Effectiveness of antimicrobial-coated central venous catheters for preventing catheter-related blood-stream infections with the implementation of bundles: a systematic review and network meta-analysis

The antimicrobial effectiveness of chlorhexidine and chlorhexidine-silver sulfadiazine impregnated central venous catheters against the emerging fungal pathogen Candida auris

BACKGROUND

Candida auris is an emerging multidrug-resistant fungus associated with catheter-related bloodstream infections (CRBSI). In-vitro efficacy of chlorhexidine (CHX) and CHX/silver sulfadiazine-impregnated (CHX-S) antimicrobial central venous catheters (CVCs) against C. auris was investigated.

MATERIAL AND METHODS

Minimum inhibitory (MIC) and bactericidal (MBC) CHX concentrations were determined against nineteen C. auris isolates. To assess extraluminal efficacy, segments from CVCs impregnated externally (CHX-S1) and both externally and internally (CHX-S2) were plasma-conditioned for 1- and 6-days, and to assess intraluminal efficacy CHX-S2 CVCs were pre-conditioned with saline-lock for 6-days, followed by 24-hour C. auris inoculation and microbial adherence determination on impregnated and non-impregnated CVCs.

RESULTS

CHX inhibited all C. auris isolates with MIC and MBC range of 8-128 μg/mL. C. auris adherence was reduced on CHX-S1 and CHX-S2 extraluminally by 100% on day-1, 86.96%-100% on day-7, and intraluminally on CHX-S2 by 56.86%-90.52% on day-7.

DISCUSSION

CHX and CHX-S CVCs performance against C. auris observed in this study is consistent with antimicrobial benefits observed in prior pre-clinical and randomized controlled clinical studies.

CONCLUSIONS

CHX showed strong inhibitory and cidal effects on C. auris. CHX-S CVCs proved highly efficacious against this pathogen under in vitro conditions. Additional studies, however, are required to confirm clinical benefit.

Hydroxyl silicone oil grafting onto a rough thermoplastic polyurethane surface created durable super-hydrophobicity

Indwelling medical catheters are frequently utilized in medical procedures, but they are highly susceptible to infection, posing a vital challenge for both health workers and patients. In this study, the superhydrophobic micro-nanostructure surface was constructed on the surface of thermoplastic polyurethane (TPU) membrane using heavy calcium carbonate (CaCO3) template. To decrease the surface free energy, hydroxyl silicone oil was grafted onto the surface, forming a super-hydrophobic surface. The water contact angle (WCA) increased from 91.1° to 143 ± 3° when the concentration of heavy calcium CaCO3 was 20% (weight-to-volume (w/v)). However, the increased WCA was unstable and tended to decrease over time. After grafting hydroxyl silicone oil, the WCA rose to 152.05 ± 1.62° and remained consistently high for a period of 30 min. Attenuated total reflection infrared spectroscopy (ATR-FTIR) analysis revealed a chemical crosslinking between silicone oil and the surface of TPU. Furthermore, Scanning electron microscope (SEM) image showed the presence of numerous nanoparticles on the micro surface. Atomic force microscope (AFM) testing indicated a significant improvement in surface roughness. This method of creating a hydrophobic surface demonstrated several advantages, including resistance to cell, bacterial, protein, and platelet adhesion and good biosecurity. Therefore, it holds promising potential for application in the development of TPU-based medical catheters with antibacterial properties.

Practices to prevent central line-associated bloodstream infection: A 2021 survey of infection preventionists in US hospitals

OBJECTIVE

To determine prevalence of technical and behavioral interventions aimed at preventing central line-associated bloodstream infection (CLABSI) following the COVID19 pandemic.

DESIGN

Cross-sectional survey.

SETTING

US acute care hospitals.

PARTICIPANTS

Infection preventionists at participating hospitals.

METHODS

Surveys were sent to infection preventionists from a national random sample of 881 US acute care hospitals. Questions covered use of technical interventions to prevent CLABSI (eg, alcohol-containing chlorhexidine gluconate [CHG] for skin antisepsis, use of coated catheters), socio-adaptive interventions (eg, feedback of CLABSI rates, use of appropriateness criteria), and leadership support for CLABSI prevention.

RESULTS

Survey response rate was 47% (415/881). Technical interventions such as maximal sterile barriers (99%) or CHG-impregnated dressings (92%) were highly prevalent, but routine use of CHG bathing was less common (68% indicated regular use in intensive care unit [ICU] vs 18% in non-ICU settings). Although 97% of respondents indicated use of systems to monitor CLABSI, feedback to providers on CLABSI events was reported by 89%. Only 53% of respondents indicated regular use of tools to determine appropriateness of central venous catheters (CVC). Three-quarters of respondents indicated their hospital assessed CVC necessity daily, but only 23% reported strategies to reduce routine blood cultures. CLABSI prevention was extremely important to hospital leadership at 82% of responding hospitals.

CONCLUSIONS

Most US hospitals continue to use evidence-based methods to prevent CLABSI as recommended by leading organizations. Opportunities to focus on socio-adaptive interventions such as feedback of infection rates, use of appropriateness criteria for CVC placement, and improving the "culture of pan-culturing" remain.

Efficacy of Lysostaphin functionalized silicon catheter for the prevention of Staphylococcus aureus biofilm

Staphylococcus aureus readily forms biofilms on tissue and indwelling catheter surfaces. These biofilms are resistant to antibiotics. Consequently, effective prevention and treatment strategies against staphylococcal biofilms are actively being pursued over the past two decades. One of the proposed strategies involve the incorporation of antibiotics and antiseptics into catheters, however, a persistent concern regarding the possible emergence of antimicrobial resistance is associated with these medical devices. In this study, we developed two types of silicone catheters: one with Lysostaphin (Lst) adsorbed onto the surface, and the other with Lst functionalized on the surface. To confirm the presence of Lst protein on the catheter surface, we conducted FTIR-ATR and SEM-EDS analysis. Both catheters exhibited hemocompatibility, biocompatibility, and demonstrated antimicrobial and biofilm prevention activities against both methicillin-sensitive and resistant strains of S. aureus. Furthermore, the silicone catheters that were surface-functionalized with Lst showed substantially better and more persistent anti-biofilm effects when compared to the catheters where Lst was surface-adsorbed, both under in vitro static and flow conditions, as well as in vivo in BALB/c mice. These results indicate that surface-functionalized Lst catheters have the potential to serve as a promising new medical device for preventing S. aureus biofilm infections in humans.

