Three-day and ten-day chemotherapy for urinary tract infections in general practice

Integrating Antimicrobial Therapy with Host Immunity to Fight Drug-Resistant Infections: Classical vs. Adaptive Treatment

Antimicrobial resistance of infectious agents is a growing problem worldwide. To prevent the continuing selection and spread of drug resistance, rational design of antibiotic treatment is needed, and the question of aggressive vs. moderate therapies is currently heatedly debated. Host immunity is an important, but often-overlooked factor in the clearance of drug-resistant infections. In this work, we compare aggressive and moderate antibiotic treatment, accounting for host immunity effects. We use mathematical modelling of within-host infection dynamics to study the interplay between pathogen-dependent host immune responses and antibiotic treatment. We compare classical (fixed dose and duration) and adaptive (coupled to pathogen load) treatment regimes, exploring systematically infection outcomes such as time to clearance, immunopathology, host immunization, and selection of resistant bacteria. Our analysis and simulations uncover effective treatment strategies that promote synergy between the host immune system and the antimicrobial drug in clearing infection. Both in classical and adaptive treatment, we quantify how treatment timing and the strength of the immune response determine the success of moderate therapies. We explain key parameters and dimensions, where an adaptive regime differs from classical treatment, bringing new insight into the ongoing debate of resistance management. Emphasizing the sensitivity of treatment outcomes to the balance between external antibiotic intervention and endogenous natural defenses, our study calls for more empirical attention to host immunity processes.

"One-size-fits-all"? Optimizing treatment duration for bacterial infections

Historically, antibiotic treatment guidelines have aimed to maximize treatment efficacy and minimize toxicity, but have not considered the evolution of antibiotic resistance. Optimizing the duration and dosing of treatment to minimize the duration of symptomatic infection and selection pressure for resistance simultaneously has the potential to extend the useful therapeutic life of these valuable life-saving drugs without compromising the interests of individual patients.Here, using mathematical models, we explore the theoretical basis for shorter durations of treatment courses, including a range of ecological dynamics of bacteria that cause infections or colonize hosts as commensals. We find that immunity is an important mediating factor in determining the need for long duration of treatment. When immunity to infection is expected, shorter durations that reduce the selection for resistance without interfering with successful clinical outcome are likely to be supported. Adjusting drug treatment strategies to account for the impact of the differences in the ecological niche occupied by commensal flora relative to invasive bacteria could be effective in delaying the spread of bacterial resistance.

Three-day treatment of acute lower urinary tract infections in women. A double-blind study with amoxycillin and co-trimazine

The aim of this study was to determine if a three-day treatment of lower urinary tract infection (UTI) is effective. 215 women with symptoms of lower UTI, seen in general practice, were randomly allocated to a double-blind study and given either amoxycillin 1000 mg twice a day for three days or trimethoprim 90 mg/sulphadiazine 410 mg (co-trimazine) 2 tablets initially, then one tablet twice daily for three days. 157 women (73%) had significant bacteriuria. Therapeutic efficacy was evaluated in 146 patients. One week after treatment had started, 88% of the women in the amoxycillin group and 100% in the co-trimazine group were cured (p less than 0.01). After a follow-up period of four weeks, the cumulative relapse frequencies were 19% and 9% respectively. Adverse reactions were mild in most cases. Two patients, both on co-trimazine, had to discontinue treatment because of nausea and vomiting. Vulvovaginal irritation was more often reported by women treated with amoxycillin (n = 8) than by those treated with co-trimazine (n = 1) (p less than 0.05). It is concluded that a three-day course of amoxycillin or co-trimazine in lower UTI is safe, causes few adverse reactions, is simple to administer and comfortable for the patient. Co-trimazine seems to be more effective than amoxycillin.

One or three weeks' treatment of acute pyelonephritis? A double-blind comparison, using a fixed combination of pivampicillin plus pivmecillinam

The clinical and bacteriological effects of 1 and 3 weeks' pivampicillin plus pivmecillinam treatment were compared in a double-blind, randomized study of patients with acute pyelonephritis. Three weeks after the end of active treatment, clinical success was seen in 29 (91%) of the 32 patients on 1-week treatment, compared with 28 (97%) of the 29 patients treated for 3 weeks. Bacteriological success was seen in only nine (28%) patients in the 1-week group vs. 20 (69%) in the 3-week group (p = 0.004). This difference was mainly due to a large number of relapses of lower urinary tract infection in the 1-week group. Even in uncomplicated cases, the bacteriological result of the 1-week treatment was unsatisfactory. Side-effects were more common in the 3-week treatment group. In conclusion, 1-week treatment of patients with acute pyelonephritis is too short. Three weeks' treatment is effective in uncomplicated cases, but even longer treatment or low-dose prophylaxis is indicated in certain patients with predisposing factors.

Antibiotic duration for treating uncomplicated, symptomatic lower urinary tract infections in elderly women

BACKGROUND

Urinary tract infections (UTI) are common in elderly patients. Authors of non systematic literature reviews often recommend longer treatment durations (7 to 14 days) for older women, but the evidence for such recommendations is unclear.

OBJECTIVES

To determine the optimal duration of antibiotic treatment for uncomplicated symptomatic lower UTI in elderly women.

