Generally, in accordance with anatomical characteristics, urinary tract infections (UTIs) and in particular recurrent UTIs occur in women; in contrast, UTIs normally occur in men with different predisposing factors. There are several types of UTIs, including asymptomatic and symptomatic, complicated and uncomplicated, acute and chronic with a diversity of microbial pathogens. In pathogens, virulence factors and genes determine the type and severity of the UTIs. Obviously, UTIs are a huge problem in global public healthcare systems with a wide range of predisposing factors, including gender, microbial agent, the host's immune deficiencies, genetic diseases, catheterization, etc. The recent items determine the microbiology of UTIs. Accurate diagnosis and definitive treatment are the key to UTI reduction.