Efficacy of antimicrobial peripherally inserted central catheters in line-associated bloodstream infections: A systematic review and meta-analysis

BACKGROUND

Several studies have investigated the safety and efficacy of antimicrobial peripherally inserted central catheters (PICCs), and the results are conflicting. Therefore, in this systematic review and meta-analysis, we aimed to summarize and identify the effect of antimicrobial PICCs on central line-associated bloodstream infection (CLABSI) risk.

METHODS

A systematic search of PubMed, Ovid MEDLINE, Ovid Embase, and Web of Science was performed to identify relevant studies up to December 2022.

RESULTS

A total of 9 studies were included for analysis. There were 7 retrospective/prospective cohort studies and 2 randomized controlled trials. The 9 studies involved 51,373 patients with PICCs. Among these patients, 6,563 (12.8%) antimicrobial-coated/impregnated PICCs and 44,810 (87.2%) nonantimicrobial-impregnated PICCs were inserted. The meta-analysis showed that antimicrobial PICCs had a nonsignificant association with lower CLABSI risk compared with noncoated PICCs (relative risk [RR] = 0.67; 95% CI, 0.43-1.05). In the subgroup analysis, minocycline-rifampin-(RR = 0.30; 95% CI, 0.19-0.49) or chlorhexidine-coated (RR = 0.61; 95% CI, 0.04-8.55) PICCs showed an association with reduced risk of CLABSI. In the adult population, antimicrobial PICCs had a nonsignificant association with lower CLABSI risk (RR = 0.50; 95% CI, 0.20-1.22).

CONCLUSIONS

This systematic review and meta-analysis suggested that antimicrobial PICCs had a nonsignificant association with lower CLABSI risk compared with noncoated PICCs. Minocycline-rifampin-or chlorhexidine-coated PICCs showed an association with reduced risk of CLABSI.

A New In Vitro Blood Flow Model for the Realistic Evaluation of Antimicrobial Surfaces

Device-associated bloodstream infections can cause serious medical problems and cost-intensive postinfection management, defining a need for more effective antimicrobial coatings. Newly developed coatings often show reduced bacterial colonization and high hemocompatibility in established in vitro tests, but fail in animal studies or clinical trials. The poor predictive power of these models is attributed to inadequate representation of in vivo conditions. Herein, a new single-pass blood flow model, with simultaneous incubation of the test surface with bacteria and freshly-drawn human blood, is presented. The flow model is validated by comparative analysis of a recently developed set of antiadhesive and contact-killing polymer coatings, and the corresponding uncoated polycarbonate surfaces. The results confirm the model's ability to differentiate the antimicrobial activities of the studied surfaces. Blood activation data correlate with bacterial surface coverage: low bacterial adhesion is associated with low inflammation and hemostasis. Shear stress correlates inversely with bacterial colonization, especially on antiadhesive surfaces. The introduced model is concluded to enable the evaluation of novel antimicrobial materials under in vivo-like conditions, capturing interactions between bacteria and biomaterials surfaces in the presence of key components of the ex vivo host response.

Biosurfactant from Nile Papyrus endophyte with potential antibiofilm activity against global clones of Acinetobacter baumannii

Acinetobacter baumannii is a leading cause of biofilm-associated infections, particularly catheter-related bloodstream infections (CRBSIs) that are mostly recalcitrant to antimicrobial therapy. One approach to reducing the burden of CRBSIs is inhibiting biofilm formation on catheters. Owing to their prodigious microbial diversity, bacterial endophytes might be a valuable source of biosurfactants, which are known for their great capacity to disperse microbial biofilms. With this in mind, our study aimed to screen bacterial endophytes from plants growing on the banks of the River Nile for the production of powerful biosurfactants capable of reducing the ability of A. baumannii to form biofilms on central venous catheters (CVCs). This was tested on multidrug- and extensive drug-resistant (M/XDR) clinical isolates of A. baumannii that belong to high-risk global clones and on a standard strain of A. baumannii ATCC 19606. The drop collapse and oil dispersion assays were employed in screening the cell-free supernatants (CFS) of all endophytes for biosurfactant activity. Of the 44 bacterial endophytes recovered from 10 plants, the CFS of Bacillus amyloliquefaciens Cp24, isolated from Cyperus papyrus, showed the highest biosurfactant activity. The crude biosurfactant extract of Cp24 showed potent antibacterial activity with minimum inhibitory concentrations (MICs) ranging from 0.78 to 1.56 mg/ml. It also showed significant antibiofilm activity (p-value<0.01). Sub-MICs of the extract could reduce biofilm formation by up to 89.59%, while up to 87.3% of the preformed biofilms were eradicated by the MIC. A significant reduction in biofilm formation on CVCs impregnated with sub-MIC of the extract was demonstrated by CV assay and further confirmed by scanning electron microscopy. This was associated with three log₁₀ reductions in adhered bacteria in the viable count assay. GC-MS analysis of the crude biosurfactant extract revealed the presence of several compounds, such as saturated, unsaturated, and epoxy fatty acids, cyclopeptides, and 3-Benzyl-hexahydro-pyrrolo [1, 2-a] pyrazine-1,4-dione, potentially implicated in the potent biosurfactant and antibiofilm activities. In the present study, we report the isolation of a B. amyloliquefaciens endophyte from the plant C. papyrus that produces a biosurfactant with potent antibiofilm activity against MDR/XDR global clones of A. baumannii. The impregnation of CVCs with the biosurfactant was demonstrated to reduce biofilms and, hence, proposed as a potential strategy for reducing CRBSIs.