SEARCH STRATEGY

We contacted known investigators and pharmaceutical companies, screened reference lists of identified articles, reviews and books, and searched MEDLINE, EMBASE, CINAHL, Healthstar, Popline, Gerolit, Bioethics Line, The Cochrane Library, Dissertation Abstracts International and Index to Scientific & Technical Proceedings without language restriction. Date of most recent search: 7 May 2008.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing different treatment durations of oral antibiotics for uncomplicated symptomatic lower UTIs in elderly women were included. Whenever possible we obtained outcome data for older women included in studies with a broader age range. We excluded patients with fever, flank pain or complicating factors; studies with treatment durations longer than 14 days and prevention studies.

DATA COLLECTION AND ANALYSIS

The two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random effects model and results expressed as risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Fifteen studies (1644 elderly women) were included. Three studies compared single dose with short-course treatment (3 to 6 days), six compared single dose with long-course treatment (7 to 14 days) and six compared short- with long-course treatment. Methodological quality of all studies was low except for a more recent geriatric study. There was a significant difference for persistent UTI between single dose and short-course treatment (RR 2.01, 95% CI 1.05 to 3.84) and single versus long-course treatment (RR 1.93, 1.01 to 3.70 95% CI), in the short-term (< 2 weeks post-treatment) but not at long-term follow-up or on clinical outcomes. Patients preferred single dose treatment (RR 0.73, 95% CI 0.60 to 0.88) to long-course treatments, but this was based on one study comparing different antibiotics. Short versus longer treatments showed no significant difference in efficacy. Rate of adverse drug reactions increased significantly with longer treatment durations in only one study.

AUTHORS' CONCLUSIONS

Short-course treatment (3 to 6 days) could be sufficient for treating uncomplicated UTIs in elderly women, although more studies on specific commonly prescribed antibiotics are needed.

Three-day vs longer duration of antibiotic treatment for cystitis in women: systematic review and meta-analysis

PURPOSE

We performed a meta-analysis to ascertain the efficacy and safety of the currently practiced 3-day antibiotic therapy for cystitis versus prolonged therapy (5 days or longer) to relieve symptoms and to achieve bacteriological cure.

METHODS

The Cochrane Library, the Cochrane Renal Group's Register of trials, EMBASE and MEDLINE were searched to identify all randomized controlled trials comparing 3-day oral antibiotic therapy with prolonged therapy (5 days and longer) for uncomplicated cystitis in adult non-pregnant women. Two reviewers independently applied selection criteria, performed quality assessment, and extracted data. Relative risks (RR) with their 95% confidence intervals (CI) were estimated; a fixed effect model was used. An intention-to-treat analysis was performed whenever possible.

RESULTS

Thirty-two trials and 9605 patients met inclusion criteria. For symptomatic failure rates no difference between 3-day and prolonged antibiotic regimens was found at short term (RR 1.16, 95% CI: 0.96-1.41) and long-term follow-up (RR 1.17, 95% CI: 0.99-1.38). Three-day treatment was less effective than prolonged therapy in preventing bacteriological failure, relative risk 1.37 (95% CI: 1.07-1.74) for short-term follow-up, and 1.47 (95% CI: 1.22-1.77) for long-term follow-up. Adverse effects were more common in the prolonged therapy group (RR 0.83, 95% CI: 0.79-0.91). The results were consistent for subgroup and sensitivity analyses.

CONCLUSION

Antibiotic therapy for 3 days is similar to prolonged therapy in achieving symptomatic cure for cystitis, while the prolonged treatment is more effective in obtaining bacteriological cure.

Duration of antibacterial treatment for uncomplicated urinary tract infection in women

BACKGROUND

Uncomplicated urinary tract infection (UTI) is a common disease, occurring frequently in young sexually active women. In the past, seven day antibiotic therapy was recommended while the current practice is to treat uncomplicated UTI for three days.

OBJECTIVES

TO compare the efficacy and safety of three-day antibiotic therapy to multi-day therapy (five days or longer) on relief of symptoms and bacteriuria at short-term and long-term follow-up.

SEARCH STRATEGY

The Cochrane Library (Issue 1, 2004), the Cochrane Renal Group's Register of trials (July 2003), EMBASE (January 1980 to August 2003), and MEDLINE (January 1966 to August 2003) were searched. We scanned references of all included studies and contacted the first or corresponding author of included trials and the pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials comparing three-days oral antibiotic therapy with multi-day therapy (five days and longer) for uncomplicated cystitis in 18 to 65 years old non-pregnant women without signs of upper UTI.

DATA COLLECTION AND ANALYSIS

Data concerning bacteriological and symptomatic failure rates, occurrence of pyelonephritis and adverse effects were extracted independently by two reviewers. Relative risk (RR) and their 95% confidence intervals (CI) were estimated. Outcomes were also extracted by intention-to-treat analysis whenever possible.

MAIN RESULTS

Thirty-two trials (9605 patients) were included. For symptomatic failure rates, no difference between three-day and 5-10 day antibiotic regimen was seen short-term (RR 1.06, 95% CI 0.88 to 1.28) and long-term follow-up (RR 1.09, 95% CI 0.94 to 1.27). Comparison of the bacteriological failure rates showed that three-day therapy was less effective than 5-10 day therapy for the short-term follow-up, however this difference was observed only in the subgroup of trials that used the same antibiotic in the two treatment arms (RR 1.37, 95% CI 1.07 to 1.74, P = 0.01). This difference was more significant at long-term follow-up (RR 1.43, 95% CI 1.19 to 1.73, P = 0.0002). Adverse effects were significantly more common in the 5-10 day treatment group (RR 0.83, 95% CI 0.74 to 0.93, P = 0.0010). Results were consistent for subgroup and sensitivity analyses.

