Impact of concurrent antimicrobial therapy on catheter-associated urinary tract infection

Biofilm-Producing Bacteria and Risk Factors (Gender and Duration of Catheterization) Characterized as Catheter-Associated Biofilm Formation

Background

A catheter-associated urinary tract infection (CA-UTI) is preceded by biofilm formation, which is related to several risk factors such as gender, age, diabetic status, duration of catheterization, bacteriuria before catheterization, virulence gene factor, and antibiotic usage.

Aims

This study aims to identify the microbial composition of catheter samples, including its corresponding comparison with urine samples, to determine the most important risk factors of biofilm formation and characterize the virulence gene factors that correlate with biofilm formation.

Methods

A longitudinal cross-sectional study was conducted on 109 catheterized patients from September 2017 to January 2018. The risk factors were obtained from the patients' medical records. All catheter and urine samples were cultured after removal, followed by biomass quantification. Isolate identification and antimicrobial susceptibility testing were performed using the Vitex2 system. Biofilm-producing bacteria were identified by the Congo Red Agar (CRA) method. A PCR test characterized the virulence genes of dominant bacteria (E. coli). All data were collected and processed for statistical analysis.

Results

Out of 109 catheterized patients, 78% of the catheters were culture positive, which was higher than those of the urine samples (37.62%). The most common species isolated from the catheter cultures were Escherichia coli (28.1%), Candida sp. (17.8%), Klebsiella pneumoniae (15.9%), and Enterococcus faecalis (13.1%). E. coli (83.3%) and E. faecalis (78.6%) were the main isolates with a positive CRA. A statistical analysis showed that gender and duration prior to catheterization were associated with an increased risk of biofilm formation (p < 0.05).

Conclusion

E. coli and E. faecalis were the most common biofilm-producing bacteria isolated from the urinary catheter. Gender and duration are two risk factors associated with biofilm formation, therefore determining the risk of CAUTI. The presence of PapC as a virulence gene encoding pili correlates with the biofilm formation. Biofilm-producing bacteria, female gender, duration of catheterization (more than five days), and PapC gene presence have strong correlation with the biofilm formation. To prevent CAUTI, patients with risk factors should be monitored by urinalysis tests to detect earlier the risk of biofilm formation.

A strategy to control colonization of pathogens: embedding of lactic acid bacteria on the surface of urinary catheter

Indwelling urinary catheterization is one of the major causes of urinary tract infection (UTI) in hospitalized patients worldwide. A catheter serves as a surface for the colonization and formation of biofilm by UTI-related pathogenic bacteria. To combat the biofilm formation on its surface, several strategies have already been employed such as coating it with antibiofilm and antimicrobial compounds. For instance, the application of lactic acid bacteria (LAB) offers a potential strategy for the treatment of biofilm formation on the surface of the urinary catheter due to its ability to kill the pathogenic bacteria. The killing of pathogenic bacteria by LAB occurs via the production of antimicrobial compounds such as lactic acid, bacteriocin, and hydrogen peroxide. LAB also displays a competitive exclusion mechanism to prevent the adhesion of pathogens on the surfaces. Hence, LAB has been extensively applied as a bacteriotherapy to combat infectious diseases. Several strategies have been employed to attach LAB to a surface, but its easy detachment during long time exposure becomes one of the drawbacks in its application. Here, we have proposed a novel strategy for its adhesion on the surface of the urinary catheter with the utilization of mannose-specific adhesin (Msa) protein in a way similar as uropathogenic bacteria interacts between Msa present on the tip of the type I fimbriae/pilus and the mannose moieties on the host epithelial cell surfaces. KEY POINTS: • Urinary tract infection (UTI) is one of the common hospital-acquired infections, which is associated with the application of an indwelling urinary catheter. • Based on the competitive exclusions properties of LAB, attachment of the LAB on the catheter surface would be a promising approach to control the formation of pathogenic biofilm. • The strategy employed for the adhesion of LAB is via a covalent interaction of its mannose-specific adhesin (Msa) protein to the mannose residues grafted on the catheter surface.

Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America

Asymptomatic bacteriuria (ASB) is a common finding in many populations, including healthy women and persons with underlying urologic abnormalities. The 2005 guideline from the Infectious Diseases Society of America recommended that ASB should be screened for and treated only in pregnant women or in an individual prior to undergoing invasive urologic procedures. Treatment was not recommended for healthy women; older women or men; or persons with diabetes, indwelling catheters, or spinal cord injury. The guideline did not address children and some adult populations, including patients with neutropenia, solid organ transplants, and nonurologic surgery. In the years since the publication of the guideline, further information relevant to ASB has become available. In addition, antimicrobial treatment of ASB has been recognized as an important contributor to inappropriate antimicrobial use, which promotes emergence of antimicrobial resistance. The current guideline updates the recommendations of the 2005 guideline, includes new recommendations for populations not previously addressed, and, where relevant, addresses the interpretation of nonlocalizing clinical symptoms in populations with a high prevalence of ASB.

Asymptomatic Bacteriuria and Bacterial Interference

Asymptomatic bacteriuria is very common. In healthy women, asymptomatic bacteriuria increases with age, from <1% in newborns to 10% to 20% of women age 80 years, but is uncommon in men until after age 50 years. Individuals with underlying genitourinary abnormalities, including indwelling devices, may also have a high frequency of asymptomatic bacteriuria, irrespective of age or gender. The prevalence is very high in residents of long-term-care facilities, from 25% to 50% of women and 15% to 40% of men. Escherichia coli is the most frequent organism isolated, but a wide variety of other organisms may occur. Bacteriuria may be transient or persist for a prolonged period. Pregnant women with asymptomatic bacteriuria identified in early pregnancy and who are untreated have a risk of pyelonephritis later in pregnancy of 20% to 30%. Bacteremia is frequent in bacteriuric subjects following mucosal trauma with bleeding, with 5% to 10% of patients developing severe sepsis or septic shock. These two groups with clear evidence of negative outcomes should be screened for bacteriuria and appropriately treated. Asymptomatic bacteriuria in other populations is benign and screening and treatment are not indicated. Antimicrobial treatment has no benefits but is associated with negative outcomes including reinfection with antimicrobial resistant organisms and a short-term increased frequency of symptomatic infection post-treatment. The observation of increased symptomatic infection post-treatment, however, has led to active investigation of bacterial interference as a strategy to prevent symptomatic episodes in selected high risk patients.

Urinary tract infection in the neurogenic bladder

There is a high incidence of urinary tract infection (UTI) in patients with neurogenic lower urinary tract function. This results in significant morbidity and health care utilization. Multiple well-established risk factors unique to a neurogenic bladder (NB) exist while others require ongoing investigation. It is important for care providers to have a good understanding of the different structural, physiological, immunological and catheter-related risk factors so that they may be modified when possible. Diagnosis remains complicated. Appropriate specimen collection is of paramount importance and a UTI cannot be diagnosed based on urinalysis or clinical presentation alone. A culture result with a bacterial concentration of ≥10(3) CFU/mL in combination with symptoms represents an acceptable definition for UTI diagnosis in NB patients. Cystoscopy, ultrasound and urodynamics should be utilized for the evaluation of recurrent infections in NB patients. An acute, symptomatic UTI should be treated with antibiotics for 5-14 days depending on the severity of the presentation. Antibiotic selection should be based on local and patient-based resistance patterns and the spectrum should be as narrow as possible if there are no concerns regarding urosepsis. Asymptomatic bacteriuria (AB) should not be treated because of rising resistance patterns and lack of clinical efficacy. The most important preventative measures include closed catheter drainage in patients with an indwelling catheter and the use of clean intermittent catheterization (CIC) over other methods of bladder management if possible. The use of hydrophilic or impregnated catheters is not recommended. Intravesical Botox, bacterial interference and sacral neuromodulation show significant promise for the prevention of UTIs in higher risk NB patients and future, multi-center, randomized controlled trials are required.

