Consumption of sweetened, dried cranberries may reduce urinary tract infection incidence in susceptible women--a modified observational study.

BACKGROUND: Urinary tract infections (UTIs) are one of the most common bacterial infections, and over 50% of women will have a UTI during their lifetimes. Antibiotics are used for prophylaxis of recurrent UTIs but can lead to emergence of drug-resistant bacteria. Therefore, it is reasonable to investigate nutritional strategies for prevention of UTIs. Cranberry juices and supplements have been used for UTI prophylaxis, but with variable efficacy. Because dried cranberries may contain a different spectrum of polyphenolics than juice, consuming berries may or may not be more beneficial than juice in decreasing the incidence of UTIs in susceptible women. The primary objectives of this study were to determine if consumption of sweetened, dried cranberries (SDC) decreases recurrent UTIs and whether this intervention would alter the heterogeneity, virulence factor (VF) profiles, or numbers of intestinal E. coli. METHODS: Twenty women with recurrent UTIs were enrolled in the trial and consumed one serving of SDC daily for two weeks. Clinical efficacy was determined by two criteria, a decrease in the six-month UTI rates pre- and post-consumption and increased time until the first UTI since beginning the study. Strain heterogeneity and virulence factor profiles of intestinal E. coli isolated from rectal swabs were determined by DNA fingerprinting and muliplex PCR, respectively. The numbers of intestinal E. coli eluted from rectal swabs pre- and post-consumption were also quantified. RESULTS: Over one-half of the patients did not experience a UTI within six months of SDC consumption, and the mean UTI rate per six months decreased significantly. Kaplan-Meier analysis of infection incidence in women consuming SDC compared to patients in a previous control group showed a significant reduction in time until first UTI within six months. The heterogeneity, VF profiles, and prevalence of intestinal E. coli strains were not significantly different after cranberry consumption. CONCLUSIONS: Results of this study indicate a beneficial effect from consuming SDC to reduce the number of UTIs in susceptible women. Because there were no changes in the heterogeneity or VF profiles of E. coli, additional studies are needed to determine the mechanism of action of SDC for reduction of UTIs.

Lack of association between the Tlr4 (Lpsd/Lpsd) genotype and increased susceptibility to Escherichia coli bladder infections in female C3H/HeJ mice.

UNLABELLED: Toll-like receptor 4 is thought to have a primary role in host defense against Escherichia coli bladder colonization, based on mouse models of urinary tract infection using C3H/HeJ female mice. This strain carries a point mutation in the Tlr4 gene, which renders the mice unresponsive to lipopolysaccharide (LPS) and thus limits the bladder inflammatory response and infection resolution. The importance of Tlr4 as the sole genetic determinant of resistance or susceptibility can be questioned, however, by the observation that C3H/HeOuJ female mice with a functional Tlr4 do not effectively resolve E. coli bladder infections. The present study further examined this inconsistency by investigating the association of Tlr4 Lps(d) and Lps(n) alleles with bladder infection susceptibility by using genetic crosses of C3H/HeJ mice with Tlr4 (Lps(n)/Lps(n)) or (Lps(n)/Lps(d)) mice. Heterozygous offspring of C3H/HeJ (Lps(d)/Lps(d)) × BALB/cAnN (Lps(n)/Lps(n)) mice successfully resolved bladder infections induced by a uropathogenic E. coli strain, while heterozygous mice from a C3H/HeJ (Lps(d)/Lps(d)) × C3H/HeOuJ (Lps(n)/Lps(n)) cross had severe infections. A backcross of C3H/HeJ (Lps(d)/Lps(d)) with (BALB/cAnN × C3H/HeJ)F(1) (Lps(n)/Lps(d)) produced mice that were either resistant or susceptible to E. coli bladder infections and had Lps(d)/Lps(d) or Lps(n)/Lps(d) Tlr4 genotypes. The Lps(d)/Lps(d) or Lps(n)/Lps(d) genotypes were present in individual mice with unresolved bladder infections, and the Lps(d)/Lps(d) genotype was found in infection-resistant mice. These results indicate that at least one gene other than Tlr4 strongly influences susceptibility to E. coli bladder infections in C3H/HeJ mice. IMPORTANCE: We have previously demonstrated that mouse strains with either a functional or nonfunctional Tlr4 were not able to resolve induced Escherichia coli bladder infections and that a chromosomal site distinct from Tlr4 was associated with an inability to resolve bladder infections in C3H/HeJ mice. The present study has further investigated the relevance of Tlr4 in bladder infection resolution by defining the Tlr4 alleles present in offspring of genetic crosses of C3H/HeJ mice with infection-resistant and -susceptible inbred strains. The results of these experiments showed that mice with a normal Tlr4 on different genetic backgrounds were not able to clear E. coli bladder infections and that animals with a defective Tlr4 could successfully resolve infections. These results strongly imply the presence of a gene other than in Tlr4 as an important genetic determinant of infection resistance/susceptibility in C3H/HeJ and other inbred mouse strains used in mouse models of infectious diseases.

