The costs of skull base surgery in the pediatric population.

Objectives To determine the costs of endoscopic endonasal surgery (EES) for pediatric skull base lesions. Methods Retrospective chart review of pediatric patients (ages 1 month to 19 years) treated for skull base lesions with EES from 1999 to 2013. Demographic and operative data were recorded. The cost of care for the surgical day, intensive care unit (ICU), floor, and total overall cost of inpatient stay were acquired from the finance department. Results A total of 160 pediatric patients undergoing EES for skull base lesions were identified. Of these, 55 patients had complete financial data available. The average total inpatient and surgical costs of care were $34, 056 per patient. Angiofibromas were the most costly: $59,051 per patient. Fibro-osseous lesions had the lowest costs: $10,931 per patient. The average ICU stay was 1.8 days at $4,577 per ICU day. The average acute care stay was 3.4 days at $1,961 per day. Overall length of stay was 4.5 days. Three cerebrospinal fluid leaks (4%) and two cases of meningitis (3%) occurred. One tracheostomy was required (1.5%). Conclusions EES is a cost-effective model for removal of skull base lesions in the pediatric population. Costs of care vary according to pathology, staged surgeries, length of ICU stay, and need for second operations.

Targeted prostate cancer screening in men with mutations in BRCA1 and BRCA2 detects aggressive prostate cancer: preliminary analysis of the results of the IMPACT study.

OBJECTIVE: To evaluate the role of targeted prostate cancer screening in men with BRCA1 or BRCA2 mutations, an international study, IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), was established. This is the first multicentre screening study targeted at men with a known genetic predisposition to prostate cancer. A preliminary analysis of the data is reported. PATIENTS AND METHODS: Men aged 40-69 years from families with BRCA1 or BRCA2 mutations were offered annual prostate specific antigen (PSA) testing, and those with PSA > 3 ng/mL, were offered a prostate biopsy. Controls were men age-matched (± 5 years) who were negative for the familial mutation. RESULTS: In total, 300 men were recruited (205 mutation carriers; 89 BRCA1, 116 BRCA2 and 95 controls) over 33 months. At the baseline screen (year 1), 7.0% (21/300) underwent a prostate biopsy. Prostate cancer was diagnosed in ten individuals, a prevalence of 3.3%. The positive predictive value of PSA screening in this cohort was 47·6% (10/21). One prostate cancer was diagnosed at year 2. Of the 11 prostate cancers diagnosed, nine were in mutation carriers, two in controls, and eight were clinically significant. CONCLUSIONS: The present study shows that the positive predictive value of PSA screening in BRCA mutation carriers is high and that screening detects clinically significant prostate cancer. These results support the rationale for continued screening in such men.

Exploring contrary trends in bladder cancer incidence, mortality and survival: implications for research and cancer control.

AIM: To investigate trends in bladder cancer incidence, mortality and survival, and cancer-control implications. METHODS: South Australian Registry data were used to calculate age-standardized incidence and mortality rates from 1980 to 2004. Sociodemographic predictors of invasive as opposed to in situ disease were examined. Determinants of disease-specific survival were investigated using Kaplan-Meier estimates and proportional hazards regression. RESULTS: Incidence rates for invasive cancers decreased by 21% between 1980-84 and 2000-04, similarly affecting men and women. Meanwhile increases occurred for combined in situ and invasive disease. While mortality rates decreased by approximately a third in men and women less than 70 years of age after the early 1990 s, no changes were evident for older residents. The proportion of cancers found at an in situ stage was higher in younger ages and more recent diagnostic periods. Five-year survivals of invasive cases decreased from 64% for 1980-84 diagnoses to 58% for 1995-2004. Multivariable analysis showed that diagnostic period was not predictive of survival after age adjustment (P= 0.719), with lower survival relating to older age, transitional compared with papillary transitional cancers, female sex, indigenous status and a country as opposed to metropolitan residence. CONCLUSIONS: Reductions in invasive disease incidence may be due to increased detection at an in situ stage. The decline in survival from invasive disease in more recent periods is explained by increased age at diagnosis. Poorer outcomes of invasive cases remain for women after adjusting for age, histology, indigenous status and residential location.