A Pilot Study on Prevention of Catheter-Related Urinary Tract Infections with Fluoroquinolones

The objective of this multicenter, randomized, controlled, parallel group trial was to evaluate the efficacy of levofloxacin 250 mg oral, once daily (LVFX), placebo one tablet oral once daily (Placebo [P] group) and ciprofloxacin (CPFX) 500 mg oral, twice daily (single blind), prophylaxis in preventing bacteriuria (> or = 10(3) CFU/ml) in post-surgical catheterized patients. In the modified intention-to-treat (M-ITT) population of the 82 enrolled patients, negative bacteriuria was observed in 92% of LVFX group, in 80% of P group and in 100% of CPFX group while in the per-protocol (PP) population figures were: 100%, 86.4% and 100% respectively. Only one symptomatic urinary tract infection and one surgical wound infection were observed in the P group. Both drugs were well tolerated, showing a safety profile comparable to placebo. The high frequency of negative bacteriuria in the placebo group sounds encouraging as it underlines that the adoption of closed urinary drainage system catheters in hospital setting may reduce the frequency of hospital-acquired infections.

Antibiotic prescribing practices for catheter urine culture results

BACKGROUND

The literature suggests that positive results of catheter urine cultures frequently lead to unnecessary antimicrobial prescribing, which therefore represents an important target for stewardship.

OBJECTIVE

To assess the appropriateness of antibiotic prescribing in response to the results of urine cultures from patients with indwelling urinary catheters.

METHODS

This retrospective study was conducted at a tertiary care centre and involved adults with indwelling urinary catheters from whom urine specimens were obtained for culture. Patients with positive or negative culture results were identified from microbiology laboratory reports. The medical records of consecutive patients were screened to select a sample of 80 inpatients (40 per group). Abstracted patient histories were independently evaluated by an expert panel of 3 infectious diseases consultants blinded to the decisions of prescribers and of fellow panelists. The primary end point was concordance of each patient's treatment decision (with respect to the indication) between the expert panel (based on majority agreement, i.e., at least 2 of the 3 expert panelists) and the prescriber. The secondary end points were unnecessary days of therapy and selected outcomes over a predefined period after urine was obtained for culture.

RESULTS

A total of 591 charts were screened to generate the targeted number of patients. Baseline demographic characteristics were comparable for the 2 groups, except antibiotic exposure before urine collection was significantly more frequent for the group with negative culture results. The treatment decision was concordant in 40% (16/40) of the patients with a positive culture result and 85% (34/40) of those with a negative culture result (p < 0.001). The most common reason for discordance was administration of antibiotics when not indicated (23 of 24 patients with a positive result and 5 of 6 patients with a negative result), which accounted for 165 and 32 unnecessary days of therapy per 1000 inpatient-days, respectively (p < 0.001). Adverse effects occurred in 2 of the 23 patients with a positive result who received antibiotics that were not indicated.

CONCLUSIONS

Appropriateness of antibiotic prescribing, as measured by concordance of decisions between the expert panel and prescribers, was more common among patients with negative urine culture results than among those with positive results. However, there is an opportunity to improve prescribing for both groups through antimicrobial stewardship initiatives. Unnecessary days of therapy and adverse effects were more common in patients with a positive culture result.

Culture-dependent and -independent investigations of microbial diversity on urinary catheters

Catheter-associated urinary tract infection is caused by bacteria, which ascend the catheter along its external or internal surface to the bladder and subsequently develop into biofilms on the catheter and uroepithelium. Antibiotic-treated bacteria and bacteria residing in biofilm can be difficult to culture. In this study we used culture-based and 16S rRNA gene-based culture-independent methods (fingerprinting, cloning, and pyrosequencing) to determine the microbial diversity of biofilms on 24 urinary catheters. Most of the patients were catheterized for <30 days and had undergone recent antibiotic treatment. In addition, the corresponding urine samples for 16 patients were cultured. We found that gene analyses of the catheters were consistent with cultures of the corresponding urine samples for the presence of bacteria but sometimes discordant for the identity of the species. Cultures of catheter tips detected bacteria more frequently than urine cultures and gene analyses; coagulase-negative staphylococci were, in particular, cultured much more often from catheter tips, indicating potential contamination of the catheter tips during sampling. The external and internal surfaces of 19 catheters were separately analyzed by molecular methods, and discordant results were found in six catheters, suggesting that bacterial colonization intra- and extraluminally may be different. Molecular analyses showed that most of the species identified in this study were known uropathogens, and infected catheters were generally colonized by one to two species, probably due to antibiotic usage and short-term catheterization. In conclusion, our data showed that culture-independent molecular methods did not detect bacteria from urinary catheters more frequently than culture-based methods.

