Vancomycin-Resistant Enterococci: Epidemiology, Infection Prevention, and Control

Antimicrobial and anti-biofilm activity of a thiazolidinone derivative against Staphylococcus aureus in vitro and in vivo

Staphylococcus aureus (S. aureus) causes many infections with significant morbidity and mortality. S. aureus can form biofilms, which can cause biofilm-associated diseases and increase resistance to many conventional antibiotics, resulting in chronic infection. It is critical to develop novel antibiotics against staphylococcal infections, particularly those that can kill cells embedded in biofilms. This study aimed to investigate the bacteriocidal and anti-biofilm activities of thiazolidinone derivative (TD-H2-A) against S. aureus. A total of 40 non-duplicate strains were collected, and the minimum inhibitory concentrations (MICs) of TD-H2-A were determined. The effect of TD-H2-A on established S. aureus mature biofilms was examined using a confocal laser scanning microscope (CLSM). The antibacterial effects of the compound on planktonic bacteria and bacteria in mature biofilms were investigated. Other characteristics, such as cytotoxicity and hemolytic activity, were researched. A mouse skin infection model was used, and a routine hematoxylin and eosin (H&E) staining was used for histological examination. The MIC values of TD-H2-A against the different S. aureus strains were 6.3-25.0 µg/mL. The 5 × MIC TD-H2-A killed almost all planktonic S. aureus USA300. The derivative was found to have strong bacteriocidal activity against cells in mature biofilms meanwhile having low cytotoxicity and hemolytic activity against Vero cells and human erythrocytes. TD-H2-A had a good bacteriocidal effect on S. aureus SA113-infected mice. In conclusion, TD-H2-A demonstrated good bacteriocidal and anti-biofilm activities against S. aureus, paving the way for the development of novel agents to combat biofilm infections and multidrug-resistant staphylococcal infections.IMPORTANCEStaphylococcus aureus, a notorious pathogen, can form a stubborn biofilm and develop drug resistance. It is crucial to develop new anti-infective therapies against biofilm-associated infections. The manuscript describes the new antibiotic to effectively combat multidrug-resistant and biofilm-associated diseases.

Factors affecting vancomycin-resistant Enterococcus faecium colonization of in-hospital patients in different wards

Objectives

The prevalence of vancomycin-resistant Enterococcus faecium (VRE) infection at a medical center in Eastern Taiwan rose to 80.6%, exceeding the average prevalence of 55.6% among all medical centers nationwide during the same period. In recent years, the number of cases of VRE infection detected among hospitalized patients has increased annually. However, most of these patients in different wards are asymptomatic carriers. Therefore, restricting active screening to high-risk units will not improve the current situation, and it is necessary to review the risk factors for VRE colonization to provide a reference for future infection control policies.

Materials and Methods

Between 2014 and 2019, there were 3188 VRE-positive cultures reported at our institution, as per the electronic medical records system.

Results

In the medical and surgical wards, patients who received penicillin (odds ratios [ORs]: 2.84 and 4.16, respectively) and third-generation cephalosporins (ORs: 3.17 and 6.19, respectively) were at higher risk of VRE colonization. In intensive care units, the use of carbapenems (OR: 2.08) was the most significant variable.

Conclusion

This study demonstrated that the risk factors for VRE colonization differed between wards. Thus, policies should be established according to the attributes of patients in each ward, and active screening tests should be performed according to individual risks, instead of a policy for comprehensive mass screening.

Microbiota-mediated colonization resistance: mechanisms and regulation

A dense and diverse microbial community inhabits the gut and many epithelial surfaces. Referred to as the microbiota, it co-evolved with the host and is beneficial for many host physiological processes. A major function of these symbiotic microorganisms is protection against pathogen colonization and overgrowth of indigenous pathobionts. Dysbiosis of the normal microbial community increases the risk of pathogen infection and overgrowth of harmful pathobionts. The protective mechanisms conferred by the microbiota are complex and include competitive microbial-microbial interactions and induction of host immune responses. Pathogens, in turn, have evolved multiple strategies to subvert colonization resistance conferred by the microbiota. Understanding the mechanisms by which microbial symbionts limit pathogen colonization should guide the development of new therapeutic approaches to prevent or treat disease.

Infant food production environments: A potential reservoir for vancomycin-resistant enterococci non-nosocomial infections

Enterococcus has been considered one of the most important nosocomial pathogens for human infections, and the hospital environment is an important reservoir for vancomycin-resistant enterococci (VRE) that leads to antimicrobial therapeutic failure. However, infant foods and their production environments could pose risks for the immature population, while this question remains unaddressed. This study conducted an extensive and thorough Enterococcus isolation, VRE risk assessment of the Chinese infant food production chains and additional online-marketing infant foods, including powdered infant formula (PIF) and infant complementary food (ICF). To investigate the prevalence of Enterococcus along infant food chains and commodities, a total of 482 strains of Enterococcus, including E. faecium (n = 363), E. faecalis (n = 84), E. casseliflavus (n = 13), E. mundtii (n = 12), E. gallinarum (n = 4), E. hirae (n = 4), and E. durans (n = 2) were recovered from 459 samples collected from infant food production chains (71/254) and food commodities (67/205). A decreasing trend for Enterococcus detection rate was found in the PIF production chain (PIF-PC), particularly during the preparation of the PIF base powder (From 100 % in raw milk to 8.70 % in end products), while an increasing trend was observed in the ICF production chain (ICF-PC) mainly during the initial processing of farm crops and the further processing of the product (20 % at farm crops increasing to 76.92 % at end products). The result indicated that the PIF-PC process effectively reduced Enterococcus contamination, while the ICF-PC showed the opposite trend. Importantly, eleven VRE isolates were recovered from the infant food production chain, including seven E. casseliflavus isolates carrying vanC2/C3 and four E. gallinarum isolates carrying vanC1. Ten VRE isolates were from food production environments. Collectively, our study demonstrated that infant food production environments represent potential reservoirs for VRE non-nosocomial infections in vulnerable populations.

Vancomycin and Linezolid-Resistant Enterococcus Isolates from a Tertiary Care Center in India

INTRODUCTION

There is increasing development of antibiotic resistance among the Enterococcus species.

OBJECTIVES

This study was performed to determine prevalence and characterize the vancomycin-resistant and linezolid-resistant enterococcus isolates from a tertiary care center. Moreover, the antimicrobial susceptibility pattern of these isolates was also determined.

MATERIALS AND METHODS

A prospective study was performed in Medical College, Kolkata, India, over a period of two years (from January 2018 to December 2019). After obtaining clearance from the Institutional Ethics Committee, Enterococcus isolates from various samples were included in the present investigation. In addition to the various conventional biochemical tests, the VITEK 2 Compact system was used to identify the Enterococcus species. The isolates were tested for antimicrobial susceptibility to different antibiotics using the Kirby-Bauer disk diffusion method and VITEK 2 Compact to determine the minimum inhibitory concentration (MIC). The Clinical and Laboratory Standards Institute (CLSI) 2017 guidelines were used to interpret susceptibility. Multiplex PCR was performed for genetic characterization of the vancomycin-resistant Enterococcus isolates and sequencing was performed for characterization of the linezolid-resistant Enterococcus isolates.

RESULTS

During the period of two years, 371 isolates of Enterococcus spp. were obtained from 4934 clinical isolates showing a prevalence of 7.52%. Among these isolates, 239 (64.42%) were Enterococcus faecalis, 114 (30.72%) Enterococcus faecium, and others were Enterococcus durans, Enterococcus casseliflavus, Enterococcus gallinarum, and Enterococcus avium. Among these, 24 (6.47%) were VRE (Vancomycin-Resistant Enterococcus) of which 18 isolates were Van A type and six isolates of Enterococcus casseliflavus and Enterococcus gallinarum were resistant VanC type. There were two linezolid-resistant Enterococcus, and they were found to have the G2576T mutation. Among the 371 isolates, 252 (67.92%) were multi-drug resistant.

CONCLUSION

This study found an increasing prevalence of vancomycin-resistant Enterococcus isolates. There is also an alarming prevalence of multidrug resistance among these isolates.

Herbal Products and Their Active Constituents Used Alone and in Combination with Antibiotics against Multidrug-Resistant Bacteria

The purpose of this review is to summarize the current knowledge acquired on herbal products and their active constituents with antimicrobial activity used alone and in combination with antibiotics against multidrug-resistant bacteria. The most promising herbal products and active constituents used alone against multidrug-resistant bacteria are Piper betle (methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, extended-spectrum beta-lactamase, Acinetobacter baumannii, Pseudomonas aeruginosa), Glycyrrhiza glabra (methicillin-resistant S. aureus, vancomycin-resistant Enterococcus, P. aeruginosa), and berberine (methicillin-resistant S. aureus, A. baumannii, P. aeruginosa), respectively. The synergistic effect of the combination of herbal products and their active constituents with antibiotics against multidrug-resistant bacteria are also described. These natural antibacterial agents can be promising sources of inhibitors, which can modulate antibiotic activity against multidrug-resistant bacteria, especially as efflux pump inhibitors. Other possible mechanisms of action of herbal therapy against multidrug-resistant bacteria including modification of the bacterial cell wall and/or membrane, inhibition of the cell division protein filamenting temperature sensitive Z-ring, and inhibition of protein synthesis and gene expression, all of which will also be discussed. Our review suggests that combination herbal therapy and antibiotics can be effectively used to expand the spectrum of their antimicrobial action. Therefore, combination therapy against multidrug-resistant bacteria may enable new choices for the treatment of infectious diseases and represents a potential area for future research.

