A large randomized clinical trial of a silver-impregnated urinary catheter: lack of efficacy and staphylococcal superinfection

Effects of Baseplates of Orthodontic Appliances with in situ generated Silver Nanoparticles on Cariogenic Bacteria: A Randomized, Double-blind Cross-over Clinical Trial

AIM

Polymethyl-methacrylate (PMMA) is commonly used primarily for baseplates of orthodontic appliances (BOA). The activities of cariogenic bacteria in biofilm on these surfaces may contribute to dental caries, gingival inflammation and periodontal disease. The PMMA incorporated with nanoparticles of silver (NanoAg-I-PMMA) and NanoAg in situ in PMMA (NanoAg-IS-PMMA) have been shown to control the growth of cariogenic bacteria, but clinical trial of anti-cariogenic application of these novel materials in orthodontics has not been evaluated. The main aim of the study is to compare the clinical effectiveness of using NanoAg-IS-PMMA and NanoAg-I-PMMA for construction of new BOA in inhibiting the planktonic growth and biofilm formation of the cariogenic bacteria.

MATERIALS AND METHODS

Twenty four patients with a median age of 12.6 years (7-15) harboring Streptococcus mutans, Streptococcus sobrinus and Lactobacillus acidophilus as well as Lactobacillus casei participated in the randomized, double-blind, cross-over study. The experimental BOA, NanoAg-IS-BOA and NanoAg-I-BOA, contained 0.5% w/w NanoAg while the control BOA was standard PMMA. Antibacterial effect of NanoAg-IS-BOA and NanoAg-I-BOA was assessed against test cariogenic bacteria by planktonic and biofilm bacterial cells growth inhibition.

RESULTS

The average levels of test cariogenic bacteria in saliva decreased about 2 to 70 fold (30.9-98.4%) compared to baseline depending on the microorganism type and test BOA. Biofilm inhibition analysis demonstrated that NanoAg-I-BOA and NanoAg-IS-BOA inhibited the biofilm of all test bacteria by 20.1 to 79.9% compared to BOA. NanoAg-IS-BOA had a strong anti-biofilm effect against S. mutans, S. sobrinus and L. casei. However, NanoAg-I-BOA showed only slight anti-biofilm effects on test bacteria. Most notably, at all period of the clinical trial, NanoAg-IS-BOA showed a higher antibacterial activity than NanoAg-I-BOA.

CONCLUSION

Based on the novel data that presented here, the NanoAg-IS-BOA had strong antimicrobial activity in the planktonic phase and subsequent biofilm formation of the cariogenic bacteria.

CLINICAL SIGNIFICANCE

Wearing of NanoAg-IS-BOA has the potential to minimize dental plaque formation and caries during orthodontic treatment.

Risk factors for urinary catheter associated bloodstream infection

OBJECTIVES

Urinary catheter associated bloodstream infection (UCABSI) causes significant morbidity, mortality and healthcare costs. We aimed to define the risk factors for UCABSI.

METHODS

A case-control study was conducted at two Australian tertiary hospitals. Patients with urinary source bloodstream infection associated with an indwelling urinary catheter (IDC) were compared to controls with an IDC who did not develop urinary source bloodstream infection.

RESULTS

There were 491 controls and 67 cases included in the analysis. Independent statistically significant risk factors for the development of UCABSI included insertion of the catheter in operating theatre, chronic kidney disease, age-adjusted Charlson comorbidity index, accurate urinary measurements as reason for IDC insertion and dementia. IDCs were inserted for valid reasons in nearly all patients, however an appropriate indication at 48 h post-insertion was found in only 44% of patients. Initial empiric antibiotics were deemed inappropriate in 23 patients (34%).

CONCLUSION

To our knowledge, this is the first study to look specifically at the risk factors for bloodstream infection in urinary catheterised patients. Several risk factors were identified. IDC management and empiric management of UCABSI could be improved and is likely to result in a decreased incidence of infection and its complications.

Strategies to Prevent Catheter-Associated Urinary Tract Infections in Acute Care Hospitals

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections. The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their catheter-associated urinary tract infection (CAUTI) prevention efforts. Refer to the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America “Compendium of Strategies to Prevent Healthcare-Associated Infections” Executive Summary and Introduction and accompanying editorial for additional discussion.

1. Burden of CAUTIs

a. Urinary tract infection is the most common hospital-acquired infection; 80% of these infections are attributable to an indwelling urethral catheter.

b. Twelve to sixteen percent of hospital inpatients will have a urinary catheter at some time during their hospital stay.

c. The daily risk of acquisition of urinary infection varies from 3% to 7% when an indwelling urethral catheter remains in situ.

2. Outcomes associated with CAUTI

a. Urinary tract infection is the most important adverse outcome of urinary catheter use. Bacteremia and sepsis may occur in a small proportion of infected patients.

b. Morbidity attributable to any single episode of catheterization is limited, but the high frequency of catheter use in hospitalized patients means that the cumulative burden of CAUTI is substantial.

c. Catheter use is also associated with negative outcomes other than infection, including nonbacterial urethral inflammation, urethral strictures, and mechanical trauma.

Strategies to prevent catheter-associated urinary tract infections in acute care hospitals: 2014 update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their catheter-associated urinary tract infection (CAUTI) prevention efforts. This document updates “Strategies to Prevent Catheter-Associated Urinary Tract Infections in Acute Care Hospitals,” published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA). the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

Modification of silicone elastomer with zwitterionic silane for durable antifouling properties

Biofouling on medical devices generally causes adverse complications, such as thrombosis, infection, and pathogenic calcification. Silicone is a widely used material for medical applications. Its surface modification typically encounters undesirable "hydrophobic recovery", leading to deterioration of surface engineering. In this study, we developed a stable superhydrophilic zwitterionic interface on polydimethylsiloxane (PDMS) elastomer by covalent silanization of sulfobetaine silane (SBSi) to resist nonspecific adsorption of bacteria, proteins, and lipids. SBSi is a zwitterionic organosilane assembly, enabling resisting surface reconstruction by forming a cross-linked network and polar segregation. Surface elemental composition was confirmed by X-ray photoelectron spectroscopy (XPS), and the long-term stability of modification was accessed using a contact angle goniometer. The biofouling tests were carried out by exposing substrates to bacterial, protein, and lipid solutions, revealing the excellent bioinertness of SBSi-tailored PDMS, even after 30 day storage in ambient. For the real-world application, we modified commercially available silicone hydrogel contact lenses with developed zwitterionic silane, presenting its antibacterial adhesion property. Moreover, the cytotoxicity of SBSi was accessed with NIH-3T3 fibroblast by the MTT assay, showing negligible cytotoxicity up to a concentration of 5 mM. Consequently, the strategy of surface engineering in this work can effectively retard the "hydrophobic recovery" occurrence and can be applied to other silicone-based medical devices in a facile way.