An evaluation of the management of asymptomatic catheter-associated bacteriuria and candiduria at The Ottawa Hospital

BACKGROUND

Asymptomatic catheter-associated urinary tract infections (CAUTIs) are common in hospitalized patients. They are associated with a low incidence of sequelae and morbidity, and in most patients resolve spontaneously on removal of the catheter. As a result, it is not recommended that asymptomatic catheter-associated bacteriuria or candiduria be treated with antimicrobial agents while the catheter remains in place because it may lead to the evolution of resistant flora.

OBJECTIVE

To assess the current management of patients with CAUTIs with respect to antimicrobial therapy at The Ottawa Hospital and the University of Ottawa Heart Institute, Ottawa, Ontario.

METHODS

A prospective observational study over a period of 26 consecutive days was conducted at The Ottawa Hospital (General and Civic campuses) and the University of Ottawa Heart Institute. Inpatients with an indwelling catheter, a positive urine culture and the absence of UTI signs or symptoms were assessed. Patients were followed for five days to determine whether antimicrobials were prescribed.

RESULTS

From March 3 to March 28, 2003, 29 of 119 patients screened met inclusion criteria. Of these 29 patients, 15 (52%) were prescribed antimicrobials and were therefore considered to be inappropriately managed. Differences were observed between the appropriate and inappropriate management groups in terms of duration of stay to positive urine culture and whether yeast or bacteria were isolated from the culture.

CONCLUSION

Antimicrobial agents were prescribed in over one-half of CAUTI cases, contrary to recommendations from the literature. Education is required to bring this strongly supported recommendation into clinical practice.

Recognition and prevention of healthcare-associated urinary tract infections in the intensive care unit

Urinary tract infection is the most common healthcare-associated infection in the intensive care unit and predominantly occurs in patients with indwelling urinary catheters. The predominant microorganisms causing catheter-associated urinary tract infection (CAUTI) in the intensive care unit are enteric Gram-negative bacilli, enterococci, Candida species, and Pseudomonas aeruginosa. Multidrug resistance is a significant problem in urinary pathogens. Duration of catheterization is the most important risk factor for development of CAUTI. Diagnosis, particularly in the intensive care unit setting, is very difficult, as asymptomatic bacteriuria may be difficult to differentiate from symptomatic CAUTI. In general, asymptomatic bacteriuria should not be treated, and treatment of CAUTI often requires removal of the catheter along with systemic antimicrobial therapy. General strategies for prevention of CAUTI apply to all healthcare-associated infections and include measures such as adherence to hand hygiene. Targeted strategies for prevention of CAUTI include limiting the use and duration of urinary catheterization, using aseptic technique for catheter insertion, and adhering to proper catheter care.

Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America

Guidelines for the diagnosis, prevention, and management of persons with catheter-associated urinary tract infection (CA-UTI), both symptomatic and asymptomatic, were prepared by an Expert Panel of the Infectious Diseases Society of America. The evidence-based guidelines encompass diagnostic criteria, strategies to reduce the risk of CA-UTIs, strategies that have not been found to reduce the incidence of urinary infections, and management strategies for patients with catheter-associated asymptomatic bacteriuria or symptomatic urinary tract infection. These guidelines are intended for use by physicians in all medical specialties who perform direct patient care, with an emphasis on the care of patients in hospitals and long-term care facilities.

Clinical relevance of single administration of prophylactic antimicrobial agents against febrile events after removal of ureteral stents for patients with urinary diversion or reconstruction

OBJECTIVE

To assess the efficacy of antimicrobial prophylaxis when removing ureteral stents after urinary diversion or reconstruction and to establish the most appropriate prophylactic protocol to prevent febrile events.

METHODS

We retrospectively investigated the incidence of febrile events in the two studies. Study 1 consisted of 39 patients who received antimicrobial prophylaxis and 31 who did not. Study 2 included 48 patients who were given oral fluoroquinolone (FQ) and 27 who had intramuscular injection of an aminoglycoside (AG).

