Catheter-related bloodstream infections

How to administer an intravenous infusion using a gravity administration set or a volumetric pump

RATIONALE AND KEY POINTS

This article explains how to prepare and administer an intravenous (IV) infusion using a gravity administration (giving) set or a volumetric pump in a safe, effective manner. Nurses undertaking this procedure must ensure they have the knowledge and skills to do so and work within the limits of their competence. This article serves as a revision of best practice in administering IV infusions of fluids and medicines. • IV infusions are delivered directly into the bloodstream, so care must be taken to protect the patient from harm by following the appropriate policies and protocols and monitoring the patient carefully for adverse reactions. • There is a risk of administering large volumes of IV fluid to the patient when using a gravity administration set, so a burette or volumetric pump should be used in patients who may not tolerate this. • Volumetric pumps vary, so it is essential that the nurse is familiar with the device, uses the specific administration set required and follows the manufacturer's instructions. REFLECTIVE ACTIVITY: 'How to' articles can help to update your practice and ensure it remains evidence-based. Apply this article to your practice. Reflect on and write a short account of: • How this article might improve your practice when preparing and administering an IV infusion. • How you could use this information to educate nursing students or your colleagues on the appropriate methods for preparing and administering an IV infusion.

The Description and Analysis of the Complete Genome of Dermacoccus barathri FBCC-B549 Strain

Dermacoccus barathri is the first reported pathogen within the Dermacoccus genus to cause a catheter-related bloodstream infection, which occurred in 2015. In this study, the complete genome assembly of Dermacoccus barathri was constructed, and the complete genome of Dermacoccus barathri FBCC-B549 consists of a single chromosome (3,137,745 bp) without plasmids. The constructed genome of D. barathri was compared with those of two closely related species within the Dermacoccus genus. D. barathri exhibited a pattern similar to Dermacoccus abyssi in terms of gene clusters and synteny analysis. Contrary to previous studies, biosynthetic gene cluster (BGC) analysis for predicting secondary metabolites revealed the presence of the LAP biosynthesis pathway in the complete genome of D. barathri, predicting the potential synthesis of the secondary metabolite plantazolicin. Furthermore, an analysis to investigate the potential pathogenicity of D. barathri did not reveal any antibiotic resistance genes; however, nine virulence factors were identified in the Virulence Factor Database (VFDB). According to these matching results in the VFDB, despite identifying a few factors involved in biofilm formation, further research is required to determine the actual impact of D. barathri on pathogenicity. The complete genome of D. barathri is expected to serve as a valuable resource for future studies on D. barathri, which currently lack sufficient genomic sequence information.

Enhanced Antibacterial Properties of Titanium Surfaces through Diversified Ion Plating with Silver Atom Deposition

In this study, we investigate the antibacterial effect of silver atoms implanted into a thin surface layer of titanium at low energies using an alternative ion plating technology called Diversified Ion Plating. Silver atoms were incorporated into titanium samples using reactive low-voltage ion plating at 2 keV and 4 keV. Surface modifications and morphology were evaluated using wettability, profilometry measurements, and energy-dispersive spectroscopy. For a precise determination of the quantity and depth of implanted silver atoms on titanium surfaces, a combination of experimental techniques such as Rutherford Backscattering Spectrometry along with Monte Carlo simulations were utilized. To assess the antibacterial effects of the silver atoms incorporated into pure titanium surfaces, bacterial suspension immersion tests were performed with a standard strain of Staphylococcus aureus (ATCC 12600). The outcomes indicate that titanium surfaces implanted with silver atoms were more effective in inhibiting the growth of Staphylococcus aureus than pure titanium surfaces. Better results were found when the deposition was performed at 4 keV, indicating that a deeper implantation of silver, spanning a few nanometers, can result in a longer and more effective release of silver atoms. These findings suggest the potential for the development of new, cost-effective biomaterials, paving the way for improved implant materials in various health-related applications.

Fever and infections in surgical intensive care: an American Association for the Surgery of Trauma Critical Care Committee clinical consensus document

The evaluation and workup of fever and the use of antibiotics to treat infections is part of daily practice in the surgical intensive care unit (ICU). Fever can be infectious or non-infectious; it is important to distinguish between the two entities wherever possible. The evidence is growing for shortening the duration of antibiotic treatment of common infections. The purpose of this clinical consensus document, created by the American Association for the Surgery of Trauma Critical Care Committee, is to synthesize the available evidence, and to provide practical recommendations. We discuss the evaluation of fever, the indications to obtain cultures including urine, blood, and respiratory specimens for diagnosis of infections, the use of procalcitonin, and the decision to initiate empiric antibiotics. We then describe the treatment of common infections, specifically ventilator-associated pneumonia, catheter-associated urinary infection, catheter-related bloodstream infection, bacteremia, surgical site infection, intra-abdominal infection, ventriculitis, and necrotizing soft tissue infection.

Nosocomial outbreak caused by disinfectant-resistant Serratia marcescens in an adult intensive care unit, Hungary, February to March 2022

In 2022, an outbreak with severe bloodstream infections caused by Serratia marcescens occurred in an adult intensive care unit (ICU) in Hungary. Eight cases, five of whom died, were detected. Initial control measures could not stop the outbreak. We conducted a matched case-control study. In univariable analysis, the cases were more likely to be located around one sink in the ICU and had more medical procedures and medications than the controls, however, the multivariable analysis was not conclusive. Isolates from blood cultures of the cases and the ICU environment were closely related by whole genome sequencing and resistant or tolerant against the quaternary ammonium compound surface disinfectant used in the ICU. Thus, S. marcescens was able to survive in the environment despite regular cleaning and disinfection. The hospital replaced the disinfectant with another one, tightened the cleaning protocol and strengthened hand hygiene compliance among the healthcare workers. Together, these control measures have proved effective to prevent new cases. Our results highlight the importance of multidisciplinary outbreak investigations, including environmental sampling, molecular typing and testing for disinfectant resistance.

Is Camphor the Future in Supporting Therapy for Skin Infections?

The aim of this review is to present the potential application of camphor-a bicyclic monoterpene ketone-in the prevention of skin infections. Skin diseases represent a heterogeneous group of disorders characterized by prolonged symptoms that significantly diminish the quality of life. They affect the dermis, the epidermis, and even subcutaneous tissue. They very often have a bacterial or fungal background. Therapy for dermatological skin disorders is difficult and long-term. Therefore, it is important to find a compound, preferably of natural origin, that (i) prevents the initiation of this infection and (ii) supports the skin's repair process. Based on its documented anti-inflammatory, antibacterial, antifungal, anti-acne, anesthetic, strengthening, and warming properties, camphor can be used as a preventative measure in dermatological infectious diseases and as a component in medical and cosmetic products. This work discusses the structure and physicochemical properties of camphor, its occurrence, and methods of obtaining it from natural sources as well as through chemical synthesis. The use of camphor in industrial preparations is also presented. Additionally, after a detailed review of the literature, the metabolism of camphor, its interactions with other medicinal substances, and its antimicrobial properties against bacteria and fungi involved in skin diseases are discussed with regard to their resistance.

Medical Device-Associated Biofilm Infections and Multidrug-Resistant Pathogens

Medical devices such as venous catheters (VCs) and urinary catheters (UCs) are widely used in the hospital setting. However, the implantation of these devices is often accompanied by complications. About 60 to 70% of nosocomial infections (NIs) are linked to biofilms. The main complication is the ability of microorganisms to adhere to surfaces and form biofilms which protect them and help them to persist in the host. Indeed, by crossing the skin barrier, the insertion of VC inevitably allows skin flora or accidental environmental contaminants to access the underlying tissues and cause fatal complications like bloodstream infections (BSIs). In fact, 80,000 central venous catheters-BSIs (CVC-BSIs)-mainly occur in intensive care units (ICUs) with a death rate of 12 to 25%. Similarly, catheter-associated urinary tract infections (CA-UTIs) are the most commonlyhospital-acquired infections (HAIs) worldwide.These infections represent up to 40% of NIs.In this review, we present a summary of biofilm formation steps. We provide an overview of two main and important infections in clinical settings linked to medical devices, namely the catheter-asociated bloodstream infections (CA-BSIs) and catheter-associated urinary tract infections (CA-UTIs), and highlight also the most multidrug resistant bacteria implicated in these infections. Furthermore, we draw attention toseveral useful prevention strategies, and advanced antimicrobial and antifouling approaches developed to reduce bacterial colonization on catheter surfaces and the incidence of the catheter-related infections.

A Review of Recent Advancements in Sensor-Integrated Medical Tools

A medical tool is a general instrument intended for use in the prevention, diagnosis, and treatment of diseases in humans or other animals. Nowadays, sensors are widely employed in medical tools to analyze or quantify disease-related parameters for the diagnosis and monitoring of patients' diseases. Recent explosive advancements in sensor technologies have extended the integration and application of sensors in medical tools by providing more versatile in vivo sensing capabilities. These unique sensing capabilities, especially for medical tools for surgery or medical treatment, are getting more attention owing to the rapid growth of minimally invasive surgery. In this review, recent advancements in sensor-integrated medical tools are presented, and their necessity, use, and examples are comprehensively introduced. Specifically, medical tools often utilized for medical surgery or treatment, for example, medical needles, catheters, robotic surgery, sutures, endoscopes, and tubes, are covered, and in-depth discussions about the working mechanism used for each sensor-integrated medical tool are provided.

