Are Antimicrobial-Impregnated Catheters Effective? When Does Repetition Reach the Point of Exhaustion?

Effectiveness of Minocycline and Rifampin vs Chlorhexidine and Silver Sulfadiazine-Impregnated Central Venous Catheters in Preventing Central Line-Associated Bloodstream Infection in a High-Volume Academic Intensive Care Unit: A Before and after Trial

BACKGROUND

Use of chlorhexidine and silver sulfadiazine-impregnated (CSS) central venous catheters (CVCs) has not been shown to decrease the catheter-related bloodstream infection rate in an ICU. The purpose of this study was to determine if use of minocycline and rifampin-impregnated (MR) CVCs would decrease central line-associated bloodstream infection (CLABSI) rates compared with those observed with use of CSS-impregnated CVCs.

STUDY DESIGN

A total of 7,181 patients were admitted to a 24-bed university hospital surgical ICU: 2,551 between March 2004 and August 2005 (period 1) and 4,630 between April 2006 and July 2008 (period 2). All patients requiring CVC placement in period 1 had a CSS catheter inserted, and in period 2 all patients had MR CVCs placed.

RESULTS

Twenty-two CLABSIs occurred during 7,732 catheter days (2.7 per 1,000 catheter days) in the 18-month period when CSS lines were used. After the introduction of MR CVCs, 21 catheter-related bloodstream infections occurred during 15,722 catheter days (1.4 per 1,000 catheter days). This represents a significant (p < 0.05) decrease in the CLABSI rate after introduction of MR CVCs. Mean length of time to infection developing after catheterization (8.6 days for CSS vs 6.1 days for MR) was also different (p = 0.04). The presence of MR did not alter the microbiologic profile of catheter-related infections, and it did not increase the incidence of resistant organisms.

CONCLUSIONS

The CLABSI rate decreased more with the use of MR CVCs compared with CSS CVCs in an ICU where the CLABSI rate was already low. The types of organisms causing infection were similar. With continued use of MR-impregnated CVCs in our ICU in the subsequent 5 years, we have seen sustained low rates of CLABSIs.

Characteristics of nosocomial bloodstream infections at a Hungarian cardiac surgery centre

Nosocomial bloodstream infection (BSI) is a common finding in cardiac surgery intensive care units and is associated with excess mortality and hospital costs. Additional data are needed about incidence, characteristics, predictors, associated microorganisms of nosocomial BSI in cardiac surgical patients in order to refine measures to prevent nosocomial infections and to improve recovery outcomes in this patient population. The 3912 cardio-thoracic surgery patients from all age groups were admitted to the study at the Gottsegen György Hungarian Institute of Cardiology between January 1999 and December 2000. In each patient with BSI demographic, epidemiological and clinical variables were recorded along with potential risk factors. Incidence of associated pathogens and their possible sources were evaluated and outcome and mortality risk factors were assessed. There were a total of 134 episodes of BSI. The incidence was 34.25 per 1000 admissions. The leading microorganisms were staphylococci (37.7%). Bacteremic episodes developed secondary to an identifiable source in 27.6% of the cases, or were catheter-related (16.4%). In 56% of the cases the source was not identified. The crude mortality rate was 33.3%. Higher mortality rate was associated with intracardial grafts (p < 0.05), low left ventricular ejection fraction (p < 0.04), diabetes mellitus (p < 0.05), an age above 16 years (p < 0.02), severe sepsis (p < 0.001) and high APACHE II score (p < 0.001). As the identified main sources of BSI were intravascular lines, mortality from BSI could probably be reduced by paying more attention to the prevention, early recognition and prompt management of intravascular device associated infections.

