Risk Factors for Long-Term Vancomycin-Resistant Enterococci Persistence-A Prospective Longitudinal Study

Active surveillance of vancomycin-resistant Enterococcus faecium after its outbreak at patient admission

Vancomycin-resistant Enterococcus faecium (VRE) causes high mortality and has been increasingly detected worldwide in recent years; however, its screening effectiveness at admission remains controversial. We aimed to evaluate the effectiveness of active surveillance culture (ASC) for VRE at admission following a nosocomial outbreak. A VRE outbreak occurred at Shizuoka General Hospital in 2022, and ASC for VRE was performed upon admission for high-risk cases after the outbreak between January 2023 and December 2023. ASC was conducted in 2941 patients at admission, with 13 of them testing positive (0.44 %). The highest cumulative incidence and odds ratios (ORs) of ASC positivity at admission were detected among patients with a VRE detection history (5/18, cumulative incidence: 27.78 %, OR: 140.14, p < 0.001). The second highest cumulative incidence and OR occurred in patients hospitalized within the past 3 months in VRE-endemic areas (5/85, cumulative incidence: 5.88 %, OR: 22.25, p < 0.001). Hospitalization at SGH within the past 3 months showed a low cumulative incidence and OR (1/2,034, cumulative incidence: 0.05 %, OR: 0.037, p = 0.002). Among patients with urinary catheters, three of 132 patients tested ASC-positive (cumulative incidence: 2.27 %, OR: 6.51, p = 0.05), and six out of 403 individuals requiring toilet assistance were ASC-positive (cumulative incidence: 1.49 %, OR: 5.46, p = 0.02). None of the ASC-positive patients had a history of nursing home admissions or diarrhea. Our findings suggest that following a VRE nosocomial outbreak, ASC at admission should be prioritized for patients with a history of VRE detection or recent hospitalization in VRE-endemic areas.

Duration of hospitalization increases the risk for long-term carriage of linezolid-resistant enterococci in critically ill patients

BACKGROUND

Enterococci are gut commensal microorganisms, which can however cause life-threatening infections especially in patients suffering from intestinal barrier disorders. Treatment of these enterococcal infections is challenging due to a variety of intrinsic and acquired antibiotic resistances. In this context, linezolid is applied as last-resort antibiotic. Our study aimed at determining linezolid-resistant enterococci (LRE) long-term carriage (≥ 10 weeks), since this is a risk factor for the development of LRE infection.

METHODS

In a one-year cohort study, all patients on hemato-oncology, intensive and intermediate care units were screened for LRE. To determine the molecular epidemiology, all detected LRE isolates were subjected to whole genome sequencing-based typing to investigate whether in-host selection or pathogen transmission was causative for LRE occurrence. Clinical and demographic data were recorded to identify risk factors for LRE clearance and persistence.

RESULTS

Long-term LRE carriage was identified in 7 of 46 (15%) patients. Duration of hospitalization differed significantly between LRE persistence (mean: 110 days; range 28-225 days) and clearance group (mean: 53 days; range 5-213 days). LRE strains mostly exhibited a high genetic core genome diversity, indicating that transmission events played a minor role.

CONCLUSIONS

Our study shows that the duration of hospitalization increases the risk for long-term carriage of LRE. In contrast to other multi drug resistant bacteria, LRE carriage was rarely caused by transmission events. Thus, future infection prevention measures should focus on antimicrobial stewardship approaches next to classical hygiene strategies.

Epidemiology and Clinical Impact of Vancomycin-Resistant Enterococcus at King Abdulaziz University Hospital (2015-2022): Prevalence, Risk Factors, and Mortality

Background

Enterococcus faecalis and Enterococcus faecium are part of the human microbiota but pose significant risks in clinical settings due to increasing antimicrobial resistance. Vancomycin-resistant enterococci (VRE) are a growing concern, linked to high morbidity and mortality in hospitalized patients.

Aim

This study is the first comprehensive investigation of VRE prevalence and associated risk factors at King Abdulaziz University Hospital (KAUH) from 2015 to 2022.