Prospective cohort study of microbial and inflammatory events immediately preceding Escherichia coli recurrent urinary tract infection in women.

BACKGROUND: A prospective cohort study was conducted to characterize the temporal sequence of microbial and inflammatory events immediately preceding Escherichia coli recurrent urinary tract infection (rUTI). METHODS: Women with acute cystitis and a history of UTI within the previous year self-collected periurethral and urine samples daily and recorded measurements of urine leukocyte esterase, symptoms, and sexual intercourse daily for 3 months. rUTI strains were characterized by pulsed-field gel electrophoresis and genomic virulence profiling. Urinary cytokine levels were measured. RESULTS: There were 38 E. coli rUTIs in 29 of 104 women. The prevalence of periurethral rUTI strain carriage increased from 46% to 90% during the 14 days immediately preceding rUTI, with similar increases in same-strain bacteriuria (from 7% to 69%), leukocyte esterase (from 31% to 64%), and symptoms (from 3% to 43%), most notably 2-3 days before rUTI (P<.05 for all comparisons). Intercourse with periurethral carriage of the rUTI strain also increased before rUTI (P=.008). Recurrent UTIs preceded by bacteriuria, pyuria, and symptoms were caused by strains less likely to have P fimbriae than other rUTI strains (P=.002). CONCLUSIONS: Among women with frequent rUTIs, the prevalences of periurethral rUTI strain carriage, bacteriuria, pyuria, and intercourse dramatically increase over the days preceding rUTI. A better understanding of the pathogenesis of rUTI will lead to better prevention strategies.

Urinary tract infections in women with type 1 diabetes mellitus: survey of female participants in the epidemiology of diabetes interventions and complications study cohort.

PURPOSE: We determined the prevalence of and risk factors for urinary tract infection in women with type 1 diabetes, and compared the prevalence of cystitis to that in nondiabetic women. MATERIALS AND METHODS: Women enrolled in the Epidemiology of Diabetes Interventions and Complications study were surveyed at year 10 as part of the Uro-EDIC study to assess the prevalence of cystitis and pyelonephritis in the preceding 12 months. Multivariate logistic regression models including measures of glycemic control and vascular complications of type 1 diabetes were used for risk factor analyses. The prevalence of cystitis in Uro-EDIC women was compared to that in a nondiabetic subset of women participants in the National Health and Nutrition Examination Survey III (NHANES III). RESULTS: A total of 550 women participated in the Uro-EDIC survey. The prevalence of cystitis and pyelonephritis in the preceding 12 months was 15% and 3%, respectively. Duration of diabetes, hemoglobin A1C, retinopathy, neuropathy, nephropathy, composite vascular complication score and intensive glycemic therapy during the Diabetes Control and Complications Trial, and Diabetes Control and Complications Trial cohort were not associated with cystitis or pyelonephritis. Sexual activity was associated with increased cystitis risk (adjusted OR 8.28; 95% CI 1.45, 158.32; p = 0.01). The adjusted prevalence of cystitis was 19.1% in Uro-EDIC women and 23.1% in NHANES III participants (adjusted OR 0.78; 95% CI 0.51, 1.22; p = 0.28). CONCLUSIONS: In Uro-EDIC women sexual activity rather than measures of diabetes control and complications was the main risk factor for urinary tract infection. The prevalence of cystitis was similar to that in nondiabetic women participants in NHANES III.

Cranberry products inhibit adherence of p-fimbriated Escherichia coli to primary cultured bladder and vaginal epithelial cells.