Loss of erm(B)-Mediated rRNA Dimethylation and Restoration of Erythromycin Susceptibility in Erythromycin-Resistant Enterococci Following Induced Linezolid Resistance

Linezolid has been reported to restore erythromycin susceptibility in erythromycin-resistant Staphylococcus aureus. This phenomenon has not been reported in enterococci and the mechanisms involved therein are still unknown. The purpose of this study was to investigate the mechanisms involved and the effect of combining linezolid with erythromycin on erythromycin-resistant enterococci. Checkerboard techniques were used to determine drug interactions, and 12 of 14 isolates showed a synergistic effect between erythromycin and linezolid (fractional inhibitory concentration <0.5). We observed that the erm(B) gene, which encodes a dimethyltransferase responsible for erythromycin resistance, was expressed from transposon Tn1545 in the tested erythromycin-resistant enterococci. After exposure to linezolid, erm(B)-mediated rRNA dimethylation at A2071 could not be detected, and the erm(B) gene was lost following acquisition of erythromycin susceptibility. Thus, in conclusion, linezolid combined with erythromycin exerts a synergistic effect against erythromycin-resistant enterococci. Linezolid treatment suppressed erm(B)-mediated rRNA dimethylation at A2071, which could lead to loss of the erm(B) gene.

Should Perirectal Swab Culture Be Performed in Cases Admitted to the Neonatal Intensive Care Unit? Lessons Learned from the Neonatal Intensive Care Unit

Serial perirectal swabs are used to identify colonization of multidrug-resistant bacteria and prevent spread. The purpose of this study was to determine colonization with carbapenem-resistant Enterobacterales (CRE) and vancomycin-resistant Enterococci (VRE). An additional purpose was to establish whether sepsis and epidemic associated with these factors were present in the neonatal intensive care unit (NICU), to which infants with hospital stays exceeding 48 h in an external healthcare center NICU were admitted. Perirectal swab samples were collected in the first 24 h by a trained infection nurse using sterile cotton swabs moistened with 0.9% NaCl from patients admitted to our unit after hospitalization exceeding 48 h in an external center. The primary outcome was positivity in perirectal swab cultures, and the secondary outcomes were whether this caused invasive infection and significant NICU outbreaks. A total of 125 newborns meeting the study criteria referred from external healthcare centers between January 2018 and January 2022 were enrolled. Analysis revealed that CRE constituted 27.2% of perirectal swab positivity and VRE 4.8%, and that one in every 4.4 infants included in the study exhibited perirectal swab positivity. The detection of colonization by these microorganisms, and including them within the scope of surveillance, is an important factor in the prevention of NICU epidemics.

Multidrug-Resistant Enterococcal Infection in Surgical Patients, What Surgeons Need to Know

Enterococci are organisms that can be found in the normal intestinal and skin microbiota and show remarkable ability to acquire antibiotic resistance. This is an enormous challenge for surgeons when faced with surgical site infections caused by multidrug-resistant (MDR) Enterococci. Due to an increase in the prevalence of MDR Enterococcus within the last few decades, there has been a major decrease in therapeutic options, because the majority of E. faecium isolates are now resistant to ampicillin and vancomycin and exhibit high-level resistance to aminoglycosides, traditionally three of the most useful anti-enterococcal antibiotics. There is limited data regarding the magnitude and pattern of multidrug resistance among the enterococcal genus causing surgical site infections in hospitalized patients. The scope of the review is to summarize the most recent findings in the emergence of postoperative MDR Enterococci and discuss recent mechanisms of resistance and the best treatment options available.

Reporting antimicrobial susceptibilities and phenotypes of resistance to vancomycin in vancomycin-resistant Enterococcus spp. clinical isolates: A nationwide proficiency study

INTRODUCTION

The ability of Spanish microbiology laboratories to (a) determine antimicrobial susceptibility (AS), and (b) correctly detect the vancomycin resistance (VR) phenotype in vancomycin-resistant Enterococcus spp. (VRE) was evaluated.

METHODS

Three VRE isolates representing the VanA (E. faecium), VanB (E. faecium) and VanC (E. gallinarum) VR phenotypes were sent to 52 laboratories, which were asked for: (a) AS method used; (b) MICs of ampicillin, imipenem, vancomycin, teicoplanin, linezolid, daptomycin, ciprofloxacin, levofloxacin and quinupristin-dalfopristin, and high-level resistance to gentamicin and streptomycin; (c) VR phenotype.

RESULTS

(a) The most frequently used system was MicroScan; (b) according to the system, the highest percentage of discrepant MICs was found with gradient strips (21.3%). By antimicrobial, the highest rates of discrepant MICs ranged 16.7% (imipenem) to 0.7% (linezolid). No discrepant MICs were obtained with daptomycin or levofloxacin. Mayor errors (MEs) occurred with linezolid (1.1%/EUCAST) and ciprofloxacin (5.0%/CLSI), and very major errors (VMEs) with vancomycin (27.1%/EUCAST and 33.3%/CLSI) and teicoplanin (5.7%/EUCAST and 2.3%/CLSI). For linezolid, ciprofloxacin, and vancomycin, discrepant MICs were responsible for these errors, while for teicoplanin, errors were due to a misassignment of the clinical category. An unacceptable high percentage of VMEs was obtained using gradient strips (14.8%), especially with vancomycin, teicoplanin and daptomycin; (c) 86.4% of the centers identified VanA and VanB phenotypes correctly, and 95.0% the VanC phenotype.

CONCLUSION

Most Spanish microbiology laboratories can reliably determine AS in VRE, but there is a significant percentage of inadequate interpretations (warning of false susceptibility) for teicoplanin in isolates with the VanB phenotype.

Exogenous D-ribose promotes gentamicin treatment of several drug-resistant Salmonella

The metabolic microenvironment of bacteria impacts drug efficacy. However, the metabolic mechanisms of drug-resistant Salmonella spp. remain largely unknown. This study characterized the metabolic mechanism of gentamicin-resistant Salmonella Choleraesuis and found that D-ribose increased the gentamicin-mediated killing of this bacteria. Non-targeted metabolomics of homologous gentamicin-susceptible Salmonella Choleraesuis (SCH-S) and gentamicin-resistant S. Choleraesuis (SCH-R) was performed using UHPLC-Q-TOF MS. The metabolic signature of SCH-R included disrupted central carbon metabolism and energy metabolism, along with dysregulated amino acid and nucleotide metabolism, vitamin and cofactor metabolism, and fatty acid synthesis. D-ribose, the most suppressed metabolite in SCH-R, was shown to strengthen gentamicin efficacy against SCH-R and a clinically isolated multidrug-resistant strain. This metabolite had a similar impact on Salmonella. Derby and Salmonella. Typhimurium. D-ribose activates central carbon metabolism including glycolysis, the pentose phosphate pathway (PPP), and the tricarboxylic acid cycle (TCA cycle), increases the abundance of NADH, polarizes the electron transport chain (ETC), and elevates the proton motive force (PMF) of cells, and induces drug uptake and cell death. These findings suggest that central carbon metabolism plays a critical role in the acquisition of gentamicin resistance by Salmonella, and that D-ribose may serve as an antibiotic adjuvant for gentamicin treatment of resistant bacterial infections.

Fecal carriage of vanB antibiotic resistance gene affects adipose tissue function under vancomycin use

Detrimental consequences of antibiotic treatment may include long-lasting disruption of the gut microbiota. Previous studies found no negative effects of antibiotics on metabolic health, although individualized responses were observed. Here, we aimed to investigate the subject-specific response to vancomycin use in tissue-specific insulin sensitivity by stratifying individuals based on the presence of antibiotic resistance genes (ARGs) or opportunistic pathogens (OPs) in the baseline fecal microbiota. Quantitative Polymerase Chain Reaction (qPCR) was used to detect ARGs and OPs in DNA isolated from fecal samples of 56 males with overweight/obesity (Body Mass Index: 25-35 kg/m²) and impaired glucose metabolism (fasting plasma glucose ≥5.6 mmol/L and/or 2-hour glucose 7.8-11.1 mmol/L). A two-step hyperinsulinemic-euglycemic clamp was performed to determine tissue-specific insulin sensitivity. Abdominal subcutaneous adipose tissue (AT) gene expression was assessed using Affymetrix microarray. Gut microbial composition was determined using the Human Intestinal Tract Chip (HITChip) microarray. At baseline, the vancomycin resistance gene vanB was present in 60% of our population. In individuals that were vanB-negative at baseline, AT insulin sensitivity (insulin-mediated suppression of plasma free fatty acids) improved during vancomycin use, while it decreased among vanB-positive individuals (% change post versus baseline: 14.1 ± 5.6 vs. -6.7 ± 7.5% (p = .042)). The vancomycin-induced increase in AT insulin sensitivity was accompanied by downregulation of inflammatory pathways and enrichment of extracellular matrix remodeling pathways in AT. In the vanB-positive group, well-known vanB-carrying bacteria, Enterococcus and Streptococcus, expanded in the gut microbiome. In conclusion, microbiome composition and adipose tissue biology were differentially affected by vancomycin treatment based on fecal vanB carriage.