Auranofin coated catheters inhibit bacterial and fungal biofilms in a murine subcutaneous model

Microbe entry through catheter ports can lead to biofilm accumulation and complications from catheter-related bloodstream infection and ultimately require antimicrobial treatment and catheter replacement. Although strides have been made with microbial prevention by applying standardized antiseptic techniques during catheter implantation, both bacterial and fungal microbes can present health risks to already sick individuals. To reduce microbial adhesion, murine and human catheters were coated with polyurethane and auranofin using a dip coating method and compared to non-coated materials. Upon passage of fluid through the coated material in vitro, flow dynamics were not impacted. The unique antimicrobial properties of the coating material auranofin has shown inhibitory activity against bacteria such as Staphylococcus aureus and fungi such as Candida albicans. Auranofin coating on catheters at 10mg/mL reduced C. albicans accumulation in vitro from 2.0 x 10⁸ to 7.8 x 10⁵ CFU for mouse catheters and from 1.6 x 10⁷ to 2.8 x 10⁶ for human catheters, showing an impact to mature biofilms. Assessment of a dual microbe biofilm on auranofin-coated catheters resulted in a 2-log reduction in S. aureus and a 3-log reduction in C. albicans compared to uncoated catheters. In vivo assessment in a murine subcutaneous model demonstrated that catheters coated with 10 mg/mL auranofin reduced independent S. aureus and C. albicans accumulation by 4-log and 1-log, respectively, compared to non-coated catheters. In conclusion, the auranofin-coated catheters demonstrate proficiency at inhibiting multiple pathogens by decreasing S. aureus and C. albicans biofilm accumulation.

Antimicrobial materials for endotracheal tubes: A review on the last two decades of technological progress

Ventilator-associated pneumonia (VAP) is an unresolved problem in nosocomial settings, remaining consistently associated with a lack of treatment, high mortality, and prolonged hospital stay. The endotracheal tube (ETT) is the major culprit for VAP development owing to its early surface microbial colonization and biofilm formation by multiple pathogens, both critical events for VAP pathogenesis and relapses. To combat this matter, gradual research on antimicrobial ETT surface coating/modification approaches has been made. This review provides an overview of the relevance and implications of the ETT bioburden for VAP pathogenesis and how technological research on antimicrobial materials for ETTs has evolved. Firstly, certain main VAP attributes (definition/categorization; outcomes; economic impact) were outlined, highlighting the issues in defining/diagnosing VAP that often difficult VAP early- and late-onset differentiation, and that generate misinterpretations in VAP surveillance and discrepant outcomes. The central role of the ETT microbial colonization and subsequent biofilm formation as fundamental contributors to VAP pathogenesis was then underscored, in parallel with the uncovering of the polymicrobial ecosystem of VAP-related infections. Secondly, the latest technological developments (reported since 2002) on materials able to endow the ETT surface with active antimicrobial and/or passive antifouling properties were annotated, being further subject to critical scrutiny concerning their potentialities and/or constraints in reducing ETT bioburden and the risk of VAP while retaining/improving the safety of use. Taking those gaps/challenges into consideration, we discussed potential avenues that may assist upcoming advances in the field to tackle VAP rampant rates and improve patient care. STATEMENT OF SIGNIFICANCE: The use of the endotracheal tube (ETT) in patients requiring mechanical ventilation is associated with the development of ventilator-associated pneumonia (VAP). Its rapid surface colonization and biofilm formation are critical events for VAP pathogenesis and relapses. This review provides a comprehensive overview on the relevance/implications of the ETT biofilm in VAP, and on how research on antimicrobial ETT surface coating/modification technology has evolved over the last two decades. Despite significant technological advances, the limited number of gathered reports (46), highlights difficulty in overcoming certain hurdles associated with VAP (e.g., persistent colonization/biofilm formation; mechanical ventilation duration; hospital length of stay; VAP occurrence), which makes this an evolving, complex, and challenging matter. Challenges and opportunities in the field are discussed.

Management of long-term home parenteral nutrition: Historical perspective, common complications, and patient education and training

Intestinal failure (IF) is a rare disease that requires ongoing intravenous supplementation to sustain growth and health. Advancements in parenteral nutrition (PN) and central venous access in the 1960s and 1970s transformed a life-limiting disease to a chronic one in which patients are able to administer hydration, electrolytes, micronutrients, and macronutrients in the comfort of their home. However, despite ongoing advancements in the field of home PN (HPN), complications-whether related to central venous catheters or PN itself-remain common and can be associated with significant morbidity and mortality. Central venous access can be associated with thrombosis, central line-associated bloodstream infection, or damage and can result in loss of access over time. PN can be associated with IF-associated liver disease or hyperglycemia. The key to preserving central venous access and quality of life and maintaining health for patients with chronic IF (CIF) is education focused on prevention and prompt management of CIF complications as they arise. This education typically takes place at the time of initiation of HPN, either in the hospital setting or in the patient's home. The present manuscript describes the historical progression of HPN, prevalence and characteristics of CIF, and an in-depth discussion of the most common catheter-related and PN-related complications and their management, along with a discussion of our education and training process.

Phyto-assisted synthesis of zinc oxide nanoparticles for developing antibiofilm surface coatings on central venous catheters

Medical devices such as Central Venous Catheters (CVCs), are routinely used in intensive and critical care settings. In the present scenario, incidences of Catheter-Related Blood Stream Infections (CRBSIs) pose a serious challenge. Despite considerable advancements in the antimicrobial therapy and material design of CVCs, clinicians continue to struggle with infection-related complications. These complications are often due colonization of bacteria on the surface of the medical devices, termed as biofilms, leading to infections. Biofilm formation is recognized as a critical virulence trait rendering infections chronic and difficult to treat even with 1,000x, the minimum inhibitory concentration (MIC) of antibiotics. Therefore, non-antibiotic-based solutions that prevent bacterial adhesion on medical devices are warranted. In our study, we report a novel and simple method to synthesize zinc oxide (ZnO) nanoparticles using ethanolic plant extracts of Eupatorium odoratum. We investigated its physio-chemical characteristics using Field Emission- Scanning Electron Microscopy and Energy dispersive X-Ray analysis, X-Ray Diffraction (XRD), Photoluminescence Spectroscopy, UV-Visible and Diffuse Reflectance spectroscopy, and Dynamic Light Scattering characterization methods. Hexagonal phase with wurtzite structure was confirmed using XRD with particle size of ∼50 nm. ZnO nanoparticles showed a band gap 3.25 eV. Photoluminescence spectra showed prominent peak corresponding to defects formed in the synthesized ZnO nanoparticles. Clinically relevant bacterial strains, viz., Proteus aeruginosa PAO1, Escherichia coli MTCC 119 and Staphylococcus aureus MTCC 7443 were treated with different concentrations of ZnO NPs. A concentration dependent increase in killing efficacy was observed with 99.99% killing at 500 μg/mL. Further, we coated the commercial CVCs using green synthesized ZnO NPs and evaluated it is in vitro antibiofilm efficacy using previously optimized in situ continuous flow model. The hydrophilic functionalized interface of CVC prevents biofilm formation by P. aeruginosa, E. coli and S. aureus. Based on our findings, we propose ZnO nanoparticles as a promising non-antibiotic-based preventive solutions to reduce the risk of central venous catheter-associated infections.