Methods

Clinical samples were collected, and VRE isolates were identified using VRE Card GeneXpert, BioFire PCR, and the VITEK 2 system. Descriptive statistical analysis with Stata version 17 summarized patient characteristics, including demographics, comorbidities, hospital exposure, and laboratory findings. Categorical variables were reported as frequencies/percentages, while continuous variables were expressed as mean ± SD or median [IQR].

Results

Among 254 adult patients with VRE infections, the median age was 61 years. The most common comorbidities were diabetes, hypertension, and kidney disease. VRE infections peaked in 2021, with urine cultures being the most frequent source. Most patients had prior antibiotic exposure, particularly to vancomycin and carbapenems. Enterococcus faecium was the predominant species, with the VanA phenotype being most common. Alarmingly, 61.8% of VRE-infected patients died during the study period.

Conclusion

These findings underscore the critical need for enhanced infection control measures and antimicrobial stewardship to combat VRE and improve patient outcomes.

Bacteriocin production facilitates nosocomial emergence of vancomycin-resistant Enterococcus faecium

Gastrointestinal colonization by the nosocomial pathogen vancomycin-resistant Enterococcus faecium (VREfm) can lead to bloodstream infections with high mortality rates. Shifts in VREfm lineages found within healthcare settings occur, but reasons underlying these changes are not understood. Here we sequenced 710 VREfm clinical isolates collected between 2017 and 2022 from a large tertiary care centre. Genomic analyses revealed a polyclonal VREfm population, although 46% of isolates formed genetically related clusters, suggesting a high transmission rate. Comparing these data to a global collection of 15,631 publicly available VREfm genomes collected between 2002 and 2022 identified replacement of the sequence type (ST) 17 VREfm lineage by emergent ST80 and ST117 lineages at the local and global level. Comparative genomic and functional analyses revealed that emergent lineages encoded bacteriocin T8, which conferred a competitive advantage over bacteriocin T8-negative strains in vitro and upon colonization of the mouse gut. Bacteriocin T8 carriage was also strongly associated with strain emergence in the global genome collection. These data suggest that bacteriocin T8-mediated competition may have contributed to VREfm lineage replacement.

Bacteriocin production facilitates nosocomial emergence of vancomycin-resistant Enterococcus faecium

Vancomycin-resistant Enterococcus faecium (VREfm) is a prevalent healthcare-acquired pathogen. Gastrointestinal colonization can lead to difficult-to-treat bloodstream infections with high mortality rates. Prior studies have investigated VREfm population structure within healthcare centers. However, little is known about how and why hospital-adapted VREfm populations change over time. We sequenced 710 healthcare-associated VREfm clinical isolates from 2017-2022 from a large tertiary care center as part of the Enhanced Detection System for Healthcare-Associated Transmission (EDS-HAT) program. Although the VREfm population in our center was polyclonal, 46% of isolates formed genetically related clusters, suggesting a high transmission rate. We compared our collection to 15,631 publicly available VREfm genomes spanning 20 years. Our findings describe a drastic shift in lineage replacement within nosocomial VREfm populations at both the local and global level. Functional and genomic analysis revealed, antimicrobial peptide, bacteriocin T8 may be a driving feature of strain emergence and persistence in the hospital setting.

A simple solid media assay for detection of synergy between bacteriophages and antibiotics