AUTHORS' CONCLUSIONS

Three days of antibiotic therapy is similar to 5-10 days in achieving symptomatic cure during uncomplicated UTI treatment, while the longer treatment is more effective in obtaining bacteriological cure. In spite of the higher rate of adverse effects, treatment for 5-10 days could be considered for treatment of women in whom eradication of bacteriuria is important.

All dysuria is local. A cost-effectiveness model for designing site-specific management algorithms

OBJECTIVE

To determine the cost-effectiveness of management strategies for dysuria in different office settings.

DESIGN

Decision and cost-effectiveness analyses, assuming the payer's perspective. Data on disease prevalence, test characteristics, treatment efficacy, and adverse effects were drawn from the English language literature using medline searches and bibliographies.

SETTING

Hypothetical primary care practice.

PATIENTS

Otherwise healthy, nonpregnant women with symptoms of dysuria, urgency, and frequency.

INTERVENTIONS

All reasonable combinations of urinalysis, urine culture, pelvic examination, chlamydia and gonorrhea cultures, and empiric treatment with trimethoprim-sulfamethoxazole.

RESULTS

The cost-effectiveness of strategies varied substantially among different patient settings. In all settings, empiric trimethoprim-sulfamethoxazole for all patients was least expensive and least effective. Most testing increased both cost and effectiveness. Compared to empiric antibiotics, performing pelvic examination and urine culture for women with normal urinalyses had a marginal cost-effectiveness ratio of $4 to $32 per symptom-day avoided (SDA). Adding urine culture for patients with pyuria had a marginal cost of $34 to $107 per SDA, which fell to $40/SDA when the prevalence of resistance to trimethoprim-sulfamethoxazole exceeded 40%. Pelvic examination and urine culture for all patients regardless of urinalysis results achieved the greatest benefit but at the highest cost (>$300 per SDA).

CONCLUSIONS

In otherwise healthy women with symptoms of dysuria and no vaginal complaints, performing pelvic exam and urine culture based on urinalysis offers a reasonable alternative to empiric therapy. Other testing may be warranted, depending on antibiotic resistance and the value of avoiding a day of dysuria.

Correlation between pharmacokinetic/pharmacodynamic parameters and efficacy for antibiotics in the treatment of urinary tract infection

Antibiotic treatment of urinary tract infection (UTI) depends on the antibiotic being able to inhibit the growth or to kill the bacteria present in the urinary tract. The pharmacokinetics of antibiotics in the urinary tract including the kidneys, the bladder and the prostate are briefly reviewed. The conclusion is that high urinary antibiotic concentrations can eradicate bacteria in the urine, but in the kidney tissue levels must surpass the MIC of the infecting pathogen to achieve effect. Pharmacodynamic studies in UTI are relatively scarce, but recent studies have shown, that as for other types of infections, beta-lactam antibiotic treatment of UTI depends on the T(>MIC), i.e. the time the antibiotic concentration remains above the MIC. This counts for activity against bacteria in the kidneys as well as in the urine. Bacterial counts in the bladder are curiously resistant to the activity of most antibiotics. For drugs with concentration dependent time-kill activity such as the fluoroquinolones and the aminoglycosides, the effect in UTIs is dependent on the peak/MIC ratio or AUC/MIC ratio. The aminoglycosides are difficult to evaluate in this context, since they are bound in high concentrations to the renal cortex. For clinical studies the author reviews the literature for aminopenicillins (ampicillin and amoxycillin) as representatives of beta-lactam antibiotics. Data from 16 studies of uncomplicated UTI encompassing 20 treatment groups showed a significant correlation between the cumulative T(>MIC) and bacteriological cure, such that a cumulative T(>MIC) of 30 h was necessary for a maximal cure rate of 80-90%. Incorporating these data including the T(>MIC) for the aminopenicillins, the optimal dose with minimal consumption of drug can be calculated, i.e. for amoxycillin 500 mg TID for 4 days. Further research is needed to calculate optimal dosages for other types of antibiotics, especially in order to prevent development of resistance.

Antibiotic duration for treating uncomplicated, symptomatic lower urinary tract infections in elderly women

BACKGROUND

Urinary tract infections are common in elderly patients. Authors of non systematic literature reviews often recommend longer treatment durations (7-14 days) for older patients than for younger women, but the scientific evidence for such recommendations is not clear.

OBJECTIVES

To determine the optimal duration of antibiotic treatment for uncomplicated symptomatic lower urinary tract infections in elderly women.

SEARCH STRATEGY

We contacted known investigators and pharmaceutical companies marketing antibiotics used to treat urinary tract infections, screened the reference list of identified articles, reviews and books, and searched the following data bases: MEDLINE, EMBASE, CINAHL, Healthstar, Popline, Gerolit, Bioethics Line, The Cochrane Library, Dissertation Abstracts International, Index to Scientific & Technical Proceedings.

SELECTION CRITERIA

All randomized controlled trials in which different treatment durations of oral antibiotics for uncomplicated symptomatic lower urinary tract infections in elderly women were compared. We excluded patients with fever or flank pain and those with complicating factors. Trials with treatment durations longer than 14 days or designed for prevention of urinary tract infection were also excluded. No language restriction was applied.

DATA COLLECTION AND ANALYSIS

The quality of all selected trials was assessed and data extracted by the reviewers. Main outcome measures were persistence of urinary symptoms (short-term and long-term efficacy), effect on mental and functional status and adverse drug reactions. To compare the different treatment durations, we defined the following categories of duration: single dose, short course (3-6 days) and long course (7-14 days). Relative risk (RR) and 95% confidence intervals (CI) were calculated for each trial and outcome and were then combined using a random effects model.

