The promise of novel technology for the prevention of intravascular device-related bloodstream infection. I. Pathogenesis and short-term devices

Prevalence and Risk Factors of Healthcare-Associated Infections among Hospitalized Pediatric Patients: Point Prevalence Survey in Thailand 2021

BACKGROUND

Healthcare-associated infections (HAIs) pose a grave threat to patient safety, morbidity, and mortality, contributing to antimicrobial resistance. Thus, we estimated the point prevalence, risk factors, types, and pathogens of HAIs in hospitalized pediatric patients.

METHODS

A point prevalence survey (PPS) of HAIs in hospitalized pediatric patients < 18 years old was conducted from March to May 2021. Outcomes, risk factors, and types of HAIs associated with HAIs in 41 hospitals across Thailand were collected.

RESULTS

The prevalence of HAIs was 3.9% (95% CI 2.9-5.0%) (56/1443). By ages < 1 month, 1 month-2 years, 2-12 years, and 12-18 years, the prevalence of HAIs was 4.2%, 3.3%, 4.1%, and 3.0%, respectively (p = 0.80). Significant independent risk factors were extended hospital length of stay (LOS) and central venous catheter (CVC) use. Compared to an LOS of <4 days, LOSs of 4-7 days, 8-14 days, and >14 days had adjusted odds ratios (aORs) of 2.65 (95% CI 1.05, 6.68), 5.19 (95% CI 2.00, 13.4), and 9.03 (95% CI 3.97, 20.5), respectively. The use of a CVC had an aOR of 2.45 (95% CI 1.06-5.66). Lower respiratory tract infection (LRTI) was the most common HAI type (46.4%: 26/56). The highest prevalence of HAIs was predominantly observed in LRTI diagnoses, with the highest among these in the <1 month age category at 2.3% (17/738).

CONCLUSION

The prevalence of HAIs in hospitalized pediatric patients was 3.9%. Extended LOS and use of CVC were HAI risk factors. A strategy for reducing LOS and reviewing insertion indications or the early planned removal of a CVC was implemented. The surveillance of HAIs stands as a cornerstone and fundamental component of IPC, offering invaluable insights that enhance hospital IPC interventions aimed at preventing HAIs.

Relationship between chlorhexidine gluconate concentration and microbial colonization of patients' skin

OBJECTIVE

To characterize the relationship between chlorhexidine gluconate (CHG) skin concentration and skin microbial colonization.

DESIGN

Serial cross-sectional study.

SETTING/PARTICIPANTS

Adult patients in medical intensive care units (ICUs) from 7 hospitals; from 1 hospital, additional patients colonized with carbapenemase-producing Enterobacterales (CPE) from both ICU and non-ICU settings. All hospitals performed routine CHG bathing in the ICU.

METHODS

Skin swab samples were collected from adjacent areas of the neck, axilla, and inguinal region for microbial culture and CHG skin concentration measurement using a semiquantitative colorimetric assay. We used linear mixed effects multilevel models to analyze the relationship between CHG concentration and microbial detection. We explored threshold effects using additional models.

RESULTS

We collected samples from 736 of 759 (97%) eligible ICU patients and 68 patients colonized with CPE. On skin, gram-positive bacteria were cultured most frequently (93% of patients), followed by Candida species (26%) and gram-negative bacteria (20%). The adjusted odds of microbial recovery for every twofold increase in CHG skin concentration were 0.84 (95% CI, 0.80-0.87; P < .001) for gram-positive bacteria, 0.93 (95% CI, 0.89-0.98; P = .008) for Candida species, 0.96 (95% CI, 0.91-1.02; P = .17) for gram-negative bacteria, and 0.94 (95% CI, 0.84-1.06; P = .33) for CPE. A threshold CHG skin concentration for reduced microbial detection was not observed.

CONCLUSIONS

On a cross-sectional basis, higher CHG skin concentrations were associated with less detection of gram-positive bacteria and Candida species on the skin, but not gram-negative bacteria, including CPE. For infection prevention, targeting higher CHG skin concentrations may improve control of certain pathogens.

Nosocomial Infections in the Neonatal Intensive Care Unit

Nosocomial infections are relatively common in the NICU. These infections increase morbidity and mortality, particularly in the smallest and most fragile infants. The impact of these infections on long-term outcomes and health-care costs is devastating. Worldwide efforts to decrease the incidence of nosocomial infections have focused on implementing specific prevention protocols such as handwashing, central line teams, care bundles, and antimicrobial stewardship. This review summarizes common nosocomial infections in patients in the NICU.

Antimicrobial efficacy of a nitric oxide-releasing ampicillin conjugate catheter lock solution on clinically-isolated antibiotic-resistant bacteria

Antibiotic lock therapy (ALT) is standard clinical practice for treating bacteremia linked with catheter-related bloodstream infections (CRBSIs). However, this strategy frequently fails against multi-drug-resistant bacteria in clinical settings. In this study, a novel approach to utilize a nitric oxide (NO) donor S-nitroso-N-acetyl-penicillamine (SNAP)-conjugated to ampicillin antibiotic (namely SNAPicillin) as a catheter lock solution is presented. The conjugate of two antimicrobial agents is anticipated to overcome the challenges of bacterial infection caused by antibiotic-resistant bacteria in ALT applications. Nitric oxide release from the SNAPicillin lock solution at varying concentrations was measured at 0 and 24 h time points in a catheter model system, which revealed tunable NO release at physiological levels. The clinical strains of E. coli (CDC AR-0089) and S. marcescens (CDC AR-0099) were screened using a zone of inhibition assay against standard antibiotics which confirmed the antibiotic resistance in bacteria. The minimum inhibitory concentration (MIC) testing of SNAPicillin unveiled the lowest MIC value for SNAPicillin against both E. coli and S. marcescens (1 and 2 mM of SNAPicillin, respectively) with an 8.24- and 4.28-log reduction in bacterial load compared to controls, respectively. In addition, while the ampicillin-treated biofilm demonstrated resistance toward the antibiotic, SNAPicillin led to >99% reduction in exterminating biofilm buildup on polymeric catheter surfaces. Lastly, the SNAPicillin lock solution was determined to be biocompatible via hemolysis and cell compatibility studies. Together, these results emphasize the promising potential of SNAPicillin lock solution with the dual-action of NO and ampicillin in overcoming bacterial challenges on medical devices like central venous catheters and other medical device interfaces.

Late-Onset Sepsis Among Very Preterm Infants

OBJECTIVES

To determine the epidemiology, microbiology, and associated outcomes of late-onset sepsis among very preterm infants using a large and nationally representative cohort of NICUs across the United States.

METHODS

Prospective observational study of very preterm infants born 401 to 1500 g and/or 22 to 29 weeks' gestational age (GA) from January 1, 2018, to December 31, 2020, who survived >3 days in 774 participating Vermont Oxford Network centers. Late-onset sepsis was defined as isolation of a pathogenic bacteria from blood and/or cerebrospinal fluid, or fungi from blood, obtained >3 days after birth. Demographics, clinical characteristics, and outcomes were compared between infants with and without late-onset sepsis.

RESULTS

Of 118 650 infants, 10 501 (8.9%) had late-onset sepsis for an incidence rate of 88.5 per 1000 (99% confidence interval [CI] [86.4-90.7]). Incidence was highest for infants born ≤23 weeks GA (322.0 per 1000, 99% CI [306.3-338.1]). The most common pathogens were coagulase negative staphylococci (29.3%) and Staphylococcus aureus (23.0%), but 34 different pathogens were identified. Infected infants had lower survival (adjusted risk ratio [aRR] 0.89, 95% CI [0.87-0.90]) and increased risks of home oxygen (aRR 1.32, 95% CI [1.26-1.38]), tracheostomy (aRR 2.88, 95% CI [2.47-3.37]), and gastrostomy (aRR 2.09, 95% CI [1.93-2.57]) among survivors.

