Malonate utilization by Pseudomonas aeruginosa affects quorum‐sensing and virulence and leads to formation of mineralized biofilm‐like structures

다국어 초록 (Multilingual Abstract)

Pseudomonas aeruginosa is an opportunistic pathogen that uses malonate among its many carbon sources. We recently reported that, when grown in blood from trauma patients, P. aeruginosa expression of malonate utilization genes was upregulated. In this study, we explored the role of malonate utilization and its contribution to P. aeruginosa virulence. We grew P. aeruginosa strain PA14 in M9 minimal medium containing malonate (MM9) or glycerol (GM9) as a sole carbon source and assessed the effect of the growth on quorum sensing, virulence factors, and antibiotic resistance. Growth of PA14 in MM9, compared to GM9, reduced the production of elastases, rhamnolipids, and pyoverdine; enhanced the production of pyocyanin and catalase; and increased its sensitivity to norfloxacin. Growth in MM9 decreased extracellular levels of N‐acylhomoserine lactone autoinducers, an effect likely associated with increased pH of the culture medium; but had little effect on extracellular levels of PQS. At 18 hr of growth in MM9, PA14 formed biofilm‐like structures or aggregates that were associated with biomineralization, which was related to increased pH of the culture medium. These results suggest that malonate significantly impacts P. aeruginosa pathogenesis by influencing the quorum sensing systems, the production of virulence factors, biofilm formation, and antibiotic resistance.
Pseudomonas aeruginosa utilizes malonate as a carbon source, and upon its growth in blood from trauma patients, P. aeruginosa increased the expression of malonate utilization genes. Here we report that malonate influences the production of several P. aeruginosa virulence factors, with part of this effect through its reversible inactivation of two of the P. aeruginosa cell‐to cell communication molecules. Additionally, after 16 hr of growth, malonate induces P. aeruginosa to form biomineralized aggregates.
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