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Background Gram-negative pathogens, such as Escherichia coli, are common causes of bloodstream infections (BSIs) and increasingly demonstrate antimicrobial resistance. Molecular rapid diagnostic tests (mRDTs) offer faster pathogen identification and susceptibility results, but higher costs compared with conventional methods. We determined the cost-effectiveness of the BioFire FilmArray Blood Culture Identification (BCID) Panel, as a type of mRDT, compared with conventional methods in the identification of E. coli BSIs. Methods We constructed a decision analytic model comparing BCID with conventional methods in the identification and susceptibility testing of hospitalized patients with E. coli BSIs from the perspective of the public healthcare payer. Model inputs were obtained from published literature. Cost-effectiveness was calculated by determining the per-patient admission cost, the QALYs garnered and the incremental cost-effectiveness ratios (ICERs) where applicable. Monte Carlo probabilistic sensitivity analyses and one-way sensitivity analyses were conducted to assess the robustness of the model. All costs reflect 2019 Canadian dollars. Results The Monte Carlo probabilistic analyses resulted in cost savings ($27 070.83 versus $35 649.81) and improved QALYs (8.65 versus 7.10) in favour of BCID. At a willingness to pay up to $100 000, BCID had a 72.6%–83.8% chance of being cost-effective. One-way sensitivity analyses revealed length of stay and cost per day of hospitalization to have the most substantial impact on costs and QALYs. Conclusions BCID was found to be cost-saving when used to diagnose E. coli BSI compared with conventional testing. Cost savings were most influenced by length of stay and cost per day of hospitalization.

Objective:To evaluate the cost of 1-stage and 2-stage revisions, debridement, antibiotic and implant retention (DAIR) and DAIR with liner exchange for complex surgical site infections (SSIs) following hip and knee replacements.Design:Retrospective population-based economic analysis of patients undergoing intervention for SSIs between April 1, 2012 and March 31, 2019.Setting:The study was conducted in the Calgary zone of Alberta Health Services (AHS) in Canada.Participants:Individuals >18 years with complex SSI following hip or knee replacement.Methods:Patients with complex SSIs were identified using the AHS infection prevention and control database. A combination of microcosting and gross costing methods were used to estimate 12- and 24-month costs following the initial hospital admission for arthroplasty. Subgroup, inverse Gaussian and γ regression analyses were used to evaluate the impact of age and comorbidities on cost.Results:In total, 142 patients with complex SSIs were identified, with a mean age of 66.8 years. Total direct medical costs in United States dollars of 2-stage revisions were ($100,992 (95% CI, 34,587–167,396) at 12 months. The 1-stage revision ($41,176; 95% CI, 23,361–58,991), DAIR with liner exchange ($41,267; 95% CI, 29,923–52,612) and DAIR ($46,605; 95% CI, 15,277–76,844) were associated with fewer costs at 12 months. Age >65 years and chronic complications of diabetes and hypertension were associated with increased costs in subgroup and regression analysis.Conclusions:Medical costs are highest at 12 months and for 2-stage revisions in hip and knee complex SSI cases. Further work should explore surgical outcomes correlated with costs to enhance patient care.

Objective Surgical site infections (SSIs) are a serious and costly post-op complication. Generating SSI rates often requires labor-intensive methods, but increasing numbers of publications reported SSI rates using administrative data. Methods Index laminectomy and spinal fusion procedures were identified using Canadian Classification of Health Interventions (CCI) procedure codes for inpatients and outpatients in the province of Alberta, Canada between 2008 and 2015. SSIs occurring in the year postsurgery were identified using the International Classification of Diseases, 10th Revision, Canada (ICD-10-CA) diagnosis and CCI procedure codes indicative of post-op infection. Rates of SSIs and case characteristics were reported. Results Over the 8-year study period, 21,222 index spinal procedures were identified of which 12,027 (56.7%) were laminectomy procedures, with 322 SSIs identified, an SSI rate of 2.7 per 100 procedures. Of the 9,195 (43.3%) fusion procedures, 298 were identified as an SSI, an SSI rate of 3.2 per 100 procedures. This study found SSI rates increased from 2008 and 2015, and rates were the highest in the 0-18 year age group. Conclusions The rates reported in this study were similar to published SSI rates using traditional surveillance methods, suggesting administrative data may be a viable method for reporting SSI rates following spinal procedures. Further work is needed to validate SSIs identified using administrative data by comparing to traditional surveillance.

Background Clostridioides difficile infection (CDI) is one of the most common health care-associated infections. This study assessed the validity of the Discharge Abstract Database (DAD) compared to a traditional clinical surveillance method for identifying CDI. Methods Retrospective analysis of all DAD records with International Statistical Classification of Diseases and Related Health Problems 10th Revision (ie, ICD-10) diagnostic code A04.7 (enterocolitis due to CDI) between April 2015 and March 2019 were compared to a clinical dataset of positive inpatient CDI for all acute care facilities in Alberta, Canada. Sensitivity and positive predictive values were calculated using R version 3.6.0. Results The DAD had a sensitivity of 85.0% (95% confidence interval: 84.1%-85.8%) and a positive predictive value of 80.0% (95% confidence interval: 79.2%-80.0%). The CDI rate per 1,000 admissions over the study period was 28% higher in the DAD compared to Infection Prevention and Control surveillance. Discussion The DAD does not distinguish symptomatic cases from asymptomatic cases and so indicators to identify symptomatic disease would need to be applied, potentially through a linkage to antibiotic treatment orders available in patient management systems. Conclusions The DAD is moderately sensitive for identifying symptomatic CDI cases in Alberta, Canada and caution should be applied when interpreting rates based on administrative data.