The emergence of antibiotic-resistant bacteria (ARB) has necessitated the development of alternative therapies to deal with this global threat. Bacteriophages (viruses that target bacteria) that kill ARB are one such alternative. Although phages have been used clinically for decades with inconsistent results, a number of recent advances in phage selection, propagation, and purification have enabled a reevaluation of their utility in contemporary clinical medicine. In most phage therapy cases, phages are administered in combination with antibiotics to ensure that patients receive the standard-of-care treatment. Some phages may work cooperatively with antibiotics to eradicate ARB, as often determined using non-standardized broth assays. We sought to develop a solid media-based assay to assess cooperativity between antibiotics and phages to offer a standardized platform for such testing. We modeled the interactions that occur between antibiotics and phages on solid medium to measure additive, antagonistic, and synergistic interactions. We then tested the method using different bacterial isolates and identified a number of isolates where synergistic interactions were identified. These interactions were not dependent on the specific organism, phage family, or antibiotic used. A priori susceptibility to the antibiotic or the specific phage were not requirements to observe synergistic interactions. Our data also confirm the potential for the restoration of vancomycin to treat vancomycin-resistant Enterococcus (VRE) when used in combination with phages. Solid media assays for the detection of cooperative interactions between antibiotics and phages can be an accessible technique adopted by clinical laboratories to evaluate antibiotic and phage choices in phage therapy.IMPORTANCEBacteriophages have become an important alternative treatment for individuals with life-threatening antibiotic-resistant bacteria (ARB) infections. Because antibiotics represent the standard-of-care for treatment of ARB, antibiotics and phages often are delivered together without evidence that they work cooperatively. Testing for cooperativity can be difficult due to the equipment necessary and a lack of standardized means for performing the testing in liquid medium. We developed an assay using solid medium to identify interactions between antibiotics and phages for gram-positive and gram-negative bacteria. We modeled the interactions between antibiotics and phages on solid medium, and then tested multiple replicates of vancomycin-resistant Enterococcus (VRE) and Stenotrophomonas in the assay. For each organism, we identified synergy between different phage and antibiotic combinations. The development of this solid media assay for assessing synergy between phages and antibiotics will better inform the use of these combinations in the treatment of ARB infections.

Exploring the feasibility of bacteriocins EntK1 and EntEJ97s in treatment of systemic vancomycin resistant enterococci infections in mice

AIMS

Enterocins K1 and EJ97 have specific antimicrobial activity against Enterococcus faecium and Enterococcus faecalis, respectively. The aim of this study was to investigate the utility of these enterocins for in vivo treatment of systemic enterococcal infections.

METHODS AND RESULTS

The antimicrobial effect in blood was analysed and compared against the effect in saline. Colony forming unit counts revealed that the enterocins killed all the bacteria within 1 hour. Additionally, the bactericidal effect against E. faecalis was more rapid in blood, indicating a possible synergy between EntEJ97 and blood. Importantly, no enterocin resistant mutants emerged in these experiments. Injecting the enterocins intraperitoneally in an in vivo mouse model and using fluorescence and minimum inhibitory concentration determination to estimate concentrations of the peptides in plasma, indicate that the enterocins exist in circulation in therapeutic concentrations. Alanine aminotransferase detection, and haemolysis analysis indicates that there is no detectable liver damage or haemolytic effect after injection.

CONCLUSIONS

The study revealed that EntK1 and EntEJ97 are able to kill all bacteria ex vivo in the presence of blood. In vivo experiments determine that the enterocins exist in circulation in therapeutic concentrations without causing liver damage or haemolysis. Future experiments should test these peptides for treatment of infection in a relevant in vivo model.

Role of membrane vesicles in the transmission of vancomycin resistance in Enterococcus faecium

Clonal transmission and horizontal gene transfer (HGT) contribute to the spread of vancomycin-resistant enterococci (VRE) in global healthcare. Our study investigated vesiduction, a HGT mechanism via membrane vesicles (MVs), for vanA and vanB genes that determine vancomycin resistance. We isolated MVs for VRE of different sequence types (STs) and analysed them by nanoparticle tracking analysis. Selected MV samples were subjected to DNA sequence analysis. In resistance transfer experiments, vancomycin-susceptible enterococci were exposed to MVs and bacterial supernatants of VRE. Compared to bacteria grown in lysogeny broth (MVs/LB), cultivation under vancomycin stress (MVs/VAN) resulted in increased particle concentrations of up to 139-fold (ST80). As a key finding, we could show that VRE isolates of ST80 and ST117 produced remarkably more vesicles at subinhibitory antibiotic concentrations (approx. 9.2 × 1011 particles/ml for ST80 and 2.4 × 1011 particles/ml for ST117) than enterococci of other STs (range between 1.8 × 1010 and 5.3 × 1010 particles/ml). In those MV samples, the respective resistance genes vanA and vanB were completely verifiable using sequence analysis. Nevertheless, no vancomycin resistance transfer via MVs to vancomycin-susceptible Enterococcus faecium was phenotypically detectable. However, our results outline the potential of future research on ST-specific MV properties, promising new insights into VRE mechanisms.