MAIN RESULTS

Thirteen trials were included in this review. Six trials compared single dose with short-term treatment (3-6 days), three studies single dose with long-term treatment (7-14 days) and four trials short-term with long term treatment. Eight trials also included younger patients, but provided a subgroup analysis for elderly women. The methodological quality of all trials was low. All trials reported results of bacteriological cure rate; less often clinical outcomes (e.g. improvement or cure of symptoms) were analyzed. Only five trials compared the same antibiotic given for a different length of time. We performed a separate analysis for these trials. The rate of persistent bacteriuria rate at short-term (two weeks post-treatment) was better in the longer treatment group (3-14 days) than in the single dose group (RR 1.84, 95% CI 1.18 to 2.86). However, the rate of persistent bacteria at long term and the clinical cure rate showed no statistically significant difference between the two groups. Patients showed a preference for single dose treatment (RR 0.73, 95% CI 0.66 to 0.88), however this was based on only one trial comparing the same antibiotic. The comparison of short (3-6 days) and longer treatments (7-14 days) did not show any significant difference, but the number of included studies and sample size were low.

REVIEWER'S CONCLUSIONS

This review suggests that single dose antibiotic treatment is less effective but may be better accepted by the patients than longer treatment durations (3-14 days). In addition there was no significant difference between short course (3-6 days) versus longer course (7-14 days) antibiotics. The methodological quality of the identified trials was poor and the optimal treatment duration could not be determined. We therefore need more appropriately designed randomized controlled trials testing the effect, - on clinical relevant outcomes -, of different treatment durations of a given antibiotic in a strictly defined population of elderly women.

Urinary tract infection: economic considerations

Urinary tract infection results in significant morbidity and mortality while consuming large amounts of national resources. The prevention, diagnosis, and treatment of urinary tract infection produce both costs and benefits, and economic analysis provides a rational framework for looking at these effects. The goals and methods of economic analysis in medicine are summarized, and strategies to address uncomplicated cystitis, nosocomial urinary tract infection, and pyelonephritis are reviewed, with an emphasis on the economic trade-offs faced by decision makers.

Short-term treatment of acute urinary tract infection in girls. Copenhagen Study Group of Urinary Tract Infections in Children

The efficiency of treatment of acute urinary tract infections with sulfamethizole for 3 days, sulfamethizole for 10 days, and pivmecillinam for 3 days was compared in a randomized multicentre study comprising 264 girls aged 1-15 years. For ethical reasons children with complicated diseases were not included. In these treatment groups no significant growth after treatment was found in 81%, 77%, and 74%, respectively (NS). New bacteria after treatment were found less frequently after sulfamethizole for 3 days (4%) when compared to sulfamethizole for 10 days (14%) and pivmecillinam for 3 days (13%) (p = 0.048). After pivmecillinam treatment 75% of new bacteria were Streptococcus faecalis versus 25% after sulfamethizole for 3 days and 18% after sulfamethizole for 10 days (p = 0.016). In the subgroup with nephro-urological abnormalities no significant growth after treatment was found in 68% of the sulfamethizole 3-day treated group, 54% of the sulfamethizole 10-day treated group, and 67% of the pivmecillinam 3-day treated group (NS). All treatments resulted in a change in the bacterial sensitivity pattern when bacteria isolated 1-10 days after treatment was compared to those found before treatment. This was more pronounced after the 10-day treatment when compared to the 3-day treatment. The sensitivity patterns of the bacteria isolated from recurrences were similar to those seen before treatment. After treatment there was no difference in the actuarial percentage recurrence-free curves of the 3 treatment groups. Side effects were rare in the sulfamethizole treated groups, and seen more often in the pivmecillinam treated group. 3-day treatment with sulfamethizole or alternatively pivmecillinam is recommended as first choice for treatment of uncomplicated acute urinary tract infections in girls.

Single dose and conventional treatment for acute bacterial and non-bacterial dysuria and frequency in general practice

A five day course of clavulanate-potentiated amoxicillin (Augmentin) has been compared with a single oral dose of fosfomycin trometamol in the treatment of patients complaining of symptoms suggesting urinary tract infection. The study took place in a single urban general practice of 15,000 patients in Cheshire. The microbiology was performed at a London Teaching Hospital. 141 patients entered the trial. 65 had a significant bacteriuria, 62 of which were assessable for the ability of the trial drugs to eradicate bacteriuria: 29 patients received clavulanate-potentiated amoxicillin and 33 fosfomycin trometamol. The cure rates, assessed at five to ten days and at four to six weeks post treatment, were 72% and 65%, respectively for clavulanate-potentiated amoxicillin and 85% and 81%, respectively for fosfomycin trometamol. Side effects, assessed in all 141 patients, occurred in 11.6% receiving clavulanate-potentiated amoxicillin and in 8.3% receiving fosfomycin. Statistically there is no difference between any of these findings and the effect of sample size is discussed. 69 patients were symptomatic but did not have a significant bacteriuria ("urethral syndrome"). These patients were assessed for the effect of treatment in relieving symptoms: 33 received fosfomycin trometamol and 36 clavulanate-potentiated amoxicillin. The success and speed of relieving the symptoms were very similar in the two groups. The finding that both groups responded equally well appears to refute an aetiological role for lactobacilli and diphtheroids in the "urethral syndrome", since these organisms are resistant to fosfomycin but sensitive to clavulanate-potentiated amoxicillin.

