Vaginal immunization of monkeys against urinary tract infection with a multi-strain vaccine

A cynomolgus monkey E. coli urinary tract infection model confirms efficacy of new FimH vaccine candidates

The increase in urinary tract infections (UTI) caused by antibiotic-resistant Escherichia coli requires the development of new therapeutic agents and prophylactic vaccines. To evaluate the efficacy of new lead candidates, we implemented a cynomolgus macaque UTI challenge model that mimics human uncomplicated cystitis in response to transurethral challenge with a multidrug-resistant (MDR) E. coli serotype O25b ST131 isolate. E. coli fimbrial adhesin FimH and O-antigens are separately under clinical evaluation by others as vaccine candidates to prevent UTI and invasive urosepsis disease, respectively. Accordingly, we assessed the protective efficacy of three 50-µg intramuscular doses of a novel recombinant FimH antigen adjuvanted with liposomal QS21/MPLA compared with saline placebo in groups of nine animals. A third group was vaccinated with this FimH formulation in combination with 1 µg each of a four-valent mixture of serotype O1a, O2, O6, and O25b O-antigen CRM197 lattice glycoconjugates. Both vaccines elicited high levels of serum FimH IgG and adhesin blocking antibodies at the time of bacterial challenge and, for the combination group, O-antigen-specific antibodies. Following bacterial challenge, both vaccinated groups showed >200- and >700-fold reduction in bacteriuria at day 2 and day 7 post-infection compared with placebo, respectively. In parallel, both vaccines significantly reduced levels of inflammatory biomarkers IL-8 and myeloperoxidase in the urine at day 2 post-infection relative to placebo. Results provide preclinical proof-of-concept for the prevention of an MDR UTI infection by these new vaccine formulations.

From mucosal infection to successful cancer immunotherapy

The clinical management of advanced malignancies of the upper and lower urinary tract has been revolutionized with the advent of immune checkpoint blockers (ICBs). ICBs reinstate or bolster pre-existing immune responses while creating new T cell specificities. Immunogenic cancers, which tend to benefit more from immunotherapy than cold tumours, harbour tumour-specific neoantigens, often associated with a high tumour mutational burden, as well as CD8+ T cell infiltrates and ectopic lymphoid structures. The identification of beneficial non-self tumour antigens and natural adjuvants is the focus of current investigation. Moreover, growing evidence suggests that urinary or intestinal commensals, BCG and uropathogenic Escherichia coli influence long-term responses in patients with kidney or bladder cancer treated with ICBs. Bacteria infecting urothelium could be a prominent target for T follicular helper cells and B cells, linking innate and cognate CD8+ memory responses. In the urinary tract, commensal flora differ between healthy and tumoural mucosae. Although antibiotics can affect the prognosis of urinary tract malignancies, bacteria can have a major influence on cancer immunosurveillance. Beyond their role as biomarkers, immune responses against uropathogenic commensals could be harnessed for the design of future immunoadjuvants that can be advantageously combined with ICBs.

Local induction of bladder Th1 responses to combat urinary tract infections

Given the high frequency of urinary tract infections (UTIs) and their recurrence, there is keen interest in developing effective UTI vaccines. Currently, most vaccine studies, including those in humans, involve parenteral vaccination aimed at evoking and sustaining elevated levels of systemic antibody directed at the uropathogens. In view of recent reports of aberrant Th2-biased bladder immune responses to infection, we hypothesized that immunizing mice intravesically with antigens from uropathogenic Escherichia coli (UPEC) combined with a Th1-skewing adjuvant could correct this defect and promote protection against UTIs. Here we report that compared with mice immunized subcutaneously with this vaccine combination, intravesically immunized mice were markedly more protected from UTIs because of their distinctive ability to recruit Th1 cells into the bladder. This mode of vaccination was effective even in mice that experienced multiple UTIs and displayed pronounced aberrant bladder immune responses. Thus, intravesical vaccination with one or more UPEC antigens to induce bladder Th1 responses represents a superior strategy to combat UTIs, especially in UTI-prone subjects.

Needle-Free Immunization with Chitosan-Based Systems

Despite successful use, needle-based immunizations have several issues such as the risk of injuries and infections from the reuse of needles and syringes and the low patient compliance due to pain and fear of needles during immunization. In contrast, needle-free immunizations have several advantages including ease of administration, high level of patient compliance and the possibility of mass vaccination. Thus, there is an increasing interest on developing effective needle-free immunizations via cutaneous and mucosal approaches. Here, we discuss several methods of needle-free immunizations and provide insights into promising use of chitosan systems for successful immunization.