In vitro assessment of isopropanol leakage from antiseptic barrier caps into commonly used needleless connectors

BACKGROUND

Needleless connectors (NCs) can be disinfected using antiseptic barrier caps (ABCs) to reduce the risk of catheter-related bloodstream infections. However, recent evidence suggests that isopropanol can leak from the ABC into the NC, posing concern about their safe use. We sought to determine in vitro which ABC and NC parameters influence the leakage of isopropanol through the infusion circuit.

METHODS

We assessed 13 NCs and 4 ABCs available in the European market. In vitro circuits consisting of an isopropanol cap, a NC, and an 11-cm catheter line were created. The circuits were left in place for 1 to 7 days at room temperature to assess the kinetics of isopropanol leakage. Isopropanol content in ABC and in circuit flushing solutions (5 mL NaCl 0.9%) after exposure to the cap were measured using gas chromatography with a flame ionization detector.

RESULTS

The leakage of isopropanol from the cap to the NC was dependent on the NC, but not the cap. The NC mechanism did not predict the leakage of isopropanol. The Q-Syte NC exhibited the most isopropanol leakage (7.01±1.03 mg and 28.32±2.62 mg at 24 hours and 7 days, respectively), whereas the Caresite NC had the lowest isopropanol leakage at 7 days (1.69±0.01 mg).

CONCLUSION

The use of isopropanol ABCs can cause isopropanol leakage into the catheter circuit according to NC parameters. Caution should be exercised when using these devices, especially in the pediatric and neonatal population.

Risk factors of central catheter bloodstream infections in intensive care units: A systematic review and meta-analysis

BACKGROUND

Central catheter bloodstream infections (CRBSI) is a major cause of healthcare-associated infections. However, few factors are generally accepted and some studies have conflicting finding about some factors, possibly caused by limitation associated with an individual study. This study was to identify risk factors for CRBSI in intensive care units.

METHODS

We searched the PubMed, Cochrane Library, Web of science and EMBASE databases and the 4 top Chinese-language databases, including WanFang data, China National Knowledge Infrastructure (CNKI), and Chinese Science and Technology Journal Database (VIP), China Biology Medicine disc (CBM) as of July 2023. Case control and cohort studies were included. Two authors independently screened the literature and evaluated the quality of the studies using the Newcastle-Ottawa scale (NOS). The pooled effect size was estimated using the odds ratio (OR), and the corresponding 95% confidence interval (CI) was calculated. The Cochrane Q (χ2) and I2 tests were used to assess heterogeneity among studies, and each risk factor was tested for its robustness using fixed- or random-effects models.

FINDINGS

A total of 32 studies enrolled, among which eleven factors were identified, they were divided into two categories: modifiable and unmodifiable factors. Modifiable factors: duration of catheterization (≥ 5d) (OR: 2.07, 95%CI: 1.41-3.03), duration of catheterization (≥ 7d) (OR: 3.62, 95%CI: 2.65-4.97), duration of catheterization (≥ 14d)(OR: 4.85, 95%CI: 3.35-7.01), total parenteral nutrition (OR: 2.27,95%CI: 1.56-3.29), use of multiple-lumen catheters(OR: 3.41, 95%CI: 2.27-5.11), times of tube indwelling (OR: 3.50, 95%CI: 2.93-4.17), length of ICU stay (OR: 4.05, 95%CI: 2.41-6.80), the position of indwelling(OR: 2.41, 95%CI: 2.03-2.85); Unmodifiable factors: APACHEII scores (OR: 1.84, 95%CI: 1.54-2.20), Age≥ 60 years old (OR: 2.19, 95%CI: 1.76-2.73), the extensive use of antibiotic (OR: 3.54, 95%CI: 1.65-7.61), Diabetes mellitus (OR: 3.06, 95%CI: 2.56-3.66), Immunosuppression (OR: 2.87, 95%CI: 2.08-3.95).

CONCLUSIONS

Effective interventions targeting the above modifiable factors may reduce the risk of developing CRBSI in ICU and improve the clinical outcome of patients. Further prospective studies are needed to confirm these findings.

Disinfection of needleless connectors for catheters in one second using a hand-held UV device

BACKGROUND

The standard of care for disinfecting needleless connectors (NCs) of central venous catheters includes alcohol-containing caps or up to a 15-second scrub with alcohol or chlorhexidine. Due to the clinical impact and high cost of treating Central line-associated bloodstream infections (CLABSI), reducing the incidence of CLABSI is a priority for public health and of the Centers for Disease Control. Alcohol-containing caps have been demonstrated to disinfect external NC surfaces, but not the internal surface. Ultraviolet light (UV-C) is a strategy for disinfection of NC internal and external surfaces.

METHODS

Four clinically relevant bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa) and Candida albicans were inoculated on NCs. Disinfection efficacy was measured after exposure to one second of 285 nm UV-C light at 48 mW/cm2 in a proprietary handheld device and UV-C transparent NC or standard of care. Disinfection of internal and external surfaces of NC inoculated with S aureus using alcohol caps, and UV-C was also compared.

RESULTS

A 4-log reduction in colony forming units (CFUs) on the interior and exterior surfaces of the UV-transparent NC of clinically relevant pathogens was observed with UV-C light at this power for 1 second.

DISCUSSION

We demonstrated the efficacy of UV-C for the disinfection of NCs in one second using the UV-C device in benchtop studies.

CONCLUSIONS

This device holds promise for reducing CLABSI, and clinical studies are planned.

Sodium bicarbonate is a potential alternative to classic heparin as a lock solution for non-tunneled dialysis catheters: a result from the prospective randomized BicarbLock trial

OBJECTIVE

Temporary vascular access is mandatory for acute hemodialysis. Heparin lock solution is the standard of care worldwide. Many lock solutions were studied in terms of thrombosis and catheter-related infection prevention, but none replaced heparin as a standard measure. Our main aim is to investigate the effectiveness of sodium bicarbonate (NaHCO3), a ubiquitous and cheap option as a catheter lock solution, in comparison with traditionally used heparin in non-tunneled hemodialysis catheters.

METHODS

We conducted our prospective study between March 2021 and March 2022. Our study included 441 patients > 18 years old who needed either femoral or jugular non-tunneled dialysis catheters. Patients were assigned to either heparin (5000 IU/ml) or 8.4% sodium bicarbonate on a consecutive basis. Basic characteristics and information regarding catheters, dialysis sessions, and complications were recorded. We divided patients according to the catheter insertion site as well as the lock solution.

RESULTS

We analyzed 426 patients divided into four groups: jugular heparin (n = 113), jugular bicarbonate (n = 113), femoral heparin (n = 113), and femoral bicarbonate (n = 100). Basal characteristics were similar for all groups. The mean time to last effective dialysis in our institution was 10.7 ± 12.1 days for heparin vs 11.5 ± 10.8 days for the bicarbonate group. 25 (5.9%) patients had some kind of blood flow problems (13 in the heparin and 12 in the bicarbonate group). There was no significant difference in terms of catheter malfunction among groups (p = 0.50). Out of these 25 cases, only 12 (7 in heparin and 5 in the bicarbonate arm) had catheter dysfunction (p = 0.386). Sixty-four patients (28%) with jugular catheters were discharged with patent catheters and continued their dialysis in other facilities.

CONCLUSION

Sodium bicarbonate is as effective as classic unfractionated heparin in preventing catheter lumen thrombosis with a comparable incidence of catheter-related complications. Furthermore, it is a cost-effective option that can be used confidently, especially when heparin is contraindicated.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04772209 (26.02.2021).

Flexible and Biocompatible Antifouling Polyurethane Surfaces Incorporating Tethered Antimicrobial Peptides through Click Reactions

Efficient, simple antibacterial materials to combat implant-associated infections are much in demand. Herein, the development of polyurethanes, both cross-linked thermoset and flexible and versatile thermoplastic, suitable for "click on demand" attachment of antibacterial compounds enabled via incorporation of an alkyne-containing diol monomer in the polymer backbone, is described. By employing different polyolic polytetrahydrofurans, isocyanates, and chain extenders, a robust and flexible material comparable to commercial thermoplastic polyurethane is prepared. A series of short synthetic antimicrobial peptides are designed, synthesized, and covalently attached in a single coupling step to generate a homogenous coating. The lead material is shown to be biocompatible and does not display any toxicity against either mouse fibroblasts or reconstructed human epidermis according to ISO and OECD guidelines. The repelling performance of the peptide-coated materials is illustrated against colonization and biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis on coated plastic films and finally, on coated commercial central venous catheters employing LIVE/DEAD staining, confocal laser scanning microscopy, and bacterial counts. This study presents the successful development of a versatile and scalable polyurethane with the potential for use in the medical field to reduce the impact of bacterial biofilms.

Using the Traditional Ex Vivo Whole Blood Model to Discriminate Bacteria by Their Inducible Host Responses

Whole blood models are rapid and versatile for determining immune responses to inflammatory and infectious stimuli, but they have not been used for bacterial discrimination. Staphylococcus aureus, S. epidermidis and Escherichia coli are the most common causes of invasive disease, and rapid testing strategies utilising host responses remain elusive. Currently, immune responses can only discriminate between bacterial 'domains' (fungi, bacteria and viruses), and very few studies can use immune responses to discriminate bacteria at the species and strain level. Here, whole blood was used to investigate the relationship between host responses and bacterial strains. Results confirmed unique temporal profiles for the 10 parameters studied: IL-6, MIP-1α, MIP-3α, IL-10, resistin, phagocytosis, S100A8, S100A8/A9, C5a and TF3. Pairwise analysis confirmed that IL-6, resistin, phagocytosis, C5a and S100A8/A9 could be used in a discrimination scheme to identify to the strain level. Linear discriminant analysis (LDA) confirmed that (i) IL-6, MIP-3α and TF3 could predict genera with 95% accuracy; (ii) IL-6, phagocytosis, resistin and TF3 could predict species at 90% accuracy and (iii) phagocytosis, S100A8 and IL-10 predicted strain at 40% accuracy. These data are important because they confirm the proof of concept that host biomarker panels could be used to identify bacterial pathogens.