Objective:Adverse outcomes following Clostridioides difficile infection (CDI) are not often reported for long-term care facility (LTCF) residents. We focused on the adverse outcomes due to CDI identified in Alberta LTCFs.Methods:All positive Clostridioides difficile stool specimens identified by laboratory-identified (LabID) event surveillance in Alberta from 2011 to 2018, along with Alberta Continuing Care Information System, were used to define CDI in Alberta LTCFs. CDI cases were classified as long-term care onset, hospital onset, and community onset. Laboratory records were linked to provincial databases to analyze acute-care admissions and mortality within 30-day post CDI. Age, sex, case classification, episode, and operator type, were investigated using logistic regression.Results:Overall, 902 CDI cases were identified in 762 LTCF residents. Of all CDI events, 860 (95.3%) were long-term care onset, 38 (4.2%) were hospital onset, and 4 (0.4%) were community onset. The CDI rate was 2.0 of 100,000 resident days. In total, 157 residents (20.6%) had 30-day all-cause mortality, 126 CDI cases (14.0%) had 30-day all-cause acute-care admissions. The 30-day all-cause mortality rate was significantly higher in residents aged >80 versus ≤80 years (24.9 vs 12.3 per 100 residents; P < .05). Residents aged >80 years, with hospital-onset CDI, and those staying in private or voluntary LTCFs were more likely to have 30-day all-cause acute-care admissions.Conclusions:The prevalence of CDI adverse outcomes is in LTCFs was found to be high using LabID event surveillance. Annual review of CDI adverse outcomes using LabID event can minimize the burden of surveillance and standardize the process across all Alberta LTCFs.

1ABSTRACTObjectivesTo review the literature from 2011 until March 31st, 2020 to identify the risk of transmission of ARIs to healthcare workers caring for patients undergoing AGMPs compared with the risk of transmission when caring for patients not undergoing AGMPs.ResultsOnly two prospective cohort studies were identified meeting inclusion criteria. One found that performance or assistance with AGMP during the previous week was significantly associated with symptomatic influenza (adjusted OR: 2.29, 95% CI: 1.3 to 4.2). The second study found that performance of AGMP was significantly associated with clinical respiratory infections (RR 2.9, 95% CI 1.42-5.87, p

In a population-based, five-year retrospective cohort study of 5304 adult patients with hospital-acquired Clostridioides difficile infection across Alberta (N=101 hospitals), 30-day all-cause and attributable mortality were 12.2% and 4.5%, respectively. Patients >75 years of age had the highest odds of attributable mortality (odds ratio (OR) 9.34, 95% confidence interval (CI) 2.92-29.83) and largest difference in mean length of stay (11.7 days, 95% CI 8.2-15.2). A novel finding was that elevated white blood cell count at admission was associated with reduced attributable mortality (OR 0.67, 95% CI 0.50-0.90) which deserves further study. Advancing age was incrementally and significantly associated with all outcomes.

Objective:To determine the attributable cost and length of stay of hospital-acquired Clostridioides difficile infection (HA-CDI) from the healthcare payer perspective using linked clinical, administrative, and microcosting data.Design:A retrospective, population-based, propensity-score–matched cohort study.Setting:Acute-care facilities in Alberta, Canada.Patients:Admitted adult (≥18 years) patients with incident HA-CDI and without CDI between April 1, 2012, and March 31, 2016.Methods:Incident cases of HA-CDI were identified using a clinical surveillance definition. Cases were matched to noncases of CDI (those without a positive C. difficile test or without clinical CDI) on propensity score and exposure time. The outcomes were attributable costs and length of stay of the hospitalization where the CDI was identified. Costs were expressed in 2018 Canadian dollars.Results:Of the 2,916 HA-CDI cases at facilities with microcosting data available, 98.4% were matched to 13,024 noncases of CDI. The total adjusted cost among HA-CDI cases was 27% greater than noncases of CDI (ratio, 1.27; 95% confidence interval [CI], 1.21–1.33). The mean attributable cost was $18,386 (CAD 2018; USD $14,190; 95% CI, $14,312–$22,460; USD $11,046-$17,334). The adjusted length of stay among HA-CDI cases was 13% greater than for noncases of CDI (ratio, 1.13; 95% CI, 1.07–1.19), which corresponds to an extra 5.6 days (95% CI, 3.10–8.06) in length of hospital stay per HA-CDI case.Conclusions:In this population-based, propensity score matched analysis using microcosting data, HA-CDI was associated with substantial attributable cost.

SARS-CoV-2 has been detected in wastewater and its abundance correlated with community COVID-19 cases, hospitalizations and deaths. We sought to use wastewater-based detection of SARS-CoV-2 to assess the epidemiology of SARS-CoV-2 in hospitals. Between August and December 2020, twice-weekly wastewater samples from three tertiary-care hospitals (totaling >2100 dedicated inpatient beds) were collected. Hospital-1 and Hospital-2 could be captured with a single sampling point whereas Hospital-3 required three separate monitoring sites. Wastewater samples were concentrated and cleaned using the 4S-silica column method and assessed for SARS-CoV-2 gene-targets (N1, N2 and E) and controls using RT-qPCR. Wastewater SARS-CoV-2 as measured by quantification cycle (Cq), genome copies and genomes normalized to the fecal biomarker PMMoV were compared to the total daily number of patients hospitalized with active COVID-19, confirmed cases of hospital-acquired infection, and the occurrence of unit-specific outbreaks. Of 165 wastewater samples collected, 159 (96%) were assayable. The N1-gene from SARS-CoV-2 was detected in 64.1% of samples, N2 in 49.7% and E in 10%. N1 and N2 in wastewater increased over time both in terms of the amount of detectable virus and the proportion of samples that were positive, consistent with increasing hospitalizations at those sites with single monitoring points (Pearson's r=0.679, P, Graphical Abstract Image, graphical abstract

Background As a result of the novel coronavirus disease 2019 (COVID-19), there have been widespread changes in healthcare access. We conducted a retrospective population-based study in Alberta, Canada (population 4.4 million), where there have been approximately 1550 hospital admissions for COVID-19, to determine the impact of COVID-19 on hospital admissions and emergency department (ED visits), following initiation of a public health emergency act on March 15, 2020. Methods We used multivariable negative binomial regression models to compare daily numbers of medical/surgical hospital admissions via the ED between March 16-September 23, 2019 (pre COVID-19) and March 16-September 23, 2020 (post COVID-19 public health measures). We compared the most frequent diagnoses for hospital admissions pre/post COVID-19 public health measures. A similar analysis was completed for numbers of daily ED visits for any reason with a particular focus on ambulatory care sensitive conditions (ACSC). Findings There was a significant reduction in both daily medical (incident rate ratio (IRR) 0.86, p Conclusions Despite a relatively low volume of COVID-19 hospital admissions in Alberta, there was an extensive impact on our healthcare system with fewer admissions to hospital and ED visits. This work generates hypotheses around causes for reduced hospital admissions and ED visits which warrant further investigation. As most publicly funded health systems struggle with health-system capacity routinely, understanding how these reductions can be safely sustained will be critical.

