Vancomycin-resistant Enterococci Research Articles

The real-world impact of the BioFire FilmArray blood culture identification 2 panel on antimicrobial stewardship among patients with bloodstream infections in intensive care units with a high burden of drug-resistant pathogens

BackgroundThe increasing prevalence of drug-resistant pathogens leads to delays in adequate antimicrobial treatment in intensive care units (ICU). The real-world influence of the BioFire FilmArray Blood Culture Identification 2 (BCID2) panel on pathogen identification, diagnostic concordance with conventional culture methods, and antimicrobial stewardship in the ICU remains unexplored. MethodsThis retrospective observational study, conducted from July 2021 to August 2023, involved adult ICU patients with positive blood cultures who underwent BCID2 testing. The concordance between BCID2 and conventional culture results was examined, and its impact on antimicrobial stewardship was assessed through a comprehensive retrospective review of patient records by intensivists. ResultsA total of 129 blood specimens from 113 patients were analysed. Among these patients, a high proportion of drug-resistant strains were noted, including carbapenem-resistant Klebsiella pneumoniae (CRKP) (57.1%), carbapenem-resistant Acinetobacter calcoaceticus-baumannii complex (100%), methicillin-resistant Staphylococcus aureus (MRSA) (70%), and vancomycin-resistant Enterococcus faecium (VRE) (100%). The time from blood culture collection to obtaining BCID2 results was significantly shorter than conventional culture (46.2 h vs. 86.9 h, p < 0.001). BCID2 demonstrated 100% concordance in genotype–phenotype correlation in antimicrobial resistance (AMR) for CRKP, carbapenem-resistant Escherichia coli, MRSA, and VRE. A total of 40.5% of patients received inadequate empirical antimicrobial treatment. The antimicrobial regimen was adjusted or confirmed in 55.4% of patients following the BCID2 results. ConclusionsIn the context of a high burden of drug-resistant pathogens, BCID2 demonstrated rapid pathogen and AMR detection, with a noticeable impact on antimicrobial stewardship in BSI in the ICU.

Vancomycin Resistant Enterococcus in Infected Walled Off Necrosis: Possible Causation &amp; Management

Peri-pancreatic fluid collections are frequently encountered by clinicians caring for patients who recover from acute or chronic pancreatitis. Although these fluid collections are common, the type of collection and resulting complications can significantly affect patient mortality. We present a 29-year-old female who originally presented with acetaminophen toxicity secondary to pain management for interstitial edematous pancreatitis (IEP) complicated by renal failure. The patient later developed intermittent fevers with concern for an underlying infection and was ultimately found to have walled-off necrosis (WON) infected by an uncommon hepaPeri-pancreatic fluid collections are frequently encountered by clinicians caring for patients who recover from acute or chronic pancreatitis. Although these fluid collections are common, the type of collection and resulting complications can significantly affect patient mortality. We present a 29-year-old female who originally presented with acetaminophen toxicity secondary to pain management for interstitial edematous pancreatitis (IEP) complicated by renal failure. The patient later developed intermittent fevers with concern for an underlying infection and was ultimately found to have walled-off necrosis (WON) infected by an uncommon hepatobiliary pathogen previously isolated in a urine culture despite asymptomatic bacteriuria. Background: Acute pancreatitis (AP) is divided into two categories: IEP and necrotizing pancreatitis (NP). Fluid collections are a common sequala for both subtypes. In IEP, fluid collections include acute peripancreatic fluid collections (APFCs) and pseudocysts (PC). Fluid collections in NP include acute necrotic collections (ANCs) and walled-off necrosis (WON) (1). All associated AP fluid collections carry an increased risk for infection, but speed and degree of management varies depending on the collection type (2). Objective: To report a case of AP complicated by a miscategorized fluid collection later determined to be WON with superimposed vancomycin resistant enterococcus (VRE) and discuss a unique approach to anti-microbial therapy selection. Atobiliary pathogen previously isolated in a urine culture despite asymptomatic bacteriuria.