CONCLUSIONS

A substantial proportion of very preterm infants continue to suffer late-onset sepsis, particularly those born at the lowest GAs. Infected infants had higher mortality, and survivors had increased risks of technology-dependent chronic morbidities. The persistent burden and diverse microbiology of late-onset sepsis among very preterm infants underscore the need for innovative and potentially organism-specific prevention strategies.

Changes in Central Line–Associated Bloodstream Infection (CLABSI) Rates Following Implementation of Levofloxacin Prophylaxis for Children and Adolescents With High-Risk Leukemia

Background: Despite initiatives to reduce central line–associated bloodstream infection (CLABSI), children and adolescents with hematologic malignancies, as well as those with relapsed disease, remain at the greatest risk for infection. This single-institution project evaluated changes in CLABSI rates following implementation of antibacterial prophylaxis with levofloxacin for patients with high-risk hematologic malignancies. Methods: Positive blood culture events meeting National Health Safety Network surveillance criteria to be classified as CLABSIs from January 1, 2006, to December 31, 2019, were included. Data were organized into four time periods for comparison based on implementation of CLABSI-reduction interventions. Conditional Poisson regression models were used to evaluate the effect of time (intervention period) on CLABSI rates with post hoc Tukey pairwise comparisons between each of the four time periods. Results: From 2006 and 2019, 227 patients experienced 310 CLABSIs. Clinically important decreases in CLABSI rates from baseline (4.84 per 1,000 line days) occurred with implementation of Children's Hospital Association (CHA) bundles (3.29 per 1,000 line days); however, this difference was not significant ( p  =  .16). CLABSI rates decreased from baseline with the addition of formalized supportive cares (2.66 per 1,000 line days; incidence rate ratio [IRR]  =  0.60; p < .01), and with the use of antibacterial prophylaxis (1.66 per 1,000 line days; IRR  =  0.35; p < .01). Post hoc comparisons indicated decreased CLABSI rates with the use of antibacterial prophylaxis compared with CHA bundles alone (IRR  =  0.49; p  =  .011) and CHA bundles plus formalized supportive cares (IRR  =  0.58; p  =  .046). Discussion: Results demonstrate sustained success using a practice-based evidence approach to guide CLABSI-reduction interventions. Follow-up research, applying machine learning algorithms, may identify additional risk factors and inform future interventions.

Antimicrobial-free graphene nanocoating decreases fungal yeast-to-hyphal switching and maturation of cross-kingdom biofilms containing clinical and antibiotic-resistant bacteria

Candida albicans and methicillin-resistant Staphylococcus aureus (MRSA) synergize in cross-kingdom biofilms to increase the risk of mortality and morbidity due to high resistance to immune and antimicrobial defenses. Biomedical devices and implants made with titanium are vulnerable to infections that may demand their surgical removal from the infected sites. Graphene nanocoating (GN) has promising anti-adhesive properties against C. albicans. Thus, we hypothesized that GN could prevent fungal yeast-to-hyphal switching and the development of cross-kingdom biofilms. Herein, titanium (Control) was coated with high-quality GN (coverage > 99%). Thereafter, mixed-species biofilms (C. albicans combined with S. aureus or MRSA) were allowed to develop on GN and Control. There were significant reductions in the number of viable cells, metabolic activity, and biofilm biomass on GN compared with the Control (CFU counting, XTT reduction, and crystal violet assays). Also, biofilms on GN were sparse and fragmented, whereas the Control presented several bacterial cells co-aggregating with intertwined hyphal elements (confocal and scanning electronic microscopy). Finally, GN did not induce hemolysis, an essential characteristic for blood-contacting biomaterials and devices. Thus, GN significantly inhibited the formation and maturation of deadly cross-kingdom biofilms, which can be advantageous to avoid infection and surgical removal of infected devices.

Smartphone compatible nitric oxide releasing insert to prevent catheter-associated infections

A large fraction of nosocomial infections is associated with medical devices that are deemed life-threatening in immunocompromised patients. Medical device-related infections are a result of bacterial colonization and biofilm formation on the device surface that affects >1 million people annually in the US alone. Over the past few years, light-based antimicrobial therapy has made substantial advances in tackling microbial colonization. Taking the advantage of light and antibacterial properties of nitric oxide (NO), for the first time, a robust, biocompatible, anti-infective approach to design a universal disposable catheter disinfection insert (DCDI) that can both prevent bacterial adhesion and disinfect indwelling catheters in situ is reported. The DCDI is engineered using a photo-initiated NO donor molecule, incorporated in polymer tubing that is mounted on a side glow fiber optic connected to an LED light source. Using a smartphone application, the NO release from DCDI is photoactivated via white light resulting in tunable physiological levels of NO for up to 24 h. When challenged with microorganisms S. aureus and E. coli, the NO-releasing DCDI statistically reduced microbial attachment by >99% versus the controls with just 4 h of exposure. The DCDI also eradicated ∼97% of pre-colonized bacteria on the CVC catheter model demonstrating the ability to exterminate an established catheter infection. The smart, mobile-operated novel universal antibacterial device can be used to both prevent catheter infections or can be inserted within an infected catheter to eradicate the bacteria without complex surgical interventions. The therapeutic levels of NO generated via illuminating fiber optics can be the next-generation biocompatible solution for catheter-related bloodstream infections.

Clinical outcomes of suspected Catheter Related Blood Stream Infection at a tertiary care center in south India

BACKGROUND

Catheter related blood stream infection (CRBSI) makes up a significant proportion of Hospital acquired infection and increases the morbidity and mortality of those affected.

AIMS AND OBJECTIVES

Primary aim was to study the clinical outcomes of patients with suspected Catheter Related Blood Stream Infection (CRBSI).

RESULTS

Of the 150 participants suspected of having CRBSI, 100(67%) had CRBSI, 26(16%) patients were colonizers and 24(17%) patients had BSI from another source. Gram negative microbes were predominant. Clinical outcomes were studied with respect to mortality, complications and length of hospital stay. CRBSI participants had a significantly prolonged hospital stay. However no specific factors related to the host or the pathogen influenced this outcome.

CONCLUSION

CRBSI prolongs the hospital stay for patients who would have otherwise been discharged, hence increases the burden on hospital and human resources.

Human blood plasma factors affect the adhesion kinetics of Staphylococcus aureus to central venous catheters

Staphylococcus aureus is a common cause of catheter-related blood stream infections (CRBSI). The bacterium has the ability to form multilayered biofilms on implanted material, which usually requires the removal of the implanted medical device. A first major step of this biofilm formation is the initial adhesion of the bacterium to the artificial surface. Here, we used single-cell force spectroscopy (SCFS) to study the initial adhesion of S. aureus to central venous catheters (CVCs). SCFS performed with S. aureus on the surfaces of naïve CVCs produced comparable maximum adhesion forces on three types of CVCs in the low nN range (~ 2–7 nN). These values were drastically reduced, when CVC surfaces were preincubated with human blood plasma or human serum albumin, and similar reductions were observed when S. aureus cells were probed with freshly explanted CVCs withdrawn from patients without CRBSI. These findings indicate that the initial adhesion capacity of S. aureus to CVC tubing is markedly reduced, once the CVC is inserted into the vein, and that the risk of contamination of the CVC tubing by S. aureus during the insertion process might be reduced by a preconditioning of the CVC surface with blood plasma or serum albumin.

