Evaluating The Effectiveness of A Non-Locally Developed Commercial Phage Cocktail on Kenyan Pseudomonas aeruginosa Isolates

Objectives: The use of bacteriophages (phages) as an alternative treatment for multidrug-resistant bacteria has recently gained popularity. Phage cocktails have been proposed for broad-spectrum therapeutic effects against such resistant bacteria. However, the effectiveness of non-locally formulated phage cocktails for therapy on Kenyan isolates has yet to be evaluated and is a subject of investigation. This study aimed to determine the in vitro effectiveness of a non-locally made commercial pyophage cocktail on clinical Pseudomonas aeruginosa isolates from Kenya. Methodology: Forty-nine P. aeruginosa isolates from Kenya were subjected to a pyophage cocktail for efficacy studies using direct spot test (DST) and efficiency of plating (EOP). Results: The success rate of the cocktail was observed on 16.3% (8/49) isolates only and ineffective on 83.7% (41/49) isolates. Six of the eight isolates that showed cross-reactivity from DST had complete lysis with a faintly hazy background. Five of these six isolates resulted in successful and high phage progeny production in plaquing efficiency (EOP ≥ 0.5). Conclusion: Non-locally made commercial pyophage cocktail was ineffective against the 83.7% endemic clinical strains of the Kenyan P. aeruginosa isolates, demonstrating the importance of locally derived phage cocktails against endemic and multidrug-resistant isolates. J Microbiol Infect Dis 2023; 12(4):25-30.