Horizontal versus vertical strategies for infection prevention: current practices and controversies.

Healthcare-associated infections (HAIs) represent a major burden on healthcare facilities. Effective infection prevention strategies are essential to prevent the spread of HAIs. These can be broadly classified as vertical and horizontal interventions. Through this review, we aim to assess the merits of these strategies. Vertical strategies include active surveillance testing and isolation for patients infected or colonized with a particular organism. These strategies are beneficial to curb the spread of emerging pathogens and during outbreaks. However, the routine use of contact precautions for organisms such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus remains controversial. Horizontal interventions are larger-scale and reduce HAIs by targeting a common mode of transmission shared by multiple organisms. Among these, hand hygiene, chlorhexidine gluconate bathing of select patients and environmental decontamination are the most high-yield and must be incorporated into infection prevention programs. As antimicrobial stewardship is also an effective horizontal strategy, antimicrobial stewardship programs must operate in synergy with infection prevention programs for maximal impact. Overall, horizontal interventions are considered more cost-effective and have a broader impact. Infection control programs may opt for a combination of vertical and horizontal strategies based on local epidemiology and available resources.

A Case of Vancomycin-Resistant Enterococci Infection Treated with Korean Medicine

Hospital-acquired bacterial infections, including vancomycin-resistant enterococci (VRE) infection (MIC: 32 mcg/ml), are common. We describe the case of a 63-year-old female patient with subarachnoid hemorrhage and VRE infection treated with Jashin-bowon-tang and Samhuang-sashim-tang for 57 days and 22 days, respectively. The therapeutic effect was assessed weekly via culture, color and viscosity of pus from a coccyx sore, and C-reactive protein (CRP). Vital signs were checked four times a day. Seventeen days after treatment, VRE was not colonized in patient and color and viscosity of pus, CRP and vital sign were improved. This case report suggests that Jashin-bowon-tang and Samhuang-sashim-tang might be an alternative option for VRE infection patients reducing the need for extended isolation periods and speeding up recovery times.

Hospital Acquired Sepsis, Disease Prevalence, and Recent Advances in Sepsis Mitigation.

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, commonly associated with nosocomial transmission. Gram-negative bacterial species are particularly problematic due to the release of the lipopolysaccharide toxins upon cell death. The lipopolysaccharide toxin of E. coli has a greater immunogenic potential than that of other Gram-negative bacteria. The resultant dysregulation of the immune system is associated with organ failure and mortality, with pregnant women, ICU patients, and neonates being particularly vulnerable. Additionally, sepsis recovery patients have an increased risk of re-hospitalisation, chronic illness, co-morbidities, organ damage/failure, and a reduced life expectancy. The emergence and increasing prevalence of antimicrobial resistance in bacterial and fungal species has impacted the treatment of sepsis patients, leading to increasing mortality rates. Multidrug resistant pathogens including vancomycin-resistant Enterococcus, beta lactam-resistant Klebsiella, and carbapenem-resistant Acinetobacter species are associated with an increased risk of mortality. To improve the prognosis of sepsis patients, predominantly high-risk neonates, advances must be made in the early diagnosis, triage, and control of sepsis. The identification of suitable biomarkers and biomarker combinations, coupled with machine learning and artificial intelligence, show promise in early detection protocols. Rapid diagnosis of sepsis in patients is essential to inform on clinical treatment, especially with resistant infectious agents. This timely review aims to discuss sepsis prevalence, aetiology, and recent advances towards disease mitigation and control.

