Evaluation of and antimicrobial therapy for recurrent urinary tract infections in women

Urinary Biomarkers: Diagnostic Tools for Monitoring Athletes' Health Status

Acute or intense exercise is sometimes related to infections of the urinary tract. It can also lead to incorrect hydration as well as incorrect glomerular filtration due to the presence of high-molecular-weight proteins that cause damage to the kidneys. In this context, our study lays the foundations for the use of a urine test in a team of twelve male basketball players as a means of monitoring numerous biochemical parameters, including pH, specific weight, color, appearance, presence of bacterial cells, presence of squamous cells, leukocytes, erythrocytes, proteins, glucose, ketones, bilirubin, hemoglobin, nitrite, and leukocyte esterase, to prevent and/or treat the onset of pathologies, prescribe personalized treatments for each athlete, and monitor the athletes’ health status.

Personal clinical history predicts antibiotic resistance of urinary tract infections

Antibiotic resistance is prevalent among the bacterial pathogens causing urinary tract infections. However, antimicrobial treatment is often prescribed “empirically”, in the absence of antibiotic susceptibility testing, risking mismatched and therefore ineffective treatment. Here, linking a 10-year longitudinal dataset of over 700,000 community-acquired UTIs with over 5,000,000 individually-resolved records of antibiotic purchases, we identify strong associations of antibiotic resistance with the demographics, records of past urine cultures and history of drug purchases of the patients. When combined together, these associations allow for machine learning-based personalized drug-specific predictions of antibiotic resistance, thereby enabling drug-prescribing algorithms that match antibiotic treatment recommendation to the expected resistance of each sample. Applying these algorithms retrospectively, over a one-year test period, we find that they much reduce the risk of mismatched treatment compared to the current standard-of-care. The clinical application of such algorithms may help improve the effectiveness of antimicrobial treatments.

No. 250-Recurrent Urinary Tract Infection

OBJECTIVE

To provide an update of the definition, epidemiology, clinical presentation, investigation, treatment, and prevention of recurrent urinary tract infections in women.

OPTIONS

Continuous antibiotic prophylaxis, post-coital antibiotic prophylaxis, and acute self-treatment are all efficient alternatives to prevent recurrent urinary tract infection. Vaginal estrogen and cranberry juice can also be effective prophylaxis alternatives.

EVIDENCE

A search of PubMed and The Cochrane Library for articles published in English identified the most relevant literature. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date restrictions.

VALUES

This update is the consensus of the Sub-Committee on Urogynaecology of the Society of Obstetricians and Gynaecologists of Canada. Recommendations were made according to the guidelines developed by the Canadian Task Force on Preventive Health Care (Table 1).

OPTIONS

Recurrent urinary tract infections need careful investigation and can be efficiently treated and prevented. Different prophylaxis options can be selected according to each patient's characteristics.

RECOMMENDATIONS

A 6-year study of complicated urinary tract infections in southern China: prevalence, antibiotic resistance, clinical and economic outcomes

Urinary tract infections (UTIs) are common nosocomial infections. This study evaluated the prevalence, pathogens, antibiotic resistances, clinical outcomes, and hospitalization costs associated with complicated UTIs in southern China, and risk factors delaying patient discharge. We retrospectively reviewed electronic medical records of 4,284 (61.4% women) complicated UTI-related hospitalizations from 2008 to 2013. Average patient age was 61.1 years and median hospital stay was 11 days. Pathogens were isolated from 1,071 urine and 148 blood specimens. Gram-negative bacteria were the most frequent and included Escherichia coli (48.2%), Klebsiella pneumoniae (9.5%), Pseudomonas aeruginosa (4.9%), and Proteus mirabilis (4.6%), while Enterococcus spp. (14.4%) was the most common Gram-positive bacteria causing UTIs. Both E. coli and K. pneumoniae showed high resistance rates (>45%) to wide-spectrum penicillins, cephalosporins, aztreonam, and ciprofloxacin. Resistances to beta-lactamase inhibitor/beta-lactam antibiotic combination were relatively lower. Imipenem, meropenem, and amikacin had the greatest activity against E.coli and K. pneumoniae. Recurrent infection was a risk factor for mortality. Age, sex, previous surgery, diabetes, and renal insufficiency were significant risk factors for delayed discharge (P<0.01). Response to initial treatment was associated with a lower cost. Initial empiric use of antibiotics least associated with resistance may reduce costs and medical resource usage.

