Andrew E Simor

Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

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Publications (380)1426.05 Total impact

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    ABSTRACT: BACKGROUND Bloodstream infection (BSI) due to methicillin-resistant Staphylococcus aureus (MRSA) is associated with considerable morbidity and mortality. OBJECTIVE To determine the incidence of MRSA BSI in Canadian hospitals and to identify variables associated with increased mortality. METHODS Prospective surveillance for MRSA BSI conducted in 53 Canadian hospitals from January 1, 2008, through December 31, 2012. Thirty-day all-cause mortality was determined, and logistic regression analysis was used to identify variables associated with mortality. RESULTS A total of 1,753 patients with MRSA BSI were identified (incidence, 0.45 per 1,000 admissions). The most common sites presumed to be the source of infection were skin/soft tissue (26.6%) and an intravascular catheter (22.0%). The most common spa types causing MRSA BSI were t002 (USA100/800; 55%) and t008 (USA300; 29%). Thirty-day all-cause mortality was 23.8%. Mortality was associated with increasing age (odds ratio, 1.03 per year [95% CI, 1.02-1.04]), the presence of pleuropulmonary infection (2.3 [1.4-3.7]), transfer to an intensive care unit (3.2 [2.1-5.0]), and failure to receive appropriate antimicrobial therapy within 24 hours of MRSA identification (3.2 [2.1-5.0]); a skin/soft-tissue source of BSI was associated with decreased mortality (0.5 [0.3-0.9]). MRSA genotype and reduced susceptibility to vancomycin were not associated with risk of death. CONCLUSIONS This study provides additional insight into the relative impact of various host and microbial factors associated with mortality in patients with MRSA BSI. The results emphasize the importance of ensuring timely receipt of appropriate antimicrobial agents to reduce the risk of an adverse outcome. Infect. Control Hosp. Epidemiol. 2016;1-8.
    Full-text · Article · Jan 2016 · Infection Control and Hospital Epidemiology
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    ABSTRACT: Background: Antimicrobial stewardship may be important in long-term care facilities because of unnecessary or inappropriate antibiotic use observed in these residents, coupled with their increased vulnerability to health care-associated infections. Objectives: To assess antibiotic use in a long-term care facility in order to identify potential antimicrobial stewardship needs. Methods: A retrospective descriptive study was conducted at the Veterans Centre, a long-term care facility at Sunnybrook Health Sciences Centre, Toronto, Ontario. All residents taking one or more antibiotics (n = 326) were included as participants. Antibiotic-use data for patients residing in the facility between April 1, 2011, and March 31, 2012, were collected and analyzed. Results: Totals of 358 patient encounters, 835 antibiotic prescriptions, and 193 positive culture results were documented during the study period. For 36% (302/835) of antibiotic prescriptions, the duration was more than 7 days. Cephalosporins (30%; 251/835) and fluoroquinolones (28%; 235/835) were the most frequently prescribed antibiotic classes. Urine was the most common source of samples for culture (60%; 116/193). Conclusions: Characteristics of antimicrobial use at this long-term care facility that might benefit from further evaluation included potentially excessive use of fluoroquinolones and cephalosporins and potentially excessive duration of antibiotic use for individual patients.
    No preview · Article · Dec 2015
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    ABSTRACT: Rationale: The impact of hospital length of stay (LOS) on the distribution and susceptibility of Gram negative bacteria (GNB) causing infection in burn patients remains unexplored. Knowledge of causative pathogens is important in guiding empiric antibiotic therapy. Objectives: To characterize the distribution of GNB causing infection and to identify changes in susceptibility with LOS in a tertiary care burn center. Methods: A retrospective review of all admissions to the Ross Tilley Burn Centre at Sunnybrook Health Sciences Centre with clinical cultures yielding GNB (duplicates excluded) between March 12, 2010 to July 17, 2013 was completed. Positive cultures were categorized into 5 clinically relevant time periods (in days) based on specimen collection date relative to the patient's date of admission: 0-7, 7-14, 14-21, 21-28, >28. Chi-square for proportions was used to compare the time periods. Results: The proportion of patients with clinical cultures for P. aeruginosa increased with hospital LOS (0-7 days: 8% vs. >28 days: 55%; p<0.05). Conversely, clinical cultures for H. influenzae occurred primarily within the first 7 days of hospitalization (0-7 days: 36% vs. >28 days: 0.7%; p<0.05). Enterobacteriaceae isolation was highest between 7 and 14 days of hospitalization (7-14 days: 62% vs. >28 days: 38%; p<0.05). Antibiotic resistance was directly proportional to hospital LOS (% patients with multidrug resistant GNB increased from 6% [LOS 0-7days] to 44% [LOS>28 days]; p<0.05). Conclusions: This study provides objective data documenting changes in species and resistance patterns of GNB causing infection in patients admitted to a burn center as a function of hospital LOS; which may support delaying the use of broad spectrum antibiotics (e.g. carbapenems and beta-lactam/beta-lactamase inhibitors) in clinically stable patients.
