Diaz-Nunez, Jose Luis; Perez-Lopez, Macrina; Espinosa, Norma; Campos-Hernandez, Nayelli; Garcia-Contreras, Rodolfo; Diaz-Guerrero, Miguel; Cortes-Lopez, Humberto; Vazquez-Sanchez, Monserrat; Quezada, Hector; Martinez-Vazquez, Mariano; Soto-Hernandez, Ramon Marcos; Burgos-Hernandez, Mireya; Gonzalez-Pedrajo, Bertha; Castillo-Juarez, Israel (2021)

ANTI-VIRULENCE PROPERTIES OF PLANT SPECIES: CORRELATION BETWEEN IN VITRO ACTIVITY AND EFFICACY IN A MURINE MODEL OF BACTERIAL INFECTION

Microorganisms 9(12):

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Several plant extracts exhibit anti-virulence properties due to the interruption of bacterial quorum sensing (QS). However, studies on their effects at the preclinical level are scarce. Here, we used a murine model of abscess/necrosis induced by to evaluate the anti-pathogenic efficacy of 24 plant extracts at a sub-inhibitory concentration. We analyzed their ability to inhibit QS-regulated virulence factors such as swarming, pyocyanin production, and secretion of the ExoU toxin via the type III secretion system (T3SS). Five of the seven extracts with the best anti-pathogenic activity reduced ExoU secretion, and the extracts of and were identified as the most active. Therefore, the abscess/necrosis model allows identification of plant extracts that have the capacity to reduce pathogenicity of . Furthermore, we evaluated the activity of the plant extracts on . T3SS (Δ) and QS (Δ) mutant strains were assessed in both the abscess/necrosis and sepsis models. Only the Δ strain had lower pathogenicity in the animal models, although no activity of plant extracts was observed. These results demonstrate differences between the anti-virulence activity recorded in vitro and pathogenicity in vivo and between the roles of QS and T3S systems as virulence determinants.