Absence of Bacterial DNA in the Bladder of Patients With Interstitial Cystitis

Urinary microbiome in uncomplicated and interstitial cystitis: is there any similarity?

PURPOSE

Acute/uncomplicated cystitis is the most common bacterial infection causing inflammation in the bladder tissues and predominantly diagnosed in women. Interstitial cystitis may too, cause inflammation in the bladder but its etiology has been elusive. Even though the site and symptoms of both diseases are largely shared, state of the urinary microbiome in these disorders have not been comparatively evaluated before. The purpose of this review is to assess and qualitatively compare structure and composition of the urinary microbiome in acute/uncomplicated cystitis and interstitial cystitis.

METHODS AND RESULTS

The available literature in MEDLINE are extensively searched using keywords and screened. Pertinent evidence is carefully assessed and synthesized. We included the original studies with a cohort of medically stable, non-pregnant women with otherwise functionally normal urinary tract and excluded the original articles if the infection in a patient's cohort is accompanied by urinary syndromes such as incontinence and overactive bladder syndrome. A total of six original papers reporting on the urinary microbiome in acute cystitis and nine papers on the interstitial cystitis met the selection criteria.

CONCLUSION

The evidence we have gleaned from the literature on the urinary microbiome associated with the acute and interstitial cystitis does not point to convergence of microbiome similarities between the two diseases. More studies with direct sampling of the bladder tissues besides sampling bladder surfaces are warranted for accurate comparison of microbiome similarity between the two conditions. The future research on interstitial cystitis microbiome should include stratified cohorts with prospective design.

Alterations of microbiota in urine from women with interstitial cystitis

Background

Interstitial Cystitis (IC) is a chronic inflammatory condition of the bladder with unknown etiology. The aim of this study was to characterize the microbial community present in the urine from IC female patients by 454 high throughput sequencing of the 16S variable regions V1V2 and V6. The taxonomical composition, richness and diversity of the IC microbiota were determined and compared to the microbial profile of asymptomatic healthy female (HF) urine.

Results

The composition and distribution of bacterial sequences differed between the urine microbiota of IC patients and HFs. Reduced sequence richness and diversity were found in IC patient urine, and a significant difference in the community structure of IC urine in relation to HF urine was observed. More than 90% of the IC sequence reads were identified as belonging to the bacterial genus Lactobacillus, a marked increase compared to 60% in HF urine.

Conclusion

The 16S rDNA sequence data demonstrates a shift in the composition of the bacterial community in IC urine. The reduced microbial diversity and richness is accompanied by a higher abundance of the bacterial genus Lactobacillus, compared to HF urine. This study demonstrates that high throughput sequencing analysis of urine microbiota in IC patients is a powerful tool towards a better understanding of this enigmatic disease.

Interstitial cystitis: diagnosis and management

Interstitial cystitis/painful bladder syndrome is a chronic condition that causes debilitating bladder pain which can be associated with urgency, frequency and nocturia. Its cause is not clear and it is still a disease diagnosed by exclusion. Oral or intravesical therapies are the main stay of treatment whilst surgical procedures are reserved for refractory cases. This condition usually warrants a multidisciplinary approach for optimum outcome. This article gives an overview of the changes in definition, aetiopathogenesis and available treatments.

Assessing diversity of the female urine microbiota by high throughput sequencing of 16S rDNA amplicons

Background

Urine within the urinary tract is commonly regarded as "sterile" in cultivation terms. Here, we present a comprehensive in-depth study of bacterial 16S rDNA sequences associated with urine from healthy females by means of culture-independent high-throughput sequencing techniques.

Results

Sequencing of the V1V2 and V6 regions of the 16S ribosomal RNA gene using the 454 GS FLX system was performed to characterize the possible bacterial composition in 8 culture-negative (<100,000 CFU/ml) healthy female urine specimens. Sequences were compared to 16S rRNA databases and showed significant diversity, with the predominant genera detected being Lactobacillus, Prevotella and Gardnerella. The bacterial profiles in the female urine samples studied were complex; considerable variation between individuals was observed and a common microbial signature was not evident. Notably, a significant amount of sequences belonging to bacteria with a known pathogenic potential was observed. The number of operational taxonomic units (OTUs) for individual samples varied substantially and was in the range of 20 - 500.

