Mechanisms of urinary tract infection

SWOT and Root Cause Analyses of Antimicrobial Resistance to Oral Antimicrobial Treatment of Cystitis

Nearly 150 million cases of urinary tract infections (UTIs) are reported each year, of which uncomplicated cystitis triggers > 25% of outpatient prescriptions of oral antimicrobial treatment (OAT). OAT aids immune cells infiltrating the urothelium in eliminating uropathogens capable of invading the urothelium and surviving hyperosmotic urine. This self-evident adaptability of uropathogens and the short interval between the introduction of Penicillin and the first report of antimicrobial resistance (AMR) implicate AMR as an evolutionary conserved heritable trait of mutant strains selected by the Darwinian principle to survive environmental threats through exponential proliferation. Therefore, AMR can only be countered by antimicrobial stewardship (AMS) following the principle of the five Ds-drug, dose, duration, drug route, and de-escalation. While convenient to administer, the onset of the minimum inhibitory concentration (MIC) for OAT in urine leaves a window of opportunity for uropathogens to survive the first contact with an antimicrobial and arm their descendant colonies with AMR for surviving subsequent higher urine antimicrobial levels. Meanwhile, the initial dose of intravesical antimicrobial treatment (IAT) may be well above the MIC. Therefore, the widespread clinical use of OAT for cystitis warrants an analysis of the strengths, weaknesses, opportunity, and threats (SWOTs) and a root cause analysis of the AMR associated with OAT and IAT.

Case report: Emphysematous cystitis due to Escherichia coli infection with the extension of gas into multiple locations in two non-diabetic dogs: a computed tomographic diagnosis and successful management

Emphysematous cystitis is an extremely rare, complicated urinary tract infection with the presence of gas in the bladder wall and lumen caused by gas-producing bacterial infections. A 7-year-old spayed female pomeranian dog was presented with a 3-day history of hematuria and pollakiuria (case 1), and a 9-year-old spayed female jindo dog was presented with a 4-day history of intermittent hematuria (case 2). Imaging modalities, including radiography, ultrasonography, and computed tomography, and bacterial culture tests were used for the diagnosis. Emphysematous cystitis due to Escherichia coli infection with the extension of gas into multiple locations was identified in both cases. Based on the results of antibiotic susceptibility testing, systemic antibiotics were initiated. Both animals had an excellent response to antibiotic treatment, and the clinical signs of the gas collection were completely resolved within ~1 month after treatment initiation. This response was sustained without recurrence in the follow-up period. This case report describes clinical details of extremely rare canine cases of emphysematous cystitis with the extension of gas into multiple locations and evaluates the clinical efficacy of antibiotic therapy.

Adult Neurogenic Lower Urinary Tract Dysfunction and Intermittent Catheterisation in a Community Setting: Risk Factors Model for Urinary Tract Infections

A risk factor model for urinary tract infections in patients with adult neurogenic lower urinary tract dysfunction performing clean intermittent catheterisation was developed; it consists of four domains, namely, (1) general (systemic) conditions in the patient, (2) individual urinary tract conditions in the patient, (3) routine aspects related to the patient, and (4) factors related to intermittent catheters per se. The conceptual model primarily concerns patients with spinal cord injury, spina bifida, multiple sclerosis, or cauda equina where intermittent catheterisation is a normal part of the bladder management. On basis of several literature searches and author consensus in case of lacking evidence, the model intends to provide an overview of the risk factors involved in urinary tract infections, with specific emphasis to describe those that in daily practice can be handled and modified by the clinician and so come to the benefit of the individual catheter user in terms of fewer urinary tract infections.

What explains anorectal chlamydia infection in women? Implications of a mathematical model for test and treatment strategies

OBJECTIVES

Female anorectal Chlamydia trachomatis (chlamydia) infections are common irrespective of recent anal sex. We explored the role of anorectal infections in chlamydia transmission and estimated the impact of interventions aimed at improved detection and treatment of anorectal infections.