Routine scrubbing reduced central line associated bloodstream infection in NICU

BACKGROUND

The main aim of this study was to estimate the effectiveness of routine scrubbing by change of the incidence of central line-associated bloodstream infections (CLABSI).

METHODS

We surveyed cultures from the NICU environment in December 2017. We found that areas close to infants harbored more bacteria. We implemented routine scrubbing to control sites with the most bacteria starting from January 2018. We retrospectively reviewed and compared the data between the pre (2017) and post (2018) intervention periods.

RESULTS

A total of 916 infants were included; 10 CLABSI episodes were identified, 9 and 1 episodes in the pre- and postintervention periods, respectively. We found that the incidence of CLABSI decreased significantly among all admitted infants (P = .006) and also among very low birth weight infants (P = .085). The number of CLABSI cases per 1,000 central line days decreased from 1.89 in 2017 to 0.23 in 2018 (P = .018). The most common bacterial species found in the cultures established from the NICU environment were identical to the CLABSI-causing coagulase-negative Staphylococcus.

CONCLUSIONS

Routine scrubbing significantly reduced CLABSI in the NICU.

Tryptophol Coating Reduces Catheter-Related Cerebral and Pulmonary Infections by Scedosporium apiospermum

Introduction

Central venous catheter (CVC) is a medical device that is used to administer medication for a long duration. Colonization by an emerging opportunistic pathogen Scedosporium apiospermum in the CVC lumen is frequently reported to cause severe complications in patients. Here, we describe the effect of fungal quorum-sensing molecule (QSM) known as tryptophol (TOH) to control S. apiospermum colonization in catheter tube lumens in both in vitro and in vivo models.

Methods

Antifungal susceptibility of TOH against S. apiospermum was compared with voriconazole, and the colony diameter was determined on days 2, 4, and 6. Experimental catheterization rat model was conducted with pre-coating of TOH and voriconazole or an uncoated control and an infection with S. apiospermum. Biofilm formation on the catheter luminal surface was assessed using the scanning electron microscopy, crystal violet, and 2,3-bis(2-methoxy-4-ni-tro-5-sulfophenyl)-5-(phenylamino)-carbonyl-2H-tetra-zolium hydroxide (XTT) reduction assays. Brain and lung samples of catheterized rats were histopathologically assessed. Serum samples from catheterized rats were injected into Galleria mellonella larvae. Survival of catheterized rats and G. mellonella was determined.

Results

TOH impeded the growth of S. apiospermum by reducing the colony diameter in a dose-dependent manner. TOH coating remarkably lessened S. apiospermum biofilm formation and fungal cell viability on the catheter luminal surface. Additionally, TOH coating lessens cerebral edema that is associated with abscess and invasive pulmonary damages due to S. apiospermum catheter-related infection. Furthermore, TOH coating also lessened the virulence of S. apiospermum in sera of experimental catheterized rats and extended the survival rate of larvae Galleria mellonella infection model.

Conclusion

An alternative modification of catheter by coating with TOH is effective in preventing S. apiospermum colonization in vivo. Our study gives a new strategy to control catheter contamination and prevents nosocomial diseases due to S. apiospermum infection.

Efficacy of chlorhexidine patches on central line-associated bloodstream infections in children

BACKGROUND

Central line-associated bloodstream infections (CLABSIs) are important hospital-acquired infections. Chlorhexidine-impregnated dressings (also known as chlorhexidine patches, CHG patches) are reported to decrease CLABSIs in adults. This study aims to determine the efficacy of CHG patches in reducing CLABSIs in children.

METHODS

An open-label randomized controlled trial was conducted in children aged 2 months to 18 years, requiring a short-term catheter. Patients were randomized into two groups, allocated to receive CHG patches or standard transparent dressings. Care of the catheter was in accordance with Asia Pacific Society of Infection Control (APSIC) recommendations. Central-line-associated bloodstream infections were defined using National Healthcare Safety Network surveillance criteria.

RESULTS

From April 2017 to April 2018, 192 children were enrolled. There were 108 CHG patch catheters and 101 standard dressing catheters, contributing to 3,113 catheter days. The median duration of catheter dwelling was 13 days, with an interquartile range (IQR) of 8-20 days. Half were placed at the jugular vein and 22% at the femoral vein. There were 23 CLABSI events. Incidence rates for CHG patches and standard dressings were 7.98 (95% confidence interval (CI), 4.25-13.65) and 6.74 (95% CI, 3.23-12.39) per 1,000 catheter days, respectively (incidence rate ratio 1.18; 95% CI, 0.52-2.70). The CLABSI pathogens were 15 Gram-negative bacteria, six Gram-positive bacteria, and two Candida organisms. Catheter colonization of CHG patches and standard dressings were 2.02 (95% CI, 0.42-5.91) and 3.07 (95% CI, 1.00-7.16) per 1,000 catheter days, respectively. Only local adverse effects occurred in 6.8% of the participants.

CONCLUSIONS

In our setting, there was no difference in CLABSI rates when the chlorhexidine patch dressings were compared with the standard transparent dressings. Strengthening of CLABSI prevention bundles is mandatory.

Venue of catheter insertion does not significantly impact the event of central line-associated bloodstream infection in patients with haematological diseases

Background

Central line-associated bloodstream infection (CLABSI) is a serious complication of central venous catheter (CVC) placement in patients with haematological diseases associated with neutropenia and immunosuppression. However, whether the venues where CVC are inserted influence CLABSI development remains unclear.

Methods

We investigated whether CVC insertion at venues with different standards of cleanliness altered the occurrence of CLABSI. We evaluated data from 279 patients (545 CVC insertions) with haematological diseases including age, sex, underlying disease, reason for insertion, insertion site, number of lumens, venue, dates of insertion and removal, complete blood counts, percentage of neutrophils and serum albumin concentrations at the time of CVC insertion.

Findings

Overall, 55 CLABSI events occurred during a period of 23,434 catheter days (2.35 per 1,000 catheter days). In total, 153 and 190 patients underwent 226 and 305 CVC insertions, respectively in a ward and in an operating room, respectively. Univariate analysis identified the operating room (P = 0.017), allogeneic haematopoietic stem cell transplantation (P < 0.001), triple lumen catheter (P = 0.002), haemoglobin (P = 0.019), white blood cell count (P = 0.012) and percentage of neutrophils (P = 0.012) as significant factors for the development of CLABSI. However, multivariate analysis adjusted for age, reason for insertion, insertion site, number of lumens, haemoglobin, percentage of neutrophils and platelet counts found no significant differences between the venue where CVC were inserted and CLABSI development (P = 0.158).

Conclusion

The venue of CVC insertion is unlikely to influence CLABSI development in patients with haematological diseases.

Septic pulmonary emboli as a complication of peripheral venous cannula insertion

Septic pulmonary emboli can occur as a complication of many diseases, most common being right sided infective endocarditis. Septic emboli through a peripheral venous cannula are rarely reported in literature though central venous catheter is commonly implicated. We describe a case of widespread cellulitis and septic pulmonary emboli as a complication of peripheral venous cannulation.

Accepted but Unacceptable: Peripheral IV Catheter Failure

Peripheral intravenous (IV) catheter insertion, the most common invasive hospital procedure performed worldwide, is associated with a variety of complications and an unacceptably high overall failure rate of 35% to 50% in even the best of hands. Catheter failure is costly to patients, caregivers, and the health care system. Although advances have been made, analysis of the mechanisms underlying the persistent high rate of peripheral IV failure reveals opportunities for improvement.