Ofloxacin versus trimethoprim-sulfamethoxazole for treatment of acute cystitis

We compared the safety and efficacies of ofloxacin and trimethoprim-sulfamethoxazole for the treatment of acute uncomplicated cystitis in women enrolled in a multicenter study. Data from three centers were combined for this report because the study design and study populations were identical, and patients were enrolled within an 18-month period. Cure rates for evaluable patients 4 weeks after treatment were high for all regimens: ofloxacin (200 mg) twice daily for 3 days, 22 of 25 (88%) cured; ofloxacin (200 mg) twice daily for 7 days, 42 of 49 (86%) cured; ofloxacin (300 mg) twice daily for 7 days, 25 of 25 (100%) cured; and trimethoprim-sulfamethoxazole (160/800 mg) twice daily for 7 days, 46 of 52 (88%) cured. Ofloxacin was more effective than trimethoprim-sulfamethoxazole in eradicating Escherichia coli from rectal cultures during and 1 week after treatment. Both ofloxacin and trimethoprim-sulfamethoxazole markedly reduced vaginal colonization with E. coli during and 4 weeks after therapy. Emergence of resistant coliforms in rectal flora was found in 5 (19%) of 27 patients treated with trimethoprim-sulfamethoxazole but none of 50 ofloxacin-treated patients who were studied (P = 0.004). Adverse effects were equally common among the four treatment groups. We conclude that 3 to 7 days of ofloxacin is as safe and effective as trimethoprim-sulfamethoxazole for treatment of uncomplicated cystitis in women and that ofloxacin effectively reduces the fecal and vaginal reservoirs of coliforms in such patients.

Double-blind comparison of 3-day versus 7-day treatment with norfloxacin in symptomatic urinary tract infections. The Inter-Nordic Urinary Tract Infection Study Group

The therapeutic efficacy and safety of norfloxacin 400 mg twice daily for 3 or 7 days was compared in a double-blind randomized multiclinic study including 485 female general practice patients with uncomplicated symptomatic lower urinary tract infections. 373 patients were considered valid for efficacy, 193 in the 3-day treatment group and 180 in the 7-day treatment group. The short-term efficacy (elimination of significant bacteriuria 3-13 days post-treatment) was 93.8% and 96.6% in the 3 and 7-day treatment groups, respectively, and the accumulated efficacy (elimination of significant bacteriuria 3 days post-treatment up until 45 days after the first dose) 81.3% and 91.7%, respectively (p less than 0.004). The median time to disappearance of symptoms was 3 days in both groups. Norfloxacin was well tolerated in both treatment groups.

Comparison of three- and ten-day regimens with a sulfadiazine-trimethoprim combination and pivmecillinam in acute lower urinary tract infections

132 female hospital employees (mean age 32 years) with uncomplicated, bacteriologically verified acute lower urinary tract infection were included in a randomized study. The patients were treated for 3 or 10 days with a sulfadiazine-trimethoprim combination (500 mg + 150 mg) b.i.d. or for 3 or 10 days with pivmecillinam (500 mg) t.i.d. The first follow-up evaluation was performed 3-5 days after the treatment. In both sulfadiazine-trimethoprim groups the cure rate was 97% and in both pivmecillinam groups 80%. This difference was mainly due to the occurrence of pivmecillinam-resistant Staphylococcus saprophyticus strains. 109 patients attended the second follow-up visit about 4 weeks after treatment. The prevalences of reinfections and relapses were 18% in both 3-day regimens and 4-7% in both 10-day regimens. No side-effects were reported in the 3-day sulfadiazine-trimethoprim group, while about 20% in the corresponding 10-day group had side-effects. Side-effects were not common in patients treated with pivmecillinam.

Cephalosporins in urinary tract infection

Despite their greater cost compared with other antibiotics, the cephalosporins continue to be used in the treatment of urinary tract infections. Most cephalosporins are excreted primarily by the kidney (by glomerular filtration, tubular secretion, or both) and urinary concentrations routinely exceed 1000 mg/L after even a small dose; exceptions include cefoperazone and ceftriaxone which both exhibit significant biliary excretion, and in patients with significant renal dysfunction only minimal concentrations of these drugs may be present in the urine. Although single-dose treatment of uncomplicated lower urinary tract infections with oral cephalosporins has not been as effective as with other antibiotics, cephalexin, cephradine and cefaclor continue to be used. Early clinical trials with cefuroxime axetil also appear promising for short term and single-dose therapy. The parenteral cephalosporins are reserved for use against more resistant strains or in hospitalised patients with upper urinary tract infections, their choice being directed by in vitro susceptibility tests. Newer agents such as ceftazidime and cefsulodin have been shown to be effective in infections due to P. aeruginosa. Recommended cephalosporin dosage regimens for the common urinary tract pathogens are given.

Ofloxacin versus trimethoprim-sulphamethoxazole in acute cystitis

The clinical and bacteriological efficacy and adverse reactions of ofloxacin vs trimethoprim-sulphamethoxazole were investigated in a double-blind, randomised study in 250 female patients (125 in each group) with acute, uncomplicated lower urinary tract infections. The dosages of ofloxacin and trimethoprim-sulphamethoxazole were 100mg and 160mg + 800mg twice daily, respectively. The duration of therapy was 3 days. 81% of the patients had significant bacteriuria. Escherichia coli was isolated in 76% and Staphylococcus saprophyticus in 11% of the infections. The bacteriological elimination, clinical cure and improvement rates of the evaluable patients on ofloxacin treatment were 92 and 95%, respectively. The corresponding figures on trimethoprim-sulphamethoxazole therapy were 88 and 90%. Adverse reactions were clinically unimportant, and none of the patients had to stop treatment. Mild and transient side effects, mainly from the gastrointestinal tract, central nervous system and skin, were reported by 19 and 22% of the patients in the ofloxacin and trimethoprim-sulphamethoxazole groups, respectively. None of the differences in clinical and bacteriological efficacy and side effects of ofloxacin vs trimethoprim-sulphamethoxazole were statistically significant. Ofloxacin appears to be an appropriate antibiotic for short term therapy of acute, uncomplicated, lower urinary tract infections, comparing favourably with trimethoprim-sulphamethoxazole treatment in this study.