Types of indwelling urethral catheters for short-term catheterisation in hospitalised adults

BACKGROUND

Urinary tract infection (UTI) is the most common hospital-acquired infection. The major associated cause is indwelling urethral catheters. Several measures have been introduced to reduce catheter-associated urinary tract infections (CAUTIs). One of these measures is the introduction of specialised urethral catheters that have been designed to reduce the risk of infection. These include antiseptic-coated and antimicrobial-impregnated catheters.

OBJECTIVES

The primary objective of this review was to compare the effectiveness of different types of indwelling urethral catheters in reducing the risk of UTI and to assess their impact on other outcomes in adults who require short-term urethral catheterisation in hospitals.

SEARCH METHODS

We searched the Cochrane Incontinence Group's Specialised Trials Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE in process, ClinicalTrials.gov, WHO ICTRP and handsearching of journals and conference proceedings (searched 9 September 2014). We also examined the bibliographies of relevant articles and contacted catheter manufacturer representatives for trials.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) and quasi-RCTs comparing types of indwelling urethral catheters for short-term catheterisation in hospitalised adults. 'Short-term' is defined as a duration of catheterisation which is intended to be less than or equal to 14 days.

DATA COLLECTION AND ANALYSIS

At least two review authors independently screened abstracts, extracted data and assessed risk of bias of the included trials. Any disagreement was resolved by discussion or consultation with a third party. We processed data as described in the Cochrane Handbook for Systematic Reviews of Interventions. We assessed the quality of evidence using the GRADE approach.

MAIN RESULTS

Twenty-six trials met the inclusion criteria involving 12,422 hospitalised adults in 25 parallel group trials, and 27,878 adults in one large cluster-randomised cross-over trial. No trials compared one antiseptic catheter versus another, nor an antimicrobial catheter versus another. Antiseptic-coated indwelling urethral catheters versus standard indwelling urethral cathetersThe primary outcome, symptomatic CAUTI was reported in one large trial with a low risk of bias, comparing silver alloy hydrogel-coated latex catheter (antiseptic-coated) against a standard polytetrafluoroethylene (PTFE)-coated latex catheter (control). The trial used a pragmatic, US Centers for Disease Control and Prevention (CDC)-based definition for symptomatic CAUTI. For the comparison between silver alloy-coated catheter versus standard catheter, there was no significant difference in symptomatic CAUTI incidence (RR 0.99, 95% CI 0.85 to 1.16).For secondary outcomes, the included trials reported on two types of antiseptic catheters (coated with either silver oxide or silver alloy). For the outcome of bacteriuria, silver oxide catheters were not associated with any statistically significant reduction (RR 0.90, 95% CI 0.72 to 1.13). These catheters are no longer manufactured. Silver alloy catheters achieved a slight but statistically significant reduction in bacteriuria (RR 0.82, 95% CI 0.73 to 0.92). However, the one large trial with a low risk of bias did not support this finding (RR 0.99, 95% CI 0.85 to 1.16). The randomised cross-over trial of silver alloy catheters versus standard catheters was excluded from the pooled results because data were not available prior to crossover. The results of this trial showed less bacteriuria in the silver alloy catheter group.For the outcome of discomfort whilst the catheter was in-situ, fewer patients with silver alloy catheters complained of discomfort compared with standard catheters (RR 0.84, 95% CI 0.74 to 0.96). Antimicrobial-impregnated indwelling urethral catheters versus standard indwelling urethral cathetersThe primary outcome measure, symptomatic CAUTI was reported in one large trial with a low risk of bias, comparing nitrofurazone-impregnated silicone catheter (antimicrobial-impregnated) against a standard PTFE-coated latex catheter (control). The nitrofurazone catheter achieved a reduction in symptomatic CAUTI incidence which was of borderline statistical significance (RR 0.84, 95% CI 0.71 to 0.99).For secondary outcomes, the included trials reported on two types of antimicrobial catheters (impregnated with either nitrofurazone or minocycline/rifampicin). Antimicrobial-impregnated catheters, compared with standard catheters, were found to lower the rate of bacteriuria in the antimicrobial group for both minocycline and rifampicin (RR 0.36, 95% CI 0.18 to 0.73), and nitrofurazone (RR 0.73, 95% CI 0.64 to 0.85). The minocycline and rifampicin catheter is no longer manufactured.For the outcome of discomfort whilst the catheter was in-situ, more patients with nitrofurazone catheters complained of pain whilst the catheter was in-situ compared with standard catheters (RR 1.26, 95% CI 1.12 to 1.41). For the period after catheter removal, more patients with nitrofurazone catheters complained of pain than standard catheters (RR 1.43, 95% CI 1.30 to 1.57). Antimicrobial-impregnated indwelling urethral catheters versus antiseptic-coated indwelling urethral cathetersOne large trial compared antimicrobial-impregnated (nitrofurazone) catheters versus silver alloy-coated (antiseptic-coated) catheters. The results showed people were less likely to have a symptomatic CAUTI with nitrofurazone-impregnated catheters (228/2153, 10.6%) compared with silver alloy-coated catheters (263/2097, 12.5%), but this was of borderline statistical significance (RR 0.84, 95% CI 0.71 to 1.00). They did, however, have significantly less bacteriuria (RR 0.78, 95% CI 0.67 to 0.91),While the catheter was in-situ (RR 1.50, 95% CI 1.32 to 1.70), and on removal (RR 1.32, 95% CI 1.20 to 1.45), nitrofurazone catheters were associated with more discomfort compared with silver-coated catheters. One type of standard indwelling urethral catheter versus another type of standard indwelling urethral catheterNone of the trials comparing standard catheters versus other types of standard catheters measured symptomatic CAUTI. In terms of reducing bacteriuria, individual trials were too small to show whether one type of standard catheter was superior to another type. For the outcome of urethral reactions, fully siliconised catheters appeared to be superior to latex-based catheters. However, the trials involved small numbers of participants. There were no statistically significant differences between the different catheters for all other outcomes.

AUTHORS' CONCLUSIONS

Silver alloy-coated catheters were not associated with a statistically significant reduction in symptomatic CAUTI, and are considerably more expensive. Nitrofurazone-impregnated catheters reduced the risk of symptomatic CAUTI and bacteriuria, although the magnitude of reduction was low and hence may not be clinically important. However, they are more expensive than standard catheters. They are also more likely to cause discomfort than standard catheters.

Strategies to Prevent Catheter-Associated Urinary Tract Infections in Acute Care Hospitals: 2014 Update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their catheter-associated urinary tract infection (CAUTI) prevention efforts. This document updates “Strategies to Prevent Catheter-Associated Urinary Tract Infections in Acute Care Hospitals,” published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

Multicenter cohort study to assess the impact of a silver-alloy and hydrogel-coated urinary catheter on symptomatic catheter-associated urinary tract infections

PURPOSE

The purpose of this study was to determine the effect of a silver-alloy hydrogel catheter on symptomatic catheter-associated urinary tract infections (CAUTIs).