Drug and Vaccine Development for the Treatment and Prevention of Urinary Tract Infections

Urinary tract infections (UTI) are among the most common bacterial infections in humans, affecting millions of people every year. UTI cause significant morbidity in women throughout their lifespan, in infant boys, in older men, in individuals with underlying urinary tract abnormalities, and in those that require long-term urethral catheterization, such as patients with spinal cord injuries or incapacitated individuals living in nursing homes. Serious sequelae include frequent recurrences, pyelonephritis with sepsis, renal damage in young children, pre-term birth, and complications of frequent antimicrobial use including high-level antibiotic resistance and Clostridium difficile colitis. Uropathogenic E. coli (UPEC) cause the vast majority of UTI, but less common pathogens such as Enterococcus faecalis and other enterococci frequently take advantage of an abnormal or catheterized urinary tract to cause opportunistic infections. While antibiotic therapy has historically been very successful in controlling UTI, the high rate of recurrence remains a major problem, and many individuals suffer from chronically recurring UTI, requiring long-term prophylactic antibiotic regimens to prevent recurrent UTI. Furthermore, the global emergence of multi-drug resistant UPEC in the past ten years spotlights the need for alternative therapeutic and preventative strategies to combat UTI, including anti-infective drug therapies and vaccines. In this chapter, we review recent advances in the field of UTI pathogenesis, with an emphasis on the identification of promising drug and vaccine targets. We then discuss the development of new UTI drugs and vaccines, highlighting the challenges these approaches face and the need for a greater understanding of urinary tract mucosal immunity.

Extraintestinal isolates ofEscherichia coli: identification and prospects for vaccine development

Extraintestinal pathogenic Escherichia coli (ExPEC) cause a wide variety of infections that are responsible for significant morbidity, mortality and costs to our healthcare system. Thereby, the development of an efficacious ExPEC vaccine will minimize disease and may be cost-effective in selected patient groups. Surface polysaccharides, such as capsule, have been traditional targets for vaccine development. Considering that significant antigenic heterogeneity exists among surface polysaccharides present in various ExPEC strains, their use as vaccine candidates will be challenging. Therefore, alternative vaccine candidates/approaches are being identified and evaluated and are discussed in this review. The authors envision that an efficacious ExPEC vaccine will consist of either a polyvalent subunit vaccine or a genetically engineered killed whole-cell vaccine.

[Anti-infective treatments in urology]

OBJECTIVE

To define the terms of use of vaccines, probiotics, and cranberry in urology.

MATERIALS AND METHODS

A literature search was conducted on MEDLINE for all these treatments used in urology. Modes of action, indications in urology and adverse effects have been detailed for each treatment.

RESULTS

Vaccines have been published in urinary tract infections. Products for bacterial interference such as probiotics are also used, their properties are described. As for the cranberry widely used in recurrent urinary tract infections, efficacy and mode of action are discussed.

CONCLUSION

The anti-E. coli vaccines, cranberry and probiotics may be useful in urinary tract infection.

Host-pathogen checkpoints and population bottlenecks in persistent and intracellular uropathogenic Escherichia coli bladder infection

Bladder infections affect millions of people yearly, and recurrent symptomatic infections (cystitis) are very common. The rapid increase in infections caused by multidrug-resistant uropathogens threatens to make recurrent cystitis an increasingly troubling public health concern. Uropathogenic Escherichia coli (UPEC) cause the vast majority of bladder infections. Upon entry into the lower urinary tract, UPEC face obstacles to colonization that constitute population bottlenecks, reducing diversity, and selecting for fit clones. A critical mucosal barrier to bladder infection is the epithelium (urothelium). UPEC bypass this barrier when they invade urothelial cells and form intracellular bacterial communities (IBCs), a process which requires type 1 pili. IBCs are transient in nature, occurring primarily during acute infection. Chronic bladder infection is common and can be either latent, in the form of the quiescent intracellular reservoir (QIR), or active, in the form of asymptomatic bacteriuria (ASB/ABU) or chronic cystitis. In mice, the fate of bladder infection, QIR, ASB, or chronic cystitis, is determined within the first 24 h of infection and constitutes a putative host-pathogen mucosal checkpoint that contributes to susceptibility to recurrent cystitis. Knowledge of these checkpoints and bottlenecks is critical for our understanding of bladder infection and efforts to devise novel therapeutic strategies.