Conclusions

Normal female urine displays a noticeable and variable bacterial 16S rDNA sequence richness, which includes fastidious and anaerobic bacteria previously shown to be associated with female urogenital pathology.

[Interstitial cystitis in 2008]

Interstitial cystitis (IC) is a chronic, debilitating condition that is often associated with late diagnosis and a delay in initiation of appropriate IC-specific therapy. The typical patient with interstitial cystitis (IC) is symptomatic for many years and consults multiple physicians before IC is diagnosed. These observations suggest that the clinical presentation of IC is not widely recognized. The resultant underdiagnosis may be explained in part by the nonspecific nature of IC symptoms, such as urinary urgency, frequency, nocturia and pain, as well as by the lack of an objective diagnostic test. Pelvic pain of bladder origin may refer to pain in any location in the pelvis, is affected by the menstrual cycle and flares with sexual intercourse. As a result of variations in disease definition and diagnostic criteria for interstitial cystitis (IC), the performance of epidemiologic studies has been challenging. The true prevalence of IC is much greater than the early studies suggested. Over the last decade, the recognized prevalence of IC has increased and it is consistently greater among women as compared to men.

Interstitial cystitis

Interstitial cystitis is an enigmatic and frustrating condition to manage as a physician and to cope with as a patient. Traditionally, it has been defined as a chronic sterile inflammatory disease of the bladder of unknown aetiology. However, the International Continence Society prefers the term painful bladder syndrome and it has been decided to follow this terminology and refer to the disease as painful bladder syndrome/interstitial cystitis (PBS/IC). The condition is characterized by bladder pain, urinary frequency, urgency and nocturia. The quality of life of patients with PBS/IC is significantly degraded. Its aetiology is unknown, but might involve microbiologic, immunologic, mucosal, neurogenic and other yet unidentified agents. History, physical examination, urine analysis and culture as well as cystoscopy and hydrodistension are useful diagnostic tools but the final diagnosis tends to be a diagnosis of exclusion. This article will review the major theories of aetiology for PBS/IC and discuss diagnosis as well as the current treatment options with relevance to the proposed aetiologies.

Absence of bacterial and viral DNA in bladder biopsies from patients with interstitial cystitis/chronic pelvic pain syndrome

PURPOSE

We examined bladder biopsies from women with interstitial cystitis/chronic pelvic pain syndrome (IC/CPPS) for the presence of bacterial and viral DNA sequences using polymerase chain reaction.

MATERIALS AND METHODS

Bladder biopsies were taken during cystoscopy from patients under investigation for IC/CPPS, or controls undergoing colposuspension for stress incontinence. Biopsies were snap frozen to -70C. After DNA extraction, polymerase chain reaction (PCR) using specific primers for the hypoxanthine-guanine phosphoribosyl transferase gene confirmed the presence of human DNA. PCR for bacterial and viral gene sequences was performed using specific primers. Positive reactions were repeated to confirm the signal.

RESULTS

A total of 92 patients with IC/CPPS (12 who met the National Institute of Diabetes and Digestive and Kidney Diseases criteria and 80 who did not) and 91 controls were recruited. PCR for hypoxanthine-guanine phosphoribosyl transferase gene was positive in all samples. PCR for the 16S ribosomal RNA gene, as well as for adenovirus, cytomegalovirus, herpes simplex virus types I and II, human papillomavirus (all subtypes) and Chlamydia trachomatis were negative in all samples.

CONCLUSIONS

IC/CPPS is not associated with persistence of viral and bacterial DNA in the bladder. A chronic infective etiology for the condition is excluded by these findings.

Interstitial cystitis

Interstitial cystitis (IC) is a debilitating chronic inflammatory disorder of the bladder. It affects predominantly middle-aged Caucasian women. The diagnosis, made from the combination of symptoms, cystoscopic findings and bladder biopsies, is often delayed in the gynaecology setting because of a low index of suspicion. The pathophysiology is incompletely understood, although mast cell activation, altered bladder epithelial permeability and sensory afferent nerve up-regulation are thought to play key roles. Recent theories include the role of an antiproliferative factor. A wide assortment of therapies is available and many more are under trial. Until the causes and pathogenesis of IC are unraveled, mainstream medical treatment will remain palliative and cystectomy with urinary diversion, the only potential cure. In addition to our long experience on managing this disorder, we present a comprehensive review of the current thoughts on the aetiology and management of IC.

