How long do nosocomial pathogens persist on inanimate surfaces? A scoping review

Healthcare hygiene plays a crucial role in the prevention of healthcare-associated infections. Patients admitted to a room where the previous occupant had a multi-drug-resistant bacterial infection are at an increased risk of colonization and infection with the same organism. A 2006 systematic review by Kramer et al. found that certain pathogens can survive for months on dry surfaces. The aim of this review is to update Kramer et al.'s previous review and provide contemporary data on the survival of pathogens relevant to the healthcare environment. We systematically searched Ovid MEDLINE, CINAHL and Scopus databases for studies that described the survival time of common nosocomial pathogens in the environment. Pathogens included in the review were bacterial, viral, and fungal. Studies were independently screened against predetermined inclusion/exclusion criteria by two researchers. Conflicts were resolved by one of two senior researchers. A spreadsheet was developed for the data extraction. The search identified 1736 studies. Following removal of duplicates and application of the search criteria, the synthesis of results from 62 included studies were included. 117 organisms were reported. The longest surviving organism reported was Klebsiella pneumoniae which was found to have persisted for 600 days. Common pathogens of concern to infection prevention and control, can survive or persist on inanimate surfaces for months. This data supports the need for a risk-based approach to cleaning and disinfection practices, accompanied by appropriate training, audit and feedback which are proven to be effective when adopted in a 'bundle' approach.

Using Genomics To Investigate an Outbreak of Vancomycin-Resistant Enterococcus faecium ST78 at a Large Tertiary Hospital in Queensland

To investigate an outbreak of vancomycin-resistant Enterococcus faecium (VREfm) sequence type 78 (ST78) in a large tertiary Australian hospital. A collection of 63 VREfm ST78 isolates, identified during a routine genomic surveillance program, were subjected to genomic epidemiological analysis based on whole-genome sequencing (WGS) data. The population structure was reconstructed using phylogenetic analysis, and a collection of publicly available VREfm ST78 genomes were used to provide global context. Core genome single nucleotide polymorphism (SNP) distances and available clinical metadata were used to characterize outbreak clusters and reconstruct transmission events. In silico genotyping confirmed that all study isolates were vanB-type VREfm carrying virulence characteristics of the hospital-associated E. faecium. Phylogenetic analysis identified two distinct phylogenetic clades, only one of which was responsible for a hospital outbreak. Four outbreak subtypes could be defined with examples of recent transmissions. Inference on transmission trees suggested complex transmission routes with unknown environmental reservoirs mediating the outbreak. WGS-based cluster analysis with publicly available genomes identified closely related Australian ST78 and ST203 isolates, highlighting the capacity for WGS to resolve complex clonal relationships between the VREfm lineages. Whole genome-based analysis has provided a high-resolution description of an outbreak of vanB-type VREfm ST78 in a Queensland hospital. Combined routine genomic surveillance and epidemiological analysis have facilitated better understanding of the local epidemiology of this endemic strain, providing valuable insight for better targeted control of VREfm. IMPORTANCE Vancomycin-resistant Enterococcus faecium (VREfm) is a leading cause of health care-associated infections (HAIs) globally. In Australia, the spread of hospital-adapted VREfm is largely driven by a single clonal group (clonal complex [CC]), CC17, to which the lineage ST78 belongs. While implementing a genomic surveillance program in Queensland, we observed increased incidence of ST78 colonizations and infections among patients. Here, we demonstrate the use of real-time genomic surveillance as a tool to support and enhance infection control (IC) practices. Our results show that real-time whole-genome sequencing (WGS) can efficiently disrupt outbreaks by identifying transmission routes that in turn can be targeted using resource-limited interventions. Additionally, we demonstrate that by placing local outbreaks in a global context, high-risk clones can be identified and targeted prior to them becoming established within clinical environments. Finally, the persistence of these organism within the hospital highlights the need for routine genomic surveillance as a management tool to control VRE transmission.

Detection of Vancomycin-Resistant Enterococcus faecium Endocarditis After Clearance of Vancomycin-Sensitive Enterococcus faecium Bacteremia

Vancomycin-resistant enterococcal (VRE) bacteremia is associated with higher mortality rates and longer hospitalizations than vancomycin-sensitive enterococcal (VSE) bacteremia. A 67-year-old man with a right psoas abscess and pacemaker-associated tricuspid valve endocarditis in September 2020 grew VSE Enterococcus faecium from blood cultures that cleared after administration of intravenous vancomycin and gentamicin. Subsequently, he underwent tricuspid valve repair, pacemaker removal, and partial lead extraction. Valve and postoperative blood cultures grew VRE E. faecium, which cleared after administration of intravenous daptomycin. One VSE and two VRE isolates were collected and sequenced. All isolates belonged to E. faecium multilocus sequence type ST17 and were closely related, having <20 mutations in pairwise genome comparisons. Vancomycin resistance was due to the acquisition of a plasmid-encoded VanA operon. None of the isolates encoded the virulence factors asa1, gelE, cylA, or hyl; all encoded a homologue of efaAfm. VSE E. faecium, but not VRE E. faecium isolates, encoded a glucose transporter gene mutation. Two VRE E. faecium isolates formed more robust biofilms than the VSE E. faecium isolate (p < 0.001). The VRE E. faecium isolates, which generated larger biofilms than the VSE E. faecium isolate, could have remained protected in the heart valve and only caused bacteremia when disrupted during cardiac surgery. This study demonstrates that bacteria detected in the bloodstream of patients with endocarditis may not fully represent the organisms adherent to the cardiac valves or indwelling devices.