Antimicrobial Resistance in New Zealand-A One Health Perspective

Antimicrobial resistance (AMR) is an increasing global threat that affects human, animal and, often less acknowledged, environmental health. This complex issue requires a multisectoral One Health approach to address the interconnectedness of humans, animals and the natural environment. The prevalence of AMR in these reservoirs varies widely among countries and thus often requires a country-specific approach. In New Zealand (NZ), AMR and antimicrobial usage in humans are relatively well-monitored and -understood, with high human use of antimicrobials and the frequency of resistant pathogens increasing in hospitals and the community. In contrast, on average, NZ is a low user of antimicrobials in animal husbandry systems with low rates of AMR in food-producing animals. AMR in New Zealand’s environment is little understood, and the role of the natural environment in AMR transmission is unclear. Here, we aimed to provide a summary of the current knowledge on AMR in NZ, addressing all three components of the One Health triad with a particular focus on environmental AMR. We aimed to identify knowledge gaps to help develop research strategies, especially towards mitigating AMR in the environment, the often-neglected part of the One Health triad.

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.

Effective Treatment of Skin Wounds Co-Infected with Multidrug-Resistant Bacteria with a Novel Nanoemulsion

Wound infections with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) are particularly difficult to treat and present a great challenge to clinicians. Nanoemulsions (NE) are novel oil-in-water emulsions formulated from soybean oil, water, solvent, and surfactants such as benzalkonium chloride (BZK). An optimal ratio of those components produces nanometer-sized particles with the positive-charged surfactant at their oil-water interface. We sought to investigate antimicrobial NE as a novel treatment to address wounds co-infected by MRSA and VRE. Swine split-thickness skin wounds were first infected with MRSA and/or VRE, then treated with the nanoemulsion formulation (X-1735) or placebo controls. Bacterial viability after treatment were determined by nutrient agar plates for total, MRSA-specific, and VRE-specific loads. In addition, inflammation indexes were scored by histopathology. When VRE infected wounds were treated with X-1735, they contained 103 lower VRE CFU counts across a 2-week period compared with placebo. Once co-infected MRSA and VRE split-thickness wounds were successfully established, topical treatment of co-infected wounds with X-1735 resulted in a reduction of bacteria by 2 to 3 logs (compared with placebo) at 3- and 14-day postinfection time points. Importantly, X-1735 was effective in significantly alleviating multilevel inflammation in the treated wounds. X-1735 is a new antimicrobial that is safe to apply to open wounds and effectively kills MRSA and VRE. It appears to also reduce inflammation in these co-infected wounds. The data suggest that this approach offers promise as an antimicrobial for open wounds with MRSA and VRE co-infection. IMPORTANCE Infections, specifically polymicrobial, can cause serious consequences when it comes to wound treatment. Prolonged treatment with antibiotics can lead to an increased risk of bacterial resistance; co-infections can complicate treatment options even further. Our research proposes a novel nanoemulsion treatment for two of the most common antibiotic resistant bacteria: methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant enterococci (VRE). This optimized topical treatment formulation not only significantly reduces inflammation and infection in MRSA or VRE infected wounds, but also in MRSA and VRE co-infected wounds as well. The work aims to provide an alternative treatment approach for multidrug-resistant organisms and decrease dependence on systemic treatments.

Enterococcus raffinosus, Enterococcus durans and Enterococcus avium Isolated from a Tertiary Care Hospital in Romania-Retrospective Study and Brief Review

(1) Background: This paper aims to provide a description of non-faecalis non-faecium enterococci isolated from a tertiary care hospital in Romania and to briefly review the existing literature regarding the involvement of Enterococcus raffinosus, Enterococcus durans and Enterococcus avium in human infections and their antimicrobial resistance patterns; (2) Methods: We retrospectively analyzed all Enteroccocus species isolated from the “Prof. Dr. O. Fodor” Regional Institute of Gastroenterology and Hepatology from Cluj-Napoca during one year focusing on non-faecalis non-faecium Enterococci. A brief review of the literature was performed using case reports involving Enterococcus raffinosus, Enterococcus durans and Enterococcus avium; (3) Results: Only 58 out of 658 Enteroccocus isolates were non-faecalis non-faecium and met the inclusion criteria. These species were isolated more often (p < 0.05) from the surgical ward from mixed etiology infections with E. coli. In our review, we included 39 case reports involving E. raffinosus, E. durans and E. avium; (4) Conclusions: Isolation of non-faecalis non-faecium enterococci displays an emerging trend with crucial healthcare consequences. Based on the analysis of the case reports, E. avium seems to be involved more often in neurological infections, E. durans in endocarditis, while E. raffinosus displays a more heterogenous distribution.

Impact of infectious diseases consultation on the outcome of patients with enterococcal bacteremia: a systematic literature review and meta-analysis

Background

Enterococcal bacteremia carries significant mortality. While multiple studies have evaluated the impact of infectious disease consultation (IDC) on this condition, these studies were limited by the low numbers of patients enrolled. This systemic literature review and meta-analysis were conducted to determine whether IDC was associated with a mortality benefit among patients with enterococcal bacteremia.

Methods

We performed a systematic literature search using 5 databases for studies evaluating IDC among patients with enterococcal bacteremia. We conducted a meta-analysis to assess whether IDC was associated with reduced mortality. Random-effect models were used to calculated pooled odds ratios (pORs). Heterogeneity was evaluated using I2 estimation and the Cochrane Q statistic test.

Results

The systemic literature review revealed 6496 reports, from which 18 studies were evaluated in the systemic literature review and 16 studies in the meta-analysis. When all studies were pooled, the association between IDC and mortality was not statistically significant with a pOR of 0.81 (95% CI, 0.61-1.08) and there was substantial heterogeneity (I2=58%). When the studies were limited to those reporting multivariate analysis including IDC, there was a significant protective effect of IDC (pOR=0.40; 95% CI, 0.24-0.68) without heterogeneity (I2=0%). Some studies also showed additional benefits to IDC, including appropriate antibiotic therapy, and improved diagnostic use.

Conclusions

IDC was associated with 60% lower odds of mortality when patients were well-matched, potentially through improvement in the care for patients with enterococcal bacteremia. IDC should be considered a part of routine care for patients with enterococcal bacteremia.

In Vitro Screening of a 1280 FDA-Approved Drugs Library against Multidrug-Resistant and Extensively Drug-Resistant Bacteria

Alternative strategies against multidrug-resistant (MDR) bacterial infections are suggested to clinicians, such as drug repurposing, which uses rapidly available and marketed drugs. We gathered a collection of MDR bacteria from our hospital and performed a phenotypic high-throughput screening with a 1280 FDA-approved drug library. We used two Gram positive (Enterococcus faecium P5014 and Staphylococcus aureus P1943) and six Gram negative (Acinetobacter baumannii P1887, Klebsiella pneumoniae P9495, Pseudomonas aeruginosa P6540, Burkholderia multivorans P6539, Pandoraea nosoerga P8103, and Escherichia coli DSM105182 as the reference and control strain). The selected MDR strain panel carried resistance genes or displayed phenotypic resistance to last-line therapies such as carbapenems, vancomycin, or colistin. A total of 107 compounds from nine therapeutic classes inhibited >90% of the growth of the selected Gram negative and Gram positive bacteria at a drug concentration set at 10 µmol/L, and 7.5% were anticancer drugs. The common hit was the antiseptic chlorhexidine. The activity of niclosamide, carmofur, and auranofin was found against the selected methicillin-resistant S. aureus. Zidovudine was effective against colistin-resistant E. coli and carbapenem-resistant K. pneumoniae. Trifluridine, an antiviral, was effective against E. faecium. Deferoxamine mesylate inhibited the growth of XDR P. nosoerga. Drug repurposing by an in vitro screening of a drug library is a promising approach to identify effective drugs for specific bacteria.

Nosocomial Infection and Antibiotic-Resistant Threat in the Middle East

The prevalence of nosocomial infections (NIs) is associated with different bacteria found in hospitals. These infections in their extreme conditions result in morbidity and mortality. This study aims to provide a detailed review of literary studies to identify the prevalence of nosocomial infections and antibiotic-resistance specifically in Middle Eastern countries. A literature review approach is followed in this study. It further identifies different causes and effects associated with nosocomial infections in the given regions. Relevant studies were used to extract important information, specifically related to the Middle Eastern countries. The findings indicated that nosocomial infections following antibiotic resistance are an emerging problem in Middle Eastern countries, leading to significant morbidity and mortality. Most frequently reported NIs in Middle East in our review are bloodstream infections (BSIs) (50%) and surgical site infections (SSIs) (50%) followed by urinary tract infections (UTIs). Escherichia coli and Klebsiella species among gram-negative bacteria, Staphylococcus aureus among gram-positive bacterial and fungal pathogens such as Candida species are most reported pathogens involved in nosocomial infections and resistance to penicillins, cephalosporins, carbapenems and fluoroquinolones antibiotics were significantly reported. However, most studies showed minimum resistance of pathogens against drug colistin. To control the growth rate of the given condition, government officials are suggested to ensure that hospitals follow adequate healthcare mechanisms. Also, sufficient education must be provided to the hospital staff about the causes and effects of the given disease.

