Outbreak Of Vancomycin-resistant Enterococci Research Articles

Prevention of possible vancomycin resistant enterococcus outbreak caused by infants transferred due to earthquake-trauma

Infection control measures are disrupted due to the large number of patients admitted in a very short time, in the early post-earthquake period. Inter-hospital or intra-hospital transfers can cause the spread of resistant bacteria. We reported the possible outbreak and its prevention caused by vancomycin-resistant enterococcus (VRE) strains carried by infants transferred from another unit to our neonatal intensive care unit after the earthquake. Screening cultures (rectal swab) were obtained from infants on admission and patients were kept in contact isolation. We studied the clonal analysis of VRE strains isolated from patients by Pulse Field Gel Electroforesis.

Antibiotic susceptibility and genome analysis of Enterococcus species isolated from inpatients in one hospital with no apparent outbreak of vancomycin-resistant Enterococcus in Japan.

To prevent nosocomial infection, it is important to screen for potential vancomycin-resistant Enterococcus (VRE) among patients. In this study, we analyzed enterococcal isolates from inpatients in one hospital without any apparent outbreak of VRE. Enterococcal isolates were collected from inpatients at Hiroshima University Hospital from April 1to June 30, 2021 using selective medium for Enterococci. Multilocus sequence typing, antimicrobial susceptibility testing, and whole-genome sequencing were performed. A total of 164 isolates, includingEnterococcus faecium (41 isolates), Enterococcus faecalis (80 isolates), Enterococcus raffinosus (11 isolates), Enterococcus casseliflavus (nine isolates), Enterococcus avium (12 isolates), Enterococcus lactis (eight isolates), Enterococcus gallinarum (two isolates), and Enterococcus malodoratus (one isolate), were analyzed. We found one vanA-positive E. faecium, which was already informed when the patient was transferred to the hospital, ninevanC-positive E. casseliflavus, and twovanC-positive E. gallinarum. E. faecium isolates showed resistance to ampicillin (95.1%), imipenem (95.1%), and levofloxacin (87.8%), and E. faecalis isolates showed resistance to minocycline (49.4%). Ampicillin- and levofloxacin-resistant E. faecium had multiple mutations in penicillin-binding protein 5 (PBP5) (39/39 isolates) and ParC/GyrA (21/36 isolates), respectively. E. raffinosus showed resistance to ampicillin (81.8%), imipenem (45.5%), and levofloxacin (45.5%), and E. lactis showed resistance to ampicillin (37.5%) and imipenem (50.0%). The linezolid resistance genes optrA and cfr(B) were found only in one isolate of E. faecalis and E. raffinosus, respectively. This study, showing the status of enterococci infection in hospitalized patients, is one of the important information when considering nosocomial infection control of VRE.

Genomic analysis of inter-hospital transmission of vancomycin-resistant Enterococcus faecium sequence type 80 isolated during an outbreak in Hiroshima, Japan.

Outbreaks caused by vancomycin-resistant enterococci that transcend jurisdictional boundaries are occurring worldwide. This study focused on a vancomycin-resistant enterococcus outbreak that occurred between 2018 and 2021 across two cities in Hiroshima, Japan. The study involved genetic and phylogenetic analyses using whole-genome sequencing of 103 isolates of vancomycin-resistant enterococci to identify the source and transmission routes of the outbreak. Phylogenetic analysis was performed using core genome multilocus sequence typing and core single-nucleotide polymorphisms; infection routes between hospitals were inferred using BadTrIP. The outbreak was caused by Enterococcus faecium sequence type (ST) 80 carrying the vanA plasmid, which was derived from strain A10290 isolated in India. Of the 103 isolates, 93 were E. faecium ST80 transmitted across hospitals. The circular vanA plasmid of the Hiroshima isolates was similar to the vanA plasmid of strain A10290 and transferred from E. faecium ST80 to other STs of E. faecium and other Enterococcus species by conjugation. The inferred transmission routes across hospitals suggest the existence of a central hospital serving as a hub, propagating vancomycin-resistant enterococci to multiple hospitals. Our study highlights the importance of early intervention at the key central hospital to prevent the spread of the infection to small medical facilities, such as nursing homes, with limited medical resources and a high number of vulnerable individuals.