Studying the viability and growth kinetics of vancomycin-resistant Enterococcus faecalis V583 following femtosecond laser irradiation (420–465 nm)

Enterococcus faecalis is among the most resistant bacteria found in infected root canals. The demand for cutting-edge disinfection methods has rekindled research on photoinactivation with visible light. This study investigated the bactericidal activity of femtosecond laser irradiation against vancomycin-resistant Enterococcus faecalis V583 (VRE). The effect of parameters such as wavelength and energy density on the viability and growth kinetics of VRE was studied to design an optimized laser-based antimicrobial photoinactivation approach without any prior addition of exogenous photosensitizers. The most effective wavelengths were 430 nm and 435 nm at a fluence of 1000 J/cm2, causing a nearly 2-log reduction (98.6% and 98.3% inhibition, respectively) in viable bacterial counts. The colony-forming units and growth rate of the laser-treated cultures were progressively decreased as energy density or light dose increased at 445 nm but reached a limit at 1250 J/cm2. At a higher fluence of 2000 J/cm2, the efficacy was reduced due to a photobleaching phenomenon. Our results highlight the importance of optimizing laser exposure parameters, such as wavelength and fluence, in bacterial photoinactivation experiments. To our knowledge, this is the first study to report an optimized wavelength for the inactivation of VRE using visible femtosecond laser light.

Emergence and ongoing outbreak of ST80 vancomycin-resistant Enterococcus faecium in Guangdong province, China from 2021 to 2023: a multicenter, time-series and genomic epidemiological study

ABSTRACT Background: Surveillance systems revealed that the prevalence of vancomycin-resistant Enterococcus faecium (VREfm) has increased. We aim to investigate the epidemiological and genomic characteristics of VREfm in China. Methods: We collected 20,747 non-redundant E. faecium isolates from inpatients across 19 hospitals in six provinces between January 2018 and June 2023. VREfm was confirmed by antimicrobial susceptibility testing. The prevalence was analyzed using changepoint package in R. Genomic characteristics were explored by whole-genome sequencing. Results: 5.59% (1159/20,747) of E. faecium isolates were resistant to vancomycin. The prevalence of VREfm increased in Guangdong province from 5% before 2021 to 20−50% in 2023 (p < 0.0001), but not in the other five provinces. Two predominant clones before 2021, ST17 and ST78, were substituted by an emerging clone, ST80, from 2021 to 2023 (88.63%, 195/220). All ST80 VREfm from Guangdong formed a single lineage (SC11) and were genetically distant from the ST80 VREfm from other countries, suggesting a regional outbreak. All ST80 VREfm in SC11 carried a new type of plasmid harbouring a vanA cassette, which was embedded in a Tn1546-like structure flanked by IS1678 and ISL3. However, no conjugation-related gene was detected and no transconjugant was obtained in conjugation experiment, indicating that the outbreak of ST80 VREfm could be attributed to clonal transmission. Conclusions: We revealed an ongoing outbreak of ST80 VREfm with a new vanA-harbouring plasmid in Guangdong, China. This clone has also been identified in other provinces and countries, foreboding a risk of wider spreading shortly. Continuous surveillance is needed to inform public health interventions.

Bioactivity-Based Molecular Networking-Guided Isolation of Epicolidines A-C from the Endophytic Fungus Epicoccum sp. 1-042.

Bioactivity-based molecular networking-guided fractionation enabled the isolation of three new polycyclic tetramic acids bearing cis-decalin, epicolidines A-C (1-3), along with one known compound, PF 1052 (4), from the endophytic fungus Epicoccum sp. 1-042 collected in Tibet, China. Their structures were assigned on the basis of extensive spectroscopic data, partial hydrolysis, advanced Marfey's method, quantum chemistry calculations, and X-ray diffraction analysis. Compounds 2-4 displayed promising activities against Gram-positive bacteria in vitro. Particularly, compound 4 displayed remarkable potential against vancomycin-resistant Enterococcus faecium (VRE) with an MIC value of 0.25 μg/mL, lower than the MIC (0.5 μg/mL) of the antibiotic combination quinupristin/dalfopristin (Q/D). In a further in vivo study, compound 4 increased the survival rate to 100% in the VRE-G. mellonella infection model at a concentration of 10 mg/kg.

Evaluation of Antimicrobial Resistancein Clinical Isolates of Enterococcus spp. Obtained from Hospital Patients in Latvia.