RESULTS

In study 1, the incidence of febrile events was significantly lower in patients receiving antimicrobial prophylaxis (26.0%) than in those not receiving it (51.6%) (P = 0.025, chi(2) test). In study 2 there was a 13% incidence of febrile events, which was much lower than the incidence found in study 1. The incidence of these events was similar between the two study groups, being 13% for those receiving FQ and 15% for those receiving AG.

CONCLUSIONS

Prophylactic administration of antimicrobials reduces the incidence of febrile events after removal of ureteral stents. Both FQ and the AG are equally effective in this setting.

Risk factors for nosocomial urinary tract-related bacteremia: a case-control study

BACKGROUND

Risk factors for bacteremia in patients with hospital-acquired bacteriuria are largely unknown. Given the morbidity and costs associated with nosocomial bacteremia, determining risk factors could enhance the safety of hospitalized patients.

METHODS

We conducted a case-control study within the Veterans Affairs Puget Sound Health Care System. A patient hospitalized between 1984 and 1999 from whom a urine culture and a blood culture grew the same organism > or =48 hours after admission was considered a case. Control patients were those with significant bacteriuria detected > or =48 hours after admission who did not have a positive blood culture. We used logistic regression to determine independent risk factors for bacteremia.

RESULTS

There were 95 cases and 142 controls. Independent, statistically significant predictors of bacteremia included immunosuppressant therapy within 14 days of bacteriuria (odds ratio [OR], 8.13); history of malignancy (OR, 1.94); male sex (OR, 1.88); cigarette use in the past 5 years (OR, 1.26); number of hospital days before bacteriuria (OR, 1.03); and antibiotic use within 3 days of bacteriuria (OR, 0.76). Corticosteroid use within 7 days of bacteriuria predicted bacteremia in patients <70 years old (OR, 14.24). Similarly, patients <70 years old were more likely to develop bacteremia if they had diabetes mellitus (OR, 6.19).

CONCLUSION

Delineating risk factors for nosocomial urinary tract-related bacteremia can help target appropriate preventive practices at the highest risk patients.

Prophylactic use of antimicrobials in commonly performed outpatient urologic procedures

An antimicrobial is an agent capable of killing or inhibiting the growth of a micro-organism. Antimicrobial prophylaxis encompasses efforts to prevent postprocedure infections through the use of an antimicrobial agent before, and, in some cases, for a limited time after a procedure. A thorough history and physical examination are essential to identify host factors that increase a patient's risk for postprocedural infection. Risk-modifying factors include age, anatomy, geographical area of residence, immune and nutritional status, cardiac valve integrity, prosthetic joints, the presence of indwelling hardware and distant infectious wounds. Prophylaxis for the most common urologic outpatient procedures can be attained with oral trimethoprim-sulfamethoxazole or fluoroquinolone administered between 2 h and 30 min before a procedure. Special consideration for the type and duration of prophylaxis should be given to patients with moderate to severe cardiac valvular conditions and recently inserted prosthetic joints.