An Outbreak of Vancomycin-Resistant Enterococci in a City Hospital Intensive Care Unit: Molecular Characterization of Resistance.

Background and Objectives: Vancomisin-resistant Enterococci (VRE), is a resistant microorganism that colonizes and causes infections in hospitalized patients. The aim of this study was to show the spread of vancomycin-resistant Enterococcus faecium (VREfm) step-by-step in all intensive care units, which started with the growth of VREfm on 2 December 2021 in the blood culture of a patient hospitalized in the anesthesia intensive care unit of our hospital and was found to have reached epidemic size in the surveys. Materials and Methods: Rectal swab samples were taken from all patients hospitalized in intensive care units, VRE colonization was determined, the VanA and VanB resistance genes associated with the vancomycin resistance of VREfm isolates were determined by PCR method, and clonal association analysis was performed by Arbitrarily Primed-PCR (AP-PCR) and PFGE (pulsed-field gel electrophoresis). Results: In our study, VRE were detected in 61 of 2601 rectal swab samples. In total, fifty-four (85.52%) of the VRE isolates were Enterococcus faecium, three (4.91%) was Enterococcus faecalis, three (4.91%) was Enterococcus gallinorum, and one (1.63%) was Enterococcus casseliflavus. It was determined that all of the 54 VREfm isolates, which were the most detected among all VRE isolates, carried the vanA gene. In the clonal association analysis of the isolates by AP-PCR and PFGE methods, it was found that they had 12 different genotypes, 48 of them were included in any cluster, the clustering rate was 88.8%, and the largest cluster was the genotype 1 cluster, with 36 isolates. Of the 54 patients with VREfm isolated recently, 18.51 percent of the clinical samples were isolated before the survey, and 9.25% were isolated after the survey. It was determined that 100% of VREfm isolates were resistant to ampicillin, levofloxacin, ciprofloxacin, high-level gentamicin, trimethoprimsulfamethoxazole, and teicoplanin, 7.4% to tigecycline, and 1.85% to linezolid. Conclusions: In our study, in the clonal association analysis performed by isolating VREfm in rectal swab samples, it was found that 88.8% of the samples were indistinguishably similar, and that the increase in the number of VREfm infections after the index case in our hospital was associated with the epidemic. VREfm infections cause long-term hospitalization, costs and also deaths, which shows the seriousness of the event, and the importance of the combination of epidemiological and molecular analysis in epidemic research.

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

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. 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. 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). 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.

Costs of two vancomycin-resistant enterococci outbreaks in an academic hospital.

In early 2017, the University Medical Center Groningen, the Netherlands, had an outbreak of 2 strains of vancomycin-resistant enterococci (VRE) that spread to various wards. In the summer of 2018, the hospital was again hit by a VRE outbreak, which was detected and controlled early. However, during both outbreaks, fewer patients were admitted to the hospital and various costs were incurred. We quantified the costs of the 2017 and 2018 VRE outbreaks. Using data from various sources in the hospital and interviews, we identified and quantified the costs of the 2 outbreaks, resulting from tests, closed beds (opportunity costs), cleaning, additional personnel, and patient isolation. The University Medical Center Groningen, an academic hospital in the Netherlands. The total costs associated with the 2017 outbreak were estimated to be €335,278 (US $356,826); the total costs associated with the 2018 outbreak were estimated at €149,025 (US $158,602). The main drivers of the costs were the opportunity costs due to the reduction in admitted patients, testing costs, and cleaning costs. Although the second outbreak was considerably shorter, the costs per day were similar to those of the first outbreak. Major investments are associated with the VRE control measures, and an outbreak of VRE can lead to considerable costs for a hospital. Aggressively screening and isolating patients who may be involved in an outbreak of VRE may reduce the overall costs and improve the continuity of care within the hospital.

Vancomycin-resistant Enterococcus outbreak in a pre- and post-cardiothoracic transplant population: Impact of discontinuing multidrug-resistant organism surveillance during the coronavirus disease 2019 pandemic.

