Recommendations for the successful control of a large outbreak of vancomycin-resistant Enterococcus faecium in a non-endemic hospital setting

Genomic sequencing surveillance of patients colonized with vancomycin-resistant Enterococcus (VRE) improves detection of hospital-associated transmission

Background

Vancomycin-resistant enterococcal (VRE) infections pose significant challenges in healthcare. Transmission dynamics of VRE are complex, often involving patient colonization and subsequent transmission through various healthcare-associated vectors. We utilized a whole genome sequencing (WGS) surveillance program at our institution to better understand the contribution of clinical and colonizing isolates to VRE transmission.

Methods

We performed whole genome sequencing on 352 VRE clinical isolates collected over 34 months and 891 rectal screening isolates collected over a 9-month nested period, and used single nucleotide polymorphisms to assess relatedness. We then performed a geo-temporal transmission analysis considering both clinical and rectal screening isolates compared with clinical isolates alone, and calculated 30-day outcomes of patients.

Results

VRE rectal carriage constituted 87.3% of VRE acquisition, with an average monthly acquisition rate of 7.6 per 1000 patient days. We identified 185 genetically related clusters containing 2-42 isolates and encompassing 69.6% of all isolates in the dataset. The inclusion of rectal swab isolates increased the detection of clinical isolate clusters (from 53% to 67%, P<0.01). Geo-temporal analysis identified hotspot locations of VRE transmission. Patients with clinical VRE isolates that were closely related to previously sampled rectal swab isolates experienced 30-day ICU admission (17.5%), hospital readmission (9.2%), and death (13.3%).

Conclusions

Our findings describe the high burden of VRE transmission at our hospital and shed light on the importance of using WGS surveillance of both clinical and rectal screening isolates to better understand the transmission of this pathogen. This study highlights the potential utility of incorporating WGS surveillance of VRE into routine hospital practice for improving infection prevention and patient safety.

Perspectives on research needs in healthcare epidemiology and antimicrobial stewardship: what's on the horizon - Part I

In this overview, we articulate research needs and opportunities in the field of infection prevention that have been identified from insights gained during operative infection prevention work, our own research in healthcare epidemiology, and from reviewing the literature. The 10 areas of research need are: 1) transmissions and interruptions, 2) personal protective equipment and other safety issues in occupational health, 3) climate change and other crises, 4) device, diagnostic, and antimicrobial stewardship, 5) implementation and de-implementation, 6) health care outside the acute care hospital, 7) low- and middle-income countries, 8) networking with the "neighbors", 9) novel research methodologies, and 10) the future state of surveillance. An introduction and chapters 1-5 are presented in part I of the article, and chapters 6-10 and the discussion in part II. There are many barriers to advancing the field, such as finding and motivating the future IP workforce including professionals interested in conducting research, a constant confrontation with challenges and crises, the difficulty of performing studies in a complex environment, the relative lack of adequate incentives and funding streams, and how to disseminate and validate the often very local quality improvement projects. Addressing research gaps now (i.e., in the postpandemic phase) will make healthcare systems more resilient when facing future crises.

Vancomycin-resistant enterococci (VRE) in hospital settings across European borders: a scoping review comparing the epidemiology in the Netherlands and Germany

The rising prevalence of vancomycin-resistant enterococci (VRE) is a matter of concern in hospital settings across Europe without a distinct geographical pattern. In this scoping review, we compared the epidemiology of vancomycin-resistant Enterococcus spp. in hospitals in the Netherlands and Germany, between 1991 and 2022. We searched PubMed and summarized the national antibiotic resistance surveillance data of the two countries. We included 46 studies and summarized national surveillance data from the NethMap in the Netherlands, the National Antimicrobial Resistance Surveillance database in Germany, and the EARS-Net data. In total, 12 studies were conducted in hospitals in the Netherlands, 32 were conducted in German hospitals, and an additional two studies were conducted in a cross-border setting. The most significant difference between the two countries was that studies in Germany showed an increasing trend in the prevalence of VRE in hospitals, and no such trend was observed in studies in the Netherlands. Furthermore, in both Dutch and German hospitals, it has been revealed that the molecular epidemiology of VREfm has shifted from a predominance of vanA towards vanB over the years. According to national surveillance reports, vancomycin resistance in Enterococcus faecium clinical isolates fluctuates below 1% in Dutch hospitals, whereas it follows an increasing trend in German hospitals (above 20%), as supported by individual studies. This review demonstrates that VRE is more frequently encountered in German than in Dutch hospitals and discusses the underlying factors for the difference in VRE occurrence in these two neighboring countries by comparing differences in healthcare systems, infection prevention control (IPC) guidelines, and antibiotic use in the Netherlands and Germany.

Contact investigations for antibiotic-resistant bacteria: a mixed-methods study of patients' comprehension of and compliance with self-sampling requests post-discharge

BACKGROUND

Contact investigation is an important tool to identify unrecognized patients who are colonized with antibiotic-resistant bacteria. Many Dutch hospitals include already discharged contact patients by sending them a self-sampling request at home, incl. an information letter and sampling materials. Each hospital composes these information letters on their own initiative, however, whether discharged patients comprehend and comply with these requests remains unclear. Therefore, the aim was to provide insight into patients' comprehension of and self-reported compliance with self-sampling requests post-discharge.

METHODS

This mixed-methods study was performed in eight Dutch hospitals. First, the Common European Framework of Reference (CEFR) language level of self-sampling request letters was established. Second, a questionnaire about patients' comprehension of the letter, self-reported compliance, and reasons for compliance or non-compliance were sent to patients that received such a request in 2018/2019. Finally, a random selection of questionnaire respondents was interviewed between January and March 2020 to gain additional insights.

