Prevention Of Recurrent Urinary Infections Research Articles

Pharmacodynamics of D-mannose in the prevention of recurrent urinary infections

Recurring urinary tract infections (rUTIs) are frequently caused by Escherichia coli, which invades urothelial cells and forms quiescent bacterial reservoirs. D-mannose, an inert monosaccharide, represents a notable agent for rUTI prevention; however, there is no agreement on its dosage. To provide pharmacological basis for an effective dose, we evaluated its ability to inhibit adhesion of E. coli to urothelial cells. E. coli strains isolated from the urine of a woman with recurrent urinary tract infections were selected according to adhesion capacity. Anti-adhesive efficacy and invasion were tested using the TCC-5637 urothelial cell line. The IC50 for the anti-adhesive efficacy and anti-invasion activity of D-mannose were 0.51 mg/ml and 0.30 mg/ml, respectively, both with concentration-dependent inhibition. Lastly, the biofilm interference of D-mannose was evaluated to be 50 mg/ml. D-mannose inhibited the adhesion of E. coli to urothelial cells at high concentrations, whereas inhibition of invasion occurred at much lower concentrations.

Efficacy and safety profile of long-term nitrofurantoin in urinary infections: 18 years' experience.

Case records from 219 female patients between 1975 and 1992 who were given long-term prophylaxis (1 year) with nitrofurantoin for the prevention of recurrent urinary infections have been reviewed. Patients' age ranged from 9 to 89 years (median 31-35 years, mode 26-30 years); most (61%) were < 40 years old. The median number of symptomatic episodes in the 12 months immediately before prophylaxis was six (mode 4, mean 6.9). 14.4% of the patients were allergic to an antibiotic, and 23.6% had an imaging abnormality. Three regimens were used: group A (43 patients), 50 mg microcrystalline nitrofurantoin, bd; group B (110 patients), 100 mg macrocrystalline nitrofurantoin (Macrodantin), od; group C (66 patients), 50 mg Macrodantin, od. There were no obvious differences in efficacy between the patient groups (173 assessable patients). The mean incidence of symptomatic episodes decreased 5.4-fold during prophylaxis. Four-fifths of the 43 breakthrough infections (mostly due to Escherichia coli), were caused by nitrofurantoin-sensitive strains. An important finding was that patients with an imaging abnormality responded as well as those with no such abnormalities. In 16% of patients, prophylaxis was not helpful, objectively or subjectively, for no obvious reasons. In most patients where prophylaxis was successful, clinical improvement was maintained for at least 6 months after the end of prophylaxis. Nausea was more common in group A (P < 0.001), as were 'all adverse events'. Of those in group A 25.6% stopped prematurely as a result of an adverse event of any type, compared with 13% of those taking Macrodantin (P < 0.01). Older patients (> 65 years) did not report more adverse events than younger patients. No adverse event was life-threatening. Faecal flora analysis showed neither overgrowth by nitrofurantoin-resistant bacteria nor elimination of sensitive coliforms. Thus, macrocrystalline nitrofurantoin 50 mg at bedtime is appropriate for use in the long-term (12 months) prophylaxis of recurrent urinary infections, in view of its efficacy and favourable safety and tolerability profile. Patients can be managed by their family doctor.

Comparative Trial of Norfloxacin and Macrocrystalline Nitrofurantoin (Macrodantin) in the Prophylaxis of Recurrent Urinary Tract Infection in Women

Eighty-eight women with a history of recurrent urinary tract infection (at least four attacks in the preceding 12 months) were randomized to take either norfloxacin 200 mg at night (45 patients) or macrocrystalline nitrofurantoin 100 mg at night (43 patients) for 12 months. A decrease in the number of symptomatic attacks while taking this prophylaxis was observed in 94 per cent of the patients and this improvement was maintained during the 6 months following the end of prophylaxis in 69 per cent. The mean interval between symptomatic episodes while taking prophylaxis was 7.2-fold and 6.9-fold greater, respectively, than in the 12 months before starting prophylaxis. There were only nine breakthrough infections during 74 patient-years of prophylaxis, four in patients taking norfloxacin (two enterococci, one Staphylococcus epidermidis, one Escherichia coli), and five in those taking macrocrystalline nitrofurantoin (four E. coli, one Klebsiella pneumoniae). Adverse events caused four patients taking norfloxacin (8 per cent) and seven taking macrocrystalline nitrofurantoin (14 per cent) to stop prophylaxis. Norfloxacin had a marked suppressive effect on the coliform part of the faecal flora, with no emergence of resistance. Thus, norfloxacin appears to be an excellent alternative agent to macrocrystalline nitrofurantoin for the prevention of recurrent urinary infections.

Prevention of Recurrent Urinary Infections in Women: A Comparative Trial Between Nitrofurantoin and Methenamine Hippurate

We treated 99 female patients suffering from recurrent urinary infections with either 1gm. methenamine hippurate every 12 hours or 50mg. nitrofurantoin every 12 hours for intervals of up to 1 year. Monthly microbiological and clinical surveillance was done. Both treatments were effective in reducing the incidence of symptomatic attacks, with nitrofurantoin being more effective. The protective effect of prophylaxis continued after treatment had stopped, suggesting that a permanent beneficial action had been produced. Especially during the first month of treatment methenamine hippurate was tolerated better than nitrofurantoin: 28 per cent discontinued therapy with the latter owing to nausea.