METHODS

We developed a pair compartmental model of heterosexuals aged 15-29 years attending STI clinics, in which women can be susceptible to or infected with chlamydia urogenitally and/or anorectally and men urogenitally. Transmission probabilities per vaginal and anal sex act, together with an autoinoculation probability, were estimated by fitting to anatomic site-specific prevalence data (14% urogenital; 11% anorectal prevalence). We investigated the 10-year reduction in female chlamydia prevalence of interventions (universal anorectal testing of female STI clinic attendees or doxycycline use for urogenital chlamydia) relative to continued current care (anorectal testing on indication and doxycycline for anorectal and azithromycin for urogenital chlamydia).

RESULTS

The transmission probability per anal sex act was 5.8% (IQR 3.0-8.3%), per vaginal sex act 2.0% (IQR 1.7-2.2%) and the daily autoinoculation probability was 0.7% (IQR 0.5-1.0%). More anorectal chlamydia infections were caused by autoinoculation than by recent anal sex. Universal anorectal testing reduced population prevalence modestly with 8.7% (IQR 7.6-9.7%), yet the reduction was double that of doxycycline use for urogenital infections (4.3% (IQR 3.5-5.3%)) relative to continued current care.

CONCLUSIONS

Autoinoculation between anatomic sites in women might play a role in sustaining high chlamydia prevalence. A shift to more anorectal testing of female STI clinic attendees may be considered for its (albeit modest) impact on reducing prevalence.

Toileting behaviour and related health beliefs among Chinese female nurses

AIMS

To investigate the toileting behaviours that female nurses used to empty their bladders, health beliefs related to toileting behaviour and the relationships between the health beliefs and toileting behaviour based on the Health Belief Model.

METHODS

A stratified cluster sampling strategy was used to recruit 636 female nurses from three tertiary hospitals in China. Reliable and valid questionnaires were used to assess female nurses' toileting behaviour and health beliefs related to toileting behaviour. The structural equation model was applied to explore the relationships between health belief constructs and toileting behaviour.

RESULTS

The most common unhealthy toileting behaviour was that of delayed voiding. More than half of the nurses (53.6%) often or always delayed emptying their bladders when they were busy. Approximately one-third of female nurses often or always crouched over the toilet to empty their bladders when not at home. Nearly two-thirds often or always worried about the cleanliness of public toilets. Of all the participants, 67.5% of female nurses had at least one type of lower urinary tract symptom (LUTS); however, the majority did not believe that they were susceptible to these symptoms. Moreover, they had misconceptions that premature voiding would reduce the risk, relieve the symptoms and prevent the recurrence of LUTS.

CONCLUSIONS

Many female nurses engaged in unhealthy toileting behaviours and might not know what types of toileting behaviours are healthy. Nurses play an important role in patient education and are a major source of health information for society. It is particularly important to look more closely at toileting behaviour among nurses and implement education and training to promote healthy toileting behaviour and, in turn, optimise bladder health.

Impact of behaviour and lifestyle on bladder health

Bladder conditions, including UTI, UI, and bladder cancer, are highly prevalent and affect a wide range of populations. There are a variety of modifiable behavioral and lifestyle factors that influence bladder health. Some factors, such as smoking and obesity, increase the risk or severity of bladder conditions, whereas other factors, such as pelvic floor muscle exercise, are protective. Although clinical practice may be assumed to be the most appropriate ground for education on behavioral and lifestyle factors that influence bladder health, it is also crucial to extend these messages into the general population through public health interventions to reach those who have not yet developed bladder conditions and to maximize the prevention impact of these behaviors. Appropriate changes in these factors have the potential for an enormous impact on bladder health if implemented on a population-based level.

Factors implicated in pathogenesis of urinary tract infections in neurogenic bladders: some revered, few forgotten, others ignored

AIMS

To comprehensively review factors implicated in the pathogenesis of urinary tract infection in patients with neurogenic bladders, and to stimulate research, especially in the somewhat ignored and forgotten areas of this important clinical subject.

METHODS

In addition to reviewing relevant articles on pubmed, some important articles from previous times which were not available online were also procured and reviewed.

RESULTS

Intrinsic defence mechanisms including protective flora, anti-adherence mechanisms, urothelial, and immunological responses to bacterial binding and the blood supply to the urinary bladder may be impaired in patients with neurogenic bladders. Further, bacterial washout mechanisms may be compromised as a result of inefficient voiding, reflux, and altered hydrokinetics. Finally, catheterization itself contributes to urinary tract infection in patients with neurogenic bladders.