The Vaginal Microbiota and Urinary Tract Infection

The vagina is a key anatomical site in the pathogenesis of urinary tract infection (UTI) in women, serving as a potential reservoir for infecting bacteria and a site at which interventions may decrease the risk of UTI. The vaginal microbiota is a dynamic and often critical factor in this pathogenic interplay, because changes in the characteristics of the vaginal microbiota resulting in the loss of normally protective Lactobacillus spp. increase the risk of UTI. These alterations may result from the influence of estrogen deficiency, antimicrobial therapy, contraceptives, or other causes. Interventions to reduce adverse effects on the vaginal microbiota and/or to restore protective lactobacilli may reduce the risks of UTI.

Clinical significance of video-urodynamic in female recurrent urinary tract infections

Purpose

We aimed to assess the value of video-urodynamic study (VUD) in the identification of lower urinary tract voiding dysfunction in female recurrent urinary tract infections (UTIs).

Patients and methods

A total of 54 women with recurrent UTIs who underwent VUDs between 2013 and 2015 were analyzed. They were carefully evaluated by complete history, voiding diary, physical investigation, urosonography, and VUDs.

Results

Neurogenic and non-neurogenic voiding dysfunctions were found in 4% and 63% of women respectively. Detrusor sphincter dyssynergia, detrusor underactivity, and a combination of both were found in 17% (nine of 54), 22% (12 of 54), and 11% (six of 54) of women, respectively. Overactive bladder syndrome was determined in 28% (15 of 54) of women. Reduction in the maximal urinary flow rate to less than 15 mL/s and post-void residual volume were revealed in 63% (34 of 54) and 54% (29 of 54) of women, respectively. Stress urinary incontinence was noticed in 39% (21 of 54) of women with a median pad usage of three pads (range: 1–15) daily. Urgency and nocturia were complaints in 54% (29 of 54) and 43% (23 of 54) of women, respectively. The median voiding frequency and nocturia episodes were 7±4 (1–13) and 1±3 (0–12), respectively.

Conclusion

Dysfunctional voiding can encourage the formation of recurrent UTIs in the female. The VUDs are the investigation of choice to diagnose voiding dysfunction.

Effectiveness of Preanalytic Practices on Contamination and Diagnostic Accuracy of Urine Cultures: a Laboratory Medicine Best Practices Systematic Review and Meta-analysis

BACKGROUND

Urinary tract infection (UTI) in the United States is the most common bacterial infection, and urine cultures often make up the largest portion of workload for a hospital-based microbiology laboratory. Appropriately managing the factors affecting the preanalytic phase of urine culture contributes significantly to the generation of meaningful culture results that ultimately affect patient diagnosis and management. Urine culture contamination can be reduced with proper techniques for urine collection, preservation, storage, and transport, the major factors affecting the preanalytic phase of urine culture.

OBJECTIVES

The purposes of this review were to identify and evaluate preanalytic practices associated with urine specimens and to assess their impact on the accuracy of urine culture microbiology. Specific practices included collection methods for men, women, and children; preservation of urine samples in boric acid solutions; and the effect of refrigeration on stored urine. Practice efficacy and effectiveness were measured by two parameters: reduction of urine culture contamination and increased accuracy of patient diagnosis. The CDC Laboratory Medicine Best Practices (LMBP) initiative's systematic review method for assessment of quality improvement (QI) practices was employed. Results were then translated into evidence-based practice guidelines.

SEARCH STRATEGY

A search of three electronic bibliographic databases (PubMed, SCOPUS, and CINAHL), as well as hand searching of bibliographies from relevant information sources, for English-language articles published between 1965 and 2014 was conducted.

SELECTION CRITERIA

The search contained the following medical subject headings and key text words: urinary tract infections, UTI, urine/analysis, urine/microbiology, urinalysis, specimen handling, preservation, biological, preservation, boric acid, boric acid/borate, refrigeration, storage, time factors, transportation, transport time, time delay, time factor, timing, urine specimen collection, catheters, indwelling, urinary reservoirs, continent, urinary catheterization, intermittent urethral catheterization, clean voided, midstream, Foley, suprapubic, bacteriological techniques, and microbiological techniques.

