The impact of hospital-acquired bloodstream infections

Evaluation of Sequential Oral Versus Intravenous Antibiotic Treatment of Enterococcus faecalis Bloodstream Infections

BACKGROUND

Intravenous (IV) antibiotics have historically been considered standard of care for treatment of bloodstream infections (BSIs). Recent literature has shown sequential oral (PO) therapy to be noninferior to IV antibiotics for certain pathogens and disease states. However, a gap exists in the literature for BSI caused by Enterococcus faecalis.

OBJECTIVE

To compare outcomes of definitive sequential PO therapy to definitive IV therapy in patients with E faecalis BSI.

METHODS

Multicenter, retrospective, matched cohort study of adult patients with at least one blood culture positive for E faecalis from January 2017 to November 2022. Patients with polymicrobial BSI, concomitant infections requiring prolonged IV antibiotic therapy, those who did not receive antibiotic therapy, and those who died within 72 hours of index culture were excluded. Subjects were matched based on source of infection in a 2:1 (IV:PO) ratio. The primary outcome was a composite of all-cause mortality and treatment failure. Secondary outcomes included hospital length of stay (LOS), antibiotic duration, and 30-day readmission rate.

RESULTS

Of the 186 patients who met criteria for inclusion, there was no statistically significant difference in the primary composite outcome for PO compared to IV therapy (14.5% vs 21.8%; OR 0.53 [0.23-1.25]) or 30-day readmission (17.5% vs 29%; OR 0.53 [0.25-1.13]). Hospital LOS was significantly longer in patients receiving IV-only therapy (6 days vs 14 days; P < 0.001).

CONCLUSION AND RELEVANCE

Sequential oral therapy for E faecalis BSI had similar outcomes compared to IV-only treatment and may be considered in eligible patients.

Synergistic Effect of Thymol-Ciprofloxacin Combination on Planktonic Cells and Biofilm of Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic bacteria causing severe and life-threatening infections in individuals with weakened immune systems. P. aeruginosa forms antibiotic-resistant biofilms, rendering it challenging to treat; hence, alternate therapies are required to eliminate it. Treatment of infections using a combination of drugs is gaining momentum to combat drug-resistant pathogens, including P. aeruginosa. This study explores the synergistic effects of Thymol in combination with Ciprofloxacin, Amikacin and Colistin against planktonic cells and biofilm of P. aeruginosa. Thymol in combination with Ciprofloxacin yields the fractional inhibitory concentration index values 0.156 and 0.375 in P. aeruginosa strains, GC14 and ATCC 9027, respectively, highlighting a robust synergistic effect on both the planktonic and biofilm of P. aeruginosa. The results showed that Thymol (512 μg/mL) and Ciprofloxacin (0.125 μg/mL) were the most effective combination with 95 and 93.5% total biofilm inhibition in GC14 and PA27, respectively, compared to the Thymol (512 μg/mL) and Ciprofloxacin (0.125 μg/mL) alone. Our findings suggest that the combinations of Thymol and Ciprofloxacin may be a potential therapeutic strategy to address the issue of infections caused by P. aeruginosa biofilms.

Preventing nosocomial bloodstream infections (NBSIs) by implementing hospitalwide, department-level, self-investigations: A NBSIs frontline ownership intervention

BACKGROUND

Nosocomial bloodstream infections (NBSIs) are adverse complications of hospitalization. Most interventions focus on intensive care units. Data on interventions involving patients' personal care providers in hospitalwide settings are limited.

OBJECTIVE

To evaluate the impact of department-level NBSI investigations on infection incidence.

METHODS

Beginning in 2016, positive cultures, classified as suspected of being hospital acquired, were prospectively investigated by patients' unit-based personal healthcare providers using a structured electronic questionnaire. After analyzing the conclusions of the investigation, a summary was sent quarterly to the departments and to hospital management. NBSI rates and clinical data during a 5-year period (2014-2018) were calculated and compared before and after the intervention (2014-2015 versus 2016-2018), using interrupted time-series analysis.

RESULTS

Among 4,135 bloodstream infections (BSIs), 1,237 (30%) were nosocomial. The rate of NBSI decreased from 4.58 per 1,000 admissions days in 2014 and 4.82 in 2015, to 3.81 in 2016, 2.94 in 2017 and 2.86 in 2018. Following a 4-month lag after introducing the intervention, the NBSI rate per 1000 admissions dropped significantly by 1.33 (P = .04; 95% CI, -2.58 to -0.07). The monthly NBSI rate continued to decrease significantly by 0.03 during the intervention period (P = .03; 95% CI, -0.06 to -0.002).

CONCLUSIONS

Detailed department-level investigations of NBSI events performed by healthcare providers, increased staff awareness and frontline ownership and were associated with a decrease in NBSI rates hospitalwide.

Incidence, Clinical Features, and Association with Prognosis of Bloodstream Infection in Pediatric Patients After Percutaneous or Surgical Treatment for Ventricular Septal Defect or Atrial Septal Defect: A Retrospective Cohort Study

INTRODUCTION

Bloodstream infection (BSI) may occur after cardiac procedures, but this has rarely been investigated specifically in pediatric patients after percutaneous or surgical treatment for ventricular septal defect (VSD) or atrial septal defect (ASD) with recent data. The current study aimed to investigate the incidence, clinical features, and association with prognosis of BSI in this patient population.

METHODS

Pediatric patients who received percutaneous or surgical procedure for VSD or ASD between 2010 and 2018 in a large children's hospital in China were retrospectively enrolled via the Pediatric Intensive Care database, but only those who had blood culture records within 24 h after the procedure and who had no prior positive blood culture records were included. BSI after the procedure was identified by reviewing blood culture records, and baseline characteristics associated with BSI were explored by univariable logistic regression. In-hospital mortality and length of hospitalization were studied as prognostic outcomes and compared between patients with and without BSI.

RESULTS

A total of 1340 pediatric patients were included. Among them, 46 (3.43%) patients had BSI within 24 h after the procedure, of which the majority (78.26%, 36/46) were caused by Gram-positive bacteria and 65.22% (30/46) had antibiotic-resistant organisms. Age [odds ratio (OR) 0.98 per 1-month increase, 95% confidence interval (CI) 0.97-1.00, P = 0.021] and antibiotic use within 72 h before the procedure (OR 1.81, 95% CI 1.00-3.26, P = 0.049) were statistically significantly associated with developing BSI. Compared with patients without BSI, there was no statistically significant difference in in-hospital mortality (0.00% versus 0.54%, P = 1.000), but patients with BSI had statistically significantly longer length of hospitalization (median 14.51 versus 12.94 days, P = 0.006), while the association was not statistically significant after adjustment for baseline characteristics by multivariable linear regression (β = 1.73, 95% CI -0.59 to 4.04, P = 0.144).

CONCLUSION

BSI is relatively uncommon in pediatric patients after procedures for VSD or ASD, but a younger age seems a risk factor. Developing BSI appears to be associated with increased length of hospitalization but not in-hospital mortality.

Synthetic Glycans to Improve Current Glycoconjugate Vaccines and Fight Antimicrobial Resistance

Antimicrobial resistance (AMR) is emerging as the next potential pandemic. Different microorganisms, including the bacteria Acinetobacter baumannii, Clostridioides difficile, Escherichia coli, Enterococcus faecium, Klebsiella pneumoniae, Neisseria gonorrhoeae, Pseudomonas aeruginosa, non-typhoidal Salmonella, and Staphylococcus aureus, and the fungus Candida auris, have been identified by the WHO and CDC as urgent or serious AMR threats. Others, such as group A and B Streptococci, are classified as concerning threats. Glycoconjugate vaccines have been demonstrated to be an efficacious and cost-effective measure to combat infections against Haemophilus influenzae, Neisseria meningitis, Streptococcus pneumoniae, and, more recently, Salmonella typhi. Recent times have seen enormous progress in methodologies for the assembly of complex glycans and glycoconjugates, with developments in synthetic, chemoenzymatic, and glycoengineering methodologies. This review analyzes the advancement of glycoconjugate vaccines based on synthetic carbohydrates to improve existing vaccines and identify novel candidates to combat AMR. Through this literature survey we built an overview of structure-immunogenicity relationships from available data and identify gaps and areas for further research to better exploit the peculiar role of carbohydrates as vaccine targets and create the next generation of synthetic carbohydrate-based vaccines.

