Scientific and clinical challenges in the management of urinary tract infections

Antibiotic resistance in urinary isolates of Escherichia coli from college women with urinary tract infections

Of 176 urine isolates from female students positive for Escherichia coli, 29.6% were trimethoprim-sulfamethoxazole resistant and none were nitrofurantoin resistant. Among students with a history of urinary tract infection (UTI) (n = 119), resistance to ciprofloxacin was 11.8%, compared to 1.8% among those without prior UTI. Nitrofurantoin should be considered for empirical therapy of lower tract UTI.

Prevalence of virulence factors in Escherichia coli strains isolated from the genital tract of healthy cows

The prevalence of virulence genes expressing fimbriae, production of hemolysin, colicin and aerobactin, was determined in Escherichia coli isolates from healthy cow’s genital tract not showing clinical signs of infection. The presence of fimbriae expression genes (pap, sfa, afa) was assayed using specific primers in a polymerase chain reaction; none were detected in any of the isolates. Yet, a prevalence of 90.4%, 69.8%, and 28.5% of virulence factors for colicin, hemolysin and aerobactin respectively, was detected in the isolates. Analysis of the bacterial pathogenicity of isolates from the bovine genital tract may contribute towards the understanding of E. coli behavior.

The association between indwelling urinary catheter use in the elderly and urinary tract infection in acute care

Background

The use of indwelling urinary catheters (IUCs) is thought to be the most significant risk factor for developing nosocomial urinary tract infections (UTIs). However, it is unclear how many elderly patients have preexisting bacteriuria prior to IUC placement. The purpose of this study was to determine 1) the frequency and appropriateness of IUC use in the Emergency Department (ED) in elderly patients admitted to our acute care hospital, 2) the percentage of elderly patients with an IUC who were discharged from the hospital with a diagnosis of UTI, 3) the percentage of patients with IUCs who were diagnosed and treated for UTI in the ED or who had admission bacteriuria ≥10⁵ organisms/ml indicating preexisting UTI, and 4) the percentage of patients with no indication of UTI on admission who had inappropriately placed IUCs and subsequently were diagnosed with a UTI.

Methods

Retrospective chart review. Chi square used to test significance of differences in proportions.

Results

Seventy three percent of patients who received an IUC in the ED were elderly (≥65 years old). During the study period, 277 elderly patients received an IUC prior to admission. Of these, 77 (28%) were diagnosed with UTI during their hospitalization. Fifty three (69%) of those diagnosed with a UTI by discharge either had the UTI diagnosed in the ED or had bacteriuria ≥10⁵ organisms/ml prior to IUC placement. Of the 24 elderly patients who developed a catheter-associated UTI (i.e., 9% of the elderly population who received an IUC), 11 of the IUCs were placed inappropriately. Thus, 4% of elderly patients with no indication of UTI on admission who received an inappropriate IUC in the ED had a primary or secondary diagnosis of UTI by discharge. The overall rate of nosocomial UTI due to an inappropriately placed IUC was the same in males and females.

Conclusion

This study indicates that the strong association between IUC use and UTI may be partly explained by the high prevalence of preexisting UTI prior to IUC placement. Further prospective studies are needed to clarify the true risk vs benefit ratio for IUC use in acutely ill elderly patients.

Risk factors for bacteriuria due to Pseudomonas aeruginosa or Enterococcus spp in patients hospitalized via the emergency department

To determine the incidence and risk factors related to isolation of Pseudomonas aeruginosa or Enterococcus spp from urine cultures obtained from patients in the emergency department (ED), a 1-year prospective study was conducted of all urine specimens collected in the ED of a general hospital. Specimens from which one of these organisms was isolated at a concentration of >or=10(5) cfu/ml were included. Of 744 positive urine cultures, 39 (5%) were P. aeruginosa and 28 (4%) Enterococcus spp. Comparison with a control cohort of 80 patients with Escherichia coli bacteriuria revealed several univariate indicators for P. aeruginosa bacteriuria, including male sex, indwelling catheter, past prostatectomy, hospitalization in the previous 2 months and pregnancy; multivariate indicators were indwelling catheter (p<0.001) and male sex (p<0.001). Enterococcus and P. aeruginosa were significantly more often associated with asymptomatic bacteriuria. These data will help clinicians select appropriate antibiotic treatment for patients with urinary tract infections.

Virulence factors of uropathogenic Escherichia coli from a University Hospital in Ribeirão Preto, São Paulo, Brazil

The aim of the study was to determine the occurrence of virulence genes expressing fimbriae, production of hemolysin, colicin and aerobactin among a hundred Escherichia coli isolates obtained from in-and outpatients of a tertiary-care teaching hospital, between July and August 2000, showing clinical and laboratory signs of urinary tract infection (UTI). The presence of genes (pap, afa, sfa) for fimbriae expression was assayed using specific primers in a polymerase chain reaction. Among the isolates studied, the prevalence of the virulence factors was 96.0%, 76.0%, 24.0%, for hemolysin, aerobactin and colicin, respectively; the prevalence of genes coding for fimbrial adhesive systems was 32.0%, 19.0% and 11.0% for pap, sfa and afa respectively. The strains isolated from the outpatients displayed a greater number of virulence factors compared to those from hospitalized subjects, emphasizing the difference between these two kinds of patients.