Background and Objective: Enterococci are typically found in a healthy human gastrointestinal tract but can cause severe infections in immunocompromised patients. Such infections are treated with antibiotics. This study addresses the rising concern of antimicrobial resistance (AMR) in Enterococci, focusing on the prevalence of vancomycin-resistant enterococcus (VRE) strains. Materials and Methods: The pilot study involved 140 Enterococci isolates collected between 2021 and 2022 from two multidisciplinary hospitals (with and without local therapeutic drug monitoring protocol of vancomycin) in Latvia. Microbiological assays and whole genome sequencing were used. AMR gene prevalence with resistance profiles were determined and the genetic relationship and outbreak evaluation were made by applying core genome multi-locus sequence typing (cgMLST). Results: The acquired genes and mutations were responsible for resistance against 10 antimicrobial classes, including 25.0% of isolates expressing resistance to vancomycin, predominantly of the vanB type. Genetic diversity among E. faecalis and E. faecium isolates was observed and seven potential outbreak clusters were identified, three of them containing sequence types ST6, ST78 and ST80. The prevalence of vancomycin resistance was highest in the hospital without a therapeutic drug-monitoring protocol and in E. faecium. Notably, a case of linezolid resistance due to a mutation was documented. Conclusions: The study illustrates the concerning prevalence of multidrug-resistant Enterococci in Latvian hospitals, showcasing the rather widespread occurrence of vancomycin-resistant strains. This highlights the urgency of implementing efficient infection control mechanisms and the need for continuous VRE surveillance in Latvia to define the scope and pattern of the problem, influencing clinical decision making and planning further preventative measures.

Development of Penicillin-Based Carbonic Anhydrase Inhibitors Targeting Multidrug-Resistant Neisseria gonorrhoeae.

The development of antibacterial drugs with new mechanisms of action is crucial in combating the rise of antibiotic-resistant infections. Bacterial carbonic anhydrases (CAs, EC 4.2.1.1) have been validated as promising antibacterial targets against pathogens such as Helicobacter pylori, Neisseria gonorrhoeae, and vancomycin-resistant enterococci. A multitarget strategy is proposed to design penicillin-based CA inhibitor hybrids for tackling resistance by targeting multiple bacterial pathways, thereby resensitizing drug-resistant strains to clinical antibiotics. The sulfonamide derivatives potently inhibited the CAs from N. gonorrhoeae and Escherichia coli with KI values in the range of 7.1-617.2 nM. Computational simulations with the main penicillin-binding protein (PBP) of N. gonorrhoeae indicated that these hybrid derivatives maintained the mechanism of action of the lead β-lactams. A subset of derivatives showed potent PBP-related antigonococcal effects against multidrug-resistant N. gonorrhoeae strains, with several compounds significantly outperforming both the lead β-lactam and CA inhibitor drugs (MIC values in the range 0.25 to 0.5 μg/mL).

The Enterococcus secretome inhibits the growth of vancomycin-resistant Enterococcus faecalis V853 with their antiproliferative properties and nanoencapsulation effects.

In our study, the secretome of the clinical isolate Enterococcus faecalis HY7 displayed antibacterial activity against the vancomycin-resistant Enterococcus faecalis V853. These bacteriocin-like substances showed thermal stability at a wide range of temperatures up to 121°C, while proteinase K treatment resulted in a total loss of their activity. PCR-based screening for bacteriocin biosynthetic genes revealed that Enterococcus faecalis HY7 harbored multiple enterocin-producing genes, including ent A, avc A, and as-48. The production kinetics demonstrated the highest levels of bacteriocins production at 16h, whereas the activity was diminished after 32h of microbial growth. Notably, the partially purified bacteriocins exhibited anti-proliferative activity on the colon cancer cells, Caco2, with an IC50 value of 172.8μg/mL. Remarkably, the nanoencapsulation of our bacteriocins in liposome showed a fourfold increase in its anti-vancomycin-resistant Enterococcus activity, which is the first report of liposome encapsulation with anti-vancomycin resistant Enterococcus bacteriocin.