Robustness analysis of culturing perturbations on Escherichia coli colony biofilm beta-lactam and aminoglycoside antibiotic tolerance

Background

Biofilms are ubiquitous. For instance, the majority of medical infections are thought to involve biofilms. However even after decades of investigation, the in vivo efficacy of many antimicrobial strategies is still debated suggesting there is a need for better understanding of biofilm antimicrobial tolerances. The current study's goal is to characterize the robustness of biofilm antibiotic tolerance to medically and industrially relevant culturing perturbations. By definition, robust systems will return similar, predictable responses when perturbed while non-robust systems will return very different and potentially unpredictable responses. The predictability of an antibiotic tolerance response is essential to developing, testing, and employing antimicrobial strategies.

Results

The antibiotic tolerance of Escherichia coli colony biofilms was tested against beta-lactam and aminoglycoside class antibiotics. Control scenario tolerances were compared to tolerances under culturing perturbations including 1) different nutritional environments 2) different temperatures 3) interruption of cellular quorum sensing and 4) different biofilm culture ages. Here, antibiotic tolerance was defined in terms of culturable biofilm cells recovered after a twenty four hour antibiotic treatment.

Colony biofilm antibiotic tolerances were not robust to perturbations. Altering basic culturing parameters like nutritional environment or temperature resulted in very different, non-intuitive antibiotic tolerance responses. Some minor perturbations like increasing the glucose concentration from 0.1 to 1 g/L caused a ten million fold difference in culturable cells over a twenty four hour antibiotic treatment.

Conclusions

The current study presents a basis for robustness analysis of biofilm antibiotic tolerance. Biofilm antibiotic tolerance can vary in unpredictable manners based on modest changes in culturing conditions. Common antimicrobial testing methods, which only consider a single culturing condition, are not desirable since slight culturing variations can lead to very different outcomes. The presented data suggest it is essential to test antimicrobial strategies over a range of culturing perturbations relevant to the targeted application. In addition, the highly dynamic antibiotic tolerance responses observed here may explain why some current antimicrobial strategies occasionally fail.

Catheter-related bloodstream infection

Catheter-related bloodstream infections (CR-BSIs) are a common, frequently preventable complication of central venous catheterization. CR-BSIs can be prevented by strict attention to insertion and maintenance of central venous catheters and removing unneeded catheters as soon as possible. Antiseptic- or antibiotic-impregnated catheters are also an effective tool to prevent infections. The diagnosis of CR-BSI is made largely based on culture results. CR-BSIs should always be treated with antibiotics, and except in rare circumstances the infected catheter needs to be removed.

Central venous catheterization: a prospective, randomized, double-blind study

Central venous catheters (CVCs) are extensively used worldwide. Mechanical, infectious and thrombotic complications are well described with their use and may be associated with prolonged hospitalization, increased medical costs and mortality. CVCs account for an estimated 90% of all catheter-related bloodstream infections (CRBSI) and a host of risk factors for CVC-related infections have been documented. The duration of use of CVCs remains controversial and the length of time such devices can safely be left in place has not been fully and objectively addressed in the critically ill patient. Antimicrobial-impregnated catheters have been introduced in an attempt to limit catheter-related infection (CRI) and increase the time that CVCs can safely be left in situ. Recent meta-analyses concluded that antimicrobial-impregnated CVCs appear to be effective in reducing CRI. The authors conducted a prospective, randomized, double-blind study at Johannesburg Hospital over a 4-year period. The study entailed a comparison of standard triple-lumen versus antimicrobial impregnated CVCs on the rate of CRI. Our aim was to determine whether we could safely increase the duration of catheter insertion time from our standard practice of seven days to 14 days, to assess the influence of the antimicrobial impregnated catheter on the incidence of CRI, and to elucidate the epidemiology and risks of CRI. One hundred and eighteen critically ill patients were included in the study which spanned 34 951.5 catheter hours (3.99 catheter years). It was found that antimicrobial catheters did not provide any significant benefit over standard catheters, which the authors feel can safely be left in place for up to 14 days with appropriate infection control measures. The most common source of CRI was the skin. The administration of parenteral nutrition and the site of catheter insertion (internal jugular vein vs subclavian vein) were not noted to be risk factors for CRI. There was no clinical evidence of thrombotic complication in either of the study groups. This study offers direction for the use of CVCs in critically ill patients and addresses many of the controversies that exist.