Many institutions suspended surveillance and contact precautions for multidrug-resistant organisms (MDROs) at the outset of the coronavirus disease 2019 (COVID-19) pandemic due to a lack of resources. Once our institution reinstated surveillance in September 2020, a vancomycin-resistant Enterococcus (VRE) faecium outbreak was detected in the cardiothoracic transplant units, a population in which we had not previously detected outbreaks. An outbreak investigation was conducted using pulsed-field gel electrophoresis for strain typing and electronic medical record review to determine the clinical characteristics of involved patients. The infection prevention (IP) team convened a multidisciplinary process improvement team comprised of IP, cardiothoracic transplant nursing and medical leadership, environmental services, and the microbiology laboratory. Between December 2020 and March 2021, the outbreak involved thirteen patients in the cardiothoracic transplant units, four index cases, and nine transmissions. Of the 13, seven (54%) were on the transplant service, including heart and lung transplant recipients, patients with ventricular assist devices, and a patient on extracorporeal membrane oxygenation as a bridge to lung transplantation. Four of 13 (31%) developed a clinical infection. Cardiothoracic surgery/transplant patients may have a similar risk for VRE-associated morbidity as abdominal solid organ transplant and stem cell transplant patients, highlighting the need for aggressive outbreak management when VRE transmission is detected. Our experience demonstrates an unintended consequence of discontinuing MDRO surveillance in this population and highlights a need for education, monitoring, and reinforcement of foundational infection prevention measures to ensure optimal outcomes.

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.

A Bayesian spatiotemporal model for prevalence estimation of a VRE outbreak in a tertiary care hospital

There was a nosocomial outbreak of vancomycin-resistant enterococci (VRE) at the hospital between 1st January 2018 and 31st July 2020. The goals of this study were to describe weekly prevalence, and to identify possible effects of the introduction of selected infection control measures. A room-centric analysis of 12 floors (243 rooms) of the main hospital building was undertaken, including data on 37,558 patients over 22,072 person-weeks for the first 2 years of the outbreak (2018-2019). Poisson Bayesian hierarchical models were fitted to estimate prevalence per room and per week, including both spatial and temporal random effects terms. Exploratory data analysis revealed significant variability in prevalence between departments and floors, along with sporadic spatial and temporal clustering during colonization 'flare-ups'. The oncology department experienced slightly higher prevalence over the 104-week study period [adjusted prevalence ratio (aPR) 4.8, 95% confidence interval (CI) 2.6-8.9; P<0.001; compared with general medicine], as did both the cardiac surgery (aPR 3.8, 95% CI 2.0-7.3; P<0.001) and abdominal surgery (aPR 3.7, 95% CI 1.8-7.6; P<0.001) departments. Estimated peak prevalence was reached in July 2018, at which point a number of new infection control measures (including the daily disinfection of rooms and room cleaning with ultraviolet light upon patient discharge) were introduced that resulted in decreasing prevalence (aPR 0.89 per week, 95% CI 0.87-0.91; P<0.001). Relatively straightforward but personnel-intensive cleaning with disinfectants and ultraviolet light provided tangible benefits in getting the outbreak under control. Despite additional complexity, Bayesian hierarchical models provide a more flexible platform to study transmission dynamics.

794. The Role of the Environment in Healthcare-associated Transmission of Vancomycin Resistant Enterococcus: A Proof of Concept Study