Nalidixic acid and trimethoprim/sulphamethoxazole as alternatives for short-term treatment of urinary infections

The efficacy of 3-day therapy with nalidixic acid in 16 children, and trimethoprim/sulphamethoxazole in 19 children, was studied prospectively in children with an acute infection of the lower urinary tract and compared with that of a conventional 10-day course with the same drugs. The immediate cure rate was 97% in the 3-day group and 90% in the 10-day group. During 3 months of follow-up there were altogether six re-infections in children given short-term treatment and six in the conventionally treated group. The results give further support for the suggestion that 3-day therapy is equivalent to 10-day treatment in uncomplicated urinary infections in children and that both nalidixic acid and trimethoprim/sulphamethoxazole are good alternatives in such an approach.

Nalidixic acid and pivmecillinam for treatment of acute lower urinary tract infections

Women, 15-45 years of age, with symptoms of lower urinary tract infection (UTI) were randomly treated with nalidixic acid (1 g X 3) or pivmecillinam (200-400 mg X 3) for three or seven days, respectively. Therapeutic failure, relapse, or reinfection occurred among 18% of 82 women, even though the isolated strains of gram-negative rods in these patients were susceptible in vitro to the antibiotics used. Therapeutic failure, i.e. no effect or at best only a minor effect on the symptoms, was registered in 10 of 13 cases of UTI caused by Staphylococcus saprophyticus and treated with nalidixic acid, which was consistent with the high minimum inhibitory concentrations (MIC) (128-512 micrograms/ml) of this antibiotic. S. saprophyticus was isolated in 9 of 12 patients during treatment with nalidixic acid. On the other hand, pivmecillinam therapy was clinically effective in 16 of 18 patients with UTI caused by S. saprophyticus, even though the MIC of mecillinam to these strains was considerably higher (8-64 micrograms/ml) than that vis-à-vis gram-negative rods. Thus the clinical effect of pivmecillinam was significantly better than that of nalidixic acid in cases of UTI caused by S. saprophyticus. The organism was not isolated from 14 patients receiving pivmecillinam therapy.

Single-dose amoxycillin in the treatment of bacteriuria in pregnancy and the puerperium--a controlled clinical trial

Ninety obstetric patients with significant bacteriuria were treated randomly with either a single dose of 3 g amoxycillin or with a conventional course of ampicillin over 7 days. Treatment groups were comparable in terms of age, gravidity and socioeconomic status, and the outcome of pregnancy in the two groups did not differ significantly. Cure rates, assessed at 1 week and 6 weeks after treatment, were not significantly different: 88% for single-dose treatment and 84% for conventional treatment. It is concluded that a single dose of 3 g amoxycillin is a safe, effective and acceptable treatment for bacteriuria in pregnancy and the puerperium.

Cefadroxil once daily for three or seven days versus amoxycillin for seven days in uncomplicated urinary tract infections in women

The cure rate of acute uncomplicated urinary tract infection in general practice using 3 different treatment regimens, was studied in a randomized, multicenter trial. Patients were assigned to receive either cefadroxil 1 g once daily for 3 or 7 days or amoxycillin 375 mg t.i.d. for 7 days. 310 patients entered the study, of whom 230 could be evaluated according to the protocol. Two thirds of the cases were due to infections with Escherichia coli and about one fourth to Staphylococcus saprophyticus. No statistically significant differences in cure rates between the 3 regimens could be demonstrated neither at 1 week nor at 5 weeks of follow-up. The frequency of adverse reactions was low and similar in each treatment group.

Pharmacokinetics of nalidixic acid associated with sodium citrate

A pharmacokinetic study of sachets containing nalidixic acid (0.66 g) associated with sodium citrate (3.75 g)--NSC--was carried out in 10 healthy volunteers in order to determine the influence of the urine alcalinization due to sodium citrate on the elimination of nalidixic acid (NA) and its 7-hydroxy (HNA) and 7-carboxy (CNA) derivatives. Urine alcalinization enhanced markedly the urinary excretion of HNA, but not of NA and CNA. The urinary concentrations of bacteriologically active compounds--NA + HNA--remained above five times their minimum inhibitory concentration for 10 h following each dose. After a 3-day treatment using NSC three times daily there was no significant accumulation of NA and derivatives in the plasma and no significant change in their kinetics. Finally, from a pharmacokinetic viewpoint, the daily administration of 3 sachets of NSC each containing 0.66 g of NA seems valuable in the treatment of urinary tract infections.

Single-dose antibiotic therapy of urinary tract infection: is it appropriate in the emergency department?

Accurate diagnosis of urinary tract infection (UTI) is possible in the emergency department. Clinical differentiation of upper tract infection (pyelonephritis) from lower tract infection (cystitis) is difficult. The consequences of untreated UTI justify treatment by the emergency physician. Many treatment schemes are available. Single-dose antibiotic therapy is the preferred treatment method for uncomplicated UTI. It reduces compliance problems, effectively cures lower UTI, and provides for early identification of patients with more complex infection. The complications of this therapy are minimal.