MAIN RESULTS

Both boric acid and refrigeration adequately preserved urine specimens prior to their processing for up to 24 h. Urine held at room temperature for more than 4 h showed overgrowth of both clinically significant and contaminating microorganisms. The overall strength of this body of evidence, however, was rated as low. For urine specimens collected from women, there was no difference in rates of contamination for midstream urine specimens collected with or without cleansing. The overall strength of this evidence was rated as high. The levels of diagnostic accuracy of midstream urine collection with or without cleansing were similar, although the overall strength of this evidence was rated as low. For urine specimens collected from men, there was a reduction in contamination in favor of midstream clean-catch over first-void specimen collection. The strength of this evidence was rated as high. Only one study compared midstream collection with cleansing to midstream collection without cleansing. Results showed no difference in contamination between the two methods of collection. However, imprecision was due largely to the small event size. The diagnostic accuracy of midstream urine collection from men compared to straight catheterization or suprapubic aspiration was high. However, the overall strength of this body of evidence was rated as low. For urine specimens collected from children and infants, the evidence comparing contamination rates for midstream urine collection with cleansing, midstream collection without cleansing, sterile urine bag collection, and diaper collection pointed to larger reductions in the odds of contamination in favor of midstream collection with cleansing over the other methods of collection. This body of evidence was rated as high. The accuracy of diagnosis of urinary tract infection from midstream clean-catch urine specimens, sterile urine bag specimens, or diaper specimens compared to straight catheterization or suprapubic aspiration was varied.

AUTHORS' CONCLUSIONS

No recommendation for or against is made for delayed processing of urine stored at room temperature, refrigerated, or preserved in boric acid. This does not preclude the use of refrigeration or chemical preservatives in clinical practice. It does indicate, however, that more systematic studies evaluating the utility of these measures are needed. If noninvasive collection is being considered for women, midstream collection with cleansing is recommended, but no recommendation for or against is made for midstream collection without cleansing. If noninvasive collection is being considered for men, midstream collection with cleansing is recommended and collection of first-void urine is not recommended. No recommendation for or against is made for collection of midstream urine without cleansing. If noninvasive collection is being considered for children, midstream collection with cleansing is recommended and collection in sterile urine bags, from diapers, or midstream without cleansing is not recommended. Whether midstream collection with cleansing can be routinely used in place of catheterization or suprapubic aspiration is unclear. The data suggest that midstream collection with cleansing is accurate for the diagnosis of urinary tract infections in infants and children and has higher average accuracy than sterile urine bag collection (data for diaper collection were lacking); however, the overall strength of evidence was low, as multivariate modeling could not be performed, and thus no recommendation for or against can be made.

Role of duration of catheterization and length of hospital stay on the rate of catheter-related hospital-acquired urinary tract infections

Objective

Our aim is to prove that duration of catheterization and length of hospital stay (LOS) are associated with the rate of hospital-acquired urinary tract infections (UTI), while taking into account type of urinary catheter used, the most common organisms found, patient diagnosis on admission, associated comorbidities, age, sex, precautions that should be taken to avoid UTI, and comparison with other studies.

Methods

The study was done in a university teaching hospital with a 920-bed capacity; this hospital is a tertiary care center in Riyadh, Saudi Arabia. The study was done on 250 selected patients during the year 2010 as a retrospective descriptive study. Patients were selected as purposive sample, all of them having been exposed to urinary catheterization; hospital-acquired UTI were found in 100 patients. Data were abstracted from the archived patients’ files in the medical record department using the annual infection control logbook prepared by the infection control department. The data collected were demographic information about the patients, clinical condition (diagnosis and the LOS), and possible risk factors for infection such as duration of catheterization, exposure to invasive devices or surgical procedures, and medical condition.

Results

There was a statistically significant association between the rate of UTI and duration of catheterization: seven patients had UTI out of 46 catheterized patients (15%) at 3 days of catheterization, while 30 patients had UTI out of 44 catheterized patients (68%) at 8 days of catheterization (median 8 days in infected patients versus 3 days in noninfected patients; P-value <0.05), which means that the longer the duration of catheterization, the higher the UTI rate. There was a statistically significant association between the rate of UTI and LOS: three patients had UTI out of 37 catheterized patients (8%) at 10 days LOS, while 42 patients had UTI out of 49 catheterized patients (85.7%) at 18 days LOS. The longer the LOS, the higher the UTI rate: LOS for each patient (median 18 days for infected patients versus 10 days for noninfected patients; P-value <0.05), and number of hospital-acquired catheter-related UTI (100 patients had UTI out of 250 catheterized patients, P=0.04).