CONCLUSIONS

In order to address the issue of urinary tract infection in patients with neurogenic bladders, multiple factors need to be looked into and corrected. Further research is required, especially in the area of compromised host defence mechanisms. An individualized approach, which attempts to optimize each factor is recommended.

Influence of the great earthquake in the Chuetsu district on patients managing urination with clean intermittent self-urethral catheterization

Natural disasters cause several medical problems for victims, especially for physically challenged people. The great earthquake in the Chuetsu district in Niigata Prefecture that occurred on October 23, 2004 caused serious damage in the disaster area. We investigated the effect of this earthquake on patients managing urination with clean intermittent self-urethral catheterization (CIC) using a questionnaire by mailing. The questionnaire was collected from 86 patients (60 men, 25 women, one sex unknown). The average age was 64.6 years old (males 64.1, females 65.8). By the first week after the earthquake, the patients with urological symptoms made up 3.8% of subjects surveyed. All of the patients had insufficient fluid intake, and did not live in their own homes, or perform CIC at home, for the period of time after the earthquake. During disasters, it is important that we secure CIC patients a living space, where they can perform CIC, with sufficient drinking water.

Reducing Urinary Tract Infections among Female Clean Room Workers

OBJECTIVES

A higher prevalence of urinary tract infection (UTI) was observed among clean room workers than among others in our previous study in 2001. We implemented intervention programs for reducing UTI and evaluated their effects 2 years later.

METHODS

We conducted an intervention study in four factories in the industrial park where the previous study was conducted and recruited participants from women workers who received annual health examinations at the clinic of the park. The intervention included health education programs during the new employee orientation and seasonal on-the-job training. We also implemented other measures, including placing posters in the workplace and disseminating knowledge of UTI prevention through e-mail and oral communications. One-on-one education was provided to workers who were found to have UTI in the previous study.

RESULTS

All the 1666 qualified workers, including 1414 clean room workers and 252 nonclean room workers, agreed to participate. We found a similar prevalence (both 0.8%) of symptomatic UTIs (patients with clinical symptoms, such as voiding frequency, urgency, and burning sensation during voiding) in clean room and nonclean room workers. In the 366 participants who also participated in the previous study, we found a significant decrease in the prevalence of UTI (from 9.8% to 1.6%) and significant increases in the prevalence of water intake and urine voiding, three times or more during a shift (p < 0.001 for all McNemar tests).

CONCLUSIONS

The interventions had achieved behavior modification and decreases in the prevalence of UTI.

Pathogenesis of urinary tract infections: a review

Pathogenesis of urinary tract infections (UTIs) is not well-understood. In this paper, we review the current understanding of UTIs, particularly in relationship to individuals using intermittent catheterization. Relationships exist between the human host, infectious agent and the environment. In the human host, the urethra connects the bladder to potential infectious agents on the perineum. A high-pressure zone exists within the urethra at a point where the urethra passes through the urogenital diaphragm. This zone creates a natural barrier to ascent of organisms colonized in the distal urethra and the bladder itself has natural defences against invading organisms. The interaction of host defences with bacteria (infectious agent) determines whether or not the bacteria persist. A small number of bacteria and some types of bacteria are controlled more effectively by natural bladder defence mechanisms and frequent bladder emptying than a large number of bacteria. Escherichia coli, coliforms and enterococci are considered common bacterial causes of UTIs and are found in high numbers on the perineum. Intermittent catheterization is an effective way of bladder emptying but as an invasive procedure it remains a risk factor in the development of UTI.

Sacral bladder denervation for treatment of detrusor hyperreflexia and autonomic dysreflexia

OBJECTIVES

Detrusor hyperreflexia after spinal cord injury may cause urinary incontinence and chronic renal failure. In patients refractory to conservative treatment and not eligible for ventral sacral root stimulation for electrically induced micturition, we investigated the therapeutic value of sacral bladder denervation as a stand-alone procedure.

METHODS

Nine patients (8 men and 1 woman) between 21 and 58 years old (mean 30.2) with traumatic suprasacral spinal cord lesions underwent sacral bladder denervation for treatment of detrusor hyperreflexia and/or autonomic dysreflexia.