Inhibition of bacterial attachment and biofilm formation by a novel intravenous catheter material using an in vitro percutaneous catheter insertion model

Introduction

Despite sterile barrier precautions and vigorous skin antisepsis, percutaneous insertion of intravenous catheters has been shown to result in attachment to the catheter surface of bacteria residing in the deep structures of the skin. Such attachment poses the risk of biofilm formation and eventual catheter-related bloodstream infection (CRBSI). This study was undertaken to assess whether the non-coated surface treatment of a unique catheter material (ChronoFlex C^® with BioGUARD™) could inhibit bacterial attachment and biofilm formation.

Methods

A novel in vitro model and fluorescence microscopy were used to compare two intravascular catheter materials with respect to bacterial attachment and biofilm formation. The control material was a commonly used polyurethane. The study material was a unique copolymer, treated so as to remove surface additives, alter hydrophobicity and create surface micro-patterning. Outcomes were assessed using both a membrane potential indicator and a cell death reporter with appropriate fluorescent channels. Thus, bacterial cells attached to the catheter surface (living and dead) were imaged without mechanical disruption.

Results

Both bacterial attachment and biofilm formation are significantly inhibited by the study catheter material. In fact, over 5 times more bacteria were able to attach and grow on the control polyurethane material than on the study material (P=0.0020). Moreover, those few bacteria that were able to attach to the study material had a 1.5 times greater likelihood of dying.

Conclusion

Using a novel in vitro percutaneous catheter insertion model, ChronoFlex C with BioGUARD is proven to significantly inhibit bacterial attachment and biofilm formation as compared with a commonly used polyurethane catheter material.

Central line-associated bloodstream infections in neonates

Newborn infants, including premature infants, are high-risk patients susceptible to various microorganisms. Catheter-related bloodstream infections are the most common type of nosocomial infections in this population. Regular education and training of medical staffs are most important as a preventive strategy for central line-associated bloodstream infections (CLABSIs). Bundle approaches and the use of checklists during the insertion and maintenance of central catheters are effective measures to reduce the incidence of CLABSIs. Chlorhexidine, commonly used as a skin disinfectant before catheter insertion and dressing replacement, is not approved for infants <2 months of age, but is usually used in many neonatal intensive care units due to the lack of alternatives. Chlorhexidine-impregnated dressing and bathing, recommended for adults, cannot be applied to newborns. Appropriate replacement intervals for dressing and administration sets are similar to those recommended for adults. Umbilical catheters should not be used longer than 5 days for the umbilical arterial catheter and 14 days for the umbilical venous catheter. It is most important to regularly educate, train and give feedback to the medical staffs about the various preventive measures required at each stage from before insertion to removal of the catheter. Continuous efforts are needed to develop effective and safe infection control strategies for neonates and young infants.

Nitric oxide releasing vascular catheters for eradicating bacterial infection

The interaction of blood proteins with an implant surface is not only a fundamental phenomenon but is also key to several important medical complications. Plasma proteins binding on the surface of intravascular catheters can promote bacterial adhesion leading to the risk of local and systemic complications such as catheter-related blood infections (CRBIs). The incidences of CRBIs in the United States amount to more than 250,000 cases/year with an attributable mortality of up to 35% and an annual healthcare expenditure of $2.3 billion approximately. This demands the development of truly nonthrombogenic and antimicrobial catheters. In the present study, catheters were fabricated by incorporating a nitric oxide (NO) donor molecule, S-nitroso-N-acetyl-penicillamine (SNAP) in a hydrophobic medical grade polymer, Elasteon-E2As. NO offers antithrombotic and antibacterial attributes without promoting drug resistance and cytotoxicity. E2As-SNAP catheters were first coated with fibrinogen, a blood plasma protein plays a key role in clot formation and eventual bacterial adhesion to the implant surface. The suitability of the catheters for biomedical applications was tested in vitro for contact angle, NO release kinetics, inhibition of bacteria, and absence of cytotoxicity toward mammalian cells. The highly hydrophobic catheters released NO in the physiological range that inhibited >99% bacterial viability on fibrinogen-coated catheters in a 24 h study. No toxic response of E2As-SNAP catheters leachate was observed using a standard cytotoxicity assay with mouse fibroblast cells. Overall, the results showed that the E2As-SNAP catheters can inhibit viable bacteria even in the presence of blood proteins without causing a cytotoxic response. The fundamentals of this study are applicable to other blood-contacting medical devices as well. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2849-2857, 2018.

Infections in Neurocritical Care

Neurointensive care (NICU) patients experience complex infectious disease challenges. Central nervous system (CNS) infections are difficult to diagnose and treat, and post-neurosurgical patients are vulnerable to a unique set of healthcare-acquired infections (HAI) in addition to those typical of critically ill patients. The purpose of this review is to summarize the approach to suspected infection in the NICU and discuss management of several infectious syndromes in the NICU setting.

Comparative study on fixation of central venous catheter by suture versus adhesive device

OBJECTIVES

To assess the efficacy of a central venous catheter adhesive fixation device (CVC) to prevent associated complications. To establish the need for dressing changes, number of days' catheterization and reasons for catheter removal in both study groups. To assess the degree of satisfaction of personnel with the adhesive system.

METHOD

A, randomized, prospective and open pilot study, of parallel groups, with comparative evaluation between CVC fixation with suture and with an adhesive safety system. The study was performed in the Coronary Unit of the Universitari de Bellvitge Hospital, between April and November 2016. The population studied were patients with a CVC. The results were analyzed using SPSS Statistics software. The study was approved by the Clinical Research Ethics Committee.

RESULTS

100 patients (47 adhesive system and 53 suture) were analyzed. Both groups were homogeneous in terms of demographic variables, anticoagulation and days of catheterization. The frequency of complications in the adhesive system group was 21.3%, while in the suture group it was 47.2% (P=.01). The suture group had a higher frequency of local signs of infection (p=.006), catheter displacement (p=.005), and catheter-associated bacteraemia (P=.05). The use of adhesive fixation was associated with a lower requirement for dressing changes due to bleeding (P=.006). Ninety-six point seven percent of the staff recommended using the adhesive safety system.

CONCLUSIONS

The catheters fixed with adhesive systems had fewer infectious complications and less displacement.

Intravascular Catheters and Biofilm Control

Intravascular catheters are the most common cause of nosocomially acquired bloodstream infections. Bacteria found adhering to the intraluminal surfaces of catheters are the principal source and cause of these infections. Adherent bacteria overtime are known to form multicellular communities which become encased within a three dimensional matrix of extracellular polymeric material known as biofilms, which are thought to be responsible for persistent infections. Consequently, a number of technologies have been developed to help prevent and control biofilms in intravascular catheters. One such approach involves impregnating catheter material with antimicrobial agents. Unfortunately these methods are not universally effective in preventing catheter-related biofilm infections. Technologies that utilise antimicrobials, as catheter locks have been shown to have more potential for preventing biofilm formation and reducing the incidences of catheter related bloodstream infections (CRBSI). This article discusses the significance of biofilms in intravascular catheters and determines whether the treatments available today are proving to be effective for controlling biofilms and draws attention to future avenues which are being investigated to control biofilms and therefore CRBSI.

Modern Strategies in the Prevention of Implant-Associated Infections

The application of medical devices either for temporary or permanent use has become an indispensible part of almost all fields of medicine. However, foreign bodies are associated with a substantial risk of bacterial and fungal infections. Implant-associated infections significantly contribute to the still increasing problem of nosocomial infections.

