A comparison of persistence of SARS-CoV-2 variants on stainless steel.

The survival of newer variants of SARS-CoV-2 on a representative surface has been compared to the established UK circulating isolate to determine whether enhanced environmental stability could play a part in their increased transmissibility. Stainless steel coupons were inoculated with liquid cultures of the three variants, with coupons recovered over seven days and processed for recoverable viable virus using plaque assay. After drying, there was no significant difference in inactivation rates between variants, indicating that there is no increased environmental persistence from the new variants.

The transfer of unsterilized material from Mars to Phobos: Laboratory tests, modelling and statistical evaluation.

Sample return missions to Phobos are the subject of future exploration plans. Given the proximity of Phobos to Mars, Mars' potential to have supported life, and the possibility of material transfer from Mars to Phobos, careful consideration of planetary protection is required. If life exists, or ever existed, on Mars, there is a possibility that material carrying organisms could be present on Phobos and be collected by a sample return mission such as the Japanese Martian Moons eXplorer (MMX). Here we describe laboratory experiments, theoretical modelling and statistical analysis undertaken to quantify whether the likelihood of a sample from Phobos material containing unsterilized material transferred from Mars is less than 10-6, the threshold to transition between restricted and unrestricted sample return classification for planetary protection. We have created heat, impact and radiation sterilization models based on the Phobos environment, and through statistical analyses investigated the level of sterilization expected for martian material transferred to Phobos. These analyses indicate that radiation is the major sterilization factor, sterilizing the Phobos surface over timescales of millions of years. The specific events of most relevance in the Phobos sample return context are the 'young' cratering events on Mars that result in Zunil-sized craters, which can emplace a large mass of martian material on Phobos, in a short period of time, thus inhibiting the effects of radiation sterilization. Major unknowns that cannot yet be constrained accurately enough are found to drive the results - the most critical being the determination of exact crater ages to statistical certainty, and the initial biological loading on Mars prior to transfer. We find that, when taking a conservative perspective and assuming the best-case scenario for organism survival, for a 100 g sample of the Phobos regolith to be below the planetary protection requirement for unrestricted sample return, the initial biological loading on Mars must be <8.2 × 103cfu kg-1. For the planned MMX mission, a ∼10 g sample to be obtained from a 25-30 mm diameter core as planned would require an initial martian biological loading to be <1.6 × 104cfu kg-1, in order to remain compliant with the planetary protection threshold.

Carbapenem-resistant Enterobacteriaceae dispersal from sinks is linked to drain position and drainage rates in a laboratory model system.

BACKGROUND: Hospital sinks, waste traps and drains can harbour carbapenem-resistant Enterobacteriaceae (CRE). AIM: To investigate the dispersal of CRE from sinks in which water delivered from the tap flows directly into the drain and from clinical handwash basins with the drain at the rear. The effect of fast and slow drainage rates was also assessed. METHODS: Waste traps, known to be colonized with CRE, were taken from a hospital and installed within a model laboratory system. New waste traps were also installed and artificially inoculated with CRE. The potential for bacteria to be dispersed from sinks was assessed using cyclone air samplers and/or settle plates. FINDINGS: When the waste traps were artificially contaminated and CRE colonization was confined to the waste trap water, significantly fewer bacteria were dispersed from sinks that drained quickly (P = 0.004) and/or from rear-draining sinks (P = 0.002). When the waste traps were naturally contaminated and CRE colonized the trap, pipework and drain, there was significant interaction between sink drainage and position of the drain (P < 0.001). When drainage was slow, dispersal from rear-draining sinks was almost 30-fold less than from sinks with the drain underneath the tap (P < 0.001). When drainage was fast, rear-draining sinks again released comparatively fewer CRE, although, in this case, the difference was not statistically significant (P = 0.7). Contaminated splashes travelled up to 1 m from the sink. CONCLUSION: Slow drainage rates and sink designs with the drain directly underneath the tap increase the risk of CRE present in waste traps and drains contaminating the ward environment.

Sampling and inactivation of wet disseminated spores from flooring materials, using commercially available robotic vacuum cleaners.