Recent Developments in Multifunctional Antimicrobial Surfaces and Applications toward Advanced Nitric Oxide-Based Biomaterials

Implant-associated infections arising from biofilm development are known to have detrimental effects with compromised quality of life for the patients, implying a progressing issue in healthcare. It has been a struggle for more than 50 years for the biomaterials field to achieve long-term success of medical implants by discouraging bacterial and protein adhesion without adversely affecting the surrounding tissue and cell functions. However, the rate of infections associated with medical devices is continuously escalating because of the intricate nature of bacterial biofilms, antibiotic resistance, and the lack of ability of monofunctional antibacterial materials to prevent the colonization of bacteria on the device surface. For this reason, many current strategies are focused on the development of novel antibacterial surfaces with dual antimicrobial functionality. These surfaces are based on the combination of two components into one system that can eradicate attached bacteria (antibiotics, peptides, nitric oxide, ammonium salts, light, etc.) and also resist or release adhesion of bacteria (hydrophilic polymers, zwitterionic, antiadhesive, topography, bioinspired surfaces, etc.). This review aims to outline the progress made in the field of biomedical engineering and biomaterials for the development of multifunctional antibacterial biomedical devices. Additionally, principles for material design and fabrication are highlighted using characteristic examples, with a special focus on combinational nitric oxide-releasing biomedical interfaces. A brief perspective on future research directions for engineering of dual-function antibacterial surfaces is also presented.

[Update of the recommendations of the Bacteraemia Zero Project]

El proyecto Bacteriemia Zero (BZ) fue el primero de los Proyectos Zero que se implementó en las Unidades de Cuidados Intensivos (UCI), consiguiendo una disminución de las tasas de infección relacionadas con catéter por debajo de las recomendadas por los estándares de calidad de las sociedades científicas. A raíz de la pandemia causada por el SARS-CoV-2 en las UCI, se ha observado un incremento importante de estas tasas de infección. El incremento de las tasas de infección y la necesidad de incorporar en la práctica clínica la mejor evidencia disponible, justifica la necesidad de actualizar las recomendaciones del proyecto BZ. Se constituyó un grupo de trabajo formado por miembros de las diferentes sociedades científicas que consideró que el paquete de medidas obligatorias del proyecto no debía modificarse debido a su eficacia demostrada y decidió incorporar, después de su revisión, las siguientes medidas opcionales: uso de catéteres impregnados con antimicrobianos, uso de apósitos impregnados con clorhexidina, uso de tapones con solución antiséptica en los conectores e higiene corporal diaria con clorhexidina.

Blood compatibility of widely used central venous catheters; an experimental study

An inserted central venous catheter (CVC) is considered foreign material by the inert host defence systems and induce inflammation and thrombus formation. The objective of this study was to evaluate blood compatibility of six commonly used CVCs. Three coated and three uncoated CVC materials were tested in a modified Chandler loop model. Each catheter material circulated in blood from ten different healthy volunteers for 1 h. Blood cell counts and measurements of the inert host defence systems were performed on blood samples from the loop. All the tested catheters demonstrated impact on blood cells, contact coagulation, the complement system, or inflammatory markers, although the impact varied significantly. Of the catheters we evaluated, the most unfavourable blood compatibility profile was found for the polyurethane CVC coated with chlorohexidine and silver sulfadiazine. The greatest variation in blood compatibility between test runs was noted for the silicone dialysis catheter. Poor blood compatibility should be taken seriously but given the experimental design of the current study the clinical significance remains to be evaluated.

Prevention of medical device infections via multi-action nitric oxide and chlorhexidine diacetate releasing medical grade silicone biointerfaces

The presence of bacteria and biofilm on medical device surfaces has been linked to serious infections, increased health care costs, and failure of medical devices. Therefore, antimicrobial biointerfaces and medical devices that can thwart microbial attachment and biofilm formation are urgently needed. Both nitric oxide (NO) and chlorhexidine diacetate (CHXD) possess broad-spectrum antibacterial properties. In the past, individual polymer release systems of CHXD and NO donor S-nitroso-N-acetylpenicillamine (SNAP) incorporated polymer platforms have attracted considerable attention for biomedical/therapeutic applications. However, the combination of the two surfaces has not yet been explored. Herein, the synergy of NO and CHXD was evaluated to create an antimicrobial medical-grade silicone rubber. The 10 wt% SNAP films were fabricated using solvent casting with a topcoat of CHXD (1, 3, and 5 wt%) to generate a dual-active antibacterial interface. Chemiluminescence studies confirmed the NO release from SNAP-CHXD films at physiologically relevant levels (0.5-4 × 10^-10  mol min^-1  cm^-2 ) for at least 3 weeks and CHXD release for at least 7 days. Further characterization of the films via SEM-EDS confirmed uniform distribution of SNAP and presence of CHXD within the polymer films without substantial morphological changes, as confirmed by contact angle hysteresis. Moreover, the dual-active SNAP-CHXD films were able to significantly reduce Escherichia coli and Staphylococcus aureus bacteria (>3-log reduction) compared to controls with no explicit toxicity towards mouse fibroblast cells. The synergy between the two potent antimicrobial agents will help combat bacterial contamination on biointerfaces and enhance the longevity of medical devices.