PURPOSE: Cranberry proanthocyanidins have been identified as possible inhibitors of Escherichia coli adherence to uroepithelial cells. However, little is known about the dose range of this effect. Furthermore, it has not been studied directly in the urogenital system. To address these issues we tested the effect of a cranberry powder and proanthocyanidin extract on adherence of a P-fimbriated uropathogenic E. coli isolate to 2 new urogenital model systems, namely primary cultured bladder epithelial cells and vaginal epithelial cells. MATERIALS AND METHODS: E. coli IA2 was pre-incubated with a commercially available cranberry powder (9 mg proanthocyanidin per gm) or with increasing concentrations of proanthocyanidin extract. Adherence of E. coli IA2 to primary cultured bladder epithelial cells or vaginal epithelial cells was measured before and after exposure to these products. RESULTS: Cranberry powder decreased mean adherence of E. coli IA2 to vaginal epithelial cells from 18.6 to 1.8 bacteria per cell (p <0.001). Mean adherence of E. coli to primary cultured bladder epithelial cells was decreased by exposure to 50 mug/ml proanthocyanidin extract from 6.9 to 1.6 bacteria per cell (p <0.001). Inhibition of adherence of E. coli by proanthocyanidin extract occurred in linear, dose dependent fashion over a proanthocyanidin concentration range of 75 to 5 mug/ml. CONCLUSIONS: Cranberry products can inhibit E. coli adherence to biologically relevant model systems of primary cultured bladder and vaginal epithelial cells. This effect occurs in a dose dependent relationship. These findings provide further mechanistic evidence and biological plausibility for the role of cranberry products for preventing urinary tract infection.

Outcome of post-prostatectomy radiotherapy in one institution.

We present a retrospective study to evaluate the outcome of postoperative radiotherapy for biochemical or clinical recurrent prostate cancer. Twenty-six patients (median age 60 years) underwent radiotherapy after radical prostatectomy between January 1997 and January 2004. Seven patients received adjuvant radiotherapy and 19 received salvage radiotherapy. The median prostate-specific antigen at diagnosis was 8.6 (0.9-89) and most (23 patients) presented with T(3)N(0) disease. The median follow up was 19.5 months (5-84 months). All patients received a dose of 61.2 Gy at 1.8 Gy per fraction, 20 initially receiving 45 Gy to the lesser pelvis. The median dose to the bladder, rectum and left femoral head were 55.6, 57.5 and 33.8 Gy, respectively. All patients were managed radiotherapeutically by the first author. Twenty-four patients are alive. Two patients have died, one from oesophageal cancer and the second from metastatic prostate cancer. Two other patients also developed metastatic disease. Four asymptomatic patients with a rising prostate-specific antigen are under observation. None of the 26 patients has developed a local recurrence. Seven patients have developed grade 1 late bowel effects and three a grade 2 late effect. Eight patients suffer from grade 1 late genitourinary effects and two from grade 2 effects. One patient developed impotence, whereas 23 patients were rendered impotent postoperatively. There were no grade 3/4 late effects. Postoperative radiotherapy is well tolerated and provides effective local control.

Apolipoprotein-D: a novel cellular marker for HGPIN and prostate cancer.

BACKGROUND: High grade prostatic intraepithelial neoplasia (HGPIN) is a putative pre-malignant lesion of the prostate. While apolipoprotein-D (Apo-D), an androgen-regulated hydrophobic transporter protein, is expressed in prostate tumors, its expression in HGPIN is unknown. METHODS: Immunoreactivity for Apo-D and another androgen-regulated protein, prostate specific antigen (PSA), was investigated in 64 radical prostatectomy tissues by video image analysis. RESULTS: Eighty two percent of prostatectomy specimens demonstrated moderate to strong Apo-D immunoreactivity in areas of HGPIN. In comparison, weak Apo-D immunoreactivity was observed in non-malignant areas in only 24% of specimens. The median (range) percentage cellular area of HGPIN immunopositive for Apo-D (9.7%, 0-42.9), and the cellular concentration of Apo-D (MIOD 3.1, 0-13.3), were intermediate between that of normal (area 0%, 0-53.5%, MIOD 0, 0-12.6) and early stage prostate cancer tissues (area 29.2%, 0-90.8%, MIOD 6.7, 0-28.1). This increase in Apo-D expression from non-malignant, through HGPIN to prostate cancer was statistically significant (P < 0.001), and contrasted with the decrease observed in PSA staining between adjacent areas of normal glands, HGPIN, and cancer (P = 0.026). CONCLUSIONS: The presence of high levels of immunoreactive Apo-D in HGPIN and prostate cancer, but not in non-malignant epithelial cells, is consistent with HGPIN being an intermediate lesion in the transition to prostate cancer, and suggests that cellular Apo-D expression is a marker of malignant transformation of the prostate.