RESULTS

Detrusor hyperreflexia and autonomic dysreflexia were eliminated in all cases. Bladder capacity increased from 177.8 +/- 39.6 to 668.9 +/- 64.3 mL; intravesical pressure decreased from 89.3 +/- 19.1 to 20.2 +/- 2.7 cm H(2)O. For facilitating clean intermittent catheterization (CIC), 4 patients received a continent vesicostomy in a second-stage procedure; one of them in combination with bladder augmentation. Four patients empty their bladder by way of urethral CIC. One completely tetraplegic patient has an indwelling urethral catheter. In the 5 patients with autonomic dysreflexia, the systolic blood pressure was lowered from 196 +/- 16.9 to 124 +/- 9.3 mm Hg and the diastolic blood pressure from 114 +/- 5.1 to 76 +/- 5.1. The annual frequency of urinary tract infections decreased from 9 +/- 1.2 to 1.8 +/- 0.7. In all patients, renal function remained stable.

CONCLUSIONS

In selected patients with detrusor hyperreflexia and/or autonomic dysreflexia, sacral bladder denervation is a valuable treatment option. It is only moderately invasive in nature, requires neither sophisticated nor expensive medical equipment, and is an attractive alternative to urinary diversion using intestinal segments.

Effects of ligation of the internal iliac artery on blood flow to the bladder and detrusor function in rat

Ischaemia induced by atherosclerosis is a common cause of disorders in the elderly, including impairment of bladder function. To evaluate experimentally the effects of ischaemia on detrusor function, we performed infusion cystometry and evaluated the morphologic findings in the bladder of the rat. Blood flow to the bladder of the rat was evaluated with a Doppler flowmeter before and after the unilateral or bilateral ligation of the internal iliac arteries. Reevaluation was done at one and two weeks after surgery. Bladder function was studied by infusion cystometry performed in vivo under urethane anaesthesia. Finally, histological examination was performed. Blood flow at mid-dorsal wall of the control bladder was inversely related to intravesical volume. Unilateral or bilateral ligation of the internal iliac arteries decreased blood flow to the bladder, which showed a complete recovery two weeks postoperatively. Infusion cystometry of the ischaemic bladder with bilateral ligation of the internal iliac arteries demonstrated a decrease in voiding pressure, an increase in bladder capacity, and an increase in pressure at which micturition was initiated vs. the control. The bladder with unilateral ligation of the artery showed a decrease in voiding pressure, with no change in the other parameters. Histological examination indicated that the bilateral ischaemia and ischaemic side of unilateral ischaemia led to a degeneration of the mucosa, and severe oedema in submucosal and muscle layers one week postoperatively. Degeneration of smooth muscle was predominant at 2 weeks. Contralateral side of the unilaterally ischaemic bladder showed oedema and congestion of the submucosa and smooth muscle. Ligation of the internal iliac artery decreased blood flow to the bladder significantly, which resulted in smooth muscle degeneration. Consequently, in vivo voiding pressure was impaired in the ischaemic bladder.

Thirst at work--an occupational hazard?

Of 1492 teachers 791 (53%) responded to a survey addressing whether voiding habits at work or behavioral factors influenced by this occupation predisposed women to urinary tract infection. The mean number of voids during the work day was 2.7 +/- 1.4; 24.5% voided infrequently (never or only once) and 26.5% voided four or more times during the work day; 15.8% had had a urinary tract infection in the preceding year. Half of the respondents made a conscious effort to drink less while working, to avoid needing to use the toilet. There was no association between the prevalence of urinary tract infection and the number of voids or infrequent voiding at work. Compared to women who drank the volume they desired at work, those who drank less had a 2.21-fold higher risk (95% CI 1.45-3.38) of urinary tract infection after controlling for being parous, voiding infrequently at work, and urge incontinence. Further study is warranted to determine whether modification of behavioral factors at work can reduce the incidence of urinary tract infections. If this association holds, public policy must be changed to allow workers more adequate access to toilet facilities.