Treatment of interstitial cystitis

Although the symptoms of interstitial cystitis (IC)--a debilitating, chronic disease characterized by urinary urgency and frequency, and bladder and pelvic pain on bladder filling--are easily confused with those of urinary tract infections, there is an absence of an underlying infection, and antibiotic therapy is of no therapeutic benefit. Severe cases of this disorder, which affects mainly women, can have a great negative impact on the quality of life of patients because of extreme urinary frequency. The diagnosis of IC is difficult and should be based on patient history, physical examination, and cystoscopy. A large number of pharmacologic treatments have been used to treat this condition with limited success, including pentosan polysulfate, heparin, antihistamines, tricyclic antidepressants, intravesical dimethyl sulfoxide, and bacille Calmette-Guérin. Among the potentially effective new treatment modalities currently under investigation are suplatast tosilate, resiniferatoxin, botulinum toxin, and gene therapy to modulate the pain response. As knowledge of the pathogenesis of IC increases through intensified research, the ability to provide effective treatment to patients with this disease will improve.

Is interstitial cystitis an infectious disease?

Interstitial cystitis (IC) is a chronic bladder disorder of unknown aaetiology. Although several investigators have attempted to identify an infectious cause for IC, none has yet been found. Our own studies to search for an infectious cause discovered instead, a toxic factor in the urine of approximately 95% of IC patients that is made by and inhibits, the normal proliferation of bladder epithelial cells. Additional research is necessary to determine whether this factor is encoded by the eucaryotic cells themselves or an unidentified intracellular microorganism.

Current investigations and treatment of interstitial cystitis

Interstitial cystitis (IC) is a chronic condition characterized by a constellation of symptoms such as urinary frequency, nocturia, urinary urgency, suprapubic pressure, and bladder and pelvic pain. Since its original description, the etiology of the disorder has remained unknown despite intense investigations. The International Cystitis Association (ICA) and the National Institutes of Arthritis, Diabetes, Digestive and Kidney Diseases (NIDDK) have been instrumental in supporting the United States Interstitial Database (ICDB) and foster research to study the disorder. The NIDDK developed criteria to ensure that all groups of patients treated would be relatively comparable. However, many patients who would be clinically considered to have IC do not fulfill all the NIDDK criteria. Many clinical criteria for the diagnosis of IC, such as the presence of glomerulations and the intravesical potassium chloride test, are being challenged. The epidemiology of the disorder is not well established, but there are an estimated 700,000 cases of IC in the United States. Numerous pathophysiologic mechanisms have been proposed, but none have been proven. There is no representative animal model of IC. Both the oral and intravesical treatments of IC are noncurative, and few are based on a plausible mechanism or scientific evidence. Surgical treatment should be considered with extreme caution; it is the last therapeutic option because failure rate can be substantial.

Pathophysiology of interstitial cystitis

Despite being described over 80 years ago, interstitial cystitis remains a disease of undetermined aetiology and poor treatment outcomes. Generally agreed diagnostic criteria of this condition, which occurs primarily in females, are frequency, urgency and pain, a low-capacity hypersensitive bladder, and mucosal haemorrhages and tearing on bladder distention. Although current theories of pathophysiology are predominantly conjecture, important elements of the disease process are increased afferent and efferent neuronal activity, an excess of inflammatory mediators, increased epithelial permeability and possibly reduced bladder vascularity. Improved treatment outcome will follow a better understanding of pathophysiology.

Polymerase chain reaction amplification of bacterial 16S rRNA genes from cold-cup biopsy forceps

PURPOSE

In looking for a possible infectious cause for interstitial cystitis (IC), we previously determined that bladder tissue specimens from both IC patients and controls were uniformly positive by polymerase chain reaction assay (PCR) for bacterial 16S ribosomal RNA genes from various genera including Escherichia, Propionobacterium, Acinetobacter, and Salmonella. We therefore determined whether the biopsy forceps might be contaminated with bacterial DNA.

MATERIALS AND METHODS

A total of 23 samples were obtained following disinfection of 6 cold-cup bladder biopsy forceps (2 to 5 specimens from each forceps over a period of 19 months). DNA was extracted from each sample, and PCR performed using nested primers from a highly conserved region of the bacterial 16S rRNA gene. Amplified DNA was purified and sequenced, and the sequences obtained were compared with bacterial rRNA gene sequences recorded in GenBank.