Errors in Antimicrobial Prescription and Administration in Very Low Birth Weight Neonates at a Tertiary South African Hospital

BACKGROUND

Antimicrobial prescription and administration-related errors occur frequently in very low birth weight (VLBW; <1,500 g) neonates treated for bloodstream infections (BSI).

METHODS

Antimicrobial prescriptions for the treatment of laboratory-confirmed BSI were retrospectively analyzed for VLBW neonates at Tygerberg Hospital, Cape Town, South Africa (1 July 2018 - 31 December 2019), describing antimicrobial type, indication, duration of therapy and BSI outcomes. The prevalence of, and risk factors for prescription (dose, interval) and administration errors (hang-time, delayed/missed doses) were determined.

RESULTS

One hundred and sixty-one BSI episodes [16 (9.9%)] early-onset, 145 [90.1%] healthcare-associated) affected 141 neonates (55% male, 25% born to mothers living with HIV, 46% <1,000 g birth weight) with 525 antimicrobial prescription episodes [median 3.0 (IQR 2-4) prescriptions/BSI episode]. The median duration of therapy for primary BSI, BSI-associated with meningitis and BSI-associated with surgical infections was 9, 22, and 28 days, respectively. The prevalence of dose and dosing interval errors was 15.6% (77/495) and 16.4% (81/495), respectively with prescription errors occurring most commonly for piperacillin-tazobactam and vancomycin given empirically. Administration errors were less frequent [3.8% (219/5,770) doses missed; 1.4% (78/5,770) delayed], however 64% had a hang-time (time from sepsis diagnosis to 1st dose of antimicrobial) exceeding 60 min. On multivariable analysis, postnatal age >7 days was associated with prescription errors (p = 0.028). The majority of neonates with BSI required escalation of respiratory support (52%) and 26% required intensive care admission. Despite fair concordance between empiric antimicrobial/s prescription and pathogen susceptibility (74.5%), BSI-attributable mortality in this cohort was 30.4%.

CONCLUSION

VLBW neonates with BSI's were critically ill and had high mortality rates. Hang-time to first antimicrobial administration was delayed in two-thirds of BSI episodes and prescription errors affected almost 1 in 6 prescriptions. Targets for intervention should include reducing hang-time, use of standardized antimicrobial dosing guidelines and implementation of antimicrobial stewardship recommendations.

Pseudomonas aeruginosa Biofilm Formation and Its Control

Microbes are hardly seen as planktonic species and are most commonly found as biofilm communities in cases of chronic infections. Biofilms are regarded as a biological condition, where a large group of microorganisms gets adhered to a biotic or abiotic surface. In this context, Pseudomonas aeruginosa, a Gram-negative nosocomial pathogen is the main causative organism responsible for life-threatening and persistent infections in individuals affected with cystic fibrosis and other lung ailments. The bacteria can form a strong biofilm structure when it adheres to a surface suitable for the development of a biofilm matrix. These bacterial biofilms pose higher natural resistance to conventional antibiotic therapy due to their multiple tolerance mechanisms. This prevailing condition has led to an increasing rate of treatment failures associated with P. aeruginosa biofilm infections. A better understanding of the effect of a diverse group of antibiotics on established biofilms would be necessary to avoid inappropriate treatment strategies. Hence, the search for other alternative strategies as effective biofilm treatment options has become a growing area of research. The current review aims to give an overview of the mechanisms governing biofilm formation and the different strategies employed so far in the control of biofilm infections caused by P. aeruginosa. Moreover, this review can also help researchers to search for new antibiofilm agents to tackle the effect of biofilm infections that are currently imprudent to conventional antibiotics.

Effectiveness of Oxalis corniculata L. Ethanol Extract against Mono-Species of Biofilm Staphylococcus aureus

Inappropriate administration of antibiotics can cause resistance to bacteria. Staphylococcus aureus is one of the strong biofilm-forming bacteria that cause antibiotic resistance. Calincing (Oxalis corniculata L.) leaves have excellent antibacterial activity, but their antibiofilm activity against S. aureus has not been reported until now. Currently, the discovery of new antibiofilm against S. aureus biofilms is significant to prevent the impact of infections caused by biofilms. This study was intended to determine the effectiveness of the ethanol extract of O. corniculata leaves in inhibiting and eradicating S. aureus biofilm formation. Planktonic testing, inhibition, and biofilm eradication activity were carried out using the microtiter broth method. Antibiofilm activity of O. corniculata leaves against S. aureus biofilm was analyzed by calculating the minimum concentration of biofilm inhibitor (MBIC50) and minimum biofilm eradication concentration (MBEC50). Data were analyzed using the Statistical Package for the Social Sciences (SPSS) with a 95% confidence level. Oxalis corniculata leaves showed inhibitory activity on the formation of the tested S. aureus biofilm. The ethanol extract of 1% O. corniculata leaves gave 76.23±0.01% antibacterial activity of S. aureus and 71.32±0.01% of mid-phase antibiofilm activity, and 69.33±0.01% maturation phase. The results also prove that the ethanolic extract of O. corniculata leaves can eradicate S. aureus biofilm formation. Therefore, the ethanol extract of O. corniculata leaves can be developed as a new antibiofilm against S. aureus.

Monophosphoryl Lipid a Attenuates Multiorgan Dysfunction During Post-Burn Pseudomonas Aeruginosa Pneumonia in Sheep

BACKGROUND

Monophosphoryl lipid A (MPLA) is a TLR4 agonist that has potent immunomodulatory properties and modulates innate immune function to improve host resistance to infection with common nosocomial pathogens in mice. The goal of this study was to assess the safety and efficacy of MPLA in a sheep model of burn injury and Pseudomonas aeruginosa pneumonia. The sheep provides a favorable model for preclinical testing as their response to TLR4 agonists closely mimics that of humans.

METHODS

Twelve chronically instrumented adult female Merino sheep received 20% total body surface area, third-degree cutaneous burn under anesthesia and analgesia. At 24 h after burn, sheep were randomly allocated to receive: MPLA (2.5 μg/kg i.v., n = 6), or vehicle (i.v., n = 6). At 24 h after MPLA or vehicle treatment, Pseudomonas aeruginosa pneumonia was induced. Sheep were mechanically ventilated, fluid resuscitated and cardiopulmonary variables were monitored for 24 h after induction of pneumonia. Cytokine production, vascular barrier function, and lung bacterial burden were also measured.

RESULTS

MPLA infusion induced small and transient alterations in core body temperature, heart rate, pulmonary artery pressure, and pulmonary vascular resistance. Pulmonary mechanics were not altered. Vehicle-treated sheep developed severe acute lung injury during Pseudomonas aeruginosa pneumonia, which was attenuated by MPLA as indicated by improved PaO2/FiO2 ratio, oxygenation index, and shunt fraction. Sheep treated with MPLA also exhibited less vascular leak, lower blood lactate levels, and lower modified organ injury score. MPLA treatment attenuated systemic cytokine production and decreased lung bacterial burden.

CONCLUSIONS

MPLA was well tolerated in burned sheep and attenuated development of acute lung injury, lactatemia, cytokinemia, vascular leak, and hemodynamic changes caused by Pseudomonas aeruginosa pneumonia.