RESULTS

CEFR levels of 15 letters were established. Four letters were assigned level B1, four letters B1-B2, and seven letters B2. The majority of patients reported good comprehension of the letter they had received. Conversely, some respondents indicated that information about the bacterium (18.4%), the way in which results would be communicated (18.1%), and the self-sampling instructions (9.7%) were (partially) unclear. Furthermore, self-reported compliance was high (88.8%). Reasons to comply were personal health (84.3%), the health of others (71.9%), and general patient safety (96.1%). Compliant patients appeared to have a need for confirmation, wanted to protect family and/or friends, and felt they were providing the hospital the ability to control the transmission of antibiotic-resistant bacteria. Although a limited number of non-compliant patients responded to the questionnaire, it seemed that more patients did not comply with self-sampling requests when they received a letter in a higher CEFR-level (B2) compared to a lower CEFR-level (< B2) (9.8% vs. 2.5%, P = 0.049).

CONCLUSIONS

This study showed an overall good comprehension of and high self-reported compliance with self-sampling requests post-discharge. Providing balanced information in self-sampling request letters has the potential to reduce patient's ambiguity and concerns, and can cause increased compliance with self-sampling requests.

Contact tracing for vancomycin-resistant Enterococcus faecium (VRE): evaluation of the Dutch policy of quintuple screening cultures

Detection of vancomycin-resistant Enterococcus faecium (VRE) is hampered by low sensitivity of rectal swab cultures. This study aimed to define the number of screening cultures needed to increase sensitivity to detect VRE transmission, and to determine time from presumed exposure to detectable colonization. In a tertiary care setting, we retrospectively analyzed data from 9 VRE outbreaks. As a proxy or estimation for time to detectable colonization, the time between first positive culture of the presumed index patient and that of their contacts was determined. Only 64% of secondary cases were positive in the first out of five cultures. By using the first three out of five rectal swabs, 89% (95%CI: 78-95%) of all secondary cases would have been identified. The median number of days between the positive culture of the index patient and the first positive culture of secondary cases was 9 days. Eleven percent of secondary cases would have been missed if only three rectal samples would have been obtained. Furthermore, our results show that one or more rectal swabs taken around day 9 after presumed exposure should at least be included in the screening approach. In our setting, obtaining a fourth and a fifth rectal swab showed a relevant additional value compared to only one to three swabs. Our findings are useful for determining the most effective VRE contact tracing approach to prevent transmission.

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.

Effectiveness of patient and staff cohorting to reduce the risk of vancomycin-resistant enterococcus (VRE) acquisition: a retrospective cohort study during a VRE outbreak in Japan

BACKGROUND

Patient and staff cohorting is part of a bundle approach in the response to multi-drug-resistant organisms, but its effectiveness is not fully clarified. This study compared the risks of acquiring vancomycin-resistant Enterococcus faecium (VREfm) at a hospital during a VREfm outbreak based on contact characteristics in order to better understand the effectiveness of cohorting.

METHODS

Exposure came from contact with patients with VREfm (infectors), including existing patients with VREfm and patients who acquired VREfm during the study period. Contact was defined as length of contact time, degree of sharing space, and care by the same nurses as those caring for infectors between January and March 2018. The outcome was VREfm acquisition as determined through monthly stool or rectal screening cultures. Incidence rates were calculated based on contact patterns, and incidence rate ratios (IRRs) were compared.

FINDINGS

Among 272 inpatients (4038 patient-days), 43 patients acquired VREfm with the same or similar pulsotype. Incidence rates were 8.45 per 1000 patient-days when susceptible inpatients were on the same ward as an infector but cared for by different nurses (reference), 16.96 when susceptible inpatients were on the same ward as an infector and cared for by the same nurses [IRR 2.01, 95% confidence interval (CI) 0.62-10.28], and 52.91 when susceptible inpatients shared a room with an infector (IRR 6.26, 95% CI 1.61-35.40).

CONCLUSION

Compared with susceptible inpatients in a different room from infectors and not being cared for by the same nurses, the risk of VREfm acquisition could be six times higher for susceptible inpatients who are in the same room as infectors, and could be double for susceptible inpatients cared for by the same nurses as infectors.

Vancomycin-resistant Enterococcus faecium: admission prevalence, sequence types and risk factors-a cross-sectional study in seven German university hospitals from 2014 to 2018

OBJECTIVES

Assessment of vancomycin-resistant Enterococcus faecium (VREfm) prevalence upon hospital admission and analysis of risk factors for colonization.

METHODS

From 2014 to 2018, patients were recruited within 72 hours of admission to seven participating German university hospitals, screened for VREfm and questioned for potential risk factors (prior multidrug-resistant organism detection, current/prior antibiotic consumption, prior hospital, rehabilitation or long-term care facility stay, international travel, animal contact and proton pump inhibitor [PPI]/antacid therapy). Genotype analysis was done using cgMLST typing. Multivariable analysis was performed.

RESULTS

In 5 years, 265 of 17,349 included patients were colonized with VREfm (a prevalence of 1.5%). Risk factors for VREfm colonization were age (adjusted OR [aOR], 1.02; 95% CI, 1.01-1.03), previous (aOR, 2.71; 95% CI, 1.87-3.92) or current (aOR, 2.91; 95% CI, 2.60-3.24) antibiotic treatment, prior multidrug-resistant organism detection (aOR, 2.83; 95% CI, 2.21-3.63), prior stay in a long-term care facility (aOR, 2.19; 95% CI, 1.62-2.97), prior stay in a hospital (aOR, 2.91; 95% CI, 2.05-4.13) and prior consumption of PPI/antacids (aOR, 1.29; 95% CI, 1.18-1.41). Overall, the VREfm admission prevalence increased by 33% each year and 2% each year of life. 250 of 265 isolates were genotyped and 141 (53.2%) of the VREfm were the emerging ST117. Multivariable analysis showed that ST117 and non-ST117 VREfm colonized patients differed with respect to admission year and prior multidrug-resistant organism detection.