Synthesis, Characterization and Biomedical Application of Silver Nanoparticles

Silver nanoparticles (AgNPs) have been employed in various fields of biotechnology due to their proven properties as an antibacterial, antiviral and antifungal agent. AgNPs are generally synthesized through chemical, physical and biological approaches involving a myriad of methods. As each approach confers unique advantages and challenges, a trends analysis of literature for the AgNPs synthesis using different types of synthesis were also reviewed through a bibliometric approach. A sum of 10,278 publications were analyzed on the annual numbers of publication relating to AgNPs and biological, chemical or physical synthesis from 2010 to 2020 using Microsoft Excel applied to the Scopus publication database. Furthermore, another bibliometric clustering and mapping software were used to study the occurrences of author keywords on the biomedical applications of biosynthesized AgNPs and a total collection of 224 documents were found, sourced from articles, reviews, book chapters, conference papers and reviews. AgNPs provides an excellent, dependable, and effective solution for seven major concerns: as antibacterial, antiviral, anticancer, bone healing, bone cement, dental applications and wound healing. In recent years, AgNPs have been employed in biomedical sector due to their antibacterial, antiviral and anticancer properties. This review discussed on the types of synthesis, how AgNPs are characterized and their applications in biomedical field.

Does the antimicrobial-impregnated peripherally inserted central catheter decrease the CLABSI rate in neonates? Results from a retrospective cohort study

BACKGROUND

The use of antimicrobial-impregnated peripherally inserted central catheters (PICCs) has been introduced in the last few years to neonatal units aiming to reduce central line-associated bloodstream infection (CLABSI).

METHODS

This retrospective observational study aimed to compare the CLABSI rates and other catheter-related parameters including the insertion success rates and catheter-related complications in the antimicrobial-impregnated and conventional (ordinary) PICCs in NICU between 2017 and 2020.

RESULTS

Our dedicated PICC team including physicians and nurses inserted 1,242 conventional (PremiCath and NutriLine) and 791 antimicrobial-impregnated PICCs (PremiStar) over the study period from 2017 to 2020. Of those 1,242 conventional PICCs, 1,171 (94.3%) were 1 Fr single lumen and only 71 (5.7%) were 2 Fr double lumen. The mean ± SD [median (IQR)] for the birth weight in all babies who had a PICC line was 1,343.3 ± 686.75 [1,200 (900, 1,500)] g, while the mean ± SD for the gestational age was 29.6 ± 4.03 [29 (27, 31)] weeks. The mean ± SD [median (IQR)] age at the time of insertion for all catheters was 9.3 ± 21.47 [2 (1, 9)] days, while the mean ± SD [median (IQR)] dwell time was 15.7 ± 14.03 [12 (8, 17)] days. The overall success rate of the PICC insertion is 1,815/2,033 (89.3%), while the first attempt success rate is 1,290/2,033 (63.5%). The mean ± SD [median (IQR)] gestational age, birth weight, age at catheter insertion, and catheter dwell time were 28.8 ± 3.24 [29, (26, 31)] weeks, 1,192.1 ± 410.3 [1,150, (900, 1,450)] g, 6.3 ± 10.85 [2, (1, 8)] days, and 17.73 ± 17.532 [13, (9, 18)] days in the antimicrobial-impregnated catheter compared with 30.1 ± 4.39 [29, (27, 32)] weeks (P < 0.001), 1,439.5 ± 800.8 [1,240, (920, 1,520)] g (P < 0.001), 11.1 ± 25.9 [1, (1, 9)] days (P < 0.001), and 14.30 ± 10.964 [12, (8, 17)] days (P < 0.001), respectively, in the conventional PICCs. The use of the antimicrobial-impregnated catheter was not associated with any significant reduction in the CLABSI rate (per 1,000 days dwell time), either the overall [P = 0.11, risk ratio (RR) (95% CI): 0.60 (0.32, 1.13)] or the yearly CLABSI rates.

CONCLUSIONS

The use of miconazole and rifampicin-impregnated PICCs did not reduce the CLABSI rate in neonates compared with conventional PICCs. However, it has a higher overall rate of elective removal after completion of therapy and less extravasation/infiltration, occlusion, and phlebitis compared with the conventional PICCs. Further large RCTs are recommended to enrich the current paucity of evidence and to reduce the risk of bias. Neonatal PICCs impregnation by other antimicrobials is a recommendation for vascular access device manufacturers.

Effectiveness of Impregnated Central Venous Catheters on Catheter-Related Bloodstream Infection in Pediatrics

BACKGROUND

The efficacy and safety of impregnated central venous catheters (CVCs) in pediatrics remain controversial. The purpose of this study was to evaluate the efficacy of impregnations for the prevention of catheter-related bloodstream infection (CRBSI).

METHODS

We searched the following five electronic databases: Medline, PubMed, Cochrane, Embase, and the Web of Science for randomized controlled trials (RCTs) up to March 2021. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using a fixed-effects model. Assessment of publication biases was evaluated by Egger's test. Heterogeneity between studies was assessed based on the chi-square test and I ² statistics, and sensitivity analysis and subgroup analysis were also performed.

RESULTS

A total of six RCTs with 3,091 patients were included. Impregnated CVCs provided significant benefits in reducing the risk of CRBSI (RR = 0.41, 95% CI: 0.26-0.66) in pediatric patients, especially in the pediatric group. No publication bias was observed in the Egger test for the risk of CRBSI. Drug type is a source of heterogeneity.

CONCLUSION

Antimicrobial-impregnated CVCs are beneficial to prevent CVC-related complications in pediatrics.

The prospects of antimicrobial coated medical implants

The implants are increasingly being a part of modern medicine in various surgical procedures for functional or cosmetic purposes. The progressive use of implants is associated with increased infectious complications and prevention of such infections always remains precedence in the clinical settings. The preventive approaches include the systemic administration of antimicrobial agents before and after the surgical procedures as well as the local application of antibiotics. The relevant literature and existing clinical practices have highlighted the role of antimicrobial coating approaches in the prevention of implants associated infections, although the applications of these strategies are not yet standardized, and the clinical efficacy is not much clear. The adequate data from the randomized control trials is challenging because of the unavailability of a large sample size although it is compulsory in this context to assess the clinical efficacy of preemptive practices. This review compares the efficacy of preventive approaches and the prospects of antimicrobial-coated implants in preventing implant-related infections.

