Silica vesicles increase stability of Salmonella-specific phages isolated from chicken in environments mimicking the gastrointestinal tract

Non-typhoidal Salmonella (NTS) enterica serovar Enteritidis is one of the major causes of foodborne infections worldwide. This NTS serovar is mainly transmitted to humans through poultry products. Bacteriophages (phages) are a promising alternative to antibiotics to reduce NTS incidences in poultry farms. The ability to survive the harsh environment encountered in the chicken gastrointestinal tract (GIT), such as low pH, high temperature and enzymatic digestion, can be valuable in selecting phages with high therapeutic potential. In this study, we characterized 13 newly isolated Kenyan S. Enteritidis-specific phages for their ability to survive in pH-adjusted media, different temperatures, and simulated gastric and intestinal fluids (SGF and SIF, respectively). Furthermore, we evaluated the possibility of using silica vesicles (SV) to increase the stability of these phages in these environments. All phages were relatively stable from pH 4 to 12 and from 25℃ to 42℃ following 12 hours of incubation. At pH 3, phages lost up to 3 logs in viral titres after three hours of incubation. They remained more stable at pH 9, with phage titres 2 logs higher than at pH 3. In SGF, they were stable for 20 minutes; afterwards, they started losing their viability up to 5 logs, while they were relatively stable in SIF for up to two hours. Moreover, significant differences were observed among the different phages in surviving these environments. Encapsulating phages with SV demonstrated a slow but long rate of phage release upon adsorption for 96 hours. Preliminary data indicate that SV 140 C18 can protect phages longer than other silica vesicles tested. In contrast, free phages in SGF had an average reduction of 7 logs PFU/ml after 60 minutes of incubation. These data suggest that a number of these phages can potentially survive through the chicken GIT and that SV can be an ideal technology to prolong the stability of phages in acidic environments

Capacitating One Health in Eastern and Southern Africa

The world is facing unprecedented, inter-connected threats to the health of people, animals and the environment. Threats to health security originating from animals and ecosystems can best prevented and managed by One Health (OH) which recognizes the interconnection of people, animals, plants, and their shared environment. But attaining the OH dividend requires greater operationalization of OH science and harnessing the power of youth to solve the problems of the present and future. In line with this approach, this project aims to enhance national and sub-regional cross-sectoral collaboration between government entities with OH mandates and OH stakeholders across society, to equip educational and research institutes to train the next generation One Health workforce, and to increase the capacity of government and non-governmental stakeholders to identify and deliver OH solutions to key problems. To conceptualize the above objectives, we conducted an expert integrative review to identify OH capacity potential and gaps in eastern and southern Africa, to develop a four-year, eleven-country project to translate OH science to development impact. We identified neglected zoonoses, emerging zoonoses, food safety and livestock associated antimicrobial resistance as key OH domains, with soil health subsidiary. Multi-criteria processes identified 11 priority countries (Botswana, Ethiopia, Kenya, Malawi, Mozambique, Namibia, Rwanda, Tanzania, Uganda, Zambia, and Zimbabwe, of which four are deep dive) and four support areas (observatory, platforms, future workforce and field solutions). A consortium was developed of research and research translation institutes (three Africa-based) linked to multipliers in priority countries. Future OH capacity will be enhanced through strengthening educational institutions to deliver recognised OH courses. Delivery of solutions for a specific OH issue is planned for Ethiopia, Kenya, Mozambique and Zimbabwe, with the approach then used as a model for OH delivery. This initiative will ensure government entities capacitated in the development of evidence based One Health strategies and policies, education institutes strengthened in building OH capacity of the present and future workforce, and research institutes capacitated in identification, development, adoption and delivery of One Health solutions

International Livestock Research Institute One Health initiatives in Africa: Concepts and applications

The frequency and severity of zoonotic diseases, such as the current COVID pandemic, is increasing as humans encroach on wildlife habitats, and as food production systems intensify. The One Health approach (OH) offers the best chance for solving these challenges by overcoming institutional barriers by cross-sectoral collaboration and providing stronger evidence on effective, economical, and acceptable risk management. The International Livestock Research Institute (ILRI) has various ongoing OH initiatives in collaboration with national and international partners focusing on foodborne diseases, zoonoses, emerging infectious diseases and antimicrobial resistance. The CGIAR One Health initiative (Protecting Human Health Through a One Health Approach), aims to demonstrate how One Health principles and tools integrated into food systems can help reduce and contain zoonotic disease outbreaks, improve food, and water safety, and reduce antimicrobial resistance, benefitting human, animal, and environmental health. The One Health Research, Education and Outreach Centre in Africa (OHRECA) aims to improve the health of humans, animals, and ecosystems through capacity building, strengthening of local, regional and global networks and provision of evidence-based policy advice on One Health in sub-Saharan Africa. One of the capacity-building activities is the partnership with Lilongwe University of Agriculture and Natural Resources (LUANAR) and includes co-supervision and research funding support to final year veterinary students. The CGIAR Antimicrobial Resistance Hub uses a OH approach to support efforts in low- and middle-income countries to mitigate risks of agriculture-associated antimicrobial resistance. The Hub supports the development of cost-effective interventions that are locally relevant and applicable. The CGIAR COVID 19 Hub provides a coordinated research response to the global pandemic threatening health systems worldwide, along with posing serious risks to food security; local businesses and national economies; and hard-fought progress by stakeholders at all levels towards the Sustainable Development Goals. The BUILD Uganda project supports existing livestock health initiatives by helping to scale solutions through a collaborative effort in research, extension and partnerships in Uganda. The Capacitating One Health in Eastern and Southern Africa (COHESA) initiative was set up to Increase the relevance of One Health research and policies in eastern and southern Africa, by enhancing national and sub-regional cross-sectoral collaboration, equipping educational and research institutes to train the next generation One Health workforce, and increasing the capacity to identify and deliver One Health solutions to key problems. While ILRI OH initiatives are promising and posed for success, challenges have been observed in mainstreaming ecosystem health and operationalizing OH. These are being addressed through strengthening existing research collaborations, engaging with stakeholders in food systems at all levels, and building new partnerships with ecosystem actors such as the United Nations Environment Programme