Effect of ischemia of the rabbit bladder on Ca-Mg-activated ATP-ase activity

This investigation is concerned with the effect of ischemia on the activity of Ca-Mg-stimulated ATP-ase in rabbit bladder tissue. White New Zealand male rabbits were used for the experiments. Ischemia was produced by clamping of the vesical arteries. After 1 and 2 hours the clamps were removed, and the animals were sacrificed 2 days later. The bladders were removed, and the muscle and mucosal parts of the bladders were separated. In some experiments with 2-hour ischemia the animals were allowed to recover for 7 days. Homogenates were made of the muscle and mucosal tissue and separated by differential centrifugation into three parts: 1) an initial particulate fraction obtained by low-speed centrifugation; 2) a supernate fraction free of mitochondria; and 3) a mitochondrial-rich fraction. ATP-ase activity was determined in the different fractions in the presence of magnesium or calcium as the activating ion, and the results were expressed as nmols/mg protein/minute. The following results were obtained: with the supernates, ischemia was found to produce a marked inhibition of enzyme activity that was large and significant in muscle tissue after 1 hour and in mucosal tissue after 2 hours. Seven days after termination of 1 hour of ischemia, the ATP-ase activity of the muscle fraction had been partially restored towards normal. Activity of ATP-ase when measured in the particulate fraction was less sensitive to the effect of ischemia; a significant diminution of enzyme activity in preparations from muscle was seen only after 2 hours of ischemia, and no inhibition was observed with mucosal tissue. ATP-ase of muscle mitochondria was severely inhibited by ischemia, and the effect of 1 hour of ischemia was not reversed 7 days after the insult. Mitochondria from mucosal tissue were affected to only a small extent by ischemia. In all cases, results were similar whether magnesium or calcium was used for activation of the enzyme.

The effects of short-term in-vivo ischemia on the contractile function of the rabbit urinary bladder

The proper functioning of any smooth muscle requires adequate perfusion with oxygen and nutrients. Ischemia compromises both these factors and results in dysfunction, the extent depending on the degree and duration of ischemia. This study determined the effects of one, two and four weeks in vivo ischemia on the capacity, compliance and contractile function of the rabbit urinary bladder. Morphological changes were also studied with light microscopy. Different degrees of ischemia were achieved as follows. In the unilateral group the vesical artery was tied on one side and the animals were sacrificed at one week or two weeks. In the bilateral group the vesical arteries on both sides were tied and the animals were sacrificed one week later. In the bilateral staged group the vesical artery was tied on one side and after one week the contralateral artery was ligated, and the animals sacrificed one week after the second procedure. Muscle strips were studied for contractile response, with a distinction being made between the ipsilateral and contralateral side of vessel ligation in the unilateral group. The results were as follows. 1) In the unilateral group there was a 72% reduction in the contractile response of the dome of the bladder to bethanecol on the side of vessel ligation and a 32% reduction on the contralateral side. The response to methoxamine on the base was reduced by 44%, with no difference between the ipsilateral and contralateral side. 2) Bilateral vessel ligation resulted in a 97% reduction in contractile response to bethanechol on the dome and a 75% in the response of the base to methoxamine. 3) Staged bilateral ligation resulted in a 69% reduction in the contractile response of the dome to bethanechol and a 18% reduction in the response of the base to methoxamine. Ischemia caused a marked reduction in the compliance and capacity of the bladder in all the three groups, with the most marked changes in the bilateral group. Multiple spontaneous contractions were noted in the three groups during the filling phase of the cystometrograms. Histological features correlated well with the functional changes in the different groups.

Hematuria in the burned child

Hematuria is a frequent complication in burn patients, but its clinical significance has not been reported. The incidence, etiologies, treatment, and outcome of hematuria in 1,785 burn patients treated from 1964 to 1983, have been reviewed. Ninety-one patients had hematuria (greater than 15 RBC/HPF with unspun urine). There were five main causes: urinary infections (UTI), 50 cases; renal calculi (RC), 14 cases, including 3% and 5% total body surface area burn patients; catheter trauma, 7 cases; renal vein thrombosis (RVT), 5 cases; and acute renal failure (ATN), 4 cases. Ten patients died in the UTI group, five with Candida as the infecting organism. No RC patients died, but two required surgical extraction of their stones. This incidence of RC may be due to large intake of dairy products and antacids and to prolonged immobilization. The catheter trauma group had no deaths and was the youngest group. One RVT patient was diagnosed clinically and successfully treated surgically. The other three were diagnosed at necropsy. The ATN patients all developed renal failure late as part of multiple organ system failure and all died. We conclude hematuria is a serious finding in burn patients and prompt diagnosis of its etiology and treatment are essential for maintaining renal function and patient survival.