RESULTS

Thirteen of 23 forceps specimens were positive by PCR for bacterial DNA, including at least one rinse from each of the 6 forceps. In comparison, none of 9 negative control specimens (sterile distilled water put into tubes and processed in the same manner as forceps rinses) had detectable bacterial DNA. Sequence data indicated the presence of a predominant organism in 12 of the 13 positive specimens, with >95% homology to DNA from several different genera of bacteria including Escherichia, Propionobacterium, Stenotrophomonas and Pseudomonas.

CONCLUSIONS

These data indicate that reusable bladder biopsy forceps are frequently contaminated with bacterial DNA. Tissue specimens procured with such instruments therefore are inappropriate sources to look for the presence of bacterial pathogens by PCR.

Interstitial cystitis

Interstitial cystitis (IC) is a multifactorial syndrome with symptoms of pelvic or perineal pain, urinary frequency and urgency. The etiologies are unknown, but several theories have been proposed. Diagnosis is often delayed because most of the conventional evaluation is normal. Pelvic examination is normal except for bladder tenderness. Urodynamics are normal except for increased bladder sensitivity and low capacity. Urinalysis, urine culture and office cystoscopy are also normal. The diagnostic test is cystoscopy under anesthesia with bladder distension. Small submucosal hemorrhages (glomerulations) or ulcers appear after distension. Many empiric treatments have been proposed for IC. None is universally effective, and so treatments are tried sequentially until good symptom relief is achieved. Bladder distension gives excellent (but transient) relief in some patients, especially those with severe bladder inflammation (who also tend to be older). A variety of oral, intravesical and adjunctive treatments are also described.

A hypothesis for the etiology of interstitial cystitis based upon inhibition of bladder epithelial repair

Interstitial cystitis (IC) is a chronic bladder disease characterized by distinct bladder mucosal abnormalities, for which the etiology is unknown. Although the epidemiology of this disorder is similar to that of bacterial cystitis, prospective studies using sensitive culture techniques and polymerase chain reaction assay for a variety of microorganisms have failed to identify a specific infectious etiology for IC. We have identified a low-molecular-weight peptide in the urine of IC patients that inhibits the proliferation of normal bladder epithelial cells in vitro. We therefore propose a model of IC, in which this peptide inhibits bladder epithelial regeneration following damage (such as that caused by bacterial cystitis). The chronically damaged epithelium is prone to colonization with various microorganisms, and the resulting exposure to these microorganisms, other urinary antigens, and/or damaged epithelial cells prompts the low-level inflammatory response commonly seen in this disorder.

Interstitial cystitis and the gynecologist

Interstitial cystitis (IC) is a predominantly female condition with the presenting symptoms of frequency of micturition and pain. The diagnosis is confirmed by bladder visualization at cystoscopy during filling, emptying, and redistension. The epidemiology, proposed etiologies, and current therapies for interstitial cystitis are discussed. The condition of IC is poorly understood and has no specific histological characteristics. However, there is much that can be offered to the IC sufferer to relieve or cure her symptoms. It is hoped that the recent decade of increasing research activity will be fruitful in answering questions of etiology and pathogenesis, and offering hope for new therapies and ultimately cure.

Polymerase chain reaction amplification of bacterial 16S rRNA genes in interstitial cystitis and control patient bladder biopsies

PURPOSE

Several characteristics of the chronic bladder disease called interstitial cystitis (IC) suggest an infectious etiology. However, a single causative organism has not been convincingly cultured in vitro, and DNA for a variety of microorganisms has been found inconsistently in bladder biopsies from IC patients. We therefore looked for a possible bacterial cause for IC by using a sensitive nested PCR assay on cystoscopic bladder biopsy specimens obtained from IC patients and controls.

MATERIALS AND METHODS

Bladder biopsies were obtained at cystoscopy from 6 IC patients and 6 controls. DNA was extracted from these specimens and PCR with 2-round amplification performed using nested primers from a highly conserved region of the bacterial 16s rRNA gene. Amplified DNA was purified and sequenced using the Sequenase PCR Product Sequencing Kit, and the sequences obtained were compared with bacterial rRNA gene sequences recorded in GenBank.