    No preview · Article · Nov 2015 · Burns: journal of the International Society for Burn Injuries
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    ABSTRACT: Background: Pseudomonas aeruginosa, one of the leading causes of nosocomial gram-negative bloodstream infections, is particularly difficult to treat because of its multiple resistance mechanisms combined with a lack of novel antipseudomonal antibiotics. Despite knowledge of time-dependent killing with ß-lactam antibiotics, most hospitals in Canada currently administer ß-lactam antibiotics by intermittent rather than extended infusions. Objectives: To determine clinical outcomes, microbiological outcomes, total hospital costs, and infection-related costs for patients with P. aeruginosa bacteremia who received intermittent IV administration of antipseudomonal ß-lactam antibiotics in a tertiary care institution. Methods: For this retrospective descriptive study, data were collected for patients who were admitted between March 1, 2005, and March 31, 2013, who had P. aeruginosa bacteremia during their admission, and who received at least 72 h of treatment with ceftazidime, meropenem, or piperacillin-tazobactam. Clinical and microbiological outcomes were determined, and total and infection-related hospital costs were calculated. Results: A total of 103 patients were included in the analysis, of whom 79 (77%) experienced clinical cure. In addition, bacterial eradication was achieved in 41 (87%) of the 47 patients with evaluable data for this outcome. Twenty-eight (27%) of the 103 patients died within 30 days of discontinuation of antipseudomonal ß-lactam antibiotic therapy. The median total cost of the hospital stay was $121 718, and the median infection-related cost was $29 697. Conclusions: P. aeruginosa bacteremia is a clinically significant nosocomial infection that continues to cause considerable mortality and health care costs. To the authors' knowledge, no previous studies have calculated total and infection-related hospital costs for treatment of P. aeruginosa bacteremia with intermittent infusion of antipseudomonal ß-lactam antibiotics, with characterization of cost according to site of acquisition of the infection. This study may provide important baseline data for assessing the impact of implementing extended-infusion ß-lactam therapy, antimicrobial stewardship, and infection control strategies targeting P. aeruginosa infection in hospitalized patients.
    No preview · Article · Oct 2015
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    ABSTRACT: Background: Extended-spectrum β-lactamase (ESBL)-producing bacteria are important sources of infection; however, Canadian data evaluating the impact of ESBL-associated infection are lacking. Aim: To determine whether patients infected with ESBL-producing Escherichia coli or Klebsiella species (ESBL-EcKs) exhibit differences in clinical outcome, microbiological outcome, mortality, and/or hospital resource use compared to patients infected with non-ESBL-producing strains. Methods: A retrospective case-control study of 75 case patients with ESBL-EcKs matched to controls infected with non-ESBL-EcKs who were hospitalized from June 2010 to April 2013 was conducted. Patient-level cost data were provided by the institution's business office. Clinical data were collected using the electronic databases and paper charts. Findings: Median infection-related hospitalization costs per patient were greater for cases than controls (C$10,507 vs C$7,882; median difference: C$3,416; P = 0.04). The primary driver of increased costs was prolonged infection-related hospital length of stay (8 vs 6 days; P = 0.02) with patient location (ward, ICU) and indirect care costs (including costs associated with infection prevention and control) as the leading cost categories. Cases were more likely to experience clinical failure (25% vs 11%; P = 0.03), with a higher all-cause mortality (17% vs 5%; P = 0.04). Less than half of case patients were prescribed appropriate empiric antimicrobial therapy, whereas controls received adequate initial treatment in nearly all circumstances (48% vs 96%; P < 0.01). Conclusion: Patients with infection caused by ESBL-EcKs are at increased risk for clinical failure and mortality, with additional cost to the Canadian healthcare system of C$3,416 per patient.
    No preview · Article · Oct 2015 · The Journal of hospital infection

  • No preview · Article · Sep 2015 · Diagnostic microbiology and infectious disease
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    ABSTRACT: Background: Clostridium difficile infection (CDI) is the most common cause of nosocomial infectious diarrhea and may result in severe complications including death. We conducted a prospective study to identify risk factors for complications of CDI (cCDI). Methods: Adult inpatients with confirmed CDI in 10 Canadian hospitals were enrolled and followed for 90 days. Potential risk factors were measured within 24 hours of diagnosis. Isolates were typed by PCR-ribotyping. cCDI was defined as one or more of: colonic perforation, toxic megacolon, colectomy, admission to an intensive care unit for cCDI, or if CDI contributed to death within 30 days of enrollment. Risk factors for cCDI were investigated by logistic regression. Results: A total of 1380 patients were enrolled. cCDI was observed in 8% of patients. The ribotype was identified in 922 patients of whom 52% were infected with R027. Age≥80 years, heart rate >90/minute, respiratory rate>20/minute, white cell count <4x10(9)/L or ≥20x10(9)/L, albumin <25 g/L, BUN >7mmol/L, and CRP≥150 mg/L were independently associated with cCDI. A higher frequency of cCDI was observed among R027-infected patients (10.9% vs.7.2%) but the association was not significant in adjusted analysis. Conclusion: CDI complications were associated with older age, abnormal blood tests and abnormal vital signs. These factors, readily available to clinicians at the time of diagnosis, could be used for outcome prediction and risk stratification to select patients who may need closer monitoring or more aggressive therapy.