A simple solid media assay for detection of synergy between bacteriophages and antibiotics

The emergence of antibiotic resistant bacteria (ARB) has necessitated the development of alternative therapies to deal with this global threat. Bacteriophages (viruses that target bacteria) that kill ARB are one such alternative. While phages have been used clinically for decades with inconsistent results, a number of recent advances in phage selection, propagation and purification have enabled a reevaluation of their utility in contemporary clinical medicine. In most phage therapy cases, phages are administered in combination with antibiotics to ensure that patients receive the standard-of-care treatment. Some phages may work cooperatively with antibiotics to eradicate ARB, as often determined using non-standardized broth assays. We sought to develop a solid media-based assay to assess cooperativity between antibiotics and phages to offer a standardized platform for such testing. We modeled the interactions that occur between antibiotics and phages on solid medium to measure additive, antagonistic, and synergistic interactions. We then tested the method using different bacterial isolates, and identified a number of isolates where synergistic interactions were identified. These interactions were not dependent on the specific organism, phage family, or antibiotic used. A priori susceptibility to the antibiotic or the specific phage were not requirements to observe synergistic interactions. Our data also confirm the potential for the restoration of vancomycin to treat Vancomycin Resistant Enterococcus (VRE) when used in combination with phages. Solid media assays for the detection of cooperative interactions between antibiotics and phages can be an accessible technique adopted by clinical laboratories to evaluate antibiotic and phage choices in phage therapy.

Top-Down Genomic Surveillance Approach To Investigate the Genomic Epidemiology and Antibiotic Resistance Patterns of Enterococcus faecium Detected in Cancer Patients in Arkansas

Control of hospital-associated Enterococcus faecium infection is a strenuous task due to the difficulty of identifying transmission routes and the persistence of this nosocomial pathogen despite the implementation of infection control measures that have been successful with other important nosocomial pathogens. This study provides a comprehensive analysis of over 100 E. faecium isolates collected from 66 cancer patients at the University of Arkansas for Medical Sciences (UAMS) between June 2018 and May 2019. In the top-down approach used in this study, we employed, in addition to the 106 E. faecium UAMS isolates, a filtered set of 2,167 E. faecium strains from the GenBank database to assess the current population structure of E. faecium species and, consequently, to identify the lineages associated with our clinical isolates. We then evaluated the antibiotic resistance and virulence profiles of hospital-associated strains from the species pool, focusing on antibiotics of last resort, to establish an updated classification of high-risk and multidrug-resistant nosocomial clones. Further investigation of the clinical isolates collected from UAMS patients using whole-genome sequencing analytical methodologies (core genome multilocus sequence typing [cgMLST], core single nucleotide polymorphism [coreSNP] analysis, and phylogenomics), with the addition of patient epidemiological data, revealed a polyclonal outbreak of three sequence types occurring simultaneously in different patient wards. The integration of genomic and epidemiological data collected from the patients increased our understanding of the relationships and transmission dynamics of the E. faecium isolates. Our study provides new insights into genomic surveillance of E. faecium to assist in monitoring and further limiting the spread of multidrug-resistant E. faecium. IMPORTANCE Enterococcus faecium is a member of the gastrointestinal microbiota. Although its virulence is low in healthy, immunocompetent individuals, E. faecium has become the third leading cause of health care-associated infections in the United States. This study provides a comprehensive analysis of over 100 E. faecium isolates collected from cancer patients at the University of Arkansas for Medical Sciences (UAMS). We employed a top-down analytical approach (from population genomics to molecular biology) to classify our clinical isolates into their genetic lineages and thoroughly evaluate their antibiotic resistance and virulence profiles. The addition of patient epidemiological data to the whole-genome sequencing analytical methodologies performed in the study allowed us to increase our understanding of the relationships and transmission dynamics of the E. faecium isolates. This study provides new insights into genomic surveillance of E. faecium to help monitor and further limit the spread of multidrug-resistant E. faecium.

Previous antibiotic therapy as independent risk factor for the presence of vancomycin-resistant enterococci in surgical inpatients. Results from a matched case-control study

BACKGROUND

Investigation of risk factors for the presence of vancomycin-resistant enterococci (VRE) in inpatients on surgical wards and associated intensive care units of a German tertiary care hospital.

