Zoonotic Watch: Molecular Screening for Virulence of the Avian Pathogenic E. coli and It’s In vivo Confirmation for Zoonotic Potential

Abstract

According to WHO, around 60% of known and 75% of emerging human infections are zoonotic. Poultry is the second largest industry of Pakistan, contributing 23% of all meat production at the national level and generating employment for 1.5 million people. The Avian pathogenic Escherichia coli (APEC) is one of the most common bacteria infecting poultry, causing up to 20% mortality in chickens, but neglected for investigating its zoonotic potential. The study aimed to design a user friendly app to enable real-time reporting of animal infections and investigate their zoonotic potential, focusing initially on APEC. The strains of E. coli (PSU-5070 and PSU-5071) isolated from chicken liver were confirmed to be APEC via in silico and in vitro analysis. UPEC and SEPEC-associated zoonotic markers were investigated in APEC isolates by NCBI Pathogen Detection and GalaxyTrakr software and further confirmed by urine growth and complement resistance assays, respectively. Enterobase software was used for serotyping, phylotyping, and MLST. The sepsis potential of APEC isolates in mammals was explored by intraperitoneal injection of APEC in mice models, keeping UPEC as positive and commensal E. coli as negative controls and observing their illness severity score for 5 days. The results confirmed that PSU-5070 belonged to phylogroup C with an O2:H40 serotype while PSU-5071 was from phylogroup G with an O33:H4 serotype. Both strains exhibit growth in human urine, complement resistance in blood, and were positive for UPEC and SEPEC-associated VAGs suggesting the presence of zoonotic markers. Sepsis in the mice model was confirmed as the survival rate was 0% in the case of PSU-5070 and 60% with PSU-5071 injection, within 24 hours. The user-friendly zoonotica app was also designed to allow widespread participation and relatively faster data collection on zoonotic outbreaks. VAGs analysis in APEC revealed the presence of potential genes that could be used as zoonotic markers. In silico, in vitro, and in vivo analysis confirms the sepsis potential of APEC isolates in mammals. This emphasizes the importance of further investigating APEC’s potential to infect humans.