Knowledge, practice and associated factors towards intravenous cannula-related infection prevention among nurses working at Northwest Amhara Regional State Comprehensive Specialized Hospitals, Ethiopia

BACKGROUND

Intravenous cannula-related infections are one of the leading causes of healthcare-associated infections. It leads to morbidity and mortality in hospitalized patients. Nurses play a significant role in the prevention of these infections. Whereas in Ethiopia, there is limited information and published studies done on nurses' knowledge, practice, and associated factors and also most of other available studies done only the magnitude it lack associated factors. The purpose of this study was to assess nurses' knowledge, practice, and associated factors toward intravenous cannula-related infection prevention.

METHODS

An institution-based cross-sectional study was conducted at Northwest Amhara Regional State Comprehensive Specialized Hospitals on May 1-30/2022. By using single population proportion formula the sample size was determined; we used a 50% proportion value (0.05), and 95% Confidence Interval 5% margin of error. A simple random sampling method was used to select 423 nurses. The data were collected by using structured pretested self-administered questionnaires. Then coded, and enter into epi-data version 4.6 and exported into the statistical package for social science version 23 for cleaning and analyzing the data. Data were presented by texts, tables, and figures. A binary logistic regression model was used to assess the association between variables. Based on the adjusted odds ratio, variables having a p-value less than 0.05 with a 95% confidence interval were used to state associated with the outcome variables.

RESULTS

A total of 412 nurses participated in this study with 97.4% response rate. The participants had good knowledge and practice in proportions of (54. 9%) and (53. 4%) respectively. Being male, working wards/units, having training, and a higher educational level were factors that were significantly associated to having good knowledge. Working wards/units, having good knowledge, training, and access to guidelines were significantly associated with performing good practice.

CONCLUSION

The finding of this study revealed that nearly half of the nurses had poor knowledge and practice in intravenous cannula-related infection prevention. As a result, hospital administrators and other concerned stakeholders better to prepare and ensure that guidelines are available, provide training, and develop the educational levels of nurses.

Is central venous catheter in haemodialysis still the main factor of mortality after hospitalization?

BACKGROUND

Haemodialysis is the most frequently prescribed Renal Replacement Therapy modality worldwide. However, patients undergoing this therapy have an unpredictable evolution related to vascular access.

OBJECTIVE

To determine the factors associated with the mortality and hospitalization rate in haemodialysis patients at a third-level care Centre in the Dominican Republic.

METHODS

This was an observational and prospective study involving a cohort of 192 haemodialysis patients. The patient selection was non-probabilistic for convenience, and a direct source questionnaire was applied.

RESULTS

Of the 192 patients in the cohort, 103 (53.6%) were hospitalized and evaluated. The most frequent cause of hospitalization was catheter-related bloodstream infections (53.4%). Almost one-third (28.2%) of the hospitalized patients died, mostly due to infections (12.6%). Of those who died 29 patients (90%) had a Central venous catheter (CVC) with a non-tunnelled catheter (NTCVC) (65.5%); having an NTC CVC makes a patient 85.5 times more likely to be hospitalized than patients with arteriovenous fistulas.

CONCLUSION

Vascular access plays a predominant role in the hospitalization and mortality rates in haemodialysis. Patients with an arteriovenous fistula obtained significantly better outcomes than those with central venous catheters.

The accuracy of fully-automated algorithms for the surveillance of central venous catheter-related bloodstream infection in hospitalised patients

BACKGROUND

Continuous surveillance for healthcare-associated infections such as central venous catheter-related bloodstream infections (CVC-BSI) is crucial for prevention. However, traditional surveillance methods are resource-intensive and prone to bias. This study aimed to develop and validate fully-automated surveillance algorithms for CVC-BSI.

METHODS

Two algorithms were developed using electronic health record data from 1000 admissions with a positive blood culture (BCx) at Karolinska University Hospital from 2017: (1) Combining microbiological findings in BCx and CVC cultures with BSI symptoms; (2) Only using microbiological findings. These algorithms were validated in 5170 potential CVC-BSI-episodes from all admissions in 2018-2019, and results extrapolated to all potential CVC-BSI-episodes within this period (n = 181,354). The reference standard was manual record review according to ECDC's definition of microbiologically confirmed CVC-BSI (CRI3-CVC).

RESULTS

In the potential CVC-BSI-episodes, 51 fulfilled ECDC's definition and the algorithms identified 47 and 49 episodes as CVC-BSI, respectively. Both algorithms performed well in assessing CVC-BSI. Overall, algorithm 2 performed slightly better with in the total period a sensitivity of 0.880 (95%-CI 0.783-0.959), specificity of 1.000 (95%-CI 0.999-1.000), PPV of 0.918 (95%-CI 0.833-0.981) and NPV of 1.000 (95%-CI 0.999-1.000). Incidence according to the reference and algorithm 2 was 0.33 and 0.31 per 1000 in-patient hospital-days, respectively.

CONCLUSIONS

Both fully-automated surveillance algorithms for CVC-BSI performed well and could effectively replace manual surveillance. The simpler algorithm, using only microbiology data, is suitable when BCx testing adheres to recommendations, otherwise the algorithm using symptom data might be required. Further validation in other settings is necessary to assess the algorithms' generalisability.

Toolbox of Characterized Genetic Parts for Staphylococcus aureus

Staphylococcus aureus is an important clinical bacterium prevalent in human-associated microbiomes and the cause of many diseases. However, S. aureus has been intractable to synthetic biology approaches due to limited characterized genetic parts for this nonmodel Gram-positive bacterium. Moreover, genetic manipulation of S. aureus has relied on cumbersome and inefficient cloning strategies. Here, we report the first standardized genetic parts toolbox for S. aureus, which includes characterized promoters, ribosome binding sites, terminators, and plasmid replicons from a variety of bacteria for precise control of gene expression. We established a standard relative expression unit (REU) for S. aureus using a plasmid reference and characterized genetic parts in standardized REUs using S. aureus ATCC 12600. We constructed promoter and terminator part plasmids that are compatible with an efficient Type IIS DNA assembly strategy to effectively build multipart DNA constructs. A library of 24 constitutive promoters was built and characterized in S. aureus, which showed a 380-fold activity range. This promoter library was also assayed in Bacillus subtilis (122-fold activity range) to demonstrate the transferability of the constitutive promoters between these Gram-positive bacteria. By applying an iterative design-build-test-learn cycle, we demonstrated the use of our toolbox for the rational design and engineering of a tetracycline sensor in S. aureus using the PXyl-TetO aTc-inducible promoter that achieved 25.8-fold induction. This toolbox greatly expands the growing number of genetic parts for Gram-positive bacteria and will allow researchers to leverage synthetic biology approaches to study and engineer cellular processes in S. aureus.

Antibody-Mediated Serum Resistance Protects Pseudomonas aeruginosa During Bloodstream Infections

BACKGROUND

Pseudomonas aeruginosa is a frequent pathogen isolated from bacterial bloodstream infection (BSI) and is associated with high mortality. To survive in the blood, P aeruginosa must resist the bactericidal action of complement (ie, serum killing). Antibodies usually promote serum killing through the classical complement pathway; however, "cloaking antibodies" (cAbs) have been described, which paradoxically protect bacteria from serum killing. The relevance of cAbs in P aeruginosa BSI is unknown.

METHODS

Serum and P aeruginosa were collected from a cohort of 100 patients with BSI. Isolates were tested for sensitivity to healthy control serum (HCS). cAb prevalence was determined in sera. Patient sera were mixed with HCS to determine if killing of the matched isolate was inhibited.

RESULTS

Overall, 36 patients had elevated titers of cAbs, and 34 isolates were sensitive to HCS killing. Fifteen patients had cAbs and HCS-sensitive isolates; of these patients, 14 had serum that protected their matched bacteria from HCS killing. Patients with cAbs were less likely to be neutropenic or have comorbidities.

CONCLUSIONS

cAbs are prevalent in patients with P aeruginosa BSI and allow survival of otherwise serum-sensitive bacteria in the bloodstream. Generation of cAbs may be a risk factor for the development of BSI.

Heparin-network-mediated long-lasting coatings on intravascular catheters for adaptive antithrombosis and antibacterial infection

Bacteria-associated infections and thrombosis, particularly catheter-related bloodstream infections and catheter-related thrombosis, are life-threatening complications. Herein, we utilize a concise assembly of heparin sodium with organosilicon quaternary ammonium surfactant to fabricate a multifunctional coating complex. In contrast to conventional one-time coatings, the complex attaches to medical devices with arbitrary shapes and compositions through a facile dipping process and further forms robust coatings to treat catheter-related bloodstream infections and thrombosis simultaneously. Through their robustness and adaptively dissociation, coatings not only exhibit good stability under extreme conditions but also significantly reduce thrombus adhesion by 60%, and shows broad-spectrum antibacterial activity ( > 97%) in vitro and in vivo. Furthermore, an ex vivo rabbit model verifies that the coated catheter has the potential to prevent catheter-related bacteremia during implantation. This substrate-independent and portable long-lasting multifunctional coating can be employed to meet the increasing clinical demands for combating catheter-related bloodstream infections and thrombosis.