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

Vancomycin-resistant enterococcus (VRE) is a pathogen of growing concern due to increasing development of antibiotic resistance, increasing length of hospitalizations and excess mortality. The utility of some infection control practices are debatable, as newer developments in infection prevention strategies continued to be discovered. This article summarizes the significance of VRE and VRE transmission, along with highlighting key changes in infection control practices within the past 5 years.

Evidence Map and Systematic Review of Disinfection Efficacy on Environmental Surfaces in Healthcare Facilities

Healthcare-associated infections (HAIs) contribute to patient morbidity and mortality with an estimated 1.7 million infections and 99,000 deaths costing USD $28-34 billion annually in the United States alone. There is little understanding as to if current environmental surface disinfection practices reduce pathogen load, and subsequently HAIs, in critical care settings. This evidence map includes a systematic review on the efficacy of disinfecting environmental surfaces in healthcare facilities. We screened 17,064 abstracts, 635 full texts, and included 181 articles for data extraction and study quality assessment. We reviewed ten disinfectant types and compared disinfectants with respect to study design, outcome organism, and fourteen indictors of study quality. We found important areas for improvement and gaps in the research related to study design, implementation, and analysis. Implementation of disinfection, a determinant of disinfection outcomes, was not measured in most studies and few studies assessed fungi or viruses. Assessing and comparing disinfection efficacy was impeded by study heterogeneity; however, we catalogued the outcomes and results for each disinfection type. We concluded that guidelines for disinfectant use are primarily based on laboratory data rather than a systematic review of in situ disinfection efficacy. It is critically important for practitioners and researchers to consider system-level efficacy and not just the efficacy of the disinfectant.

Predictors of prolonged vancomycin-resistant enterococci colonization in acute stroke patients admitted to an intensive care unit: A retrospective cohort study

To investigate the factors affecting the duration of vancomycin-resistant enterococci (VRE) colonization in stroke patients.A total of 52 stroke patients with VRE colonization were enrolled. We divided the groups into several factors and confirmed whether each factor affected VRE colonization. Independent t test, bivariate correlation analysis, and Cox proportional hazards model were used to confirm statistical significance.Among 52 patients, 28 were ischemic stroke and 24 were hemorrhagic stroke. The mean duration of the VRE colonization was 39.08 ± 44.22 days. The mean duration of VRE colonization of the ischemic stroke patients was 25.57 ± 30.23 days and the hemorrhagic stroke patients was 54.83 ± 52.75 days. The mean intensive care unit (ICU) care period was 15.23 ± 21.98 days. Independent sample t test showed the hemorrhagic stroke (P < .05), use of antibiotics (P < .01), oral feeding (P < .01) were associated with duration of VRE colonization. Bivariate correlation analysis showed duration of ICU care (P < .001) was associated with duration of VRE colonization. Cox proportional hazard model showed oral feeding (P = .001), use of antibiotics (P = .003), and duration of ICU care (P = .001) as independent factors of duration of VRE colonization.Careful attention should be given to oral feeding, duration of ICU care, and use of antibiotics in stroke patients, especially hemorrhagic stroke patients, for intensive rehabilitation at the appropriate time.

Microbial Air Quality in Healthcare Facilities

There is increasing evidence that indoor air quality and contaminated surfaces provide an important potential source for transmission of pathogens in hospitals. Airborne hospital microorganisms are apparently harmless to healthy people. Nevertheless, healthcare settings are characterized by different environmental critical conditions and high infective risk, mainly due to the compromised immunologic conditions of the patients that make them more vulnerable to infections. Thus, spread, survival and persistence of microbial communities are important factors in hospital environments affecting health of inpatients as well as of medical and nursing staff. In this paper, airborne and aerosolized microorganisms and their presence in hospital environments are taken into consideration, and the factors that collectively contribute to defining the infection risk in these facilities are illustrated.

Using a multimodal strategy to improve patient hand hygiene

OBJECTIVE

The role of health care worker hand hygiene in preventing health care associated infections (HCAI) is well-established. There is less emphasis on the hand hygiene (HH) of hospitalized patients; in the context of COVID-19 mechanisms to support it are particularly important. The purpose of this study was to establish if providing patient hand wipes, and a defined protocol for encouraging their use, was effective in improving the frequency of patient HH (PHH).

DESIGN

Before and after study.

SETTIN

General Hospital, United Kingdom.

PARTICIPANTS

All adult patients admitted to 6 acute elderly care/rehabilitation hospital wards between July and October 2018.

METHODS

Baseline audit of PHH opportunities conducted over 6 weeks. Focus group with staff and survey of the public informed the development of a PHH bundle. Effect of bundle on PHH monitored by structured observation of HH opportunities over 12 weeks.

RESULTS

During baseline 303 opportunities for PHH were observed; compliance with PHH was 13.2% (40/303; 95% confidence interval 9.9-7.5). In the evaluation of PHH bundle, 526 PHH opportunities were observed with HH occurring in 58.9% (310/526); an increase of 45.7% versus baseline (95% confidence interval 39.7%-51.0%; P < .001).

CONCLUSION

Providing patients with multiwipe packs of handwipes is a simple, cost-effective approach to increasing PHH and reducing the risk of HCAI in hospital. Health care workers play an essential role in encouraging PHH.