Variation in frequency of the virulence-factor gene in Escherichia coli clones colonizing the stools and urinary tracts of healthy prepubertal girls.

To provide information on virulence expression of Escherichia coli in healthy hosts, stool, periurethral, and urine samples were collected weekly from healthy 3-6-year-old girls who lived in a small rural community. Dominant and nondominant clones were defined in stool specimens, and the expression of virulence factors was determined. We found that healthy girls commonly shared dominant clones. P adhesin, hemolysin, and type I adhesin were commonly found in clones in the stool and in clones in the urinary tract. In addition, expression of virulence factors, among both dominant and nondominant clones in the stool, changed from week to week. The presence of P adhesin was a marker for the persistence of a dominant clone in the stool and was associated with an increased likelihood that a nondominant clone would be detected in the urinary tract. Type I adhesin was ubiquitous among stool strains, with orientation of the fimbrial switch being both in the "off" position and in both the "on" and "off" positions. In summary, the intestinal flora of healthy girls is complex, with frequent changes in virulence expression.

Ultraviolet radiation alters maize phyllosphere bacterial diversity.

Epiphytic bacteria are subjected to very stressful environments, including UV radiation. Bacterial assemblages on Zea mays (maize) leaves exposure were examined with and without UV-B radiation. Culture-independent molecular techniques were utilized for bacterial identification, diversity analysis and selection of putative UV exposure marker sequences. Few sequences corresponded to previously characterized phyllosphere bacteria. There was a strong tendency toward increased 16S rDNA sequence diversity in UV samples. Overall community structure was assessed using denaturing gel gradient electrophoresis; significant alterations in community structure were found in comparisons of phyllosphere bacterial samples from control and solar UV-B exposed plants.

Intraspecific comparisons reveal differences in the pattern of ultraviolet radiation responses in four maize (Zea mays L.) varieties.

Four maize (Zea mays L.) varieties were examined for ultraviolet radiation-induced changes in leaf rolling, biomass, fluctuating leaf asymmetry and DNA damage. Short-term dose-response curves for each response were constructed and responses in each line compared. The four varieties each exhibited a different pattern of tolerance and reactivity, ranging from B73, which was tolerant in all four measures, to TS1, which was affected in DNA damage levels and leaf rolling but unaffected in biomass accumulation and fluctuating leaf asymmetry. The pattern of ultraviolet radiation responses allows us to narrow the possibilities for the source of the defect in reactive varieties. The four varieties tested include inbred parents that have been used to construct recombinant inbred lines and a variety that is found in the background of the engineered RescueMu transposon mutagenesis lines. These dose-response curves and variety comparisons provide the foundation for genetic dissection of the mechanisms of ultraviolet radiation responses in maize.

Simple, sensitive and accurate method for the quantification of prothrombin mRNA by using competitive PCR.

