By Sharon Atieno
Despite poultry farming being a strategic sector in Tunisia, accounting for 33% of animal production and 59% of meat consumed in the country, antibiotic misuse continues to be a major challenge.
Of 76 countries ranked in the 2018 report titled Global Increase and Geographic Convergence in Antibiotic Consumption 2000-2015, Tunisia was the second among the low and middle-income countries with the highest consumption rates.
Tunisian researchers from the University of Tunis El Manar in partnership with others from the University of Laval in Canada, University of La Rioja in Spain and Museum National d’Histoire Naturelle in France, are working on developing a feed supplement from bacteriocins (antibacterial substances naturally produced by several bacteria) to help reduce the use of antibiotics in poultry operations.
Unlike antibiotics, bacteriocins are able to target very specifically pathogens resistant to multiple antibiotics without altering the gut-beneficial bacteria (microbiota), which play a major role in the host’s health.
According to Prof. Karim Ben Slama, Professor at the Higher Institute of Applied Biological Sciences of Tunis and Project Leader in Tunisia, the bacteriocins can be added to feed as natural components to limit the large-scale use of antibiotics in poultry but not totally replacing them. “Antibiotics can still be used in therapy or treatment of other bacterial illness,” he added.
Already, the capacity of bacteriocins to kill or limit the growth of certain bacteria has been widely demonstrated in several dairy, meat, and plant products.
The AviBiocin project was started in 2019 with the overarching goal of limiting the spread of antimicrobial resistance (AMR) in Tunisian poultry operations.
According to the World Health Organization, AMR, fueled by misuse of antibiotics among other factors, is a global public health threat responsible for about 700,000 deaths annually. If no action is taken, the number is estimated to rise to 10 million deaths annually by 2050. Thus, calling for the need to develop new alternatives that can be used as a replacement or in combination with antibiotics for greater efficacy.
The project objectives included identifying the prevalence of antibiotic resistance in poultry farms in the country and finding out if intestinal bacteriocins are capable of inhibiting multi-resistant pathogenic bacterial strains isolated from poultry in Tunisia.
The researchers also wanted to find out how these bacteriocins interact in the gastrointestinal tract of chickens and their impacts on the chicken’s gut microbiota.
The other objective is to find out the impact of this natural approach on the growth and microbiological quality of carcasses.
The researchers have been able to identify bacterial strains from samples collected from poultry farms across the country including E. coli and Enterococcus.
“These bacteria are present in the human and animal gut microbiota. Actually, they are the most frequent pathogens implicated in nosocomial infections worldwide,” said Prof. Ben Slama.
“Enterococci and E. coli are characterized by their innate resistance to a broad spectrum of antimicrobials and their capacity to acquire and transfer a lot of antibiotic resistance genes via mobile genetic elements to and from other pathogenic bacteria.”
The AviBiocin project aims to characterize antibiotic resistance profiles and the genetic relatedness between bacteria collected from poultry farms in Tunisia.
“These natural antimicrobial peptides have demonstrated promising activity to kill or inhibit pathogens and antibiotic-resistant pathogens during in vitro assays. Their results must be extrapolated by the use of animal models in vivo assays in the treatment and prevention of microbial infections,” Prof. Ben Slama said.
The researchers have been able to isolate bacteria that produce bacteriocins and characterize their provision of these bacteriocins in the laboratory.
Prof. Ben Slama noted that together with their partners at the University of Laval, they have been able to characterize and prepare a bacteriocin that is ready for testing in poultry, outside the lab.
Microcin J25, the bacteriocin prepared for testing, has demonstrated high performance against multi-resistant germs in the laboratory, especially against gram-negative bacteria such as Salmonella and some E. coli among others which cause problems for both the animals and consumers.
He noted that they have partnered with one of Tunisia’s biggest poultry farms, Poulina Group Holding, which has an experimental farm where the testing is set to be conducted in February or March 2023.
If the experiment proves successful as it did in the laboratory, Prof. Ben Slama is optimistic that it will be a game changer in reducing rates of antibiotic misuse by farmers in both middle and low-income countries.
Additionally, he notes that the findings can be upscaled not only in the poultry industry but other animal production sectors to curb AMR.
AviBiocin is part of the larger Innovative Veterinary Solutions for Antimicrobial Resistance (InnoVet-AMR), a CAN$ 27.9 million initiative focusing on reducing the misuse of antibiotics in the poultry, swine and aquaculture sectors in low and middle-income countries.
Through a partnership between the International Development Research Centre (IDRC) and the United Kingdom (UK) government’s Global AMR Innovation Fund (GAMRIF), InnoVet-AMR supports 11 projects across eight countries worldwide. These include Brazil, Cuba, Tunisia, Kenya, Vietnam, Thailand, Pakistan and Malaysia.
Other poultry projects being funded include developing a sustainable nanoparticle-based vaccine solution for broilers and layers against E. coli in Brazil, using phages for the replacement of antibiotics and reduction of drug-resistant non-typhoidal Salmonella in poultry farms in Kenya, and development and commercialization of antibiotic alternatives: phages and nutraceuticals for Pakistan poultry production.