DISCUSSION

Age, healthcare contacts and antibiotic and PPI/antacid consumption increase the individual risk of VREfm colonization. The VREfm admission prevalence increase in Germany is mainly driven by the emergence of ST117.

Nosocomial outbreak of vancomycin-resistant Enterococcus faecium (VRE) ST796, Switzerland, 2017 to 2020

A large clonal outbreak caused by vancomycin-resistant Enterococcus faecium (VRE) affected the Bern University Hospital group from the end of December 2017 until July 2020. We describe the characteristics of the outbreak and the bundle of infection prevention and control (IPC) measures implemented. The outbreak was first recognised when two concomitant cases of VRE bloodstream infection were identified on the oncology ward. During 32 months, 518 patients in the 1,300-bed hospital group were identified as vanB VRE carriers. Eighteen (3.5%) patients developed an invasive infection, of whom seven had bacteraemia. In 2018, a subset of 328 isolates were analysed by whole genome sequencing, 312 of which were identified as sequence type (ST) 796. The initial IPC measures were implemented with a focus on the affected wards. However, in June 2018, ST796 caused another increase in cases, and the management strategy was intensified and escalated to a hospital-wide level. The clinical impact of this large nosocomial VRE outbreak with the emergent clone ST796 was modest. A hospital-wide approach with a multimodal IPC bundle was successful against this highly transmissible strain.

High adherence to national IPC guidelines as key to sustainable VRE control in Swiss hospitals: a cross-sectional survey

Background

Vancomycin resistant enterococci (VRE) are on the rise in many European hospitals. In 2018, Switzerland experienced its largest nosocomial VRE outbreak. The national center for infection prevention (Swissnoso) elaborated recommendations for controlling this outbreak and published guidelines to prevent epidemic and endemic VRE spread. The primary goal of this study was to evaluate adherence to this new guideline and its potential impact on the VRE epidemiology in Swiss acute care hospitals.

Methods

In March 2020, Swissnoso distributed a survey among all Swiss acute care hospitals. The level of adherence as well as changes of infection prevention and control (IPC) strategies in the years 2018 and 2019 after publication of the national guidelines were asked along with an inventory on VRE surveillance and outbreaks.

Results

Data of 97/146 (66%) participants were available, representing 81.6% of all acute care beds operated in Switzerland in 2019. The vast majority—72/81 (88%) responding hospitals—have entirely or largely adopted our new national guideline. 38/51 (74.5%) hospitals which experienced VRE cases were significantly more likely to have changed their IPC strategies than those 19/38 (50%) hospitals without VRE cases p = 0.017). The new IPC guidelines included (1) introduction of targeted admission screening in 89.5%, (2) screening of close contacts of VRE cases in 56%, and (3) contact precaution for suspected VRE cases 58% of these hospitals. 52 (54%) hospitals reported 569 new VRE cases in 2018 including 14 bacteremia, and 472 new cases in 2019 with 10 bacteremia. The ten largest outbreaks encountered between 2018 and 2019 included 671 VRE cases, of which most (93.4%) consisted of colonization events, 29 (4.3%) infections and 15 (2.2%) bacteremia.

Conclusion

Wide adoption of this VRE control guideline seemed to have a positive effect on VRE containment in Swiss acute care hospitals over two years, even if its long-term impact on the VRE epidemiology remains to be evaluated. Broad dissemination and strict implementation of a uniform national guideline may therefore serve as model for other countries to fight VRE epidemics on a national level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-022-01051-9.

Interhospital transmission of vancomycin-resistant Enterococcus faecium in Aomori, Japan

Background

Spread of vancomycin-resistant Enterococcus (VRE) is a global concern as a significant cause of healthcare-associated infections. A series of VRE faecium (VREf) outbreaks caused by clonal propagation due to interhospital transmission occurred in six general hospitals in Aomori prefecture, Japan.

Methods

The number of patients with VREf was obtained from thirty seven hospitals participating in the local network of Aomori prefecture. Thirteen hospitals performed active screening tests for VRE. Whole genome sequencing analysis was performed.

Results

The total number of cases with VREf amounted to 500 in fourteen hospitals in Aomori from Jan 2018 to April 2021. It took more than three years for the frequency of detection of VRE to return to pre-outbreak levels. The duration and size of outbreaks differed between hospitals according to the countermeasures available at each hospital. Whole genome sequencing analysis indicated vanA-type VREf ST1421 for most samples from six hospitals.

Conclusions

This was the first multi-jurisdictional outbreak of VREf sequence type 1421 in Japan. In addition to strict infection control measures, continuous monitoring of VRE detection in local medical regions and smooth and immediate communication among hospitals are required to prevent VREf outbreaks.

Controlling an Unprecedented Outbreak with Vancomycin-Resistant Enterococcus faecium in Germany, October 2015 to November 2019

Hospital outbreaks with vancomycin-resistant enterococci (VRE) pose a serious health threat and a challenge to infection prevention and control (IPC). We herein report on a VRE outbreak of unprecedented extent in Southern Germany (October 2015-November 2019). We used descriptive epidemiology and whole-genome sequencing (WGS) for a detailed outbreak investigation. Of the 2905 cases, 2776 (95.3%) were colonized, whereas from 127 (3.7%), VRE could be isolated from otherwise sterile body fluids or sites unlikely for enterococci colonization. Cases had a median age of 78 years (IQR 68-84) and 1339/2905 (46%) were female. The majority of isolates sequenced belonged to the clonal lineage ST80/CT1013 (212/397, 53%). Nosocomial transmission was observed as well as the constant import of VRE into the hospital. Extensive IPC measures were implemented and terminated the outbreak in late 2019, eventually. Our study shows that the combination of epidemiological and genomic analyses is indispensable for comprehensive outbreak investigations. The adaptation of IPC measures to these findings, their timely implementation, and strict execution also allow containment of large VRE outbreaks in hospital settings.