Multidrug-resistant bacteria isolated from surgical site of dogs, surgeon's hands and operating room in a veterinary teaching hospital in Brazil

Surgical environment can play as a source of multidrug-resistance organism, what can pose as a big threat to the patients and health care professionals. This study aimed to evaluate the prevalence and antimicrobial resistance profile of Gram-positive cocci (GPC) and Gram-negative bacilli (GNB) isolated from the surgical environment. All samples were collected during the intraoperative period of clean/clean-contaminated (G1) and contaminated (G2) surgery. A total of 150 samples were collected from the superficial surgical site in the beginning (n=30) and the end (n=30) of the procedure, surgeon's hands before (n=30) and after (n=30) antisepsis, and the surgical environment (n=30). MALDI-TOF MS and antimicrobial susceptibility testing by disk diffusion method were performed for species identification, and determination of the resistance profile. Sixty-eight isolates of GPC and 15 of GNB were obtained. Staphylococcus spp. were the most frequent species isolated from surgical site (55.26% [21/38]), surgeon's hands (46.15% [6/13]), and environment (56.67% [17/30]). GPC were mostly resistance to penicillin (85.71% [54/63]), and erythromycin (77.78% [49/63]), and GNB were mostly resistance to cefazolin (58.33% [7/12]), and azithromycin (58.33% [7/12]). High incidence of multidrug resistance was observed in coagulase-negative staphylococci (86.21% [25/29]), coagulase-positive staphylococci (86.67% [13/15]), Enterococcus spp. (68.42% [13/19]) and Gram-negative bacilli (60% [9/15]). The high rate of resistance of commensal bacteria found in our study is worrying. Coagulase-negative staphylococci are community pathogens related to nosocomial infections in human and veterinary hospitals, their presence in healthy patients and in veterinary professionals represent an important source of infection in the one health context. Continuous surveillance and application of antimicrobial stewardship programs are essential in the fight against this threat.

Daptomycin-Resistant Enterococcus Bacteremia Is Associated with Prior Daptomycin Use and Increased Mortality after Liver Transplantation

Background

Risk factors for acquisition of vancomycin-resistant Enterococcus (VRE) include immunosuppression, antibiotic exposure, indwelling catheters, and manipulation of the gastrointestinal tract, all of which occur in liver transplant recipients. VRE infections are documented in liver transplantation (LT); however, only one single center study has assessed the impact of daptomycin-resistant Enterococcus (DRE) in this patient population.

Methods

We conducted a retrospective multicenter cohort study comparing liver transplant recipients with either VRE or DRE bacteremia. The primary outcome was death within 1 year of transplantation. Multivariable logistic regression analyses were performed to calculate adjusted odds ratios for outcomes of interest.

Results

We identified 139 cases of Enterococcus bacteremia following LT, of which 78% were VRE and 22% were DRE. When adjusted for total intensive care unit days in the first transplant year, liver-kidney transplantation, and calcineurin inhibitor use, patients with DRE bacteremia were 2.65 times more likely to die within 1 year of transplantation (adjusted odds ratio [aOR], 2.648; 95% CI, 1.025–6.840; P = .044). Prior daptomycin exposure was found to be an independent predictor of DRE bacteremia (aOR, 30.62; 95% CI, 10.087–92.955; P < .001).

Conclusions

In this multicenter study of LT recipients with Enterococcus bacteremia, DRE bacteremia was associated with higher 1-year mortality rates when compared with VRE bacteremia. Our data provide strong support for dedicated infection prevention and antimicrobial stewardship efforts for transplant patients. Further research is needed to support the development of better antibiotics for DRE and practical guidance focusing on identification and prevention of colonization and subsequent infection in liver transplant recipients at high risk for DRE bacteremia.

Molecular characterization of antimicrobial resistance and virulence factors of Enterococcus faecalis from ducks at slaughterhouses

This study investigated the prevalence of antimicrobial resistant Enterococcus faecalis (E. faecalis) from ducks at slaughterhouses, analyzed antimicrobial resistance genes and virulence-associated genes of the isolates. Multilocus sequence typing (MLST) was performed to characterize their molecular characteristics. A total of 227 E. faecalis isolates (67.8%) were obtained from cecum (n = 114), cloaca (n = 50), skin (n = 59), and rinsed water (n = 4). These E. faecalis exhibited high level of resistance against tetracycline (95.6%), doxycycline (94.3%), linezolid (75.8%), erythromycin (72.2%), followed by norfloxacin (56.8%), vancomycin (38.3%), penicillin (36.1%), teicoplanin (30.8%). Lower level of resistance was found to high-level streptomycin (19.8%), imipenem (15.9%) and high-level gentamicin (5.7%). The vast majority of isolates (90.3%) were multidrug resistant (MDR). Moreover, the commonly observed resistance genes were optrA (90.7%) and ermB (90.3%), followed by aph(3’)-Ⅲ (86.8%), tetM (84.6%), acc(6’)-aph(2) (77.5%), blaZ (76.7%) and aac(6’)-Ie-aph(2”)-Ia (75.8%). The less frequently observed genes were vanC (19.8%), blaTEM (4.8%), vanM (2.6%), and vanA (0.4%). None of the strains carried aph(2”)-Ic and vanB genes. Furthermore, a high prevalence of ten virulence determinants was identified, and efaA (99.1%) was predominant, followed by eep (97.4%), srtA (96.9%), asa1 (95.6%), fsrB (92.1%), sprE (89.9%), aggA (63.9%), gelE (56.4%), esp (33.9%), and cylL (15.4%). Eleven isolates (4.9%) co-carried all of the tested virulence-associated genes. MLST analysis demonstrated that, E. faecalis isolates consisted of 12 known STs and 5 new STs, among which 6 of the identified STs were associated with nosocomial infection. Our data indicated that retail ducks serve as an important source of MDR E. faecalis with high pathogenicity potential, and suggested that transmission to humans could not be excluded.

Perfil epidemiológico de la infección por Enterococcus SPP en un hospital regional

Introducción: los enterococos son responsables de múltiples infecciones y por su creciente patrón de resistencia se ha vuelto de interés en el país y en el mundo. Objetivo: caracterizar las infecciones por Enterococcus spp. Metodología: estudio descriptivo, retrospectivo observacional transversal desde enero 2015 hasta enero 2018 en un hospital regional. Resultados: la prevalencia de las infecciones por Enterococcus spp. fue de 0,154%. El E. faecalis fue el más aislado, seguido del E. faecium. La resistencia a ampicilina fue de 19% y a vancomicina de 10%; 32% de los pacientes tuvieron terapia empírica con vancomicina y 22% con piperacilina tazobactam, la mediana de antibioticoterapia fue de 10 días. Discusión: el interés por los Enterococcus spp. se ha incrementado debido a que representan una carga importante en las infecciones asociadas con la atención en salud (IAAS). La mayoría se dan en hombres con una edad mediana de 40 a 60 años, hospitalizados en UCI, con infecciones urinarias y comorbilidades como inmunosupresión y cirugías previas. Conclusión: como ha venido reportándose aumento en las tasas de resistencia a vancomicina y ampicilina, se recomienda el uso responsable de la terapia antibiótica, con la finalidad de erradicar en forma eficaz al patógeno y prevenir nuevas resistencias.

The Impact of Discontinuing Contact Precautions and Enforcement of Basic Hygiene Measures on Nosocomial Vancomycin-Resistant Enterococcus faecium Transmission

OBJECTIVES

Vancomycin-resistant Enterococcus faecium (VREfm) has emerged as a pathogen of major public health concern. Although definitive evidence is lacking, contact precautions have been a crucial element in infection prevention and control (IPC) strategies designed to limit nosocomial VRE transmissions. This study investigates the effect of discontinuing contact precautions while enforcing basic hygiene measures, including hand hygiene, environmental cleaning, and antiseptic body washing, for VRE patients at ICUs on prevention of nosocomial VRE transmission causing bacteraemia.

METHODS

Contact precaution was discontinued in January 2018. A total of 96 VREfm isolates from 61 ICU patients with VREfm bacteraemia and/or colonization from 8 ICUs in 2016 and 2019 in a tertiary care hospital were characterized by whole genome sequenicng. VRE transmission was investigated using patient movement data and admission screening for reliable identification of nosocomial acquisition.

RESULTS

Discontinuation of contact precautions did not increase VREfm transmission events (8 in 2016 vs 1 in 2019). While the rate of endogenous VREfm was similar in both years (38% vs 31%), the number of non-colonized patients prior to VREfm bacteraemia was 16 (16/29; 55%) in 2019, which was significantly higher than in 2016 (8/32; 25%). The mean incidence density for VREfm bacteraemia was similar for both years; 0.26 versus 0.31 per 1000 patient days in 2016 and 2019, respectively.