DESIGN

Multicenter before-after non-randomized cohort study.

SUBJECTS AND SETTING

Seven acute care hospitals ranging in size from 124 to 607 beds participated in this study. The study population included adult patients with a positive urine culture 2 or more days after admission, who underwent Foley catheterization.

METHODS

Catheter-associated urinary tract infection surveillance was conducted at each hospital for at least 3 months during the use of a standard catheter and 3 months during the use of the silver-alloy hydrogel catheter. Both the National Healthcare Safety Network (NHSN) surveillance and a clinical definition of CAUTI were used for rate calculation.

RESULTS

A 47% relative reduction in the CAUTI rate was observed with the silver-alloy hydrogel catheter compared to the standard catheter when both infection definitions were used (0.945/1000 patient days vs 0.498/1000 patient days) (odds ratio = 0.53; P < .0001; 95% CI: 0.45-0.62). When only NHSN-defined CAUTIs were considered, a 58% relative reduction occurred in the silver-alloy hydrogel period (0.60/1000 patient days vs 0.25/1000 patient days) (odds ratio = 0.42; P < .0001; 95% CI: 0.34-0.53). Antimicrobial days for CAUTIs decreased from 1165 (standard catheter period) to 406 (silver-alloy hydrogel period).

CONCLUSIONS

Use of a silver-alloy hydrogel urinary catheter reduced symptomatic CAUTI occurrences as defined by both NHSN and clinical criteria.

Catheter associated urinary tract infections

Urinary tract infection attributed to the use of an indwelling urinary catheter is one of the most common infections acquired by patients in health care facilities. As biofilm ultimately develops on all of these devices, the major determinant for development of bacteriuria is duration of catheterization. While the proportion of bacteriuric subjects who develop symptomatic infection is low, the high frequency of use of indwelling urinary catheters means there is a substantial burden attributable to these infections. Catheter-acquired urinary infection is the source for about 20% of episodes of health-care acquired bacteremia in acute care facilities, and over 50% in long term care facilities. The most important interventions to prevent bacteriuria and infection are to limit indwelling catheter use and, when catheter use is necessary, to discontinue the catheter as soon as clinically feasible. Infection control programs in health care facilities must implement and monitor strategies to limit catheter-acquired urinary infection, including surveillance of catheter use, appropriateness of catheter indications, and complications. Ultimately, prevention of these infections will require technical advances in catheter materials which prevent biofilm formation.

Eco-friendly synthesis of silver and gold nanoparticles with enhanced bactericidal activity and study of silver catalyzed reduction of 4-nitrophenol

The present study reports a simple and robust method for synthesis of silver and gold nanoparticles using Coleus forskohlii root extract as reducing and stabilizing agent. Stable silver nanoparticles (AgNPs) and gold nanopoarticles (AuNPs) were formed on treatment of an aqueous silver nitrate (AgNO3) and chloroauric acid (HAuCl4) solutions with the root extract. The nanoparticles obtained were characterized by UV-Visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). UV-Vis and TEM analysis indicate that with higher quantities of root extract, the interaction is enhanced leading to size reduction of spherical metal nanoparticles. XRD confirms face-centered cubic phase and the diffraction peaks can be attributed to (111), (200), (222) and (311) planes for these nanoparticles. These synthesized Ag and Au nanoparticles were found to exhibit excellent bactericidal activity against clinically isolated selected pathogens such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The synthesized AgNPs were also found to function as an efficient green catalyst in the reduction of anthropogenic pollutant 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride, which was apparent from the periodical color change from bright yellow to colorless, after the addition of AgNPs.

Antimicrobial megaprostheses supported with iodine

Deep infection associated with implants remains a serious complication of orthopedic surgery. We developed iodine coating for titanium implants. In this study, we performed a clinical trial of iodine-coated megaprostheses to evaluate its safety and antibacterial effects. Forty-seven patients with malignant bone tumor or pyogenic arthritis were treated using iodine-supported titanium megaprostheses between July 2008 and May 2013. The mean age was 53.6 years (range, 15-85 years). Twenty-six patients were males and 21 were females. The diagnoses included malignant bone tumor in 29 cases, infected total knee arthroplasty in 11 cases, chronic osteomyelitis due to pyogenic arthritis in six cases and loosening of total knee arthroplasty in one case. The iodine-supported implants used were 42 Kyocera Limb Salvage System and five KOBELCO K-MAX K-3. These megaprostheses were used to prevent infection in 21 patients, treat active infections in 26 patients. The mean follow-up period was 30.1 months (range, 8-50). Infection was prevented in 20 out of 21 patients. Only one patient had surgical site infection caused by Pseudomonas aeruginosa and was cured by intravenous administration of antibiotics alone without removal of the implant. In 26 treatment cases involving one- or two-stage revision surgery, infection subsided without any additional surgery. In all cases, there were no signs of infection at the time of the last follow-up. White blood cell and C-reactive protein levels returned to normal within four weeks after surgery. To confirm systemic effects of iodine, thyroid hormone levels in the blood were examined. Abnormalities of thyroid gland function were not detected. Loosening of the implants was not observed. Excellent bone ingrowth and ongrowth were found around iodine-supported megaprostheses. The iodine-supported titanium megaprostheses are highly effective and show promise for the prevention and treatment of infections in large bone defects. No cytotoxicity or adverse effects were detected with this treatment.

epic3: national evidence-based guidelines for preventing healthcare-associated infections in NHS hospitals in England

National evidence-based guidelines for preventing healthcare-associated infections (HCAI) in National Health Service (NHS) hospitals in England were originally commissioned by the Department of Health and developed during 1998-2000 by a nurse-led multi-professional team of researchers and specialist clinicians. Following extensive consultation, they were first published in January 2001(1) and updated in 2007.(2) A cardinal feature of evidence-based guidelines is that they are subject to timely review in order that new research evidence and technological advances can be identified, appraised and, if shown to be effective for the prevention of HCAI, incorporated into amended guidelines. Periodically updating the evidence base and guideline recommendations is essential in order to maintain their validity and authority. The Department of Health commissioned a review of new evidence and we have updated the evidence base for making infection prevention and control recommendations. A critical assessment of the updated evidence indicated that the epic2 guidelines published in 2007 remain robust, relevant and appropriate, but some guideline recommendations required adjustments to enhance clarity and a number of new recommendations were required. These have been clearly identified in the text. In addition, the synopses of evidence underpinning the guideline recommendations have been updated. These guidelines (epic3) provide comprehensive recommendations for preventing HCAI in hospital and other acute care settings based on the best currently available evidence. National evidence-based guidelines are broad principles of best practice that need to be integrated into local practice guidelines and audited to reduce variation in practice and maintain patient safety. Clinically effective infection prevention and control practice is an essential feature of patient protection. By incorporating these guidelines into routine daily clinical practice, patient safety can be enhanced and the risk of patients acquiring an infection during episodes of health care in NHS hospitals in England can be minimised.