Metastatic spondylodiscitis in central venous catheter related bloodstream infections in hemodialysis patients: Risk factors and prognosis

BACKGROUND

Infection is one of the most common causes of death in hemodialysis patients. Catheter infections are among the most common infections in this patient group. Spondylodiscitis which has a high incidence in ESRD is more commonly encountered in patients with CVCs compared to AVF. In this study, we aimed to evaluate the frequency and risk factors of spondylodiscitis in catheter-related bloodstream infections in hemodialysis patients.

METHODS

In total, 1620 patients were screened and 42 male and 35 female patients with central catheter infection with a mean age of 65.8 ± 14.9 years were included in this study. Patients with metastatic infections secondary to CVC related bloodstream infections were determined. The diagnosis of spondylodiscitis was based on clinical information, computed tomography (CT) and magnetic resonance imaging (MRI), and vertebral cultures.

RESULTS

Metastatic infection due to catheter infection was observed in 15 patients (19.5%). In the regression analysis, CRP level and RRT time were found to be significantly correlated with the development of metastatic infection. Spondylodiscitis was the most common subtype of metastatic infections (8/15). The presence of lumbar hernia was associated with increased risk of metastatic spondylodiscitis in case of catheter infection in hemodialysis patients. The only factor associated with resistance to medical treatment was the time from admission to diagnosis.

CONCLUSION

Patients with long RRT time and high blood CRP levels on admission should be closely monitored for metastatic infection in patients with CVC related bloodstream infections. Screening for spondylodiscitis with CT or MRI should be performed in patients with symptoms, since early diagnosis may prevent the development of possible neurological deficits and treatment resistance.

Integration of Riboflavin-Modified Carbon Fiber Mesh Electrode Systems in a 3D-Printed Catheter Hub

BACKGROUND

Catheter line infection is a common complication within clinical environments, and there is a pressing need for technological options to aid in reducing the possibility of sepsis. The early identification of contamination could be pivotal in reducing cases and improving outcomes.

METHOD

A sensing rationale based on a riboflavin-modified electrode system integrated within a modified 3D-printed catheter needle-free connector is proposed, which can monitor changes in pH brought about by bacterial contamination.

RESULTS

Riboflavin, vitamin B2, is a biocompatible chemical that possesses a redox-active flavin core that is pH dependent. The oxidation peak potential of the adsorbed riboflavin responds linearly to changes in pH with a near-Nernstian behavior of 63 mV/pH unit and is capable of accurately monitoring the pH of an authentic IV infusate.

CONCLUSIONS

The proof of principle is demonstrated with an electrode-printed hub design offering a valuable foundation from which to explore bacterial interactions within the catheter lumen with the potential of providing an early warning of contamination.

Novel Antibacterial Agents SAAP-148 and Halicin Combat Gram-Negative Bacteria Colonizing Catheters

The antibiotic management of catheter-related infections (CRIs) often fails owing to the emergence of antimicrobial-resistant strains and/or biofilm/persister apparitions. Thus, we investigated the efficacy of two novel antimicrobial agents, i.e., the synthetic peptide SAAP-148 and the novel antibiotic halicin, against Gram-negative bacteria (GNB) colonizing catheters. The antibacterial, anti-biofilm, and anti-persister activities of both agents were evaluated against Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae strains. The enrolled strains were isolated from catheters and selected based on their resistance to at least three antibiotic classes and biofilm formation potential. Furthermore, the hemolysis and endotoxin neutralization abilities of these agents were explored. The bactericidal activity of both agents was reduced in urine and plasma as compared to buffered saline. In a dose-dependent manner, SAAP-148 and halicin reduced bacterial counts in 24 h preformed biofilms on silicone elastomer discs and eliminated persisters originating from antibiotic-exposed mature 7-day biofilms, with halicin being less effective than SAAP-148. Importantly, SAAP-148 and halicin acted synergistically on E. coli and K. pneumoniae biofilms but not on A. baumannii biofilms. The peptide, but not halicin, decreased the production of IL-12p40 upon exposure to UV-killed bacteria. This preliminary study showed that SAAP-148 and halicin alone/in combination are promising candidates to fight GNB colonizing catheters.

Amiodarone-induced phlebitis: incidence and adherence to a clinical practice guideline

AIMS

Intravenous amiodarone is an irritant of peripheral blood vessels with phlebitis as an adverse effect. The aims were to determine the incidence of intravenous amiodarone-induced phlebitis, to describe adherence to a clinical practice guideline, and to determine how characteristics were distributed between those with and without phlebitis.

METHODS AND RESULTS

A prospective observational study was conducted. Adult patients treated with amiodarone through a peripheral intravenous catheter (PIVC) or a central venous catheter were included. PIVC characteristics were measured using the PIVC mini questionnaire. Patients with ≥two signs of phlebitis were categorized as having phlebitis. Adherence to the clinical practice guideline was registered on a standard abstract sheet. Data were collected from the amiodarone start-up to 2 days after the amiodarone was discontinued. In total, 124 patients with amiodarone infusions were observed, of which 69% were administered via a PIVC. The phlebitis rate was 44%. Fifty-three per cent developed amiodarone-induced phlebitis during the infusion phase, while 47% presented phlebitis during the post-infusion phase. The three most observed signs or symptoms of phlebitis were redness (87%), pain (81%), and swelling (71%). The most commonly used PIVC site was the elbow, and 35% of the PIVCs were large (18 gauge), which was the last preferred site and size according to the clinical practice guideline.

CONCLUSION

A large proportion of the patients developed amiodarone-induced phlebitis. The adherence to the clinical practice guideline was not optimal according to the PIVC recommendations. Prevention of amiodarone-induced phlebitis should have high priority to reduce patient harm.

The bactericidal and antibiofilm effects of a lysine-substituted hybrid peptide, CM-10K14K, on biofilm-forming Staphylococcus epidermidis

Staphylococci, notably biofilm-forming Staphylococcus epidermidis, have been recognized as global nosocomial pathogens in medical device-related infections. Their potential to attach to and form biofilm on indwelling catheters are significant factors impeding conventional treatment. Due to their extensive antimicrobial and antibiofilm actions, antimicrobial peptides (AMPs) have attracted interest as promising alternative compounds for curing difficult-to-treat, biofilm-forming bacterial infections. Cecropin A-melittin or CM, a well-known hybrid peptide, exhibits broad-spectrum antimicrobial activity, however it also possesses high toxicity. In the current study, a series of hybrid CM derivatives was designed using an amino acid substitution strategy to explore potential antibacterial and antibiofilm peptides with low toxicity. Among the derivatives, CM-10K14K showed the least hemolysis along with potent antibacterial activity against biofilm-forming S. epidermidis (MICs = 3.91 μg/mL) and rapid killing after 15 min exposure (MBCs = 7.81 μg/mL). It can prevent the formation of S. epidermidis biofilm and also exhibited a dose-dependent eradication activity on mature or established S. epidermidis biofilm. In addition, it decreased the development of biofilm by surviving bacteria, and formation of biofilm on the surface of CM-10K14K-impregnated catheters. Released CM-10K14K decreased planktonic bacterial growth and inhibited biofilm formation by S. epidermidis in a dose-dependent manner for 6 and 24 h post-exposure. Impregnation of CM-10K14K prevented bacterial attachment on catheters and thus decreased formation of extensive biofilms. SEM images supported the antibiofilm activity of CM-10K14K. Flow cytometry analysis and TEM images demonstrated a membrane-active mechanism of CM-10K14K, inducing depolarization and permeabilization, and subsequent membrane rupture leading to cell death. The presence of an interaction with bacterial DNA was verified by gel retardation assay. These antibacterial and antibiofilm activities of CM-10K14K suggest its potential application to urinary catheters for prevention of biofilm-forming colonization or for treatment of medical devices infected with S. epidermidis.

Understanding the diagnosis of catheter-related bloodstream infection: real-time monitoring of biofilm growth dynamics using time-lapse optical microscopy

Background

The differential time to positivity (DTTP) technique is recommended for the conservative diagnosis of catheter-related bloodstream infection (C-RBSI). The technique is based on a 120-minute difference between microbial growth in blood drawn through the catheter and blood drawn through a peripheral vein. However, this cut-off has failed to confirm C-RBSI caused by Candida spp. and Staphylococcus aureus.

Objective

We hypothesized that the biofilm of both microorganisms disperses faster than that of other microorganisms and that microbial load is rapidly equalized between catheter and peripheral blood. Therefore, our aim was to compare the biofilm dynamics of various microorganisms.

Methods

Biofilm of ATCC strains of methicillin-resistant Staphylococcus epidermidis, methicillin-susceptible S. aureus, Enterococcus faecalis, Escherichia coli and Candida albicans was grown on silicon disks and analyzed using time-lapse optical microscopy. The time-lapse images of biofilms were processed using ImageJ2 software. Cell dispersal time and biofilm thickness were calculated.

Results

The mean (standard deviation) dispersal time in C. albicans and S. aureus biofilms was at least nearly 3 hours lower than in biofilm of S. epidermidis, and at least 15 minutes than in E. faecalis and E. coli biofilms.