CONCLUSION

Our data suggest that discontinuation of contact precaution, while enforcing the basic hygiene measures did not lead to an increase of nosocomial bloodstream infection rates due to transmissions of VREfm in hyperendemic ICU settings.

Real-Time PCR Assay for Rapid and Simultaneous Detection of vanA and vanB Genes in Clinical Strains

Here, we develop a robust and sensitive real-time PCR assay which allows the simultaneous detection of vanA and vanB genes using common primers. The system was designed using the Primer3 online software. The specificity of primers and probes was first checked by in silico PCR and by BlastN analysis. The genomic DNA of 255 bacterial isolates, including Enterococcus spp., Gram-negative, and Gram-positive strains, as well as a collection of 50 stool and 50 rectal swab samples, were tested to evaluate the specificity of the new real-time PCR (RT-PCR) system. The results of the designed RT-PCR were 100% specific and 100% positive on tested vancomycin resistant isolates harboring either the vanA or vanB gene. RT-PCR assays were negative for all other bacterial species tested including vancomycin-sensitive Enterococci and Enterococcus strains harboring vanC genes. The limit of detection of vanA and vanB genes by RT-PCR assay was 47 CFU/mL and 32 CFU/mL, respectively. The rapid and accurate detection of vancomycin-resistant Enterococci is the cornerstone for minimizing the risk of nosocomial transmissions and outbreaks. We believe that this assay will strengthen routine diagnostics and surveillance programs.

Enterococci from Raw-Milk Cheeses: Current Knowledge on Safety, Technological, and Probiotic Concerns

The present study is focused on the safety, technological characteristics, and probiotic evaluation of Enterococcus species from different artisanal raw milk dairy products, mainly cheeses with ripening. Apart from proteolytic and lipolytic activities, most enterococci show the ability to metabolize citrate and convert it to various aromatic compounds. Long-ripened cheeses therefore have a specific flavor that makes them different from cheeses produced from thermally treated milk with commercial starter cultures. In addition, enterococci are producers of bacteriocins effective against spoilage and pathogenic bacteria, so they can be used as food preservatives. However, the use of enterococci in the dairy industry should be approached with caution. Although originating from food, enterococci strains may carry various virulence factors and antibiotic-resistance genes and can have many adverse effects on human health. Still, despite their controversial status, the use of enterococci in the food industry is not strictly regulated since the existence of these so-called desirable and undesirable traits in enterococci is a strain-dependent characteristic. To be specific, the results of many studies showed that there are some enterococci strains that are safe for use as starter cultures or as probiotics since they do not carry virulence factors and antibiotic-resistance genes. These strains even exhibit strong health-promoting effects such as stimulation of the immune response, anti-inflammatory activity, hypocholesterolemic action, and usefulness in prevention/treatment of some diseases.

Draft genome sequence of Staphylococcus agnetis 4244, a strain with gene clusters encoding distinct post-translationally modified antimicrobial peptides

OBJECTIVES

Here we report the draft genome sequence of Staphylococcus agnetis 4244, a strain involved in bovine mastitis, and its ability to inhibit different species of antibiotic-resistant Gram-positive bacteria owing to bacteriocin production.

METHODS

An Illumina MiSeq platform was used for genome sequencing. De novo genome assembly was done using the A5-miseq pipeline. Genome annotation was performed by the RAST server, and mining of bacteriocinogenic gene clusters was done using the BAGEL4 and antiSMASH v.5.0 platforms. Investigation of the spectrum of activity of S. agnetis 4244 was performed on BHI agar by deferred antagonism assay.

RESULTS

The total scaffold size was determined to be 2 511 708 bp featuring a G+C content of 35.6%. The genome contains 2431 protein-coding sequences and 80 RNA sequences. Genome analyses revealed three prophage sequences inserted in the genome as well as several genes involved in drug resistance and two bacteriocin gene clusters (encoding a thiopeptide and a sactipeptide) encoded on the bacterial chromosome. Staphylococcus agnetis 4244 was able to inhibit all 44 strains of antibiotic-resistant Gram-positive bacteria tested in this study, including vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA) and other antibiotic-resistant staphylococcal strains.

CONCLUSION

This study emphasises the potential biotechnological application of this strain for production of bacteriocins that could be used in the food industry as biopreservatives and/or in medicine as alternative therapeutic options against VRE, MRSA, vancomycin-intermediate S. aureus and other antibiotic-resistant Gram-positive bacteria, including biofilm-forming isolates. It also provides some genetic features of the draft genome of S. agnetis 4244.

First Report of the Plasmid-mediated fosB Gene in Enterococcus faecalis from Pigs

Plasmid-mediated fosfomycin determinants is a global public health concern due to the increasing dissemination of fosfomycin resistance and limited clinical treatment options. Information about the fosfomycin resistant and molecular genetic among Enterococcus spp. is still lacking. In this study, we found the first plasmid-medieted fosB in Enterococcus faecalis from pigs, and all the fosfomycin resistant Enterococcus spp. (FRE) isolates were multi-drug resistant. S1-PFGE, Southern blot and conjugation experiments indicated that the fosB gene located on ~54.7 kb transferable plasmids_. Relative competition assay confirmed that the fosB-carrying plasmid impaired fitness in recipient E. faecalis JH2-2. Illumina and the MinION sequencing data revealed that both E. faecalis ES-1 and ES-2 isolates belonged to novel ST (ST964), and had 71 SNPs difference. WGS showed that the genetic environments of fosB were diverse among different species, and the linezolid resistance gene optrA was found in the fosB-carrying strains. To summarize, for the first time, we reported plasmid-mediated fosB in E. faecalis from pigs. And, the co-occurrence of fosB and optrA pose a serious threat to public health.

Phloretin potentiates polymyxin E activity against gram-negative bacteria

AIMS

The spread of plasmid-mediated polymyxin resistance has jeopardized the use of polymyxin, the last defender that combats infections caused by multidrug-resistant (MDR) gram-negative pathogens.

MAIN METHODS

In this study, phloretin, as a monomeric compound extracted from natural plants, showed a good synergistic effect with polymyxin E against gram-negative bacteria, as evaluated by minimal inhibit concentration (MIC) assay and a series of assays, including growth curve, time-killing, and Western blot assays. A model of mice infected by Salmonella sp. stain HYM2 was established to further identify the synergistic effect of phloretin with polymyxin E.

KEY FINDINGS

The results suggested that phloretin had the potential ability to recover the antibacterial sensitivity of polymyxin E from 64 μg/mL to no more than 2 μg/mL in E. coli ZJ478 or in Salmonella sp. stain HYM2 with a 32-fold decrease. A series of strains, including mcr-1-positive and mcr-1-negative strains, were treated with a combination of phloretin and polymyxin E, and the fractional inhibitory concentration (FIC) values were all found to be below 0.5. However, the combination of phloretin and polymyxin E did not lead to bacterial resistance. In vivo, the survival rate of infected mice reached nearly 80% with the combination treatment, and the cecal colony value also decreased significantly.

SIGNIFICANCE

All the above results indicated that phloretin is a potential polymyxin potentiator to combat gram-negative stains.

Optimization of Linezolid Dosing Regimens for Treatment of Vancomycin-Resistant Enterococci Infection

BACKGROUND

Linezolid, an oxazolidinone antibiotic, is recommended for vancomycin-resistant enterococci (VRE). However, 100% free-drug concentration above the minimum inhibitory concentration (fT>MIC) and an area under the curve of free drug to MIC ratio (fAUC24/MIC) >100 were associated with favorable clinical outcome with less emerging resistance. A plasma trough concentration (C_trough) of linezolid ≥9 μg/mL was also related to hematologic toxicity. Thus, linezolid dose optimization is needed for VRE treatment. The study aimed to determine the in vitro linezolid activity against clinical VRE isolates and linezolid dosing regimens in critically ill patients who met the target pharmacokinetics/pharmacodynamics (PK/PD) for VRE treatment.

MATERIALS AND METHODS

Enterococcal isolates from enterococcal-infected patients were obtained between 2014 and 2018 at Phramongkutklao Hospital. We used Monte Carlo simulation to calculate the probability of target attainment, and the cumulative fraction of response (CFR) of the free area under the curve to MIC ratio (fAUIC₂₄) was used to calculate the fAUC24/MIC 80 - 100 and fT/MIC >85 - 100% of the interval time of administration for clinical response and microbiological eradication as well as the C_trough ≥9 μg/mL for the probability of hematologic toxicity.