Comparison of blood cultures versus T2 Candida Panel in management of candidemia at a large community hospital

The T2 Candida Panel (T2CP) has high sensitivity and specificity to detect candidemia. Its role in the diagnosis and management of candidemia compared to blood cultures (BC) remains unclear. The purpose of this study was to evaluate the T2CP versus BC in detecting and treating candidemia. A retrospective, observational cohort study was conducted to compare clinical outcomes in patients with candidemia identified by BC versus T2CP. Patients with a positive BC or T2CP for Candida spp. from January 2012 to August 2020 were grouped by initial method of detection (BC vs T2CP). Co-primary endpoints assessed included time to detection of candidemia and time to antifungal therapy. Key secondary endpoints included length of stay (LOS), ICU LOS, and mortality. One hundred sixty-three patients with a positive BC and 89 patients with a positive T2CP were included in the evaluation. The average time to detection of candidemia was significantly shorter in the T2CP group compared to BC group (9 vs 41 h, p < 0.001). The time to antifungal was also significantly shorter in the T2CP group compared to the BC group (4 vs 37 h, p < 0.001). However, LOS was significantly shorter in the BC positive group than the T2CP group with no difference in ICU LOS. There was no difference in in-hospital or 30-day mortality between the two groups. Of patients diagnosed with candidemia at our large community hospital, identification by T2CP led to faster detection and initiation of antifungal compared to blood cultures without improvement in LOS or mortality.

MSG-10: a Phase 2 study of oral ibrexafungerp (SCY-078) following initial echinocandin therapy in non-neutropenic patients with invasive candidiasis

OBJECTIVES

To evaluate the safety and efficacy of two dosing regimens of oral ibrexafungerp (formerly SCY-078), a novel orally bioavailable β-glucan synthase inhibitor, in subjects with invasive candidiasis versus the standard of care (SOC) and to identify the dose to achieve target exposure (15.4 μM·h) in >80% of the intended population.

METHODS

In a multinational, open-label study, patients with documented invasive candidiasis were randomized to receive step-down therapy to one of three treatment arms: two dosing regimens of novel oral ibrexafungerp or the SOC treatment following initial echinocandin therapy. Plasma samples were collected to evaluate exposure by population pharmacokinetic (PK) modelling. Safety was assessed throughout the study and global response at the end of treatment.

RESULTS

Out of 27 subjects enrolled, 7 received ibrexafungerp 500 mg, 7 received ibrexafungerp 750 mg and 8 received the SOC. Five did not meet criteria for randomization. Population PK analysis indicated that an ibrexafungerp 750 mg regimen is predicted to achieve the target exposure in ∼85% of the population. The rate of adverse events was similar among patients receiving ibrexafungerp or fluconazole. Similar favourable response rates were reported among all groups: 86% (n = 6) in the ibrexafungerp 750 mg versus 71% (n = 5) in both the fluconazole and ibrexafungerp 500 mg treatment arms. The one subject treated with continued micafungin had a favourable global response.

CONCLUSIONS

The oral ibrexafungerp dose estimated to achieve the target exposure in subjects with invasive candidiasis is 750 mg daily. This dose was well tolerated and achieved a favourable global response rate, similar to the SOC.

Synthetic Ellagic Acid Glycosides Inhibit Early Stage Adhesion of Streptococcus agalactiae Biofilms as Observed by Scanning Electron Microscopy

Ellagic acid derivatives possess antimicrobial and antibiofilm properties across a wide-range of microbial pathogens. Due to their poor solubility and ambident reactivity it is challenging to synthesize, purify, and characterize the activity of ellagic acid glycosides. In this study, we have synthesized three ellagic acid glycoconjugates and evaluated their antimicrobial and antibiofilm activity in Streptococcus agalactiae (Group B Streptococcus, GBS). Their significant impacts on biofilm formation were examined via SEM to reveal early-stage inhibition of cellular adhesion. Additionally, the synthetic glycosides were evaluated against five of the six ESKAPE pathogens and two fungal pathogens. These studies reveal that the ellagic acid glycosides possess inhibitory effects on the growth of gram-negative pathogens.

Catheter-Associated Urinary Tract Infection, Clostridioides difficile Colitis, Central Line-Associated Bloodstream Infection, and Methicillin-Resistant Staphylococcus aureus

Hospital-acquired infections increase cost, morbidity, and mortality for patients across the United States and the world. Principal among these infections are central line-associated bloodstream infection, catheter-associated urinary tract infection, Clostridioides difficile, and methicillin-resistant Staphylococcus aureus colonization and infections. This article provides succinct summaries of the background, epidemiology, diagnosis, and treatment of these conditions. In addition, novel prevention strategies, including those related to recent national interventions, are reviewed.

Utilization and impact of a rapid Candida panel on antifungal stewardship program within a large community hospital

BACKGROUND

The T2 Candida Panel (T2CP) bodes high sensitivity and specificity to detect candidemia, enabling providers to make quick therapy decisions and possibly decrease mortality. However, utilization in practice and clinical application remains to be evaluated.

OBJECTIVES

To evaluate the overall provider-utilization of the T2CP at a large community hospital.

METHODS

This single center, retrospective, observational study compared antifungal management in all patients with positive or negative T2CP. Additional endpoints included patient-specific variables influencing antifungal management decisions.

RESULTS

Six hundred twenty-eight T2CP results were evaluated. Antifungal optimization occurred in 54% of patients who had antifungal orders at the time of T2CP test. Antifungal therapy was avoided in 60.4% of negative cases. Patients with negative T2CP had significantly fewer days of therapy compared to positive tests.

CONCLUSIONS

Although the T2CP led to fewer days of antifungal therapy with negative tests, many opportunities for improvement in antifungal stewardship were identified, specifically, with negative tests.

Self-Assembled Saccharide-Functionalized Amphiphilic Metallacycles as Biofilms Inhibitor via "Sweet Talking"

Bacterial biofilms are troublesome in the treatment of bacterial infectious diseases due to their inherent resistance to antibiotic therapy. Exploration of alternative antibiofilm reagents provides opportunities to achieve highly effective treatments. Herein, we propose a strategy to employ self-assembled saccharide-functionalized amphiphilic metallacycles ([2+2]-Gal, [3+3]-Gal, and [6+6]-Gal) with multiple positive charges as a different type of antibacterial reagent, marrying saccharide functionalization that interact with bacteria via "sweet talking". These self-assembled glyco-metallacycles gave various nanostructures (nanoparticles, vesicles or micron-sized vesicles) with different biofilms inhibition effect on Staphylococcus aureus (S. aureus). Especially, the peculiar self-assembly mechanism, superior antibacterial effect and biofilms inhibition distinguished the [6+6]-Gal from other metallacycles. Meanwhile, in vivo S. aureus pneumonia animal model experiments suggested that [6+6]-Gal could relieve mice pneumonia aroused by S. aureus effectively. In addition, the control study of metallacycle [3+3]-EG₅ confirmed the significant role of galactoside both in the self-assembly process and the antibacterial efficacy. In view of the superior effect against bacteria, the saccharide-functionalized metallacycle could be a promising candidate as biofilms inhibitor or treatment agent for pneumonia.

The learning hospital: From theory to practice in a hospital infection prevention program

The learning hospital is distinguished by ceaseless evolution of erudition, enhancement, and implementation of clinical best practices. We describe a model for the learning hospital within the framework of a hospital infection prevention program and argue that a critical assessment of safety practices is possible without significant grant funding. We reviewed 121 peer-reviewed manuscripts published by the VCU Hospital Infection Prevention Program over 16 years. Publications included quasi-experimental studies, observational studies, surveys, interrupted time series analyses, and editorials. We summarized the articles based on their infection prevention focus, and we provide a brief summary of the findings. We also summarized the involvement of nonfaculty learners in these manuscripts as well as the contributions of grant funding. Despite the absence of significant grant funding, infection prevention programs can critically assess safety strategies under the learning hospital framework by leveraging a diverse collaboration of motivated nonfaculty learners. This model is a valuable adjunct to traditional grant-funded efforts in infection prevention science and is part of a successful horizontal infection control program.

Synthesis and Antimicrobial Activity of Thiohydantoins Obtained from L-Amino Acids

Background:

Thiohydantoins are an important class of heterocyclic compounds in drug discovery since they are related to a wide range of biological properties including antimicrobial activity.

Objective:

The objective of this study was to synthesize a series of thiohydantoins derived from Laminoacids and to evaluated their inhibitory effect on the growth of Gram-negative and Grampositive bacteria.