Genomic and phenotypic diversity of Enterococcus faecalis isolated from endophthalmitis

Enterococcus faecalis are hospital-associated opportunistic pathogens and also causative agents of post-operative endophthalmitis. Patients with enterococcal endophthalmitis often have poor visual outcomes, despite appropriate antibiotic therapy. Here we investigated the genomic and phenotypic characteristics of E. faecalis isolates collected from 13 patients treated at the University of Pittsburgh Medical Center Eye Center over 19 years. Comparative genomic analysis indicated that patients were infected with E. faecalis belonging to diverse multi-locus sequence types (STs) and resembled E. faecalis sampled from clinical, commensal, and environmental sources. We identified known E. faecalis virulence factors and antibiotic resistance genes in each genome, including genes conferring resistance to aminoglycosides, erythromycin, and tetracyclines. We assessed all isolates for their cytolysin production, biofilm formation, and antibiotic susceptibility, and observed phenotypic differences between isolates. Fluoroquinolone and cephalosporin susceptibilities were particularly variable between isolates, as were biofilm formation and cytolysin production. In addition, we found evidence of E. faecalis adaptation during recurrent endophthalmitis by identifying genetic variants that arose in sequential isolates sampled over eight months from the same patient. We identified a mutation in the DNA mismatch repair gene mutS that was associated with an increased rate of spontaneous mutation in the final isolate from the patient. Overall this study documents the genomic and phenotypic variability among E. faecalis causing endophthalmitis, as well as possible adaptive mechanisms underlying bacterial persistence during recurrent ocular infection.

Bacterial survival on inanimate surfaces: a field study

OBJECTIVE

Environmental surfaces may serve as potential reservoirs for nosocomial pathogens and facilitate transmissions via contact depending on its tenacity. This study provides data on survival kinetics of the most important nosocomial bacteria on a panel of commonly used surfaces. Type strains of S. aureus, K. pneumoniae, P. aeruginosa, A. baumannii, S. marcescens, E. faecium, E. coli, and E. cloacae were suspended in 0.9% NaCl solution at a McFarland of 1 and got then plated via cotton swabs either on glass, polyvinyl chloride, stainless steel, or aluminum. Surfaces were stored at regular ambient temperature and humidity to simulate routine daycare conditions. Sampling was performed by contact plates for a time period of four weeks.

RESULTS

The longest survival was observed for A. baumannii and E. faecium on all materials (at least four weeks). S. aureus remained viable for at least one week. Gram negative species other than A. baumannii were usually inactivated in less than two days. Nosocomial transmission of the above mentioned bacteria may easily occur if no appropriate infection control measures are applied on a regular daily basis. This might be of particular importance when dealing with outbreaks of A. baumannii and E. faecium.

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.

Bacterial growth and recovery on hospital biometric devices: effect of two types of disinfectants

Objectives:

The aim of the study was to evaluate the presence of bacterial contamination on biometric identification devices in a public hospital; identify the species of bacteria implicated in the contamination and assess bacterial recovery after the use of 2 types of disinfectants: alcohol 70% and isopropyl alcohol chlorhexidine.

Design:

Before and after trial.

Setting:

Public hospital, tertiary referral center.

Participants:

All existing biometric identification devices in the hospital (n = 20).

Methods:

Collection of 2 microbiological samples from the fingerprint reading surface of biometric devices immediately before and after applying the solution with alcohol 70% and in separate time periods with isopropyl alcohol chlorhexidine.

Results:

It have been identified 21 different bacterial species in a total of 78 samples, mostly Staphylococcus epidermidis (32 samples) and S aureus (7 samples). S epidermidis was eliminated in 61.5% of the samples after disinfecting with alcohol 70% and in 92.3% of the samples disinfected with isopropyl alcohol chlorhexidine. S aureus was eliminated in 33.3% and 100% of the samples, respectively. We found no bacterial growth in 10% of the devices after disinfection with 70% alcohol and in 78.9% of devices after disinfection with isopropyl alcohol chlorhexidine. We also found that there was a decrease in the frequency of species isolated after using both disinfection solutions, although isopropyl alcohol chlorhexidine appeared to be more effective.

Conclusions:

The biometric identification devices used in this hospital seem to be safe regardless of the products used for its cleaning. The majority of the bacteria found are commensal skin microorganisms. We did not find pathogenic bacteria for immunocompetent individuals, in particular methicillin-resistant S aureus.

Persistence of Pathogens on Inanimate Surfaces: A Narrative Review

For the prevention of infectious diseases, knowledge about transmission routes is essential. In addition to respiratory, fecal-oral, and sexual transmission, the transfer of pathogens via surfaces plays a vital role for human pathogenic infections-especially nosocomial pathogens. Therefore, information about the survival of pathogens on surfaces can have direct implications on clinical measures, including hygiene guidelines and disinfection strategies. In this review, we reviewed the existing literature regarding viral, bacterial, and fungal persistence on inanimate surfaces. In particular, the current knowledge of the survival time and conditions of clinically relevant pathogens is summarized. While many pathogens persist only for hours, common nosocomial pathogens can survive for days to weeks under laboratory conditions and thereby potentially form a continuous source of transmission if no adequate inactivation procedures are performed.