Catheter-Related Urinary Tract Infection

Indwelling urinary catheters are used frequently in older populations. For either short- or long-term catheters, the infection rate is about 5% per day. Escherichia coli remains the most common infecting organism, but a wide variety of other organisms may be isolated, including yeast species. Bacteria tend to show increased resistance because of the repeated antimicrobial courses. Urinary tract infection (UTI) usually follows formation of biofilm on both the internal and external catheter surface. The biofilm protects organisms from both antimicrobials and the host immune response. Morbidity from UTI with short-term catheter use is limited if appropriate catheter care is practised. In patients with long-term catheters, fever from a urinary source is common with a frequency varying from 1 per 100 to 1 per 1000 catheter days. Long-term care facility residents with chronic indwelling catheters have a much greater risk for bacteraemia and other urinary complications than residents without catheters. Asymptomatic catheter-acquired UTI should not be treated with antimicrobials. Antimicrobial treatment does not decrease symptomatic episodes but will lead to emergence of more resistant organisms. For treatment of symptomatic infection, many antimicrobials are effective. Wherever possible, antimicrobial selection should be delayed until culture results are available. Whether to administer initial treatment by an oral or parenteral route is determined by clinical presentation. If empirical therapy is required, antimicrobial selection is based on variables such as route of administration, anticipated infecting organism and susceptibility, and patient tolerance. Renal function, concomitant medications, local formulary and cost may also be considered in selection of the antimicrobial agent. The duration of therapy is usually 10-14 days, but patients who respond promptly and in whom the catheter must remain in situ may be treated with a shorter 7-day course to reduce antimicrobial pressure. Relevant clinical trials are necessary to define optimal antimicrobial regimens for the management of catheter-acquired UTI. Prevention of catheter-acquired UTI and its complications is a major goal. With short-term catheters, avoiding their use or limiting the duration of use to as short a time as possible are the most effective prevention strategies. Maintaining a closed drainage system and adhering to appropriate catheter care techniques will also limit infection and complications. As the duration of catheterisation is the principal determinant of infection with long-term indwelling catheters, it is not clear that any interventions can decrease the prevalence of bacteriuria in this setting. Catheter flushing or daily perineal care do not prevent infection and may, in fact, increase the risk of infection. Complications of infection may be prevented by giving antibacterials for bacteriuria immediately prior to any invasive urological procedure, and by avoiding catheter blockage, twisting or trauma. The major focus of future advances in prevention of catheter-acquired UTI is the development of biomaterials resistant to biofilm formation. There is substantial current research addressing this issue, but current catheter materials all remain susceptible to biofilm formation.

Catheter-associated urinary tract infections in intensive care units

The purpose of this review is to analyze literature concerning the diagnosis, prevention, and management of catheter-associated urinary tract infection (CAUTI) occurring in patients hospitalized in the intensive care unit (ICU). Analysis was performed from personal and "Pubmed" data, crossing the following keywords: "urinary tract infection", "catheter', and "intensive care unit". Few clinical trials including ICU patients were found despite the abundance of expert opinions. There is no consensus on the use of urinary reagent tests for diagnosis. The prevention of CAUTI in ICU patients does not require expensive devices. Neither complex closed drainage systems nor silver-coated urinary catheters have demonstrated efficacy in comparative randomized clinical trials. Bladder irrigation should not be used, except when an obstruction of the catheter is highly likely. The administration of prophylactic antimicrobial therapy, although effective in reducing the incidence of urinary bacteria, cannot be recommended in ICU patients. The management of CAUTI in ICU patients has not been evaluated in clinical trials. The level of evidence provided in this field is weak, and underlines the need for randomized studies to improve management of patients.

Biofilms and catheter-associated urinary tract infections

Urinary catheter-related infections are commonly seen in several different patient populations and lead to substantial morbidity. The overall health care costs caused by these infections are sizable given how often urinary catheters are used in acute care settings, extended care facilities, and in persons with injured spinal cords. Recent attention has appropriately focused on biofilm development on the catheter surface because biofilm has important implications for the pathogenesis, treatment, and prevention of catheter-related infection. Because the most important risk factor for infection is duration of catheterization, indwelling urethral catheterization should be avoided or at least limited whenever possible. Additional methods to prevent this infection include aseptic insertion and maintenance use of a closed drainage system, anti-infective catheters in patients at high-risk for infection, and systemic antibiotics in select patients. Alternative urinary collection strategies may be appropriate in certain patient groups. Specifically, condom catheters should be considered in men likely to be adherent with this urinary collection method, suprapubic catheters should be considered in patients requiring long-term indwelling drainage, and intermittent catheterization seems appropriate in patients with injured spinal cords. Future research should focus on additional methods for preventing this common infection.

Impact of hospital-wide surveillance on hospital-acquired infections in an acute-care hospital in the Netherlands