BackgroundTransmission of Vancomycin Resistant Enterococcus (VRE) from environment to patient and patient to patient can both occur in healthcare settings. Due to the COVID-19 pandemic, a cohort of exposed patients on an inpatient unit with an extensive VRE outbreak needed to switch physical locations with a non-exposed patient population. By comparing outcomes of both cohorts, we aimed to determine the role of the physical environment (both direct and indirect contact) as compared to the patient population, in ongoing VRE transmission.MethodsFrom 10 March to 21 April 2021, 41 new nosocomial acquisitions of VRE were detected as part of a VRE outbreak on a 34-bed acute care unit. Prior to the switch of units, extensive cleaning of the unit was conducted including electrostatic adjuncts to standard cleaning and environmental swabbing for VRE yielded no positive surfaces. The exposed cohort included 3 of 30 patients with VRE while the non-exposed cohort had 0 of 28 VRE positive patients based on prevalence testing on 21 April 2021. Following the physical relocation of both cohorts on 22 April, 2021, prospective VRE screening was performed on both units for one month including on admission, discharge and weekly prevalence screening. Hand hygiene compliance rates on both units was measured using group electronic monitoring. ResultsFigure 1 depicts the timeline and number of VRE cases before and after the unit switch. Following relocation of the VRE exposed cohort to the new unit, no further VRE transmission was detected (0/235 VRE screens; 0 VRE cases per 1000 patient days). Conversely, there were new VRE transmissions (3/99 VRE screens, 5 VRE cases per 1000 patient days) in the non-exposed cohort. When the units resumed their original location, one additional case of VRE was identified in the exposed cohort upon return to their original location. These transmissions occurred despite HH compliance of 94% (141,610/150,706) during the entire study period on the outbreak unit, which was consistently higher than on the non-outbreak unit (141,589/227,136, 62%).Figure 1. ConclusionThe environmental reservoir for VRE may be more important in transmission than the patient reservoir. These findings underscore the importance of environmental cleaning to contain VRE outbreaks. Disclosures All Authors: No reported disclosures

795. A Bayesian Spatial-temporal Modelling Approach for Prevalence Estimation of a VRE Outbreak in a Tertiary Care Hospital

BackgroundThere was a nosocomial outbreak of vancomycin-resistant enterococci (VRE) in our hospital group from 2018-19. The goals of the study were to describe the prevalence trajectory and explore risk factors associated with putative room colonization during the outbreak. MethodsWe performed a room centric analysis of 12 floors (floors F to R, 264 rooms) of the main bed tower of the hospital, including data on 37’458 patients (23’050 person weeks) over the 104 week period. Patients were assumed to be colonized in the week prior to their first positive test, and thereafter throughout the remainder of their stay until discharge. Poisson Bayesian Hierarchical models were fitted to estimate prevalence per room, including both spatial (conditional autoregressive) and temporal (random walk) random effects terms. Model M1 estimated prevalence for each floor and then used meta-analysis to combine the estimates, whereas model M2 estimated prevalence for “all-floors” simultaneously.ResultsThe oncology department, where the outbreak was thought to have started, experienced slightly higher prevalence (floors O and R; adjusted incidence rate ratio (aIRR) 4.8 [2.6, 8.9], p< 0.001; reference is general medicine; see Figure Panel A), as did both the cardiac surgery (floors G, N, O; aIRR 3.8 [2.0, 7.3], p< 0.001) and abdominal surgery departments (floors H and Q; 3.7 [1.8, 7.6], p< 0.001). There was no discernible difference in prevalence between floors with single and multiple department occupancy. Furthermore, departments spread across multiple floors had similar prevalence on all constituent floors – perhaps indicating transmission by people or devices moving between floors.The “single floor meta-analysis” model (M1) more closely followed the estimated trajectory for the crude prevalence, whereas the “all floors” model (M2) dampened the amplitude of the peaks somewhat, but better estimated periods of low prevalence (Figure Panel B).Figure: Estimates from the Bayesian Hierarchical Models Panel A. Random effect prevalence estimates for each floor (from model M2). Panel B. Crude prevalence (black) and estimates from the “single floor meta-analysis” approach (M1, dashed red) with 95% credible intervals shaded (shaded red), and “all-floors” model (M2, blue ). ConclusionWe applied a room centric approach that took into account spatial and temporal dependencies apparent in the nosocomial VRE outbreak. Despite additional complexity, Bayesian Hierarchical Models provide a more flexible platform for studying transmission dynamics and performing hypothesis testing, compared to more traditional methods.Disclosures All Authors: No reported disclosures

Transmission dynamics of a linear vanA-plasmid during a nosocomial multiclonal outbreak of vancomycin-resistant enterococci in a non-endemic area, Japan