Are your hands clean? Pollen retention on the human hand after washing

Pollen retention on clothes, footwear, hair and body has been used to link people to localities with distinctive vegetation, or soils containing distinctive palynomorphs. Little attention has been given to human skin as a possible medium for carrying a forensically important pollen load and whether this might survive attempts to remove it. We report here the results of experiments testing the retention of pollen of 10 flowering plant species on the human skin through repeated cycles of washing and drying hands, using the WHO protocol to standardize hand-washing and drying. Between 0.36% and 2.74% (mean 0.93%) of the initial pollen load was retained through a single hand-wash. Trace amounts of some species survived multiple hand-wash cycles. It is concluded that forensic analyses can be made of the pollen load of those parts of the skin that may have been in contact with palynologically distinctive vegetation, even in cases where the person involved has washed, or been washed. These observations may also be of relevance in cases where human skin became contaminated with other microscopic particulates.

Outbreak of vancomycin-resistant Enterococcus faecium clone ST796, Switzerland, December 2017 to April 2018

A large outbreak of vancomycin-resistant enterococci (VRE) is affecting four hospitals in the Canton of Bern, Switzerland, since December 2017. Of 89 cases identified as carriers, 77 (86.5%) VRE isolates were virtually indistinguishable using whole genome sequencing, and identified as multilocus sequence type (MLST) ST796. This clone, previously only described in Australia and New Zealand, is characterised by rapid spread and the ability to cause bloodstream infections. It requires a multifaceted infection prevention effort.

In search of novel protein drug targets for treatment of Enterococcus faecalis infections

Enterococcus faecalis (Ef) is one of the major pathogens involved in hospital-acquired infections. It can cause nosocomial bacteremia, surgical wound infection, and urinary tract infection. It is important to mention here that Ef is developing resistance against many commonly occurring antibiotics. The occurrence of multidrug resistance (MDR) and extensive-drug resistance (XDR) is now posing a major challenge to the medical community. In this regard, to combat the infections caused by Ef, we have to look for an alternative. Rational structure-based drug design exploits the three-dimensional structure of the target protein, which can be unraveled by various techniques such as X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. In this review, we have discussed the complete picture of Ef infections, the possible treatment available at present, and the alternative treatment options to be explored. This study will help in better understanding of novel biological targets against Ef and the compounds, which are likely to bind with these targets. Using these detailed structural informations, rational structure-based drug design is achievable and tight inhibitors against Ef can be prepared.

An epidemiological and molecular study regarding the spread of vancomycin-resistant Enterococcus faecium in a teaching hospital in Bogotá, Colombia 2016

Background

Enterococcus faecium is ranked worldwide as one of the top ten pathogens identified in healthcare-associated infections (HAI) and is classified as one of the high priority pathogens for research and development of new antibiotics worldwide. Due to molecular biology techniques’ higher costs, the approach for identifying and controlling infectious diseases in developing countries has been based on clinical and epidemiological perspectives. Nevertheless, after an abrupt vancomycin-resistant Enterococcus faecium dissemination in the Méderi teaching hospital, ending up in an outbreak, further measures needed to be taken into consideration. The present study describes the vancomycin-resistant Enterococcus faecium pattern within Colombian’s largest installed-bed capacity hospital in 2016.

Methods

Thirty-three vancomycin-resistant Enterococcus faecium isolates were recovered during a 5-month period in 2016. Multilocus variable-number tandem-repeat analysis was used for molecular typing to determine clonality amongst strains. A modified time-place-sequence algorithm was used to trace VREfm spread patterns during the outbreak period and estimate transmission routes.

Results

Four clonal profiles were identified. Chronological clonal profile follow-up suggested a transitional spread from profile “A” to profile “B”, returning to a higher prevalence of “A” by the end of the study. Antibiotic susceptibility indicated high-level vancomycin-resistance in most isolates frequently matching vanA gene identification.

Discussion

Transmission analysis suggested cross-contamination via healthcare workers. Despite epidemiological control of the outbreak, post-outbreak isolates were still being identified as having outbreak-related clonal profile (A), indicating reduction but not eradication of this clonality. This study supports the use of combined molecular and epidemiological strategies in an approach to controlling infectious diseases. It contributes towards a more accurate evaluation of the effectiveness of the epidemiological measures taken regarding outbreak control and estimates the main cause related to the spread of this microorganism.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3877-7) contains supplementary material, which is available to authorized users.

An outbreak of vanA vancomycin-resistant Enterococcus faecium in a hospital with endemic vanB VRE

BACKGROUND

In Australia, vanB vancomycin-resistant Enterococcus faecium (VREfm) has been endemic for over 20 years, but vanA VREfm isolates have rarely been reported.

METHODS

This outbreak report describes an outbreak of vanA VREfm in the intensive care unit (ICU) and cardiothoracic surgery (CTS) wards of a Melbourne hospital in 2015-2016. After the cluster was initially identified in the ICU ward, an active screening programme was implemented. VRE isolates were typed using in silico multi-locus sequence typing. In addition, to screening, enhanced environmental cleaning, chlorhexidine gluconate body washes, and standardisation of the surgical antibiotic prophylaxis regimen were implemented to control the outbreak.

RESULTS

There were 83 new isolates of vanA VREfm recovered from patients in the ICU (n = 31) and CTS (n = 52) wards. Screening identified 78 (94%) of cases. Three patients required treatment for clinical infection with vanA VREfm during the outbreak. The outbreak was polyclonal with 5 different multilocus sequence types carrying the vanA gene (ST17, ST80, ST203, ST252 and ST1421) detected from a subset of isolates (N = 43). The ST17 isolates all carried both the vanA and vanB gene. The intervention bundle resulted in control of the outbreak after 10 months.