AIMS: Four commercially available robotic vacuum cleaners were assessed for sampling efficiency of wet disseminated Bacillus atrophaeus spores on carpet, polyvinyl chloride (PVC) and laminate flooring. Furthermore, their operability was evaluated and decontamination efficiency of one robot was assessed, using a sodium hypochlorite solution. METHODS AND RESULTS: In an environmental chamber, robots self-navigated around 4 m2 of flooring containing a single contaminated 0·25 m2 tile (c. 104 spores per cm2 ). Contamination levels at predetermined locations were assessed by macrofoam swabs (PVC and laminate) or water soluble tape (carpet), before and after sampling. Robots were dismantled postsampling and spore recoveries assessed. Aerosol contamination was also measured during sampling. Robot sampling efficiencies were variable, however, robots recovered most spores from laminate (up to 17·1%), then PVC and lastly the carpet. All robots spread contamination from the 'hotspot' (all robots spread <0·6% of the contamination to other areas) and became surface contaminated. Spores were detected at low levels during air sampling (<5·6 spores per litre). Liquid decontamination inactivated 99·1% of spores from PVC. CONCLUSIONS: Robotic vacuum cleaners show promise for both sampling and initial decontamination of indoor flooring. SIGNIFICANCE AND IMPACT OF THE STUDY: In the event of a bioterror incident, e.g. deliberate release of Bacillus anthracis spores, areas require sampling to determine the magnitude and extent of contamination, and to establish decontamination efficacy. In this study, we investigate robotic sampling methods against high concentrations of bacterial spores applied by wet deposition to different floorings, contamination spread to other areas, potential transfer of spores to the operators and assessment of a wet vacuum robot for spore inactivation. The robots' usability was evaluated and how they can be employed in real life scenarios. This will help to reduce the economic cost of sampling and the risk to sampling/decontamination teams.

Development of a sporicidal test method for Clostridium difficile.

BACKGROUND: Disinfectants with claimed activity against Clostridium difficile must be evaluated to ensure efficacy against the spores that comprise an environmental source of patient infection. Unfortunately there is, at present, no generally accepted method for evaluating these disinfectants. In the absence of such a method, laboratories have to adapt protocols that were not designed for products used in medical environments and consequently may use inappropriate test organisms, exposure times, and pass criteria. AIM: To develop and evaluate a method for testing the activity of disinfectants against C. difficile spores using exposure times and pass criteria which are relevant to clinical application. METHODS: A Joint Working Party of the Healthcare Infection Society (HIS) and the Advisory Committee on Antimicrobial Resistance and Healthcare Associated Infections (ARHAI) of the Department of Health in England was assembled. The Working Party adapted a previously described enzyme-based method for spore purification (the Clospore method) using an exposure time of 5 min and a 5 log10 kill as a pass criterion. FINDINGS: Evaluation of the method by three laboratories demonstrated that the method is simple to follow and that the results are repeatable and reproducible. CONCLUSION: The method described by the Working Party produces a clean suspension with a high titre of spores. It is recommended that, for a disinfectant used in the environment, the product should demonstrate a 5 log10 reduction in 5 min under clean or dirty conditions to fulfil the requirements of the test.

Cardiac magnetic resonance, transthoracic and transoesophageal echocardiography: a comparison of in vivo assessment of ventricular function in rats.

In vivo assessment of ventricular function in rodents has largely been restricted to transthoracic echocardiography (TTE). However 1.5 T cardiac magnetic resonance (CMR) and transoesophageal echocardiography (TOE) have emerged as possible alternatives. Yet, to date, no study has systematically assessed these three imaging modalities in determining ejection fraction (EF) in rats. Twenty rats underwent imaging four weeks after surgically-induced myocardial infarction. CMR was performed on a 1.5 T scanner, TTE was conducted using a 9.2 MHz transducer and TOE was performed with a 10 MHz intracardiac echo catheter. Correlation between the three techniques for EF determination and analysis reproducibility was assessed. Moderate-strong correlation was observed between the three modalities; the greatest between CMR and TOE (intraclass correlation coefficient (ICC) = 0.89), followed by TOE and TTE (ICC = 0.70) and CMR and TTE (ICC = 0.63). Intra- and inter-observer variations were excellent with CMR (ICC = 0.99 and 0.98 respectively), very good with TTE (0.90 and 0.89) and TOE (0.87 and 0.84). Each modality is a viable option for evaluating ventricular function in rats, however the high image quality and excellent reproducibility of CMR offers distinct advantages even at 1.5 T with conventional coils and software.

A comparison of sexual and reproductive health services provided by genitourinary and family planning clinics for adolescents.