Quantitative trait loci associated with susceptibility to bladder and kidney infections induced by Escherichia coli in female C3H/HeJ mice.

BACKGROUND: The C3H/HeJ mouse strain develops severe bladder and kidney infections after receiving intravesical inoculation with uropathogenic Escherichia coli. This susceptibility is genetically determined, but the specific genes involved have not been completely defined. The objective of the present study was to use quantitative trait locus (QTL) mapping to identify chromosomal sites associated with susceptibility to infection in C3H/HeJ mice. METHODS: Female mice from a backcross of C3H/HeJ and (BALB/cxC3H/HeJ)F1 mice were inoculated with E. coli, and the number of E. coli colony-forming units present in the bladder and kidneys was quantified 10 days later. Genomic DNA was scanned using microsatellite markers to localize chromosomal segments derived from parental strains. Statistical analyses associated infection phenotypes with chromosomal sites. RESULTS: A highly significant QTL for susceptibility to bladder infection was identified on chromosome 4, and C3H/HeJ alleles at this locus interacted with BALB/c alleles on chromosome 19 to increase the severity of infection. A significant QTL on chromosome 6 was associated with severe kidney infections. CONCLUSIONS: Increased susceptibility to E. coli bladder and kidney infections in female C3H/HeJ mice is associated with specific chromosomal sites located near genes contributing to host resistance to infection. The results demonstrate the multigenic nature of susceptibility to urinary tract infections.

Acute acrolein-induced cystitis in mice.

OBJECTIVE: To develop a method of direct intravesical administration of acrolein and evaluate the severity of cystitis in response to increasing doses of acrolein in female C57BL/6N (C57) mice, with further studies to compare the severity of acute acrolein-induced cystitis among C57, C3H/HeJ (HeJ), and C3H/OuJ (OuJ) strains of mice, as chemical cystitis produced by the systemic administration of cyclophosphamide is thought to result from renal excretion of hepatic metabolites, particularly acrolein. MATERIALS AND METHODS: Doses of acrolein (0-1000 microg, 15 microL total volume) were instilled into the bladders of C57 female mice; the bladders were removed 4 or 24 h later, weighed, and processed for histology. Acrolein (6 or 10 microg; 15 microL) was instilled into the bladders of C57, HeJ and OuJ female mice, the bladders removed 4 or 24 h later, weighed, and processed for standard histology and immunohistochemical detection of uroplakin. RESULTS: Increasing doses of acrolein up to 100-200 microg caused a linear increase in bladder weight and greater histological evidence of inflammation. Doses of >200 microg caused submaximal increases in bladder weight, apparently due to structural damage of the bladder. Bladder weight and submucosal oedema were consistently greater in C57 and HeJ than OuJ mice. Treatment with acrolein caused loss of urothelium along with uroplakin in some areas of all bladder sections 4 h after treatment. Bladders from C57 mice had some loss of urothelium 24 h after instillation of 6 or 10 microg acrolein, but urothelium and uroplakin covered nearly all the surface of bladders of HeJ and OuJ mice 24 h after treatment. There were significantly more white blood cells in bladders from C57 or HeJ mice than in bladders from OuJ mice 24 h after an instillation of 6 or 10 microg acrolein. CONCLUSIONS: Intravesical instillation of acrolein produces dose-dependent cystitis in mice. OuJ mice appear relatively more resistant to irritant effects of intravesical acrolein than C57 or HeJ mice, and future studies will be directed at identifying genetic causes for these differences.

Vaginal mucosal vaccine for recurrent urinary tract infections in women: results of a phase 2 clinical trial.

