What is the primary cause of kidney infections?

The primary cause of kidney infections, also known as pyelonephritis, is the entry of bacteria through the urethra. This route of infection often involves bacteria migrating from the lower urinary tract, such as the bladder, where they can ascend to the kidneys. The most common pathogens responsible for such infections are Escherichia coli (E. coli), which is normally found in the intestinal tract but can cause urinary tract infections when they enter the urinary system.

When bacteria enter the urinary tract, they can adhere to the bladder wall and proliferate, potentially moving upwards to infect the kidneys. This ascending infection can trigger a range of symptoms and potentially lead to serious complications if not treated promptly.

Other factors, such as inadequate hygiene practices or a diet high in sugars, may contribute to an increased risk of urinary tract infections but are not the primary cause. Excessive fluid consumption typically helps flush the urinary tract and can prevent infections rather than cause them. Thus, the bacterial entry through the urethra is a key factor in the development of kidney infections.