Spatiotemporal prediction of vancomycin-resistant Enterococcus colonisation

BACKGROUND

Vancomycin-resistant enterococci (VRE) is the cause of severe patient health and monetary burdens. Antibiotic use is a confounding effect to predict VRE in patients, but the antibiotic use of patients who may have frequented the same ward as the patient in question is often neglected. This study investigates how patient movements between hospital wards and their antibiotic use can explain the colonisation of patients with VRE.

METHODS

Intrahospital patient movements, antibiotic use and PCR screening data were used from a hospital in the Netherlands. The PageRank algorithm was used to calculate two daily centrality measures based on the spatiotemporal graph to summarise the flow of patients and antibiotics at the ward level. A decision tree model was used to determine a simple set of rules to estimate the daily probability of patient VRE colonisation for each hospital ward. The model performance was improved using a random forest model and compared using 30% test sample.

RESULTS

Centrality covariates summarising the flow of patients and their antibiotic use between hospital wards can be used to predict the daily colonisation of VRE at the hospital ward level. The decision tree model produced a simple set of rules that can be used to determine the daily probability of patient VRE colonisation for each hospital ward. An acceptable area under the ROC curve (AUC) of 0.755 was achieved using the decision tree model and an excellent AUC of 0.883 by the random forest model on the test set. These results confirms that the random forest model performs better than a single decision tree for all levels of model sensitivity and specificity on data not used to estimate the models.

CONCLUSION

This study showed how the movements of patients inside hospitals and their use of antibiotics could predict the colonisation of patients with VRE at the ward level. Two daily centrality measures were proposed to summarise the flow of patients and antibiotics at the ward level. An early warning system for VRE can be developed to test and further develop infection prevention plans and outbreak strategies using these results.

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.

Failure of Vitek2 to reliably detect vanB-mediated vancomycin resistance in Enterococcus faecium

OBJECTIVES

The increasing prevalence of VRE necessitates their reliable detection, especially for low-level resistance mediated by vanB in Enterococcus faecium. In this prospective study we analysed if vanB-mediated vancomycin resistance can be reliably detected by Vitek2.

METHODS

One thousand, three hundred and forty-four enterococcal isolates from routine clinical specimens were tested by Vitek2 (bioMérieux, Nürtingen, Germany). Additionally, a bacterial suspension (with a turbidity equivalent to that of a 0.5 McFarland standard) was inoculated on chromID VRE screening agar (bioMérieux) and incubated for 48 h. If vancomycin tested susceptible by Vitek2 but growth was detected on the screening agar, PCR for vanA/vanB was performed (GeneXpert vanA/B test, Cepheid, Frankfurt, Germany). For isolates that tested susceptible to vancomycin by Vitek2 but were vanA/B positive, MICs were determined before and after cultivation in broth with increasing concentrations of vancomycin.

RESULTS

One hundred and fifty-six out of 491 E. faecium were VRE and were predominantly vanB positive (81.0%). Of these, Vitek2 did not identify 14 as VRE (sensitivity 91.0%). By broth microdilution 9/14 isolates demonstrated high MICs (≥32 mg/L) and 5/14 showed low vancomycin MICs, which did not increase despite vancomycin exposure. Three of the 14 isolates demonstrated growth on chromID VRE; after vancomycin exposure seven additional isolates were able to grow on chromID VRE.

CONCLUSIONS

Vitek2 fails to detect vanB-mediated vancomycin resistance consistently, especially, but not limited to, low-level resistance. As this may lead to treatment failure and further dissemination of vanB VRE, additional methods (e.g. culture on VRE screening agar or PCR) are necessary to reliably identify vanB-positive enterococci in clinical routine.

Management of a hospital-wide vancomycin-resistant Enterococcus faecium outbreak in a Dutch general hospital, 2014-2017: successful control using a restrictive screening strategy

Background

The emergence of vancomycin resistant enterococci poses a major problem in healthcare settings. Here we describe a hospital-wide outbreak of vancomycin-resistant Enterococcus faecium in a general hospital in The Netherlands in the period December 2014–February 2017. Due to late detection of the outbreak, a large cohort of approximately 25,000 (discharged) patients was classified as ‘VRE suspected’. Hereupon a mitigated screening and isolation policy, as compared with the national guideline, was implemented to control the outbreak.

Methods

After the outbreak was identified, a screening policy consisting of a single rectal swab culture (with enrichment broth) to discontinue isolation and removing ‘VRE suspected’ label in the electronic patient files for readmitted VRE suspected patients, was implemented. In addition to the on admission screening, periodic hospital-wide point prevalence screening, measures to improve compliance with standard infection control precautions and enhanced environmental cleaning were implemented to control the outbreak.

Results

Between September 2014 and February 2017, 140 patients were identified to be colonised by vanA mediated vancomycin-resistant Enterococcus faecium (VREfm). Two of these patients developed bacteraemia. AFLP typing showed that the outbreak was caused by a single clone. Extensive environmental contamination was found in multiple wards. Within nine months after the detection of the outbreak no new VRE cases were detected.

Conclusion

We implemented a control strategy based on targeted screening and isolation in combination with implementation of general precautions and environmental cleaning. The strategy was less stringent than the Dutch national guideline for VRE control. This strategy successfully controlled the outbreak, while it was associated with a reduction in the number of isolation days and the number of cultures taken.

Supplementary information

The online version contains supplementary material available at 10.1186/s13756-021-00906-x.