A randomised comparison of single-dose vs. three-day and ten-day therapy with trimethoprim-sulfamethoxazole for acute cystitis in women

The efficacy of a single-dose (4 tablets) trimethoprim-sulfamethoxazole (TMP-SMX) was compared with that of a 3-day and 10-day treatment with TMP-SMX, 2 tablets twice daily, in 464 female out-patients with symptoms denoting acute, uncomplicated urinary tract infection (UTI). 321 patients (70%) had significant bacteriuria. Treatment effect could be assessed in 279 women. Comparable results were obtained with the 3 regimens 2 and 6 weeks after treatment. Eradication of the initial organism occurred in 96% with single-dose, in 96-94% with a 3-day, and in 98% with a 10-day course. The incidence of adverse reactions was significantly greater in patients treated with a 10-day (28%) than in those treated with a single-dose (5%), or 3-day (9%) regimen (p less than 0.01). This study suggests that short treatment regimens for uncomplicated UTI in women are as effective as and cause fewer side-effects than the conventional 10-day chemotherapy.

Treatment of urinary tract infections with varying regimens of sulfisoxazole

Four therapeutic regimens of sulfisoxazole were compared and contrasted with the antibody-coated bacteria test in patients with acute urinary tract infections. Of 158 college coeds who entered the study 146 completed the randomly assigned regimen. All 146 patients received 2 gm. sulfisoxazole initially and 1 gm. 4 times daily for 3 days in 44 patients (group 1), 7 days in 51 (group 2), 14 days in 29 (group 3) and 21 days in 22 (group 4). The presumptive sites of infection by the antibody-coated bacteria test were kidney (positive test) in 43 per cent of the patients and bladder (negative test) in 51.3 per cent. There was no correlation between the results of the antibody-coated bacteria test with either the presenting symptoms or the therapeutic responses. The bacteriologic cure rates at 2 days after therapy were 100 per cent in all groups and at 4 weeks after therapy they were 88.6 per cent in group 1, 86.3 per cent in group 2, 86.2 per cent in group 3 and 91 per cent in group 4. A 3-day course of sulfisoxazole was as effective as the longer regimens.

Effect of a three-day course of nalidixic acid in the frequency-dysuria syndrome with significant bacteriuria in women

The effect of a 3-day course of nalidixic acid was studied in 82 women, presenting with the dysuria-frequency syndrome and significant bacteriuria, mostly Escherichia coli sensitive to nalidixic acid. 62/76 patients (82%) that could be evaluated about 1 week after initiation of therapy were subjectively cured. Negative urinary cultures were found in 64/76 patients (84%). Two patients (2.4%) developed resistance to nalidixic acid. Bacteriological cure rate was 76% of 71 patients that could be controlled 1 month after the initiation of therapy. Nalidixic acid in the used granulate preparation initiated only mild side-effects.

Experience of three-day trimethoprim therapy for dysuria-frequency in primary health care

Dysuria-frequency in 78 patients was treated for 3 consecutive days with 300 mg trimethoprim administered in a single dose at night. Symptomatic cure was noted in 90% of the patients one week after initiation of therapy. In this investigation a positive urinary culture was found in 74% of the patients and bacteriological cure was obtained in all patients but one. A new infection was registered in 2 patients when controlled one week after the start of therapy. The isolated microorganisms were Escherichia coli in 52% of the cases and Staphylococcus saprophyticus in 29%. The high frequency of the latter offers an explanation to the low reliability of the nitrite dip test in diagnosing significant bacteriuria in this study.

Pivmecillinam in complicated urinary infections failing to respond to conventional therapy

Forty-three patients with a history of recurrent urinary infections, many of whom had renal involvement and had recently failed treatment, were then treated with pivmecillinam (400 mg 8-hourly for seven days). One week after the end of treatment the bacteriological cure rate was 72.1%. During the following four weeks, however, several of the cured patients relapsed, so that the cure rate five weeks after the end of treatment was only 46%. Thus, it is recommended that such patients should begin prophylactic treatment if found to be abacteriuric after the one week follow-up. Pivmecillinam was extremely well tolerated.

Trial of three-day and ten-day courses of amoxycillin in otitis media

A randomised double-blind controlled trial compared three-day and 10-day courses of amoxycillin (25 mg/kg daily) in children with otitis media. Seventeen doctors from five centres admitted 84 children between the ages of 2 and 10 years. Symptoms and signs were measured on admission to the trial, on day 3, and on day 15. Mother's observations were recorded daily for 10 days. Audiograms were performed at four and 12 weeks after the end of the trial. The treatment groups showed little difference in the speed of resolution of symptoms and signs, the numbers of primary treatment failures, or the frequency of recurrent ear infections. There were no complications in either group. Most children with otitis media can probably be successfully and safely treated with no more than a three-day course of amoxycillin providing their progress is reviewed about the fifth or sixth day after treatment started. This policy could save over 1 million pounds annually in antibiotic costs.

