Kidney Infection: Causes, Symptoms & Transmission

Kidney infections, also called pyelonephritis, are usually caused by bacteria that enter the urinary tract through the urethra and multiply in the kidneys. These bacteria can come from the person's own body, such as from the skin or rectum, or they can be introduced from outside sources, such as during sexual intercourse or the use of contaminated medical instruments.

Direct transmission of a kidney infection from one person to another is rare. This could only occur if infected urine or contaminated objects were to come into direct contact with the urethra of another person. In most cases, kidney infections are acquired through indirect routes, such as through contact with contaminated water or surfaces, or through the spread of bacteria from other parts of the body.