The goal of surveillance is to identify hospital-acquired infections (HAI) and risk factors, to apply targeted interventions and to evaluate their effect in an ongoing system. Continuing active surveillance in a 270-bed acute-care hospital is being performed on clinical patients, excluding day-care. The period 1984-1997 is described here. Specific surveillance-based interventions included the introduction of antimicrobial prophylaxis in gynaecology patients with postoperative urinary tract catheters and inpatients scheduled for appendicectomy and hysterectomy. General measures included education, implementation of protocols, feedback of surgeon-specific infection rates. In total, 3545 HAI were found in 13 years of surveillance. The incidence was 4.7/100 admissions and 4. 5/1000 patient days. Age-specific incidences ranged from 1.3 in the age-category 1-14 years, to 10.2 in patients aged 75 years and above. If age-specific incidences had remained at their 1984 level, over 3000 additional infections would have occurred, affecting all age groups except those up to 14 years. The distribution of types of infections differed between services. Following the targeted interventions, the rate of infections in gynaecology decreased from 19.4 per 1000 patient days in 1984 to 2.4 per 1000 patient days in 1996. The rates of wound infection following appendicectomy and hysterectomy decreased by 69% and 82%, respectively, in the period following the institution of antimicrobial prophylaxis. Over 4000 micro-organisms were isolated from the HAI; multi-resistant strains were isolated sporadically. We conclude that hospital-wide surveillance of hospital-acquired infections provides appropriate targets for interventions tailored to the specific needs of the hospital. The impact of such interventions can readily be documented from the surveillance data.

Do antimicrobials have a role in preventing septicaemia following instrumentation of the urinary tract?

Urinary tract instrumentation is a significant cause of septicaemia. Review of the literature suggests that selective use of antimicrobials would reduce the risk of septicaemia as this varies between patients and with procedures. Antimicrobial prophylaxis is indicated for patients at high risk of endocarditis, or who are neutropenic. For patients without these risk factors, it is indicated for open, transurethral, or certain forms of laser prostatectomy or trans-rectal prostate biopsy. For cystoscopy, antimicrobials are indicated for patients with preoperative bacteriuria or a preoperative indwelling catheter. Single dose aminoglycosides or oral fluoroquinolones are the agents of choice with the exception of the prevention of endocarditis, where combinations active against streptococci are recommended. For other instrumentations, the risk of antimicrobial toxicity probably outweighs the benefits and a risk-reduction strategy is recommended. Further studies are required to provide definitive answers in many of these areas.

UTI in patients with urethral catheters: an audit tool

This article presents an audit tool for the evaluation of practice relating to urinary tract infection in hospital patients with indwelling urethral catheters. It has been formulated primarily because urinary tract infection is a known complication of catheterization, and because studies have shown practitioners' knowledge in this area to be poor. Although health professionals have an obligation to ensure their practice is evidence based, this requires substantial time and skills in critical appraisal. The standard presented here is based on evidence from an extensive literature review on how best to minimize urinary tract infection during catheter insertion, meatal hygiene and management of the drainage system. The audit tool offers the potential for improved practice and demonstration of clinical effectiveness through measurable reduction in rates of urinary tract infection. Moreover, it provides an ideal opportunity for nurses to take the lead in clinical audit activity, which is so often medically led. The supplementary information will also provide a useful guide for nurses to undertake and initiate clinical audit activity in the future.

A practical guide to the management of complicated urinary tract infection

Complicated urinary tract infections are infections in the setting of structural or functional abnormalities of the genitourinary tract. They encompass a wide variety of clinical syndromes and anticipated outcomes. The infecting micro-organisms isolated are more varied and demonstrate a higher prevalence of antimicrobial resistance in complicated compared to uncomplicated urinary tract infections. The usual duration of therapy is 7 to 14 days, although comparative trials to define optimal treatment duration are lacking. Long term success of antimicrobial treatment is dependent upon whether or not the underlying genitourinary abnormality can be corrected. Treatment of complicated urinary tract infections will usually be successful and may be permanent if the underlying abnormality can be corrected. If the underlying abnormality cannot be corrected, failure rates of 50% at 4 to 6 weeks following therapy are expected. Antimicrobial agents are similar to those used to treat uncomplicated urinary tract infection. Certain agents, such as nitrofurantoin, should be avoided for individuals with renal failure. No specific agent or class of agents has consistently demonstrated greater therapeutic efficacy where the infecting organism is susceptible to the given agent.

Management of bacterial urinary tract infections in adults

OBJECTIVE

To provide a comprehensive review of the diagnosis and therapeutic management considerations in patients with urinary tract infections (UTIs).

DATA SOURCES

A MEDLINE search was used to identify pertinent English language literature, including reviews. Infectious disease textbooks were used for background information.