RESULTS

Biopsy specimens from all 6 patients and 6 controls were positive by PCR for DNA encoding bacterial 16s rRNA. Sequence data indicated a predominant microorganism in 10 of the 12 specimens, with > 95% homology to DNA from several different genera of bacteria including Acinetobacter, Propionobacterium, Salmonella, and Escherichia. None of the organisms identified by PCR had been cultured from tissue or urine obtained simultaneously from these persons, using sensitive culture techniques.

CONCLUSIONS

These data indicate no difference between IC patients and controls in the proportion of bladder biopsies with PCR positivity or the type(s) of organism present, providing additional evidence that IC is not associated with infection by a particular type of bacterium.

Detection of eubacteria in interstitial cystitis by 16S rDNA amplification

OBJECTIVE

To determine what role non-culturable microorganisms play in the etiology of interstitial cystitis (IC).

MATERIALS AND METHODS

Thirty patients fulfilling NIH criteria for the diagnosis of interstitial cystitis and sixteen control patients with culture negative urine gave written informed consent and underwent bladder biopsy. Polymerase chain reaction (PCR) using two sets of universal primers for bacterial 16S rDNA was performed on urine from the cystoscope and on a cold cup bladder biopsy specimen. Of the PCR positive bladder biopsies, three patients with interstitial cystitis and three controls were randomly selected and cloned. Ten clones from each were sequenced and putative taxonomic assignments made.

RESULTS

12/26 (46%) IC and 5/12 (42%) control urine specimens and 16/30 (53%) and 9/15 (60%) bladder biopsies were PCR positive, respectively. The bacterial populations in the two patient groups tested appeared to be different based upon analysis of the 16S rRNA sequences.

CONCLUSIONS

Both IC and control patients had non-culturable bacteria in their bladders. A random sampling of the two populations revealed that the bacterial populations are different, suggesting a possible link between one or more bacterial species and IC.

Interstitial cystitis: a critique of current concepts with a new proposal for pathologic diagnosis and pathogenesis

Interstitial cystitis (IC) has continued to be an unresolved problem in clinical urology despite intense investigation over the past 16 or more years. Its etiology and pathogenesis are still undetermined, and its pathologic diagnosis is essentially one of exclusion, with no specific or clear criteria. In this review, current concepts of the etiology/pathogenesis and pathology are critically analyzed, new pathologic observations summarized, and a proposal of neurogenic inflammation as the primary pathogenetic factor is presented in the context of all currently available information. The popular postulate attributing IC to a deficient or defective glycosaminoglycan urothelial surface layer is not substantiated by morphologic, experimental, clinical, or therapeutic observations. Although the consensus seems to discount an infectious etiology, there is sufficient evidence that a microbial factor-short of a bona fide clinical infection-may have a role. Both autoimmunity and mast cell infiltration also appear to have a role, despite the lack of evidence that either is involved as the primary etiologic factor. Claims that the so-called feline urologic syndrome may represent a natural animal model of IC are shaky. As it now stands, there is no natural or induced animal model that duplicates IC as it occurs in humans. No specific or diagnostic light microscopic pathologic features are provided by either routine histopathology or immunohistochemistry. Increasingly, it has been recognized that detrusor mast cell count has little or no diagnostic value. On the other hand, electron microscopy has provided important new observations: (a) presence of mast cells, activated by piecemeal degranulation, in close proximity to intrinsic nerves-particularly in suburothelium: (b) distinctive pathologic changes in urothelium, suburothelium, and muscularis in biopsy samples obtained after diagnostic bladder hydrodistension; (c) constant associated changes in venules, capillaries, and neural elements in the same biopsy samples; and (d) diffuse involvement of bladder wall, with the most evident and profound pathologic changes in posthydrodistension biopsy samples obtained from cystoscopically obvious lesions (glomerulations). These features are sufficiently distinctive to allow definitive pathologic diagnosis of IC, and provide a firm basis for primary involvement of neurogenic inflammation in its pathogenesis. A proposal is presented regarding the mechanisms invoked by neurogenic inflammation. This proposal revolves around sensory nerve excitation, the release of neuropeptides, and activated differential secretion of potent mast cell mediators. This proposal can account for the heterogeneity and variability of observed pathologic features, and upholds the tacit acceptance of IC as a disease of pluricausal etiology and multifactorial pathogenesis.