Can regular intake of either cranberry juice or a drink containing Lactobacillus bacteria prevent urinary tract infection (UTI) recurrence in women after an initial episode?

BACKGROUND: UTIs are common in adult women, and many will have recurrences of UTI. The effectiveness of cranberry juice or Lactobacillus in preventing such recurrences is not known.

POPULATION STUDIED: The authors recruited women with culture-confirmed Escherichia coli UTI from university students and staff of a university hospital in Finland (n=149). Participants had an average age of 30 years and averaged 6 previous UTIs. Only 5 patients were older than 55 years. The study groups were similar; however, the cranberry juice group had a slightly higher previous use of antibiotics. The population studied would likely fit the practices of many family physicians. Eighty-five percent of the women had taken antimicrobials for a UTI in the year before enrollment. All were treated for their index episode of UTI with 5 days of standard drug therapy (communication with authors). Most (78%) used birth control during the study; none used a diaphragm or spermicides. Five women became pregnant during the 1-year follow-up.

STUDY DESIGN AND VALIDITY: Patients were randomized to 1 of 3 groups, with study personnel unaware of patients’ treatment assignments until after they were enrolled (concealed allocation; communication with authors). Fifty patients received daily oral concentrate (50 mL) of cranberry-lingonberry juice for 6 months. They were to dilute the concentrate with 200 mL of water. This product is no longer commercially available, even in Finland. In the second group, 49 patients took a Lactobacillus drink 5 days a week for 12 months. The 100-mL drink contained 4 × 1010 cfu of Lactobacillus. There were 50 untreated control patients. Treating physicians and patients were not blinded to the treatment assignment. Each recurrence was treated with nitrofurantoin for 5 days (communication with authors).

OUTCOMES MEASURED: The primary outcome measured was recurrence of UTI within 1 year. Patient symptoms were confirmed with culture to diagnose each recurrence.

RESULTS: Daily cranberry juice significantly decreased the incidence of UTI. Lactobacillus ingestion did not change the recurrence rate. Eight patients in the cranberry group had at least one recurrent UTI, compared with 19 in the Lactobacillus group and 18 in the control group (P=.023; number needed to treat [NNT]=5; 95% confidence interval [CI], 3-34). At 12 months, 12 patients in the cranberry group had a recurrent UTI, compared with 21 in the Lactobacillus group and 19 in the control group (P=.048; NNT=7). Most (80%) of the recurrences were due to E coli.

BACKGROUND: UTIs are common in adult women, and many will have recurrences of UTI. The effectiveness of cranberry juice or Lactobacillus in preventing such recurrences is not known.

POPULATION STUDIED: The authors recruited women with culture-confirmed Escherichia coli UTI from university students and staff of a university hospital in Finland (n=149). Participants had an average age of 30 years and averaged 6 previous UTIs. Only 5 patients were older than 55 years. The study groups were similar; however, the cranberry juice group had a slightly higher previous use of antibiotics. The population studied would likely fit the practices of many family physicians. Eighty-five percent of the women had taken antimicrobials for a UTI in the year before enrollment. All were treated for their index episode of UTI with 5 days of standard drug therapy (communication with authors). Most (78%) used birth control during the study; none used a diaphragm or spermicides. Five women became pregnant during the 1-year follow-up.

STUDY DESIGN AND VALIDITY: Patients were randomized to 1 of 3 groups, with study personnel unaware of patients’ treatment assignments until after they were enrolled (concealed allocation; communication with authors). Fifty patients received daily oral concentrate (50 mL) of cranberry-lingonberry juice for 6 months. They were to dilute the concentrate with 200 mL of water. This product is no longer commercially available, even in Finland. In the second group, 49 patients took a Lactobacillus drink 5 days a week for 12 months. The 100-mL drink contained 4 × 1010 cfu of Lactobacillus. There were 50 untreated control patients. Treating physicians and patients were not blinded to the treatment assignment. Each recurrence was treated with nitrofurantoin for 5 days (communication with authors).

OUTCOMES MEASURED: The primary outcome measured was recurrence of UTI within 1 year. Patient symptoms were confirmed with culture to diagnose each recurrence.

RESULTS: Daily cranberry juice significantly decreased the incidence of UTI. Lactobacillus ingestion did not change the recurrence rate. Eight patients in the cranberry group had at least one recurrent UTI, compared with 19 in the Lactobacillus group and 18 in the control group (P=.023; number needed to treat [NNT]=5; 95% confidence interval [CI], 3-34). At 12 months, 12 patients in the cranberry group had a recurrent UTI, compared with 21 in the Lactobacillus group and 19 in the control group (P=.048; NNT=7). Most (80%) of the recurrences were due to E coli.

BACKGROUND: UTIs are common in adult women, and many will have recurrences of UTI. The effectiveness of cranberry juice or Lactobacillus in preventing such recurrences is not known.

POPULATION STUDIED: The authors recruited women with culture-confirmed Escherichia coli UTI from university students and staff of a university hospital in Finland (n=149). Participants had an average age of 30 years and averaged 6 previous UTIs. Only 5 patients were older than 55 years. The study groups were similar; however, the cranberry juice group had a slightly higher previous use of antibiotics. The population studied would likely fit the practices of many family physicians. Eighty-five percent of the women had taken antimicrobials for a UTI in the year before enrollment. All were treated for their index episode of UTI with 5 days of standard drug therapy (communication with authors). Most (78%) used birth control during the study; none used a diaphragm or spermicides. Five women became pregnant during the 1-year follow-up.

STUDY DESIGN AND VALIDITY: Patients were randomized to 1 of 3 groups, with study personnel unaware of patients’ treatment assignments until after they were enrolled (concealed allocation; communication with authors). Fifty patients received daily oral concentrate (50 mL) of cranberry-lingonberry juice for 6 months. They were to dilute the concentrate with 200 mL of water. This product is no longer commercially available, even in Finland. In the second group, 49 patients took a Lactobacillus drink 5 days a week for 12 months. The 100-mL drink contained 4 × 1010 cfu of Lactobacillus. There were 50 untreated control patients. Treating physicians and patients were not blinded to the treatment assignment. Each recurrence was treated with nitrofurantoin for 5 days (communication with authors).

OUTCOMES MEASURED: The primary outcome measured was recurrence of UTI within 1 year. Patient symptoms were confirmed with culture to diagnose each recurrence.

RESULTS: Daily cranberry juice significantly decreased the incidence of UTI. Lactobacillus ingestion did not change the recurrence rate. Eight patients in the cranberry group had at least one recurrent UTI, compared with 19 in the Lactobacillus group and 18 in the control group (P=.023; number needed to treat [NNT]=5; 95% confidence interval [CI], 3-34). At 12 months, 12 patients in the cranberry group had a recurrent UTI, compared with 21 in the Lactobacillus group and 19 in the control group (P=.048; NNT=7). Most (80%) of the recurrences were due to E coli.