STUDY SELECTION

Clinical trials evaluating drug therapy in a variety of patient populations with UTIs were reviewed.

DATA EXTRACTION

Background information was obtained from comprehensive reviews. Drug dosing strategies and efficacy comparisons were extracted from the investigations in this area.

DATA SYNTHESIS

Information was processed to provide general guidelines and resources for practitioners to use in managing UTIs.

CONCLUSIONS

There are a number of useful antibiotics for the management of UTIs. The distinctions between infection severity and underlying risk factors within a given population influence the appropriateness of drug selection and duration of treatment.

Nosocomial catheter-associated bacteriuria: a clinical trial comparing two closed urinary drainage systems

We compared the time of onset and incidence of nosocomial bacteriuria between two different closed urinary drainage systems: a simple closed drainage system containing an antireflux valve ('Urias A-4') and a complex closed drainage system ('Curity Infection Control System') incorporating: (1) a preconnected, coated catheter, (2) a tamper discouraging seal at the catheter-drainage tubing junction, (3) a drip chamber, (4) an antireflux valve, (5) a hydrophobic drainage bag vent and (6) a povidone-iodine releasing cartridge in line with the outlet tube of the urine collection bag. 181 non-bacteriuric patients, requiring catheter drainage for more than 48 h, were assigned by chance to either of the two systems. Bacteriological monitoring of bladder urines of the enrolled patients was performed every 24 h by establishing viable counts and identification of all microorganisms. No differences in the onset and incidence of nosocomial bacteriuria between the two urine drainage system groups were noted. We conclude that additional complex features aimed at preventing intraluminal spread of bacteria did not reduce the risk of urinary tract infection, compared to a simple closed urinary drainage system.

London after Tomlinson. Care in the capital: what needs to be done

One of the aims of the Tomlinson report is to shift more care from the secondary to the primary sector in London. But the primary sector is already underresourced and overloaded. The capital has a heterogeneous population which often makes inappropriate demands on general practitioners. Many premises are inadequate and there are insufficient support staff. David Metcalfe emphasises that London is special and that the shift will not become a reality unless these problems are tackled. He suggests the establishment of different models of practice centres which could treat some of the patients who now go to accident and emergency departments. Some would be the night emergency service base, some would have primary care beds, and each would have a different mix of specialist support.

Diagnosis and management of urinary tract infection in adults

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Prophylactic ciprofloxacin for catheter-associated urinary-tract infection

Patients receiving antibiotics during bladder drainage have a lower incidence of urinary-tract infections compared with similar patients not on antibiotics. However, antibiotic prophylaxis in patients with a urinary catheter is opposed because of the fear of inducing resistant bacterial strains. We have done a double-blind, placebo-controlled trial of prophylactic ciprofloxacin in selected groups of surgical patients who had postoperative bladder drainage scheduled to last for 3 to 14 days. Patients were randomly assigned to receive placebo (n = 61), 250 mg ciprofloxacin per day (n = 59), or 500 mg ciprofloxacin twice daily (n = 64) from postoperative day 2 until catheter removal. 75% of placebo patients were bacteriuric at catheter removal compared with 16% of ciprofloxacin-treated patients (relative risk [RR] [95% CI] 4.7 [3.0-7.4]). The prevalence of pyuria among placebo patients increased from 11% to 42% while the catheter was in place; by contrast, the rate of pyuria was 11% or less in patients receiving ciprofloxacin (RR 4.0 [2.1-7.3]). 20% of placebo patients had symptomatic urinary-tract infections, including 3 with septicaemia, compared with 5% of the ciprofloxacin groups (RR 4.0 [1.6-10.2]). Bacteria isolated from urines of placebo patients at catheter removal were mostly species of enterobacteriaceae (37%), staphylococci (26%), and Enterococcus faecalis (20%), whereas species isolated from urines of ciprofloxacin patients were virtually all gram-positive. Ciprofloxacin-resistant mutants of normally sensitive gram-negative bacteria were not observed. Ciprofloxacin prophylaxis is effective and safe in the prevention of catheter-associated urinary tract infection and related morbidity in selected groups of patients requiring 3 to 14 days of bladder drainage.