METHODS

A single-centre retrospective matched case-control study was performed with surgical inpatients admitted between July 2013 and December 2016. Patients with in-hospital detection of VRE later than 48 h after admission were included and comprised 116 VRE-positive cases and 116 VRE-negative matched controls. VRE isolates of cases were typed by multi-locus sequence typing.

RESULTS

ST117 was identified as the dominant VRE sequence type. Next to length of stay in hospital or on an intensive care unit and previous dialysis the case-control study revealed previous antibiotic therapy as a risk factor for the in-hospital detection of VRE. The antibiotics piperacillin/tazobactam, meropenem, and vancomycin were associated with the highest risks. After taking into account length of stay in hospital as possible confounder other potential contact-related risk factors such as previous sonography, radiology, central venous catheter, and endoscopy were not significant.

CONCLUSIONS

Previous dialysis and previous antibiotic therapy were identified as independent risk factors for the presence of VRE in surgical inpatients.

Clinical manifestations, characteristics, and outcome of infections caused by vancomycin-resistant enterococci at a tertiary care center in Lebanon: A case-case-control study

BACKGROUND

Vancomycin-resistant enterococci (VRE) are prevalent infectious agents that particularly affect critically-ill patients, and they are on the rise in Lebanon. We aim at determining the potential risk factors and complications for VRE and vancomycin-susceptible enterococci (VSE) infections in a hospital setting and identify risk factors for in-hospital mortality.

METHODS

A case-case-control study design was used where patients with VRE and VSE were included as two separate groups and each group was compared to uninfected controls. We also constructed binary regression models to detect risk factors that were associated with the acquisition of a VRE or a VSE infection. We also identified independent mortality predictors for all patients with enterococcal infection as well as patients with only a VRE infection.

RESULTS

A total of 142 patients with enterococcal infections (VRE and VSE) were compared to 142 in-patients not infected with Enterococcus spp. independent risk factors for a VRE infection were steroid therapy within 30 days and the presence of another infection preceding the VRE infection (aOR 15.4, 95 % CI 2.4-99.3 and 23.9, 95 % CI 3.9-1482, respectively). An independent risk factor for VSE was diabetes mellitus (aOR 5.4, 95 % CI 1.1-26.6). Based on these risk factors, we developed a risk score to be used in quantifying the risk of VRE in a patient with an enterococcal infection. Male sex and low albumin were significant risk factors for mortality in our patient cohort.

CONCLUSIONS

VRE and VSE infections have distinct risk factors that can be used to guide empiric antimicrobial therapy.

Extending outbreak investigation with machine learning and graph theory: Benefits of new tools with application to a nosocomial outbreak of a multidrug-resistant organism

OBJECTIVE

From January 1, 2018, until July 31, 2020, our hospital network experienced an outbreak of vancomycin-resistant enterococci (VRE). The goal of our study was to improve existing processes by applying machine-learning and graph-theoretical methods to a nosocomial outbreak investigation.

METHODS

We assembled medical records generated during the first 2 years of the outbreak period (January 2018 through December 2019). We identified risk factors for VRE colonization using standard statistical methods, and we extended these with a decision-tree machine-learning approach. We then elicited possible transmission pathways by detecting commonalities between VRE cases using a graph theoretical network analysis approach.

RESULTS

We compared 560 VRE patients to 86,684 controls. Logistic models revealed predictors of VRE colonization as age (aOR, 1.4 (per 10 years), with 95% confidence interval [CI], 1.3-1.5; P < .001), ICU admission during stay (aOR, 1.5; 95% CI, 1.2-1.9; P < .001), Charlson comorbidity score (aOR, 1.1; 95% CI, 1.1-1.2; P < .001), the number of different prescribed antibiotics (aOR, 1.6; 95% CI, 1.5-1.7; P < .001), and the number of rooms the patient stayed in during their hospitalization(s) (aOR, 1.1; 95% CI, 1.1-1.2; P < .001). The decision-tree machine-learning method confirmed these findings. Graph network analysis established 3 main pathways by which the VRE cases were connected: healthcare personnel, medical devices, and patient rooms.