Conclusion

Reduction of the duration of catheterization and LOS of the patient have a positive impact in reduction of catheter-related UTI.

Characteristics of urinary tract infection pathogens and their in vitro susceptibility to antimicrobial agents in China: data from a multicenter study

OBJECTIVE

This study assessed the characteristics of pathogens identified in clinical isolates from patients with urinary tract infection (UTI) and their in vitro sensitivity to commonly used antibiotics in the clinical setting in China.

DESIGN AND SETTING

Multicenter study was conducted between January and December 2011 in 12 hospitals in China.

PARTICIPANTS

Urine samples were collected from 356 symptomatic patients treated in the study hospitals for acute uncomplicated cystitis, recurrent UTI or complicated UTI.

PRIMARY AND SECONDARY OUTCOME MEASURES

Minimal inhibitory concentrations (MICs) were measured using broth microdilution according to the Clinical and Laboratory Standards Institute 2011 guidelines. Thirteen antimicrobial agents were tested: fosfomycin tromethamine, levofloxacin, moxifloxacin, cefdinir, cefixime, cefaclor, cefprozil, cefuroxime, amoxicillin/clavulanic acid, cefotaxime, azithromycin, nitrofurantoin and oxacillin. Escherichia coli isolates were screened and extended spectrum β-lactamases (ESBL) production was confirmed by a double-disk synergy test.

RESULTS

198 urine samples were culture-positive and 175 isolates were included in the final analysis. E coli was detected in 50% of cultures, followed by Staphylococcus epidermidis (9%), Enterococcus faecalis (9%) and Klebsiella pneumoniae (5%). The detection rate of ESBL-producing E coli was 53%. Resistance to levofloxacin was the most common among all the isolates. Nitrofurantoin and fosfomycin tromethamine had the greatest activity against E coli; overall, 92% and 91% of isolates were susceptible to these antimicrobials. E faecalis had the highest susceptibility rates to fosfomycin tromethamine (100%).

CONCLUSIONS

The most frequently identified pathogens in our patients were ESBL-producing E coli and E faecalis. Fosfomycin tromethamine and nitrofurantoin showed a good antimicrobial activity against UTI pathogens. They may represent good options for the empiric treatment of patients with UTI.

Recurrent Urinary Tract Infections Management in Women: A review

Urinary tract infections (UTIs) are one of the most frequent clinical bacterial infections in women, accounting for nearly 25% of all infections. Around 50-60% of women will develop UTIs in their lifetimes. Escherichia coli is the organism that causes UTIs in most patients. Recurrent UTIs (RUTI) are mainly caused by reinfection by the same pathogen. Having frequent sexual intercourse is one of the greatest risk factors for RUTIs. In a subgroup of individuals with coexisting morbid conditions, complicated RUTIs can lead to upper tract infections or urosepsis. Although the initial treatment is antimicrobial therapy, use of different prophylactic regimens and alternative strategies are available to reduce exposure to antibiotics.

Management of urinary tract infections in the era of increasing antimicrobial resistance

Antimicrobial resistance of urinary pathogens is increasing. Most urinary tract infections (UTIs) should still be treated empirically. However, patients with recurrence or other risk factors for resistance may benefit from urine culture. Patients with recurrent UTI often resort to antibiotic prevention, a risky proposition in terms of resistance. Non-antimicrobial preventative methods should be considered first. If preventative antibiotics must be used, postcoital patient-initiated protocols are effective and reduce overall antibiotic exposure compared with continuous prophylaxis. Consider referring patients for urologic evaluation when at risk for complicated UTIs or when recurrence continues despite conservative interventions.