Phages for Africa: The potential benefit and challenges of phage therapy for the livestock sector in sub-Saharan Africa

One of the world’s fastest-growing human populations is in Sub-Saharan Africa (SSA), accounting for more than 950 million people, which is approximately 13% of the global population. Livestock farming is vital to SSA as a source of food supply, employment, and income. With this population increase, meeting this demand and the choice for a greater income and dietary options come at a cost and lead to the spread of zoonotic diseases to humans. To control these diseases, farmers have opted to rely heavily on antibiotics more often to prevent disease than for treatment. The constant use of antibiotics causes a selective pressure to build resistant bacteria resulting in the emergence and spread of multi-drug resistant (MDR) organisms in the environment. This necessitates the use of alternatives such as bacteriophages in curbing zoonotic pathogens. This review covers the underlying problems of antibiotic use and resistance associated with livestock farming in SSA, bacteriophages as a suitable alternative, what attributes contribute to making bacteriophages potentially valuable for SSA and recent research on bacteriophages in Africa. Furthermore, other topics discussed include the creation of phage biobanks and the challenges facing this kind of advancement, and the regulatory aspects of phage development in SSA with a focus on Kenya

Gender-responsive design of bacteriophage products to enhance adoption by chicken keepers in Kenya

Women and men keeping chickens in Kenya aspire to have a source of income, feed their families healthy food, and grow their businesses. Managing animal diseases and minimizing input costs enable their success. This study uses qualitative methods to recommend design opportunities for a veterinary product under development in Kenya that contains bacteriophages (phages) that target pathogenic Salmonella strains responsible for fowl typhoid, salmonellosis, and pullorum in chickens and foodborne illness in people. Our findings revealed the interplay between gender and two production systems: free-range and semi-intensive. Chicken keepers in both systems could benefit from phages combined with the orally administered Newcastle disease vaccine, one of the most commonly used preventive veterinary interventions, or phages as a treatment for fowl typhoid. Oral administration is less labor intensive, with greater benefits for women who have less control over family labor and reported doing more care tasks themselves. Men in free-range systems usually pay for veterinary inputs. In semi-intensive production systems, a phage-based product used prophylactically could be an alternative to expensive, intramuscular fowl typhoid vaccines. Keeping layers was common for women in semi-intensive systems, as they are more economically impacted by reduced laying caused by bacterial diseases. Awareness of zoonoses was low, but men and women were concerned about the negative health effects of drug residues in meat and eggs. Therefore, highlighting the lack of a withdrawal period for a phage product may appeal to customers. Antibiotics are used to both treat and prevent diseases, and phage products will need to do both to compete in the Kenyan market. These findings guide the ongoing design of a phage-based product with the goal of introducing a new veterinary product that meets the diverse needs of chicken keepers in Africa and serves as an alternative or complement to antibiotics

Salmonella Enteritidis bacteriophages isolated from Kenyan poultry farms demonstrate time-dependent stability in environments mimicking the chicken gastrointestinal tract

Multi-drug resistant (MDR) Salmonella enterica Enteritidis is one of the major causes of foodborne illnesses worldwide. This non-typhoidal Salmonella (NTS) serovar is mainly transmitted to humans through poultry products. Bacteriophages (phages) offer an alternative to antibiotics for reducing the incidence of MDR NTS in poultry farms. Phages that survive the harsh environment of the chicken gastrointestinal tract (cGIT), which have low pH, high temperatures, and several enzymes, may have a higher therapeutic or prophylactic potential. In this study, we analysed the stability of 10 different S. Enteritidis phages isolated from Kenyan poultry farms in different pH-adjusted media, incubation temperatures, as well as simulated gastric and intestinal fluids (SGF and SIF, respectively). Furthermore, their ability to persist in water sources available in Kenya, including river, borehole, rain and tap water, was assessed. All phages were relatively stable for 12 h at pHs ranging from 5 to 9 and at temperatures ranging from 25 °C to 42 °C. At pH 3, a loss in viral titre of up to three logs was observed after 3 h of incubation. In SGF, phages were stable for 20 min, after which they started losing infectivity. Phages were relatively stable in SIF for up to 2 h. The efficacy of phages to control Salmonella growth was highly reduced in pH 2- and pH 3-adjusted media and in SGF at pH 2.5, but less affected in SIF at pH 8. River water had the most significant detrimental effect on phages, while the other tested waters had a limited impact on the phages. Our data suggest that these phages may be administered to chickens through drinking water and may survive cGIT to prevent salmonellosis in poultry