RESULTS

For linezolid MIC determination, the MIC median (MIC₅₀), MIC for 90% growth (MIC₉₀), and range for linezolid were 1.5 μg/mL, 2 μg/mL, and 0.72 - 2 μg/mL, respectively. A dosing regimen of 1,200 mg either once daily or as a divided dose every 12 h gave target attainments of fAUC24/MICs >80 and >100, which exceeded 90% for MICs ≤1 and ≤1 μg/mL, respectively, with a rate of hematologic toxicity <15%. If the expected fT>MICs were >85% and 100%, a 1,200-mg divided dose every 12 h could cover VRE isolates having linezolid MICs ≤1 μg/mL and ≤0.75 μg/mL. Even 600 mg every 8 h and 1,200 mg as a continuous infusion gave a higher target attainment of fAUC24/MIC and a fT>MIC and the target CFR, but those regimens gave C_trough ≥9 μg/mL rates of 40.7% and 99.6%.

CONCLUSION

The current dosing of 1,200 mg/day might be optimal treatment for infection by VRE isolates with documented MICs ≤1 μg/mL. For treatment of VRE with a MIC of 2 μg/mL or to achieve the target CFR, the use of linezolid with other antibiotic combinations might help achieve the PK/PD target, provide better clinical outcome, and prevent resistance.

Molecular epidemiology of vancomycin-resistant Enterococcus faecium clinical isolates in a tertiary care hospital in southern Thailand: a retrospective study

Objective

Vancomycin-resistant enterococci are nosocomial pathogens that are responsible for commonly causing healthcare-associated infections, and they exhibit increased resistance to many antimicrobials, particularly to vancomycin. The epidemiological data available on vancomycin-resistant enterococci (VRE) in Thailand are inadequate.

Methods

Using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR), this study investigated genes that encode antimicrobial resistance and genetic relatedness to further understand VRE prevalence. Ninety VRE isolates were collected between 2011 and 2019 from a tertiary care hospital in southern Thailand. Antimicrobial susceptibility was determined using the disk diffusion method and E-test methods. Multiplex PCR was performed to detect the van gene and virulence genes.

Results

The study showed a high prevalence of diverse multidrug-resistant VRE strains. The prevalence of VRE infection was the highest in 2014 (28 isolates, 39.4%). VRE were mostly found in the urogenital tract (26 isolates, 28.9%), followed by the digestive tract (20%), body fluid, i.e., pancreatic cyst fluid, peritoneal dialysis fluid, Jackson–Pratt (JP) drain (20%), and blood specimens (10%). Patients in medical and surgical wards had 71.1% multi-drug-resistant and 28.9% extensively drug-resistant (XDR) VRE strains, respectively. The most prevalent antibiotic resistance was to ampicillin (74.4%). Susceptibility to gentamicin and meropenem were similar (7% and 10%, respectively). Four isolates (4.4%) were resistant to colistin. Only vanA was detected among the strains. The virulence gene test showed that the detection rates of enterococcal surface protein (esp) and hyaluronidase (hyl) genes were 91.1% and 5.6%, respectively. According to ERIC-PCR analysis, 51 of 90 strains had clonality, with a similarity rate of 95%.

Conclusions

We conclude that there is a need to implement infection control practices and active surveillance. Molecular techniques can effectively detect antibiotic-resistant genes, which would allow monitoring to control VRE infection in hospitals.

Epidemiology and Outcomes of Vancomycin-Resistant Enterococcus Infections in the U.S. Military Health System

INTRODUCTION

Vancomycin-resistant enterococci (VRE) are classified by the Centers for Diseases Control and Prevention as a serious antibiotic resistance threat. Our study aims to characterize the epidemiology, associated conditions, and outcomes of VRE infections among hospitalized patients in the U.S. military health system (MHS).

MATERIALS AND METHODS

We performed a retrospective cohort study of patients with VRE infection using the MHS database. Cases included all patients admitted to a military treatment facility for ≥2 days from October 2008 to September 2015 with a clinical culture growing Enterococcus faecalis, Enterococcus faecium, or Enterococcus species (unspecified), reported as resistant to vancomycin. Co-morbid conditions and procedures associated with VRE infection were identified by multivariable conditional logistic regression. Patient case-mix adjusted outcomes including in-hospital mortality, length of stay, and hospitalization cost were evaluated by high-dimensional propensity score adjustment.

RESULTS

During the seven-year study period and among 1,161,335 hospitalized patients within the MHS, we identified 577 (0.05%) patients with VRE infection. A majority of VRE infections were urinary tract infections (57.7%), followed by bloodstream (24.7%), other site/device-related (12.9%), respiratory (2.9%), and wound infections (1.8%). Risk factors for VRE infection included invasive gastrointestinal, pulmonary, and urologic procedures, indwelling devices, and exposure to 4th generation cephalosporins, but not to glycopeptides. Patients hospitalized with VRE infection had significantly higher hospitalization costs (attributable difference [AD] $135,534, P<0.001), prolonged hospital stays (AD 20.44 days, P<0.001, and higher in-hospital mortality (case-mix adjusted odds ratio 5.77; 95% confidence interval 4.59-7.25).

CONCLUSIONS

VRE infections carry a considerable burden for hospitalized patients given their impact on length of stay, hospitalization costs, and in-hospital mortality. Active surveillance and infection control efforts should target those identified as high-risk for VRE infection. Antimicrobial stewardship programs should focus on limiting exposure to 4th generation cephalosporins.

The antiseptic Miramistin: a review of its comparative in vitro and clinical activity

Miramistin is a topical antiseptic with broad antimicrobial action, including activity against biofilms and a clinical profile showing good tolerability. Miramistin was developed within a framework of the Soviet Union Cold War Space Program. It is available for clinical use in several prior Soviet bloc countries, but barely known outside of these countries and there is almost no mention of miramistin in the English literature. However, considering emerging antimicrobial resistance, the significant potential of miramistin justifies its re-evaluation for use in other geographical areas and conditions. The review consists of two parts: (i) a review of the existing literature on miramistin in English, Russian and Ukrainian languages; (ii) a summary of most commonly used antiseptics as comparators of miramistin. The oral LD50 was 1200 mg/kg, 1000 mg/kg and 100 g/L in rats, mice and fish, respectively. Based on the results of the review, we suggest possible applications of miramistin and potential benefits over currently used agents. Miramistin offers a novel, low toxicity antiseptic with many potential clinical uses that need better study which could address some of the negative impact of antimicrobial, antiseptic and disinfectant resistance.

Does Vancomycin Resistance Increase Mortality? Clinical Outcomes and Predictive Factors for Mortality in Patients with Enterococcus faecium Infections

The prevalence of enterococcal infection, especially E. faecium, is increasing, and the issue of the impact of vancomycin resistance on clinical outcomes is controversial. This study aimed to investigate the clinical outcomes of infection caused by E. faecium and determine the risk factors associated with mortality. This retrospective study was performed at the Phramongkutklao Hospital during the period from 2014 to 2018. One hundred and forty-five patients with E. faecium infections were enrolled. The 30-day and 90-day mortality rates of patients infected with vancomycin resistant (VR)-E. faecium vs. vancomycin susceptible (VS)-E. faecium were 57.7% vs. 38.7% and 69.2% vs. 47.1%, respectively. The median length of hospitalization was significantly longer in patients with VR-E. faecium infection. In logistic regression analysis, VR-E. faecium, Sequential Organ Failure Assessment (SOFA) scores, and bone and joint infections were significant risk factors associated with both 30-day and 90-day mortality. Moreover, Cox proportional hazards model showed that VR-E. faecium infection (HR 1.91; 95%CI 1.09–3.37), SOFA scores of 6–9 points (HR 2.69; 95%CI 1.15–6.29), SOFA scores ≥ 10 points (HR 3.71; 95%CI 1.70–8.13), and bone and joint infections (HR 0.08; 95%CI 0.01–0.62) were significant risk factors for mortality. In conclusion, the present study confirmed the impact of VR-E. faecium infection on mortality and hospitalization duration. Thus, the appropriate antibiotic regimen for VR-E. faecium infection, especially for severely ill patients, is an effective strategy for improving treatment outcomes.

Comprehensive, multisystem, mechanical decolonization of Vancomycin-Resistant Enterococcus and Carbapenem-Resistant Enterobacteriacease without the use of antibiotics

Among multidrug-resistant organisms (MDROs), Vancomycin-resistant Enterococcus (VRE), and Carbapenem-resistant Enterobacteriaceae (CRE) have become major nosocomial pathogens that are endemic worldwide. If VRE/CRE are present as colonizing organisms but do not act as pathogens, these organisms do not cause symptoms and do not require antibiotic use. However, once gastrointestinal colonization with VRE/CRE occurs, it can persist for long periods and serve as a reservoir for transmission to other patients. Therefore, a breakthrough strategy to control the spread of MDRO colonization is needed. We herein introduce decolonization method, which is a comprehensive, multisystem, consecutive mechanical MDRO decolonization protocol that does not utilize antibiotics. Our protocol included: (1).. Mechanical evacuation using a glycerin enema, (2).. Replacement of the normal gut flora using daily lactobacillus ingestion, (3).. Skin hygiene cleansing using chlorhexidine, and (4).. Environmental cleansing by changing the bed sheets and clothing every day. These steps were repeated consecutively until the patient was released from quarantine. We conducted VRE/CRE tests every week. Because our protocol was a comprehensive and multisystem decolonization protocol, the cooperation of patients and/or caregivers was essential, and family support was important for patient care. Patients were divided into VRE and CRE groups and were subdivided into success and failure groups according to decolonization status. Thirty-two patients with VRE or CRE colonization were enrolled, and our protocol was performed. A total of 20 patients (62.5%) were successfully decolonized after repeated protocols. Univariate analysis revealed that patients with younger age, higher body mass index (BMI), shorter period of MDRO isolation without trial, and higher functional status showed significantly enhanced success rates with our decolonization protocol. This study presents the decolonization effects of a comprehensive, multisystem, mechanical decolonization protocol for VRE and CRE. Most importantly, our decolonization protocol does not use antibiotics and is thus not harmful. These results suggest an active decolonization trial to be performed as early as possible in patients with VRE or CRE colonization. This simple, easy-to-apply protocol can be used as 1 of the basic treatment options for MDROs infection or colonization, regardless of whether it requires antibiotic treatment.