The purpose of the study was to assess the use of sexual and reproductive health services by adolescents aged 15 years and younger. A case-note review was conducted at both a genitourinary medicine clinic and a family planning clinic in Edinburgh, UK. The demographics of the attendees, reasons for attending, risk factors, diagnostic tests undertaken and contraceptive advice given differed between the two clinics. Approximately 73% of attendees with documented responses used alcohol and 21% used recreational drugs, 5% reported self-harm, 25% reported being victims of sexual assault, 13% had a current sexually transmitted infection and 6% of girls had already been pregnant. While this group of young people understand the differences in emphasis between the clinics, adolescents may be intimidated and discouraged from attending or may fail to return, and the combination of overlap, together with omissions in cross-clinic function, suggests that for this age group the services of these clinics should be combined.

Enrichment for STRO-1 expression enhances the cardiovascular paracrine activity of human bone marrow-derived mesenchymal cell populations.

The cardiovascular therapeutic potential of bone marrow mesenchymal stromal/stem cells (MSC) is largely mediated by paracrine effects. Traditional preparation of MSC has involved plastic adherence-isolation. In contrast, prospective immunoselection aims to improve cell isolation by enriching for mesenchymal precursor cells (MPC) at higher purity. This study compared the biological characteristics and cardiovascular trophic activity of plastic adherence-isolated MSC (PA-MSC) and MPC prepared from the same human donors by immunoselection for stromal precursor antigen-1 (STRO-1). Compared to PA-MSC, STRO-1-MPC displayed greater (1) clonogenicity, (2) proliferative capacity, (3) multilineage differentiation potential, and (4) mRNA expression of mesenchymal stem cell-related transcripts. In vitro assays demonstrated that conditioned medium from STRO-1-MPC had greater paracrine activity than PA-MSC, with respect to cardiac cell proliferation and migration and endothelial cell migration and tube formation. In keeping with this, STRO-1-MPC exhibited higher gene and protein expression of CXCL12 and HGF. Inhibition of these cytokines attenuated endothelial tube formation and cardiac cell proliferation, respectively. Paracrine responses were enhanced by using supernatant from STRO-1(Bright) MPC and diminished with STRO-1(Dim) conditioned medium. Together, these findings indicate that prospective isolation gives rise to mesenchymal progeny that maintain a higher proportion of immature precursor cells compared to traditional plastic adherence-isolation. Enrichment for STRO-1 is also accompanied by increased expression of cardiovascular-relevant cytokines and enhanced trophic activity. Immunoselection thus provides a strategy for improving the cardiovascular reparative potential of mesenchymal cells.

Multipotential human adipose-derived stromal stem cells exhibit a perivascular phenotype in vitro and in vivo.

Mesenchymal stem-like cells identified in different tissues reside in a perivascular niche. In the present study, we investigated the putative niche of adipose-derived stromal/stem cells (ASCs) using markers, associated with mesenchymal and perivascular cells, including STRO-1, CD146, and 3G5. Immunofluorescence staining of human adipose tissue sections, revealed that STRO-1 and 3G5 co-localized with CD146 to the perivascular regions of blood vessels. FACS was used to determine the capacity of the CD146, 3G5, and STRO-1 specific monoclonal antibodies to isolate clonogenic ASCs from disassociated human adipose tissue. Clonogenic fibroblastic colonies (CFU-F) were found to be enriched in those cell fractions selected with either STRO-1, CD146, or 3G5. Flow cytometric analysis revealed that cultured ASCs exhibited similar phenotypic profiles in relation to their expression of cell surface markers associated with stromal cells (CD44, CD90, CD105, CD106, CD146, CD166, STRO-1, alkaline phosphatase), endothelial cells (CD31, CD105, CD106, CD146, CD166), haematopoietic cells (CD14, CD31, CD45), and perivascular cells (3G5, STRO-1, CD146). The immunoselected ASCs populations maintained their characteristic multipotential properties as shown by their capacity to form Alizarin Red positive mineralized deposits, Oil Red O positive lipid droplets, and Alcian Blue positive proteoglycan-rich matrix in vitro. Furthermore, ASCs cultures established from either STRO-1, 3G5, or CD146 selected cell populations, were all capable of forming ectopic bone when transplanted subcutaneously into NOD/SCID mice. The findings presented here, describe a multipotential stem cell population within adult human adipose tissue, which appear to be intimately associated with perivascular cells surrounding the blood vessels.

Incidence and risk factors for newly acquired hepatitis C virus infection among Aboriginal versus non-Aboriginal Canadians in six regions, 1999-2004.