A method for the quantification of prothrombin (PT) mRNA species in hepatic tissues of rats was developed with the use of competitive PCR. To validate the quantification approach, sequential dilutions of total RNA from one of the samples were reverse transcribed. Their equivalent volumes were amplified together with a known amount of non-homologous competitor cDNA with identical nucleotide primers. The disparate sizes of target and competitor permitted the easy identification and quantification of bands in samples after densitometric analysis of ethidium bromide-stained agarose gels. Ratios of intensities of target and competitor bands were plotted against the initial amounts of total RNA species used, giving a linear relationship. The slope of this line was virtually identical with that obtained when the sample RNA was replaced with recombinant target cDNA, indicating that recombinant cDNA behaved in PCR identically with that made by reverse transcription and permitting the estimation of transcripts in reverse transcription reactions by using the recombinant counterpart of each as a standard. To avoid variation in the final results, the amount of competitor used in the assay was calculated separately from the equivalence point of the reverse-transcribed total RNA of one of the tissue samples; PCR was performed only for the minimum number of cycles required to detect products. A standard curve was made in each PCR run by amplifying differing amounts of recombinant cDNA species of PT or beta-actin together with a constant amount of its competitor. The numbers of transcripts in the tissues were then determined directly by PCR incorporating the same amount of respective competitor (as used in the standard curve) and comparing the ratios of products with the standard curve. Application of this method revealed that the median ratio of PT message to beta-actin message in hepatic tissues of 10 normal rats was 0.37, with a mean+/-S.D. of 0.37+/-0.07 (range 0.27-0.47). Although the method was developed for the quantification of PT transcripts in liver, it can easily be used for non-hepatic tissues as well. The technique is simple, quick and sensitive and requires only a very small amount of substrate.

Attitudes to evidence-based practice in urology: results of a survey.

BACKGROUND: The advantages of promoting evidence-based care through implementation of clinical guidelines are well established. Clinical practice guidelines have been developed for lower urinary tract symptoms (LUTS) and prostate cancer screening. Aspects of the delivery of care by urologists or specialist registrars relevant to the guidelines were assessed. METHODS: A questionnaire was distributed at the 1999 meeting of the Urological Society of Australasia, which was attended by 187 Australasian and 33 foreign delegates. Questions addressed access to resources for evidence-based medicine; perceived need; preferred sources of information; and then presented four clinical scenarios. These were: (i) treatment recommendations in early stage prostate cancer; (ii) the same scenario if the respondent was the patient; (iii) treatment recommendations after radical prostatectomy when there was a positive resection margin; and (iv) clinical investigations for mild to moderate LUTS. RESULTS: Of 220 possible responses, 132 were received, a response rate of 60%. Urologists overwhelmingly (100%) endorsed the need for access to evidence-based reviews, although 28% claimed such access was non-existent to poor. Clinical guidelines were the preferred source of evidence-based information. For early stage prostate cancer in a 55-year-old man, radical prostatectomy was recommended by 93.2% of respondents, but this dropped to 83% when the respondent was the patient (P < 0.05), and a wider range of treatments was recommended. Pelvic radiotherapy and hormone therapy were equally recommended for biochemical progression following radical prostatectomy where there was a positive surgical margin. Investigations for LUTS included serum prostate-specific antigen (PSA) testing (78.0%) and voided flow studies (77.3%). CONCLUSIONS: Urologists express a need for evidence-based practice resources, in particular clinical guidelines. Nevertheless their clinical approach is not necessarily consistent with existing guidelines, particularly for LUTS. An alteration in the recommendation when the respondent is the patient of interest and endorses the recommendation that patients with prostate cancer should be involved in treatment decisions.

Clonal relationships and extended virulence genotypes among Escherichia coli isolates from women with a first or recurrent episode of cystitis.