CONCLUSION

Geographically, vanA VREfm has previously been uncommon in the region and this outbreak represents a change in local epidemiology. Few VRE outbreaks have been reported in CTS patients. The infection control responses controlled the outbreak within 10-months and may help guide future management of outbreaks.

Bacterial burden is associated with increased transmission to health care workers from patients colonized with vancomycin-resistant Enterococcus

BACKGROUND

Health care workers (HCWs) are significant vectors for transmission of multidrug-resistant organisms among patients in intensive care units (ICUs). We studied ICU patients on contact precautions, colonized with vancomycin-resistant Enterococcus (VRE), to assess whether bacterial burden is associated with transmission to HCWs' gloves or gowns, a surrogate outcome for transmission to subsequent patients.

METHODS

From this prospective cohort study, we analyzed 96 VRE-colonized ICU patients and 5 HCWs per patient. We obtained samples from patients' perianal area, skin, and stool to assess bacterial burden and cultured HCWs' gloves and gowns for VRE after patient care.

RESULTS

Seventy-one of 479 (15%) HCW-patient interactions led to contamination of HCWs' gloves or gowns with VRE. HCW contamination was associated with VRE burden on the perianal swab (odds ratio [OR], 1.37; 95% confidence interval [CI], 1.19, 1.57), skin swabs (OR, 2.14; 95% CI, 1.51, 3.02), and in stool (OR, 1.95; 95% CI, 1.39, 2.72). Compared with colonization with Enterococcus faecalis, colonization with Enterococcus faecium was associated with higher bacterial burden and higher odds of transmission to HCWs.

CONCLUSIONS

We show that ICU patients with higher bacterial burden are more likely to transmit VRE to HCWs. These findings have implications for VRE decolonization and other infection control interventions.

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

BACKGROUND

A large outbreak of three epidemic vancomycin-resistant Enterococcus faecium (VRE) clones affected the study hospital for almost two years.

AIM

To describe the strategy to successfully control this outbreak and eradicate VRE from the study hospital.

METHODS

Infection control interventions started after detection of VRE in three patients. Hospital-wide surveillance was started after ongoing transmission despite isolation precautions, cleaning and contact tracing. Hygiene education and discipline were enhanced. Despite these interventions, additional measures were required to control the outbreak, such as ward disinfection with hydrogen peroxide vapour and the introduction of a VRE quarantine ward. Ultimately, ciprofloxacin prophylaxis for haematological patients on chemotherapy was abandoned.

FINDINGS

Over a 22-month period, 242 VRE carriers were identified. Of these, 128 (53%) patients were detected by hospital-wide surveillance alone. Three epidemic clones were detected: ST494-vanA (N = 160), ST78-vanA (N = 23) and ST117-vanB (N = 32). In total, 5614 possible contacts were identified. VRE transmission occurred on 13 out of 23 wards. VRE was cultured from clinical specimens in 22 patients (seven with bacteraemia). Since January 2014, no further transmission of these VRE clones has been observed.

CONCLUSION

Infection control measures according to international guidelines were insufficient to expose the outbreak to its full extent and control it. Its full extent only became apparent after sustained hospital-wide screening. Successful control of this hospital-wide VRE outbreak was feasible, but required great effort. Final containment and eradication of the epidemic clones was achieved by environmental decontamination with hydrogen peroxide vapour, strict isolation precautions, a VRE quarantine ward and antimicrobial stewardship.

Long-term metabolic persistence of gram-positive bacteria on health care-relevant plastic

BACKGROUND

Health care-associated opportunistic pathogens Staphylococcus aureus and Enterococcus faecium persist on dry environments and can contribute to organism transmission through contact. These organisms can be monitored on surfaces by culture, molecular methods, or metabolic assays. This study was designed to determine the kinetics of bacterial persistence on acrylonitrile butadiene styrene, a plastic commonly used in the manufacture of bedrails.

MATERIALS AND METHODS

Polymerase chain reaction for genomic DNA was used to confirm the presence of bacteria cells on this plastic irrespective of viability. Bacterial viability was measured by culture, ATP quantification, and a metabolic assay at time points up to and longer than 1 year.

RESULTS

Polymerase chain reaction confirmed the presence of bacteria on the plastic for the entire time period studied. However, S aureus culturability was reduced after 3 and 7 weeks; neither organism was culturable after 1 year. At 7 weeks, ATP levels were reduced for both organisms, paralleling S aureus culturability but indicating that ATP quantification did not predict E faecium culturability. S aureus-reducing potential was reduced after 7 weeks, whereas E faecium-reducing potential reached the level of fresh inoculum after 12 hours in broth culture. Low but significant levels of metabolic activity were detected for each organism after 1 year.

CONCLUSIONS

S aureus and E faecium cells may retain viability on plastic for longer than 1 year.

Effect of automated ultraviolet C-emitting device on decontamination of hospital rooms with and without real-time observation of terminal room disinfection

BACKGROUND

We studied the effectiveness of an ultraviolet C (UV-C) emitter in clinical settings and compared it with observed terminal disinfection.