Conclusion

Our findings could explain why early dissemination of cells in C. albicans and S. aureus prevents us from confirming or ruling out the catheter as the source of the bloodstream infection using the cut-off of 120 minutes in the DTTP technique. In addition, DTTP may not be sufficiently reliable for E. coli since their dispersion time is less than the cut-off of 120 minutes.

Venous Access: National Guideline and Registry Development (VANGUARD): Advancing Patient-Centered Venous Access Care Through the Development of a National Coordinated Registry Network

There are over 8 million central venous access devices inserted each year, many in patients with chronic conditions who rely on central access for life-preserving therapies. Central venous access device-related complications can be life-threatening and add tens of billions of dollars to health care costs, while their incidence is most likely grossly mis- or underreported by medical institutions. In this communication, we review the challenges that impair retention, exchange, and analysis of data necessary for a meaningful understanding of critical events and outcomes in this clinical domain. The difficulty is not only with data extraction and harmonization from electronic health records, national surveillance systems, or other health information repositories where data might be stored. The problem is that reliable and appropriate data are not recorded, or falsely recorded, at least in part because policy, payment, penalties, proprietary concerns, and workflow burdens discourage completeness and accuracy. We provide a roadmap for the development of health care information systems and infrastructure that address these challenges, framed within the context of research studies that build a framework of standardized terminology, decision support, data capture, and information exchange necessary for the task. This roadmap is embedded in a broader Coordinated Registry Network Learning Community, and facilitated by the Medical Device Epidemiology Network, a Public-Private Partnership sponsored by the US Food and Drug Administration, with the scope of advancing methods, national and international infrastructure, and partnerships needed for the evaluation of medical devices throughout their total life cycle.

Selenium nanoparticles: Enhanced nutrition and beyond

Selenium is a trace nutrient that has both nutritional and nutraceutical functions, whereas narrow nutritional range of selenium intake limits its use. Selenium nanoparticles (SeNPs) are less toxic and more bioavailable than traditional forms of selenium, suggesting that SeNPs have the potential to replace traditional selenium in food industries and/or biomedical fields. From the perspective of how SeNPs can be applied in health area, this review comprehensively discusses SeNPs in terms of its preparation, nutritional aspect, detoxification effect of heavy metals, nutraceutical functions and anti-pathogenic microorganism effects. By physical, chemical, or biological methods, inorganic selenium can be transformed into SeNPs which have increased stability and bioavailability as well as low toxicity. SeNPs are more effective than traditional selenium form in synthesizing selenoproteins like glutathione peroxidases. SeNPs can reshape the digestive system to facilitate digestion and absorption of nutrients. SeNPs have shown excellent potential to adjunctively treat cancer patients, enhance immune system, control diabetes, and prevent rheumatoid arthritis. Additionally, SeNPs have good microbial anti-pathogenic effects and can be used with other antimicrobial agents to fight against pathogenic bacteria, fungi, or viruses. Development of novel SeNPs with enhanced functions can greatly benefit the food-, nutraceutical-, and biomedical industries.

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.

Foundation for implementing a comprehensive vascular access excellence initiative organization-wide to improve vascular access device insertion and standardize care: best practice for an acute care hospital

INTRODUCTION

In 2016, a 263-bed public district hospital in California trialed a peripheral intravenous catheter (PIVC) inserted using ultrasound, with the potential to increase first attempt success in difficult intravenous access (DIVA) patients. This led to the implementation of a hospital-wide initiative to improve nursing vascular access skills and expedite vascular access device (VAD) placement.

METHODS

To trial a PIVC and ultrasound-guided (USG) insertion, a training program was developed and led to a doctoral Capstone project piloting an evidence-based nurse-driven protocol for the identification of DIVA patients. A Vascular Access Committee was established to achieve vascular access excellence throughout the hospital by increasing the number of nurses with advanced skills in VAD placement and by developing a central venous access device (CVAD) insertion and maintenance bundle to decrease the incidence of central line-associated bloodstream infections (CLABSI). With ongoing support of nursing leadership and achievement of ANCC Magnet Recognition® in 2021, the hospital developed a comprehensive initiative to provide patients with a consistent level of nursing expertise for VAD placement across all shifts.

RESULTS

Requests for USGPIVCs increased throughout the hospital, DIVA patients themselves requested ultrasound guidance be used for PIVC insertions, and there were fewer requests for Emergency Department (ED) physicians to insert CVADs. From the related Doctor of Nursing Practice (DNP) Capstone project, there were higher first-attempt cannulation successes, longer PIVC dwell times, and a reduction in devices and supplies utilized. The CVAD bundles resulted in the number of central line-associated bloodstream infections decreasing from four in 2019 to one in 2020. Since the initiative's inception, a total of 92 nurses completed the USGPIVC insertion training, and patient access to advanced-skilled clinicians is now available around the clock.

DISCUSSION

This manuscript discusses the initiative implemented to standardize patient care through a collaborative multidisciplinary approach and has potential generalizability to other acute care hospitals to reduce associated healthcare costs and to prevent poor patient outcomes by expediting the arrival of a vascular access nurse for DIVA patients.

CONCLUSION

The vascular access excellence initiative implemented provided an effective strategy to enhance the skills and confidence of nurses in VAD placement and improved efficiency in processes to expedite the arrival of an advanced skilled nurse to place VADs on DIVA. Targeted educational initiatives improved patient outcomes by reducing catheter-related bloodstream infections.

Catheter-Related Bloodstream Infections among patients on maintenance haemodialysis: a cross-sectional study at a tertiary hospital in Ghana

BACKGROUND

Catheter-Related Bloodstream Infections (CRBSIs) are notable complications among patients receiving maintenance haemodialysis. However, data on the prevalence of CRBSIs is lacking. This study was conducted to determine the prevalence and factors associated with CRBSIs among patients receiving haemodialysis in the renal unit of the largest tertiary hospital in Ghana.

METHODS

A hospital-based cross-sectional study was conducted on patients receiving maintenance haemodialysis via central venous catheters (CVC) between September 2021 and April 2022. Multivariate analysis using logistic regression was used to determine the risk factors that were predictive of CRBSI. Analysis was performed using SPSS version 23 and a p-value<0.05 was statistically significant.

RESULTS

The prevalence of CRBSI was 34.2% (52/152). Of these, more than half of them (53.9%(28/52)) had Possible CRBSI while 11.5% (6/52) had Definite CRBSI. Among the positive cultures, 62% (21/34) were from catheter sites whilst the rest were from peripheral blood. Gram-negative cultures made up 53% (18/34) of positive cultures with the rest being Gram positive cultures. Acinetobacter baumannii (33.3% (6/18)) was the commonest organism isolated among Gram-negative cultures whilst Coagulase negative Staphylococci (43.7% (7/16)) was the commonest organism isolated among Gram-positve cultures. Gram-negative bacilli were more predominant in this study making up 52.9% of the total bacteria cultured. Sex, duration of maintenance dialysis, underlying cause of End-stage kidney disease, mean corpuscular haemoglobin (MCH), neutrophil count and lymphocyte count were significantly predictive of CRBSI status (p<0.05).

CONCLUSION

There was a high prevalence of CRBSI among patients undergoing haemodialysis. The commonest causative agent was Coagulase negative Staphylococci, however there was a predominance of Gram-negative bacilli as compared to Gram positive cocci. There is a need to set up infection surveillance unit in the renal unit to track CRBSI and put in place measures to reduce these CRBSI.

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.

Surface grafting of polymeric catheters and stents to prevent biofilm formation of pathogenic bacteria

BACKGROUND

Tecothane (medical grade of polyurethane) is strongly involved in the fabrication of metallic and polymeric-based medical devices (e.g., catheters and stents) as they can withstand cardiac cycle-related forces without deforming or failing, and they can mimic tissue behavior. The main problem is microbial contamination and formation of pathogenic biofilms on such solid surfaces within the human body. Accordingly, our hypothesis is the coating of tecothane outer surfaces with antibacterial agents through the electro-deposition or chemical grafting of anti-biofilm agents onto the stent and catheter surfaces.

RESULTS

Tecothane is grafted with itaconic acid for cross-linking the polyethyleneimine (PEI) as the protective-active layer. Accordingly, the grafting of poly-itaconic acid onto the Tecothane was achieved by three different methods: wet-chemical approach, electro-polymerization, or by using plasma treatment. The successful modifications were verified using Fourier Transform Infrared (FTIR) spectroscopy, grafting percentage calculations, electrochemical, and microscopic monitoring of biofilm formation. The grafting efficiency of itaconic acid was over 3.2% (w/w) at 60 ℃ after 6 h of the catheter chemical modification. Bio-electrochemical signals of biofilms have been seriously reduced after chemical modification because of the inhibition of biofilm formation (for both Pseudomonas aeruginosa and Staphylococcus aureus) over a period of 9 days.

CONCLUSION

Chemical functionalization of the polyurethane materials with the antimicrobial and anti-biofilm agents led to a significant decrease in the formation of pathogenic biofilms. This promising proof-concept will open the door to explore further surface protection with potential anti-biofilm agents providing better and sustainable productions of stents and catheters biomaterials.

Antibiotics use patterns in end-of-life cancer patients and medical staff's perception of antimicrobial stewardship programs

BACKGROUND/AIMS

While most cancer patients with end-of-life (EOL) care receive antibiotic treatments, antibiotic use should be decided appropriately considering the benefits, side effects, resistance, and cost effects. Antimicrobial stewardship programs (ASP) are important for patients with EOL care, but there is limited study analyzing actual antibiotic use in EOL care and the perceptions of Korean medical staff.