Recurrent uncomplicated urinary tract infections in women: a review

Recurrent urinary tract infections most often present with symptoms of irritative voiding. In most cases, they are caused by reinfection with a previously isolated organism. Patients with one or more symptoms of uncomplicated recurrent urinary tract infection should undergo thorough examination and screening for underlying comorbidities that increase susceptibility. When frequent reinfections, empiric treatment relapse, persistent infections, or risk factors for complicated infections are encountered, patients may benefit from urodynamics, cystoscopy, renal ultrasound, intravenous urogram, or voiding cystourethrogram to evaluate for anatomic, functional, or metabolic abnormalities affecting the urinary tract (e.g., stones, stricture, obstruction, vesicoureteral reflux, lesions, detrusor underactivity). These patients may benefit from culture-guided empiric treatment and further evaluation by urology, nephrology, or infectious disease specialists. In patients with a history of uncomplicated urinary tract infections, empiric treatment guided by local antimicrobial resistance may efficiently treat a suspected recurrence. After successful treatment of the acute infection, postcoital prophylaxis, continuous prophylaxis, or self-start empiric treatment may be selected based on frequency of recurrent infections, temporal relation to intercourse, and patient characteristics. Ancillary measures such as probiotics, cranberry products, or local estrogen replacement may also be considered. This article will review the current definition, epidemiology, pathogenesis, diagnosis, work-up, treatment, treatment side effects, and prevention of recurrent urinary tract infections in women. A suggested algorithm for evaluation and treatment based on current literature is provided.

Nitrofurantoin compares favorably to recommended agents as empirical treatment of uncomplicated urinary tract infections in a decision and cost analysis

OBJECTIVE

To analyze the costs of nitrofurantoin use compared to those of other antibiotics recommended for treatment of uncomplicated urinary tract infection (UTI).

PATIENTS AND METHODS

We used a decision analysis model to perform cost-minimization and sensitivity analyses to determine the level of trimethoprim-sulfamethoxazole (TMP-SMX) and fluoroquinolone resistance that would favor the use of nitrofurantoin as a first-line empirical treatment of uncomplicated UTIs. The model used a program perspective to evaluate costs.

RESULTS

Nitrofurantoin was cost-minimizing when the prevalence of fluoroquinolone resistance exceeded 12% among uropathogens or the prevalence of TMP-SMX resistance exceeded 17%. On 2-way sensitivity analysis, variables that had a significant impact on our cost-minimization threshold included cost of antibiotics and probability of clinical cure with antibiotics.

CONCLUSION

From a payer perspective, nitrofurantoin appears to be a reasonable alternative to TMP-SMX and fluoroquinolones for empirical treatment of uncomplicated UTIs, especially given the current prevalence of antibiotic resistance among community uropathogens. On the basis of efficacy, cost, and low impact on promoting antimicrobial resistance, clinicians should consider nitrofurantoin as a reasonable alternative to TMP-SMX and fluoroquinolones for first-line therapy for uncomplicated UTIs.

Randomized, placebo-controlled phase 2 trial of a Lactobacillus crispatus probiotic given intravaginally for prevention of recurrent urinary tract infection

BACKGROUND

Urinary tract infections (UTIs) are common among women and frequently recur. Depletion of vaginal lactobacilli is associated with UTI risk, which suggests that repletion may be beneficial. We conducted a double-blind placebo-controlled trial of a Lactobacillus crispatus intravaginal suppository probiotic (Lactin-V; Osel) for prevention of recurrent UTI in premenopausal women.

METHODS

One hundred young women with a history of recurrent UTI received antimicrobials for acute UTI and then were randomized to receive either Lactin-V or placebo daily for 5 d, then once weekly for 10 weeks. Participants were followed up at 1 week and 10 weeks after intervention and for UTIs; urine samples for culture and vaginal swabs for real-time quantitative 16S ribosomal RNA gene polymerase chain reaction for L. crispatus were collected.

RESULTS

Recurrent UTI occurred in 7/48 15% of women receiving Lactin-V compared with 13/48 27% of women receiving placebo (relative risk [RR], .5; 95% confidence interval, .2-1.2). High-level vaginal colonization with L. crispatus (≥10(6) 16S RNA gene copies per swab) throughout follow-up was associated with a significant reduction in recurrent UTI only for Lactin-V (RR for Lactin-V, .07; RR for placebo, 1.1; P < .01).