BackgroundSARS-CoV-2 has been detected in wastewater and its abundance correlated with community COVID-19 cases, hospitalizations and deaths. We sought to use wastewater-based detection of SARS-CoV-2 to assess the epidemiology of SARS-CoV-2 in hospitals.MethodsBetween August and December 2020, twice-weekly wastewater samples from three tertiary-care hospitals (totaling >2100 dedicated inpatient beds) were collected. Wastewater samples were concentrated and cleaned using the 4S-silica column method and assessed for SARS-CoV-2 gene-targets (N1, N2 and E) and controls using RT-qPCR. Wastewater SARS-CoV-2 as measured by quantification cycle (Cq), genome copies and genomes normalized to the fecal biomarker PMMoV were compared to the total daily number of patients hospitalized with active COVID-19, confirmed cases of hospital-acquired infection, and the occurrence of unit-specific outbreaks.ResultsOf 165 wastewater samples collected, 159 (96%) were assayable. The N1-gene from SARS-CoV-2 was detected in 64.1% of samples, N2 in 49.7% and E in 10%. N1 and N2 in wastewater increased over time both in terms of amount of detectable virus and the proportion of samples that were positive, consistent with increasing hospitalizations (Pearson’s r=0.679, PConclusionsWastewater-based monitoring of SARS-CoV-2 represents a promising tool for SARS-CoV-2 passive surveillance and case identification, containment, and mitigation in acute-care medical facilities.Supplemental Material includedKey-points summarySAS-CoV-2 RNA is detectable in hospital wastewater. Wastewater SARS-CoV-2 RNA increases in conjunction with COVID-19-related hospitalizations. Spikes in SARS-CoV-2 wastewater signal correspond to incident hospital-acquired cases and outbreaks, suggesting passive surveillance via wastewater has great promise for COVID-19 monitoring.

AimsRecent evidence suggests that an antibiotic impregnated envelope inserted at time of cardiac implantable electronic device (CIED) implantation may reduce risk of subsequent CIED infection compared with standard of care (SoC). The objective of the current work was to perform a cost-effectiveness analysis comparing an antibiotic impregnated envelope with SoC at time of CIED insertion.Methods and resultsDecision analytic models were used to project healthcare costs and benefits of two strategies, an antibiotic impregnated envelope plus SoC (Env+SoC) vs. SoC alone, in a cohort of patients undergoing CIED implantation over a 1-year time horizon. Evidence from published literature informed the model inputs. Probabilistic and deterministic sensitivity analyses were performed. The primary outcome was the incremental cost per infection prevented, assessed from the Canadian healthcare system perspective. Envelope plus SoC was associated with fewer CIED infection (7 CIED infections/1000 patients) at higher total costs ($29 033 000/1000 patients) compared with SoC (11 CIED infections and $27 926 000/1000 patients). The incremental cost per infection prevented over 1 year was $274 416. Use of Env+SoC was cost saving only when baseline CIED infection risk was increased to 6% (vs. base case of 1.2%).ConclusionsA strategy of Env+SoC was not economically favourable compared with SoC alone, and the opportunity cost of widescale implementation should be considered. Future work is required to develop validated risk stratification tools to identify patients at greatest risk of CIED infection. The value proposition of Env+SoC improves when applying this intervention to patients at greatest infection risk.

Background: Microbial invasion of the bloodstream is associated with a major burden of illness. Despite its importance, there is inconsistency in utilization of terms used to define it. Objective: To characterize the contemporary use of terms to define microbial invasion of the bloodstream for surveillance and research purposes. Methods: Structured review of publications reported from 2000 to 2019. Results: The search strategy retrieved 10,095 citations of which bloodstream infection, bacteraemia and fungaemia were included in 2813, 6900 and 1054 articles, respectively. There was a tripling of the number of annual citations during the study and although bacteraemia was most frequent, there was a progressive increase in the use of the term bloodstream infection. Among the 100 reports randomly selected for detailed review, the terms bacteraemia, bloodstream infection and fungaemia were used in 57, 51 and 19 publications, respectively. Explicit definitions for bloodstream infection (26/51; 51%), bacteraemia (13/57; 23%) and fungaemia (7/19; 37%) were included in reports where these terms were used. Although nearly all (95%) of the studies indicated a positive blood culture as an inclusion criteria and/or definition, only a minority indicated means to exclude contaminants (33%) or specific attributes to support clinical significance (38%). Use of explicit definitions was more common among reports that exclusively used the term bloodstream infection as compared to bacteraemia. Conclusions: Terms have been inconsistently defined and imprecisely used to refer to microbial invasion of the bloodstream. Clinically relevant and objective definitions that are widely acceptable are needed for surveillance and research purposes.