Fosfomycin tromethamine in uncomplicated urinary tract infections: a clinical study

The aim of our study was to verify if the empiric therapy with a single dose of 3 g fosfomycin tromethamine in patients with uncomplicated urinary tract infections (UTIs) was able to clinically resolveand to microbiologically eradicate the infection. A total of 387 out of the 400 patients (274 cases with acute and 113 cases with recurrent uncomplicated UTIs) were enrolled in the clinical study. Clinical and microbiological assessments were performed before and at 8-10 days after the administration. At follow-up high clinical recovery (88.9%) and bacteriological (94.9%) eradication rates were achieved. Gastrointestinal side effects were found in only 4.3% of patients. In conclusion, a single-dose administration regimen of fosfomycin tromethamine should be encouraged as a first choice of drug therapy for uncomplicated UTIs.

Laboratory diagnosis of urinary tract infections in adult patients

Urinary tract infections (UTIs) are among the most common bacterial infections and account for a significant part of the workload in clinical microbiology laboratories. Enteric bacteria (in particular, Escherichia coli) remain the most frequent cause of UTIs, although the distribution of pathogens that cause UTIs is changing. More important is the increase in resistance to some antimicrobial agents, particularly the resistance to trimethoprim-sulfamethoxazole seen in E. coli. Physicians distinguish UTIs from other diseases that have similar clinical presentations with use of a small number of tests, none of which, if used individually, have adequate sensitivity and specificity. Among the diagnostic tests, urinalysis is useful mainly for excluding bacteriuria. Urine culture may not be necessary as part of the evaluation of outpatients with uncomplicated UTIs, but it is necessary for outpatients who have recurrent UTIs, experience treatment failures, or have complicated UTIs, as well as for inpatients who develop UTIs.

Urinary tract infections in women

Urinary tract infections in female patients are exceedingly common. One third of all women with an initial UTI demonstrate recurrence, and one third of those recurrences are in the first 6 months. The potential morbidity of RUTIs is high, especially in infants, the elderly, and pregnant patients. Uropathogenic bacteria reside in the rectal vault, colonize the vagina, and then ascend per the urethra into the bladder. These bacteria avidly adhere to uroepithelial cells using pili and can further ascend to the kidneys. Empiric treatment of an initial uncomplicated UTI is acceptable, but recurrences warrant a urine culture and possible radiographic evaluation. Fluoroquinolones are now first-line medications for UTIs, except in geographic areas where resistance to TMP-SMX is still low. Response to therapy should govern the need for additional treatment. Certain motivated patients with three or more UTIs per year should be considered for prophylaxis therapy.

Management of UTIs During Pregnancy

This article summarizes the pathophysiology, patient presentation, diagnostic testing, and current treatment modalities for pregnant women presenting with urinary tract symptoms in pregnancy. Urinary tract infection is a common health problem, affecting millions of people each year. However, this seemingly benign condition may have serious consequences if it occurs during the course of a woman's pregnancy, and if untreated could lead to pyelonephritis, preterm labor, or Group B Streptococcal infection in the newborn. Thus, the prevention, early detection, and prompt treatment of urinary tract infections in pregnancy have become essential components of prenatal care.

Urinary tract infection in women--physician's preferences for treatment and adherence to guidelines: a national drug utilization study in a managed care setting

BACKGROUND

The treatment of urinary tract infection (UTI), the most common bacterial infection in most Western countries, is a global clinical and economic issue. Trimethoprim-sulfamethoxazole (TMP-SMX) and nitrofurantoin are the two drugs currently recommended in clinical guidelines in Israel for uncomplicated UTI in women.

OBJECTIVES

This study evaluates physician preferences for treatment and adherence to guidelines.

METHOD

Data were derived from the electronic records of Leumit Health Fund, one of four health management organizations in Israel. Non-pregnant women aged 18-75 years with a diagnosis of acute cystitis or UTI without risk factors for complicated UTI who were empirically treated with antibiotics from January 2001 to June 2002 were identified. The final sample comprised 7738 physician-patient encounters. Physician prescription behavior was analyzed by evaluating the proportion of treatments with each individual drug. A binary regression model was implemented to identify factors associated with suboptimal adherence to the guidelines.

RESULTS

TMP-SMX was the most frequently prescribed drug (25.81%), followed by nitrofurantoin (14.71%), for a 40.52% rate of adherence to the guidelines [95% confidence interval (CI)=39.42, 41.61]. Drugs from the fluoroquinolone family were prescribed in 22.82% of cases. Prescription behavior was also influenced by non-clinical, non-pharmacological factors, such as physician specialty, geographic setting and patient age.

CONCLUSIONS

The majority of cases of UTI in the present study were not treated according to the current guidelines. Fluoroquinolones, though not recommended and relatively costly, were prescribed extensively. These results highlight the necessity for a remedial education program within the health care system designed to improve adherence to the guidelines for the treatment of UTI in women. As this issue is of global importance, this evaluation may serve as a model for similar studies in other settings or countries.