Justification of closed intermittent urinary catheter irrigation/instillation: a review of current research and practice

Urinary tract infections secondary to urinary instrumentation continue to affect over 400,000 patients per year in the USA. While the debate continues over the effectiveness of catheter/bladder irrigation or instillation, these procedures continue to be indicated for certain conditions. Inconsistencies in how these procedures are carried out often depend on the type of catheter used, frequency of the procedure, and equipment available. This review article looks at the available literature on pathogenesis of urinary tract infections and specific literature on irrigation techniques and outcomes. This information is summarized and recommendations are made for adoption of a well-supported procedure, which also provides more cost-effective care. Proposals are made for further research involving use of this procedure.

Heparin inhibition of increased bacterial adherence following overdistension, ischemia and partial outlet obstruction of the rabbit urinary bladder

While it is well established clinically that urinary tract infection in the presence of outflow obstruction may be associated with difficulty in eradicating bacteria, it is not clear whether this is secondary to the presence of residual urine volume or other local effects of the obstruction such as attenuation of the intrinsic antibacterial defense mechanisms of the mucosal surface. Experiments in our laboratory and others over the past several years have demonstrated that the primary antibacterial defense mechanism of the bladder is the antiadherence effect of the bladder surface mucin layer. Additional studies have shown that heparin can duplicate this antiadherence activity of bladder mucin. The present report demonstrates that one hour of overdistension or ischemia and one week of partial outlet obstruction cause a functional defect in the intrinsic antiadherence effect of the bladder mucosa as evidenced by increased bacterial adherence. This defect can be reversed by heparin exposure prior to bacterial challenge. These results indicate that partial outlet obstruction and its potential sequelae such as overdistension and, particularly, mucosal ischemia, have dramatic adverse effects on the intrinsic antiadherence defense mechanism of the bladder. These effects can be reversed by intravesical exposure to an exogenous anionic polyelectrolyte (heparin).

The contractile and metabolic effects of acute ischemia on the rabbit urinary bladder

The present study determined the effect of 1 hour of in vivo ischemia on the response of the rabbit urinary bladder to specific autonomic agonists and on the intracellular adenosine triphosphate content. A 48 per cent decrease in the contractile response of the base to the alpha agonist methoxamine was noted. A 42 per cent decrease in the response of the bladder body to bethanechol was found. Neither tissue improved significantly after a 1-week recovery period. Ischemia caused an immediate 80 per cent decrease in the intracellular adenosine triphosphate content that improved to 50 per cent of control with a 1-week recovery period. Although the site of the defect is not definitely identified, acute ischemia resulted in a decreased contractile response that could result in bladder dysfunction.

Effect of lumbar epidural analgesia on lower urinary tract function in the immediate postpartum period

Urodynamic investigations including cystometry and electronic simultaneous urethro-cystometry were made in 27 primiparae between 2 and 5 days after delivery to assess possible effects of lumbar epidural analgesia on the function of the lower urinary tract. Three groups of patients were studied: 11 patients had vaginal delivery without epidural analgesia, 11 patients with similar obstetrical characteristics were delivered vaginally with epidural analgesia, and five others were delivered by caesarean section under epidural analgesia. The group of patients who were delivered vaginally under epidural analgesia had a significantly higher incidence (n = 4) of hypotonic bladders as determined by cystometry than the group without epidural analgesia (n = 0), (P less than 0.05). The maximum cystometric capacity was significantly greater (P less than 0.05) in the group who delivered vaginally with epidural analgesia than in the group without epidural analgesia, as well as the caesarean section group (with epidural analgesia), (P less than 0.01). Possible side effects of epidural analgesia implied by these results are discussed and a method for surveillance of urethrovesical function both during labour and after parturition is proposed.