Urinary tract infections (UTIs) are the commonest human bacterial infections and are responsible for substantial morbidity and mortality, resulting in increased healthcare costs. Most UTIs are caused by specialized Escherichia coli (E. coli) strains referred to as uropathogenic E. coli (UPEC). UPEC possess a variety of virulence factors (VFs), which the organism uses to attach, invade, and injure the host. These VFs include adhesins, toxins, iron acquisition factors, lipopolysacharide capsules, and other invasins. Most studies on UTI pathogenesis have targeted VFs. The source of UPEC is the host’s fecal flora. According to the pathogenicity theory, UPEC strains with special VFs move from the host’s fecal flora to the urogenital tract and cause UTI. However, another theory states that the numerically abundant strain is responsible for UTI. Effective UTI management is hampered by the recent rise in antibiotic resistance, specifically, the recent emergence of multidrug-resistant E. coli sequence type 131. The distribution of VFs and other bacterial characteristics among different patient groups and UTI syndromes, is crucial understanding UTI pathogenesis, which would guide clinical decision making. For ST131 clonal group, further epidemiological studies are needed to clarify transmission pathways, risk factors for spread, and reservoirs, so that effective control measures can be devised