What is new in catheter use and catheter infection prevention in the ICU

PURPOSE OF REVIEW

Short-term intravascular catheters are instrumental in the care of critically ill patients. Despite their benefits, they also are potential entries for systemic infections. There is a growing body of literature on catheter use and the prevention of intravascular catheter infections in intensive care. This review highlights major recent contributions to the topic and put them into perspective to recommendations on best practice procedures.

RECENT FINDINGS

Many studies published in the last years have evaluated prevention strategies applying technology and addressing behavior change. Skin disinfection with 2% alcoholic chlorhexidine-gluconate (CHG) and CHG-impregnated dressings are increasingly used in clinical practice. However, the role of universal CHG bathing remains controversial. A number of new and innovative technologies are in development. Recent qualitative research offers new perspectives about behavior change interventions to improve implementation.

SUMMARY

Many options for effective intravascular catheter infection prevention are currently available. A number of recent systematic reviews and meta-analyses not only confirmed measures targeting best practice and technology at catheter insertion and catheter care but also challenged interventions, such as CHG bathing. More focus should be put to implementation strategies.

Efficacy of Antimicrobial-Impregnated Catheters for Prevention of Bloodstream Infections in Pediatric Patients: A Meta-Analysis

Background: Multiple Randomized controlled trials (RCTs) have evaluated the efficacy of antimicrobial-impregnated catheters to prevent catheter-related bloodstream infections (CRBSI). However, the RCTs showed contradictory results, the studies were limited in sample size and methodology quality. Thus, we conducted a meta-analysis to overcome these RCT limitations. Methods: We designed a meta-analysis of RCTs comparing antimicrobial-impregnated and conventional catheters for the prevention of CRBSI. We conducted a detailed search of various databases for RCTs published before November 2019. We calculated mean differences (MDs) and pooled odds ratios (ORs) with 95% confidence intervals (CIs) using a random-effects model. Results: We included five RCTs with a total of 2,294 patients. The incidence of CRBSI between the two groups was 0.50 (95% CI, 0.19-1.27), with evidence of heterogeneity (I ² = 55%). The difference was not statistically significant (p = 0.15). On subgroup analysis based on the age of the sample, there was no difference in the rate of CRBSI in the neonatal population [0.42 (95% CI, 0.08-2.27 I ² = 61% p = 0.31] as well as pediatric population [0.45 (95% CI, 0.12-1.67 I ² = 39% p = 0.23]. The summary OR on the incidence of catheter colonization between antimicrobial-impregnated and conventional catheters was 0.64 (95% CI, 0.17-2.35), with no evidence of heterogeneity (I ² = 0%) and a non-significant difference (p = 0.50). Conclusions: To conclude, analysis of a limited number of heterogeneous studies mostly with a small sample indicates that the CRBSI and catheter colonization rates are similar between conventional and antimicrobial-impregnated catheters in the pediatric and neonatal population. There is an urgent need for large-scale RCTs focusing on different antimicrobial-impregnated catheters in these patients to further enhance current evidence.

Central venous catheter insertion: Review of recent evidence

Guidelines for prevention of catheter-related bloodstream infection (CR-BSI) describe a series of recommendations for correct insertion and handling of central venous catheters (CVCs). Since their implementation, quality programs such as "Zero bacteremia" have achieved a reduction in CR-BSI rates, but there is still room for further improvement. New evidence is emerging regarding, e.g., antiseptic-antimicrobial impregnated catheters or the use of passive disinfection of closed connectors. These examples of new tools among others might help to further decrease infection rates. This article aims to review new evidence-based strategies to reduce catheter insertion-related infection.

Doxycycline-Coated Silicone Breast Implants Reduce Acute Surgical-Site Infection and Inflammation

BACKGROUND

Surgical-site infection after implant-based breast reconstruction remains a leading cause of morbidity. Doxycycline is an antibiotic used to treat soft-tissue infections. The authors hypothesize that doxycycline-coated breast implants will significantly reduce biofilm formation, surgical-site infection, and inflammation after bacterial infection.

METHODS

Pieces of silicone breast implants were coated in doxycycline. In vitro studies to characterize the coating include Fourier transmission infrared spectroscopy, elution data, and toxicity assays (n = 4). To evaluate antimicrobial properties, coated implants were studied after methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa inoculation in vitro and in a mouse model at 3 and 7 days (n = 8). Studies included bacterial quantification, cytokine profiles, and histology.

RESULTS

Coated silicone breast implants demonstrated a color change, increased mass, and Fourier transmission infrared spectroscopy consistent with a doxycycline coating. Coated implants were nontoxic to fibroblasts and inhibited biofilm formation and bacterial adherence after MRSA and P. aeruginosa incubation in vitro, and measurable doxycycline concentrations at 24 hours were seen. In a mouse model, a significant reduction of MRSA and P. aeruginosa bacterial colonization after 3 and 7 days in the doxycycline-coated implant mice was demonstrated when compared to the control mice, control mice treated with intraperitoneal doxycycline, and control mice treated with a gentamicin/cefazolin/bacitracin wash. Decreased inflammatory cytokines and inflammatory cell infiltration were demonstrated in the doxycycline-coated mice.

CONCLUSIONS

A method to coat silicone implants with doxycycline was developed. The authors' doxycycline-coated silicone implants significantly reduced biofilm formation, surgical-site infections, and inflammation. Further studies are needed to evaluate the long-term implications.

