Urinary tract infections (UTIs) can be divided into upper tract infections, which involve the kidneys, and lower tract infections, which involve the bladder, urethra, or prostate. However, in practice, and particularly in children, differentiating between the sites may be difficult or impossible. Moreover, infection often moves from one area to the other.

Most UTIs are caused by enteric bacteria. The remainder are due to sexually transmitted pathogens (see Sexually Transmitted Diseases (STDs): Overview of Sexually Transmitted Diseases), mycobacteria (see Mycobacteria: Introduction), fungi (see Fungi: Overview of Fungal Infections and see Urinary Tract Infections (UTI): Fungal Urinary Tract Infections), viruses, and parasites. The predominant parasitic causes of UTIs are filariasis, trichomoniasis, leishmaniasis, malaria, and schistosomiasis. These parasitic diseases are discussed in other chapters of The Manual. Of the parasitic diseases, only trichomoniasis is common in the US. Adenoviruses are implicated in hemorrhagic cystitis.

Last full review/revision September 2007 by Stewart Shankel, MD

Content last modified February 2012