Background:Clostridioides difficile infection (CDI) is the most common cause of infectious diarrhea in hospitalized patients. Probiotics have been studied as a measure to prevent CDI. Timely probiotic administration to at-risk patients receiving systemic antimicrobials presents significant challenges. We sought to determine optimal implementation methods to administer probiotics to all adult inpatients aged 55 years receiving a course of systemic antimicrobials across an entire health region. Methods: Using a randomized stepped-wedge design across 4 acute-care hospitals (n = 2,490 beds), the probiotic Bio-K+ was prescribed daily to patients receiving systemic antimicrobials and was continued for 5 days after antimicrobial discontinuation. Focus groups and interviews were conducted to identify barriers, and the implementation strategy was adapted to address the key identified barriers. The implementation strategy included clinical decision support involving a linked flag on antibiotic ordering and a 1-click order entry within the electronic medical record (EMR), provider and patient education (written/videos/in-person), and local site champions. Protocol adherence was measured by tracking the number of patients on therapeutic antimicrobials that received BioK+ based on the bedside nursing EMR medication administration records. Adherence rates were sorted by hospital and unit in 48- and 72-hour intervals with recording of percentile distribution of time (days) to receipt of the first antimicrobial. Results: In total, 340 education sessions with >1,800 key stakeholders occurred before and during implementation across the 4 involved hospitals. The overall adherence of probiotic ordering for wards with antimicrobial orders was 78% and 80% at 48 and 72 hours, respectively over 72 patient months. Individual hospital adherence rates varied between 77% and 80% at 48 hours and between 79% and 83% at 72 hours. Of 246,144 scheduled probiotic orders, 94% were administered at the bedside within a median of 0.61 days (75th percentile, 0.88), 0.47 days (75th percentile, 0.86), 0.71 days (75th percentile, 0.92) and 0.67 days (75th percentile, 0.93), respectively, at the 4 sites after receipt of first antimicrobial. The key themes from the focus groups emphasized the usefulness of the linked flag alert for probiotics on antibiotic ordering, the ease of the EMR 1-click order entry, and the importance of the education sessions. Conclusions: Electronic clinical decision support, education, and local champion support achieved a high implementation rate consistent across all sites. Use of a 1-click order entry in the EMR was considered a key component of the success of the implementation and should be considered for any implementation strategy for a stewardship initiative. Achieving high prescribing adherence allows more precision in evaluating the effectiveness of the probiotic strategy.Funding: Partnerships for Research and Innovation in the Health System, Alberta Innovates/Health Solutions Funding: AwardDisclosures: None

Background: Hospital-acquired Clostridioides difficile infection (HA-CDI) rates are highly variable over time, posing problems for research assessing interventions that might improve rates. By understanding seasonality in HA-CDI rates and the impacts that other factors such as influenza admissions might have on these rates, we can account for them when establishing the relationship between interventions and infection rates. We assessed whether there were seasonal trends in HA-CDI and whether they could be accounted for by influenza rates. Methods: We assessed HA-CDI rates per 10,000 patient days, and the rate of hospitalized patients with influenza per 1,000 admissions in 4 acute-care facilities (n = 2,490 beds) in Calgary, Alberta, from January 2016 to December 2018. We used 4 statistical approaches in R (version 3.5.1 software): (1) autoregressive integrated moving average (ARIMA) to assess dependencies and trends in each of the monthly HA-CDI and influenza series; (2) cross correlation to assess dependencies between the HA-CDI and influenza series lagged over time; (3) Poisson harmonic regression models (with sine and cosine components) to assess the seasonality of the rates; and (4) Poisson regression to determine whether influenza rates accounted for seasonality in the HA-CDI rates. Results: Conventional ARIMA approaches did not detect seasonality in the HA-CDI rates, but we found strong seasonality in the influenza rates. A cross-correlation analysis revealed evidence of correlation between the series at a lag of zero (R = 0.41; 95% CI, 0.10–0.65) and provided an indication of a seasonal relationship between the series (Fig. 1). Poisson regression suggested that influenza rates predicted CDI rates (P < .01). Using harmonic regression, there was evidence of seasonality in HA-CDI rates (2 [2 df] = 6.62; P < .05) and influenza rates (2 [2 df] = 1,796.6; P < .001). In a Poisson model of HA-CDI rates with both the harmonic components and influenza admission rates, the harmonic components were no longer predictive of HA-CDI rates. Conclusions: Harmonic regression provided a sensitive means of identifying seasonality in HA-CDI rates, but the seasonality effect was accounted for by influenza admission rates. The relationship between HA-CDI and influenza rates is likely mediated by antibiotic prescriptions, which needs to be assessed. To improve precision and reduce bias, research on interventions to reduce HA-CDI rates should assess historic seasonality in HA-CDI rates and should account for influenza admissions.Funding: NoneDisclosures: None

Impact of isolation precautions on psychological wellbeing of patients has yet to be fully quantified. To assess the impact of isolation precautions on patients' health-related quality of life and depression or anxiety scales and estimate per day cost of anxiety and depression. Literature pertaining to impact of isolation precautions was searched on EMBASE and PubMed databases and Google Scholar. A two-step independent screening of the articles was performed. Articles that compared isolated and non-isolated patients using different quality of life and psychological burden scales were included. A meta-analysis was conducted using the Hospital Anxiety and Depression Scales (HADS-A and HADS-D). Psychological burden measures from selected literature were presented in a graph as effect sizes. Per day cost of anxiety and depression was estimated using pooled mean difference from meta-analysis. Out of 106 articles, 94 were excluded due to inclusion criteria, leaving 12 for full text review. After review of full text of the articles, seven articles were shortlisted for empirical analysis and four out of these seven for meta-analysis. The pooled mean difference estimates for HADS-A was -1.4 (P=0.15) and that for HADS-D was -1.85 (P=0.09). In the empirical analysis of psychological burden scales, the effect in all studies except one was negative. Results from meta-analysis and empirical analysis of psychological burden implied that isolated patients are worse off in general. The implied estimated per day cost of anxiety and depression in terms of quality-adjusted life years (QALYs) is approximately US$10.

Background Clostridioides difficile infection (CDI) is one of the most common health care–associated infections. This study assessed the validity of a laboratory-based surveillance method as compared with a traditional, clinical surveillance method to identify hospital-acquired CDIs. Methods Retrospective analysis of positive C difficile laboratory records between April 2015 and March 2017 were compared with a clinical dataset of positive inpatient C difficile cases for all acute care facilities in Alberta, Canada. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated using STATA/IC 13.0. Results The laboratory surveillance method had a sensitivity of 96.6% (95% confidence interval [CI], 95.7%-97.3%) and a specificity of 65.7% (95% CI, 63.6%-67.8%); positive predictive value and negative predictive value were 74.3% (95% CI, 73.2%-75.5%) and 94.9% (95% CI, 93.7%-95.9%), respectively. Discussion To date, the breadth of research on alternate CDI surveillance systems has focused on the use of International Statistical Classification of Diseases and Related Health Problems 9th and 10th Revision coding mechanisms. Our results expand on the published literature, as a laboratory approach may provide more timely information, with a smaller amount of misclassified cases. Conclusions Using a laboratory surveillance method to capture hospital-acquired CDI cases is highly sensitive but not overly specific. Changes to improve the specificity of this method are provided.