Methods:

All title compounds were synthetized by reaction of L-amino acids with thiourea or ammonium thiocyanate. Their antimicrobial activities were evaluated against bacterial strains by broth microdilution assays. The time-kill kinetics, the antibiofilm activity and the cytotoxicity to mammalian cells were determined for the compound that exhibited the best antimicrobial profile (1b).

Results:

Eleven thiohydantoins were readily obtained in good yields (52-95%). In general, thiohydantoins were more effective against Gram-positive bacteria. Compound 1b (derived from Lalanine) showed the best antibacterial activity against Staphylococcus epidermis ATCC 12228 and S. aureus BEC 9393 with MIC values of 940 and 1921 µM, respectively. The time-kill kinetics demonstrated time-dependent bactericidal effect in both strains for this derivative. Besides, 1b also exhibited antibacterial activity against biofilms of S. epidermidis ATCC 12228, leading to a 40% reduction in their metabolic activity compared to the untreated control. No cytotoxicity of 1b to mammalian cells was observed at MIC values.

Conclusion:

The data reported herein indicate relevant antimicrobial activity of thiohydantoins derived from L-aminoacid, mainly 1b, as potential pharmacophore to guide further chemical modification aiming at the search for new and improved antimicrobial agents.

Health Care-Associated Infections and the Radiology Department

Health care-associated infections (HCAIs) are a significant concern for both health care workers (HCWs) and patients. They are a major contributing factor of disease in industrialized countries, and are responsible for significant morbidity, mortality, and a direct annual financial loss of $6-7 billion in North America alone. They are an increasingly challenging health issue due to multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci among others, along with an increasing number of susceptible patients. Over the last three decades, the risk of HCAIs has increased in the radiology department (RD) in part because of an increased number of patients visiting the department and an increase in the utilization of imaging modalities. In this review, we will discuss how patients and staff can be exposed to HCAIs in the RD, including contaminated inanimate surfaces, radiology equipment, and associated medical devices. As the role of medical imaging has extended from primarily diagnosis to include more interventions, the implementation and development of standardized infection minimization protocols and infection control procedures are vital in the RD, particularly in interventional radiology. With globalisation and the rapid movement of people regionally, nationally, and globally, there is greater risk of exposure to contagious diseases such as Ebola, especially if infected patients are undiagnosed when they travel. For effective infection control, advanced training and education of HCWs in the RD is essential. The purpose of this article is to provide an overview of HCAIs as related to activities of the RD. We will discuss the following major topics including the variety of HCAIs commonly encountered, the role of the RD in HCAIs, transmission of infections to patients and HCWs in the RD, standard infection prevention measures, and the management of susceptible/infected patients in the RD. We shall also examine the role of, and the preparedness of, HCWs, including RD technologists and interventional radiologists, who may be exposed to undiagnosed, yet infected patients. We shall conclude with a brief discussion of the role of further research related to HCAIs. Learning Objectives After the completion of this review article, the readers will • Understand the exposure and role of radiology department in health care-associated infections, • Know the causes/modes/transmission of infections in radiology department, • Be conscious of standard disinfection protocols, • Be aware of current and future strategies required for the effective control of health care-associated infection in the radiology department. This is a CME article and provides the equivalent of 2 hours of continuing education that may be applied to your professional development credit system. A 10-question multiple-choice quiz follows this reading. Please note that no formalized credit (category A) is available from CAMRT.

Low-cost antimicrobial fortification of ultrasound coupling gel: An ergonomic innovation to combat sonology-acquired nosocomial infections

Background

Recent outbreaks of highly contagious diseases have prompted hospital departments to adopt preventive hygiene protocols. Use of shared equipment, including ultrasound transducers and coupling gels, potentially exposes patients to these microbes. Inexpensive means of microbicide fortification of plain/non-sterile ultrasound gel may be useful in interrupting nosocomial infections. The purpose of this study was to evaluate the effectiveness of low-cost antimicrobial fortification of ultrasound coupling gel in preventing nosocomial infections during ultrasound examinations.

Methods

Volunteer patients, 20 in number, who presented for an ultrasound scan in a busy radiology clinic in Enugu, Nigeria, were randomly divided into 2 groups of 10 each and were scanned using plain non-sterile gel and gel-fortified with 0.5% chlorhexidine and 70% ethyl alcohol (in a volume ratio of 20:2:1) respectively. Swabs were taken from the patients' skin, gel-laden transducer, and the cleaned transducer and subjected to microbiology analysis. Subsequently, plain and fortified gel samples were allowed to stand in their respective dispensers for 72 hours. The plain and fortified gel samples were subjected to microbiology analysis. Fisher's Exact Test was utilised to compare outcomes in the 2 groups of volunteers.

Results

With fortified gel, swab cultures from patients' skin and gel-laden transducer, and from the cleaned transducer, significantly yielded no growth (P= <0.0001 and P= 0.0001 respectively) while swab cultures from the plain gel yielded a total of 19 microbial isolates from 5 micro-organisms.

Conclusion

Low-cost fortification of ultrasound coupling gel with 0.5% chlorhexidine and 70% ethyl alcohol renders it hostile to microorganisms encountered at sonology thus preventing nosocomial transmission.

Biofilm formation by staphylococci in health-related environments and recent reports on their control using natural compounds

Staphylococci are Gram-positive bacteria that are ubiquitous in the environment and able to form biofilms on a range of surfaces. They have been associated with a range of human health issues such as medical device-related infection, localized skin infection, or direct infection caused by toxin production. The extracellular material produced by these bacteria resists antibiotics and host defence mechanism which complicates the treatment process. The commonly reported Staphylococcus species are Staphylococcus aureus and S. epidermidis as they inhabit human bodies. However, the emergence of other staphylococci, such as S. haemolyticus, S. lugdunensis, S. saprophyticus, S. capitis, S. saccharolyticus, S. warneri, S. cohnii, and S. hominis, is also of concern and they have been associated with biofilm formation. This review critically assesses recent cases on the biofilm formation by S. aureus, S. epidermidis, and other staphylococci reported in health-related environments. The control of biofilm formation by staphylococci using natural compounds is specifically discussed as they represent potential anti-biofilm agents which may reduce the burden of antibiotic resistance.

Blood coagulation response and bacterial adhesion to biomimetic polyurethane biomaterials prepared with surface texturing and nitric oxide release

A dual functional polyurethane (PU) film that mimics aspects of blood vessel inner surfaces by combining surface texturing and nitric oxide (NO) release was fabricated through a soft lithography two-stage replication process. The fabrication of submicron textures on the polymer surface was followed by solvent impregnation with the NO donor, S-nitroso-N-acetylpenicillamine (SNAP). An in vitro plasma coagulation assay showed that the biomimetic surface significantly increased the plasma coagulation time and also exhibited reduced platelet adhesion and activation, thereby reducing the risk of blood coagulation and thrombosis. A contact activation assay for coagulation factor XII (FXII) demonstrated that both NO release and surface texturing also reduced FXII contact activation, which contributes to the inhibition of plasma coagulation. The biomimetic surface was also evaluated for bacterial adhesion in plasma and results demonstrate that this combined strategy enables a synergistic effect to reduce bacterial adhesion of Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa microorganisms. The results strongly suggest that the biomimetic modification with surface texturing and NO release provides an effective approach to improve the biocompatibility of polymeric materials in combating thrombosis and microbial infection. STATEMENT OF SIGNIFICANCE: (1) Developed a dual functional polyurethane (PU) film that mimics blood vessel inner surface by combining surface texturing and nitric oxide (NO) release for combatting biomaterial associated thrombosis and microbial infection. (2) Studied the blood coagulation response and bacterial adhesion to such biomimetic PU surfaces, and demonstrated that the combination of surface texturing and NO release synergistically reduced the platelet adhesion and bacterial adhesion in plasma, providing an effective approach to improve the biocompatibility of biomaterials used in blood-contacting medical devices. (3) The NO releasing surface significantly inhibits the plasma coagulation via the reduction of contact activation of FXII, indicating the multifunctional roles of NO in improving the biocompatibility of biomaterials in blood-contacting medical devices.

