Dickeya zeae WH1 as sensor for cost-effective detection of pyocyanin produced by Pseudomonas aeruginosa.

Pyocyanin is a crucial virulence factor uniquely secreted by Pseudomonas aeruginosa. Hence, the rapid and selective detection of pyocyanin can reveal essential information about the pathogenesis of diseases caused by clinical isolates. Herein, we found that P. aeruginosa PAO1 exhibited remarkable antagonistic activity against Dickeya zeae WH1. Subsequently, its active compounds were purified by preparative high-performance liquid chromatography and HPLC, and anti-WH1 activity was determined by performing the minimum inhibitory concentration (MIC) assay. Only one active compound, pyocyanin, was obtained. Importantly, the linear quantification of pyocyanin to the biomass (OD600) of WH1 showed an R² value of 0.9908 ranging from 0.195 to 6.25 µg/mL, and pyocyanin concentration was accurately determined using this curve when P. aeruginosa was cultured in high-, medium-, and low-pyocyanin-producing media. Therefore, using D. zeae WH1 as a sensor for detecting pyocyanin and high-pyocyanin-producing isolates by high-throughput screening is a cost-effective and simple method.