PURPOSE: We assessed the clinical efficacy of vaginal mucosal immunization with a multivalent bacterial vaccine in women with recurrent urinary tract infections. MATERIALS AND METHODS: A total of 75 patients in a double-blind study were randomly assigned to receive placebo only, primary immunization without boosters, or primary immunization plus boosters using vaginal suppositories containing placebo or vaccine. Vaccine suppositories contained 10 strains of heat-killed uropathogenic bacteria and placebo suppositories had no vaccine organisms. All women were monitored for 6 months to record the number of infections and adverse events. RESULTS: Analysis of data on urinary tract infections caused by any bacteria showed the greatest difference in infection rates between patients in the vaccine plus boosters protocol compared to those receiving placebo only (p = 0.100). When only E. coli urinary tract infections were considered in the analysis, urinary tract infection recurrence rates were significantly less in women given booster immunizations compared to placebo (p = 0.0015). Furthermore, women who received vaccine with boosters and who were sexually active, less than 52 years old, or had not undergone hysterectomy had E. coli urinary tract infections at a much lower rate than women given placebo only (p = 0.0002, 0.002 and 0.003, respectively). No significant adverse events were associated with vaccine treatment. CONCLUSIONS: This study demonstrated the efficacy of vaginal mucosal immunization with a multivalent vaccine in reducing recurrence of E. coli urinary tract infections. The results suggest that the vaccine may provide the most benefit to sexually active women in the 20 to 50-year-old age group.

Chronic bacterial infection and inflammation incite reactive hyperplasia in a mouse model of chronic prostatitis.

BACKGROUND: Chronic inflammation is postulated to contribute to prostate carcinogenesis. We developed a mouse model of chronic prostatitis to test whether infection-induced chronic inflammation would incite reactive changes in prostatic epithelium. METHODS: Prostate tissues harvested from either phosphate-buffered saline (PBS) or E. coli-infected mice were evaluated for histological changes and immunostained for markers of oxidative stress and epithelial cell proliferation. RESULTS: As compared to PBS-treated controls, mice infected with E. coli bacteria for 5 days showed foci of uniformly acute inflammation in the glandular lumen and a persistent inflammation at 12 weeks post-inoculation in the stroma. Prostatic glands showing varying degrees of atypical hyperplasia and dysplasia had stronger staining for oxidative DNA damage and increased epithelial cell proliferation than normal prostatic glands. CONCLUSIONS: These data demonstrate that chronic inflammation induces reactive hyperplasia associated with oxidative stress injury and support the proposed linkage among inflammation, oxidative DNA damage, and prostate carcinogenesis.

Mouse model for acute bacterial prostatitis in genetically distinct inbred strains.

OBJECTIVES: Prostatitis is a common urologic disease seen in adult men. As many as 50% of men will experience an episode of prostatitis in their lifetime, and 2% to 3% of men will have bacterial prostatitis. Because the pathogenic mechanisms of prostatitis remain unclear, we developed a reproducible mouse model of bacterial prostatitis in which to study the etiology and host factors associated with infection susceptibility. METHODS: Male BALB/c, C3H/HeJ, C3H/HeOuJ, C57BL/6J, and (BALB/c x C3H/HeJ)F1 mice 13 weeks old were inoculated intraurethrally with 2 x 10(6) or 2 x 10(8) Escherichia coli. Control mice were inoculated with phosphate-buffered saline. The animals were killed at 5 days after inoculation to assess the intensities of the bladder and prostate infections. RESULTS: Significant bladder or prostate infections were not present in the BALB/c, C57BL/6J, or (BALB/c x C3H/HeJ)F1 mice at either inoculum dose. In contrast, both C3H/HeJ and C3H/HeOuJ mice developed high bladder infections and severe, acute prostatitis at both doses. Control mice infected with phosphate-buffered saline had no bladder or prostate infections. The P values were less than 0.01 for the comparison of bladder and prostate colony-forming units between C3H/HeJ or C3H/HeOuJ and BALB/c, C57BL/6J, or F1 mice. CONCLUSIONS: The strain-dependent differences in susceptibility indicate that genetic factors may play a major role in the etiology of bacterial prostatitis. Because F1 mice did not develop significant bladder and prostate infections, similar to the BALB/c parents, it appears that infection susceptibility is a recessive trait. The availability of this model will allow us to investigate the immunology, genetics, and histopathologic features of bacterial infection of the prostate.

Phase 2 clinical trial of a vaginal mucosal vaccine for urinary tract infections.