SUMMARYPatients with methicillin-resistant Staphylococcus aureus (MRSA) clones, which were traditionally seen in the community setting (USA400/CMRSA7 and USA300/CMRSA10), are often identified as hospital-acquired (HA) infections using Infection Prevention and Control (IPC) surveillance definitions. This study examined the demographics and healthcare risk factors of patients with HA-MRSA to help understand if community MRSA clones are from a source internal or external to the hospital setting. Despite USA300/CMRSA10 being the predominant clone in Alberta, hospital clones (USA100/CMRSA2) still dominated in the acute care setting. In the Alberta hospitalized population, patients with USA400/CMRSA7 and USA300/CMRSA10 clones were significantly younger, had fewer comorbidities, and a greater proportion had none or ambulatory care-only healthcare exposure. These findings suggest that there are two distinct populations of HA-MRSA patients, and the patients with USA400/CMRSA7 and USA300/CMRSA10 clones identified in hospital more greatly resemble patients affected by those clones in the community. It is possible that epidemiological assessment overidentifies HA acquisition of MRSA in patients unscreened for MRSA on admission to acute care.

Background Recurrent surgical site infections (SSIs) are associated with decreased quality of life for patients and increased economic burden to healthcare systems. Positive cultures at reimplantation and patient co-morbidities have been shown to increase the risk of recurrent SSI in hip and knee surgical site infections. Two-stage exchange has been considered for the most appropriate surgical management for these SSI’s, however, it is unclear whether the type of revision arthroplasty and pathogen of the first SSI impacts recurrence rates. Methods A retrospective review of prospectively collected data on all complex SSIs following primary hip and knee arthroplasties between April 1 2012 and March 31, 2019, in Calgary, Alberta was performed. Patients were followed for two years post-index arthroplasty to determine initial management of first complex SSI (Debridement, antibiotics and implant retention (DAIR) vs DAIR+liner exchange vs one-stage vs two-stage), rate of recurrent complex SSI, and microbiological data for first and subsequent SSI’s. Results Of the 142 complex SSIs, 95 (66.9%) were managed with DAIR and liner exchange, 25 (17.6%) were managed with DAIR, 13 (9.1%) with one-stage and 8 (5.6%) with two-stage procedures. The recurrence rate was 19/95 (20%) for DAIR and liner, 8/25 (32%) for DAIR alone, 2/13 (15%) with one stage, and 3/8 (37.5%) with two-stage. There was no significant difference in recurrence rates of complex SSI when stratified by surgical management. Of the pathogens, Staphylococcus aureus (S.aureus) (including methicillin-resistant S. aureus (MRSA)) accounted for 35.2% of total first SSI and 50% of recurrences. A significantly higher proportion of S.aureus infections (including MRSA) ended up with a recurrent infection compared to all other pathogens (p=0.045). Of the 32 recurrences, 28.1% were due to the same pathogen as the initial SSI. Conclusion S.aureus was the most common pathogen causing initial and recurrent SSIs. This reinforces that S.aureus complex SSIs would likely benefit from early recognition and aggressive treatment. Recurrence of SSI was not impacted by type of revision arthroplasty. This study is limited by a small sample size. These findings contribute to the paucity of literature in this area and suggest a need for expansion to larger populations. Disclosures All Authors: No reported disclosures

Background: Infection Prevention and Control (IPC) for Alberta Health Services and Covenant Health in the province of Alberta, Canada conducts surveillance for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) on all individuals admitted to acute-care and acute tertiary-care rehabilitation care facilities. Objective: The objective of this study was to determine the consistency and accuracy of infection decisions for MRSA and VRE. Methods: Surveillance cases of antibiotic-resistant organisms (AROs) collected using the provincial data entry surveillance platform between April 1, 2015, and March 31, 2017, across the province were reabstracted by infection control professionals and physicians using the NHSN infection definitions and compared to the original case severity decisions. Interrater agreement (Cohen’s ) and validity (sensitivity, specificity and predictive values) were calculated to compare the original and reabstracted infection decisions. Results: Collectively, 97% (87 of 90) of the IPC program staff and physicians who were initially invited re-abstracted 264 MRSA cases and 103 VRE cases within the review period. Provincially, 20% of the ARO cases reviewed (74 of 367) differed from the original infection decision. Among these 74 cases, 46 cases (34 MRSA and 12 VRE cases) changed from infection (original decision) to colonization (reabstracted decision) and 28 cases (21 MRSA and 7 VRE cases) changed from colonization to infection. The Cohen values for MRSA and VRE were 0.55 and 0.56, respectively, suggesting a moderate level of agreement for decisions made among IPC program staff. The sensitivity of the infection decision was higher with MRSA (86.5%) than for VRE (74.1%), meaning that there were more MRSA cases than VRE cases classified as infection in the original decision that remained infection following the review. Conclusions: Observed discordances on infection decisions were identified and may be attributed (1) to variations in the interpretation of the NHSN definitions, (2) to additional information that may have been available in the re-abstracted review compared to the original review, or (3) a difference in the information that was accessed to perform the original review compared to the reabstraction. This data-quality review provided an opportunity for IPC staff and physicians to become more familiar with infection definitions and such reviews will continue to be a regular process used to assess data quality within the IPC department.Funding: NoneDisclosures: None

Background The objective of this review is to provide a comprehensive overview of the different types of economic evaluations that can be utilized by Infection Prevention and Control practitioners with a particular focus on the use of the quality adjusted life year, and its associated challenges. We also highlight existing economic evaluations published within Infection Prevention and Control, research gaps and future directions. Design Narrative Review. Conclusions To date the majority of economic evaluations within Infection Prevention and Control are considered partial economic evaluations. Acknowledging the challenges, which include variable utilities within infection prevention and control, a lack of randomized controlled trials, and difficulty in modelling infectious diseases in general, future economic evaluation studies should strive to be consistent with published guidelines for economic evaluations. This includes the use of quality adjusted life years. Further research is required to estimate utility scores of relevance within Infection Prevention and Control.