The spread of vancomycin-resistant enterococci (VRE) is a major threat in nosocomial settings. A large-scale multiclonal VRE outbreak has rarely been reported in Japan due to low VRE prevalence. We evaluated the transmission of vancomycin resistance in a multiclonal VRE outbreak, conducted biological and genomic analyses of VRE isolates, and assessed the implemented infection control measures. In total, 149 patients harboring VanA-type VRE were identified from April 2017 to October 2019, with 153 vancomycin-resistant Enterococcus faecium isolated being grouped into 31 pulsotypes using pulsed-field gel electrophoresis, wherein six sequence types belonged to clonal complex 17. Epidemic clones varied throughout the outbreak; however, they all carried vanA-plasmids (pIHVA). pIHVA is a linear plasmid, carrying a unique structural Tn1546 containing vanA; it moves between different Enterococcus spp. by genetic rearrangements. VRE infection incidence among patients in the “hot spot” ward correlated with the local VRE colonization prevalence. Local prevalence also correlated with vancomycin usage in the ward. Transmission of a novel transferrable vanA-plasmid among Enterococcus spp. resulted in genomic diversity in VRE in a non-endemic setting. The prevalence of VRE colonization and vancomycin usage at the ward level may serve as VRE cross-transmission indicators in non-intensive care units for outbreak control.

Epidemiologic Investigation of an Outbreak of Vancomycin-resistant Enterococcus in a Tertiary Care Neonatal Intensive Care Unit

<h3>Background</h3> Increasingly prevalent vancomycin-resistant Enterococcus (VRE) amongst neonatal and pediatric patients may cause outbreaks and result in infections associated with significant morbidity. We describe a VRE outbreak in our 52-bed neonatal intensive care unit (NICU), its control methods, and recommendations for prevention. <h3>Methods</h3> This outbreak was declared on August 7, 2018, upon discovery of two new cases one week after the index case identification in our NICU. Outbreak management strategies implemented included contact precautions, weekly unit VRE screening, optimization of hand hygiene, enhanced environmental cleaning and disinfection, cohorting of cases and healthcare worker (HCW) and parent education. Typing by pulsed-field gel electrophoresis (PFGE) was performed for all outbreak strains and compared to VRE strains from the adjoining adult hospital. <h3>Results</h3> Six VRE cases occurred during the 4-week-long outbreak: 5 were colonizations and 1 patient eventually developed a central line-associated bloodstream infection. All colonized neonates had been physically located in the same area of the NICU at some point prior to becoming colonized. Hand hygiene compliance was 62% at the start of the outbreak. PFGE typing confirmed horizontal transmission of a single strain (pulsovar E) which was not related to other typed strains from the adult hospital. The source of the outbreak was not identified. None of the mothers of the colonized patients had been screened for VRE antenatally. In total, 348 VRE screening tests were performed. After three consecutive weeks without new cases, the outbreak was declared over. The need for HCW and parent education on VRE prevention and control was identified. <h3>Conclusions</h3> A multi-faceted approach to controlling a VRE outbreak is key, with emphasis on hand hygiene and HCW and parent education, especially as VRE prevalence in pediatric centers is low. In addition, antenatal maternal screening for VRE could be beneficial to identify neonates at risk for colonization.

Emergence of vanA-Type Vancomycin-Resistant Enterococcus faecium ST 78 Strain with a rep2-Type Plasmid Carrying a Tn1546-Like Element Isolated from a Urinary Tract Infection in China.

