Therapeutic Efficacy of Phage P-IZ SAE-01E2 against Abortion Caused by Salmonella enterica Serovar Abortusequi in Mice

摘要

Salmonella enterica subsp. enterica serovar Abortusequi is a frequently reported pathogen causing abortion in mares. In this study, the preventive and therapeutic effects of phage P-IZ SAE-01E2 against S. Abortusequi in a mouse model of abortion were investigated. Phage P(IZ )SAE-01E2 was stable at different temperatures (4 to 70 degrees C) and pH values (pH 4 to 10) and could lyse the majority of the Salmonella serogroup O:4 and O:9 strains tested (25/28). There was no lysogeny-related, toxin, or antibiotic resistance-related gene in the genome of P-IZ SAE-01E2. All of these characteristics indicate that P-IZ SAE-01E2 has the potential for use in phage therapy. In in vivo experiments, 2 x 10(3) CFU/mouse of S. Abortusequi ATCC 9842 was sufficient to lead to murine abortion (gestational day 14.5) within 48 h. A single intraperitoneal inoculation of P-IZ SAE-01E2 (10(8) PFU/mouse, multiplicity of infection = 10(5)) 1 h before or after S. Abortusequi challenge provided effective protection to all pregnant mice (10/10). After 24 h of treatment with phage P-IZ SAE-01E2, the bacterial loads in both the placenta and the uterus of the infected mice were significantly decreased (10(8) CFU/g). In addition, the levels of inflammatory cytokines in the placenta and blood of the mice in the phage administration groups were significantly reduced (P < 0.05) compared to those in the placenta and blood of the mice in the control group. Altogether, these findings indicate that P-IZ SAE01E2 shows the potential to block abortions induced by S. Abortusequi in vivo.