Background The rates of antimicrobial-resistant organisms (ARO) continue to increase for both hospitalized and community patients. Few resources have been allocated to reduce the spread of resistance on global, national and local levels, in part because the broader economic impact of antimicrobial resistance (i.e. the externality) is not fully considered when determining how much to invest to prevent AROs, including strategies to contain antimicrobial resistance, such as antimicrobial stewardship programs. To determine how best to measure and incorporate the impact of externalities associated with the antimicrobial resistance when making resource allocation decisions aimed to reduce antimicrobial resistance within healthcare facilities, we reviewed the literature to identify publications which 1) described the externalities of antimicrobial resistance, 2) described approaches to quantifying the externalities associated with antimicrobial resistance or 3) described macro-level policy options to consider the impact of externalities. Medline was reviewed to identify published studies up to September 2016. Main body An externality is a cost or a benefit associated with one person’s activity that impacts others who did not choose to incur that cost or benefit. We did not identify a well-accepted method of accurately quantifying the externality associated with antimicrobial resistance. We did identify three main methods that have gained popularity to try to take into account the externalities of antimicrobial resistance, including regulation, charges or taxes on the use of antimicrobials, and the right to trade permits or licenses for antimicrobial use. To our knowledge, regulating use of antimicrobials is the only strategy currently being used by health care systems to reduce antimicrobial use, and thereby reduce AROs. To justify expenditures on programs that reduce AROs (i.e. to formally incorporate the impact of the negative externality of antimicrobial resistance associated with antimicrobial use), we propose an alternative approach that quantifies the externalities of antimicrobial use, combining the attributable cost of AROs with time-series analyses showing the relationship between antimicrobial utilization and incidence of AROs. Conclusion Based on the findings of this review, we propose a methodology that healthcare organizations can use to incorporate the impact of negative externalities when making resource allocation decisions on strategies to reduce AROs. Electronic supplementary material The online version of this article (doi:10.1186/s13756-017-0211-2) contains supplementary material, which is available to authorized users.

Co-morbid illnesses have a major influence on the epidemiology of infectious diseases. Although International Classification of Diseases (ICD) discharge codes are frequently used to evaluate the presence of co-morbidities in observational research, additional research is required about their validity. We reviewed the evidence supporting the use of routinely coded administrative data for ascertainment of co-morbid diseases with emphasis as it relates to the study of infectious diseases. A systematic Medline, Embase, and bibliographic review were conducted in order to identify and critically appraise published (1990–2008) studies comparing administrative databases with conventional chart review. Twenty-one co-morbidities commonly associated with infectious diseases risk were a priori selected for specific evaluation. Of the 21 co-morbid conditions chosen, only 19 had adequate data available for evaluation. Thirteen studies were included; only one focused on an infectious disease population. Eleven articles validated individual co-morbid conditions data in electronic administrative databases and reported a wide range of pooled sensitivity (13–82%) but overall high pooled specificity (>97%) when compared with medical chart review. Seven articles compared Charlson Co-morbidity Index scores derived from administrative data algorithms as compared with that calculated from medical record review and found that administrative data underscored the index in all articles with kappa agreement ranging from 0.30 to 0.56. The small body of literature published to date suggests that electronic administrative databases have limited validity for co-morbidity evaluation. Studies evaluating administrative database ascertainment of co-morbidities specifically in infectious diseases research are needed.

Objectives: The administration of 1 to 2 doses of intravenous (IV) antibiotics in the emergency department (ED) followed by discharge on oral antibiotics has become a treatment option for children with cellulitis, despite an absence of evidence supporting this practice. The objective of this study was to determine the failure rate of ED short-course IV antibiotic therapy (IV-short course). Methods: This retrospective study included children aged 0 to 18 years diagnosed with cellulitis in a pediatric ED during the 2005 calendar year. Treatment was categorized as (a) discharge on outpatient oral antibiotics, (b) IV-short course, or (c) admission for IV antibiotics (IV-admit). Failure was defined by a subsequent visit less than 7 days since the index visit with a change in antibiotic treatment, the administration of IV antibiotics, or hospitalization. A second data abstractor reviewed 10% of the charts to allow calculation of interobserver scores. Results: There were 321 eligible children, of whom 154 children were treated with oral antibiotics, 85 IV-short course, and 82 IV-admit. A total of 23 patients (7%) met criteria for failure. Compared with IV-admit, the odds ratio of failure among those who received IV-short course was 7.2 (95% confidence interval [CI], 1.6-33.1). Those who received IV-short course were more likely to revisit within 7 days than were children treated with oral antibiotics alone (risk ratio, 2.4; 95% CI, 1.2-4.7); however, revisits were no more frequent than among children in the IV-admit group (risk ratio, 2.8; 95% CI, 0.65-12.1). The total mean duration of hospital stay was significantly less in the IV-short course group compared with the IV-admit group (14.9 vs 118.6 hours; P < 0.001). Conclusions: Children with cellulitis frequently receive IV antibiotics. Short-course IV antibiotic therapy is associated with a high failure rate and prolonged ED stay compared with those in children treated with oral antibiotics alone. However, their clinical similarity to the IV-admit group, shorter length of hospital stay, but high failure rate mandates further evaluation before widespread adoption.

