Human probiotic bacteria attenuate Pseudomonas aeruginosa biofilm and virulence by quorum-sensing inhibition

Abstract

This work investigated chloroform extracts from culture supernatants of two human probiotic bacteria, Lactobacillus casei CRL 431 and Lactobacillus acidophilus CRL 730 for the production of virulence factors and quorum sensing (QS) interference against three Pseudomonas aeruginosa strains. Both extracts inhibited biofilm biomass (up to 50%), biofilm metabolic activity (up to 39%), the production of the enzyme elastase (up to 63%) and pyocyanin (up to 77%), and decreased QS, without presenting any antibacterial acgivity. In addition, the chloroform extracts of both strains disrupted preformed biofilms of the three strains of P. aeruginosa analyzed (up to 40%). GC-MS analysis revealed that the major compounds detected in the bioactive extracts were four diketopiperazines. This study suggests that the metabolites of L. casei and L. acidophilus could be a promising alternative to combat the pathogenicity of P. aeruginosa.

Keywords:

• Biofilm
• lactobacilli
• elastase
• pyocyanin
• diketopiperazines

Data availability

The data used to support the findings of this study are included in the article.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors acknowledge financial support from the SCAIT-UNT (PIUNT D26/638-1), the Agencia Nacional de Promoción Científica y Técnica ANPCyT (PICT 02071 and 02514), and The Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET (PIP 662). The authors also acknowledge the authorization granted to use the probiotic strains CRL 431 and CRL 730 from the Culture Collection of CERELA-CONICET, Tucumán, Argentina.