Pathogenic Escherichia coli: Virulence Factors and Their Antimicrobial Resistance

Escherichia coli (E. coli) falls under the family Enterobacteriaceae with the genus Escherichia. They are facultative anaerobic bacteria mostly at 37 °C and due to the presence of peritrichous flagella; they can be motile or nonmotile. They are enteric bacteria belonging to naturally beneficial flora of humans as well as gastrointestinal tract of warm-blooded animals. The pathotypes of pathogenic enteric E. coli strains have been classified into six groups which include Enterotoxigenic E. coli (ETEC), Enteropathogenic E. coli (EPEC), Enterohemorrhagic E. coli (EHEC), Enteroaggregative E. coli (EAEC), Enteroinvasive E. coli (EIEC), and diffusely adhering E. coli (DAEC). Another pathotype, adherent-invasive E. coli (AIEC) which is the seventh group is observed along with Crohn’s disease. E. coli infection in humans is usually observed while consuming food products that are contaminated that may belong to either animal origin foods, fresh vegetables, water meant for drinking contaminated by animal or human wastes. Some of the infections include UTI, gastrointestinal infections, neonatal meningitis, colorectal cancer, etc. Besides, multidrug resistance in E. coli is being increasingly observed across the world, which leads to a fearing issue both in humans and also in veterinary medicine field. The highly resistant drugs include tetracycline, quinolones, and carbapenemase. The ability of E. coli to form biofilm also makes the organisms resistant to different antimicrobial drugs.