The purpose of this study was to compare hepatitis C virus (HCV) incidence and recent patterns of transmission within Aboriginal and non-Aboriginal Canadians. Cases of newly acquired HCV infection (in patients > or =15 years) reported to the Enhanced Hepatitis Strain Surveillance System from six jurisdictions in Canada were analyzed. Information on demographic and clinical characteristics as well as risk factors for HCV infection was collected using standardized questionnaires. Univariate analysis showed Aboriginal patients to be significantly more likely than non-Aboriginal patients to report injection drug use (77.1% vs. 64.0%; p < 0.05), to be female (54.6% vs. 37.6%; p < 0.05), to report high-risk sexual behaviors (48.6% vs. 34.1%, p < 0.05), and to report drug snorting (45.7% vs. 32.7%, p < 0.05). The median age of Aboriginal patients was significantly younger than that of non-Aboriginal patients (31 years [range, 15-71] vs. 34 years [range, 15-81]; p < 0.05). The overall incidence of HCV infection per 100,000 people aged 15 years and older was 18.9 (95% confidence interval [CI] 15.5-23.1) in Aboriginal people and 2.8 (95%CI 2.6-3.1) in non-Aboriginal people. Poisson regression analysis revealed that Aboriginal Canadians were more likely than non-Aboriginal Canadians to develop acute hepatitis C (adjusted rate ratio 5.8, 95%CI 4.7-7.3). An appropriate and effective public health strategy that includes planned and implemented prevention programs in partnership with the Aboriginal community is needed.

Effects of combined exposure to pyridostigmine bromide and shaker stress on acoustic startle response, pre-pulse inhibition and open field behavior in mice.

The present study investigated the effect of combined exposure of pyridostigmine bromide (PB) and chronic shaker stress on acoustic startle responses (ASR), pre-pulse inhibition (PPI) and open field behavior of adult C57BL/6J mice. PB (10 mg kg(-1) day(-1) for 7 days) or saline was administered subcutaneously using osmotic Alzet minipumps implanted under the skin on the back of the mice. At the same time, the mice were exposed to 7 days of intermittent shaker stress. They were tested for ASR (100 dB and 120 dB stimuli) and PPI (70 dB + 100 dB and 70 dB + 120 dB) in the acoustic startle monitor system. The mice were assessed during the shaker stress on days 2 and 7 and 7, 14, 21 and 28 days after discontinuation of treatment. Separate groups of mice were tested in the open field in 15 min sessions on days 1, 3 and 6 during shaker stress and PB treatment. Exposure of mice to PB resulted in an exaggerated ASR, reduced PPI and non-significant decrease in locomotor activity. These behavioral changes were apparent only during exposure to PB. Repeated shaker stress did not have any effect on sensorimotor functions or open field behavior of mice. There was no prolonged or delayed effect of PB and/or stress on individual behavioral variables. The study found C57BL/6J mice to be behaviorally sensitive to PB treatment.

Survival analysis of liver transplant patients in Canada 1997-2002.

UNLABELLED: Liver transplantation is an important health care issue for Canadians. Very few studies have assessed survival and determinants of survival in liver transplant patients in Canada. METHODS: We carried out an epidemiological analysis of 1 year survival and determinants of 1 year survival in liver transplant patients, using Canadian Organ Replacement Registry data (1997-2002). Survival curves were plotted by the Kaplan-Meier method. Cox proportional hazards analysis was applied to evaluate hazard ratios with different age groups, gender, ethnicity, blood groups, donor type, pretransplantation medical status, and HBV infection status. RESULTS: A total of 1164 liver transplant patients were included in the analysis. One-year survival rate was 84.7%. Male recipients had a 21% higher risk of developing organ failure than females. Recipients over 60 years of age had a 5% lower survival probability in comparison with recipients below 20 years of age. Pacific Islanders and Aboriginals had 32% and 9% lower survival probabilities, respectively, in comparison with Caucasians. Type B blood recipients had a 12% higher survival probability, whereas type AB blood recipients had a 7% lower survival probability compared with type O blood recipients. Twenty-six live organ recipients had 40% higher survival probabilities than 1138 cadaveric organ recipients. Patients with fulminant hepatitis (status 3F) had the highest survival, while patients with fulminant failure in ICU with intubation/ventilation (status 4F) had the lowest survival. One hundred sixty-seven recipients with positive HBsAg antigen showed 10% lower survival probability than 997 cases with negative HBsAg antigen. CONCLUSION: In Canada, the first year survival rate is about 85%, which is comparable with other industrialized countries. Type of donor organs and recipient gender, ethnicity, ABO blood group, pretransplantation medical status, and HBV infection status had significant affects on the recipient survival.

