Recurrent urinary tract infection (UTI) refers to ≥2 infections in six months or ≥3 infections in one year. Most recurrences are thought to represent reinfection rather than relapse, although occasionally a persistent focus can produce relapsing infection. It is useful to try to distinguish clinically between relapse and reinfection, because relapsing infection warrants more extensive urologic evaluation, longer therapy, and, in some cases, surgery.
However, this distinction is rarely necessary in young healthy women with recurrent UTIs. There is no evidence that recurrent UTI leads to health problems, such as hypertension or renal disease, in the absence of anatomic or functional abnormalities of the urinary tract.
The epidemiology, pathogenesis, and prevention of recurrent acute uncomplicated cystitis and pyelonephritis in young, healthy non-pregnant women will be reviewed here. These infections are generally caused by the same organisms and share clinical features, diagnostic testing, and treatment regimens with sporadic uncomplicated infection. (See "Acute uncomplicated cystitis and pyelonephritis in women".)
The management of asymptomatic bacteriuria, including in pregnancy, is discussed separately. (See "Approach to the adult with asymptomatic bacteriuria".)
Recurrent uncomplicated UTIs are common among young, healthy women even though they generally have anatomically and physiologically normal urinary tracts. In a study of college women with their first UTI, 27 percent experienced at least one culture-confirmed recurrence within the six months following the initial infection and 2.7 percent had a second recurrence during this same time period . When the first infection is caused by Escherichia coli, women appear to be more likely to develop a second UTI within six months than those with a first UTI due to another organism . In a Finnish study of women ages 17 to 82 who had E. coli cystitis, 44 percent had a recurrence within one year . Recurrent pyelonephritis in healthy women is very uncommon, but there are no prevalence data available.