PURPOSE: Recurrent urinary tract infections (UTIs) in susceptible women remain a common urological condition. With an increasing number of UTIs being caused by antibiotic resistant bacteria there is a need for alternatives to antibiotics. We determined whether multiple doses of a vaginal mucosal vaccine are effective for increasing long-term resistance to recurrent UTIs. MATERIALS AND METHODS: A total of 54 women were entered into a double-blind, placebo controlled, phase 2 clinical trial using a vaginal vaccine containing 10 heat killed uropathogenic bacteria. Patients were withdrawn from prophylactic antibiotics and randomly assigned to 1 of 3 treatment groups, namely placebo only, primary immunization or primary plus booster immunizations. Subjects received treatments at 0, 1, 2, 6, 10 and 14 weeks. Placebo treated patients received suppositories without bacteria. The primary immunization group received vaccine suppositories, followed by 3 doses of placebo. Patients receiving booster immunizations were given 6 vaccine suppositories. All women were followed for 6 months to determine the time until first recurrence, number of infections and adverse reactions. RESULTS: Women receiving 6 vaccine doses remained free of infections for a significantly longer period than those receiving placebo or primary immunizations. Of patients receiving 6 immunizations 55% did not experience an infection, whereas 89% of placebo treated women had UTIs. No women had significant adverse effects. CONCLUSIONS: This study demonstrates that vaginal mucosal vaccine given for a 14-week period increased the time to re-infection in UTI susceptible women. The infrequent, minimal adverse reactions confirm previous observations on the safety of this vaginal mucosal immunization regimen.

Inheritance of susceptibility to induced Escherichia coli bladder and kidney infections in female C3H/HeJ mice.

In the present study, the inheritance of resistance and susceptibility to bladder and kidney infections in BALB/c, C3H/HeJ, F(1), and backcross mice was investigated, and the number of genes contributing to the phenotypes was estimated. Infections were induced in female mice by intravesical inoculation with Escherichia coli, and the number of bacteria in bladder and kidneys was quantified at 10 days. The (BALB/c x C3H/HeJ) F(1) mice had bladder and kidney infection intensities equivalent to those observed in the resistant BALB/c parents. Twelve percent of the (F(1) x C3H/HeJ) backcross mice had severe bladder infections, similar to the susceptible C3H/HeJ parents. Kidney infections ranging in intensity between those observed in BALB/c and C3H/HeJ parents were present in one-half of the backcross mice. Statistical analyses indicated that >/=1 gene is responsible for the increased susceptibility of C3H/HeJ mice and that the trait appears to be recessive.

Vaccine Development for the Prevention of Urinary Tract Infections.

The effectiveness of antibiotic prophylaxis for recurrent urinary tract infections is being compromised as increasing numbers of uropathogens develop resistance to conventional antibiotics. Because one alternative to antibiotic therapy is immunization of susceptible patients to increase innate resistance, several different vaccines are currently being developed. Four of the vaccines contain a mixture of whole bacteria or an antigenic extract and are administered as a vaginal suppository or oral tablet. A parenteral route is being used in clinical trials of the Escherichia coli type 1 fimbrial adhesin and its chaperone protein. The safety of both the mucosal and parenteral vaccines has been demonstrated in phase 1 clinical trials. Phase 2 trials have shown the efficacy of a vaginal mucosal vaccine containing whole bacteria and an oral vaccine prepared from bacterial lysates. Further clinical trials will allow comparisons of the various vaccines and evaluation of their effectiveness relative to prophylactic antibiotic therapy.

Identification of virulence genes in uropathogenic Escherichia coli by multiplex polymerase chain reaction and their association with infectivity in mice.

OBJECTIVES: To use multiplex polymerase chain reaction (PCR) to screen a large number of Escherichia coli clinical isolates for virulence factor genes and to evaluate the importance of several known factors in the etiology of urinary tract infection. METHODS: Eighty-six E. coli isolates from urine or vaginal or rectal swabs of patients with recurrent urinary tract infection were screened for P fimbria (pap), hemolysin (hly), aerobactin (aer), cytotoxic necrotizing factor 1 (cnf1), S fimbria (sfa), and afimbrial adhesion I (afaI) genes by multiplex PCR. The phenotype of the strains was determined for type 1 fimbriae and O antigen serotype. The infectivity of 11 strains with different combinations of virulence factors was tested using a mouse model of unobstructed urinary tract infection. RESULTS: Type 1 fimbriae were present in 81 of the 86 strains and was the only virulence factor in approximately one third of the isolates. Genes for hly, aer, cnf1, sfa, or pap were present in approximately one fourth of the strains; afaI was present less frequently. A positive type 1 fimbriae phenotype was common to all strains that induced a bladder infection in mice. CONCLUSIONS: Multiplex PCR methods can be effectively applied to studies that require genetic screening of numerous E. coli uropathogens. Where phenotypic information was available, it was consistent with genotypes identified by PCR. Infectivity studies showed that the presence of the type 1 fimbriae gene in an E. coli isolate was required to establish a bladder infection. Other genes that were not identified in this study may also be required in mice and humans.