Electronic surveillance that utilises information held in databases is more efficient than conventional infection surveillance methods. Validity is not well-defined, however. We systematically reviewed studies comparing the utility of electronic and conventional surveillance methods. Publications were identified using Medline (1980-2007) and bibliographic review. The sensitivity and specificity of electronic compared with conventional surveillance was reported. Twenty-four studies were included. Six studies reported that nosocomial infections could be detected utilising microbiology data alone with good overall sensitivity (range: 63-91%) and excellent specificity (range: 87 to >99%). Two studies used three laboratory-based algorithms for the detection of infection outbreaks yielding variable utility measures (sensitivity, range: 43-91%; specificity, range: 67-86%). Seven studies using only administrative data including discharge coding (International Classification of Diseases, 9th edn, Clinical Modification) and pharmacy data claimed databases had good sensitivity (range: 59-96%) and excellent specificity (range: 95 to >99%) in detecting nosocomial infections. Six studies combined both laboratory and administrative data for a range of infections, and overall had higher sensitivity (range: 71-94%) but lower specificity (range: 47 to >99%) than with use of either alone. Three studies evaluated community-acquired infections with variable results. Electronic surveillance has moderate to excellent utility compared with conventional methods for nosocomial infections. Future studies are needed to refine electronic algorithms further, especially with community-onset infections.

Background. Electronic surveillance systems (ESSs) that utilize existing information in databases are more efficient than conventional infection surveillance methods. The objective was to assess an ESS for bloodstream infections (BSIs) in the Calgary Zone for its agreement with traditional medical record review.Methods. The ESS was developed by linking related data from regional laboratory and hospital administrative databases and using set definitions for excluding contaminants and duplicate isolates. Infections were classified as hospital-acquired (HA), healthcare-associated community-onset (HCA), or community-acquired (CA). A random sample of patients from the ESS was then compared with independent medical record review.Results. Among the 308 patients selected for comparative review, the ESS identified 318 episodes of BSI of which 130 (40.9%) were CA, 98 (30.8%) were HCA, and 90 (28.3%) were HA. Medical record review identified 313 episodes of which 136 (43.4%) were CA, 97 (30.9%) were HCA, and 80 (25.6%) were HA. Episodes of BSI were concordant in 304 (97%) cases. Overall, there was 85.5% agreement between ESS and medical record review for the classification of where BSIs were acquired (kappa = 0.78, 95% Confidence Interval: 0.75–0.80).Conclusion. This novel ESS identified and classified BSIs with a high degree of accuracy. This system requires additional linkages with other related databases.

The recent introduction of the seven-valent pneumococcal conjugate vaccine has led to changes in the proportion of disease caused by different serotypes. The serotypes targeted by the vaccine have been reduced, and Streptococcus pneumonia serotype 19A is now the most commonly isolated serotype causing invasive pneumococcal disease. This serotype has been associated with antibiotic resistance. The authors of this article conducted a review of cases of invasive pneumococcal disease diagnosed between 2000 and 2010 in Calgary, Alberta, to examine the disease course of serotype 19A invasive pneumococcal disease compared with other serotypes.Streptoccocus pneumoniae serotype 19A (ST19A) became an important cause of invasive pneumococcal disease (IPD) after the introduction of the conjugate vaccine.To examine the severity and outcome of ST19A IPD compared with non-ST19A IPD.The Calgary Area Streptococcus pneumoniae Epidemiology Research (CASPER) study collects clinical and laboratory data on all IPD cases in Calgary, Alberta. Analysis was performed on data from 2000 to 2010 comparing ST19A and non-ST19A IPD cases. Adjusted linear and logistic regression models were used to examine outcomes of duration of appropriate intravenous antibiotic therapy and intensive care unit admission, respectively.ST19A tended to cause disease in younger patients. ST19A isolates were more often multidrug resistant (19% versus 0.3%; P0.001). Adjusted logistic regression showed no difference in intensive care unit admission between ST19A and non-ST19A IPD cases (OR 1.4 [95% CI 0.8 to 2.7]). An adjusted linear regression model showed patients18 years of age with a diagnosis of bacteremia and no risk factors infected with ST19A were, on average, treated with antibiotics 1.4 times (95% CI 1.1 to 1.9) as long as patients with non-19A IPD and the same baseline characteristics.ST19A IPD was associated with an increase in average time on antibiotics. Although many of the infecting strains of ST19A were within the threshold for susceptibility, they may be sufficiently resilient to require a longer duration of antibiotic therapy or higher dose to clear the infection.ST19A is more common in younger individuals, is more antibiotic resistant and may require longer average treatment duration.LeExaminer la gravité et les issues de la PI ST19A par rapport aux PI non ST19A.L’étude CASPER de recherche épidémiologique sur leLe ST19A avait tendance à susciter la maladie chez des patients plus jeunes. Les isolats de ST19A étaient plus souvent multi-résistants (19 % par rapport à 0,3 %; P0,001). La régression logistique ajustée ne démontrait aucune différence dans les hospitalisations aux soins intensifs des cas de PI ST19A et des cas de PI non ST19A (RC 1,4 [95 % IC 0,8 à 2,7]). Un modèle de régression linéaire ajusté a révélé que les patients de moins de 18 ans chez qui on avait diagnostiqué une bactériémie, mais qui n’avaient pas de facteurs de risque et qui étaient infectés par le ST19A, étaient traités en moyenne 1,4 fois plus longtemps (95 % IC 1,1 à 1,9) que ceux qui étaient atteints d’une PI non ST19A et qui présentaient les mêmes caractéristiques de départ.La PI ST19A s’associait à une période moyenne d’antibiothérapie plus longue. Même si bon nombre de souches infectieuses du ST19A se situaient dans le seuil de susceptibilité, elles sont peut-être assez résilientes pour qu’une antibiothérapie plus longue ou à plus forte dose puisse éliminer l’infection.Le ST19A est plus courant chez les plus jeunes, résiste davantage aux antibiotiques et a peut-être besoin d’être traité pendant une période moyenne plus longue.