Systematic review on use, cost and clinical efficacy of automated decontamination devices

BACKGROUND

More evidence is emerging on the role of surface decontamination for reducing hospital-acquired infection (HAI). Timely and adequate removal of environmental pathogens leads to measurable clinical benefit in both routine and outbreak situations.

OBJECTIVES

This systematic review aimed to evaluate published studies describing the effect of automated technologies delivering hydrogen peroxide (H202) or ultra-violet (UV) light on HAI rates.

METHODS

A systematic review was performed using relevant search terms. Databases were scanned from January 2005 to March 2020 for studies reporting clinical outcome after use of automated devices on healthcare surfaces. Information collected included device type, overall findings; hospital and ward data; study location, length and size; antimicrobial consumption; domestic monitoring; and infection control interventions. Study sponsorship and duplicate publications were also noted.

RESULTS

While there are clear benefits from non-touch devices in vitro, we found insufficient objective assessment of patient outcome due to the before-and-after nature of 36 of 43 (84%) studies. Of 43 studies, 20 (47%) used hydrogen peroxide (14 for outbreaks) and 23 (53%) used UV technology (none for outbreaks). The most popular pathogen targeted, either alone or in combination with others, was Clostridium difficile (27 of 43 studies: 63%), followed by methicillin-resistant Staphylococcus aureus (MRSA) (16 of 43: 37%). Many owed funding and/or personnel to industry sponsorship (28 of 43: 65%) and most were confounded by concurrent infection control, antimicrobial stewardship and/or cleaning audit initiatives. Few contained data on device costs and rarely on comparable costs (1 of 43: 2%). There were expected relationships between the country hosting the study and location of device companies. None mentioned the potential for environmental damage, including effects on microbial survivors.

CONCLUSION

There were mixed results for patient benefit from this review of automated devices using H202 or UV for surface decontamination. Most non-outbreak studies lacked an appropriate control group and were potentially compromised by industry sponsorship. Concern over HAI encourages delivery of powerful disinfectants for eliminating pathogens without appreciating toxicity or cost benefit. Routine use of these devices requires justification from standardized and controlled studies to understand how best to manage contaminated healthcare environments.

Successful containment of two vancomycin-resistant Enterococcus faecium (VRE) outbreaks in a Dutch teaching hospital using environmental sampling and whole-genome sequencing

BACKGROUND

Vancomycin-resistant enterococci (VRE) may cause nosocomial outbreaks. This article describes all VRE carriers that were identified in 2018 at Elisabeth-Tweesteden Hospital, Tilburg, The Netherlands.

AIM

To investigate the genetic relatedness of VRE isolates and the possibility of a common environmental reservoir using environmental sampling and whole-genome sequencing (WGS).

METHODS

Infection control measures consisted of contact isolation, contact surveys, point prevalence screening, environmental sampling, cleaning and disinfection. VRE isolates were sequenced using a MiSeq sequencer (Illumina, San Diego, CA, USA), and assembled using SPAdes v.3.10.1. A minimal spanning tree and a neighbour joining tree based on allelic diversity of core-genome multi-locus sequence typing and accessory genes were created using Ridom SeqSphere+ software (Ridom GmbH, Münster, Germany).

FINDINGS

Over a 1-year period, 19 VRE carriers were identified; of these, 17 were part of two outbreaks. Before environmental cleaning and disinfection, 55 (14%) environmental samples were VRE-positive. Fifty-one isolates (23 patient samples and 28 environmental samples) were available for WGS analysis. Forty-four isolates were assigned to ST117-vanB, five were assigned to ST17-vanB, and two were assigned to ST80-vanB. Isolates from Outbreak 1 (N=22) and Outbreak 2 (N=22) belonged to ST117-vanB; however, WGS showed a different cluster type with 257 allelic differences.

CONCLUSION

WGS of two outbreak strains provided discriminatory information regarding genetic relatedness, and rejected the hypothesis of a common environmental reservoir. A high degree of environmental contamination was associated with higher VRE transmission. Quantification of environmental contamination may reflect the potential for VRE transmission and could therefore support the infection control measures.

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.

Therapeutic Options for Infections due to vanB Genotype Vancomycin-Resistant Enterococci

Enterococci are ubiquitous, facultative, anaerobic Gram-positive bacteria that mainly reside, as part of the normal microbiota, in the gastrointestinal tracts of several animal species, including humans. These bacteria have the capability to turn from a normal gut commensal organism to an invasive pathogen in patients debilitated by prolonged hospitalization, concurrent illnesses, and/or exposed to broad-spectrum antibiotics. The majority of vancomycin-resistant enterococcus (VRE) infections are linked to the vanA genotype; however, outbreaks caused by vanB-type VREs have been increasingly reported, representing a new challenge for effective antimicrobial treatment. Teicoplanin, daptomycin, fosfomycin, and linezolid are useful antimicrobials for infections due to vanB enterococci. In addition, new drugs have been developed (e.g., dalbavancin, telavancin, and tedizolid), new molecules will soon be available (e.g., eravacycline, omadacycline, and oritavancin), and new treatment strategies are progressively being used in clinical practice (e.g., combination therapies and bacteriophages). The aim of this article is to discuss the pathogenesis of infections due to enterococci harboring the vanB operon (vanBVRE) and their therapeutic, state-of-the-art, and future treatment options and provide a comprehensive and easy to use review for clinical purposes.