CONCLUSIONS

We identified risk factors for being a VRE carrier, along with 3 important links with VRE (healthcare personnel, medical devices, patient rooms). Data science is likely to provide a better understanding of outbreaks, but interpretations require data maturity, and potential confounding factors must be considered.

Development and Validation of a Tool for the Prediction of Vancomycin-Resistant Enterococci Colonization Persistence-the PREVENT Score

Vancomycin-resistant enterococci (VRE) are nosocomial pathogens with increasing prevalence worldwide. Extensive hygiene measures have been established to prevent infection transmission in hospitals. Here, we developed a predictive score system (the predictive vancomycin-resistant enterococci [PREVENT] score) to identify the clearance or persistence in patients with a history of VRE carrier status at readmission. Over a cumulative 3-year period, patients with a positive VRE carrier status were included. The study population was recruited in two successive time periods and separated into training data for predictive score development and validation data for evaluation of the predictive power. The risk factors for persistent VRE colonization were analyzed in a univariable analysis before development of a logistic regression model based on the potential risk factors. The score points were determined proportionally to the beta coefficients of the logistic regression model. The data from 448 (79%) patients were used as the training data, and those from 119 (21%) as the validation data. Multivariable analysis revealed the following variables as independent risk factors: age of ≥60 years, hemato-oncological disease, cumulative antibiotic treatment for >4 weeks, and a VRE infection. The resulting logistic regression model exhibited an acceptable area under the curve (AUC) of 0.81 (95% confidence interval [CI], 0.72 to 0.91). The predictive score system had a sensitivity of 82% (95% CI, 65 to 93%) and a specificity of 77% (95% CI, 66 to 85%). The developed predictive score system is a useful tool to assess the VRE carrier status of patients with a history of VRE colonization. On the basis of this risk assessment, more focused and cost-effective infection control measures can be implemented. IMPORTANCE Given the increasing relevance of VRE as nosocomial pathogens worldwide, infection prevention and control measures, including patient isolation and contact precautions, are indispensable to avoid their spread in the hospital setting. In this study, we developed and validated the PREVENT score, a tool for rapid risk assessment of VRE persistence in patients with a history of previous VRE colonization. The score is designed to be easily performed, employing clinical information available in a regular admission setting and immediately providing information to inform the decision of whether to adopt patient isolation and contact precautions during the hospital stay. After validation, the score was shown to accurately identify patients with persistent VRE colonization upon admission, representing a suitable option as (i) a complementary method yielding preliminary results significantly more quickly than culture-based VRE detection techniques and (ii) an alternative strategy for VRE detection in settings in which microbiological VRE screening is not routinely performed due to limited resources.

Clostridioides difficile and Vancomycin-Resistant Enterococci in COVID-19 Patients with Severe Pneumonia

Broad-spectrum antibiotics administered to patients with severe COVID-19 pneumonia pose a risk of infection caused by Clostridioides difficile. This risk is reduced mainly by strict hygiene measures and early de-escalation of antibiotic therapy. Recently, oral vancomycin prophylaxis (OVP) has also been discussed. This retrospective study aimed to assess the prevalence of C. difficile in critical COVID-19 patients staying in an intensive care unit of a tertiary hospital department of anesthesiology, resuscitation, and intensive care from November 2020 to May 2021 and the rates of vancomycin-resistant enterococci (VRE) after the introduction of OVP and to compare the data with those from controls in the pre-pandemic period (November 2018 to May 2019). During the COVID-19 pandemic, there was a significant increase in toxigenic C. difficile rates to 12.4% of patients, as compared with 1.6% in controls. The peak rates were noted in February 2021 (25% of patients), immediately followed by initiation of OVP, changes to hygiene precautions, and more rapid de-escalation of antibiotic therapy. Subsequently, toxigenic C. difficile detection rates started to fall. There was a nonsignificant increase in VRE detected in non-gastrointestinal tract samples to 8.9% in the COVID-19 group, as compared to 5.3% in the control group. Molecular analysis confirmed mainly clonal spread of VRE.