Biofilm inhibiting activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms

AIMS

To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.

METHODS AND RESULTS

The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by subfractionation to obtain betacyanin fraction. The anti-biofilm activity was examined using broth microdilution assay on polystyrene surfaces and expressed as minimum biofilm inhibitory concentration (MBIC). The betacyanin fraction from red spinach showed better anti-biofilm activity (MBIC: 0·313-1·25 mg ml^-1 ) against five Staph. aureus strains while the betacyanin fraction from red pitahaya showed better anti-biofilm activity (MBIC: 0·313-0·625 mg ml^-1 ) against four P. aeruginosa strains. Both betacyanin fraction significantly reduced hydrophobicity of Staph. aureus and P. aeruginosa strains. Numbers of Staph. aureus and P. aeruginosa attached to polystyrene were also reduced without affecting their cell viability.

CONCLUSION

Betacyanins can act as anti-biofilm agents against the initial step of biofilm formation, particularly on a hydrophobic surface like polystyrene.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study is the first to investigate the use of betacyanin as a biofilm inhibitory agent. Betacyanin could potentially be used to reduce the risk of biofilm-associated infections.

Antimicrobial resistance in bacterial pathogens among hospitalised patients with severe invasive infections

The most severe infections are invasive infections, due to the fact that the germs can accumulate in multiple sites and produce a body-wide infection known as sepsis. Septic shock has the highest mortality rate among non-traumatic medical conditions. In this study, we aimed to evaluate the incidence and prevalence of invasive infections in a hospital environment. Another second objective was to establish the aetiology of invasive infections in our hospital and the antibiotic resistance profile of the germs involved, which are both important for determining the therapeutic approach for the treatment of these infections. The study included 505 hospitalized patients from which we collected a total of 974 blood cultures. For the analysis of the blood cultures, we used an automated incubator. The bottles flagged as positive were subcultured on blood agar, and the grown colonies were identified using an identification system. Invasive infections had a prevalence rate of 27.72% in our hospital. From the 974 blood cultures, we isolated 170 bacterial strains: Staphylococcus aureus (SA; 63 strains, 37.06%), Klebsiella spp. (27 strains, 15.88%), coagulase-negative staphylococci (CoNS; 18 strains, 10.59%), Enterococcus spp. (17 strains, 10.00%), Escherichia coli (12 strains, 7.06%), Streptococcus spp. (11 strains, 6.47%) and other bacterial species. The prevalence of methicillin-resistant SA (MRSA) in our study was 36.51% from the SA strains. The MRSA prevalence differed significantly according to age (37.50% in adults vs. 28.57% in children, P=0.047) and ICU admission (42.42% in ICU patients vs. 30.00% in non-ICU patients, P=0.018). We performed a multivariate analysis of the invasive infection risk which detected as significant predictors the admission into the cardiology ward and plastic surgery ward. On the whole, the findings of this study indicate that the high prevalence of Gram-positive cocci in blood cultures, mostly SA, with multidrug resistance has important consequences for the management of invasive infections.

The continuous changes in the aetiology and epidemiology of invasive candidiasis: from familiar Candida albicans to multiresistant Candida auris

Recent changes in the aetiology and epidemiology of invasive candidiasis have serious implications for current and future diagnosis, treatment and prognosis. The aim of the current review was to discuss the epidemiology of invasive candidiasis, the distribution of Candida species in different regions of the world, the medical concerns of the changing aetiology and the emergence of antifungal resistance. Overall burden of invasive candidiasis remains high, especially in vulnerable persons, such as the elderly, immunosuppressed or debilitated patients. Moreover, there is a progressive shift in the aetiology of invasive candidiasis from Candida albicans to other species of Candida, probably related to the increased use of azole drugs with a clear trend towards increased antifungal resistance. Finally, the emergence and rise of multiresistant species, such as Candida auris or Candida glabrata, is a major threat making necessary invasive candidiasis worldwide surveillances. These changes have serious implications for the diagnosis, treatment and prognosis of invasive candidiasis. Updated knowledge of the current local epidemiology of invasive candidiasis is critical for the clinical management.

Relative Abundances of Candida albicans and Candida glabrata in In Vitro Coculture Biofilms Impact Biofilm Structure and Formation

Candida is a member of the normal human microbiota and often resides on mucosal surfaces such as the oral cavity or the gastrointestinal tract. In addition to their commensality, Candida species can opportunistically become pathogenic if the host microbiota is disrupted or if the host immune system becomes compromised. An important factor for Candida pathogenesis is its ability to form biofilm communities. The two most medically important species-Candida albicans and Candida glabrata-are often coisolated from infection sites, suggesting the importance of Candida coculture biofilms. In this work, we report that biofilm formation of the coculture population depends on the relative ratio of starting cell concentrations of C. albicans and C. glabrata When using a starting ratio of C. albicans to C. glabrata of 1:3, ∼6.5- and ∼2.5-fold increases in biofilm biomass were observed relative to those of a C. albicans monoculture and a C. albicans/C. glabrata ratio of 1:1, respectively. Confocal microscopy analysis revealed the heterogeneity and complex structures composed of long C. albicans hyphae and C. glabrata cell clusters in the coculture biofilms, and reverse transcription-quantitative PCR (qRT-PCR) studies showed increases in the relative expression of the HWP1 and ALS3 adhesion genes in the C. albicans/C. glabrata 1:3 biofilm compared to that in the C. albicans monoculture biofilm. Additionally, only the 1:3 C. albicans/C. glabrata biofilm demonstrated an increased resistance to the antifungal drug caspofungin. Overall, the results suggest that interspecific interactions between these two fungal pathogens increase biofilm formation and virulence-related gene expression in a coculture composition-dependent manner.IMPORTANCECandida albicans and Candida glabrata are often coisolated during infection, and the occurrence of coisolation increases with increasing inflammation, suggesting possible synergistic interactions between the two Candida species in pathogenesis. During the course of an infection, the prevalence of each Candida species may change over time due to differences in metabolism and in the resistance of each species to antifungal therapies. Therefore, it is necessary to understand the dynamics between C. albicans and C. glabrata in coculture to develop better therapeutic strategies against Candida infections. Existing in vitro work has focused on understanding how an equal-part culture of C. albicans and C. glabrata impacts biofilm formation and pathogenesis. What is not understood, and what is investigated in this work, is how the composition of Candida species in coculture impacts overall biofilm formation, virulence gene expression, and the therapeutic treatment of biofilms.

A computational model for regulation of nanoscale glucan exposure in Candida albicans

Candida albicans is a virulent human opportunistic pathogen. It evades innate immune surveillance by masking an immunogenic cell wall polysaccharide, β-glucan, from recognition by the immunoreceptor Dectin-1. Glucan unmasking by the antifungal drug caspofungin leads to changes in the nanostructure of glucan exposure accessible to Dectin-1. The physical mechanism that regulates glucan exposure is poorly understood, but it controls the nanobiology of fungal pathogen recognition. We created computational models to simulate hypothetical physical processes of unmasking glucan in a biologically realistic distribution of cell wall glucan fibrils. We tested the predicted glucan exposure nanostructural features arising from these models against experimentally measured values. A completely spatially random unmasking process, reflective of random environmental damage to the cell wall, cannot account for experimental observations of glucan unmasking. However, the introduction of partially edge biased unmasking processes, consistent with an unmasking contribution from active, local remodeling at glucan exposure sites, produces markedly more accurate predictions of experimentally observed glucan nanoexposures in untreated and caspofungin-treated yeast. These findings suggest a model of glucan unmasking wherein cell wall remodeling processes in the local nanoscale neighborhood of glucan exposure sites are an important contributor to the physical process of drug-induced glucan unmasking in C. albicans.

The bacterial contamination rate of glucose meter test strips in the hospital setting

Objectives:

To assess the rate of bacterial contamination of the multi-use vial and single-use packed glucose meter strips, and to identify the type and frequency of various bacterial contamination in different hospital wards.

