antibacterial activity, no statistically significant difference (p = 0.089) was observed between sensitive and resistant strains. A key limitation of this study is the small number of both resistant and sensitive strains, which limits statistical power. Increasing the sample size in future studies will allow for a more robust assessment of cisplatin's efficacy and validate the observed MIC similarities. Additionally, further studies including resistance assays, time-kill kinetics, and in vivo models are needed to explore its bactericidal potential and efficacy in combination with β-lactams.

Conclusion: Although cisplatin exhibited activity against P. aeruginosa, its clinical potential remains uncertain, and further investigation is necessary to optimize its use and overcome resistance.