To reduce the incidence of such infections, specific guidelines providing evidence-based recommendations and comprising both technological and nontechnological strategies for prevention have been established. Strict adherence to hygienic rules during insertion or implantation of the device are aspects of particular importance. Besides such basic and indispensable aspects, the development of new materials which could withstand microbial adherence and colonization has become a major topic in recent years. Modification of surface by primarily physico-chemical methods may lead to a change in specific and unspecific interactions with microorganisms and, thus, to a reduction in microbial adherence. Medical devices made out of a material that would be ideally antiadhesive or at least colonization-resistant would be the most suitable candidates to avoid colonization and subsequent infection. However, it appears impossible to create a surface with an absolute “zero”-adherence due to thermodynamical reasons and due to the fact that a modified material surface is in vivo rapidly covered by plasma and connective tissue proteins. Therefore, another concept for the prevention of implant-associated infections involves the impregnation of devices with various antimicrobial substances such as antibiotics, antiseptics, and/or metals.

In fact, already commercially available materials for clinical use such as antimicrobial catheters have been introduced, in part with considerable impact on subsequent infections. However, future studies are warranted to translate the knowledge on the pathogenesis of device-associated infections into applicable prevention strategies.

Anti-fouling strategies for central venous catheters

Central venous catheters (CVCs) are ubiquitous in the healthcare industry and carry two common complications, catheter related infections and occlusion, particularly by thrombus. Catheter-related bloodstream infections (CRBSI) are an important cause of nosocomial infections that increase patient morbidity, mortality, and hospital cost. Innovative design strategies for intravenous catheters can help reduce these preventable infections. Antimicrobial coatings can play a major role in preventing disease. These coatings can be divided into two major categories: drug eluting and non-drug eluting. Much of these catheter designs are targeted at preventing the formation of microbial biofilms that make treatment of CRBSI nearly impossible without removal of the intravenous device. Exciting developments in catheter impregnation with antibiotics as well as nanoscale surface design promise innovative changes in the way that physicians manage intravenous catheters. Occlusion of a catheter renders the catheter unusable and is often treated by tissue plasminogen activator administration or replacement of the line. Prevention of this complication requires a thorough understanding of the mechanisms of platelet aggregation, signaling and cross-linking. This article will look at the advances in biomaterial design specifically drug eluting, non-drug eluting, lubricious coatings and micropatterning as well as some of the characteristics of each as they relate to CVCs.

Comparative Analysis of Bacterial Community Composition and Structure in Clinically Symptomatic and Asymptomatic Central Venous Catheters

Totally implanted venous access ports (TIVAPs) are commonly used catheters for the management of acute or chronic pathologies. Although these devices improve health care, repeated use of this type of device for venous access over long periods of time is also associated with risk of colonization and infection by pathogenic bacteria, often originating from skin. However, although the skin microbiota is composed of both pathogenic and nonpathogenic bacteria, the extent and the consequences of TIVAP colonization by nonpathogenic bacteria have rarely been studied. Here, we used culture-dependent and 16S rRNA gene-based culture-independent approaches to identify differences in bacterial colonization of TIVAPs obtained from two French hospitals. To explore the relationships between nonpathogenic organisms colonizing TIVAPs and the potential risk of infection, we analyzed the bacterial community parameters between TIVAPs suspected (symptomatic) or not (asymptomatic) of infection. Although we did not find a particular species assemblage or community marker to distinguish infection risk on an individual sample level, we identified differences in bacterial community composition, diversity, and structure between clinically symptomatic and asymptomatic TIVAPs that could be explored further. This study therefore provides a new view of bacterial communities and colonization patterns in intravascular TIVAPs and suggests that microbial ecology approaches could improve our understanding of device-associated infections and could be a prognostic tool to monitor the evolution of bacterial communities in implants and their potential susceptibility to infections. IMPORTANCE Totally implanted venous access ports (TIVAPs) are commonly used implants for the management of acute or chronic pathologies. Although their use improves the patient's health care and quality of life, they are associated with a risk of infection and subsequent clinical complications, often leading to implant removal. While all TIVAPs appear to be colonized, only a fraction become infected, and the relationship between nonpathogenic organisms colonizing TIVAPs and the potential risk of infection is unknown. We explored bacteria present on TIVAPs implanted in patients with or without signs of TIVAP infection and identified differences in phylum composition and community structure. Our data suggest that the microbial ecology of intravascular devices could be predictive of TIVAP infection status and that ultimately a microbial ecological signature could be identified as a tool to predict TIVAP infection susceptibility and improve clinical management.

Inverse Opal Scaffolds and Their Biomedical Applications

Three-dimensional porous scaffolds play a pivotal role in tissue engineering and regenerative medicine by functioning as biomimetic substrates to manipulate cellular behaviors. While many techniques have been developed to fabricate porous scaffolds, most of them rely on stochastic processes that typically result in scaffolds with pores uncontrolled in terms of size, structure, and interconnectivity, greatly limiting their use in tissue regeneration. Inverse opal scaffolds, in contrast, possess uniform pores inheriting from the template comprised of a closely packed lattice of monodispersed microspheres. The key parameters of such scaffolds, including architecture, pore structure, porosity, and interconnectivity, can all be made uniform across the same sample and among different samples. In conjunction with a tight control over pore sizes, inverse opal scaffolds have found widespread use in biomedical applications. In this review, we provide a detailed discussion on this new class of advanced materials. After a brief introduction to their history and fabrication, we highlight the unique advantages of inverse opal scaffolds over their non-uniform counterparts. We then showcase their broad applications in tissue engineering and regenerative medicine, followed by a summary and perspective on future directions.

Influence of biofilm lubricity on shear-induced transmission of staphylococcal biofilms from stainless steel to silicone rubber

In real-life situations, bacteria are often transmitted from biofilms growing on donor surfaces to receiver ones. Bacterial transmission is more complex than adhesion, involving bacterial detachment from donor and subsequent adhesion to receiver surfaces. Here, we describe a new device to study shear-induced bacterial transmission from a (stainless steel) pipe to a (silicone rubber) tube and compare transmission of EPS-producing and non-EPS-producing staphylococci. Transmission of an entire biofilm from the donor to the receiver tube did not occur, indicative of cohesive failure in the biofilm rather than of adhesive failure at the donor-biofilm interface. Biofilm was gradually transmitted over an increasing length of receiver tube, occurring mostly to the first 50 cm of the receiver tube. Under high-shearing velocity, transmission of non-EPS-producing bacteria to the second half decreased non-linearly, likely due to rapid thinning of the lowly lubricious biofilm. Oppositely, transmission of EPS-producing strains to the second tube half was not affected by higher shearing velocity due to the high lubricity and stress relaxation of the EPS-rich biofilms, ensuring continued contact with the receiver. The non-linear decrease of ongoing bacterial transmission under high-shearing velocity is new and of relevance in for instance, high-speed food slicers and food packaging.

Paraoxonases and infectious diseases

The paraoxonases (PON1, PON2 and PON3) are an enzyme family with a high structural homology. All of them have lactonase activity and degrade lipid peroxides in lipoproteins and cells. As such, they play a role in protection against oxidation and inflammation. Infectious diseases are often associated with oxidative stress and an inflammatory response. Infection and inflammation trigger a cascade of reactions in the host, known as the acute-phase response. This response is associated with dramatic changes in serum proteins and lipoproteins, including a decrease in serum PON1 activity. These alterations have clinical consequences for the infected patient, including an increased risk for cardiovascular diseases, and an impaired protection against the formation of antibiotic-resistant bacterial biofilms. Several studies have investigated the value of serum PON1 measurement as a biomarker of the infection process. Low serum PON1 activities are associated with poor survival in patients with severe sepsis. In addition, preliminary studies suggest that serum PON1 concentration and/or enzyme activity may be useful as markers of acute concomitant infection in patients with an indwelling central venous catheter. Investigating the associations between paraoxonases and infectious diseases is a recent, and productive, line of research.