Impact of Clostridioides difficile Therapy on Nosocomial Acquisition of Vancomycin-Resistant Enterococci

Vancomycin is frequently used for the treatment of C. difficile infections (CDI). There are concerns that this might increase the risk of selecting vancomycin resistant enterococci (VRE). Here, we evaluated whether there is an increased risk of VRE acquisition following vancomycin for CDI specific treatment. Patients with CDI, metronidazole, or oral vancomycin treatment and without preexisting VRE were monitored for VRE acquisition. VRE isolates from patients with acquired and preexisting colonization were collected and subjected to whole genome sequencing. In total, 281 patients (median age 56 years, 54% of the male sex) presented with toxin positive C. difficile. Of them, 170 patients met the inclusion criteria, comprising 37 patients treated with metronidazole and 133 treated with oral vancomycin. In total, 14 patients meeting the inclusion criteria acquired VRE (vancomycin: n = 11; metronidazole: n = 3). Statistical analysis revealed no significant differences between both VRE acquisition rates. Genetic comparison of detected VRE isolates resulted in eight clusters of closely related genotypes comprising acquired and preexisting strains. Our results suggest that vancomycin and metronidazole likewise increase the risk of VRE acquisition. Genetic comparison indicates that VRE acquisition is a result of both antibiotic selection and pathogen transmission.

A nosocomial cluster of vancomycin resistant enterococci among COVID-19 patients in an intensive care unit

BACKGROUND

Currently, hospitals have been forced to divert substantial resources to cope with the ongoing coronavirus disease 2019 (COVID-19) pandemic. It is unclear if this situation will affect long-standing infection prevention practices and impact on healthcare associated infections. Here, we report a nosocomial cluster of vancomycin-resistant enterococci (VRE) that occurred on a COVID-19 dedicated intensive care unit (ICU) despite intensified contact precautions during the current pandemic. Whole genome sequence-based typing (WGS) was used to investigate genetic relatedness of VRE isolates collected from COVID-19 and non-COVID-19 patients during the outbreak and to compare them to environmental VRE samples.

METHODS

Five VRE isolated from patients (three clinical and two screening samples) as well as 11 VRE and six vancomycin susceptible Enterococcus faecium (E. faecium) samples from environmental sites underwent WGS during the outbreak investigation. Isolate relatedness was determined using core genome multilocus sequence typing (cgMLST).

RESULTS

WGS revealed two genotypic distinct VRE clusters with genetically closely related patient and environmental isolates. The cluster was terminated by enhanced infection control bundle strategies.

CONCLUSIONS

Our results illustrate the importance of continued adherence to infection prevention and control measures during the COVID-19 pandemic to prevent VRE transmission and healthcare associated infections.

Chlorhexidine bathing to prevent healthcare-associated vancomycin-resistant Enterococcus infections: A cluster quasi-experimental controlled study at intensive care units

BACKGROUND/PURPOSE

Vancomycin-resistant Enterococcus (VRE), a multidrug-resistant, difficult-to-treat pathogen of healthcare-associated infections (HAIs), is now endemic at many intensive care units (ICUs). Chlorhexidine (CHG) bathing is a simple and highly effective intervention to decrease VRE acquisition, but its effect on VRE-HAIs has not been assessed in prospective studies at ICUs.

METHODS

This is a cluster quasi-experimental controlled study. Under active VRE surveillance and contact isolation of all identified VRE carriers, four ICUs were assigned to provide 2% CHG bathing for all patients on a daily basis (CHG group) during the intervention period, while another four ICUs were assigned to provide standard care without CHG bathing for all patients (standard care group) during the same period.

RESULTS

The CHG group (n = 1501) had a 62% lower crude incidence of VRE-HAIs during the intervention period, compared with the baseline period (1.0 vs. 2.6 per thousand patient-days, P = 0.009), while VRE-HAIs incidence did not change in standard care group (n = 3299) (1.1 vs. 0.5 per thousand patient-days, P = 0.139). In multivariable analyses, CHG bathing was independently associated with a 70% lower risk of VRE-HAIs (adjusted odds ratio [OR] 0.3, 95% confidence interval [CI], 0.2 to 0.7, P = 0.006). In contrast, standard care during the same period had no effect on the risk of VRE-HAIs (adjusted OR 1.8, 95% CI: 0.7 to 4.7, P = 0.259).

CONCLUSION

CHG bathing is a highly effective approach to prevent VRE-HAIs at ICUs, in the context of active VRE surveillance with contact isolation.