To identify bacterial predictors of recurrence and/or persistence in acute cystitis, extended virulence genotypes were compared with clonal background and epidemiologic status among 74 Escherichia coli urine isolates from women with first or recurrent episodes of urinary tract infection (UTI). Sequential isolates from patients with recurrent UTI were classified, using macrorestriction analysis, as having caused an isolated recurrence versus a single or multiple same-strain recurrences. papA, papG allele II, iha, and iutA predicted multiple same-strain recurrences, whereas nfaE and the absence of sfaS or fyuA predicted isolated recurrences. Phylogenetic group B2 accounted for 70% of isolates and for most of the putative virulence factors (VFs) studied. The meningitis-associated O18:K1:H7 clonal group comprised 18% of isolates, exhibited multiple VFs, and caused "once-only" recurrences less commonly than did other strains. These findings identify specific VFs and clonal groups against which preventive interventions might be beneficial and illustrate the importance of delineating pathogenetically relevant subgroups within the "recurrent cystitis" population.

CD40 is not detected on human prostate cancer cells by immunohistologic techniques.

OBJECTIVES: The CD40 antigen is expressed by antigen-presenting cells, many kinds of epithelium, and carcinomas. As signaling through CD40 modulates the differentiation state of CD40-expressing cells, we wanted to investigate whether benign or malignant prostate epithelium expressed CD40. METHODS: Twenty-two paraffin-embedded and 10 snap-frozen human prostate tissue samples were analyzed by immunohistologic methods, using the basal cell-specific markers, high molecular weight cytokeratin (HMWCK) and keratin-14 (K14), and the luminal cell marker, low molecular weight cytokeratin (LMWCK), together with CD40. Fresh prostate tissue was cultured in vitro and analyzed by immunocytofluorescence. RESULTS: The pattern of CD40 expression was continuous on basal epithelial cells of normal and hyperplastic prostate glands but discontinuous in glands that featured prostatic intraepithelial neoplasia. Coexpression of CD40 with the basal cell-specific cytokeratins, HMWCK and K14, was confirmed by double labeling. In contrast, glandular epithelial cells in prostate adenocarcinoma did not express CD40 or these cytokeratins. A luminal cell phenotype defined as CAM5.2-positive and HMWCK-negative K14-negative was identified among primary epithelial cells cultured in vitro. Most of the cultured cells (more than 99%) were also CD40-negative. CONCLUSIONS: Together, our results support the hypothesis that CD40 expression correlates with the basal cell phenotype, which is lost upon malignant transformation of the prostate. Hence, CD40 may be useful diagnostically to distinguish benign from malignant prostate lesions in biopsy material.

Effects of vaginal intercourse with and without a condom on vaginal flora and vaginal epithelium.

Effects of a single episode of intercourse on vaginal flora and epithelium were examined in subjects randomly assigned to groups that used no condom or lubricated nonspermicide condoms. Subjects were evaluated at visits before (1 month and 1-2 days) and after (8-12 h, 2-3 days, and 6-8 days) an index episode of sexual intercourse. The 22 subjects who used no condoms had significantly more Escherichia coli and a high concentration (> or =10(5) cfu/mL) of E. coli in the vagina (both, P<.001) and urine (all <10(5) cfu/mL; P=.004) at visit 3 than at visits 1 and 2. The 20 subjects who used condoms had a trend toward more vaginal E. coli (P=.06) and a significant increase in other enteric gram-negative rods (P=.001) after intercourse. Intercourse was not associated with gross, colposcopic, or histologic vaginal epithelial abnormalities.

Effects of oral contraceptive pill use on vaginal flora and vaginal epithelium.

The objective of this study was to examine the effect of oral contraceptive (OC) use on vaginal discharge, epithelium, and flora. Thirty women who planned to use OC for contraception were evaluated before and 2 months after the start of OC use. At both visits, genital symptoms and exposures were assessed by questionnaire; vaginal signs were assessed by speculum examination and colposcopy; vaginal microflora was evaluated by quantitative culture; and a vaginal biopsy was obtained for histopathologic evaluation. Variables were compared between the initial visit and after 2 months of OC use. It was found that OC use did not change the gross, colposcopic, or histologic appearance of the vaginal epithelium or characteristics of vaginal or cervical discharge. Vaginal flora essentially remained unchanged after 2 months of OC use, except that a small decrease occurred in the number of subjects with > or =10(5) colony forming units/mL of H(2)O(2) producing Lactobacillus from 16 at baseline to 9 (p = 0.04) and in the total number of subjects with Ureaplasma urealyticum from 17 at baseline to 10 of 29 (p = 0.04). The results indicate minimal effect of OC use on the vaginal epithelium and vaginal and cervical discharge, and a small effect on vaginal flora.

