Herbal Oils and Probiotic Efficacy in Rabbits Challenged with Multidrug-Resistant Escherichia coli

Colibacillosis is a common infectious bacterial disease that can cause enteritis and high mortality in young rabbits, threatening the breeding industry. This work was performed to express some virulence-determining genes and antimicrobial resistance patterns of isolated E. coli and to study the efficacy of herbal oils and/or probiotic on reducing E. coli infection in rabbits. Vaginal swabs and semen samples were collected from rabbits with reproductive problems (farm 1) and anal swabs were collected from rabbits with diarrhea (farm 2) in Ismailia Governorate, Egypt. Samples were subjected for bacterial identification, antibiogram-testing and molecular monitoring of iss and eaeA virulence genes. An experiment was performed in which 54 weaned California rabbits were divided into 6 equal groups, negative control group (G1), non-infected treated with probiotic and both fennel and moringa oils (G2), Infected and treated with probiotic, fennel and moringa oils (G3), treated with probiotic only (G4), treated with colistin sulfate (G5) and Positive control (G6). Infected groups (G3, G4, G5 and G6) were challenged orally with E. coli (1x107 CFU). The detection of E. coli was 15.3% (2/13) and 62.5% (10/16) in farm (1) and (2) respectively. The isolated E. coli was multidrug-resistant (MDR), carrying virulence genes iss and eaeA, with prevalence of 100% (12/12) and 50% (6 /12) respectively. Clinical symptoms were prominent in the experiment E. coli infected untreated group (6), with the least evidence in group (5). The E. coli colony counts were significantly higher in group (6) while rabbits in group (3) had significantly higher body weights compared to infected groups. Thus, we concluded that, the use of two herbal oils and probiotics were able to reduce mortality rates, clinical signs, and the total E. coli count in experimentally infected rabbits.