Nanomaterials and synergistic low-intensity direct current (LIDC) stimulation technology for orthopedic implantable medical devices

Nanomaterials play a significant role in biomedical research and applications because of their unique biological, mechanical, and electrical properties. In recent years, they have been utilized to improve the functionality and reliability of a wide range of implantable medical devices ranging from well-established orthopedic residual hardware devices (e.g., hip implants) that can repair defects in skeletal systems to emerging tissue engineering scaffolds that can repair or replace organ functions. This review summarizes the applications and efficacies of these nanomaterials that include synthetic or naturally occurring metals, polymers, ceramics, and composites in orthopedic implants, the largest market segment of implantable medical devices. The importance of synergistic engineering techniques that can augment or enhance the performance of nanomaterial applications in orthopedic implants is also discussed, the focus being on a low-intensity direct electric current (LIDC) stimulation technology to promote the long-term antibacterial efficacy of oligodynamic metal-based surfaces by ionization, while potentially accelerating tissue growth and osseointegration. While many nanomaterials have clearly demonstrated their ability to provide more effective implantable medical surfaces, further decisive investigations are necessary before they can translate into medically safe and commercially viable clinical applications. The article concludes with a discussion about some of the critical impending issues with the application of nanomaterials-based technologies in implantable medical devices, and potential directions to address these.

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.

Use of silver in the prevention and treatment of infections: silver review

BACKGROUND

The use of silver for the treatment of various maladies or to prevent the transmission of infection dates back to at least 4000 b.c.e. Medical applications are documented in the literature throughout the 17th and 18th centuries. The bactericidal activity of silver is well established. Silver nitrate was used topically throughout the 1800 s for the treatment of burns, ulcerations, and infected wounds, and although its use declined after World War II and the advent of antibiotics, Fox revitalized its use in the form of silver sulfadiazine in 1968.

METHOD

Review of the pertinent English-language literature.

RESULTS

Since Fox's work, the use of topical silver to reduce bacterial burden and promote healing has been investigated in the setting of chronic wounds and ulcers, post-operative incision dressings, blood and urinary catheter designs, endotracheal tubes, orthopedic devices, vascular prostheses, and the sewing ring of prosthetic heart valves. The beneficial effects of silver in reducing or preventing infection have been seen in the topical treatment of burns and chronic wounds and in its use as a coating for many medical devices. However, silver has been unsuccessful in certain applications, such as the Silzone heart valve. In other settings, such as orthopedic hardware coatings, its benefit remains unproved.

CONCLUSION

Silver remains a reasonable addition to the armamentarium against infection and has relatively few side effects. However, one should weigh the benefits of silver-containing products against the known side effects and the other options available for the intended purpose when selecting the most appropriate therapy.

Types of indwelling urinary catheters for long-term bladder drainage in adults

BACKGROUND

Prolonged urinary catheterization is common amongst people in long-term care settings and this carries a high risk of developing a catheter-related urinary tract infection and associated complications. A variety of different kinds of urethral catheters are available. Some have been developed specifically to lower the risk of catheter-associated infection, for example antiseptic or antibiotic impregnated catheters. Ease of use, comfort and handling for the caregivers and patients, and cost-effectiveness are also important factors influencing choice.

OBJECTIVES

The primary objective was to determine which type of indwelling urinary catheter is best to use for long-term bladder drainage in adults.

SEARCH METHODS

We searched the Cochrane Incontinence Group Specialised Register (last searched 31 March 2011), which includes searches of CENTRAL, MEDLINE and handsearching of journals and conference proceedings, and the reference lists of relevant articles.

SELECTION CRITERIA

All randomised trials comparing types of indwelling urinary catheters for long-term catheterization in adults. Long-term catheterization was defined as more than 30 days.

DATA COLLECTION AND ANALYSIS

Data extraction has been undertaken by two review authors working independently and simultaneously. Any disagreement has been resolved by a third review author. The included trial data were handled according to the methods of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Three trials were included, involving 102 adults in various settings. Two trials had a parallel group design and one was a randomised cross-over trial.Only two of the six targeted comparisons were assessed by these trials: antiseptic impregnated catheters versus standard catheters (one trial) and one type of standard catheter versus another standard catheter (two trials).The single small cross-over trial was inadequate to assess the value of silver alloy (antiseptic) impregnated catheters. In the two trials comparing different types of standard catheters, estimates of differences were all imprecise because the trials also had small sample sizes; confidence intervals (CI) were too wide to rule out clinically important differences. One trial did suggest, however, that the use of a hydrogel coated latex catheter rather than a silicone catheter may be better tolerated (risk ratio (RR) for need for early removal 0.41, 95% CI 0.22 to 0.77).

AUTHORS' CONCLUSIONS

The updated search could not reveal any additional evidence. Very few trials have compared different types of catheter for long-term bladder drainage. All trials were small and showed methodological weaknesses. Therefore, the evidence was not sufficient as a reliable basis for practical conclusions. Further, better quality trials are needed to address the current lack of evidence in this clinically important area.

Thromboresistance characterization of extruded nitric oxide-releasing silicone catheters

Intravascular catheters used in clinical practice can activate platelets, leading to thrombus formation and stagnation of blood flow. Nitric oxide (NO)-releasing polymers have been shown previously to reduce clot formation on a number of blood contacting devices. In this work, trilaminar NO-releasing silicone catheters were fabricated and tested for their thrombogenicity. All catheters had specifications of L = 6 cm, inner diameter = 21 gauge (0.0723 cm), outer diameter = 12 gauge (0.2052 cm), and NO-releasing layer thickness = 200 ± 11 µm. Control and NO-releasing catheters were characterized in vitro for their NO flux and NO release duration by gas phase chemiluminescence measurements. The catheters were then implanted in the right and left internal jugular veins of (N = 6 and average weight = 3 kg) adult male rabbits for 4 hours thrombogenicity testing. Platelet counts and function, methemoglobin (metHb), hemoglobin (Hb), and white cell counts and functional time (defined as patency time of catheter) were monitored as measured outcomes. Nitric oxide-releasing catheters (N = 6) maintained an average flux above (2 ± 0.5) × 10(-10) mol/min/cm for more than 24 hours, whereas controls showed no NO release. Methemoglobin, Hb, white cell, and platelet counts and platelet function at 4 hours were not significantly different from baseline (α = 0.05). However, clots on controls were visibly larger and prevented blood draws at a significantly (p < 0.05) earlier time (2.3 ± 0.7 hours) into the experiment, whereas all NO-releasing catheters survived the entire 4 hours test period. Results indicate that catheter NO flux levels attenuated thrombus formation in a short-term animal model.