METHODS

We cultured 22 hospital discharge rooms at a tertiary care academic medical center. Phase 1 (unobserved terminal disinfection) included cultures of 11 high-touch environmental surfaces (HTSs) after terminal room disinfection (AD) and after the use of a UV-C-emitting device (AUV). Phase 2 (observed terminal disinfection) included cultures before terminal room disinfection (BD), AD, and AUV. Zero-inflated Poisson regression compared mean colony forming units (CFU) between the groups. Two-sample proportion tests identified significance of the observed differences in proportions of thoroughly cleaned HTSs (CFU < 5). Significant P value was determined using the Bonferroni corrected threshold of α = .05/12 = .004.

RESULTS

We obtained 594 samples. Risk of overall contamination was 0.48 times lower in the AUV group than in the AD group (P < .001), with 1.04 log₁₀ reduction. During phase 1, overall proportion of HTSs with <5 CFUs increased in AUV versus AD by 0.12 (P = .001). During phase 2, it increased in AD versus BD by 0.45 (P < .001), with no significant difference between AD and AUV (P = .02).

CONCLUSIONS

Use of UV-C with standard cleaning significantly reduced microbial burden and improved the thoroughness of terminal disinfection. We found no further benefit to UV-C use if standard terminal disinfection was observed.

Bacterial bloodstream infections in the allogeneic hematopoietic cell transplant patient: new considerations for a persistent nemesis

Bacterial bloodstream infections (BSI) cause significant transplant-related morbidity and mortality following allogeneic hematopoietic cell transplantation (allo-HCT). This manuscript reviews the risk factors for and the bacterial pathogens causing BSIs in allo-HCT recipients in the contemporary transplant period. In addition, it offers insight into emerging resistant pathogens and reviews clinical management considerations to treat and strategies to prevent BSIs in allo-HCT patients.

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

Vancomycin-resistant enterococci (VRE) infections have acquired prominence as a leading cause of health care-associated infections. Understanding VRE epidemiology, transmission modes in health care settings, risk factors for colonization, and infection is essential to prevention and control of VRE infections. Infection control strategies are pivotal in management of VRE infections and should be based on patient characteristics, hospital needs, and available resources. Hand hygiene is basic to decrease acquisition of VRE. The effectiveness of surveillance and contact precautions is variable and controversial in endemic settings, but important during VRE outbreak investigations and control. Environmental cleaning, chlorhexidine bathing, and antimicrobial stewardship are vital in VRE prevention and control.

Persistent environmental reservoirs for Vancomycin-resistant enterococci requiring repeated decontamination to achieve eradication

V ancomycin-resistant enterococci (VRE) are increasingly recognised nosocomial pathogens in clinical areas with high antibiotic usage. Patients with chronic renal failure, including those requiring haemodialysis, are at particular risk. Investigation and control of an outbreak of VRE in two renal wards, highlighting mattresses as reservoirs and environmental measures to control VRE are reported in this paper. Outbreak control measures included standard isolation in accordance with the Recommendations of the Hospital Infection Control Practices Advisory Committee (HICPAC). Patients were screened on admission and weekly using a rectal swab. The inanimate environment including mattresses was also screened. Enhanced environmental decontamination was performed on a daily basis.

The outbreak continued over a 20-week period with most cases occurring in the first 6 weeks. The results of screening indicated that 59 (13%) of 451 patients and 54 (8.3%) of 647 environmental samples were positive for VRE. VRE was isolated from 35 (8%) of 433 mattresses, 12 (8.1%) of 148 environmental ledges, 4 (8%) of 50 toilets, and 3 (18.8%) of 16 items of cleaning equipment. Molecular typing indicated that a predominant strain was also implicated in mattress contamination, thus highlighting a potential and important reservoir for transmission of VRE. Difficulty with eradication of VRE from the environment was encountered despite enhanced cleaning regimens and a doubling of use of disinfectant was necessary.

Restriction of antibiotics, hand hygiene, hygiene and education are the cornerstone of VRE prevention and control. Lessons from this outbreak highlight the role of the environment in VRE transmission and the need for attention to the environment, especially mattress decontamination.

Control of Vancomycin-Resistant Enterococci in the Neonatal Intensive Care Unit

Background and Objective:

Multidrug-resistant organisms (MDROs), such as vancomycin-resistant enterococci (VRE), cause serious infections, especially among high-risk patients in NICUs. When VRE was introduced and transmitted in our NICU despite recommended infection control practices, we instituted active surveillance cultures to determine their efficacy in detecting and controlling spread of VRE among high-risk infants.

Methods:

Active surveillance cultures, other infection control measures, and a mandatory in-service education module on preventing MDRO transmission were implemented. Cultures were performed on NICU admission and then weekly during their stay. Molecular DNA fingerprinting of VRE isolates facilitated targeting efforts to eliminate clonal spread of VRE. Repetitive sequence PCR (rep-PCR)-based DNA fingerprinting was used to compare isolates recovered from patients with VRE infection or colonization. Environmental VRE cultures were performed around VRE-colonized or -infected patients. DNA fingerprints were prepared from the products of rep-PCR amplification and analyzed using software to determine strain genetic relatedness.

Results:

Active surveillance cultures identified 65 patients with VRE colonization or infection among 1,820 admitted to the NICU. Rep-PCR performed on 60 VRE isolates identified 3 clusters. Cluster 1 included isolates from 21 patients and 4 isolates from the environment of the index patient. Clusters 2 and 3 included isolates from 23 and 3 patients, respectively. Similarity coefficients among the members of each cluster were 95% or greater.