METHODS

Electronic medical records of 149 deceased cancer patients hospitalized in the medical hospitalist units at Asan Medical Center in Seoul from May 2019 to September 2021 were reviewed. Basic information, antibiotic use, duration, and changes were investigated. We surveyed medical staff's perceptions of antibiotics in cancer patients with EOL.

RESULTS

Of the 149 cancer patients with EOL care, 146 (98.0%) agreed with physician orders for life-sustaining treatment (POLST). In total, 143 (95.9%) received antibiotics, 110 (76.9%) received combination antibiotic treatment, and 116 (81.1%) were given antibiotics until the day of death. In a survey of 60 medical staff, 42 (70.0%) did not know about ASP, and 24 (40.0%) thought ASP was important in EOL care. Nineteen doctors (31.7%) discussed the use or discontinuation of antibiotics with patients or caregivers when writing POLST, but only 8 patients (5.6%) stopped antibiotics after POLST.

CONCLUSION

Most cancer patients with EOL care continue to receive antibiotics until just before their death. A careful approach is needed, considering the benefits and side effects of antibiotic use, and the patient's right to self-decision. It is necessary to actively improve awareness of ASP and its importance for medical staff.

Postoperative infectious complications are associated with diminished overall survival of patients undergoing resection for colorectal liver metastases

INTRODUCTION

Postoperative infectious complications (PIC) remain one of the most common complications after surgery. The influence of PIC on long-term survival for patients after liver surgery for colorectal liver metastases (CRLM) needs further investigation.

METHODS

Data of patients who underwent liver resection for CRLM between 2012 and 2017 at the Department of Surgery, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin were evaluated. Overall survival (OS) was stratified according to the development of PIC. Independent predictors of PIC and diminished survival were identified using regression models.

RESULTS

Of 270 patients, eighty-four (31%) patients developed PIC including intraabdominal infections (n = 51, 61%), cholangitis (n = 5, 6%), pneumonia (n = 12, 14%), wound infections (n = 28, 33%), urinary tract infections (n = 5, 6%), or central line-associated bloodstream infections (n = 4, 5%). PIC were associated with a significantly diminished five-year OS (30% vs. 43%, p = 0.008). Age >65 years (p = 0.016, hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.2-4.0), comorbidity (p = 0.019, HR [95% CI] = 2.4 [1.2-4.9]), simultaneous resection of primary tumor (p = 0.005, HR [95% CI] = 4.3 [1.6-11.9]), biliary drainage (p < 0.001, HR [95% CI] = 4.1 [2.0-8.5]), and length of procedure ≥272 min (p = 0.012, HR [95% CI] = 2.2 [1.2-4.1]) were independent predictors for the development of PIC. Body-mass index (BMI) > 30 kg/m2 (p = 0.002, HR [95% CI] = 2.4 [1.4-4.0]), postoperative major complications (p = 0.003, HR [95% CI] = 2.2 [1.3-3.8]), and 3- or 4-MRGN bacteria (p = 0.001, HR [95% CI] = 7.7 [2.2-27.3]) were independently associated with diminished OS.

CONCLUSIONS

PIC are associated with diminished OS after resection for CRLM. Age >65 years, comorbidities, simultaneous resection of the primary tumor, and biliary drainages were identified as independent risk factors for the development of PIC. High BMI, postoperative major morbidity and 3-/4-MRGN bacteria were independently predictive of worse OS. These factors need to be considered in perioperative management for patients with CRLM.

Decreasing the incidence of central line-associated bloodstream infection in a medical intensive care unit: a best practice implementation project

INTRODUCTION AND OBJECTIVES

Bloodstream infections are common in critically ill patients using central venous access devices (CVAD) in intensive care units (ICU). This project aimed to decrease the incidence of central line-associated bloodstream infections (CLABSI) by using evidence-based strategies.

METHODS

The project applied the JBI audit and feedback methods. Thirty-two nurses and five resident physicians from the medical ICU of a medical center participated in the project. Preintervention compliance was measured for the 11 key evidence-based criteria (six audit criteria of central venous catheter insertion and five audit criteria of dressing and catheter securement). Strategies were implemented to overcome the barriers identified in the baseline assessment. Impact evaluation and sustainability were conducted to change the CLABSI rate and the competence of healthcare professionals in providing CVAD care. The JBI Practical Application of Clinical Evidence System and Getting Research into Practice audit tools were used for the data collection, analysis, and implementation planning.

RESULTS

Barriers included insufficient knowledge among nurses and physicians, poor compliance with the standard CVAD insertion procedure by physicians, inadequate cooperation among the CVAD care team members, and lack of CVAD-related equipment. The strategies included education and training in CVAD care, the establishment of a team resource management program, and the provision of appropriate equipment. Following project implementation, the CLABSI rate decreased from 8.38 to 3.9 BSIs/1000 CVAD-days.

CONCLUSIONS

The project successfully decreased the CLABSI rate and increased the competence of healthcare professionals. Implementation of best practices in clinical care should focus on leadership, team resource management, education, monitoring, and innovation.

Microorganism colonization of peripheral venous catheters in a small animal clinical setting

OBJECTIVE

To compare the incidence of microorganism colonization of peripheral venous catheters (PVCs) placed in the Emergency Department (ED) to those placed in a routine preoperative setting. The relationship between catheter tip colonization and patient urgency (as assessed by triage priority) was also evaluated.

DESIGN

Prospective, observational study from January 2021 to October 2021.

SETTING

Emergency room and clinical areas of a large, urban, tertiary referral center.

ANIMALS

Three hundred dogs and 94 cats with a PVC in place for a minimum of 24 hours were enrolled in the study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred and eighty-eight PVCs were placed in the ED and 106 were placed preoperatively. The overall colonization rate was 10.4% (41/394). Sixteen bacterial and 1 fungal genera were cultured. Eight of these bacterial genera (25/51 [49%] bacterial isolates) were resistant to at least 1 antimicrobial class. Twenty-nine of 288 (10.1%) catheters positive for colonization were placed in the ED, whereas 12 of 106 (11.3%) were placed preoperatively. There was no association between microorganism growth on catheters and clinical area of catheter placement. There was also no association between ED patient urgency and positive catheter tip culture. No significant risk factors were identified predisposing to colonization of PVCs.

CONCLUSIONS

The overall incidence of microorganism colonization of PVCs in this study population was equivalent to, or lower than, previously reported in veterinary literature. There was no statistical difference between the catheters placed in the ED and those placed for routine surgical procedures. Patient urgency did not affect the incidence of positivity of peripheral catheter tip cultures.

Metastatic methicillin-resistant Staphylococcus aureus infection with infective endocarditis, pulmonary septic emboli, axillary abscess with a subacute presentation in a patient with chronic end-stage kidney disease on maintenance haemodialysis

A male adult patient on maintenance haemodialysis due to end-stage diabetic nephropathy presented with low-grade intermittent fever, cough and generalised weakness for 3 weeks. Initial blood investigations revealed an elevated neutrophil count with raised inflammatory markers. Chest CT revealed loculated hydropneumothorax with multiple cavitary nodules. Repeated blood cultures from the cuffed tunnelled catheter site and the right arm and sputum cultures were negative for pyogenic bacteria and yeast aetiology. The patient complained about left axillary pain on the fourth day of admission. Ultrasound-guided percutaneous aspiration from an axillary focal collection and subsequent culture revealed a methicillin-resistant Staphylococcus aureus (MRSA) infection. Echocardiography detected multiple vegetations on the tricuspid valve. The patient responded clinically to vancomycin and removal of the permanent catheter. This was a case of a tunnelled catheter-related metastatic MRSA infection with infective endocarditis, pulmonary septic embolism with a subacute presentation, and repeated blood culture negativity.

Effect of indwelling depth of peripheral intravenous catheters on thrombophlebitis

To clarify the effect of catheter indwelling depth on the occurrence of thrombophlebitis, a total of 339 hospitalized patients were randomly enrolled and divided by the catheter indwelling depth into 2 groups. Then the effect of indwelling depth on thrombophlebitis was analyzed, and the independent influence factors on the occurrence of thrombophlebitis were clarified. There were 49 cases of thrombophlebitis, including 8 tumor-bearing patients and 41 patients with lung infection. Thirteen of the 135 patients with indwelling depth of 1 cm, and 36 of the 204 patients with indwelling depth of 1.9 cm suffered thrombophlebitis. The relationship between incidence rate of thrombophlebitis and clinicopathological parameters was analyzed. It was found the incidence of thrombophlebitis was significantly correlated with males (X2 = 5.77), lung infection (X2 = 7.79), and indwelling depth of 1.9 cm (X2 = 4.223). Multifactor analysis of variance showed the significant independent risk factors of thrombophlebitis were male [hazard ratio (HR) 3.12 (1.39-6.98)], and lung infection (HR 0.22 [0.06-0.69]), and the indwelling depth of 1.9 cm affected the occurrence of thrombophlebitis (HR 0.79 [0.42 -3.09]) but was not an independent risk factor. In our treatment center, while appropriate fixation was ensured, the catheter indwelling depth shall be as short as possible, so as to reduce the occurrence of thrombophlebitis. For patients with lung infection, nursing at the intubation site shall be strengthened, so as to decrease thrombophlebitis.