Methods:

This prospective observational study was conducted by a team from the Strategic Center for Diabetes Research in 7 general hospitals in the Central region of Saudi Arabia during the period from August to September 2014 to assess the bacterial contamination rate of the unused strips. A total of 10,447 strips were cultured using proper agar media and incubated both aerobically and anaerobically.

Results:

The total bacterial contamination rate for the multi-use vials glucose strips was 31.7%, while single-use packed strips were not contaminated at all. Ministry of Health hospitals had the highest contamination rates compared with other hospitals. Critical, obstetric, and surgical wards had the highest bacterial isolates number, where most were in the risk group 3 according to the National Institute of Health guidelines. Staphylococcus species were the most common bacteria found.

Conclusion:

Glucose meter strips should be recognized as a source of bacterial contamination that could be behind serious hospital acquired infections. The hospital infection control team should adopt proper measures to implement protocols for glucose meter cleaning and glucose strips handling.

Nontoxic Cationic Coumarin Polyester Coatings Prevent Pseudomonas aeruginosa Biofilm Formation

The rapid increase in bacterial infections and antimicrobial resistance is a growing public health concern. Infections arising from bacterial contamination of surgical tools, medical implants, catheters, and hospital surfaces can potentially be addressed by antimicrobial polymeric coatings. The challenge in developing such polymers for in vivo use is the ability to achieve high antimicrobial efficacy while at the same time being nontoxic to human cells. Although several classes of antimicrobial polymers have been developed, many of them cannot be used in the clinical setting due to their nonselective toxicity toward bacteria and mammalian cells. Here, we demonstrate that coumarin polyesters with cationic pendant groups are very effective against Gram negative Pseudomonas aeruginosa. Coumarin polyesters with pendant cationic amine groups were coated onto glass coverslips and tested for their antimicrobial activity against P. aeruginosa colonization of the surface. The results demonstrate that the cationic coumarin polyester kills the surface attached bacterial cells preventing biofilm formation but does not show any hemolytic activity or discernible toxicity toward mammalian cells. The antimicrobial polyesters described in this work have several advantages desired in antimicrobial coatings such as high antimicrobial activity, low toxicity toward mammalian cells, visualization and ease of synthesis and fabrication, all of which are necessary for translation to the clinic.

Peripheral Venous Catheter-Related Adverse Events: Evaluation from a Multicentre Epidemiological Study in France (the CATHEVAL Project)

Introduction

Peripheral venous catheters (PVC) are medical devices most frequently used during hospital care. Although the frequency of specific PVC-related adverse events (PVCAEs) has been reported, the global risk related to the insertion of this device is poorly estimated. The aim of this study is to determine the incidence of PVCAEs during the indwell time, after catheter removal, and to identify practice-mirroring risk factors.

Methods

A prospective observational study was conducted as a part of a research project, called CATHEVAL, in one surgery ward and four medicine wards from three public general tertiary care hospitals in Northern France that were invited to participate between June-2013 and June-2014. Each participating ward included during a two-month study period all patients older than 15 years carrying a PVC. All inserted PVCs were monitored from insertion of PVC to up to 48 hours after removal. Monitored data included several practice-mirroring items, as well as the occurrence of at least one PVCAE. A multivariate Cox proportional hazard model, based on a marginal risk approach, was used to identify factors associated with the occurrence of at least one PVCAE.

Results

Data were analysed for 815 PVCs (1964 PVC-days) in 573 patients. The incidence of PVCAE was 52.3/100 PVCs (21.9/100 PVC-days). PVCAEs were mainly clinical: phlebitis (20.1/100 PVCs), haematoma (17.7/100 PVCs) and liquid/blood escape (13.1/100 PVCs). Infections accounted for only 0.4/100 PVCs. The most frequent mechanical PVCAEs, was obstruction/occlusion of PVC (12.4/100 PVCs). The incidence of post-removal PVCAEs was 21.7/100 PVCs. Unstable PVC and unclean dressing were the two main risk factors.

Conclusion

Limitation of breaches in healthcare quality including post-removal monitoring should be reinforced to prevent PVC-related adverse events in hospital settings.

Hyperspectral fluorescence microscopy detects autofluorescent factors that can be exploited as a diagnostic method for Candida species differentiation

Fungi in the Candida genus are the most common fungal pathogens. They not only cause high morbidity and mortality but can also cost billions of dollars in healthcare. To alleviate this burden, early and accurate identification of Candida species is necessary. However, standard identification procedures can take days and have a large false negative error. The method described in this study takes advantage of hyperspectral confocal fluorescence microscopy, which enables the capability to quickly and accurately identify and characterize the unique autofluorescence spectra from different Candida species with up to 84% accuracy when grown in conditions that closely mimic physiological conditions.

Outcome of bloodstream infections among spinal cord injury patients and impact of multidrug-resistant organisms

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Our study aimed to describe the outcome of bloodstream infection (BSI) in spinal cord injury (SCI) patients and their associated risk factors for severity and mortality.

SETTING

A French University Hospital.

METHODS

We conducted a retrospective cohort study of all BSIs occurring in hospitalized SCI patients. We analyzed their outcome and risk factors especially the impact of multidrug-resistant organisms (MDROs).

RESULTS

Overall, 318 BSIs occurring among 256 patients were included in the analysis. Mean age was 50.8 years and gender ratio (M/F) was 2.70, with a mean injury duration of 11.6 years.Severity and 30-day mortality of BSI episodes were, respectively, 43.4% and 7.9%. BSI severity was significantly more frequent when caused by respiratory tract infections (RTIs) (odds ratio (OR)=1.38; 95% confidence interval (CI): 1.13-1.44) and significantly lower when caused by urinary tract infections (UTIs) (OR=0.47; 95% CI: 0.28-0.76). BSI mortality was significantly higher when caused by RTIs (OR=3.08; 95% CI: 1.05-8.99), catheter-related bloodstream infections (OR=3.54; 95% CI: 1.36-9.18) or Pseudomonas aeruginosa infections (OR=3.79; 95% CI: 1.14-12.55).MDROs were responsible for 41.2% of all BSI. They have no impact on severity and mortality, whichever be the primary site of infection.In multivariate analysis, mortality was higher when BSI episodes were due to RTIs (OR=3.26; 95% CI: 1.29-8.22) and Pseudomonas aeruginosa infections (OR=3.53; 95% CI: 1.06-11.70), or when associated with immunosuppressive therapy (OR=2.57; 95% CI: 1.14-5.78) or initial severity signs (OR=1.68; 95% CI: 1.01-2.81).

CONCLUSION

BSI occurring in SCI population were often severe but mortality remained low. MDROs were frequent but not associated with severity or mortality of BSI episodes. Risk factors associated with mortality were initial severe presentation, RTI, immunosuppressive therapy and BSI due to Pseudomonas aeruginosa.

Characterising health care-associated bloodstream infections in public hospitals in Queensland, 2008-2012

OBJECTIVE

To describe the epidemiology and rates of all health care-associated bloodstream infections (HA-BSIs) and of specific HA-BSI subsets in public hospitals in Queensland.

DESIGN AND SETTING

Standardised HA-BSI surveillance data were collected in 23 Queensland public hospitals, 2008-2012.

MAIN OUTCOME MEASURES

HA-BSIs were prospectively classified in terms of place of acquisition (inpatient, non-inpatient); focus of infection (intravascular catheter-associated, organ site focus, neutropenic sepsis, or unknown focus); and causative organisms. Inpatient HA-BSI rates (per 10,000 patient-days) were calculated.

RESULTS

There were 8092 HA-BSIs and 9418 causative organisms reported. Inpatient HA-BSIs accounted for 79% of all cases. The focus of infection in 2792 cases (35%) was an organ site, intravascular catheters in 2755 (34%; including 2240 central line catheters), neutropenic sepsis in 1063 (13%), and unknown in 1482 (18%). Five per cent (117 of 2240) of central line-associated BSIs (CLABSIs) were attributable to intensive care units (ICUs). Eight groups of organisms provided 79% of causative agents: coagulase-negative staphylococci (18%), Staphylococcus aureus (15%), Escherichia coli (11%), Pseudomonas species (9%), Klebsiella pneumoniae/oxytoca (8%), Enterococcus species (7%), Enterobacter species (6%), and Candida species (5%). The overall inpatient HA-BSI rate was 6.0 per 10,000 patient-days. The rates for important BSI subsets included: intravascular catheter-associated BSIs, 1.9 per 10,000 patient-days; S. aureus BSIs, 1.0 per 10,000 patient-days; and methicillin-resistant S. aureus BSIs, 0.3 per 10,000 patient-days.