Incidence of central venous catheter hub contamination

PURPOSE

To investigate microorganisms causing central venous catheter contamination and how this contamination differs across different catheter metrics.

MATERIALS AND METHODS

After obtaining IRB approval and informed consent, 830 cultures were prospectively obtained from 45 ICU patients with central venous catheter or peripherally inserted central catheter. Bacterial colonies were identified by mass spectrometry.

RESULTS

Bacterial contamination of central catheter hubs occurred 44% of the time in this study in the ICU setting. Coagulase-positive staphylococci cultures had higher median (±interquartile range) CFUs (12±232) versus coagulase-negative (3±10) and other bacteria (1±3; P<0.001). Bacterial contamination was associated with various metrics. Higher incidence (P<0.05) of coagulase-positive staphylococci cultures was associated with hub-only connections (a "hub" being a female connection; 10.9% vs. 7.9% male connections), connections without a manifold (1lumen device that mixes multiple infusions together; 9.7% vs. 0% with manifold); and central venous pressure monitoring connections (25.8% vs. 7.1% without). Internal jugular sites (10.0% vs. 2.7% femoral, 6.2% PICC, P=0.031) and medial lumens of triple lumen catheters (11.9% vs. 5.6% distal, 7.0% proximal, P=0.049) had increased incidence of higher bacteria loads (>15 CFUs).

CONCLUSIONS

This study found a high incidence of central access catheter hub bacterial contamination, which correlated with positive blood cultures in 2 of 3 total bacteremia cases identified in the 45 patients.

Use of Ethanol Lock Therapy to Reduce the Incidence of Catheter-Related Bloodstream Infections in Home Parenteral Nutrition Patients

BACKGROUND

Catheter-related bloodstream infection (CRBSI) is a serious complication for home parenteral nutrition (HPN) patients. To reduce the incidence of infection in frequently infected HPN patients, prophylactic ethanol lock therapy (ELT) was initiated.

METHODS

Nine patients were selected as candidates for ELT because of their history of recurrent CRBSI. Diagnosis of CRBSI was determined by symptoms correlating with positive peripheral and access device blood cultures. Medical-grade ethyl alcohol 25%-70% was instilled into the central venous access device and allowed to dwell for 2-4 hours. The incidence of CRBSI and catheter changes was compared before and after initiation of ELT.

RESULTS

Nine patients experienced 81 CRBSIs (8.3 per 1,000 catheter-days) before starting ELT vs 9 infections (2.7 per 1,000 catheter-days: relative risk [RR], 0.325; confidence interval [CI] 95%, 0.17-0.64) after ELT. Catheter changes were also reduced from 69 (7.0 per 1000 days) before ELT to 1 (0.3 per 1,000 days: RR, 0.043; CI 95%, 0.01-0.25) after ELT. No significant adverse effects were noted, although some patients complained of transient dizziness and nausea.

CONCLUSIONS

ELT shows promise in reducing the incidence of CRBSI in the frequently infected HPN population. Further studies are warranted.

Techniques to Prevent Central Venous Catheter Infections: Products, Research, and Recommendations

Central venous catheters (CVCs) are commonly used to deliver a variety of therapies such as chemotherapy and parenteral nutrition. It is well known that there are complications associated with CVCs; a major complication is catheter-related bloodstream infection (CRBSI). Many strategies exist to prevent CVC complications and CRBSI. This paper will focus on the fight against CRBSI using 3 products at the catheter insertion site: 2% chlorhexidine, BioPatch, and transparent split dressings. Lists of key recommendations from national organizations for infection prevention are included.

Twenty-five Years of Advances in Vascular Access: Bridging Research to Clinical Practice

Vascular access has become a key component for a multitude of IV therapies, including parenteral nutrition. Access of the central venous system has been long recognized for its associated complications of infection, thrombosis, and occlusion. Over the past 25 years, clinical practice based on research and innovation has attempted to decrease complication rates and therefore improve the safety of vascular access. This article highlights the research and its influence on catheter care procedures, technology, and education that has led to advances in vascular access. An improved understanding of the pathophysiology associated with catheter-related complications and an ongoing evaluation of new treatment modalities has provided clinicians today with new options for improved patient care and the ability to preserve vascular access options for patients.

Accepted but unacceptable: peripheral IV catheter failure

Peripheral intravenous (IV) catheter insertion, the most common invasive hospital procedure performed worldwide, is associated with a variety of complications and an unacceptably high overall failure rate of 35% to 50% in even the best of hands. Catheter failure is costly to patients, caregivers, and the health care system. Although advances have been made, analysis of the mechanisms underlying the persistent high rate of peripheral IV failure reveals opportunities for improvement.

Co-release of dicloxacillin and thioridazine from catheter material containing an interpenetrating polymer network for inhibiting device-associated Staphylococcus aureus infection

Approximately half of all nosocomial bloodstream infections are caused by bacterial colonization of vascular catheters. Attempts have been made to improve devices using anti-adhesive or antimicrobial coatings; however, it is often difficult to bind coatings stably to catheter materials, and the low amounts of drug in thin-film coatings limit effective long-term release. Interpenetrating polymer networks (IPNs) are polymer hybrid materials with unique drug release properties. While IPNs have been extensively investigated for use in tablet- or capsule-based drug delivery systems, the potential for use of IPNs in drug release medical devices remains largely unexplored. Here, we investigated the use of silicone-hydrogel IPNs as a catheter material to provide slow anti-bacterial drug-release functionality. IPN catheters were produced by the sequential method, using supercritical CO₂ as a solvent to polymerize and crosslink poly(2-hydroxyethyl methacrylate) (PHEMA) in silicone elastomer. The design was tested against Staphylococcus aureus colonization after loading with dicloxacillin (DCX) alone or in combination with thioridazine (TDZ), the latter of which is known to synergistically potentiate the antibacterial effect of DCX against both methicillin-sensitive and methicillin-resistant S. aureus. The hydrophilic PHEMA component allowed for drug loading in the catheters by passive diffusion and provided controlled release properties. The drug-loaded IPN material inhibited bacterial growth on agar plates for up to two weeks and in blood cultures for up to five days, and it withstood 24h of seeding with resilient biofilm aggregates. The combined loading of DCX+TDZ enhanced the antibacterial efficiency in static in vitro experiments, although release analyses revealed that this effect was due to an enhanced loading capacity of DCX when co-loaded with TDZ. Lastly, the IPN catheters were tested in a novel porcine model of central venous catheter-related infection, in which drug-loaded IPN catheters were found to significantly decrease the frequency of infection.

Efficacy of ultraviolet C light at sublethal dose in combination with antistaphylococcal antibiotics to disinfect catheter biofilms of methicillin-susceptible and methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis in vitro

Background

Biofilm formation inside inserted medical devices leads to their failure and acts as a source of refractory infections. The ultraviolet C (UVC) light is a potential therapy that can be used against the biofilm of bacterial pathogens.

Objective

We evaluated the efficacy of sublethal dose of UVC light with anti-staphylococcal antibiotics against biofilms made from 30 isolates of methicillin-susceptible Staphylococcus aureus and methicillin-resistant S. aureus and S. epidermidis on vascular catheters.

Materials and methods

A novel biofilm device was used to assess the combined approach. The biofilms on the catheters were irradiated with the UVC light at 254 nm and irradiance of 6.4 mW followed by treatment with vancomycin or quinupristin/dalfopristin at twice their minimum bactericidal concentrations or with linezolid at 64 µg/mL for 24 hours. The catheters were cut into segments and sonicated, and the number of the sessile cells was determined colorimetrically using XTT viable cells assay. The effect of UVC radiation followed by treatment with an antistaphylococcal antibiotic on the viability of the bacteria in the biofilm was visualized using LIVE/DEAD BacLight bacterial viability stain and confocal laser scanning microscopy.

