Development and Evaluation of oral pH-responsive microparticles encapsulating inactivated E. Coli to provide immunity in Broiler Poultry to Combat Antibiotic Drug Resistance

Summary 

Avian pathogenic Escherichia coli (E. Coli), an etiologic agent of colibacillosis in poultry, is responsible for great economic losses worldwide with a special focus on middle-income countries. It has been an abusive practice globally to use antibiotics prophylactically to prevent E. coli outbreaks. Antibiotics are routinely added in bulk to poultry diets globally, particularly in LMIC, to prevent various diseases and as growth promotors. The situation is worst in LMIC countries such as Pakistan due to lack of regulatory bodies, awareness, and facilities, the only available vaccine is not in reach of local farmers due to vaccine cost and availability issues. A holistic approach is required to manufacture a vaccine against E.Coli in Pakistan using local strains. In this project, we are aiming to encapsulate killed inactivated local E. Coli strain in novel pH-responsive polymeric carriers to elicit an immune response in the chick gut to provide maximum protection to birds. We will conduct vaccination and challenge studies and evaluate the immune response induced by our prototype vaccine. This vaccine will prevent the release of antigens in the environment. The project will be led by an initial female researcher from LMIC and Pakistani mid-career researchers, a UK academic scientist, and a veterinary pharmaceutical industry from LMIC (Pakistan). These all will bring together a unique combination of expertise in Pharmaceutics, immunology, Poultry, and veterinary sciences to advance a novel approach to poultry vaccination with a special focus to control E. Coli outbreak particularly in low and middle-income countries.

Project Outcomes

Chicken is one of the most popular and consumed sources of protein in the world. Good poultry farming ensures a healthy supply of chicken. However, poultry is susceptible to many diseases such as E. coli and other bacterial outbreaks. Poultry farmers rely heavily on using antibiotics to combat such problems, which is an unsustainable practice, and also poses the continuation of the global AMR problem.In this project, an oral vaccine against E. coli was developed based on inactivated bacteria encapsulated in polymeric microparticles.  The latter can be mixed with feed or drinking water. This will release maximum antigen to the chick gut and boost local immunity of the gut results in increased protection from the infection. To evaluate the vaccine’s efficacy, groups of chicks were immunized, by injection or orally (via feed or drinking water), and then exposed to E.Coli.  We found survival was higher for chicks immunized orally than those immunized by injection or controlled non-vaccinated chicks.  Our findings confirm the potential of oral vaccines to prevent infections in poultry and reduce antibiotic use, the risk of worsening antimicrobial resistance, and economic loss to farmers.