Inhibition of Mixed Biofilms of Candida albicans and Methicillin-Resistant Staphylococcus aureus by Positively Charged Silver Nanoparticles and Functionalized Silicone Elastomers

Both bacterial and fungal organisms display the ability to form biofilms; however, mixed bacterial/fungal biofilms are particularly difficult to control and eradicate. The opportunistic microbial pathogens Candida albicans and Staphylococcus aureus are among the most frequent causative agents of healthcare-acquired infections, and are often co-isolated forming mixed biofilms, especially from contaminated catheters. These mixed species biofilms display a high level of antibiotic resistance; thus, these infections are challenging to treat resulting in excess morbidity and mortality. In the absence of effective conventional antibiotic treatments, nanotechnology-based approaches represent a promising alternative for the treatment of highly recalcitrant polymicrobial biofilm infections. Our group has previously reported on the activity of pure positively charged silver nanoparticles synthesized by a novel microwave technique against single-species biofilms of C. albicans and S. aureus. Here, we have expanded our observations to demonstrate that that silver nanoparticles display dose-dependent activity against dual-species C. albicans/S. aureus biofilms. Moreover, the same nanoparticles were used to functionalize catheter materials, leading to the effective inhibition of the mixed fungal/bacterial biofilms. Overall, our results indicate the potent activity of silver nanoparticles against these cross-kingdom biofilms. More studies are warranted to examine the ability of functionalized catheters in the prevention of catheter-related bloodstream infections.

Central venous catheter insertion and maintenance: Evidence-based clinical recommendations

OBJECTIVE

To share with clinicians supporting evidence of the safest and the most effective processes for central venous catheter insertion and maintenance as a strategy to prevent catheter-associated bloodstream infections.

METHODS

A literature search was conducted in the Medline via PubMed, Embase Central and Lilacs databases based on a set of clinical questions aimed at improving safety and effectiveness at key moments in the process of central venous catheter insertion and maintenance. The rapid literature review methodology was used. The studies identified were assessed from the quality point of view, using the Joanna Briggs Institute (JBI) tools for qualitative and quantitative studies and for systematic reviews. Clinical practice guidelines were assessed using the AGREE II tool. The evidence is presented in the form of evidence-based clinical recommendations, which were graded in accordance with the JBI methodology.

RESULTS

Twelve clinical evidence summaries containing evidence related to the safe and effective use of central venous catheters are presented, including the following topics: central venous catheter insertion (CVC), peripherally inserted central catheters (PICC), preoperative assessment, the use of analgesia, field preparation, choice between CVC or PICC, CVC care and maintenance, prevention of complications, and general considerations pertaining to the use of central venous catheters in oncologic patients and in parenteral nutrition.

CONCLUSIONS

Recommendations on the safe and effective use of central venous access catheters in relation to CVC insertion and maintenance processes are presented in the evidence-based summary model. It is necessary to evaluate their implementation in health outcomes in the institutions where they are developed.

Long-term vascular access in differently resourced settings: a review of indications, devices, techniques, and complications

Central venous access is frequently essential for the management of many acute and chronic conditions in children. Millions of central venous access devices (CVADs) are placed each year. In this review article, we discuss the indications for long-term vascular access, the types of devices available, the state of the art of central venous cannulation and device placement, and the complications of long-term central venous access. We pay a special attention to the challenges of, and options for long-term central venous access, also those in developing countries, with limited financial, human, and material resources.

Dibasic Derivatives of Phenylcarbamic Acid as Prospective Antibacterial Agents Interacting with Cytoplasmic Membrane

1-[2-[({[2-/3-(Alkoxy)phenyl]amino}carbonyl)oxy]-3-(dipropylammonio)propyl]pyrrolidinium/azepan- ium oxalates or dichlorides (alkoxy = butoxy to heptyloxy) were recently described as very promising antimycobacterial agents. These compounds were tested in vitro against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 (reference and control strains), three methicillin-resistant isolates of S. aureus, and three isolates of vancomycin-resistant E. faecalis. 1-[3-(Dipropylammonio)-2-({[3-(pentyloxy-/hexyloxy-/heptyloxy)phenyl]carbamoyl}oxy)propyl]pyrrolidinium dichlorides showed high activity against staphylococci and enterococci comparable with or higher than that of used controls (clinically used antibiotics and antiseptics). The screening of the cytotoxicity of the compounds as well as the used controls was performed using human monocytic leukemia cells. IC50 values of the most effective compounds ranged from ca. 3.5 to 6.3 µM, thus, it can be stated that the antimicrobial effect is closely connected with their cytotoxicity. The antibacterial activity is based on the surface activity of the compounds that are influenced by the length of their alkoxy side chain, the size of the azacyclic system, and hydro-lipophilic properties, as proven by in vitro experiments and chemometric principal component analyses. Synergistic studies showed the increased activity of oxacillin, gentamicin, and vancomycin, which could be explained by the direct activity of the compounds against the bacterial cell wall. All these compounds demonstrate excellent antibiofilm activity, when they inhibit and disrupt the biofilm of S. aureus in concentrations close to minimum inhibitory concentrations against planktonic cells. Expected interactions of the compounds with the cytoplasmic membrane are proven by in vitro crystal violet uptake assays.

Deciphering the Mechanisms of Bacterial Inactivation on HiPIMS Sputtered CuxO-FeOx-PET Surfaces: From Light Absorption to Catalytic Bacterial Death

The production of nontoxic, affordable, and efficient antibacterial surfaces is key to the well-being of our societies. In this aim, antibacterial thin films have been prepared using earth-abundant metals deposited using high-power impulse magnetron sputtering (HiPIMS). The sputtered FeO_x, Cu_xO, and mixed Cu_xO-FeO_x films exhibited fast bacterial inactivation properties under exposure to indoor light (340-720 nm) showing total bacterial inactivation within 180, 120, and 60 min, respectively. The photocatalytic mechanisms of these films were investigated, from the absorption of photons up to the bacteria's fate, by means of ultrafast transient spectroscopy, flow cytometry, and malondialdehyde (MDA) quantification justifying the cell wall disruption. The primary driving force leading to bacterial inactivation was found to be the oxidative stress at the interface between the sputtered thin films and the microorganism. This was justified by using engineered porinless bacteria disabling the possible ion diffusion leading to internal bacterial inactivation. Such stress is a direct consequence of the photogenerated electron-hole pairs at the interface of the sputtered layers. By diffuse reflectance spectroscopy, we found that both FeO_x and Cu_xO present a band gap of ∼2.9 eV (>425 nm), while the mixed Cu_xO-FeO_x thin film has a band gap below 2.3 eV (>540 nm). The structure and atomic composition of the films were characterized by energy-dispersive X-ray, X-ray photoelectron, and optical spectroscopy. While the composition and metal oxidation states are distinct in all three films, the difference in photocatalytic efficiency can, at first sight, be explained as the direct consequence of their absorbance and the unique interaction between Fe and Cu oxides in the composite film.