Innovative antimicrobial coating of titanium implants with iodine

BACKGROUND

Postoperative infection associated with implants remains a serious complication in orthopedic surgery. Several biomaterial surface treatments have been proposed as a means of reducing the incidence of implant-associated infections. In this study, a clinical trial was performed using an iodine-supported titanium that suppresses the microbial activities.

METHODS

A total of 222 patients with postoperative infection or compromised status were treated using iodine-supported titanium implants. The mean age of the patients was 49.4 years (range 5-85 years). One hundred twenty-seven patients were male and 95 were female. In 158 patients, iodine-supported implants were used to prevent infection, such as compromised hosts and conditions, and in 64 patients to treat active infection. White blood cell (WBCs) and C-reactive protein (CRP) levels were measured pre- and postoperatively in all patients. To confirm whether iodine from the implant affected physiological functions, thyroid hormone levels in the blood were examined. Both examinations were conducted sequentially for a year. Radiological evaluations were performed regularly after the operation. The chronological changes of the iodine amount were evaluated using half pins removed after completion of external fixation.

RESULTS

The mean follow-up period was 18.4 months (range 3-44 months). Acute infection developed in three tumor cases among the 158 patients on preventive therapy. All three recovered without removal of the implants. Infection was cured in all 64 patients with infection. Median WBC levels were in the normal range, and median CRP levels returned to <0.5 within 4 weeks after surgery. Abnormalities of thyroid gland function were not detected. None of the patients experienced loosening of the implants. There were two patients with mechanical implant failure, which was treated by re-implantation. Excellent bone ingrowth and ongrowth were found around all hip and tumor prostheses. One year later, the amount of iodine on external fixation pins remained about 20-30%.

CONCLUSIONS

Iodine-supported titanium implants can be very effective for preventing and treating infections after orthopedic surgery. Cytotoxicity and adverse effects were not detected.

The Use of Antimicrobial Nanoparticles to Control Oral Infections

The potential of antimicrobial nanoparticles to control oral infections is reviewed. Such particles can be classified as having a size no greater than 100 nm and are produced using traditional or more novel techniques. Exploitation of the toxic properties of nanoparticles to bacteria, fungi and viruses, in particular metals and metal oxides, and their incorporation into polymeric materials have increased markedly over the past decade. The potential of nanoparticles to control the formation of biofilms within the oral cavity, as a function of their biocidal, anti-adhesive and delivery capabilities, is now receiving close attention. The latest insights into the application of nanoparticles within this field, including their use in photodynamic therapy, will be discussed. Possible approaches to alter biocompatibility and desired function will also be covered.

Antimicrobial acrylic materials with in situ generated silver nanoparticles

Polymethyl methacrylate (PMMA) is widely used to treat traumatic head injuries (cranioplasty) and orthopedic injuries (bone cement), but there is a problem with implant-centered infections. With organisms such as Acinetobacter baumannii and methicillin-resistant staphylococcus aureus developing resistance to antibiotics, there is a need for novel antimicrobial delivery mechanisms without risk of developing resistant organisms.

OBJECTIVES

To develop a novel antimicrobial implant material by generating silver nanoparticles (AgNP) in situ in PMMA.

RESULTS

All PMMA samples with AgNP's (AgNP-PMMA) released Ag(+) ions in vitro for over 28 days. In vitro antimicrobial assays revealed that these samples (even samples with the slowest release rate) inhibited 99.9% of bacteria against four different strains of bacteria. Long-term antimicrobial assay showed a continued antibacterial effect past 28 days. Some AgNP-loaded PMMA groups had comparable Durometer-D hardness (a measure of degree of cure) and modulus to control PMMA, but all experimental groups had slightly lower ultimate transverse strengths.

CONCLUSIONS

AgNP-PMMA demonstrated a tremendously broad-spectrum and long-intermediate-term antimicrobial effect with comparable mechanical properties to control PMMA. Current efforts are focused on further improving mechanical properties by reducing AgNP loading and assessing fatigue properties.

Silver polymeric nanocomposites as advanced antimicrobial agents: classification, synthetic paths, applications, and perspectives

Utilization of metallic nanoparticles in various biotechnological and medical applications represents one of the most extensively investigated areas of the current materials science. These advanced applications require the appropriate chemical functionalization of the nanoparticles with organic molecules or their incorporation in suitable polymer matrices. The intensified interest in polymer nanocomposites with silver nanoparticles is due to the high antimicrobial effect of nanosilver as well as the unique characteristics of polymers which include their excellent structural uniformity, multivalency, high degree of branching, miscellaneous morphologies and architectures, and highly variable chemical composition. In this review, we explore several aspects of antimicrobial polymer silver nanocomposites, giving special focus to the critical analysis of the reported synthetic routes including their advantages, drawbacks, possible improvements, and real applicability in antibacterial and antifungal therapy. A special attention is given to "green" synthetic routes exploiting the biopolymeric matrix and to the methods allowing preparing magnetically controllable antimicrobial polymers for targeting to an active place. The controversial mechanism of the action of silver against bacteria, fungi and yeasts as well as perspectives and new applications of silver polymeric nanocomposites is also briefly discussed.

Complicated urinary tract infection in adults

BACKGROUND

Complicated urinary tract infection occurs in individuals with functional or structural abnormalities of the genitourinary tract.

OBJECTIVE

To review current knowledge relevant to complicated urinary tract infection, and to provide evidence-based recommendations for management.

METHODS

The literature was reviewed through a PubMed search, and additional articles were identified by journal reference review. A draft guideline was prepared and critically reviewed by members of the Association of Medical Microbiology and Infectious Disease Canada Guidelines Committee, with modifications incorporated following the review.

RESULTS

Many urological abnormalities may be associated with complicated urinary infection. There is a wide spectrum of potential infecting organisms, and isolated bacteria tend to be more resistant to antimicrobial therapy. Morbidity and infection outcomes in subjects with complicated urinary infection are principally determined by the underlying abnormality rather than the infection. Principles of management include uniform collection of a urine specimen for culture before antimicrobial therapy, characterization of the underlying genitourinary abnormality, and nontreatment of asymptomatic bacteriuria except before an invasive genitourinary procedure. The antimicrobial regimen is determined by clinical presentation, patient tolerance, renal function and known or anticipated infecting organisms. If the underlying abnormality contributing to the urinary infection cannot be corrected, then early post-treatment recurrence of infection is anticipated.

CONCLUSIONS

The management of complicated urinary infection is individualized depending on patient variables and the infecting organism. Further clinical investigations are necessary to assist in determining optimal antimicrobial regimens.