CONCLUSIONS

Lactin-V after treatment for cystitis is associated with a reduction in recurrent UTI. Larger efficacy trials of this novel preventive method for recurrent UTI are warranted. CLINICAL TRIALS REGISTRATION. NCT00305227.

Recurrent urinary tract infection

OBJECTIVE

to provide an update of the definition, epidemiology, clinical presentation, investigation, treatment, and prevention of recurrent urinary tract infections in women.

OPTIONS

continuous antibiotic prophylaxis, post-coital antibiotic prophylaxis, and acute self-treatment are all efficient alternatives to prevent recurrent urinary tract infection. Vaginal estrogen and cranberry juice can also be effective prophylaxis alternatives.

EVIDENCE

a search of PubMed and The Cochrane Library for articles published in English identified the most relevant literature. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date restrictions.

VALUES

this update is the consensus of the Sub-Committee on Urogynaecology of the Society of Obstetricians and Gynaecologists of Canada. Recommendations were made according to the guidelines developed by the Canadian Task Force on Preventive Health Care (Table 1).

OPTIONS

recurrent urinary tract infections need careful investigation and can be efficiently treated and prevented. Different prophylaxis options can be selected according to each patient's characteristics.

Urothelial cultures support intracellular bacterial community formation by uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) causes most community-acquired and nosocomial urinary tract infections (UTI). In a mouse model of UTI, UPEC invades superficial bladder cells and proliferates rapidly, forming biofilm-like structures called intracellular bacterial communities (IBCs). Using a gentamicin protection assay and fluorescence microscopy, we developed an in vitro model for studying UPEC proliferation within immortalized human urothelial cells. By pharmacologic manipulation of urothelial cells with the cholesterol-sequestering drug filipin, numbers of intracellular UPEC CFU increased 8 h and 24 h postinfection relative to untreated cultures. Enhanced UPEC intracellular proliferation required that the urothelial cells, but not the bacteria, be filipin treated prior to infection. However, neither UPEC frequency of invasion nor early intracellular trafficking events to a Lamp1-positive compartment were modulated by filipin. Upon inspection by fluorescence microscopy, cultures with enhanced UPEC intracellular proliferation exhibited large, dense bacterial aggregates within cells that resembled IBCs but were contained with Lamp1-positive vacuoles. While an isogenic fimH mutant was capable of forming these IBC-like structures, the mutant formed significantly fewer than wild-type UPEC. Similar to IBCs, expression of E. coli iron acquisition systems was upregulated by intracellular UPEC. Expression of other putative virulence factors, including hlyA, cnf1, fliC, kpsD, and the biofilm adhesin yfaL also increased, while expression of fimA decreased and that of flu did not change. These results indicate that UPEC differentially regulates virulence factors in the intracellular environment. Thus, immortalized urothelial cultures that recapitulate IBC formation in vitro represent a novel system for the molecular and biochemical characterization of the UPEC intracellular life cycle.

Differences in physician and patient perceptions of uncomplicated UTI symptom severity: understanding the communication gap

Uncomplicated urinary tract infection (uUTI) is the most common bacterial infection encountered in clinical practice but evaluation and treatment of the illness vary considerably among physicians. The literature suggests that there is often a gap in the perception of symptom severity between physician and patient, a gap that may be a result of the different models they use to explain and manage disease, a result of misinformation or misconceptions about uUTIs, or a result of poor patient-physician communication. This gap in perceptions about uUTI may lead to poor patient care, decreased quality of life and increased antibiotic resistance. Good communication between patient and physician has been shown to result in improved health outcomes. Several approaches to improving communication during consultations have been described in the literature. Physician and patient education and their agreement about any disease, including uUTI can be expected to improve treatment compliance and reduce the incidence of recurrence of such infections. Future work should focus on improvement of communication during clinical consultations to encourage appropriate bidirectional sharing of clinical and patient information. Further research about behavioural risk factors for uUTI may allow evidence-based information to be used in educational programmes.