Central venous access device-related sheaths: a predictor of infective and thrombotic incidence?

Central vascular access device (CVAD)-related sheaths, sometimes described as ‘fibrin sheaths’, may result in minor or significant sequelae, from persistent withdrawal occlusion (PWO) to infective sheaths associated with increased morbidity and mortality. The authors studied 179 patients who underwent isotope scans, where isotope was infused via the CVAD. Isotope was found to bind to the sheaths around the catheters of some patients. The amount of uptake was taken to be an extent to which a sheath had developed around the CVAD. The degree of uptake of isotope was categorised into three groups: low uptake, moderate uptake and high uptake. Patients were then followed up from the date the CVAD was inserted to 12 months after the date of the isotope scan, until the device was removed or to the date the patient died, to identify incidence of infection, thrombosis and PWO. PWO incidence in all levels of uptake was around 5–7%. Bloodstream infection (BSI) incidence for low uptake was 7% (9/130), moderate uptake 10% (3/30) and for patients with significant uptake 16% (3/19). Thrombosis for no uptake was less than 1% (1/130), moderate uptake 7% (2/30), and significant uptake had no incidence of thrombosis. Total complications: no uptake 15%, moderate uptake 23% and significant uptake 21%. This single-centre study showed that patients with isotope-highlighted sheaths experienced higher incidence of infective, thrombotic and total complications.

Fused Deposition Modelling as a Potential Tool for Antimicrobial Dialysis Catheters Manufacturing: New Trends vs. Conventional Approaches

The rising rate of individuals with chronic kidney disease (CKD) and ineffective treatment methods for catheter-associated infections in dialysis patients has led to the need for a novel approach to the manufacturing of catheters. The current process requires moulding, which is time consuming, and coated catheters used currently increase the risk of bacterial resistance, toxicity, and added expense. Three-dimensional (3D) printing has gained a lot of attention in recent years and offers the opportunity to rapidly manufacture catheters, matched to patients through imaging and at a lower cost. Fused deposition modelling (FDM) in particular allows thermoplastic polymers to be printed into the desired devices from a model made using computer aided design (CAD). Limitations to FDM include the small range of thermoplastic polymers that are compatible with this form of printing and the high degradation temperature required for drugs to be extruded with the polymer. Hot-melt extrusion (HME) allows the potential for antimicrobial drugs to be added to the polymer to create catheters with antimicrobial activity, therefore being able to overcome the issue of increased rates of infection. This review will cover the area of dialysis and catheter-related infections, current manufacturing processes of catheters and methods to prevent infection, limitations of current processes of catheter manufacture, future directions into the manufacture of catheters, and how drugs can be incorporated into the polymers to help prevent infection.

In vitro activity of antimicrobial-impregnated catheters against biofilms formed by KPC-producing Klebsiella pneumoniae

AIM

To evaluate the activity and effectiveness of impregnated central venous catheters (CVC) against Klebsiella pneumoniae biofilms.

METHODS AND RESULTS

The antimicrobial activity and durability of impregnated-CVCs were evaluated over time and the size of zones of inhibition (ZI) was measured. Biofilm formation was observed by quantitative culture and also by scanning electron microscopy. The catheters impregnated with chlorhexidine/silver sulfadiazine (CHX/SS) reduced bacteria counts by 0·3 log and were most effective (P < 0·01) against Klebsiella pneumoniae biofilms N-acetylcysteine/levofloxacin (NAC/LEV) catheters. It was observed that the catheter impregnated with NAC/LEV had initially the largest average ZI size being statistically significant (P < 0·01). The NAC/LEV combination remained active until day 30, whereas the combination of CHX/SS was completely inactivated from day 15 on.

CONCLUSIONS

The NAC/LEV combination showed greater durability on the catheters, but it was the CHX/SS combination that had the greater initial efficacy in bacterial inhibition. It was also observed that NAC/LEV-impregnated catheters do not prevent the emergence of resistant subpopulations inside the inhibition halos during antimicrobial susceptibility tests.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results highlighted that the in vitro efficacy of antimicrobial-impregnated CVCs is limited by time and that their colonization occurred earlier than expected. Our data also demonstrated that NAC/LEV remained active until day 30 of evaluation and CHX/SS combination was completely inactivated from day 15 on. Our findings suggested that implantable devices should be carefully used by medical community.

The efficacy of a non-leaching antibacterial central venous catheter - a prospective, randomized, double-blind study

BACKGROUND

Antimicrobial coatings of central venous catheters (CVC) have the potential to reduce the risk of infectious complications. The aim of this study was to examine the efficacy of a catheter with a non-leaching antimicrobial coating against catheter colonization and bloodstream infections (BSI).

METHODS

The study was conducted in two centers using a prospective, randomized, double-blind and controlled design (680 intensive care patients; a protective CVC (Certofix® protect) or a standard CVC (Certofix®). Primary objectives were the rates of catheter colonization and BSI in the two groups. Other baseline demographics, APACHE II score, insertion site, location of CVC placement (ICU or theatre), indwelling time and length of ICU stay were comparable for both groups.

RESULTS

While the rate of catheter colonization between the coated and uncoated CVC (17.4% vs. 18.7%, P=0.7477) and the rate of microbiologically confirmed catheter associated infections were similar (1.4% vs. 1.9%, P=0.7521), the coated CVC showed a significantly lower incidence of BSI (2.0% vs. 6.5%, P=0.0081) and a significantly lower mean incidence of BSI per 1000 catheter days (3.2 vs. 8.3, P=0.0356).

CONCLUSION

The non-leaching antibacterial coating of the protective catheter was effective in reducing the incidence of BSI but not the rate of catheter colonization. However, the incidence of BSI is a better surrogate marker for the risk of developing clinical signs of infection suggesting that use of the non-leaching protective catheter is effective in this regard. Trial number: ClinicalTrials.gov (ID: NCT00555282), https://clinicaltrials.gov/show/NCT00555282.