The efficacy of a novel antibacterial hydroxyapatite nanoparticle-coated indwelling urinary catheter in preventing biofilm formation and catheter-associated urinary tract infection in rabbits

The aim of this study was to investigate of the efficacy and reliability of a novel antimicrobial hydroxyapatite (HA) nanoparticle coating of urethral catheters, in the prophylaxis of biofilm formation and bacteriuria in rabbits. A total of 60 male rabbits were randomized to the control and study groups and each group was divided into three subgroups depending on 3, 5 and 7 days of the urethral catheterization period. The rabbits in the study group were catheterized with Ag(+)-incorporated nano-HA coated urethral catheters and those in the control group with standard silicon-latex urethral catheters. Urine and catheter surface smear samples were conducted for bacteriological analysis. Catheter cross-section samples were undergone measuring of biofilm thickness. Tissue samples of bladder and urethra were inspected for histological changes. The results indicate that at the end of 7 days of the catheterization period, the number of the rabbits with bacteriuria was significantly lower in the study group versus control group (p (¶) = 0.020). The biofilm formation on luminal surface of the catheters was significantly thinner in the study group versus control group, at the end of 5 and 7 days of the catheterization period (0.035 and 0.035, respectively).No histological adverse change or particle penetration was detected in the urothelium. In conclusion, it was observed that Ag(+) + HA nanoparticle coating significantly lowered the incidence of catheter-related bacteriuria and decreased biofilm formation, at the end of 7 days study period. The novel antimicrobial urethral catheter coating appeared to have a potential in the prophylaxis of catheter-induced urinary tract infections.

Impact of silver-containing wound dressings on bacterial biofilm viability and susceptibility to antibiotics during prolonged treatment

The long-term antimicrobial efficacy of silver dressings against bacterial biofilms was investigated in a 7-day treatment in vitro model where the protein-rich medium was refreshed daily in order to mimic the conditions found in a wound bed. The use of plate-to-plate transfer assays demonstrated measurable differences in the effectiveness of several silver dressings on the viability of biofilm bacteria and their susceptibility to antibiotics. Whereas after the first day of treatment, all dressings used resulted in a significant reduction in the number of viable cells in the biofilms and disruption of the biofilm colonies, during prolonged treatment, the efficacy of dressings with hydrophilic base materials diminished with daily transfers, and bacterial populations recovered. For dressings with hydrophobic base materials, the level of efficacy correlated with the silver species loaded. Biofilm bacteria, which survived the initial silver treatment, were susceptible to tobramycin, ciprofloxacin, and trimethoprim-sulfamethoxazole, in contrast to untreated biofilms, which were highly tolerant to the same antibiotics. This acquired susceptibility was unaffected by the longevity of pretreatment with the silver dressings but depended on the dressing used. The antimicrobial efficacy of the dressings correlated with the type of the dressing base material and silver species loaded.

Reduction of periprosthetic infection with silver-coated megaprostheses in patients with bone sarcoma

BACKGROUND AND OBJECTIVES

The placement of megaprostheses in patients with bone sarcoma is associated with high rates of infection, despite prophylactic antibiotic administration. In individual cases, secondary amputation is unavoidable in the effort to cure infection.

METHODS

The infection rate in 51 patients with sarcoma (proximal femur, n = 22; proximal tibia, n = 29) who underwent placement of a silver-coated megaprosthesis was assessed prospectively over a 5-year period, along with the treatment administered for infection. The infection rate was compared with the data for 74 patients in whom an uncoated titanium megaprosthesis (proximal femur, n = 33; proximal tibia, n = 41) was implanted.

RESULTS

The infection rate was substantially reduced from 17.6% in the titanium to 5.9% in the silver group. Whereas 38.5% of patients in the titanium group ultimately had to undergo amputation when periprosthetic infection developed, these mutilating surgical procedures were not necessary in the study group.

CONCLUSIONS

The use of silver-coated prostheses reduced the infection rate in the medium term. In addition, less aggressive treatment of infection was possible in the group with silver-coated prostheses. Further studies with longer term follow-up periods and larger numbers of patients are warranted in order to confirm these encouraging results.

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.

Staphylococcus epidermidis device-related infections: pathogenesis and clinical management

Staphylococcus epidermidis, the most frequently isolated coagulase-negative staphylococcus, is the leading cause of infection related to implanted medical devices (IMDs). This is directly related to its capability to establish multilayered, highly structured biofilms on artificial surfaces. At present, conventional systemic therapies using standard antimicrobial agents represent the main strategy to treat and prevent medical device-associated infections. However, device-related infections are notoriously difficult to treat and bacteria within biofilm communities on the surface of IMDs frequently outlive treatment, and removal of the medical device is often required for successful therapy. Importantly, major advances in this research area have been made, leading to a greater understanding of the complexities of biofilm formation of S. epidermidis and resulting in significant developments in the treatment and prevention of infections related to this member of the coagulase-negative group of staphylococci. This review will examine the pathogenesis of the clinically significant S. epidermidis and provide an overview of the conventional and emerging antibiofilm approaches in the management of medical device-associated infections related to this important nosocomial pathogen.

Novel antiseptic urinary catheters for prevention of urinary tract infections: correlation of in vivo and in vitro test results

Urinary catheters are widely used for hospitalized patients and are often associated with high rates of urinary tract infection. We evaluated in vitro the antiadherence activity of a novel antiseptic Gendine-coated urinary catheter against several multidrug-resistant bacteria. Gendine-coated urinary catheters were compared to silver hydrogel-coated Foley catheters and uncoated catheters. Bacterial biofilm formation was assessed by quantitative culture and scanning electron microscopy. These data were further correlated to an in vivo rabbit model. We challenged 31 rabbits daily for 4 days by inoculating the urethral meatus with 1.0 x 10(9) CFU streptomycin-resistant Escherichia coli per day. In vitro, Gendine-coated urinary catheters reduced the CFU of all organisms tested for biofilm adherence compared with uncoated and silver hydrogel-coated catheters (P < 0.004). Scanning electron microscopy analysis showed that a thick biofilm overlaid the control catheter and the silver hydrogel-coated catheters but not the Gendine-coated urinary catheter. Similar results were found with the rabbit model. Bacteriuria was present in 60% of rabbits with uncoated catheters and 71% of those with silver hydrogel-coated catheters (P < 0.01) but not in those with Gendine-coated urinary catheters. No rabbits with Gendine-coated urinary catheters had invasive bladder infections. Histopathologic assessment revealed no differences in toxicity or staining. Gendine-coated urinary catheters were more efficacious in preventing catheter-associated colonization and urinary tract infections than were silver hydrogel-coated Foley catheters and uncoated catheters.

The role of surfaces in catheter-associated infections

In this critical review the biocidal efficacies of a variety of antimicrobial coatings currently in use for catheter surfaces are discussed to formulate the best strategy for decreasing the risk of catheter-associated infections. The development of new coatings containing antimicrobial chemicals and light-activated antimicrobial agents, and their applicability for use in catheters are summarised (132 references).