Rapid Identification of Pathogens Causing Bloodstream Infections by Raman Spectroscopy and Raman Tweezers

The search for the "Holy Grail" in clinical diagnostic microbiology-a reliable, accurate, low-cost, real-time, easy-to-use method-has brought up several methods with the potential to meet these criteria. One is Raman spectroscopy, an optical, nondestructive method based on the inelastic scattering of monochromatic light. The current study focuses on the possible use of Raman spectroscopy for identifying microbes causing severe, often life-threatening bloodstream infections. We included 305 microbial strains of 28 species acting as causative agents of bloodstream infections. Raman spectroscopy identified the strains from grown colonies, with 2.8% and 7% incorrectly identified strains using the support vector machine algorithm based on centered and uncentred principal-component analyses, respectively. We combined Raman spectroscopy with optical tweezers to speed up the process and captured and analyzed microbes directly from spiked human serum. The pilot study suggests that it is possible to capture individual microbial cells from human serum and characterize them by Raman spectroscopy with notable differences among different species. IMPORTANCE Bloodstream infections are among the most common causes of hospitalizations and are often life-threatening. To establish an effective therapy for a patient, the timely identification of the causative agent and characterization of its antimicrobial susceptibility and resistance profiles are essential. Therefore, our multidisciplinary team of microbiologists and physicists presents a method that reliably, rapidly, and inexpensively identifies pathogens causing bloodstream infections-Raman spectroscopy. We believe that it might become a valuable diagnostic tool in the future. Combined with optical trapping, it offers a new approach where the microorganisms are individually trapped in a noncontact way by optical tweezers and investigated by Raman spectroscopy directly in a liquid sample. Together with the automatic processing of measured Raman spectra and comparison with a database of microorganisms, it makes the whole identification process almost real time.

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.

Antiseptic solutions for skin preparation during central catheter insertion in neonates

BACKGROUND

Central venous catheters (CVC) are associated with potentially dangerous complications such as thromboses, pericardial effusions, extravasation, and infections in neonates. Indwelling catheters are amongst the main risk factors for nosocomial infections. The use of skin antiseptics during the preparation for central catheter insertion may prevent catheter-related bloodstream infections (CRBSI) and central line-associated bloodstream infections (CLABSI). However, it is still not clear which antiseptic solution is the best to prevent infection with minimal side effects.

OBJECTIVES

To systematically evaluate the safety and efficacy of different antiseptic solutions in preventing CRBSI and other related outcomes in neonates with CVC.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and trial registries up to 22 April 2022. We checked reference lists of included trials and systematic reviews that related to the intervention or population examined in this Cochrane Review.  SELECTION CRITERIA: Randomised controlled trials (RCTs) or cluster-RCTs were eligible for inclusion in this review if they were performed in the neonatal intensive care unit (NICU), and were comparing any antiseptic solution (single or in combination) against any other type of antiseptic solution or no antiseptic solution or placebo in preparation for central catheter insertion. We excluded cross-over trials and quasi-RCTs.

DATA COLLECTION AND ANALYSIS

We used the standard methods from Cochrane Neonatal. We used the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We included three trials that had two different comparisons: 2% chlorhexidine in 70% isopropyl alcohol (CHG-IPA) versus 10% povidone-iodine (PI) (two trials); and CHG-IPA versus 2% chlorhexidine in aqueous solution (CHG-A) (one trial). A total of 466 neonates from level III NICUs were evaluated. All included trials were at high risk of bias. The certainty of the evidence for the primary and some important secondary outcomes ranged from very low to moderate. There were no included trials that compared antiseptic skin solutions with no antiseptic solution or placebo. CHG-IPA versus 10% PI Compared to PI, CHG-IPA may result in little to no difference in CRBSI (risk ratio (RR) 1.32, 95% confidence interval (CI) 0.53 to 3.25; risk difference (RD) 0.01, 95% CI -0.03 to 0.06; 352 infants, 2 trials, low-certainty evidence) and all-cause mortality (RR 0.88, 95% CI 0.46 to 1.68; RD -0.01, 95% CI -0.08 to 0.06; 304 infants, 1 trial, low-certainty evidence). The evidence is very uncertain about the effect of CHG-IPA on CLABSI (RR 1.00, 95% CI 0.07 to 15.08; RD 0.00, 95% CI -0.11 to 0.11; 48 infants, 1 trial; very low-certainty evidence) and chemical burns (RR 1.04, 95% CI 0.24 to 4.48; RD 0.00, 95% CI -0.03 to 0.03; 352 infants, 2 trials, very low-certainty evidence), compared to PI. Based on a single trial, infants receiving CHG-IPA appeared less likely to develop thyroid dysfunction compared to PI (RR 0.05, 95% CI 0.00 to 0.85; RD -0.06, 95% CI -0.10 to -0.02; number needed to treat for an additional harmful outcome (NNTH) 17, 95% CI 10 to 50; 304 infants). Neither of the two included trials assessed the outcome of premature central line removal or the proportion of infants or catheters with exit-site infection. CHG-IPA versus CHG-A The evidence suggests CHG-IPA may result in little to no difference in the rate of proven CRBSI when applied on the skin of neonates prior to central line insertion (RR 0.80, 95% CI 0.34 to 1.87; RD -0.05, 95% CI -0.22 to 0.13; 106 infants, 1 trial, low-certainty evidence) and CLABSI (RR 1.14, 95% CI 0.34 to 3.84; RD 0.02, 95% CI -0.12 to 0.15; 106 infants, 1 trial, low-certainty evidence), compared to CHG-A. Compared to CHG-A, CHG-IPA probably results in little to no difference in premature catheter removal (RR 0.91, 95% CI 0.26 to 3.19; RD -0.01, 95% CI -0.15 to 0.13; 106 infants, 1 trial, moderate-certainty evidence) and chemical burns (RR 0.98, 95% CI 0.47 to 2.03; RD -0.01, 95% CI -0.20 to 0.18; 114 infants, 1 trial, moderate-certainty evidence). No trial assessed the outcome of all-cause mortality and the proportion of infants or catheters with exit-site infection.

AUTHORS' CONCLUSIONS

Based on current evidence, compared to PI, CHG-IPA may result in little to no difference in CRBSI and mortality. The evidence is very uncertain about the effect of CHG-IPA on CLABSI and chemical burns. One trial showed a statistically significant increase in thyroid dysfunction with the use of PI compared to CHG-IPA. The evidence suggests CHG-IPA may result in little to no difference in the rate of proven CRBSI and CLABSI when applied on the skin of neonates prior to central line insertion. Compared to CHG-A, CHG-IPA probably results in little to no difference in chemical burns and premature catheter removal. Further trials that compare different antiseptic solutions are required, especially in low- and middle-income countries, before stronger conclusions can be made.

Randomized clinical trial: Long-term Staphylococcus aureus decolonization in patients on home parenteral nutrition

BACKGROUND & AIMS

Staphylococcus aureus decolonization has proven successful in prevention of S. aureus infections and is a key strategy to maintain venous access and avoid hospitalization in patients receiving home parenteral nutrition (HPN). We aimed to determine the most effective and safe long-term S. aureus decolonization regimen.

METHODS

A randomized, open-label, multicenter clinical trial was conducted. Adult intestinal failure patients with HPN support and carrying S. aureus were randomly assigned to a 'continuous suppression' (CS) strategy, a repeated chronic topical antibiotic treatment or a 'search and destroy' (SD) strategy, a short and systemic antibiotic treatment. Primary outcome was the proportion of patients in whom S. aureus was totally eradicated during a 1-year period. Secondary outcomes included risk factors for decolonization failure and S. aureus infections, antimicrobial resistance, adverse events, patient compliance and cost-effectivity.

RESULTS

63 participants were included (CS 31; SD 32). The mean 1-year S. aureus decolonization rate was 61% (95% CI 44, 75) for the CS group and 39% (95% CI 25, 56) for the SD group with an OR of 2.38 (95% CI 0.92, 6.11, P = 0.07). More adverse effects occurred in the SD group (P = 0.01). Predictors for eradication failure were a S. aureus positive caregiver and presence of a (gastro)enterostomy.

CONCLUSION

We did not demonstrate an increased efficacy of a short and systemic S. aureus decolonization strategy over a continuous topical suppression treatment. The latter may be the best option for HPN patients as it achieved a higher long-term decolonization rate and was well-tolerated (NCT03173053).

Incidence and short-term outcomes of central line-related bloodstream infection in patients admitted to the emergency department: a single-center retrospective study

Central line-related bloodstream infection (CRBSI) is a common complication during hospital admissions; however, there is insufficient data regarding CRBSI in the emergency department. Therefore, we evaluated the incidence and clinical impact of CRBSI using a single-center retrospective study to analyze medical data of 2189 adult patients (median age: 65 years, 58.8% males) who underwent central line insertion in ED from 2013 to 2015. CRBSI was defined if the same pathogens were identified at peripheral and catheter tips or the differential time to positivity was > 2 h. CRBSI-related in-hospital mortality and risk factors were evaluated. CRBSI occurred in 80 patients (3.7%), of which 51 survived and 29 died; those with CRBSI had higher incidence of subclavian vein insertion and retry rates. Staphylococcus epidermidis was the most common pathogen, followed by Staphylococcus aureus, Enterococcus faecium, and Escherichia coli. Using multivariate analysis, we found that CRBSI development was an independent risk factor for in-hospital mortality (adjusted odds ratio: 1.93, 95% confidence intervals: 1.19-3.14, p < 0.01). Our findings suggest that CRBSI after central line insertion in the emergency department is common and associated with poor outcomes. Infection prevention and management measures to reduce CRBSI incidence are essential to improve clinical outcomes.