Synthetic antimicrobial peptides: activity against vancomycin-resistant Enterococcus faecalis and modulation of chloramphenicol antibacterial activity.

Enterococcus faecalis (E. faecalis) is a leading cause of nosocomial infection and presents a wide spectrum of antibiotic resistance, being vancomycin-resistant Enterococcus (VRE) one of the most relevant. Synthetic antimicrobial peptides (SAMPs) are currently a promising option to overcome antimicrobial resistance. Thus, the purpose of this study was to assess the effect of eight SAMPs against vancomycin-resistant E. faecalis, as well as to investigate their mechanism of action and synergy with conventional antibiotics. Here, eight SAMPs, Mo-CBP3-PepI, Mo-CBP3-PepII, Mo-CBP3-PepIII, RcAlb-PepI, RcAlb-PepII, RcAlb-PepIII, PepGAT, and PepKAA, were tested for antibacterial activity in vitro against E. faecalis (ATCC® 51299) through broth microdilution. A maximum of 48% of E. faecalis growth inhibition was achieved by treatment with SAMPs alone. However, when these peptides were combined with the antibiotic chloramphenicol, assessed by checkerboard method, the inhibition increased to 55%-76% of inhibition, two to three-folds of increase if compared to the effects of the compounds alone. Microscopic analysis showed that E. faecalis cells treated with a combination of SAMPs and chloramphenicol resulted in bacterial membrane damage. The biofilm inhibition maximum was 22% for SAMPs alone, when combined with chloramphenicol, the maximum increased to 33%. SAMPs and their combination with chloramphenicol demonstrate antibacterial activity against E. faecalis, possibly by inducing bacterial membrane damage.

Long-Term Outcomes Associated With β-Lactam Allergies

β-lactam (BL) allergies are the most common drug allergy worldwide, but most are reported in error. BL allergies are also well-established risk factors for adverse drug events and antibiotic-resistant infections during inpatient health care encounters, but the understanding of the long-term outcomes of patients with BL allergies remains limited. To evaluate the long-term clinical outcomes of patients with BL allergies. This longitudinal retrospective cohort study was conducted at a single regional health care system in western Pennsylvania. Electronic health records were analyzed for patients who had an index encounter with a diagnosis of sepsis, pneumonia, or urinary tract infection between 2007 and 2008. Patients were followed-up until death or the end of 2018. Data analysis was performed from January 2022 to January 2024. The presence of any BL class antibiotic in the allergy section of a patient's electronic health record, evaluated at the earliest occurring observed health care encounter. The primary outcome was all-cause mortality, derived from the Social Security Death Index. Secondary outcomes were defined using laboratory and microbiology results and included infection with methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile, or vancomycin-resistant Enterococcus (VRE) and severity and occurrence of acute kidney injury (AKI). Generalized estimating equations with a patient-level panel variable and time exposure offset were used to evaluate the odds of occurrence of each outcome between allergy groups. A total of 20 092 patients (mean [SD] age, 62.9 [19.7] years; 12 231 female [60.9%]), of whom 4211 (21.0%) had BL documented allergy and 15 881 (79.0%) did not, met the inclusion criteria. A total of 3513 patients (17.5%) were Black, 15 358 (76.4%) were White, and 1221 (6.0%) were another race. Using generalized estimating equations, documented BL allergies were not significantly associated with the odds of mortality (odds ratio [OR], 1.02; 95% CI, 0.96-1.09). BL allergies were associated with increased odds of MRSA infection (OR, 1.44; 95% CI, 1.36-1.53), VRE infection (OR, 1.18; 95% CI, 1.05-1.32), and the pooled rate of the 3 evaluated antibiotic-resistant infections (OR, 1.33; 95% CI, 1.30-1.36) but were not associated with C difficile infection (OR, 1.04; 95% CI, 0.94-1.16), stage 2 and 3 AKI (OR, 1.02; 95% CI, 0.96-1.10), or stage 3 AKI (OR, 1.06; 95% CI, 0.98-1.14). Documented BL allergies were not associated with the long-term odds of mortality but were associated with antibiotic-resistant infections. Health systems should emphasize accurate allergy documentation and reduce unnecessary BL avoidance.