PurposeThe emergence of vancomycin-resistant enterococci (VRE) dramatically narrows therapeutic options. Although the prevalence of VRE in China has maintained a low level, VRE outbreaks have been reported in some tertiary hospitals in the developed areas of China. The clonal background of vanA-positive Enterococcus faecium strains has not been well characterized in China. Here, we report the whole-genome sequence of a vanA-type vancomycin-resistant E. faecium belonging to sequence type (ST) 78 isolated from a urinary tract infection in China.Patients and MethodsA vancomycin-resistant E. faecium was isolated from a 66-year-old male patient diagnosed with brainstem hemorrhage. Antibiotic susceptibility assays were performed according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Complete genome sequencing was performed using both the HiSeqTM 4000 platform and the MinION platform. Plasmid, genomic and phylogenetic relationship analysis were further performed.ResultsE. faecium VRE1 was resistant to all antimicrobials tested except for tetracyclines and oxazolidinones. The whole genome of E. faecium VRE1 was composed of one chromosomal DNA and four plasmids. Two virulence genes and five antimicrobial resistance genes were identified. In silico multilocus sequence typing (MLST) showed that it belonged to ST78 (clonal complex CC17), a well-known epidemic clone that is widespread in Europe and the United States. Three antimicrobial resistance genes, including aminoglycoside resistance genes ant(6)-Ia and aph(3ʹ)-III; and glycopeptide resistance gene vanA, were located on a rep2-type plasmid carrying a Tn1546-like element that has not been reported. The most closely related strain harboring a similar plasmid backbone was recovered from fodder sample in China that differed by 178 cgMLST loci.ConclusionOur study characterizes the genomic feature of a vancomycin-resistant E. faecium ST78 strain harboring a vanA-carrying plasmid in China. The ST78 clonal group possessed the potential to emerge as a successful vanA-carrying epidemic lineage in China.

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

PurposeVancomycin-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.MethodsIdentification 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).ResultsAll 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.ConclusionVRE 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.

Risk factors for vancomycin-resistant enterococcus acquisition during a large outbreak in patients aged 65\u2009years and older

BackgroundIn the context of an aging population, identifying risk factors for Vancomycin-resistant enterococci (VRE), specific to older people, is important. However, if age is a known risk factor for VRE infection, a limited number of studies have focused on older patients. This study aimed to identify potential risk factors for VRE acquisition in a population aged 65 years and older, during a large VRE outbreak that occurred in a teaching hospital in Lyon, France, from December 2013 to July 2014.MethodsThe present retrospective, multi-center, descriptive, and analytical study used part of a previous cohort, and included only a sub-group of patients aged 65 years and older. The analysis of the factors included in the original study was completed with factors more specific to geriatric patients. Inclusion criteria were patients aged 65 years and older, in contact with a VRE index patient. Patients were screened by rectal swabs. Univariate and multivariate logistic regression analyses were performed.ResultsA total of 180 VRE contacts were included and 18 patients became carriers. Multivariate analysis showed that risk factors for VRE acquisition in older people included major contact type (RR: 5.31, 95%CI [1.33; 21.19]), number of antibiotics used (RR: 1.36, 95%CI [1.04; 1.76]), a score of McCabe = 2 (RR: 116.39, 95%CI [5.52; 2455.98]), ethylism (RR: 5.50, 95%CI [1.49; 20.25]), and dementia (RR: 7.50, 95%CI [1.89; 29.80]).ConclusionsThis study was able to demonstrate risk factors for VRE acquisition in older people. These risk factors should be taken into account when in the presence of older people in a VRE infected unit.

Do pneumatic tube transport systems transmit potential pathogens? A hygienic risk assessment in a university hospital

Prompted by an outbreak of vancomycin-resistant enterococci (VRE) in a medical facility, this study examined a pneumatic tube transport system (PTS) as a potential transmission channel. Samples from the receiving station and entry racks were gathered via smear technique. Sponges used for PTS decontamination were soaked with 0.89% NaCl and transported through the channel. Micro-organisms were recovered from the tubes and cleaning sponges using a wash-away technique. Air sampling was performed at the receiving station in order to detect any airborne contamination. Tubes were artificially inoculated with Escherichia coli K12 NCTC 10538 and Staphylococcus epidermidis DSM 20044 and sent through the PTS to investigate channel contamination. No pathogens were detected in effluent air from the PTS or in tubes during routine operation. Entry racks for the test tubes were contaminated with coagulase-negative staphylococci (CNS), aerobic bacilli, moulds and vancomycin-susceptible Enterococcus faecium. E.coli proved to be unsuitable for detecting bacterial transmission by the PTS due to low persistence, but S.epidermidis was more resilient. After sending contaminated test tubes through the PTS, levels of S.epidermidis only decreased marginally. Subsequently, sponges soaked with disinfectant solution were put through the system and these eliminated S.epidermidis completely from the first attempt. Routine hygienic maintenance of the PTS makes pathogen transmission highly unlikely, although entry racks should be disinfected regularly. Any involvement of the PTS in the VRE outbreak at the study institution was unlikely.