CONCLUSIONS

The rate of HA-BSIs in Queensland public hospitals is lower than reported by similar studies elsewhere. About one-third of HA-BSIs are attributable to intravascular catheters, predominantly central venous lines, but the vast majority of CLABSIs are contracted outside ICUs. Different sources of HA-BSIs require different prevention strategies.

Tissue engineering of nanosilver-embedded peripheral nerve scaffold to repair nerve defects under contamination conditions

INTRODUCTION

We employed a nanosilver-collagen scaffold and tested its effects on inhibiting bacteria and facilitating nerve regeneration.

METHODS

Based on our previous research, we prepared bionic scaffolds with different concentrations of nanosilver and examined their internal structures by scanning electron microscopy and energy dispersive spectroscopy. We implanted these scaffolds or autologous nerve grafts into rats to repair a 10-mm injury of the sciatic nerve.

RESULTS

The 2 mg/ml group showed a >10 mm bacterial inhibition zone in all 3 types of bacterial culture dishes. At day 60 postsurgery, the 2 mg/ml group also showed the highest amplitude of evoked potential (AMP) and nerve conduction velocity (NCV). The regenerating nerves in the 2 mg/ml group were denser and more mature, and with thicker and well-arrayed myelin sheath.

CONCLUSIONS

These results demonstrate that nanosilver scaffolds (2 mg/ml group) were effective in inhibiting bacteria both in vitro and in vivo, and reduced the contamination-caused immune responses, which in turn promoted nerve regeneration and functional recovery.

Blood stream infections due to multidrug-resistant organisms among spinal cord-injured patients, epidemiology over 16 years and associated risks: a comparative study

STUDY DESIGN

Retrospective study.

OBJECTIVES

We aimed to describe the epidemiology of multidrug-resistant organisms (MDROs) during bloodstream infection (BSI) and identify associated risks of MDROs among patients with spinal cord injury (SCI).

SETTING

A teaching hospital, expert center in disability, in France.

METHODS

We studied a retrospective cohort of all BSIs occurring in SCI patients hospitalized over 16 years. We described the prevalence of MDRO BSI among this population and its evolution over time and compared the BSI population due to MDROs and due to non-MDROs.

RESULTS

A total of 318 BSIs occurring among 256 patients were included in the analysis. The most frequent primary sites of infection were urinary tract infection (34.0%), pressure sore (25.2%) and catheter line-associated bloodstream infection (11.3%). MDROs were responsible for 41.8% of BSIs, and this prevalence was stable over 16 years. No significant associated factor for MDRO BSI could be identified concerning sociodemographic and clinical characteristics, primary site of infection and bacterial species in univariate and multivariate analyses. BSI involving MDROs was not associated with initial severity of sepsis compared with infection without MDROs (43.8 vs 43.6%, respectively) and was not associated either with 30th-day mortality (6.2 vs 9%, respectively).

CONCLUSION

During BSI occurrence in an SCI population, MDROs are frequent but remain stable over years. No associated risk can be identified that would help optimize antibiotic treatment. Neither the severity of the episode nor the mortality is significantly different when an MDRO is involved.

A bioassay-guided fractionation scheme for characterization of new antibacterial compounds from Prosopis cineraria aerial parts

BACKGROUND AND OBJECTIVES

Due to the importance of finding of new antibacterial agents, the antibacterial properties of Prosopis cineraria aerial parts were investigated using a bioassay guided fractionation scheme.

MATERIALS AND METHODS

The organic extract was prepared via maceration in methanol, followed by the fractionation using n-hexane and ethyl acetate. The MICs of fractions were determined against some human pathogenic bacteria using broth micro-dilution assay. The primary characterization and identification of bioactive substance(s) was based on a bio-autographical method using HPTLC and flash chromatography in parallel with agar overlay assays. Finally the exact mass of effective compound(s) was determined by LC-MS.

RESULTS

The best antibacterial activities were related to the ethyl acetate fraction. The effective antibacterial compound of the plant were 2 substances with molecular weight of 348 and 184 Dalton that inhibited the growth of assessed Gram positive bacteria with MIC values lower than 125 to 62.5 μg/ml synergistically.

CONCLUSION

Further analysis using nuclear magnetic resonance could reveal the exact structure of these two antibacterial substances. These 2 effective antibacterial compounds could be applied as lead compound for synthesis of new antibacterial agents.

Silver-nanoparticle-coated biliary stent inhibits bacterial adhesion in bacterial cholangitis in swine

BACKGROUND

One of the major limitations of biliary stents is the stent occlusion, which is closely related to the over-growth of bacteria. This study aimed to evaluate the feasibility of a novel silver-nanoparticle-coated polyurethane (Ag/PU) stent in bacterial cholangitis model in swine.

METHODS

Ag/PU was designed by coating silver nanoparticles on polyurethane (PU) stent. Twenty-four healthy pigs with bacterial cholangitis using Ag/PU and PU stents were randomly divided into an Ag/PU stent group (n=12) and a PU stent group (n=12), respectively. The stents were inserted by standard endoscopic retrograde cholangiopancreatography. Laboratory assay was performed for white blood cell (WBC) count, alanine aminotransferase (ALT), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) at baseline time, 8 hours, 1, 2, 3, and 7 days after stent placements. The segment of bile duct containing the stent was examined histologically ex vivo. Implanted biliary stents were examined by a scan electron microscope. The amount of silver release was also measured in vitro.

RESULTS

The number of inflammatory cells and level of ALT, IL-1beta and TNF-alpha were significantly lower in the Ag/PU stent group than in the PU stent group. Hyperplasia of the mucosa was more severe in the PU stent group than in the Ag/PU stent group. In contrast to the biofilm of bacteria on the PU stent, fewer bacteria adhered to the Ag/PU stent.

CONCLUSIONS

PU biliary stents modified with silver nanoparticles are able to alleviate the inflammation of pigs with bacterial cholangitis. Silver-nanoparticle-coated stents are resistant to bacterial adhesion.

Nanoscopic cell-wall architecture of an immunogenic ligand in Candida albicans during antifungal drug treatment

Candida albicans evades immunity by limiting cell-wall β-glucan exposure. dSTORM imaging reveals that “unmasking”of glucan by an antifungal drug occurs through nanoscale reorganization of glucan exposure geometry. Nanostructuring of glucan might play a role in innate immune activation and provides insights into the physical regulation of glucan exposure.

The cell wall of Candida albicans is composed largely of polysaccharides. Here we focus on β-glucan, an immunogenic cell-wall polysaccharide whose surface exposure is often restricted, or “masked,” from immune recognition by Dectin-1 on dendritic cells (DCs) and other innate immune cells. Previous research suggested that the physical presentation geometry of β-glucan might determine whether it can be recognized by Dectin-1. We used direct stochastic optical reconstruction microscopy to explore the fine structure of β-glucan exposed on C. albicans cell walls before and after treatment with the antimycotic drug caspofungin, which alters glucan exposure. Most surface-accessible glucan on C. albicans yeast and hyphae is limited to isolated Dectin-1–binding sites. Caspofungin-induced unmasking caused approximately fourfold to sevenfold increase in total glucan exposure, accompanied by increased phagocytosis efficiency of DCs for unmasked yeasts. Nanoscopic imaging of caspofungin-unmasked C. albicans cell walls revealed that the increase in glucan exposure is due to increased density of glucan exposures and increased multiglucan exposure sizes. These findings reveal that glucan exhibits significant nanostructure, which is a previously unknown physical component of the host–Candida interaction that might change during antifungal chemotherapy and affect innate immune activation.