Enhanced surveillance for childhood hepatitis B virus infection in Canada, 1999-2003.

Since hepatitis B virus (HBV) infection can have serious sequelae, especially if infection occurs during childhood, there is a continuing need to examine its epidemiology so as to inform control measures. We analyzed trends in disease incidence and patterns of hepatitis B virus (HBV) transmission in both Canadian-born and non-Canadian-born children from 1999 to 2003, through the Enhanced Hepatitis Strain Surveillance System. Amongst Canadian-born children, the incidence of newly identified HBV infection per 100,000 declined significantly during the study period from 1.4 in 1999, to 0.5 in 2003 (RR, 0.75 per year; 95% CI, 0.60-0.95). Amongst non-Canadian-born children, the incidence of HBV infection per 100,000 ranged from 9.4 to 16.3, during the study period (linear trend test, p=0.69). Poisson regression analysis revealed that non-Canadian-born children were more likely to have HBV infection (RR, 12.3; 95% CI, 7.6 to 19.8), than Canadian-born children. HBV infection was found to be more common among children emigrating from high endemic area, than among Canadian-born children. Current Canadian immunization policy should take into consideration the protection of all children against HBV infection, including those coming from countries where mass hepatitis B vaccination programs have still not been launched.

Pancreatic exocrine secretion in steers infused postruminally with casein and cornstarch.

Our objective was to evaluate the effect of postruminal protein infusion on pancreatic exocrine secretions. One Holstein, two crossbred, and five Angus steers (305 +/- 5 kg) with pancreatic pouch-duodenal reentrant cannulas and abomasal infusion catheters were used in a replicated 4 x 4 Latin square. All steers were abomasally infused with 1,050 g/d of raw cornstarch with treatments of 0, 60, 120, or 180 g/d of sodium casein suspended in water to yield 6,000 g/d of infusate daily. Steers were limit-fed (1.5 x NEm; 12 equal portions daily) a 90% corn silage, 10% supplement diet formulated to contain 12.5% CP. Periods consisted of 3 d of adaptation to infusion, 7 d of full infusion, 1 d of collection, and 7 d of rest. Pancreatic juice was collected in 30-min fractions continuously for 6 h. Total juice secreted and the pH of individual fractions were recorded, a 10% subsample was retained to form a composite sample, and remaining fluid was returned to the duodenum. Juice composite samples were stored (-30 degrees C) until analyzed for total protein and activities of alpha-amylase, trypsin, and chymotrypsin. Casein infusion linearly increased alpha-amylase concentration (182 to 271 units/mL; P < 0.02; 17.5 to 24.6 units/mg of protein; P < 0.03) and secretion rate (26,847 to 41,894 units/h; P < 0.01). Total juice secretion (155 g/h), pH of pancreatic juice (8.13), secretion rate of protein (1,536 mg/h), and concentration of protein (10.2 mg/mL) in pancreatic secretions were not affected (P > 0.05) by casein infusion. Similarly, casein infusion did not change 0.05) trypsin and chymotrypsin concentrations (1,379 and 349 units/L or 0.134 and 0.033 units/mg of protein, respectively) or secretion rates (206 and 52 units/h, respectively). Abomasal infusion of protein with starch stimulated a greater pancreatic secretion of alpha-amylase activity into the intestine than infusion of starch alone.

The evolution of methicillin-resistant Staphylococcus aureus in Canadian hospitals: 5 years of national surveillance.

BACKGROUND: To better understand the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Canadian hospitals, surveillance has been conducted in sentinel hospitals across the country since 1995. We report the results of the first 5 years of the program. METHODS: For each newly identified inpatient with MRSA, medical records were reviewed for demographic and clinical data. Isolates were subjected to susceptibility testing and molecular typing by pulsed-field gel electrophoresis. RESULTS: A total of 4507 patients infected or colonized with MRSA were identified between January 1995 and December 1999. The rate of MRSA increased each year from a mean of 0.95 per 100 S. aureus isolates in 1995 to 5.97 per 100 isolates in 1999 (0.46 per 1000 admissions in 1995 to 4.12 per 1000 admissions in 1999) (p < 0.05). Most of the increase in MRSA occurred in Ontario, Quebec and the western provinces. Of the 3009 cases for which the site of MRSA acquisition could be determined, 86% were acquired in a hospital, 8% were acquired in a long-term care facility and 6% were acquired in the community. A total of 1603 patients (36%) were infected with MRSA. The most common sites of infection were skin or soft tissue (25% of MRSA infections), pulmonary tissues (24%) and surgical sites (23%); 13% of the patients were bacteremic. An epidemiologic link with a previously identified MRSA patient was suspected in 53% of the cases. Molecular typing indicated that most (81%) of the isolates could be classified as related to 1 of the 4 Canadian epidemic strains of MRSA. INTERPRETATION: There has been a significant increase in the rate of isolating MRSA in many Canadian hospitals, related to the transmission of a relatively small number of MRSA strains.

