Multidrug-resistant bacteria are increasingly present in humans and animals and pose a serious health risk. The use of antibacterial drugs in broiler production is under scrutiny because it causes a selective pressure that selects for drug-resistant bacteria and promotes the spread of multidrug-resistance. Thus, a reduction of the use of antibacterial drugs is a necessary approach to minimize the abundance of multidrug-resistant bacteria in farming and during the whole production chain. Especially in livestock farming, alternative and preventive strategies against infections are required as multidrug-resistant bacteria can be transmitted to humans via the food chain. This project aims to isolate new phages with broad bacterial host spectra for the use against Extended spectrum beta lactamase (ESBL) Escherichia coli infections in broilers, as this bacterial species causes the most frequent infections in chicken breeding.
Thus far, we isolated 43 bacteriophages from 24 environmental samples (sewage water 21, surface water 4, poultry dung 12, horse dung 1, and hospital wastewater 5) collected in varying places of Germany (Lower Saxony, Saarland and North-Rhine Westfalia). Host range analyses were performed by spot tests on 42 clinical isolates, 12 isolates from poultry meat, and 13 APEC (avian pathogenic E. coli) strains. To confirm phage activity the efficiency of plating method (EOP) was performed and revealed considerable differences to the host range determined by spot test.
Phages with the broadest host range and the highest EOP will be pre-characterized with regard to their biological features like one-step growth curves and electron microscopy. Furthermore, bioinformatic analyses of phage genomes will be performed in order to choose and combine the most suitable virulent phages into a phage cocktail for practical applications. To simulate in vivo conditions prior to field tests, the efficacy of phages will be tested in situ on poultry skin in combination with EOP.