Enterococcus faecium: from microbiological insights to practical recommendations for infection control and diagnostics

Early in its evolution, Enterococcus faecium acquired traits that allowed it to become a successful nosocomial pathogen. E. faecium inherent tenacity to build resistance to antibiotics and environmental stressors that allows the species to thrive in hospital environments. The continual wide use of antibiotics in medicine has been an important driver in the evolution of E. faecium becoming a highly proficient hospital pathogen.For successful prevention and reduction of nosocomial infections with vancomycin resistant E. faecium (VREfm), it is essential to focus on reducing VREfm carriage and spread. The aim of this review is to incorporate microbiological insights of E. faecium into practical infection control recommendations, to reduce the spread of hospital-acquired VREfm (carriage and infections). The spread of VREfm can be controlled by intensified cleaning procedures, antibiotic stewardship, rapid screening of VREfm carriage focused on high-risk populations, and identification of transmission routes through accurate detection and typing methods in outbreak situations. Further, for successful management of E. faecium, continual innovation in the fields of diagnostics, treatment, and eradication is necessary.

Increase of vancomycin-resistant Enterococcus faecium strain type ST117 CT71 at Charité - Universitätsmedizin Berlin, 2008 to 2018

BACKGROUND

In addition to an overall rise in vancomycin-resistant Enterococcus faecium (VREfm), an increase in certain strain types marked by sequence type (ST) and cluster type (CT) has been reported in Germany over the past few years. Outbreak analyses at Charité - Universitätsmedizin Berlin revealed the frequent occurrence of VREfm ST117 CT71 isolates in 2017 and 2018. To investigate whether ST117 CT71 have emerged in recent years or whether these strains have been circulating for a longer time, we retrospectively analyzed non-outbreak strains that occurred between 2008 and 2018 to identify frequent STs and CTs.

METHODS

In total, 120 VREfm isolates obtained from clinical and surveillance cultures from the years 2008, 2013, 2015, and 2018 were analyzed. Thirty isolates per year comprising the first 7-8 non-outbreak isolates of each quarter of the respective year were sequenced using whole genome sequencing. MLST and cgMLST were determined as well as resistance genes and virulence factors. Risk factors for VREfm ST117 were analyzed in a multivariable analysis with patient characteristics as possible confounders.

RESULTS

The percentage of VREfm of type ST117 increased from 17% in 2008 to 57% in 2018 (p = 0.012). In 2008, vanA genotype accounted for 80% of all ST117 isolates compared to 6% in 2018. VanB CT71 first appeared in 2018 and predominated over all other ST117 at 43% (p < 0.0001). The set of resistance genes (msrC, efmA, erm(B), dfrG, aac(6')-Ii, gyrA, parC and pbp5) and virulence factors (acm, esp, hylEfm, ecbA and sgrA) in CT71 was also found in other ST117 non-CT71 strains, mainly in CT36. The study population did not differ among the different calendar years analyzed in terms of age, gender, length of stay, or ward type (each p > 0.2).

CONCLUSION

This study revealed an increase in ST117 strains from 2008 to 2018, accompanied by a shift toward CT71 strains with the vanB genotype in 2018. We did not detect resistance or virulence traits in CT71 that could confer survival advantage compared to other CTs among ST117 strains. To date, it is not clear why ST117 and in particular strain type ST117 CT71 predominates over other strains.

A silent outbreak of vancomycin-resistant Enterococcus faecium in a neonatal intensive care unit

Objective

To describe the containment of a widespread silent outbreak of vancomycin-resistant Enterococcus faecium (VRE-fm) in the Tel-Aviv Medical Center (TASMC) neonatal intensive care unit (NICU).

Methods

Setting - an NICU, participants - 49 cases of VRE-fm-colonized neonatal inpatients.

Results

A newborn was transferred from the TASMC NICU to another hospital and screened positive for VRE-fm upon arrival. All TASMC NICU patients were then immediately screened for VRE and 21/38 newborns were identified as VRE carriers. Interventional measures were strictly enforced. By the end of the outbreak, 49 cases of VRE carriage had been identified. There were no VRE clinical infections. The source of the outbreak was not identified.

Conclusion

Our study highlights the importance of screening implementation in a NICU setting since this outbreak could have been prevented by active screening of all out-born transfer patients and by having adopted mandatory screening into the NICU’s routine procedures. Screening for multi-drug resistant organisms upon admission of all transferred patients to the NICU has been implemented.

Impact of improved observed hand hygiene on bloodstream infection rates in Ireland. A prospective segmented regression analysis, 2009-2016

Participation in European surveillance for bloodstream infection (BSI) commenced in Ireland in 1999 with all laboratories (n = 39) participating by 2014. Observational hand hygiene auditing (OHHA) was implemented in 2011. The aim of this study was to evaluate the impact of OHHA on hand hygiene compliance, alcohol hand rub (AHR) procurement and the incidence of sensitive and resistant Staphylococcus aureus and Enterococcus faecium and faecalis BSI. A prospective segmented regression analysis was performed to determine the temporal association between OHHA and outcomes. Observed hand hygiene improved from 74.7% (73.7-75.6) in 2011 to 90.8% (90.1-91.3) in 2016. AHR procurement increased from 20.1 l/1000 bed days used (BDU) in 2009 to 33.2 l/1000 BDU in 2016. A pre-intervention reduction of 2% per quarter in the ratio of methicillin sensitive Staphylococcus aureus BSI/BDU stabilized in the time period after the intervention (P < 0.01). The ratio of Methicillin resistant Staphylococcus aureus (MRSA) BSI/BDU was decreasing by 5% per quarter pre-intervention, this slowed to 2% per quarter post intervention, (P < 0.01). There was no significant change in the ratio of vancomycin sensitive (P = 0.49) or vancomycin resistant (P = 0.90) Enterococcus sp. BSI/BDU post intervention. This study shows national OHHA increased observed hand hygiene compliance and AHR procurement, however there was no associated reduction in BSI.

Automated Incubation and Digital Image Analysis of Chromogenic Media Using Copan WASPLab Enables Rapid Detection of Vancomycin-Resistant Enterococcus

Objective: The aim of the present study was to assess whether the WASPLab automation enables faster detection of vancomycin-resistant Enterococcus (VRE) on chromogenic VRE-specific plates by shortening the incubation time.