Advances in microbial biofilm prevention on indwelling medical devices with emphasis on usage of acoustic energy

Microbial biofilms are a major impediment to the use of indwelling medical devices, generating device-related infections with high morbidity and mortality. Major efforts directed towards preventing and eradicating the biofilm problem face difficulties because biofilms protect themselves very effectively by producing a polysaccharide coating, reducing biofilm sensitivity to antimicrobial agents. Techniques applied to combating biofilms have been primarily chemical. These have met with partial and limited success rates, leading to current trends of eradicating biofilms through physico-mechanical strategies. Here we review the different approaches that have been developed to control biofilm formation and removal, focusing on the utilization of acoustic energy to achieve these objectives.

The value of infectious diseases specialists: non-patient care activities

Recent developments in health care have focused efforts on both the national and local levels to reduce unnecessary health care costs and the number of hospital stays while increasing the quality of care, particularly in the context of hospital-associated infections. Infectious diseases specialists who contract to oversee infection-control and antibiotic-stewardship programs are uniquely positioned to play a pivotal role in helping hospitals to prosper in this new environment. This article will detail the available data supporting the value of infectious diseases specialists in their roles of directing antimicrobial-management and infection-control programs, maintaining health care workers' well-being, and minimizing exposure. The evidence in support of the influence of infectious diseases specialists to achieve cost-savings, decrease the length of hospital stays, and improve outcomes is robust and can be used as the framework for negotiating appropriate compensation from hospital management for these activities. Presenting this information in an amicable but definitive framework may be the linchpin to the overall success of the movement to improve quality of care while minimizing hospital costs and antimicrobial use. Developing this ability is critical to infectious diseases specialists' success as they redefine their role in the quality-of-care and risk-management arenas.

Silver nanoparticles as a new generation of antimicrobials

Silver has been in use since time immemorial in the form of metallic silver, silver nitrate, silver sulfadiazine for the treatment of burns, wounds and several bacterial infections. But due to the emergence of several antibiotics the use of these silver compounds has been declined remarkably. Nanotechnology is gaining tremendous impetus in the present century due to its capability of modulating metals into their nanosize, which drastically changes the chemical, physical and optical properties of metals. Metallic silver in the form of silver nanoparticles has made a remarkable comeback as a potential antimicrobial agent. The use of silver nanoparticles is also important, as several pathogenic bacteria have developed resistance against various antibiotics. Hence, silver nanoparticles have emerged up with diverse medical applications ranging from silver based dressings, silver coated medicinal devices, such as nanogels, nanolotions, etc.

Heparin coating on ureteral Double J stents prevents encrustations: an in vivo case study

PURPOSE

To evaluate the ability of heparin coating to inhibit Double J stent encrustation and compare it with the classic polyurethane Double J stent.

PATIENTS AND METHODS

The study involved five patients with bilateral obstructions, who required bilateral ureteral Double J stent placement. Every patient received a heparin-coated Double J stent and a traditional polyurethane Double J stent for 1 month. After removal, the stents were analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and micro-infrared spectrophotometry (Micro-IR). These same techniques were used to analyze the heparin-coated and uncoated stents before insertion. The thickness, extension, and composition of encrustation of the coated and uncoated stents were compared. Moreover, two heparin-coated stents were analyzed with the same techniques after they had been in place for 10 and 12 months.

RESULTS

FESEM analysis showed that the difference in encrustation thickness and extension between the two groups was significant. EDS and Micro-IR confirmed that in the heparinized stents the encrustations were not as uniform and compact as those in the uncoated stents. The stents that were left in place long-term were free of encrustations and had no changes in the heparin layer.

CONCLUSIONS

Heparin coating reduces stent encrustation. Moreover, as no changes were seen in the heparin layer, we concluded that covalent heparin bonding enhances its adhesion to the polyurethane surface and ensures its stability for long periods. The heparin-coated stent appears to be a useful tool for long-term urinary drainage.

Types of urethral catheters for management of short-term voiding problems in hospitalised adults

BACKGROUND

Urinary tract infection (UTI) is the most common hospital acquired infection. The major associated cause is indwelling urinary catheters. Currently there are many types of catheters available. A variety of specialised urethral catheters have been designed to reduce the risk of infection. These include antiseptic impregnated catheters and antibiotic impregnated catheters. Other issues that should be considered when choosing a catheter are ease of use, comfort and cost.

OBJECTIVES

The primary objective of this review was to determine the effect of type of indwelling urethral catheter on the risk of urinary tract infection in adults who undergo short-term urinary catheterisation.

SEARCH STRATEGY

We searched the Specialised Trials Register of the Cochrane Incontinence Group (searched 11 September 2007). We also examined the bibliographies of relevant articles and contacted catheter manufacturer representatives for trials.

SELECTION CRITERIA

All randomised and quasi randomised trials comparing types of indwelling urinary catheters for short-term catheterisation in hospitalised adults. Short-term catheterisation was defined as up to and including fourteen days, or other temporary short-term use as defined by the trialists (for example less than 21 days with data time points at 7 day intervals).

DATA COLLECTION AND ANALYSIS

Data were extracted by one reviewer and independently verified by a second reviewer. Disagreements were resolved by discussion. Data were processed as described in the Cochrane Handbook. Where data in trials were not fully reported, clarification was sought directly from the trialists (secondary sources were used to confirm results of one trial).

MAIN RESULTS

Twenty three trials met the inclusion criteria involving 5236 hospitalised adults in 22 parallel group trials and 27,878 adults in one large cluster-randomised cross-over trial. The antiseptic catheters were either impregnated with silver oxide or silver alloy. Silver oxide catheters were not associated with a statistically significant reduction in bacteriuria in short-term catheterised hospitalised adults but the confidence intervals were wide (RR 0.89, 95% CI 0.68 to 1.15) and these catheters are no longer available. Silver alloy catheters were found to significantly reduce the incidence of asymptomatic bacteriuria (RR 0.54, 95% CI 0.43 to 0.67) in hospitalised adults catheterised for less than one week. At greater than one week of catheterisation the risk of asymptomatic bacteriuria was still reduced with the use of silver alloy catheters (RR 0.64, 95% CI 0.51 to 0.80). The randomised cross-over trial of silver alloy catheters versus standard catheters was excluded from the pooled results because data were not available prior to crossover. The results of this trial indicated benefit from the silver alloy catheters and included an economic analysis that indicated cost savings of between 3.3 per cent and 35.5 per cent. Antibiotic impregnated catheters were compared to standard catheters and found to lower the rate of asymptomatic bacteriuria in the antibiotic group at less than one week of catheterisation for both minocycline and rifampicin (RR 0.36, 95% CI 0.18 to 0.73), and nitrofurazone (RR 0.52, 95% CI 0.34 to 0.78). However, at greater than one week the results were not statistically significant. One of 56 men in the antibiotic impregnated group had a symptomatic UTI compared with 6 of 68 who had standard catheters (RR 0.20, 95% CI 0.03 to 1.63). Three trials compared two different types of standard catheters (defined as catheters that are not impregnated with antiseptics or antibiotics) to investigate infection. Individual trials were too small to show whether or not one type of standard catheter reduced the risk of catheter related urinary tract infection compared to another type of standard catheter.

