Comparative trial of trimethoprim and co-trimoxazole in recurrent urinary infections

[Current state of resistance of E. coli to trimethoprim in uncomplicated urinary tract infections in France]

OBJECTIVE

The objective of this study was to assess the level of resistance of trimethoprim alone (TMP) with respect to E. coli strains isolated from the urines of women with simple acute cystitis in community.

PATIENTS AND METHODS

Prospective study realized for 9 months in 2017-18. A total of 351 urine samples were analyzed. Culture has been made according to the usual techniques and antibiogram was carried out according to the recommendations of the CA-SFM.

RESULTS

The rate of resistance to TMP was 16.5% (58/351). Only 11 strains of E. coli (3%) producing ESBL were found, 5 of which were sensitive to TMP.

CONCLUSION

The resistance rate of E. coli to TMP remains below 20%, the threshold for choosing a probabilistic treatment of a non-serious infection. Considering the good tolerance of TMP and its weak effect on the microbiota during a short treatment, one can propose TMP alone in the probabilistic treatment of simple acute cystitis.

Limitations of and indications for the use of co-trimoxazole

Co-trimoxazole is still widely used for indications where trimethoprim alone is equally effective. Microbiological and pharmacokinetic considerations reveal that trimethoprim alone provides adequate anti-microbial activity for treatment of conditions for which co-trimoxazole is often given. Synergy may be shown in vitro, but in clinical practice is an unusual occurrence. There is no evidence from clinical studies that the sulphonamide moiety fo co-trimoxazole prevents the development of resistance to trimethoprim. The adverse event profile of co-trimoxazole is a summation of that of sulphonamide and of trimethoprim. Thus, using trimethoprim alone should reduce both the incidence and potential severity of adverse events seen when co-trimoxazole is used. Clinical trials have shown trimethoprim to be as effective as co-trimoxazole in many of the common bacterial infections of the urinary and respiratory tracts. However, there are a few specific varieties of infection for which co-trimoxazole can be shown to be superior to trimethoprim: these include toxoplasmosis, brucellosis, nocardiosis, chancroid and pneumonia caused by Pneumocystis carinii. For many common infections, scientific, rational, economic and clinical reasons dictate that trimethoprim is preferable to co-trimoxazole.

Comparative trial of cefuroxime axetil in recurrent urinary tract infections illustrating importance of 6-week follow-up

Women with recurrent urinary tract infections treated with cefuroxime axetil (500 or 250 mg twice daily) for 7 days had a higher relapse rate when tested 6 weeks after the start of treatment than those given amoxycillin (250 mg three times daily). The poor performance of cefuroxime axetil is explained by variable bioavailability.

Antibiotic sensitivities of urinary pathogens isolated from patients in Liverpool, 1984-5

Urinary pathogens isolated from patients in general practice, an antenatal clinic and several hospitals in Liverpool during 1984-5 have been tested for antibiotic sensitivities. The proportion of sensitive organisms varied from antimicrobial to antimicrobial and from institution to institution. Isolates from all institutions showed high rates of sensitivity to cephradine, nalidixic acid and nitrofurantoin, and somewhat lower rates to trimethoprim. Significantly lower sensitivities were found to ampicillin and sulphamethoxazole indicating that neither ampicillin nor a sulphonamide is suitable for initial choice on a 'best guess' basis in the situation studied. In general, the organisms derived from the antenatal patients showed the highest rates of sensitivity and those isolated from patients in geriatric hospitals the lowest.

Amoxicillin plus clavulanic acid in the treatment of recurrent urinary tract infections

Forty-four patients (43 female, 1 male), all with a history of recurrent urinary tract infections, were treated with 250 mg of amoxicillin plus 125 mg of clavulanic acid (one tablet of Augmentin) every 8 h for 7 days. The microbiological cure rates were 84% 1 week after the end of treatment and 67% 1 month later. Side effects, which were reported by 20% of the patients, were mild and in no case caused interruption of treatment. In view of the increasing trend in resistance to agents commonly used for the treatment of urinary tract infections in outpatients, the combination of amoxicillin and clavulanic acid may now be considered a first-line drug in patients with recurrent urinary tract infections.

Steady state pharmacokinetics of trimethoprim 300 mg once daily in healthy volunteers assessed by two independent methods

The steady state pharmacokinetics of trimethoprim was determined after 300 mg orally once daily to 6 healthy volunteers for 9 days. The microbiological assay of plasma level was unreliable at trimethoprim concentrations greater than 4 micrograms/ml, so results from an HPLC-assay are given. Steady state was present after 3 days. The plasma concentration peaked 1 to 4 h (mean 2.0 h) after the dose at a mean of 6.0 micrograms/ml (range 3.1-9.5 micrograms/ml); the minimum value was 1.5 micrograms/ml (range 0.6-2.9 micrograms/ml). The mean AUCss was 77 micrograms/ml X h and the mean plasma clearances was 67 and 74 ml/min on Days 8 and 9. Renal clearance was about 60% of the plasma clearance. The average plasma half life was 10.6 h (range 8.7-15.3 h). Thus, there was considerable interindividual variation in all pharmacokinetic parameters. 72 h after the last dose trimethoprim was detectable in plasma in only 1 of the 6 subjects. The minimum urinary concentration of trimethoprim during treatment was always well above (range 22 to 220 micrograms/ml) the MIC values for most urinary tract pathogens. Therefore, a daily dose of 300 mg trimethoprim results in a therapeutic concentration in urine at steady state that lasts throughout the dosing interval and in most subjects probably lasts also for a further 24 h. Trimethoprim administration raised mean serum creatinine from 67 to 97 mumol/l, probably due to competitive inhibition of the tubular secretion of creatinine.