The seven-valent pneumococcal conjugate vaccine (PCV7) was licensed in Canada in 2001. Routine infant vaccination programs in Alberta began in 2002. Several years after PCV7 introduction, the routine use of PCV7 in infants and high-risk children has led to near elimination of invasive pneumococcal disease (IPD) caused by vaccine serotypes.Prospective, population-based surveillance of all IPD cases was conducted from January 1998 to December 2010. Demographic, clinical and microbiologic data were collected.There were 1462 IPD cases over 13 years. Comparing PCV7 serotype IPD incidence in the prevaccine period (1998-2001) to the late postvaccine period (2007-2010), there were declines in children 0-5 months (100%), 6-23 months (98%), 2-4 years (97%), 5-15 years (100%) as well as in adults 16-64 years (73%), 65-84 years (90%) and ≥85 years of age (100%). From 2008 to 2010, there were no cases of PCV7 serotype IPD in children under 2 years of age. There have been increases in non-PCV7 serotype IPD; notably, serotypes 5 and 19A have increased significantly in adults and 19A in children.PCV7 serotype IPD has been eliminated in vaccine-eligible young children and nearly eliminated in all other age groups. Serotype 19A increased significantly at all ages before the introduction of an expanded valency pneumococcal conjugate vaccine.

Background Bloodstream infections (BSI) have been traditionally classified as either community acquired (CA) or hospital acquired (HA) in origin. However, a third category of healthcare-associated (HCA) community onset disease has been increasingly recognized. The objective of this study was to compare and contrast characteristics of HCA-BSI with CA-BSI and HA-BSI. Methods All first episodes of BSI occurring among adults admitted to hospitals in a large health region in Canada during 2000-2007 were identified from regional databases. Cases were classified using a series of validated algorithms into one of HA-BSI, HCA-BSI, or CA-BSI and compared on a number of epidemiologic, microbiologic, and outcome characteristics. Results A total of 7,712 patients were included; 2,132 (28%) had HA-BSI, 2,492 (32%) HCA-BSI, and 3,088 (40%) had CA-BSI. Patients with CA-BSI were significantly younger and less likely to have co-morbid medical illnesses than patients with HCA-BSI or HA-BSI (p < 0.001). The proportion of cases in males was higher for HA-BSI (60%; p < 0.001 vs. others) as compared to HCA-BSI or CA-BSI (52% and 54%; p = 0.13). The proportion of cases that had a poly-microbial etiology was significantly lower for CA-BSI (5.5%; p < 0.001) compared to both HA and HCA (8.6 vs. 8.3%). The median length of stay following BSI diagnosis 15 days for HA, 9 days for HCA, and 8 days for CA (p < 0.001). Overall the most common species causing bloodstream infection were Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. The distribution and relative rank of importance of these species varied according to classification of acquisition. Twenty eight day all cause case-fatality rates were 26%, 19%, and 10% for HA-BSI, HCA-BSI, and CA-BSI, respectively (p < 0.001). Conclusion Healthcare-associated community onset infections are distinctly different from CA and HA infections based on a number of epidemiologic, microbiologic, and outcome characteristics. This study adds further support for the classification of community onset BSI into separate CA and HCA categories.

Background.Electronic surveillance systems (ESSs) that utilize existing information in databases are more efficient than conventional infection surveillance methods.Objective.To develop an ESS for monitoring bloodstream infections (BSIs) and assess whether data obtained from the ESS were in agreement with data obtained by traditional manual medical-record review.Methods.An ESS was developed by linking data from regional laboratory and hospital administrative databases. Definitions for excluding BSI episodes representing contamination and duplicate episodes were developed and applied. Infections were classified as nosocomial infections, healthcare-associated community-onset infections, or community-acquired infections. For a random sample of episodes, data in the ESS were compared with data obtained by independent medical chart review.Results.From the records of the 306 patients whose infections were selected for comparative review, the ESS identified 323 episodes of BSI, of which 107 (33%) were classified as healthcare-associated community-onset infections, 108 (33%) were classified as community-acquired infections, 107 (33%) were classified as nosocomial infections, and 1 (0.3%) could not be classified. In comparison, 310 episodes were identified by use of medical chart review, of which 116 (37%) were classified as healthcare-associated community-onset infections, 95 (31%) as community-acquired infections, and 99 (32%) as nosocomial infections. For 302 episodes of BSI, there was concordance between the findings of the ESS and those of traditional manual chart review. Of the additional 21 discordant episodes that were identified by use of the ESS, 17 (81%) were classified as representing isolation of skin contaminants, by use of chart review. Of the additional 8 discordant episodes further identified by use of chart review, most were classified as repeat or polymicrobial episodes of disease. There was an overall 85% agreement between the findings of the ESS and those of chart review (K = 0.78; standard error, K = 0.04) for classification according to location of acquisition.Conclusion.Our novel ESS allows episodes of BSI to be identified and classified with a high degree of accuracy. This system requires validation in other cohorts and settings.

Summary Objectives To define the incidence, risk factors for acquisition, and outcomes associated with clostridial bacteremia in a large Canadian health region. Methods Retrospective population-based surveillance for clostridial bacteremia was conducted among all residents of the Calgary Health Region (population 1.2 million) during 2000–2006. Results One hundred and thirty-eight residents had incident Clostridium species bacteremia (1.8 per 100,000/year); 45 (33%) were nosocomial, 55 (40%) were healthcare-associated community onset, and 38 (28%) were community acquired. Older age and a number of underlying conditions were risk factors for acquiring Clostridium species bacteremia most importantly hemodialysis [relative risk (RR) 212.3; 95% confidence interval (CI) 106.5–385.5], malignancy (RR 40.2; 95% CI 27.6–58.1), and Crohn's disease (RR 11.2; 95% CI 3.0–29.4). Clostridium perfringens was most commonly identified with 58 (42%) isolates followed by Clostridium septicum (19; 14%), Clostridium ramosum (13; 9%), Clostridium clostridiiforme (8; 6%), and Clostridium difficile (7; 5%). Reduced susceptibility to penicillin occurred in 14/135 (10%), to metronidazole in 2/135 (1%), and to clindamycin in 36/135 (27%) isolates. The median length of stay was 12.7 days and 39/130 (30%) patients died in hospital for mortality rate of 0.5 per 100,000/year. Conclusions Clostridium species bacteremia is associated with a significant burden of illness and hemodialysis and cancer patients are at highest risk.