Final answer:
Pyelonephritis, a kidney infection, is usually caused by Escherichia coli, a bacterium normally found in the large intestine, and is treated with antibiotics following a urinalysis.
Step-by-step explanation:
Pyelonephritis is usually caused by Escherichia coli, a normal flora organism in the large intestine. This serious kidney infection typically results when E. coli bacteria travel from an infection in another part of the urinary tract, such as the bladder, to the kidneys. It may lead to systemic complications if left untreated. In cases of pyelonephritis, broad-spectrum antibiotics are usually prescribed after conducting a urinalysis which may include tests for leukocyte esterase levels, nitrite levels, microscopic evaluation, and urine culture. Good hygiene practices can help prevent the transfer of E. coli from the large intestine to the urinary tract.