Antinematodic effect of Enterococcus faecalis CECT7121 using Trichinella spiralis as a model of nematode infection in mice

Nematode infections affect a significant percentage of the human population worldwide, especially in developing countries. There are a small number of drugs available to treat these infections, with variable outcomes. Therefore, the potential use of probiotics to help control parasitic infections has emerged as a suitable option. The main goal of this work was to assess the antinematodic effect of the probiotic Enterococcus faecalis CECT7121 (EFCECT7121) in vitro and in vivo, using Trichinella spiralis as a nematode model of infection. The in vitro assay showed a reduction in T. spiralis larvae viability of 31.6% when compared with the control group (6.3%) after 48 h incubation with EFCECT7121. Nevertheless, the isolated antimicrobial peptide AP7121 when inoculated at different concentrations did not reveal any larvicidal effect. Different EFCECT7121 treatment schemes in mice were evaluated, and the reduction of the enteral and parenteral burden of T. spiralis was determined. In addition, the protective effect of EFCECT7121 combined with the conventional anthelmintic albendazole (ABZ, 5 mg/kg) was also assessed. The oral administration of EFCECT7121 previous T. spiralis infection produced a reduction in the larvae per gram (LPG) of mice muscle tissue ranging from 32.8 to 47.9% on the 28th day post-infection. ABZ alone and the combination EFCECT7121 + ABZ produced a reduction of the LPG of muscle tissue of 62 and 60.7%, respectively. Results obtained in the current work support the hypothesis that probiotics such as EFCECT7121 have an antinematodic effect, and their combination with conventional anthelmintic drugs may result useful for improving clinical and parasitological outcomes.

Concomitant Therapy of Inactivated Enterococcus faecalis CECT7121 with Fluoroquinolones in a Salmonella Enteritidis Murine Sepsis Model

Optimization of existing antimicrobial therapies is a strategy proposed for extending antimicrobial activity and delaying resistance development. This study aimed to assess the effect of inactivated E. faecalis CECT7121 (I-EFCECT7121) in a combined therapy with Enrofloxacin or Ciprofloxacin in a S. Enteritidis murine sepsis model. Firstly, dose titration studies were performed to set up: (a) Salmonella Enteritidis (SE) Lethal dose 99 (LD99) and (b) safety of I-EFCECT7121 (c) I-EFCECT7121 dosage scheme. Then, I-EFCECT7121 in combined therapy with 4 doses (5 mg/kg) per 12 h of CFX and EFX in an LD99 BALB/c infection, were evaluated. Survival rate was monitored for 20 days in order to estimate the treatment success. The efficacy of both drugs was improved by combining them with the inactivated bacteria. However, only a significant increase (p < 0.05) was observed after I-EFCECT7121 and CFX combined treatment (40% of survival rate). By contrast, each drug alone achieved a 10% of survival rate. These outcomes showed a potential therapeutic synergism when I-EFCECT7121 was concomitantly given with ciprofloxacin.