T cells from patients with Candida sepsis display a suppressive immunophenotype

BACKGROUND

Despite appropriate therapy, Candida bloodstream infections are associated with a mortality rate of approximately 40%. In animal models, impaired immunity due to T cell exhaustion has been implicated in fungal sepsis mortality. The purpose of this study was to determine potential mechanisms of fungal-induced immunosuppression via immunophenotyping of circulating T lymphocytes from patients with microbiologically documented Candida bloodstream infections.

METHODS

Patients with blood cultures positive for any Candida species were studied. Non-septic critically ill patients with no evidence of bacterial or fungal infection were controls. T cells were analyzed via flow cytometry for cellular activation and for expression of positive and negative co-stimulatory molecules. Both the percentages of cells expressing particular immunophenotypic markers as well as the geometric mean fluorescence intensity (GMFI), a measure of expression of the number of receptors or ligands per cell, were quantitated.

RESULTS

Twenty-seven patients with Candida bloodstream infections and 16 control patients were studied. Compared to control patients, CD8 T cells from patients with Candidemia had evidence of cellular activation as indicated by increased CD69 expression while CD4 T cells had decreased expression of the major positive co-stimulatory molecule CD28. CD4 and CD8 T cells from patients with Candidemia expressed markers typical of T cell exhaustion as indicated by either increased percentages of or increased MFI for programmed cell death 1 (PD-1) or its ligand (PD-L1).

CONCLUSIONS

Circulating immune effector cells from patients with Candidemia display an immunophenotype consistent with immunosuppression as evidenced by T cell exhaustion and concomitant downregulation of positive co-stimulatory molecules. These findings may help explain why patients with fungal sepsis have a high mortality despite appropriate antifungal therapy. Development of immunoadjuvants that reverse T cell exhaustion and boost host immunity may offer one way to improve outcome in this highly lethal disorder.

Interfacial Self-Assembly of Heparin-Mimetic Multilayer on Membrane Substrate as Effective Antithrombotic, Endothelialization, and Antibacterial Coating

In this study, we design the interfacial self-assembly of heparin-mimetic multilayer on poly(ether sulfone) (PES) membrane, which can endow the substrate with excellent cytocompatibility, highly hemocompatibility and enhanced antibacterial properties. The coated 3D sponge-like multilayer was fabricated by surface engineered layer by layer assembly of sulfonic amino polyether sulfone (SNPES) and quaternized chitosan (QC). The cell morphology observation and viability evaluation suggested that the assembled multilayer coating had remarkable cytocompatibility with endothelial cells due to the synergistic promotion of bovine serum albumin adsorption and heparin-mimetic groups; which further indicated that surface endothelialization could be achieved on the heparin-mimetic multilayer. The systematical tests of antithrombotic and blood activation indicated that the heparin-mimetic multilayer-coated membrane owned significantly suppressed adsorption of bovine serum fibrinogen, platelet adhesion and activation, prolonged clotting times, as well as lower activation of blood complement. Furthermore, the antibacterial test suggested the multilayer coated substrates exhibited obvious inhibition capability for both Escherichia coli and Staphylococcus aureus. Therefore, we believe that the developed SNPES/QC multilayer on PES membrane show great potential as a multifunctional coating toward versatile biomedical applications due to the integrated and highly effective antithrombotic, endothelialization, and antibacterial properties.

Hospital outpatient clinics as a potential hazard for healthcare associated infections

Healthcare acquired infections are no longer confined to the hospital environment. Recently, many reported outbreaks have been linked to outpatient settings and attributed to non-adherence to recommended infection-prevention procedures. This study was divided into two parts: The first is a descriptive cross-sectional part, to assess the healthcare personnel's knowledge and compliance with Standard Precautions (SP). The second is an intervention part to assess the role of health education on reducing the level of environmental and reusable medical equipment bacterial contamination. Assessment of the doctors' and nurses' knowledge and compliance with SP was performed using a self-administered questionnaire. Assessment of environmental cleaning (EC) and reusable medical equipment disinfection has been performed using aseptic swabbing method. The extent of any growth was recorded according to the suggested standards: (A) Presence of indicator organisms, with the proposed standard being <1cfu/cm(2). These include Staphylococcus aureus (including methicillin-resistant Staphylococcus aureus, MRSA), Enterococci, including vancomycin-resistant Enterococci (VRE) and various multidrug-resistant Gram-negative bacilli. (B) Aerobic colony count, the suggested standard is <5cfu/cm(2). The effect of health education intervention on cleaning and disinfection had been analyzed by comparing the difference in cleaning level before and after interventional education. Good knowledge and compliance scores were found in more than 50% of participants. Primary screening found poor EC and equipment disinfection as 67% and 83.3% of stethoscopes and ultrasound transducers, respectively, were contaminated with indicator organisms. For all indicator organisms, a significant reduction was detected after intervention (p=0.00). Prevalence of MRSA was 38.9% and 16.7%, of the total S. aureus isolates, before and after intervention, respectively. Although 27.8% of the total Enterococcus isolates were VRE before intervention, no VRE isolates were detected after intervention. These differences were significant. Development and monitoring of the implementation of infection prevention policies and training of HCP is recommended.

Cost-Effectiveness Analysis of a Transparent Antimicrobial Dressing for Managing Central Venous and Arterial Catheters in Intensive Care Units

OBJECTIVE

To model the cost-effectiveness impact of routine use of an antimicrobial chlorhexidine gluconate-containing securement dressing compared to non-antimicrobial transparent dressings for the protection of central vascular lines in intensive care unit patients.

DESIGN

This study uses a novel health economic model to estimate the cost-effectiveness of using the chlorhexidine gluconate dressing versus transparent dressings in a French intensive care unit scenario. The 30-day time non-homogeneous markovian model comprises eight health states. The probabilities of events derive from a multicentre (12 French intensive care units) randomized controlled trial. 1,000 Monte Carlo simulations of 1,000 patients per dressing strategy are used for probabilistic sensitivity analysis and 95% confidence intervals calculations. The outcome is the number of catheter-related bloodstream infections avoided. Costs of intensive care unit stay are based on a recent French multicentre study and the cost-effectiveness criterion is the cost per catheter-related bloodstream infections avoided. The incremental net monetary benefit per patient is also estimated.

PATIENTS

1000 patients per group simulated based on the source randomized controlled trial involving 1,879 adults expected to require intravascular catheterization for 48 hours.

INTERVENTION

Chlorhexidine Gluconate-containing securement dressing compared to non-antimicrobial transparent dressings.

RESULTS

The chlorhexidine gluconate dressing prevents 11.8 infections /1,000 patients (95% confidence interval: [3.85; 19.64]) with a number needed to treat of 85 patients. The mean cost difference per patient of €141 is not statistically significant (95% confidence interval: [€-975; €1,258]). The incremental cost-effectiveness ratio is of €12,046 per catheter-related bloodstream infection prevented, and the incremental net monetary benefit per patient is of €344.88.

CONCLUSIONS

According to the base case scenario, the chlorhexidine gluconate dressing is more cost-effective than the reference dressing.

TRIAL REGISTRATION

This model is based on the data from the RCT registered with www.clinicaltrials.gov (NCT01189682).

Eliminating Infections in the ICU: CLABSI

Central line-associated bloodstream infections (CLABSI) are one of the leading causes of death in the USA and around the world. As a preventable healthcare-associated infection, they are associated with significant morbidity and excess costs to the healthcare system. Effective and long-term CLABSI prevention requires a multifaceted approach, involving evidence-based best practices coupled with effective implementation strategies. Currently recommended practices are supported by evidence and are simple, such as appropriate hand hygiene, use of full barrier precautions, avoidance of femoral lines, skin antisepsis, and removal of unnecessary lines. The most successful and sustained improvements in CLABSI rates further utilize an adaptive component to align provider behaviors with consistent and reliable use of evidence-based practices. Great success has been achieved in reducing CLABSI rates in the USA and elsewhere over the past decade, but more is needed. This article aims to review the initiatives undertaken to reduce CLABSI and summarizes the sentinel and recent literature regarding CLABSI and its prevention.