Factors predicting recovery of erections after radical prostatectomy.

PURPOSE: Because preservation of functioning penile erections is a major concern for many patients considering treatment for localized prostate cancer, we analyzed various factors determined before and after radical retropubic prostatectomy to identify those significantly associated with recovery of erectile function. MATERIALS AND METHODS: Our prospective database of patients undergoing pelvic lymphadenectomy and radical retropubic prostatectomy was used to determine factors predictive of erection recovery after radical prostatectomy. The study included 314 consecutive men with prostate cancer treated with radical retropubic prostatectomy between November 1993 and December 1996. Preoperative potency satisfactory for intercourse and degree of neurovascular bundle preservation during the operation were documented. RESULTS: Patient age, preoperative potency status and extent of neurovascular bundle preservation but not pathological stage were predictive of potency recovery after radical prostatectomy. At 3 years after the operation 76% of men younger than age 60 years with full erections preoperatively who had bilateral neurovascular bundle preservation would be expected to regain erections sufficient for intercourse. Compared to the younger men, those 60 to 65 years old were only 56% (95% confidence interval [CI] 37 to 84) and those older than 65 years were 47% (95% CI 30 to 73) as likely to recover potency. Patients with recently diminished erections were only 63% (95% CI 38 to 100) as likely to recover potency as men with full erections preoperatively, and those with partial erections were only 47% (95% CI 23 to 96) as likely to recover potency. Resection of 1 neurovascular bundle reduced the chance of recovery to 25% (95% CI 10 to 61) compared to preserving both nerves. CONCLUSIONS: Knowledge of preoperative erectile function and patient age before the operation and the degree of neurovascular bundle preservation afterward may aid in patient counseling regarding potency recovery after radical prostatectomy.

A prospective study of asymptomatic bacteriuria in sexually active young women.

BACKGROUND: Asymptomatic bacteriuria is common in young women, but little is known about its pathogenesis, natural history, risk factors, and temporal association with symptomatic urinary tract infection. METHODS: We prospectively evaluated 796 sexually active, nonpregnant women from 18 through 40 years of age over a period of six months for the occurrence of asymptomatic bacteriuria (defined as at least 10(5) colony-forming units of urinary tract pathogens per milliliter). The women were patients at either a university student health center or a health maintenance organization. Periodic urine cultures were taken, daily diaries were kept, and regularly scheduled interviews were performed. Escherichia coli strains were tested for hemolysin, the papG genotype, and the ribosomal RNA type. RESULTS: The prevalence of asymptomatic bacteriuria (the proportion of urine cultures with bacteriuria in asymptomatic women) was 5 percent (95 percent confidence interval, 4 percent to 6 percent) among women in the university group and 6 percent (95 percent confidence interval, 5 percent to 8 percent) among women in the health-maintenance-organization group. Persistent asymptomatic bacteriuria with the same E. coli strain was rare. Symptomatic urinary tract infection developed within one week after 8 percent of occasions on which a culture showed asymptomatic bacteriuria, as compared with 1 percent of occasions when asymptomatic bacteriuria was not found (P<0.001). Asymptomatic bacteriuria was associated with the same risk factors as for symptomatic urinary tract infection, particularly the use of a diaphragm plus spermicide and sexual intercourse. CONCLUSIONS: Asymptomatic bacteriuria in young women is common but rarely persists. It is a strong predictor of subsequent symptomatic urinary tract infection.