Uropathogenic Escherichia coli virulence and innate immune responses during urinary tract infection

Urinary tract infections (UTI) are among the most common infectious diseases of humans and are the most common nosocomial infections in the developed world. It is estimated that 40–50% of women and 5% of men will develop a UTI in their lifetime, and UTI accounts for more than 1 million hospitalizations and $1.6 billion in medical expenses each year in the USA. Uropathogenic Escherichia coli (UPEC) is the primary cause of UTI. This review presents an overview of recent discoveries related to the primary virulence factors of UPEC and major innate immune responses to infection of the lower urinary tract. New and emerging themes in UPEC research are discussed in the context of the interface between host and pathogen.

► UPEC express multiple virulence factors that promote UTI.
► The genetic diversity of UPEC supports intracellular and extracellular lifestyles.
► UPEC manipulate innate immune responses to enhance their survival.
► Excessive inflammation induced by UPEC predisposes to chronic and recurrent UTI.
► Controlling immunopathology may represent a novel therapeutic approach for UTI.