Preventing urinary tract infection: progress toward an effective Escherichia coli vaccine

Uncomplicated urinary tract infections (UTIs) are common, with nearly half of all women experiencing at least one UTI in their lifetime. This high frequency of infection results in huge annual economic costs, decreased workforce productivity and high patient morbidity. At least 80% of these infections are caused by uropathogenic Escherichia coli (UPEC). UPEC can reside side by side with commensal strains in the gastrointestinal tract and gain access to the bladder via colonization of the urethra. Antibiotics represent the current standard treatment for UTI; however, even after treatment, patients frequently suffer from recurrent infection with the same or different strains. In addition, successful long-term treatment has been complicated by a rise in both the number of antibiotic-resistant strains and the prevalence of antibiotic-resistance mechanisms. As a result, preventative approaches to UTI, such as vaccination, have been sought. This review summarizes recent advances in UPEC vaccine development and outlines future directions for the field.

Waging war against uropathogenic Escherichia coli: winning back the urinary tract

Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a substantial economic and societal burden-a formidable public health issue. Symptomatic UTI causes significant discomfort in infected patients, results in lost productivity, predisposes individuals to more serious infections, and usually necessitates antibiotic therapy. There is no licensed vaccine available for prevention of UTI in humans in the United States, likely due to the challenge of targeting a relatively heterogeneous group of pathogenic strains in a unique physiological niche. Despite significant advances in the understanding of UPEC biology, mechanistic details regarding the host response to UTI and full comprehension of genetic loci that influence susceptibility require additional work. Currently, there is an appreciation for the role of classic innate immune responses-from pattern receptor recognition to recruitment of phagocytic cells-that occur during UPEC-mediated UTI. There is, however, a clear disconnect regarding how factors involved in the innate immune response to UPEC stimulate acquired immunity that facilitates enhanced clearance upon reinfection. Unraveling the molecular details of this process is vital in the development of a successful vaccine for prevention of human UTI. Here, we survey the current understanding of host responses to UPEC-mediated UTI with an eye on molecular and cellular factors whose activity may be harnessed by a vaccine that stimulates lasting and sterilizing immunity.

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.

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.

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.

Host defense mechanisms in urinary tract infections

The host response to urinary tract infections is directed against both bacterial surface antigens, as well as bacterial products. The local response is perhaps the most important, with prevention of binding and tissue invasion as the hallmarks. Once an infection is established, the humoral immune system is most active in curtailing the damage and clearing the infecting organism. The prostate has a specialized complex of defenses that serves to reduce the incidence of infections in males.

Three approaches for laparoscopic unroofing of simple and complicated renal cysts

We report 2 cases of simple renal cysts which were marsupialized with 2 laparoscopic approaches involving either transperitoneal, with reflection of the colon medially or dissection through the mesocolon, and a case of a multilocular renal cyst which was treated by the retroperitoneal approach. Although laparoscopic unroofing of a renal cyst is a safe and effective alternative to open surgical techniques, the transperitoneal approach should only be used for simple renal cysts. The retroperitoneal approach for complicated renal cysts may be indicated if preoperative examinations exclude the possibility of malignancy.

The importance of mucosal immunology to problems in human reproduction

The field of mucosal immunology is making rapid advances towards establishing the molecular basis of mucosal defense mechanisms and the development of mucosal vaccines. Research on the mucosal immunology of male and female reproductive tract tissues is benefiting from these advances, as well as from current investigations on specialized immunologic features of the reproductive tract. This knowledge may soon be applicable to solutions for many important problems concerning human reproduction, such as fertility regulation and the current epidemic of sexually transmitted diseases, including AIDS.

Phase I clinical trial of vaginal mucosal immunization for recurrent urinary tract infection

In a phase I clinical trial to test safety and patient acceptance 25 women with a history of recurrent urinary tract infections but no identifiable anatomic abnormality received a multivalent vaccine instilled into the vagina. The vaccine contained 6 heat-killed Escherichia coli strains and 4 nonE. coli uropathogens. Only minimal adverse reactions were observed in the 5-month period following immunization. Total vaginal and urinary IgG and IgA increased significantly (p < 0.01 by repeated measures analysis of variance). Serum antibodies to some of the nonE. coli strains but not to the E. coli strains increased after vaginal immunization. While efficacy is yet to be shown, this study indicates that this vaginally applied urinary tract infection vaccine is well tolerated, and capable of increasing vaginal and urinary antibody.