This refers to a bacterial infection anywhere in the urinary tract, such as the bladder, kidneys, ureters, or the urethra. While most cases of bladder infection occur suddenly (acute), others may recur over the long-term (chronic).his refers to a bacterial infection anywhere in the urinary tract, such as the bladder, kidneys, ureters, or the urethra. While most cases of bladder infection occur suddenly (acute), others may recur over the long-term (chronic).