Microbiological and Molecular Evaluation of the Extra intestinal Pathogenic E. coli Isolates from Poultry, Bovine, and Human for Determining its Zoonotic Potential

Abstract

According to One Health concept, the health of humans, animals, and environment is interconnected. This concept is centered on the ramifications, interventions, and measures taken at the interface where animals, humans, and ecosystems converge, with particular emphasis on the emerging and zoonotic infections, antimicrobial resistance transmission to humans via infected food consumption and/or through direct or indirect contact with the infected animals, and food safety. The hypothesis that human ExPEC may have a food animal reservoir has been a topic of investigation by multiple groups around the world. To validate the zoonotic risk posed by ExPEC in chicken and bovine, and to fill existing knowledge gaps regarding ExPEC zoonosis, Avian Pathogenic E. coli (APEC) from colibacillosis infected chickens, Mammary Pathogenic E. coli (MPEC) from infected bovines, and E. coli samples isolated from poultry and dairy environment. The present study has shown that sub-clinical mastitis is a widely prevalent disease of the dairy herds at both cow and herd-level and that there are several risk factors associated with the occurrence of mastitis in lactating animals. Farm owners'/attendants’ responses showed that they lack sufficient awareness and perception about bovine mastitis including subclinical form. E. coli isolates were evaluated for their antibiotic susceptibility patterns and ESBLs profiling and results suggested that 92% of the E. coli are multidrug resistant (MDR) with penicillin, tetracycline, macrolide, and fluoroquinolones being the least effective antibiotic classes. The high prevalence of blaCTX and blaTEM in E. coli was detected and is of high concern as the co-occurrence of different types of β-lactamases in E. coli isolates poses diagnostic and treatment problems. E. coli have heterogeneity in their pathogenic ability, and it is argued that the E. coli containing certain repertoire of genotypes and phenotypes are better suited for stronger virulence than others. It was found that strains showing higher motility and biofilm formation ability were more pathogenic. Results showed that most of the ExPEC belonged to the phylogenetic group B2 and D. This study provides detailed assessment of virulence associated phenotypes and genotypes, including in vivo virulence in chicken and mice models, of ExPEC isolates from various sources. It was also shown that animal and human ExPEC isolates have various overlapping genes. Multiple bovine and poultry source ExPEC isolates resembled clinical ExPEC isolates were able to cause UTI infection and lethal sepsis in mice models and the ExPEC isolates that resembled poultry-ExPEC isolates were also successful in causing colibacillosis in chicken models and showed high and intermediate pathogenicity index. While none of the isolates that were classified as non-ExPEC were able to cause ExPEC-associated illnesses in animal models. These findings suggest that E. coli isolates from animal feces and raw milk & meat that contain ExPEC associated genes and exhibit ExPEC-associated in vitro phenotypes may pose a health threat to humans and other animals via zoonosis.