Multidrug-Resistant Bacteria in Surgical Intensive Care Units: Antibiotic Susceptibility and β-Lactamase Characterization.

Multidrug-resistant (MDR) bacteria of the utmost importance are extended-spectrum β-lactamase (ESBL) and carbapenemase-producing Enterobacterales (CRE), carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp. (VRE). In this study, an evaluation of MDR bacteria in surgical intensive care units in a tertiary referral hospital was conducted. The study aimed to characterize β-lactamases and other resistance traits of Gram-negative bacteria isolated in surgical intensive care units (ICUs). Disk diffusion and the broth dilution method were used for antibiotic susceptibility testing, whereas ESBL screening was performed through a double disk synergy test and an inhibitor-based test with clavulanic acid. A total of 119 MDR bacterial isolates were analysed. ESBL production was observed in half of the Proteus mirabilis, 90% of the Klebsiella pneumoniae and all of the Enterobacter cloacae and Escherichia coli isolates. OXA-48 carbapenemase, carried by the L plasmid, was detected in 34 K. pneumoniae and one E. coli and Enterobacter cloacae complex isolates, whereas NDM occurred sporadically and was identified in three K. pneumoniae isolates. OXA-48 positive isolates coharboured ESBLs belonging to the CTX-M family in all but one isolate. OXA-23 carbapenemase was confirmed in all A. baumannii isolates. The findings of this study provide valuable insight of resistance determinants of Enterobacterales and A. baumannii which will enhance surveillance and intervention strategies that are necessary to curb the ever-growing carbapenem resistance rates.

Which trial do we need? Gown and glove use versus standard precautions for patients colonized or infected with methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus

Which trial do we need? Gown and glove use versus standard precautions for patients colonized or infected with methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus

Bacterial Colonization of Mobile Phones: Myth or Reality.

Introduction Bacteria tend to persist on mobile phones for longer durations causing hospital-acquired infections. This is primarily because mobile phones have become an extended hand to healthcare workers due to their unavoidable utilization and the lack of sanitization after use in wards. Methods A questionnaire was used to assess the usage and disinfection practices of mobile phones among medical students regularly attending the wards of a teaching hospital. Culture was done to assess the presence of bacteria and their resistance to antibiotics. Three sterile cotton swabs were performed for each mobile phone. If growth was present, then a culture smear was made, and the type of bacteria was assessed. Participants received subsequent education on the disinfection of phones according to standard disinfection protocol. The main objective of the study was to determine the presence of bacteria on students' mobile phones and its resistance to antibiotics. Results A total of 103 medical students took part in the study, which included 51 males and 52 females. It was found that all the students used their mobile phones at all times in wards and 43% of them carried their phones to washrooms. Out of all the students surveyed, only 23% of students had regularly disinfected their phones. Bacteria were present on all mobile phones sampled. Among these, 98.05% had Gram-positive bacteria, 82.52% had Gram-negative bacilli, 33.98% had Bacillaceae, and 8.73% had vancomycin-resistant enterococcus (VRE). Among participants who did not disinfect their phones, 95.89% and 97.59% had methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA), respectively. Conclusion Following standard disinfection protocols is the need of the hour to reduce hospital-acquired infections.

Functional dependence as a contributing factor for patient hand contamination by multi-drug resistant organisms (MDROs) in acute care.