Comparison of whole-genome sequencing and pulsed field gel electrophoresis for characterizing relationships in Mannheimia haemolytica

It has long been presumed that cattle developing BRD tend to become sick from their own native strains of Mannheimia haemolytica. Previous work by others has demonstrated that the diversity of Mannheimia haemolytica, as evaluated by PFGE, within a pen of cattle remains high during BRD outbreaks. Prior to the development of whole genome sequencing (WGS), pulsed field gel electrophoresis (PFGE) had been considered the gold standard for characterizing outbreaks of bacterial disease. Recently, many studies from the human literature have raised question regarding the accuracy of PFGE as WGS has become more widely implemented. Studies investigating Acinetobacter baumanii, Clostridium difficile, and vancomycin resistant Enterococci outbreaks in hospitals have shown WGS to have superior discernment and more accurately classify strains when compared to PFGE. Considering the superiority of WGS in characterizing outbreaks in all of these species, if may be that relationships inferred in Mannheimia haemolytica based on PFGE could be inaccurate. It is therefore our goal to compare the discernment ability of PFGE and WGS for Mannheimia haemolytica isolates collected from beef cattle.

Bayesian reconstruction of a vancomycin-resistant Enterococcus transmission route using epidemiologic data and genomic variants from whole genome sequencing

Outbreaks of vancomycin-resistant enterococcus (VRE) are a serious problem in hospitals. Inferring the transmission route is an important factor to institute appropriate infection control measures; however, the methodology has not been fully established. To reconstruct and evaluate the transmission model using sequence variants extracted from whole genome sequencing (WGS) data and epidemiological information from patients involved in a VRE outbreak. During a VRE outbreak in our hospital, 23 samples were collected from patients and environmental surfaces and analysed using WGS. By combining genome alignment information with patient epidemiological data, the VRE transmission route was reconstructed using a Bayesian approach. With the transmission model, evaluation and further analyses were performed to identify risk factors that contributed to the outbreak. All VREs were identified as Enterococcus faecium belonging to sequence type 17, which consisted of two VRE genotypes: vanA (N= 8, including one environmental sample) and vanB (N= 15). The reconstruction model using the Bayesian approach showed the transmission direction with posterior probability and revealed transmission through an environmental surface. In addition, some cases acting as VRE spreaders were identified, which can interfere with appropriate infection control. Vancomycin administration was identified as a significant risk factor for spreaders. A Bayesian approach for transmission route reconstruction using epidemiologic data and genomic variants from WGS can be applied in actual VRE outbreaks. This may contribute to the design and implementation of effective infection control measures.

Molecular analysis and epidemiological typing of Vancomycin-resistant Enterococcus outbreak strains

Outbreaks of multidrug resistant bacteria including vancomycin-resistant enterococci (VRE) in healthcare institutions are increasing in Norway, despite a low level of resistance compared to other European countries. In this study, we describe epidemiological relatedness of vancomycin-resistant Enterococcus faecium isolated during an outbreak at a Norwegian hospital in 2012–2013. During the outbreak, 9454 fecal samples were screened for VRE by culture and/or PCR. Isolates from 86 patients carrying the vanA resistance gene were characterized using pulsed-field gel electrophoresis (PFGE), MALDI-TOF mass spectrometry and single nucleotide polymorphism typing. PFGE revealed two main clusters, the first comprised 56 isolates related to an initial outbreak strain, and the second comprised 21 isolates originating from a later introduced strain, together causing two partly overlapping outbreaks. Nine isolates, including the index case were not related to the two outbreak clusters. In conclusion, the epidemiological analyses show that the outbreak was discovered by coincidence, and that infection control measures were successful. All typing methods identified the two outbreak clusters, and the experiment congruence between the MALDI-TOF and the PFGE clustering was 63.2%, with a strong correlation (r = 72.4%). Despite lower resolution compared to PFGE, MALDI-TOF may provide an efficient mean for real-time monitoring spread of infection.