Whole-genome sequencing analysis reveals the spread of a vanB-carrying transposon among different vancomycin-resistant Enterococcus faecium clinical isolates in a non-endemic setting

BACKGROUND

Vancomycin-resistant enterococci (VRE), particularly Enterococcus faecium (VREfm), can cause serious nosocomial infections, and have been responsible for healthcare-associated outbreaks. Spreading of VREfm can occur both clonally and by the dissemination of mobile genetic elements.

AIM

To report prospective analysis of whole-genome sequencing (WGS) data, including both core-genome multi-locus sequence typing (cgMLST) and transposon analysis, during a vanB VREfm outbreak.

METHODS

Screening for vanB-positive VREfm isolates was performed by real-time polymerase chain reaction (PCR) on an overnight enriched broth and, if positive, subculture was performed. vanB-positive VREfm isolates underwent WGS. Generated data were used for molecular typing that was performed by cgMLST using SeqSphere. For transposon characterization, sequence data were mapped against the reference sequence of transposon Tn1549 using CLC Genomics Workbench, or de-novo assemblies were used for BLASTN comparisons.

RESULTS

In total, 1358 real-time PCRs were performed. Two hundred and fifty-one specimens from 207 patients tested positive on PCR for vanB, of which 13 specimens obtained from six patients were identified as vanB VREfm positive on culture. These six patients harboured seven unique isolates belonging to four cluster types: CT118 (N=2), CT2483 (N=3), CT2500 (N=1) and CT2501 (N=1). Transposon analysis revealed the presence of an identical vanB-carrying transposon in the isolates cultured from all six patients that could be linked based on epidemiological data.

CONCLUSION

A vanB VREfm outbreak occurred in the study hospital, including six patients with isolates belonging to four cluster types. In-depth transposon analysis revealed that dissemination of transposon Tn1549 rather than clonal spread was the cause of the outbreak.

Methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci co-colonization in patients: A meta-analysis

BACKGROUND

Co-colonization of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) may result in the transfer of drug-resistant genes. The aim of this meta-analysis was to estimate the pooled co-colonization prevalence of MRSA and VRE.

METHODS

We searched PubMed, Embase, and Web of Science databases. The co-colonization prevalence of MRSA and VRE was assessed by calculating the proportion and 95% confidence intervals (CI). The random-effects model was used to calculate the pooled prevalence.

RESULTS

Eleven eligible studies were included in this meta-analysis. The pooled co-colonization prevalence of MRSA and VRE in patients was 7% (95% CI, 5.0%-9.0%). The results of regression analysis showed that co-colonization prevalence of MRSA and VRE was related to study design, setting, screening sites, and detection methods. We found that male patients (odds ratio [OR], 1.58; 95% CI, 1.09-2.28), patients with comorbid conditions such as diabetes mellitus (OR, 1.37; 95% CI, 1.05-1.78), chronic obstructive pulmonary disease (OR, 1.88; 95% CI, 1.27-2.79), and use of indwelling devices (OR, 4.08; 95% CI, 2.21-7.53) were risk factors for co-colonization by MRSA and VRE.

CONCLUSIONS

The co-colonization prevalence of MRSA and VRE in the patients was common. Appropriate measures should be adopted to limit the horizontal transmission of MRSA and VRE to minimize the future potential for co-colonization and the transfer of resistance genes among these pathogens.

Enterococci, from Harmless Bacteria to a Pathogen

Enterococci are gastrointestinal commensals whose hardiness allowed them to colonize very diverse environments, including soils, water, food, and feed. This ability to overcome adverse conditions makes enterococci problematic once they colonize hospital niches. Together with the malleability of their genomes, the capacity to acquire and disseminate determinants of antibiotic resistance has contributed to converting what was once just another opportunistic pathogen into a first-class clinical problem. This review discusses the dimension of the emergence of enterococcal resistance to key antimicrobial agents, the dissemination of this resistance, and its significance in terms of public health, with the aim of raising awareness of the need to devise and implement surveillance programs and more effective antibiotic stewardship.

Self-Assembled Supramolecular Hybrid Hydrogel Beads Loaded with Silver Nanoparticles for Antimicrobial Applications

This Full Paper reports the formation of silver (Ag) NPs within spatially resolved two-component hydrogel beads, which combine a low-molecular-weight gelator (LMWG) DBS-CONHNH2 and a polymer gelator (PG) calcium alginate. The AgNPs are formed through in situ reduction of AgI , with the resulting nanoparticle-loaded gels being characterised in detail. The antibacterial activity of the nanocomposite gel beads was tested against two drug-resistant bacterial strains, often associated with hospital-acquired infections: vancomycin-resistant Enterococcus faecium (VRE) and Pseudomonas aeruginosa (PA14), and the AgNP-loaded gels showed good antimicrobial properties against both types of bacteria. It is suggested that the gel bead format of these AgNP-loaded hybrid hydrogels makes them promising versatile materials for potential applications in orthopaedics or wound healing.

Characterization of clinical enterococci isolates, focusing on the vancomycin-resistant enterococci in a tertiary hospital in China: based on the data from 2013 to 2018

Background

Vancomycin-resistant Enterococcus spp. (VRE) have spread all over the world. The present study aims to investigate the species distribution, specimen type and susceptibilities of Enterococcal species collected from Nanjing Drum Tower Hospital from 2013 to 2018. Additionally, distribution of VRE and prevalence of van gene among VRE isolates were also analyzed.

Methods

The susceptibilities of 3913 Enterococcus isolates were retrospectively investigated. Among these strains, 60 VRE strains were further anazlyed in this study. The minimum inhibitory concentrations (MICs) of the VRE strains towards vancomycin, teicoplanin and linezolid were determined by E-test. Polymerase chain reaction (PCR) and DNA sequencing were used to investigate the prevalence of van genes among VRE. Furthermore, the sequence types (STs) of VRE strains were explored by multi-locus sequence typing (MLST).

Results

Among the 3913 enterococci isolates, Enterococcus faecalis (n = 1870, 47.8%) and Enterococcus faecium (1738, 44.4%) were the main isolates. These Enterococcus strains were mainly isolated from urine (n = 1673, 42.8%), followed by secretions (n = 583, 14.9%) and ascites (n = 554, 14.2%). VRE displayed a decreasing trend year by year. Molecular analysis revealed that 49 out of 60 VRE isolates carried vanA gene, 10 carried vanM, and 1 carried both vanA and vanM genes. Sixteen distinct STs were identified among the 58 VREM, with ST78 (n = 16), ST192 (n = 8) and ST570 (n = 7) being the most dominant ones.

Conclusions

E. faecalis and E. faecium were the major enterococci strains which are the main pathogens of urinary traction infections; vanA and vanM were the main determinants conferring resistance to vancomycin; ST78, ST192 and ST570 were the leading STs of VREM which displayed a decreasing trend of prevalence year by year.

Next-Generation Sequencing and MALDI Mass Spectrometry in the Study of Multiresistant Processed Meat Vancomycin-Resistant Enterococci (VRE)

Vancomycin-resistant enterococci (VRE), due to their intrinsic resistance to various commonly used antibiotics and their malleable genome, make the treatment of infections caused by these bacteria less effective. The aims of this work were to characterize isolates of Enterococcus spp. that originated from processed meat, through phenotypic and genotypic techniques, as well as to detect putative antibiotic resistance biomarkers. The 19 VRE identified had high resistance to teicoplanin (89%), tetracycline (94%), and erythromycin (84%) and a low resistance to kanamycin (11%), gentamicin (11%), and streptomycin (5%). Based on a Next-Generation Sequencing NGS technique, most isolates were vanA-positive. The most prevalent resistance genes detected were erm(B) and aac(6')-Ii, conferring resistance to the classes of macrolides and aminoglycosides, respectively. MALDI-TOF mass spectrometry (MS) analysis detected an exclusive peak of the Enterococcus genus at m/z (mass-to-charge-ratio) 4428 ± 3, and a peak at m/z 6048 ± 1 allowed us to distinguish Enterococcus faecium from the other species. Several statistically significant protein masses associated with resistance were detected, such as peaks at m/z 6358.27 and m/z 13237.3 in ciprofloxacin resistance isolates. These results reinforce the relevance of the combined and complementary NGS and MALDI-TOF MS techniques for bacterial characterization.