Results

Exposure of the bacterial biofilms to the UVC light or each of the antibiotics alone was ineffective in killing the bacteria. Treatment of the biofilms with the antibiotics following their exposure to UVC light significantly (P<0.001) reduced the number of viable cells within the biofilms but did not completely eradicate them.

Conclusion

To our knowledge, this combinatorial approach has not been investigated before. The combined approach can be used as a therapeutic modality for managing biofilm-associated infections by preventing the establishment of biofilms and/or disrupting the formed biofilms on the inserted medical devices with the goal of increasing their usefulness and preventing infectious complications. Further investigations are needed to assess the effectiveness of the combined approach in the clinical settings.

Disinfection of Needleless Catheter Connectors and Access Ports With Alcohol May Not Prevent Microbial Entry: The Promise of a Novel Antiseptic-Barrier Cap

Background.

Needleless valve connectors for vascular catheters are widely used throughout the United States because they reduce the risk of biohazardous injuries from needlesticks and exposure to bloodborne pathogens, such as human immunodeficiency virus and hepatitis C virus. Patients with long-term central venous catheters are at significant risk of acquiring catheter-related bloodstream infections caused by microbes that gain access through the connection between the administration set and the catheter or an injection port. Most healthcare practitioners wipe the membranous septum of the needleless connector or the injection port with 70% alcohol before accessing it. We report a simulation study of the efficacy of conventional alcohol disinfection before access, compared with that of a novel antiseptic-barrier cap that, when threaded onto a needleless luer-activated valved connector, allows a chlorhexidine-impregnated sponge to come into continuous contact with the membranous surface; after removal of the cap, there is no need to disinfect the surface with alcohol before accessing it.

Methods.

One hundred five commercial, needleless luer-activated valved connectors, each accessible by a blunt male-connector luer-lock attachment, were purchased from 3 manufacturers and were tested. The membranous septum of each test device was first heavily contaminated with ~105colony-forming units ofEnterococcus faecalisand then was allowed to dry for 24 hours. Fifteen of the contaminated devices were not disinfected (positive controls), 30 were conventionally disinfected with a commercial 70% alcohol pledget, and 60 had the antiseptic cap threaded onto the connector and then removed after 10 minutes. The test connectors were then accessed with a sterile syringe containing nutrient broth media, which was injected, captured on the downstream side of the intraluminal fluid pathway, and cultured quantitatively.

Results.

All 15 control connectors (100%) showed massive transmission of microorganisms across the membranous septum (4,500-10,000 colony-forming units). Of the 30 connectors accessed after conventional disinfection with 70% alcohol, 20 (67%) showed transmission of microorganisms (442-25,000 colony-forming units). In contrast, of the 60 connectors cultured after application of the novel antiseptic cap, only 1 (1.6%) showed any transmission of microorganisms (P<.001).

Conclusions.

The findings of this study show that, if the membranous septum of a needleless luer-activated connector is heavily contaminated, conventional disinfection with 70% alcohol does not reliably prevent entry of microorganisms. In contrast, the antiseptic-barrier cap provided a high level of protection, even in the presence of very heavy contamination. This novel technology deserves to be studied in a clinical trial.

Preventing Catheter-Associated Bloodstream Infections: A Survey of Policies for Insertion and Care of Central Venous Catheters From Hospitals in the Prevention Epicenter Program

Objective.

To determine the extent to which evidence-based practices for the prevention of central venous catheter (CVC)-associated bloodstream infections are incorporated into the policies and practices of academic intensive care units (ICUs) in the United States and to determine variations in the policies on CVC insertion, use, and care.

Design.

A 9-page written survey of practices and policies for nontunneled CVC insertion and care.

Setting.

ICUs in 10 academic tertiary-care hospitals.

Participants.

ICU medical directors and nurse managers.

Results.

Twenty-five ICUs were surveyed (1-6 ICUs per hospital). In 80% of the units, 5 separate groups of clinicians inserted 24%-50% of all nontunneled CVCs. In 56% of the units, placement of more than two-thirds of nontunneled CVCs was performed in a single location in the hospital. Twenty units (80%) had written policies for CVC insertion. Twenty-eight percent of units had a policy requiring maximal sterile-barrier precautions when CVCs were placed, and 52% of the units had formal educational programs with regard to CVC insertion. Eighty percent of the units had a policy requiring staff to perform hand hygiene before inserting CVCs, but only 36% and 60% of the units required hand hygiene before accessing a CVC and treating the exit site, respectively.

Conclusion.

ICU policy regarding the insertion and care of CVCs varies considerably from hospital to hospital. ICUs may be able to improve patient outcome if evidence-based guidelines for CVC insertion and care are implemented.

Why Is It That Internists Do Not Follow Guidelines for Preventing Intravascular Catheter Infections?

Background and Objective:

High morbidity of CVC-related infections has led to national guidelines for their prevention. Despite recommendations for the use of maximal barrier precautions (mask, sterile gloves, gown, and large drape) and skin antisepsis with 2% Chlorhexidine gluconate during CVC insertion, internists in the United States are not implementing these practices frequently. This study sought to identify and characterize the obstacles to and potential opportunities for improving adherence.

Design:

Cross-sectional survey.

Participants:

One thousand randomly selected physician-members of the American College of Physicians-American Society of Internal Medicine.

Methods:

Several potential determinants of adherence to maximal barrier precautions were assessed, including awareness of, agreement with, and ability to implement the recommendation, as well as the practice and training characteristics of the respondents. Factors influencing antiseptic selection were also recorded.

Results:

Of 526 respondents, 178 (34%) had recently inserted CVCs. Clinician experience and subspecialty, awareness of CDC guidelines, and external influences (eg, time to collect equipment) did not affect maximal barrier precautions adherence. The only independent predictor of adherence was high outcome expectancy for the use of large sterile drapes (OR, 5.3; CI95, 2.2-12.6). Availability had the greatest influence on internists' selection of specific antiseptic agents, whereas cost was the least important determinant.

Conclusions:

Despite established efficacy, use of maximal barrier precautions and Chlorhexidine gluconate is low among internists. Because improved adherence to these practices will require increased outcome expectancy for maximal barrier precautions and availability of Chlorhexidine gluconate, targeting these areas through focused education and systems modifications is essential (Infect Control Hosp Epidemiol2005;26:525-533).

Sampling for Collection of Central Line–Day Denominators in Surveillance of Healthcare-Associated Bloodstream Infections

Objective.

To determine the feasibility of estimating the number of central line-days at a hospital from a sample of months or individual days in a year, for surveillance of healthcare-associated bloodstream infections.

Design.

We used data reported to the National Nosocomial Infections Surveillance system in the adult and pediatric intensive care unit component for 1995-2003 and data from a sample of hospitals' daily counts of device use for 12 consecutive months. We calculated the percentile error as the central line-associated bloodstream infection percentile based on rates per line-days minus the percentile based on rates per estimated line-days.

Setting and Participants.

A total of 247 hospitals were used for sampling whole months and 12 hospitals were used for sampling individual days.

Results.

For a 1-month sample of central line–days data, the median percentile error was 3.3 (75th percentile, 7.9; 90th percentile, 15.4). The percentile error decreased with an increase in the number of months sampled. For a 3-month sample, the median percentile error was 1.4 (75th percentile, 4.3; 95th percentile, 8.3). Sampling individual days throughout the year yielded lower percentile errors than sampling an equivalent fraction of whole months. With 1 weekday sampled per week, the median percentile error ranged from 0.65 to 1.40, and the 90th percentile ranged from 2.8 to 5.0. Thus, for 90% of units, collecting data on line-days once a week provides an estimate within ± 5 percentile points of the true line-day rate.