Thrombotic and infectious complications of central venous catheters in patients with hematological malignancies

Central venous catheters (CVCs) have considerably improved the management of patients with hematological malignancies, by facilitating chemotherapy, supportive therapy and blood sampling. Complications of insertion of CVCs include mechanical (arterial puncture, pneumothorax), thrombotic and infectious complications. CVC-related thrombosis and infections are frequently occurring complications and may cause significant morbidity in patients with hematological malignancies. CVC-related thrombosis and infections are related and can therefore not be seen as separate entities. The incidence of symptomatic CVC-related thrombosis had been reported to vary between 1.2 and 13.0% of patients with hematological malignancy. The incidence of CVC-related bloodstream infections varies between 0.0 and 20.8%. There is need for a specific approach regarding diagnosis and treatment of CVC-related thrombosis and infection with specific attention to the preservation of the catheter. Since data on CVC-related infections and thrombosis in hematological patients have been obtained mainly from retrospective studies of small sample size, prospective, randomized studies of prophylactic measures concerning CVC-related thrombosis and infection are warranted.

Effect of Chlorhexidine/Silver Sulfadiazine-Impregnated Central Venous Catheters in an Intensive Care Unit with a Low Blood Stream Infection Rate after Implementation of an Educational Program: A Before–After Trial

BACKGROUND

Current guidelines recommend using antiseptic- or antibiotic-impregnated central venous catheters (CVCs) if, following a comprehensive strategy to prevent catheter-related blood stream infection (CR-BSI), infection rates remain above institutional goals based on benchmark values. The purpose of this study was to determine if chlorhexidine/silver sulfadiazine-impregnated CVCs could decrease the CR-BSI rate in an intensive care unit (ICU) with a low baseline infection rate.

METHODS

Pre-intervention and post-intervention observational study in a 24-bed surgical/trauma/burn ICU from October, 2002 to August, 2005. All patients requiring CVC placement after March, 2004 had a chlorhexidine/silver sulfadiazine-impregnated catheter inserted (post-intervention period).

RESULTS

Twenty-three CR-BSIs occurred in 6,960 catheter days (3.3 per 1,000 catheter days)during the 17-month control period. After introduction of chlorhexidine/silver sulfadiazine-impregnated catheters, 16 CR-BSIs occurred in 7,732 catheter days (2.1 per 1,000 catheter days; p = 0.16). The average length of time required for an infection to become established after catheterization was similar in the two groups (8.4 vs. 8.6 days; p = 0.85). Chlorhexidine/silver sulfadiazine-impregnated catheters did not result in a statistically significant change in the microbiological profile of CR-BSIs, nor did they increase the incidence of resistant organisms.

CONCLUSIONS

Although chlorhexidine/silver sulfadiazine-impregnated catheters are useful in specific patient populations, they did not result in a statistically significant decrease in the CR-BSI rate in this study, beyond what was achieved with education alone.

Prevention of catheter-related blood stream infection

PURPOSE OF REVIEW

Catheter-related blood stream infections are a morbid complication of central venous catheters. This review will highlight a comprehensive approach demonstrated to prevent catheter-related blood stream infections.

RECENT FINDINGS

Elements of prevention important to inserting a central venous catheter include proper hand hygiene, use of full barrier precautions, appropriate skin preparation with 2% chlorhexidine, and using the subclavian vein as the preferred anatomic site. Rigorous attention needs to be given to dressing care, and there should be daily assessment of the need for central venous catheters, with prompt removal as soon as is practicable. Healthcare workers should be educated routinely on methods to prevent catheter-related blood stream infections. If rates remain higher than benchmark levels despite proper bedside practice, antiseptic or antibiotic-impregnated catheters can also prevent infections effectively. A recent program utilizing these practices in 103 ICUs in Michigan resulted in a 66% decrease in infection rates.