Electrochemical aptasensors based on the gold nanostructures

Electrochemical aptasensors as novel diagnostic tools have attracted sufficient research interest in biomedical sciences. In this review, recent leading trends about gold (Au) nanostructures based electrochemical aptasensors have been collected, reviewed, and compared. Here, the considered electrochemical aptasensors were categorized based on the analytes and diagnostic techniques. Pharmaceutical analytes and biomolecules were reviewed in a separate section consisting of a variety of antibiotics, analgesics, and other biomolecules. Various aptasensors have also measured toxins, ions, and hazardous chemicals, and the findings of them have also been reviewed. Many aptasensors have been designed to detect different disease biomarkers that will play an essential role in the future of early diagnosis of diseases. Pathogen microorganisms have been considered as the analyte in several designed electrochemical aptasensors in recent researches, and their results have been reviewed and discussed as another section. Important aspects considered in the review of the mentioned aptasensors were the type of analyte, features of the aptamer as the biorecognition element, type of Au nanostructures, diagnostic technique, diagnostic mechanism, detection range and the limit of detection (LOD). In the last section, an in-depth analysis has been provided based on the crucial features of all included aptasensors.

Antibiotic Resistance and Molecular Epidemiology of Vancomycin-Resistant Enterococci in a Tertiary Care Hospital in Turkey

PURPOSE

Vancomycin-resistant enterococci (VRE) have become a global health threat in the last two decades. In this study, we aimed to determine antibiotic resistance using phenotypic and genotypic methods in VRE strains obtained from inpatients and to investigate clonal relatedness among strains.

METHODS

Identification and antibiotic susceptibility of 47 VRE strains obtained from inpatients at Karabuk University Hospital from 2014 to 2015 were determined using the BD Phoenix™ automated microbiology system. Vancomycin resistance genes (Van A and B) were detected by polymerase chain reaction. Clonal relatedness among the strains was evaluated by pulsed-field gel electrophoresis (PFGE).

RESULTS

All 47 VRE strains obtained from rectal (n=35), blood (n=7), and urine (n=5) samples were confirmed as Enterococcus faecium; they were resistant to ampicillin, gentamicin, vancomycin, and teicoplanin. One E. faecium isolate was intermediately resistant to linezolid. No strain was resistant to quinupristin-dalfopristin or daptomycin. Only vanA was detected among strains. According to the PFGE results, 31 of 47 strains were clonally related with a clustering rate of 66%. No common clone was detected.

CONCLUSION

VRE infections are associated with high mortality, morbidity, and healthcare expenditures. Increasing resistance to last-line drugs, such as linezolid and daptomycin, among VRE strains is a great concern. Therefore, comprehensive measures should be performed to reduce VRE colonization. Although there was no common clone VRE outbreak, polyclonal spread was observed in our hospital. The high clustering rate indicated cross-contamination. Thus, a more effective infection control program should be implemented.

Epidemiology of Vancomycin-Resistant Enterococcus faecium and Enterococcus faecalis Colonization in Nursing Facilities

BACKGROUND

Vancomycin-resistant Enterococcus faecium and Enterococcus faecalis frequently colonize nursing facility (NF) residents, creating opportunities for vancomycin-resistant Enterococcus (VRE) transmission and dissemination of mobile genetic elements conferring antimicrobial resistance. Most VRE studies do not speciate; our study addresses this lack and compares the epidemiology of E faecium and E faecalis.

METHODS

We enrolled 651 newly admitted patients from 6 different NFs and collected swabs from several body sites at enrollment, 14 days, 30 days, and monthly thereafter for up to 6 months. The VRE were speciated using a duplex polymerase chain reaction. We used multinomial logistic regression models to compare risk factors associated with colonization of E faecium and E faecalis.

RESULTS

Overall, 40.7% were colonized with E faecium, E faecalis, or both. At enrollment, more participants were colonized with E faecium (17.8%) than E faecalis (8.4%); 3.2% carried both species. Enterococcus faecium was carried twice as long as E faecalis (69 days and 32 days, respectively), but incidence rates were similar (E faecium, 3.9/1000 person-days vs E faecalis, 4.1/1000 person-days). Length of stay did not differ by species among incident cases. Residents who used antibiotics within the past 30 days had a greater incidence of both E faecium (odds ratio [OR] = 2.89; 95% confidence interval [CI], 1.82-4.60) and E faecalis (OR = 1.80; 95% CI, 1.16-2.80); device use was most strongly associated with the incidence of E faecium colonization (OR = 2.01; 95% CI, 1.15-3.50).

CONCLUSIONS

Recent increases in vancomycin-resistant E faecium prevalence may reflect increased device use and longer duration of carriage.

Pharmacodynamics Of Linezolid-Plus-Fosfomycin Against Vancomycin-Susceptible And -Resistant Enterococci In Vitro And In Vivo Of A Galleria mellonella Larval Infection Model

Objectives

To explore the in vitro and in vivo antibacterial activity of linezolid/fosfomycin combination against vancomycin-susceptible and -resistant enterococci (VSE and VRE), and provide a theoretical basis for the treatment of VRE.

Methods

The checkerboard method and time-kill curve study were used to evaluate the efficacy of linezolid combined with fosfomycin against VSE and VRE. The transmission electron microscopy (TEM) was employed to observe the cell morphology of bacteria treated with each drug alone or in combination, which further elucidate the mechanism of action of antibiotic combination therapy. The Galleria mellonella infection model was constructed to demonstrate the in vivo efficacy of linezolid plus fosfomycin for VSE and VRE infection.

Results

The fractional inhibitory concentration index (FICI) values of all strains suggested that linezolid showed synergy or additivity in combination with fosfomycin against five of the six strains. Time-kill experiments demonstrated that the combination of linezolid-fosfomycin at 1×MIC or 2×MIC led to higher degree of bacterial killing without regrowth for all isolates tested than each monotherapy. TEM images showed that the combination treatment damaged the bacterial cell morphology more obviously than each drug alone. In the Galleria mellonella infection model, the enhanced survival rate of the combination treatment compared with linezolid monotherapy (P<0.05) was revealed.

Conclusion

Our data manifested that the combination of linezolid and fosfomycin was a potential therapeutic regimen for VRE infection. The combination displayed excellent bacterial killing and inhibited amplification of fosfomycin-resistant subpopulations.

Urinary tract infection and subclinical bacteriuria in cats: A clinical update

PRACTICAL RELEVANCE

Urinary tract infection (UTI) is an important cause of feline lower urinary tract disease (FLUTD), particularly in female cats older than 10 years of age. In addition to cats with typical clinical signs of FLUTD or upper UTI, many cats have subclinical bacteriuria, but the clinical relevance of this is currently uncertain. UTIs are one of the most important indications for antimicrobial use in veterinary medicine and contribute to the development of antimicrobial resistance. Adherence to treatment guidelines and confinement to a few first-line antimicrobial agents is imperative to avoid further deterioration of the antimicrobial resistance situation. The decision to treat with antimicrobials should be based on the presence of clinical signs, and/or concurrent diseases, and the results of urine culture and susceptibility testing.

CLINICAL CHALLENGES

Distinguishing between cats with bacterial cystitis, and those with idiopathic cystitis and concurrent clinical or subclinical bacteriuria, is challenging, as clinical signs and urinalysis results may be identical. Optimal treatment of subclinical bacteriuria requires clarification as there is currently no evidence that demonstrates a beneficial effect of routine treatment. Management of recurrent UTIs remains a challenge as evidence for most alternatives used for prevention in cats is mainly anecdotal, and no preventive treatment modality is currently recommended.

EVIDENCE BASE

This review draws on an extensive literature base in veterinary and human medicine, including the recently updated guidelines of the International Society for Companion Animal Infectious Diseases for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Where published evidence is lacking, the authors describe their own approach; notably, for the bacteriuric cat with chronic kidney disease.

Active surveillance at the time of hospital admission for multidrug-resistant microorganisms among patients who had recently been hospitalized at health care facilities

BACKGROUND

This study aimed to investigate the epidemiology of multidrug-resistant microorganism (MDRO) carriage at hospital admission and to identify risk factors for MDRO influx into hospital settings.

METHODS

This cohort study was conducted at a 1,051-bed university-affiliated hospital in the Republic of Korea between July 1 and December 31, 2017. Active surveillance for MDRO carriage was performed within 48 hours of hospitalization in all adult patients who had prior hospitalization within the preceding 3 months.

RESULTS

During the study, 575 patients were admitted with a hospitalization history within 3 months. Active surveillance at hospital admission was performed in 192 eligible patients. Thirty-three (17.2%) patients with MDRO carriage were identified from active surveillance. In the multivariate logistic regression analysis, prior exposure to antibiotics within 90 days, hospitalization for ≥60 days before admission, cognitive dysfunction, percutaneous drainage, and underlying pulmonary diseases were identified as independent risk factors for MDRO influx.

CONCLUSIONS

Our findings suggest a significant prevalence of MDRO acquisition at acute care hospital admission in patients who had been recently hospitalized. To control the spread of MDRO, collaborations among health care institutions and targeted screening at hospital admission according to patient risk factors are warranted.