Prev post1 of 3Next A kidney infection, also known as pyelonephritis, is usually caused by a bacterial infection that spreads up from the urinary tract to the bladder through the urethra and, finally, into the kidneys. It can affect one or both kidneys. Women, especially pregnant women, have a high risk of kidney infection compared to
3 Herbs That Relieve Kidney Infections. Kidney infections are a result of a bacterial infection that usually starts out as a urinary tract infection. The bacterium causing the infection can travel all the way to the kidneys, causing an infection there as well. Women are more prone to infections of this kind because of the proximity of the urethra, vagina, and anus.