Conclusions:

Control of transmission of multi-clonal VRE strains was achieved. Active surveillance cultures, together with implementation of other infection control measures, combined with rep-PCR DNA fingerprinting were instrumental in controlling VRE transmission in our NICU. (Infect Control Hosp Epidemiol 2005;26:646-649)

Analysis and recommendations for reducing risks of patient crosscontaminations via noncritical medical devices

Based on the serious problem of health care-associated infections and the understanding that patient crosscontamination is essentially preventable, opinions were sought from health care providers for insight into likely sources of crosscontamination in US hospitals, probable causes, and areas for additional investigation. Respondents indicated that inadequate disinfection of noncritical, patient care devices pose an underrecognized threat to patient crosscontamination. This led the researchers to question reliance upon the current Centers for Disease Control and Prevention (CDC) Guideline for Disinfection and Sterilization in Healthcare Facilities for such items. The CDC Guideline follows the Spaulding approach, which categorizes items and their disinfection treatment based on the risk of infection from the intended use of the item. A failure modes, effects, and criticality analysis approach is recommended as an additional refinement to the CDC Guideline whereby likely sources of cross-contamination are identified irrespective of intended use. Enhancing infection control practices with this approach promotes the development of preventive plans for cleaning and disinfection that can mitigate such risk.

Vancomycin-resistant enterococci: Troublemaker of the 21st century

The emergence of multidrug-resistant and vancomycin-resistant enterococci during the last decade has made it difficult to treat nosocomial infections. Although various enterococcal species have been identified, only two (Enterococcus faecalis and Enterococcus faecium) are responsible for the majority of human infections. Vancomycin is an important therapeutic alternative against multidrug-resistant enterococci but is associated with a poor prognosis. Resistance to vancomycin dramatically reduces the therapeutic options for enterococcal infections. The bacterium develops resistance by modifying the C-terminal d-alanine of peptidoglycan to d-lactate, creating a d-Ala-d-Lac sequence that effectively reduces the affinity of vancomycin for the peptidoglycan by 1000-fold. Moreover, the resistance genes can be transferred from enterococci to Staphylococcus aureus, thereby posing a threat to patient safety and also a challenge for treating physicians. Judicious use of vancomycin and broad-spectrum antibiotics must be implemented, but strict infection control measures must also be followed to prevent nosocomial transmission of these organisms. Furthermore, improvements in clinical practice, rotation of antibiotics, herbal drugs, nanoantibiotics and the development of newer antibiotics based on a pharmacogenomic approach may prove helpful to overcome dreadful vancomycin-resistant enterococcal infections.

Individual variability in finger-to-finger transmission efficiency of Enterococcus faecium clones

A fingertip-to-fingertip intraindividual transmission experiment was carried out in 30 healthy volunteers, using four MLST-typed Enterococcus faecium clones. Overall results showed an adequate fit goodness to a theoretical exponential model, whereas four volunteers (13%) exhibited a significantly higher finger-to-finger bacterial transmission efficiency. This observation might have deep consequences in nosocomial epidemiology.

[Fungal and bacterial contamination of 30 general practitioners' consultation room in Franche-Comté (eastern France)]

OBJECTIVE

To evaluate the level of microbial contamination of general pratice environment.

METHODS

Ten points, including air, water and surfaces were sampled in general practitioner's consultation room of 30 general practices in Franche-Comté region (eastern France). For each sample, a global microbial count was assessed as well as the presence of potential pathogen microorganisms: Aspergillus fumigatus, Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacteriaceae.

RESULTS

We note that 66.3% of the samples (n=202) were on the target level (<51 ufc/25 cm (2), <101 ufc/m(3), <100 ufc/mL in total bacteria, without pathogenic species and without A. fumigatus respectively on surfaces, air and water, without isolation of coliforme bacteria or P. aeruginosa for 100mL of water). A. fumigatus, S. aureus, P. aeruginosa and Enterobacteriaceae were recovered in 8.0%, 2.1%, 0.7%, 0% respectively. However, 66.7% of air sampling were positive to A. fumigatus with 2 to 12 cfu/m(3).

CONCLUSION

This study shows a low level of bacterial contamination of general practitioner's consultation room. A. fumigatus frequency in air samples seems equivalent to that found in housing without air treatment.

Surveillance of bacterial contamination in small animal veterinary hospitals with special focus on antimicrobial resistance and virulence traits of enterococci

OBJECTIVE

To determine the prevalence of bacterial contamination on 4 surfaces of 4 types of standard equipment in small animal veterinary hospitals.

DESIGN

Surveillance study.

SAMPLE

10 small animal veterinary hospitals.

PROCEDURES

Each hospital was visited 3 times at 4-month intervals; at each visit, a cage door, stethoscope, rectal thermometer, and mouth gag were swabbed. Swab samples were each plated onto media for culture of enterococci and organisms in the family Enterobacteriaceae. Enterococci were identified via a species-specific PCR assay and sodA gene sequencing; species of Enterobacteriaceae were identified with a biochemical test kit. Antimicrobial susceptibility was assessed via the disk diffusion method. Enterococci were screened for virulence traits and genotyped to assess clonality.