Antigen-specific responses accelerate bacterial clearance in the bladder

Urinary tract infections (UTIs) cause patient morbidity and have a substantial economic impact. Half of all women will suffer a UTI at least once, and 25% of these women will have recurrent infections. That 75% of previously infected women do not become reinfected strongly suggests a role for an adaptive immune response. The goal of this study was to characterize the adaptive immune responses to uropathogenic Escherichia coli (UPEC), the predominant uropathogen. A novel murine model of UTI reinfection was developed using the prototypic cystitis UPEC isolate NU14 harboring a plasmid encoding OVA as a unique antigenic marker. Bacterial colonization of the bladder was quantified following one or more infections with NU14-OVA. Animals developed anti-OVA serum IgG and IgM titers after the initial infection and marked up-regulation of activation markers on splenic T cells. We observed a 95% reduction in bacterial colonization upon reinfection, and splenic leukocytes showed Ag-specific proliferation in vitro. Adoptive transfer of splenic T cells or passive transfer of serum from previously infected mice protected naive syngeneic mice from UPEC colonization. These findings support our hypothesis that adaptive immune responses to UPEC protect the bladder from reinfection and form the basis of understanding susceptibility to recurrent UTI in women.

Reclassification of Urinary Tract Infections in Critically Ill Trauma Patients: A Time-Dependent Analysis

BACKGROUND

Successful treatment of urinary tract infections (UTIs) in the trauma ICU requires early recognition and timely, appropriate antibiotic therapy. We evaluated the incidence and microbiology of UTIs stratified by days post-admission and risk factors.

METHODS

Prospective data were collected on 1,172 trauma patients admitted to the ICU over a two-year period. Infections were classified as Community Acquired (CA, < or = 3 days), Early Nosocomial (EN, 4-6 days), Mid-Nosocomial (MN, 7-10 days) and Late Nosocomial (LN > 10 days). Criteria of the U.S. Centers for Disease Control and Prevention (CDC) were used for diagnosis.

RESULTS

Two hundred twenty patients (19%) were diagnosed with a total of 235 UTIs. Thirtysix patients were diagnosed with multiple UTIs. Escherichia coli, Enterococcus sp. and Candida sp. were the most common pathogens isolated. One thousand one hundred fifty-one patients had a Foley catheter placed (mean duration, 1 +/- 11 days) with a CDC device-related infection rate (no. of catheter-associated UTIs/1000 catheter days) of 18. Patients admitted with a CA infection were significantly older (p < 0.001) and had a higher mortality rate (39% vs. 15%, p = 0.001). Unanticipated pathogens in this group included Enterococcus, Candida, and Pseudomonas. Women were more likely to be admitted with a CA infection (5% vs. 1%, p < 0.001) or acquire an NI infection (23% vs. 15%, p < 0.001). Obesity was highly predictive of increased Foley catheter days, and thus UTI, by multivariate analysis (p < 0.001).

CONCLUSIONS

Escherichia coli was the most common pathogen in all nosocomial infection categories. Increased age, gender, and obesity, in addition to catheter-days, were significant risk factors for UTI in trauma patients. Specific risk factors may predispose patients to pathogens that are not ordinarily covered by usually-chosen antibiotic therapy.

Epidemiology of urinary tract infections: incidence, morbidity, and economic costs

Urinary tract infections (UTIs) are considered to be the most common bacterial infection. According to the 1997 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey, UTI accounted for nearly 7 million office visits and 1 million emergency department visits, resulting in 100,000 hospitalizations. Nevertheless, it is difficult to accurately assess the incidence of UTIs, because they are not reportable diseases in the United States. This situation is further complicated by the fact that accurate diagnosis depends on both the presence of symptoms and a positive urine culture, although in most outpatient settings this diagnosis is made without the benefit of culture. Women are significantly more likely to experience UTI than men. Nearly 1 in 3 women will have had at least 1 episode of UTI requiring antimicrobial therapy by the age of 24 years. Almost half of all women will experience 1 UTI during their lifetime. Specific subpopulations at increased risk of UTI include infants, pregnant women, the elderly, patients with spinal cord injuries and/or catheters, patients with diabetes or multiple sclerosis, patients with acquired immunodeficiency disease syndrome/human immunodeficiency virus, and patients with underlying urologic abnormalities. Catheter-associated UTI is the most common nosocomial infection, accounting for >1 million cases in hospitals and nursing homes. The risk of UTI increases with increasing duration of catheterization. In noninstitutionalized elderly populations, UTIs are the second most common form of infection, accounting for nearly 25% of all infections. There are important medical and financial implications associated with UTIs. In the nonobstructed, nonpregnant female adult, acute uncomplicated UTI is believed to be a benign illness with no long-term medical consequences. However, UTI elevates the risk of pyelonephritis, premature delivery, and fetal mortality among pregnant women, and is associated with impaired renal function and end-stage renal disease among pediatric patients. Financially, the estimated annual cost of community-acquired UTI is significant, at approximately $1.6 billion.