Duration of treatment of urinary tract infections

This review was stimulated by the current interest in use of single-dose therapy for uncomplicated "lower tract" infection in females and the potential benefit of long-term prophylaxis for patients with recurrent infections. Duration of therapy is only a tactic. It is dependent on understanding the natural history of urinary tract infections in relation to risk factors and the predictable response to treatment. Based on the pertinent literature, a series of elements are presented that define the current consensus concerning the definition, natural history and risk of renal damage from urinary tract infection. These are then considered in relation to the current diagnostic measures and procedures to localize infection. Single-dose therapy combined with bacteriologic monitoring appears to be a useful method to localize infection. Although it defines individuals who may require more prolonged treatment, it has not yet been shown to predict risk of renal damage or identify a subpopulation requiring further study. The major predictors of renal injury are anatomic and neurologic lesions that alter urine flow and host factors that decrease resistance to infection. These are currently better defined by individual patient characteristics and clinical observation than by localization studies. Long-term low-dose prophylaxis has been shown to be an effective means of management of highly recurrent episodes of infection. It does not, however, appear to prevent recurrences, after therapy has been discontinued, even after periods of prophylaxis as long as six months. Treatment should be based on reasonable expectancy of reduction in morbidity and/or renal damage.

Update on the treatment of bacterial urinary tract infections

The treatment of urinary tract infections (UTIs) has become a complex problem for the clinical practitioner. An understanding of the pharmacology, pharmacokinetics, and in vivo biological activity of antimicrobial agents is needed, as is an understanding of the variables that may influence patient compliance with medication regimens. Although UTIs are usually treated for 10 to 14 days, shorter treatment schedules of seven to ten days or even single-dose regimens are possible. Guidelines for the treatment of UTIs are presented along with suggestions for increased patient compliance.

Short-term treatment of lower urinary tract infections in children with trimethoprim/sulphadiazine

In a prospective study, 43 children between three months and 16 years of age and suffering from an acute infection of the lower urinary tract, were treated for either three or ten days with 4/16 mg trimethoprim/sulphadiazine/kgBW/day in two doses. Twenty-three were allotted to treatment for three days, whereas 20 were treated for ten days. Irrespective of the duration of therapy, the urine of all patients was sterile when urinary cultures were made three to seven days after the cessation of therapy. An early recurrence within the two months following the completion of treatment occurred in two children in each treatment group. In no case of recurrence was the organism resistant to trimethoprim/sulphadiazine. During a mean follow-up period of 11 months, 21.7% of the children treated for three days and 35% of those treated for ten days experienced a recurrence. The results suggest that children with an uncomplicated lower urinary tract infection can be successfully treated with a three-day course of trimethoprim/sulphadiazine in a conventional dosage.

A new citrated formulation of nalidixic acid (Mictral U.K.) for the treatment of acute cystitis

A 3-day course of a new citrated formulation of nalidixic acid (Mictral) was assessed in fifty-four women presenting with acute uncomplicated cystitis. Over 96% of women with a significant Gram-negative bacteriuria were cured of the infection following a course of treatment. Only two relapses occurred in this group during the follow-up period. Relief of symptoms occurred in nearly 90% of infected patients and generally by the second day of treatment. Although the incidence of side-effects was about 20% they were not considered serious.

Cinoxacin for treatment and prevention of recurrent urinary tract infection

Cinoxacin, an orally administered synthetic antimicrobial agent, is highly effective in the treatment of urinary tract caused by most urinary tract pathogens. Its high prolonged urinary concentration, low incidence of adverse reactions, low fecal concentration, infrequent induction of resistant bacterial strains, and broad antimicrobial spectrum are valuable attributes. Its efficacy for prolonged low-dose preventive therapy of frequently recurring infections adds to this new drug's importance.

A comparison of a 3-day course of Mictral with a 7-day course of ampicillin in the treatment of urinary tract infection

This general practice study compared a 3-day course of a new preparation, Mictral, with a standard 7-day course of ampicillin in the treatment of uncomplicated urinary tract infection. Mictral achieved bacteriological cure in all infected patients by Day 4 while only 69% of infected patients in the ampicillin group were abacteriuric by Day 8. Symptomatic relief and the incidence of side-effects were similar for both groups. It is concluded that Mictral appears to be a useful addition to currently available therapy for urinary tract infection and merits further investigation.

Single-dose antibiotic treatment: a new approach to lower urinary tract infections in primary care

Uncomplicated lower urinary tract infections are a common entity in family practice, yet their treatment is often unsatisfactory. Symptoms do not correlate well with bacteriology. Many patients are treated in the absence of bacteriological diagnosis. In those with known disease, compliance with therapy may be limited. These problems may be avoided by recourse to effective single-dose therapy with amoxicillin or trimethoprim-sulfamethoxazole.

Comparison of 4 and 10 days of doxycycline treatment for urinary tract infection

A total of 105 ambulatory patients presenting with symptoms suggestive of cystitis was allocated randomly to a 4 or a 10-day course of doxycycline therapy. Of these patients 62 (59 per cent) had documented infections and 41 (66 per cent) were infected with doxycycline-sensitive organisms: 24 were randomized to a 4-day course and 17 to a 10-day course of antibiotic. The groups were similar with respect to age, history of urinary tract infection, bacteriology and site of infection. Of the 4-day treatment group 90 per cent were free of infection 42 days after completion of therapy, compared to 92 per cent in the 10-day treatment group. Thus, patients with symptoms of cystitis may be treated with a short course of an appropriate antibiotic, provided careful followup is made 4 to 6 weeks after cessation of therapy. The site of urinary infection of doxycycline-resistant and sensitive organisms was determined by the antibody-coated bacteria techniques in 56 episodes: 13 (23 per cent) originated in kidneys, 34 (61 per cent) originated in bladder foci and the results in 9 (16 per cent) were indeterminate. Results of the antibody-coated bacteria technique did not predict therapeutic outcome.