Patient hands' contribution to disease transmission in healthcare settings is an important, understudied topic. We assessed correlation between patient functional dependence and hand contamination with multi-drug resistant organisms (MDROs) in acute-care settings. Secondary, cross-sectional analyses of 399 general medicine patients enrolled in two tertiary-care hospitals over a six-month period. Our predictor was patient functional status evaluated using Katz Activities of Daily Living scale, scored as follows: functionally independent (scored 0), moderately dependent (score 1-3), and severely dependent (score of 4 or more). Our outcome was patient hand contamination with MDROs, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus, and resistant gram-negative bacteria. Of 399 patients, 298 were functionally independent, 45 were moderately dependent, and 56 were severely dependent. Odds of MDRO hand contamination were 2.63 (95% CI, 1.21-5.72) times higher in the severely dependent category compared to the independent category. Patients with feeding dependence had the highest odds of hand contamination with MDROs (OR 4.76, 95% CI, 1.54-14.71), followed by continence, dressing, and toileting. In addition to patient colonization, environmental contamination with MRSA was associated with patient function, with odds 2.60 (95% CI, 1.16-5.82) times higher in severely dependent patients. Patients with severe functional dependence are more likely to harbor MDROs on their hands and less likely to be able to cleanse them independently. Functionally dependent patients have high room contamination with MDROs. Patient hand hygiene interventions in the hospital should target this high-risk group.

Copper-phenolic coating constructed on silicone urinary catheters to prevent catheter-associated infections

Catheter-associated infections (CAIs) are serious issues in clinics, significantly affecting patient morbidity, mortality, and incurring substantial treatment costs. Hence, the development of a novel strategy to endow surfaces with antibacterial function is particularly important for catheter materials. In this work, Tannic acid (TA) and various concentrations of copper (Cu) were used to construct metal-phenolic network (MPN) coatings to impart silicone catheters antibacterial surfaces (TA/Cu5, TA/Cu5 and TA/Cu25). The prepared copper-phenolic coatings exhibited desirable biocompatibility towards mammalian cells and remarkable antibacterial properties against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and even “superbug” such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). The antibacterial properties of the MPN coatings were attributed to the combined effects of Cu and TA. Among all MPN coated silicone catheters, TA/Cu25 (10 mM TA and 250 mM CuCl2·2 H2O) exhibited the highest antibacterial activity with killing ratios of 99.84%, 98.67%, 99.85%, and 99.90% against S. aureus, E. Coli, MRSA and VRE, respectively. Thus, the MPN has significant potential for developing antibacterial surface coatings for silicone catheters, which can effectively mitigate CAIs.

Antibacterial Activity and Action Mechanism of Bacteriocin Paracin wx7 as a Selective Biopreservative against Vancomycin-Resistant Enterococcus faecalis in Fresh-Cut Lettuce.

Fresh-cut vegetables are widely consumed, but there is no food preservative available to selectively inhibit vancomycin-resistant E. faecalis, which is a serious health menace in fresh-cut vegetables. To develop a promising food biopreservative, a bacteriocin, paracin wx7, was synthesized, showing selective inhibition against E. faecalis with MIC values of 4-8 μM. It showed instant bactericidal mode within 1 h at high concentrations with concomitant cell lysis against vancomycin-resistant E. faecalis. Its lethal effect was visualized in a dose-dependent manner by PI/SYTO9 staining observation. The results of an in vivo control experiment carried out on E. faecalis in fresh-cut lettuce showed that 99.97% of vancomycin-resistant E. faecalis were dead after 64 μM paracin wx7 treatment for 7 days without influencing total bacteria. Further, the action mechanism of paracin wx7 was investigated. Confocal microscopy showed that paracin wx7 was located both on the cell envelope and in cytoplasm. For the cell envelope, the studies of membrane permeability using SYTOX Green dyeing and DNA leakage revealed that paracin wx7 damaged the membrane integrity of E. faecalis. Simultaneously, it exhibited membrane depolarization after analysis using DiSC3(5). Damage to the cell envelope resulted in cell deformation observed by scanning electron microscopy. On entering the cytoplasm, the paracin wx7 induced the production of endogenous reactive oxygen species.

Prevalence of Vancomycin Resistant Enterococcus in Various Clinical Specimens in Tertiary Care Hospital

Prevalence of Vancomycin Resistant Enterococcus in Various Clinical Specimens in Tertiary Care Hospital