Development of minimum criteria for the initiation of antibiotics in residents of long-term-care facilities: results of a consensus conference.

Establishing a clinical diagnosis of infection in residents of long-term-care facilities (LTCFs) is difficult. As a result, deciding when to initiate antibiotics can be particularly challenging. This article describes the establishment of minimum criteria for the initiation of antibiotics in residents of LTCFs. Experts in this area were invited to participate in a consensus conference. Using a modified delphi approach, a questionnaire and selected relevant articles were sent to participants who were asked to rank individual signs and symptoms with respect to their relative importance. Using the results of the weighting by participants, a modification of the nominal group process was used to achieve consensus. Criteria for initiating antibiotics for skin and soft-tissue infections, respiratory infections, urinary infections, and fever where the focus of infection is unknown were developed.

N-CDAD in Canada: results of the Canadian Nosocomial Infection Surveillance Program 1997 N-CDAD Prevalence Surveillance Project.

BACKGROUND: A 1996 preproject survey among Canadian Hospital Epidemiology Committee (CHEC) sites revealed variations in the prevention, detection, management and surveillance of Clostridium difficile-associated diarrhea (CDAD). Facilities wanted to establish national rates of nosocomially acquired CDAD (N-CDAD) to understand the impact of control or prevention measures, and the burden of N-CDAD on health care resources. The CHEC, in collaboration with the Laboratory Centre for Disease Control (Health Canada) and under the Canadian Nosocomial Infection Surveillance Program, undertook a prevalence surveillance project among selected hospitals throughout Canada. OBJECTIVE: To establish national prevalence rates of N-CDAD. METHODS: For six weeks in 1997, selected CHEC sites tested all diarrheal stools from inpatients for either C difficile toxin or C difficile bacteria with evidence of toxin production. Questionnaires were completed for patients with positive stool assays who met the case definitions. RESULTS: Nineteen health care facilities in eight provinces participated in the project. The overall prevalence of N-CDAD was 13.0% (95% CI 9.5% to 16.5%). The mean number of N-CDAD cases were 66.3 cases/100,000 patient days (95% CI 37.5 to 95.1) and 5.9 cases/1000 patient admissions (95% CI 3.4 to 8.4). N-CDAD was found most frequently in older patients and those who had been hospitalized for longer than two weeks in medical or surgical wards. CONCLUSIONS: This national prevalence surveillance project, which established N-CDAD rates, is useful as 'benchmark' data for Canadian health care facilities, and in understanding the patterns and impact of N-CDAD.

The emerging epidemiology of VRE in Canada: results of the CNISP Passive Reporting Network, 1994 to 1998.

OBJECTIVE: To provide a rapid and efficient means of collecting descriptive epidemiological data on occurrences of vancomycin-resistant enterococcus (VRE) in Canada. DESIGN AND METHODS: Passive reporting of data on individual or cluster occurrences of VRE using a one-page surveillance form. SETTING: The surveillance form was periodically distributed to all Canadian Hospital Epidemiology Committee members, Community and Hospital Infection Control Association members, L'Association des professionnels pour la prevention des infections members and provincial laboratories, representing 650 health care facilities across Canada. PATIENTS: Patients colonized or infected with VRE within Canadian health care facilities. RESULTS: Until the end of 1998, 263 reports of VRE were received from 113 health care facilities in 10 provinces, comprising a total of 1315 cases of VRE, with 1246 cases colonized (94.7%), 61 infected (4.6%)and eight of unknown status. (0.6%). VRE occurrences were reported in 56% of acute care teaching facilities and 38% of acute care community facilities. All facilities of more than 800 beds reported VRE occurences compared with only 10% of facilities with less than 200 beds (r2=0.86). Medical and surgical wards accounted for 51.4% of the reported VRE occurences. Sixty-five (24.7%) reports indicated an index case was from a foreign country, with 85.2% from the United States and 14.8% from other countries. Some type of screening was conducted in 50% of the sites. CONCLUSIONS: A VRE passive reporting network provided a rapid and efficient means of providing data on the evolving epidemiology of VRE in Canada.