RESULTS

Among the 10 hospitals, enterococci were isolated from cage doors in 7, from stethoscopes in 7, from thermometers in 6, and from mouth gags in 1; contamination with species of Enterobacteriaceae was rare. Enterococci were mainly represented by Enterococcus faecium (35.4%), Enterococcus faecalis (33.2%), and Enterococcus hirae (28.3%). Antimicrobial resistance was common in E. faecium, whereas virulence traits were present in 99% of E. faecalis isolates but not in E. faecium isolates. Clonal multidrug-resistant E. faecium was isolated from several surfaces at 1 hospital over multiple visits, whereas sporadic nonclonal contamination was detected in other hospitals.

CONCLUSIONS AND CLINICAL RELEVANCE

Contamination of surfaces in small animal veterinary hospitals with multidrug-resistant enterococci is a potential concern for pets and humans contacting these surfaces. Implementing precautions to minimize enterococcal contamination on these surfaces is recommended.

Control and mitigation of healthcare-acquired infections: designing clinical trials to evaluate new materials and technologies

Hospitals clean environmental surfaces to lower microbial contamination and reduce the likelihood of transmitting infections. Despite current cleaning and hand hygiene protocols, hospital-acquired infections (HAIs) continue to result in a significant loss of life and cost the U.S. healthcare system an estimated $45 billion annually. Stainless steel and chrome are often selected for hospital touch surfaces for their "clean appearance," comparatively smooth finish, resistance to standard cleaners, and relative effectiveness for removing visible dirt during normal cleaning. Designers use wood surfaces for aesthetics; plastic surfaces have become increasingly endemic for their relative lower initial cost; and "antimicrobial agents" are being incorporated into a variety of surface finishes.This paper concentrates on environmental surface materials with a history of bactericidal control of infectious agents and focuses on the methods necessary to validate their effectiveness in healthcare situations. Research shows copper-based metals to have innate abilities to kill bacteria in laboratory settings, but their effectiveness in patient care environments has not been adequately investigated. This article presents a research methodology to expand the evidence base from the laboratory to the built environment. For such research to have a meaningful impact on the design/specifying community, it should assess typical levels of environmental pathogens (i.e., surface "cleanliness") as measured by microbial burden (MB); evaluate the extent to which an intervention with copper-based materials in a randomized clinical trial affects the level of contamination; and correlate how the levels of MB affect the incidence of infections acquired during hospital stays.

Microbial biogeography of public restroom surfaces

We spend the majority of our lives indoors where we are constantly exposed to bacteria residing on surfaces. However, the diversity of these surface-associated communities is largely unknown. We explored the biogeographical patterns exhibited by bacteria across ten surfaces within each of twelve public restrooms. Using high-throughput barcoded pyrosequencing of the 16 S rRNA gene, we identified 19 bacterial phyla across all surfaces. Most sequences belonged to four phyla: Actinobacteria, Bacteriodetes, Firmicutes and Proteobacteria. The communities clustered into three general categories: those found on surfaces associated with toilets, those on the restroom floor, and those found on surfaces routinely touched with hands. On toilet surfaces, gut-associated taxa were more prevalent, suggesting fecal contamination of these surfaces. Floor surfaces were the most diverse of all communities and contained several taxa commonly found in soils. Skin-associated bacteria, especially the Propionibacteriaceae, dominated surfaces routinely touched with our hands. Certain taxa were more common in female than in male restrooms as vagina-associated Lactobacillaceae were widely distributed in female restrooms, likely from urine contamination. Use of the SourceTracker algorithm confirmed many of our taxonomic observations as human skin was the primary source of bacteria on restroom surfaces. Overall, these results demonstrate that restroom surfaces host relatively diverse microbial communities dominated by human-associated bacteria with clear linkages between communities on or in different body sites and those communities found on restroom surfaces. More generally, this work is relevant to the public health field as we show that human-associated microbes are commonly found on restroom surfaces suggesting that bacterial pathogens could readily be transmitted between individuals by the touching of surfaces. Furthermore, we demonstrate that we can use high-throughput analyses of bacterial communities to determine sources of bacteria on indoor surfaces, an approach which could be used to track pathogen transmission and test the efficacy of hygiene practices.

Risk factors for vancomycin-resistant enteroccocci colonization in infants in neonatal intensive care unit

We aimed to evaluate the risk factors for VRE colonization in neonatal intensive care units. In December 2007, we identified a neonate with VRE infection (urinary tract infection and we performed blood and stool cultures for VRE until the last colonized patient was discharged from our clinic. All the neonates hospitalized in NICU during December 2007 to January 2008. Active surveillance cultures for VRE fecal carriage was carried out in neonatal intensive care unit. Resistance to vancomycin was detected by the E-test method. Epidemiological data was recorded for all patients included in the study and was used for the risk factors. Totally 54 infants in NICU were screened for VRE colonization. Totally 11 infants (20%) were colonized with vancomycin-resistant enterococci. The average duration of all antimicrobial therapy was significantly longer in colonized patients. The infants who were hospitalized for more than 10 days were found to be significantly more colonized with VRE when compared to the infants with shorter hospital stay (p<0.05). There were no statistically significant differences between VRE colonized and non-colonized infants in respect to sex, to third generation cephalosporin usage, glycopeptide usage, presence of prematurity, presence of mechanical ventilation(p> 0.05). The premature infants and the mature infants were under risk of VRE colonization. Longer duration of hospitalization and antimicrobial usage were the prominent risk factors. Since infants in neonatal intensive care units were under risk of infections, periodic active surveillance cultures should be combined with logical antimicrobial therapy.