AUTHORS' CONCLUSIONS

The results suggest that the use of silver alloy indwelling catheters for catheterising hospitalised adults short-term reduces the risk of catheter acquired urinary tract infection. Further economic evaluation is required to confirm that the reduction of infection compensates for the increased cost of silver alloy catheters.Catheters impregnated with antibiotics are also beneficial in reducing bacteriuria in hospitalised adults catheterised for less than one week but the data were too few to draw conclusions about those catheterised for longer. There was not enough evidence to suggest whether or not any standard catheter was better than another in terms of reducing the risk of urinary tract infection in hospitalised adults catheterised short-term. Siliconised catheters may be less likely to cause urethral side effects in men; however, this result should be interpreted with some caution as the trials were small and the outcome definitions and specific catheters compared varied.

Complicated catheter-associated urinary tract infections due to Escherichia coli and Proteus mirabilis

Catheter-associated urinary tract infections (CAUTIs) represent the most common type of nosocomial infection and are a major health concern due to the complications and frequent recurrence. These infections are often caused by Escherichia coli and Proteus mirabilis. Gram-negative bacterial species that cause CAUTIs express a number of virulence factors associated with adhesion, motility, biofilm formation, immunoavoidance, and nutrient acquisition as well as factors that cause damage to the host. These infections can be reduced by limiting catheter usage and ensuring that health care professionals correctly use closed-system Foley catheters. A number of novel approaches such as condom and suprapubic catheters, intermittent catheterization, new surfaces, catheters with antimicrobial agents, and probiotics have thus far met with limited success. While the diagnosis of symptomatic versus asymptomatic CAUTIs may be a contentious issue, it is generally agreed that once a catheterized patient is believed to have a symptomatic urinary tract infection, the catheter is removed if possible due to the high rate of relapse. Research focusing on the pathogenesis of CAUTIs will lead to a better understanding of the disease process and will subsequently lead to the development of new diagnosis, prevention, and treatment options.

Types of indwelling urinary catheters for long-term bladder drainage in adults

BACKGROUND

Prolonged urinary catheterisation is common amongst people in long-term care settings and this carries a high risk of developing a catheter-related urinary tract infection and associated complications. A variety of different kinds of urethral catheters are available. Some have been developed specifically to lower the risk of catheter-associated infection, for example antiseptic or antibiotic impregnated catheters. Ease of use, comfort and handling for the caregivers and patients, and cost-effectiveness are also important factors influencing choice.

OBJECTIVES

The primary objective was to determine which type of in-dwelling urinary catheter is best to use for long-term bladder drainage in adults.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Trials Register (searched 15 December 2004), MEDLINE (January 1950 to February 2005) and CINAHL (January 1982 to February 2005). We also handsearched 28 relevant journals and conference proceedings. We examined the bibliographies of relevant articles and contacted catheter manufacturers, scientific societies and experts for trials.

SELECTION CRITERIA

All randomised trials comparing types of indwelling urinary catheters for long-term catheterisation in adults. Long-term catheterisation was defined as more than 30 days.

DATA COLLECTION AND ANALYSIS

Data extraction has been undertaken by two review authors independently and simultaneously. Any disagreement has been resolved by a third review author. The included trial data were handled according to the description of the Cochrane Collaboration Reviewers' Handbook.

MAIN RESULTS

Three trials were included involving 102 adults in various settings. Two trials had a parallel group design and one was a randomised cross-over trial. Only two of the six targeted comparisons were assessed by these trials: antiseptic impregnated catheters versus standard catheters (one trial) and one type of standard catheter versus another standard catheter (two trials). The single small cross-over trial was inadequate to assess the value of silver alloy (antiseptic) impregnated catheters. In the two trials comparing different types of standard catheters, estimates of differences were all imprecise because the trials also had small sample sizes: confidence intervals were too wide to rule out clinically important differences. One trial did suggest, however, that the use of a hydrogel coated latex catheter rather than a silicone catheter may be better tolerated (RR for need for early removal 0.41, 95% CI 0.22 to 0.77).

AUTHORS' CONCLUSIONS

Very few trials have compared types of catheter for long-term bladder drainage. All were small and showed methodically weaknesses. Therefore, the evidence was not sufficient as a reliable basis for practical conclusions. Further, better quality trials are needed to address the current lack of evidence in this clinically important area.

epic2: National evidence-based guidelines for preventing healthcare-associated infections in NHS hospitals in England

National evidence-based guidelines for preventing healthcare-associated infections (HCAI) in National Health Service (NHS) hospitals in England were commissioned by the Department of Health (DH) and developed during 1998-2000 by a nurse-led multi-professional team of researchers and specialist clinicians. Following extensive consultation, they were published in January 2001. These guidelines describe the precautions healthcare workers should take in three areas: standard principles for preventing HCAI, which include hospital environmental hygiene, hand hygiene, the use of personal protective equipment, and the safe use and disposal of sharps; preventing infections associated with the use of short-term indwelling urethral catheters; and preventing infections associated with central venous catheters. The evidence for these guidelines was identified by multiple systematic reviews of experimental and non-experimental research and expert opinion as reflected in systematically identified professional, national and international guidelines, which were formally assessed by a validated appraisal process. In 2003, we developed complementary national guidelines for preventing HCAI in primary and community care on behalf of the National Collaborating Centre for Nursing and Supportive Care (National Institute for Healthand Clinical Excellence). A cardinal feature of evidence-based guidelines is that they are subject to timely review in order that new research evidence and technological advances can be identified, appraised and, if shown to be effective in preventing HCAI, incorporated into amended guidelines. Periodically updating the evidence base and guideline recommendations is essential in order to maintain their validity and authority. Consequently, the DH commissioned a review of new evidence published following the last systematic reviews. We have now updated the evidence base for making infection prevention and control recommendations. A critical assessment of the updated evidence indicated that the original epic guidelines published in 2001 remain robust, relevant and appropriate but that adjustments need to be made to some guideline recommendations following a synopsis of the evidence underpinning the guidelines. These updated national guidelines (epic2) provide comprehensive recommendations for preventing HCAI in hospitals and other acute care settings based on the best currently available evidence. Because this is not always the best possible evidence, we have included a suggested agenda for further research in each section of the guidelines. National evidence-based guidelines are broad principles of best practice which need to be integrated into local practice guidelines. To monitor implementation, we have suggested key audit criteria for each section of recommendations. Clinically effective infection prevention and control practice is an essential feature of protecting patients. By incorporating these guidelines into routine daily clinical practice, patient safety can be enhanced and the risk of patients acquiring an infection during episodes of healthcare in NHS hospitals in England can be minimised.