Multicentre surveillance of epidemiologically important pathogens causing nosocomial bloodstream infections and pneumonia trials in Brazilian adult intensive care units

Introduction. Healthcare-associated infections (HAIs) are the most recurrent adverse event in hospitals worldwide and represent an important public health problem.Gap statement. There are a paucity of multicentric data describing severe HAIs such as bloodstream infection (BSI) and pneumonia in Brazil.Aim. To provide an up-to-date picture of the extent and patterns of HAIs in adult intensive care units (ICUs), as well as to identify variables associated with the risk of development of severe infections.Methodology. Point prevalence surveys were conducted using standardized protocols in 35 ICUs from Minas Gerais state, Brazil. Medical records of eligible inpatients at or before 8 am on the survey day were reviewed to identify HAIs present at the time of the survey. A matched-pairs case-control study was performed on a total of 66 pairs for BSI and 115 pairs for pneumonia according to the selection criteria developed.Results. Overall, 171 patients (45.7%) had at least one HAI, with most (78.4%) acquired in the ICU. These patients presented a total of 240 infections; including 123 pneumonia (51.3%) and 66 BSI (27.5%), and 78.9 and 80.3 %, respectively, were acquired in the ICU. Their aetiology showed a predominance of Gram-negative bacteria versus Gram-positive bacteria (48.9 versus 43.3 %), with Acinetobacter baumannii (13.7%) and Pseudomonas aeruginosa (12.8%) being prominent. One striking observation from our data was the higher prevalence of Staphylococcus aureus (14.5%) and coagulase-negative staphylococci (10.2%) observed in the overall HAIs.Conclusion. A high severe ICU-acquired HAI burden was found when compared with findings from other low- and middle-income countries. These data can be utilized for better planning of nosocomial infection surveillance programmes in our hospitals.

Pulmonary hypertension at admission predicts ICU mortality in elderly critically ill with severe COVID-19 pneumonia: retrospective cohort study

BACKGROUND

Point-of-care ultrasound (POCUS) is a useful diagnostic tool for non-invasive assessment of critically ill patients. Mortality of elderly patients with COVID-19 pneumonia is high and there is still scarcity of definitive predictors. Aim of our study was to assess the prediction value of combined lung and heart POCUS data on mortality of elderly critically ill patients with severe COVID-19 pneumonia.

METHODS

This was a retrospective observational study. Data of patients older than 70 years, with severe COVID-19 pneumonia admitted to mixed 25-bed, level 3, intensive care unit (ICU) was analyzed retrospectively. POCUS was performed at admission; our parameters of interest were pulmonary artery systolic pressure (PASP) and presence of diffuse B-line pattern (B-pattern) on lung ultrasound.

RESULTS

Between October 2020 and March 2021, 117 patients aged 70 years or more (average age 77 ± 5 years) were included. Average length of ICU stay was 10.7 ± 8.9 days. High-flow oxygenation, non-invasive ventilation and invasive mechanical ventilation were at some point used to support 36/117 (31%), 39/117 (33%) and 75/117 (64%) patients respectively. ICU mortality was 50.9%. ICU stay was shorter in survivors (8.8 ± 8.3 vs 12.6 ± 9.3 days, p = 0.02). PASP was lower in ICU survivors (32.5 ± 9.8 vs. 40.4 ± 14.3 mmHg, p = 0.024). B-pattern was more often detected in non-survivors (35/59 (59%) vs. 19/58 (33%), p = 0.005). PASP and B-pattern at admission, and also mechanical ventilation and development of VAP, were univariate predictors of mortality. PASP at admission was an independent predictor of ICU (OR 1.061, 95%CI 1.003-1.124, p = 0.039) and hospital (OR 1.073, 95%CI 1.003-1.146, p = 0.039) mortality.

CONCLUSIONS

Pulmonary artery systolic pressure at admission is an independent predictor of ICU and hospital mortality of elderly patients with severe COVID-19 pneumonia.

The predictors of catheter-related bloodstream infections in patients undergoing hemodialysis: A single center experience

BACKGROUND

Here we aimed to investigate the predictors of catheter-related bloodstream infections (CRBSI) in patients with acute kidney injury or chronic kidney disease who required renal replacement therapy through a non-tunneled hemodialysis catheter.

METHODS

A total of 111 patients who received non-tunneled hemodialysis catheters were retrospectively evaluated. Patients were divided into two groups; those who developed CRBSI and those who did not. Patient's demographic data, laboratory results at admission, information regarding catheter infections, and culture results were obtained from electronic medical records.

RESULTS

The mean age of the patients was 64 ± 16 years, and 51 of them were male. CRBSI occurred in 14 patients (12.6%). Admission serum albumin level (OR: 0.119, 95% CI: 0.019-0.756, p = 0.024), admission mean platelet volume (OR: 2.207, 95% CI: 1.188-4.100, p = 0.012) and catheter duration (OR: 1.580, 95% CI: 1.210-2.064, p = 0.001) were independent predictors for the CRBSI development. ROC curve analysis demonstrated that a catheter duration of 22 days was predictive for presence of CRBSI (78% sensitivity, 76% specificity, AUC: 0.825, 95% CI: 0.724-0.925, p < 0.001).

CONCLUSIONS

Prolonged catheter duration, low serum albumin, and high mean platelet volume independently predict the development of CRBSI in patients undergoing hemodialysis for acute kidney injury or chronic kidney disease.

Crystal violet-based assay for the assessment of bacterial biofilm formation in medical tubing

Crystal violet-based assay is widely used to evaluate the early stages of bacterial biofilm formation. Here, we modified it to study biofilm formation in medical tubing. While cost-effective and requiring no sophisticated equipment, our method provided quantitative and qualitative distinctions between the ability of four bacterial strains to colonize PVC catheters.

Design of Thermoplastic Polyurethanes with Conferred Antibacterial, Mechanical, and Cytotoxic Properties for Catheter Application

Thermoplastic polyurethanes (TPUs) are proposed as suitable solution for the fabrication of biocompatible catheters with appropriate mechanical parameters and confirmed antibacterial and cytocompatible properties. For this purpose, a series of quaternary ammonium salts (QASs) and quaternary phosphonium salts (QPSs) based monomers were prepared followed by the determination of their minimal inhibitory concentrations (MICs) against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Pseudomonas aeruginosa (P. aeruginosa). A combination of the most active ammonium (QAS-C₁₄) and phosphonium (QPS-TOP) salts led to a MIC down to 2.4 μg/mL against S. aureus and 9 μg/mL against P. aeruginosa, corroborating the existence of a synergistic effect. These quaternary onium salt (QOS) units were successfully incorporated along the polymer chain, as part of a two-step synthesis approach. The resulting TPU-QOS materials were subsequently characterized through thermal, mechanical, and surface analyses. TPU-Mix (combining the most active QAS-C₁₄ and QPS-TOP units) showed the highest antibacterial efficiency, confirming the synergistic effect between both QOS groups. Finally, an MTT assay on the SiHa cell line revealed the low cytotoxicity level of these polymeric films, making these materials suitable for biomedical application. To go one step further in the preindustrialization approach, proof of concept regarding the catheter prototype fabrication based on TPU-QAS/QPS was validated by extrusion.

The comparative accuracy of pooled vs. individual blood culture sampling methods for diagnosis of catheter-related bloodstream infection

Background

Catheter-related bloodstream infection (CRBSI) is associated with increased morbidity, mortality, and cost of treatment in critically ill patients. A differential time to positivity (DTP) of 120 min or more between blood cultures obtained through the catheter vs. peripheral vein is an indicator of CRBSI with high sensitivity and specificity. However, it is no clear whether pooled sampling would be as efficient as individual sampling in order to reduce costs, contamination, or anemia.

Methods

This was a prospective diagnostic study conducted at the medical ICU and semi-ICU of Khon Kaen University’s Srinagarind Hospital in Thailand from May 2020 to November 2021. Fifty patients with triple-lumen central venous catheters (CVCs) who were clinically suspected of CRBSI were enrolled. 15 mL of blood was drawn through each catheter lumen, 10 mL of which was inoculated into three blood culture bottles, and the remaining 5 mL was pooled into a single bottle. Sensitivity, specificity, accuracy, and time to positivity of the pooled blood cultures were calculated using individual blood cultures as a reference.

Results

Of the 50 patients enrolled, 14 (28%) were diagnosed with CRBSI, 57.9% of whom were infected with gram-negative bacteria as the causative pathogen (57.9%). Extensively drug-resistant (XDR) Klebsiella pneumoniae was the most common organism. Sensitivity and specificity of the pooled blood sampling method were 69.23% (95% CI [0.44–0.94]) and 97.3% (95% CI [0.92–1.02]), respectively. The area under the ROC curve (AUC) was 0.83 (95% CI [0.68–0.99]). A paired T-Test to compare time to positivity of the pooled blood bottle and the first positive culture from the individual bottles indicated statistical significance (14.9 and 12.4 h, respectively). The mean difference was 2.5 [0.9–4.1] h, with a 95% CI and a p-value of 0.006.

Conclusion

Pooled blood sampling results in a lower sensitivity and longer time to positivity for CRBSI diagnosis in patients with triple-lumen CVCs than individual lumen sampling.

Trial registration Retrospectively registered at Thai Clinical Trials Registry. The study was reviewed and approved on 08/03/2022. TCTR identification number is TCTR20220308002

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07605-x.