Methods: Ninety different VRE culture negative rectal ESwab specimens were spiked with various concentrations (ranging from 3 × 10² to 3 × 10⁷ CFU/ml) of 10 Enterococcus faecium strains (vancomycin MICs ranging from 32 to >256 mg/l), 3 E. faecium VanB strains (vancomycin MICs: 4, 8, and 16 mg/l), and 2 E. faecium VanB strains displaying vancomycin heteroresistance (vancomycin MICs: 64 and 96 mg/l).

Results: Besides the two strains exhibiting vancomycin heteroresistance, all the other 13 VRE strains included in this study were detected as early as 24 h on the WASPLab even if the inoculum was low (3 × 10³ CFU/ml). When the vancomycin MICs were high, all strains were detected as early as at 18 h. However, 30 h was a conservative time point for finalizing the analysis of chromogenic cultures.

Conclusion: These results suggested that the WASPLab automated incubation could allow decreasing the initial incubation time to 18 h, followed by an intermediate time at 24 h and a final incubation period of 30 h for VRE culture screening, to deliver rapid results without affecting the analytical sensitivity.

Elucidating vancomycin-resistant Enterococcus faecium outbreaks: the role of clonal spread and movement of mobile genetic elements

Background

Vancomycin-resistant Enterococcus faecium (VREfm) has emerged as a nosocomial pathogen worldwide. The dissemination of VREfm is due to both clonal spread and spread of mobile genetic elements (MGEs) such as transposons.

Objectives

We aimed to combine vanB-carrying transposon data with core-genome MLST (cgMLST) typing and epidemiological data to understand the pathways of transmission in nosocomial outbreaks.

Methods

Retrospectively, 36 VREfm isolates obtained from 34 patients from seven VREfm outbreak investigations in 2014 were analysed. Isolates were sequenced on a MiSeq and a MinION instrument. De novo assembly was performed in CLC Genomics Workbench and the hybrid assemblies were obtained through Unicycler v0.4.1. Ridom SeqSphere+ was used to extract MLST and cgMLST data. Detailed analysis of each transposon and their integration points was performed using the Artemis Comparison Tool (ACT) and multiple blast analyses.

Results

Four different vanB transposons were found among the isolates. cgMLST divided ST80 isolates into three cluster types (CTs); CT16, CT104 and CT106. ST117 isolates were divided into CT24, CT103 and CT105. Within VREfm isolates belonging to CT103, two different vanB transposons were found. In contrast, VREfm isolates belonging to CT104 and CT106 harboured an identical vanB transposon.

Conclusions

cgMLST provides a high discriminatory power for the epidemiological analysis of VREfm. However, additional transposon analysis is needed to detect horizontal gene transfer. Combining these two methods allows investigation of both clonal spread as well as the spread of MGEs. This leads to new insights and thereby better understanding of the complex transmission routes in VREfm outbreaks.

Carbapenem-Resistant Enterobacteriaceae Outbreak in a Medical Ward in Spain: Epidemiology, Control Strategy, and Importance of Environmental Disinfection

Introduction: Carbapenem-resistant Enterobacteriaceae (CRE) are a growing public health problem. We describe an outbreak by CRE and the measures to control it in a hospitalization unit in Spain. Methods: In June 2015, the system of prevention and control of CRE implemented in the hospital detected an increase in the incidence of patients with CRE in a mixed hospitalization facility (geriatrics, internal medicine, and pneumology), with the appearance of four related patients in 2 weeks, three of them being nosocomial cases. A multidisciplinary group was created and carried out: weekly screenings, general cleaning, four training sessions for personnel, two hand hygiene observation studies and environmental sampling. A higher incidence of new cases was detected in three adjoining rooms, in which environmental decontamination was performed with vaporized hydrogen peroxide. Results: In 5 months, a total of 18 cases were detected, 14 of them were nosocomial. Four different clones of Klebsiella pneumoniae OXA-48 were responsible for 83.3% of the cases. Adherence to hand hygiene increased from 36% to 85% after the training sessions. Seven percent of the environmental samples were positive for CRE in rooms with high incidence, moving to 0% after decontamination with hydrogen peroxide. Three patients died, one of them possibly associated with clinical infection due to CRE. Conclusions: Multidisciplinary information strategies, personnel training, and control of environmental reservoirs are effective to address outbreaks of CRE.

Novel Strategies for the Management of Vancomycin-Resistant Enterococcal Infections

PURPOSE OF REVIEW

Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens that commonly affect critically ill patients. VRE have a remarkable genetic plasticity allowing them to acquire genes associated with antimicrobial resistance. Therefore, the treatment of deep-seated infections due to VRE has become a challenge for the clinician. The purpose of this review is to assess the current and future strategies for the management of recalcitrant deep-seated VRE infections and efforts for infection control in the hospital setting.

RECENT FINDINGS

Preventing colonization and decolonization of multidrug-resistant bacteria are becoming the most promising novel strategies to control and eradicate VRE from the hospital environment. Fecal microbiota transplantation (FMT) has shown remarkable results on treating colonization and infection due to Clostridiodes difficille and VRE, as well as to recover the integrity of the gut microbiota under antibiotic pressure. Initial reports have shown the efficacy of FMT on reestablishing patient microbiota diversity in the gut and reducing the dominance of VRE in the gastrointestinal tract. In addition, the use of bacteriophages may be a promising strategy in eradicating VRE from the gut of patients. Until these strategies become widely available in the hospital setting, the implementation of infection control measures and stewardship programs are paramount for the control of this pathogen and each program should provide recommendations for the proper use of antibiotics and develop strategies that help to detect populations at risk of VRE colonization, prevent and control nosocomial transmission of VRE, and develop educational programs for all healthcare workers addressing the epidemiology of VRE and the potential impact of these pathogens on the cost and outcomes of patients. In terms of antibiotic strategies, daptomycin has become the standard of care for the management of deep-seated infections due to VRE. However, recent evidence indicates that the efficacy of this antibiotic is limited, and higher (10-12 mg/kg) doses and/or combination with β-lactams is needed for therapeutic success. Clinical data to support the best use of daptomycin against VRE are urgently needed. This review provides an overview of recent developments regarding the prevention, treatment, control, and eradication of VRE in the hospital setting. We aim to provide an update of the most recent therapeutic strategies to treat deep-seated infections due to VRE.