Conclusion.

Sample-based estimates of central line-days can yield results that are acceptable for surveillance of healthcare-associated bloodstream infections.

Central Venous Access in the Pediatric Population With Emphasis on Complications and Prevention Strategies

Central venous catheters are often necessary in the pediatric population. Access may be challenging, and each vessel presents its own unique set of risks and complications. Central venous catheterization is useful for hemodynamic monitoring, rapid fluid infusion, and administration of hyperosmolar medications, including vasopressors, antibiotics, chemotherapy, and parenteral nutrition. Recent advances have improved the catheters used as well as techniques for insertion. A serious complication of central access is infection, which is associated with morbidity, mortality, and significant financial costs. Reduction of catheter-related bloodstream infections is realized with use of ethanol locks, single lumens when appropriate, and prudent adherence to insertion and maintenance bundles. Ultrasound guidance used for central venous catheter placement improves accuracy of placement, reducing time and unsuccessful insertion and complication rates. Patients with central venous catheters are best served by multidisciplinary team involvement.

Prevention of Device-Related Healthcare-Associated Infections

Healthcare-associated infections (HAIs) are a leading cause of morbidity and mortality in hospitalized patients. Up to 15% of patients develop an infection while hospitalized in the United States, which accounts for approximately 1.7 million HAIs, 99,000 deaths annually and over 10 billion dollars in costs per year. A significant percentage of HAIs are preventable using evidenced-based strategies. In terms of device-related HAIs it is estimated that 65-70% of catheter-line associated bloodstream infections (CLABSIs) and catheter-associated urinary tract infections (CAUTIs) are preventable. To prevent CLABSIs a bundle which includes hand hygiene prior to insertion and catheter manipulation, use of chlorhexidene alcohol for site preparation and maintenance, use of maximum barrier for catheter insertion, site selection, removing nonessential lines, disinfect catheter hubs before assessing line, and dressing changes are essential elements of basic practices. To prevent CAUTIs a bundle that includes hand hygiene for insertion and catheter or bag manipulation, inserting catheters for appropriate indications, insert using aseptic technique, remove catheters when no longer needed, maintain a close system keeping bag and tubing below the bladder are the key components of basic practices.

Clinical evaluation of a chlorhexidine intravascular catheter gel dressing on short-term central venous catheters

BACKGROUND

A major source of microbial colonization of short-term central venous catheters (CVC) is the patients' endogenous skin microorganisms located at the CVC insertion site. The aim of this study was to determine if a transparent film dressing incorporating a 2% (weight/weight) chlorhexidine gluconate (CHG) gel decreases CVC and insertion site microbial colonization compared with a nonantimicrobial dressing in adult patients in critical care.

METHODS

On CVC removal, samples for microbiological investigation were taken from both the skin surrounding the CVC insertion site and also from sutures securing the CVC. The sutures and intradermal and tip sections of the CVC were also collected for microbiological investigation. Microorganisms recovered from the samples were subsequently tested for susceptibility to CHG.

RESULTS

There was a significant reduction in the number of microorganisms recovered from the CVC insertion site, suture site, sutures, and catheter surface in the CHG dressing group (n = 136) compared with the nonantimicrobial dressing group (n = 137). There was no significant difference in susceptibility to CHG between the microorganisms isolated from the CHG and standard dressing study patients.

CONCLUSION

A film dressing incorporating a CHG gel pad significantly reduced the number of microorganisms at the CVC insertion and suture sites with concomitant reduced catheter colonization.

IV cannula securement: protecting the patient from infection

The use of venous cannulas to administer intravenous therapy is a common clinical intervention within the hospital setting. Once in situ, IV cannulas must be securely fixed in order to prevent their movement or displacement; as unsecured cannulas pose significant health risks, such as mechanical phlebitis and an increased risk of infection. This article explores some of the complications associated with inappropriately secured IV cannulas, along with a discussion on common securement devices.

Inactivation of Bacteria on Explanted Dialysis Catheter Lumens with Fiber Optically Delivered Ultraviolet Light

PURPOSE

To evaluate the germicidal effect of fiber optically delivered ultraviolet (UV) light on colonized explanted dialysis catheters.

MATERIALS AND METHODS

Explanted dialysis catheters were screened for intraluminal colonization by culturing 1 mL of a saline flush. Catheters growing >10 colony-forming units were treated with doses of fiber optically delivered UV light (range, 40-1,300 mJ/cm2). For each UV-treated catheter, an unexposed segment was first cut and set aside as a control sample. A sterile optical fiber was inserted into the catheter hub and advanced to the catheter tip. The fiber was slowly withdrawn at a constant rate while exposing the inner lumen to UV light. A second UV-exposed segment was then removed. The UV-exposed and control segments were split and sonicated to remove the adherent bacteria. The bacteria were counted and identified.

RESULTS

There were 14 colonized catheters treated with UV light. The catheters were primarily colonized with coagulase-negative staphylococci (60%) and Staphylococcus aureus (33%). There was a significant reduction in viable bacteria between the UV-treated versus untreated segments of each infected catheter (P = .04). In the seven treated catheters with >100,000 colony-forming units per cm2 of luminal surface area, there was a >99.5% reduction of viable bacteria in all UV-exposed samples, with no residual viable bacteria in four of seven (57%) of the samples.

CONCLUSIONS

This study demonstrates the technical feasibility and benchtop efficacy of using fiber optics to deliver UV light into the lumen of a colonized dialysis catheter and inactivating bacteria on the intraluminal surface.

Prediction of central venous catheter-related bloodstream infections (CRBSIs) in patients with haematologic malignancies using a modified Infection Probability Score (mIPS)

The aim of this study was to predict the probability of central venous catheter-related bloodstream infections (CRBSIs) in patients with haematologic malignancies using a modified version of the Infection Probability Score (mIPS). In order to perform a prospective, mono-centric surveillance of complications in clinical routine due to short-term central venous catheters (CVCs) in consecutive patients receiving chemotherapy from March 2013 to September 2014, IPS was calculated at CVC insertion and removal (mIPSin and mIPSex, respectively). We used the 2012 Infectious Diseases Working Party of the German Society of Haematology and Medical Oncology (AGIHO/DGHO) criteria to define CRBSI. In total, 143 patients (mean 59.5 years, 61.4 % male) with 267 triple-lumen CVCs (4044 CVC days; mean 15.1 days, range 1-60 days) were analysed. CVCs were inserted for therapy of acute leukaemia (53.2 %), multiple myeloma (24.3 %) or lymphoma (11.2 %), and 93.6 % were inserted in the jugular vein. A total of 66 CRBSI cases (24.7 %) were documented (12 definite/13 probable/41 possible). The incidence was 16.3/1000 CVC days (2.9/3.1/10.1 per 1000 CVC days for definite/probable/possible CRBSI, respectively). In CRBSI cases, the mIPSex was higher as compared to cases without CRBSI (13.1 vs. 7.1; p < 0.001). The best mIPSex cutoff for CRBSI prediction was 8 points (area under the curve (AUC) = 0.77; sensitivity = 84.9 %, specificity = 60.7 %, negative predictive value = 92.4 %). For patients with an mIPSex ≥8, the risk for a CRBSI was high (odds ratio [OR] = 5.9; p < 0.001) and even increased if, additionally, CVC had been in use for about 10 days (OR = 9.8; p < 0.001). In case other causes of infection are excluded, a mIPSex ≥8 and duration of CVC use of about 10 days predict a very high risk of CRBSI. Patients with a mIPSex <8 have a low risk of CRBSI of 8 %.