SUMMARY

There is increasing recognition that a comprehensive strategy to prevent catheter-related blood stream infections can prevent most infections, if not all. This suggests that thousands of infections can potentially be averted if the simple practices outlined herein are followed.

Rifampicin-impregnated central venous catheters: a meta-analysis of randomized controlled trials

BACKGROUND

The use of antimicrobial-impregnated central venous catheters (CVCs) for the prevention of CVC microbial colonization and catheter-related bloodstream infection (CRBSI) remains controversial.

METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) evaluating CRBSI and colonization of CVCs impregnated with rifampicin-based antimicrobial combinations. Our main analysis compared the occurrence of CRBSI with rifampicin/minocycline-impregnated CVCs with that of non-rifampicin-impregnated CVCs. The PubMed and Cochrane Central Register of Controlled Trials databases were searched (until October 2006).

RESULTS

Eight RCTs were included in the analysis. The main analysis (seven RCTs) demonstrated that rifampicin/minocycline-impregnated CVCs were associated with fewer CRBSIs compared with catheters not impregnated with rifampicin/minocycline (OR 0.23, 95% CI 0.14-0.40). The same was true regarding colonization (OR 0.46, 95% CI 0.31-0.69). Further analysis, comparing rifampicin-based CVCs with non-rifampicin-impregnated CVCs, demonstrated superiority of rifampicin-based CVCs in reducing colonization (OR 0.38, 95% CI 0.24-0.62) and CRBSI (OR 0.24, 95% CI 0.14-0.40). Similar results, suggesting superiority of rifampicin/minocycline-impregnated CVCs, were noted in a subgroup analysis of colonization and CRBSIs in which rifampicin/minocycline-impregnated CVCs were compared with simple, non-tunnelled, non-antimicrobially impregnated CVCs, a subgroup analysis that was performed by excluding low quality RCTs, and a subgroup analysis for colonization comprising studies in which the sonication technique was used. No serious adverse events and no difference in mortality between the two treatment groups were reported. No clear conclusions can be made regarding the impact of the use of rifampicin/minocycline-impregnated CVCs on the development of antimicrobial resistance based on the available data.

CONCLUSIONS

The available evidence suggests that rifampicin/minocycline-impregnated CVCs are safe and effective in reducing the rate of catheter colonization and CRBSI. Further research should focus on the possible development of resistance and on pharmacoeconomic issues related to the use of rifampicin/minocycline-impregnated CVCs.

Prevention of catheter-related bloodstream infections: analysis of studies published between 2002 and 2005

As the most recent guidelines for the prevention of catheter-related bloodstream infections (CR-BSIs) were published four years ago, a systematic review was conducted to determine whether any recently published articles should further influence existing guidelines. Articles published between 2002 and 2005 dealing with infection control measures for prevention of CR-BSI were evaluated in order to identify evidence for the possible modification of routine practice. Special emphasis was placed on randomized controlled trials (RCTs), meta-analyses or systematic reviews, and studies applying multi-module interventions. Thirty-three RCTs and 10 meta-analyses or systematic reviews were retrieved. In addition, 10 cohort studies were identified where multi-module programmes were introduced for reducing CR-BSI rates. It was found that RCTs and meta-analyses only have a minor influence on the existing guidelines for the prevention of CR-BSIs and confirm the earlier recommendations on several points. Studies investigating multi-module programmes, however, found a substantial reduction in CR-BSIs ranging from 29% to 95%. The data show that many CR-BSIs are preventable and that there is room for improvement in many institutions. Simple interventions are often useful for reducing CR-BSI rates and the opportunities to decrease CR-BSI rates appear to be greatest when multi-module programmes are applied. An average reduction of more than 50% seems to be possible.