Epidemiology of urinary tract infections: incidence, morbidity, and economic costs

Urinary tract infections (UTIs) are considered to be the most common bacterial infection. According to the 1997 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey, UTI accounted for nearly 7 million office visits and 1 million emergency department visits, resulting in 100,000 hospitalizations. Nevertheless, it is difficult to accurately assess the incidence of UTIs, because they are not reportable diseases in the United States. This situation is further complicated by the fact that accurate diagnosis depends on both the presence of symptoms and a positive urine culture, although in most outpatient settings this diagnosis is made without the benefit of culture. Women are significantly more likely to experience UTI than men. Nearly 1 in 3 women will have had at least 1 episode of UTI requiring antimicrobial therapy by the age of 24 years. Almost half of all women will experience 1 UTI during their lifetime. Specific subpopulations at increased risk of UTI include infants, pregnant women, the elderly, patients with spinal cord injuries and/or catheters, patients with diabetes or multiple sclerosis, patients with acquired immunodeficiency disease syndrome/human immunodeficiency virus, and patients with underlying urologic abnormalities. Catheter-associated UTI is the most common nosocomial infection, accounting for >1 million cases in hospitals and nursing homes. The risk of UTI increases with increasing duration of catheterization. In noninstitutionalized elderly populations, UTIs are the second most common form of infection, accounting for nearly 25% of all infections. There are important medical and financial implications associated with UTIs. In the nonobstructed, nonpregnant female adult, acute uncomplicated UTI is believed to be a benign illness with no long-term medical consequences. However, UTI elevates the risk of pyelonephritis, premature delivery, and fetal mortality among pregnant women, and is associated with impaired renal function and end-stage renal disease among pediatric patients. Financially, the estimated annual cost of community-acquired UTI is significant, at approximately $1.6 billion.

Empirical therapy for uncomplicated urinary tract infections in an era of increasing antimicrobial resistance: a decision and cost analysis

Infectious Diseases Society of America guidelines state that uncomplicated urinary tract infections (UTIs) should be treated empirically with trimethoprim-sulfamethoxazole (TMP-SMZ), unless the community resistance among uropathogens exceeds 10%-20%, in which case a fluoroquinolone (FQ) should be used. However, the data to support this threshold are limited. We performed a cost-minimization and sensitivity analysis to determine what level of TMP-SMZ resistance in a community should trigger FQ use. The mean cost of empirical treatment with TMP-SMZ was US$92 when the proportion of resistant Escherichia coli was 0%, $106 when it was 20%, and $120 when it was 40%. The mean cost of empirical FQ treatment was $107 at current levels of FQ resistance. When >22% of E. coli in a community are TMP-SMZ-resistant, empirical FQ therapy becomes less costly than TMP-SMZ therapy. Treatment guidelines for empirical treatment of UTIs may need modification, and the threshold trigger for empirical FQ use should be raised to >20% TMP-SMZ resistance.

Urinary tract infection and pyelonephritis

UTIs are common, potentially severe infections that the emergency physician must manage efficiently and effectively. In most cases, this entity is well recognized, and the clinician will be confident of the correct course. However, in certain populations, complications are common, and the best therapy has yet to be proven. Tailoring the evaluation and treatment to the risk of complications is imperative. With careful evaluation, individualized therapy and close follow-up, the majority of patients can be expected to do well.

Pathogenesis and management of recurrent urinary tract infection in women

A number of pathogenic factors for the development of recurrent urinary tract infection, such as prolonged vaginal colonization with uropathogenic Escherichia coli, nonsecretion of ABH blood-group antigens, impaired local immune response, oestrogen deficiency in postmenopausal women and altered vaginal milieu caused by the use of contraceptives, are involved. Long-term use of antimicrobial agents is the cornerstone of prevention of recurrent urinary tract infection. Other approaches currently used involve self-start (on demand) therapy, oestrogen replacement in postmenopausal women, behavioural changes and alternative therapies, such as acupuncture.