Appearance of vanD-positive Enterococcus faecium in a tertiary hospital in the Netherlands: prevalence of vanC and vanD in hospitalized patients

Vancomycin-resistant enterococci (VRE) can rapidly spread through hospitals. Therefore, our hospital employs a screening program whereby rectal swabs are screened for the presence of vanA and vanB, and only PCR-positive broths are cultured on VRE selection agar. Early November 2016, a clinical vanA-/vanB-negative VRE isolate was detected in a vanA/vanB-screening-negative patient, giving the possibility that an undetected VRE might be spreading within our hospital. Whole-genome-sequencing of the isolate showed that resistance was vanD-mediated and core genome multilocus sequence typing showed it was a rare type: ST17/CT154. To determine the prevalence of vanA/B/C/D-carrying enterococci, we designed a real-time PCR for vanC1/2/3 and vanD and screened rectal swabs from 360 patients. vanD was found in 27.8% of the patients, yet culture demonstrated only E. faecium from vanA-positive broths and E. gallinarum from vanC1-positive broths. No vanD-positive VRE were found, limiting the possibility of nosocomial spread of this VRE. Moreover, the high prevalence of non-VRE vanD in rectal swabs makes it unfeasible to include the vanD PCR in our VRE screening. However, having validated the vanC1/2/3 and vanD PCRs allows us to rapidly check future vanA/B-negative VRE for the presence of vanC and vanD genes.

Antimicrobial Resistance, Virulence Determinants, and Biofilm Formation of Enterococcus Species From Ready-to-Eat Seafood

Enterococcus species form an important population of commensal bacteria and have been reported to possess numerous virulence factors considered significantly important in exacerbating diseases caused by them. The present study was designed to characterize antibiotic-resistant and virulent enterococci from ready-to-eat (RTE) seafood. A total of 720 RTE shrimp samples comprising sauced shrimp (n = 288), boiled shrimp (n = 216), and smoked shrimp (n = 216) obtained from open markets in Delta State, Nigeria, were assessed. Standard classical methods and polymerase chain reaction (PCR) were used in identifying the Enterococcus species. Potential virulence factors (β-hemolysis, gelatinase activity, S-layer, and biofilm formation) were assessed using standard procedures. The antibiotic susceptibility profile of the identified enterococci isolates was assayed using the Kirby–Bauer disc diffusion method. PCR was further used to screen selected antibiotic resistance and virulence genes. Prevalence of Enterococcus species from shrimp varieties is as follows: sauced, 26 (9.03%); boiled, 6 (2.78%); and smoked, 27 (12.50%), with an overall prevalence of 59 (8.19%) based on the occurrence of black hallow colonies after incubation. Enterococcus species detected include E. faecalis, 17 (28.8%); E. faecium, 29 (49.2%); E. gallinarum, 6 (10.2%); E. casseliflavus, 2 (3.4%); E. hirae, 3 (5.1%); and E. durans, 2 (3.4%). Biofilm occurrence among the shrimp varieties is as follows: 19/26 (73.1%) for sauced shrimps, 5/6 (83.3%) for boiled shrimps, and 16/27 (59.3%) for smoked shrimps. The phenotypic expression of the enterococci virulence revealed the following: S-layer, 59 (100%); gelatinase production, 19 (32.2%); and β-hemolysis, 21 (35.6%). An average of 3–11 virulence genes were detected in the Enterococcus species. The resistance profile of Enterococcus species is as follows: erythromycin, 29 (49.2%); vancomycin, 22 (37.3%); and tetracycline, 27 (45.8%). The frequency of occurrence of antibiotic resistance genes from the phenotypic resistant enterococci isolates to the macrolide, glycopeptide, and tetracycline antibiotics is as follows: ermA, 13/29 (44.8%); vanA, 14/22 (63.6%); tetA, 14/27 (51.9%); tetM, 15/27 (55.6%); ermB, 4/29 (13.8%); and vanB, 5/22 (22.7%). Findings from this study reveal the antibiotic resistance of enterococci strains of such species as E. durans, E. casseliflavus, E. gallinarum, and E. hirae. This study further revealed that RTE food products are reservoirs of potential virulent enterococci with antibiotic-resistant capabilities. This provides useful data for risk assessment and indicates that these foods may present a potential public health risk to consumers.

Vancomycin-resistant enterococci (VRE): a reason to isolate?

In recent years, an increase in invasive VRE infections has been reported worldwide, including Germany. The most common gene encoding resistance to glycopeptides is VanA, but predominant VanB clones are emerging. Although neither the incidence rates nor the exact routes of nosocomial transmission of VRE are well established, screening and strict infection control measures, e.g. single room contact isolation, use of personal protective clothing by hospital staff and intensified surface disinfection for colonized individuals, are implemented in many hospitals. At the same time, the impact of VRE infection on mortality remains unclear, with current evidence being weak and contradictory. In this short review, we aim to give an overview on the current basis of evidence on the clinical effectiveness of infection control measures intended to prevent transmission of VRE and to put these findings into a larger perspective that takes further factors, e.g. VRE-associated mortality and impact on patient care, into account.