Protective effect of Enterococcus faecalis CECT7121 against Trichinella spiralis infection in mice

Abstract

Trichinellosis is an important parasitic zoonosis produced by the ingestion of raw or undercooked meat infected by Trichinella spiralis larvae. At the present, the pharmacological treatment against Trichinellosis in human is unsuccessful. Therefore, the potential of viable Enterococcus faecalis CECT7121 culture, administered by oral route, in mice against T. spiralis infection was evaluated. Eighteen BALB/C mice were divided in two groups (n=9) as follow: A- Experimental Group: E. faecalis CECT7121 strains were administered daily in a dose of 10 9 UFC/mL in 300 µL for five consecutive days. B-Negative control Group: animals received 300 µL of sterile sodium chloride. On day 5 of treatment, whole mice were infected with 450 T. spiralis larvae. Four mice, from both experimental and control group, were sacrificed on day 6 post infection for assessing the amount of T. spiralis adults from the small intestine. At day 28 post infection the remaining mice from each group were sacrificed and the tongue processed in order to estimate the muscle larval burden in that tissue, used as surrogate marker of the number of larvae per g (LPG) of tissue. The test used for groups statistical comparison was Mann- Whitney. A difference of p< 0.05 was considered significant. The average number of recovered T. spiralis adult worms? from the intestinal content was 105 (± 46) for the treated group and 80 (±42) in control group, resulting in non- significant 24% of reduction (p>0.05). However, the percentage of LPG reductions obtained in tongue tissue after 28 days post- infection increased 62% (p <0.01) in mice treated with E. faecalis CECT7121 as preventive. The quantification of T. spiralis adults in the intestinal content alone was not indicative of presence or absence of protective response when compared with samples obtained from mice tongue tissue. The protective response of E. faecalis CECT7121 against T. spiralis infection will be a contribution to improve the conventional therapeutic against Trichinellosis.