    No preview · Article · Sep 2015 · Clinical Infectious Diseases
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    ABSTRACT: We analyzed the matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) of smudge plate growth for bacterial identification from 400 blood cultures. Ninety-seven percent of Gram-negative bacilli and 85% of Gram-positive organisms were correctly identified within 4 h; only eight isolates (2.0%) were misidentified. This method provided rapid and accurate microbial identification from positive blood cultures.
    No preview · Article · Jul 2015 · Journal of clinical microbiology
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    ABSTRACT: The task-oriented nurse acuity system (TONAS) has long been used to calculate nursing care needs on hospital patient units, and include nursing documentation on indwelling urinary catheter use. We performed a 2500-patient validation study of our organization's TONAS, which demonstrated high interrater reliability with manual audits (κ >0.92). For institutions that continue to rely on manual surveillance of urinary catheter use, a TONAS may represent a reliable method of automated surveillance. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Jul 2015 · American journal of infection control
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    ABSTRACT: Only a portion of hospital-acquired Clostridium difficile infections can be traced back to source patients identified as having symptomatic disease. Antibiotic exposure is the main risk factor for C difficile infection for individual patients and is also associated with increased asymptomatic shedding. Contact with patients taking antibiotics within the same hospital ward may be a transmission risk factor for C difficile infection, but this hypothesis has never been tested. To obtain a complete portrait of inpatient risk that incorporates innate patient risk factors and transmission risk factors measured at the hospital ward level and to investigate ward-level rates of antibiotic use and C difficile infection risk. A 46-month (June 1, 2010, through March 31, 2014) retrospective cohort study of inpatients 18 years or older in a large, acute care teaching hospital composed of 16 wards, including 5 intensive care units and 11 non-intensive care unit wards. Patient-level risk factors (eg, age, comorbidities, hospitalization history, antibiotic exposure) and ward-level risk factors (eg, antibiotic therapy per 100 patient-days, hand hygiene adherence, mean patient age) were identified from hospital databases. Incidence of hospital-acquired C difficile infection as identified prospectively by hospital infection prevention and control staff. A total of 255 of 34 298 patients developed C difficile (incidence rate, 5.95 per 10 000 patient-days; 95% CI, 5.26-6.73). Ward-level antibiotic exposure varied from 21.7 to 56.4 days of therapy per 100 patient-days. Each 10% increase in ward-level antibiotic exposure was associated with a 2.1 per 10 000 (P < .001) increase in C difficile incidence. The association between C difficile incidence and ward antibiotic exposure was the same among patients with and without recent antibiotic exposure, and C difficile risk persisted after multilevel, multivariate adjustment for differences in patient-risk factors among wards (relative risk, 1.34 per 10% increase in days of therapy; 95% CI, 1.16-1.57). Among hospital inpatients, ward-level antibiotic prescribing is associated with a statistically significant and clinically relevant increase in C difficile risk that persists after adjustment for differences in patient-level antibiotic use and other patient- and ward-level risk factors. These data strongly support the use of antibiotic stewardship as a means of preventing C difficile infection.
    Full-text · Article · Feb 2015 · JAMA Internal Medicine
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    ABSTRACT: A national point-prevalence survey for infection or colonization with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE), and for Clostridium difficile infection (CDI) was done in Canadian hospitals in 2010. A follow-up survey was done in Nov. 2012 to determine whether there were any changes in the prevalence of these organisms; we also determined the prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, and carbapenem-resistant Enterobacteriaceae (CREs). Associations between prevalence and infection prevention and control policies were evaluated in logistic regression models. 143 (67% of eligible facilities) hospitals with 29,042 adult inpatients participated in the survey, with representation from all 10 provinces; 132 hospitals participated in 2010 and 2012. There were no significant changes in the median prevalence of MRSA in 2010 (4.3%) as compared to 2012 (3.9%), or of CDI in 2010 (0.8%) as compared to 2012 (0.9%). A higher median prevalence of VRE was identified in 2012 (1.3%) as compared to 2010 (0.5%) (p=0.04), despite decreased VRE screening in 2012. The median prevalence of ESBLs was 0.7% and was 0 for CREs; CREs were reported from only 10 (7.0%) hospitals. A policy of routinely caring for patients with MRSA or VRE in a private isolation room was associated with lower prevalence of these organisms. Targeted screening of high risk patients on admission was associated with lower MRSA prevalence; higher hand hygiene compliance was associated with lower VRE prevalence. These data provide national prevalence rates for antibiotic resistant organisms among adults hospitalized in Canadian hospitals. Certain infection prevention and control policies were associated with prevalence. Copyright © 2015. Published by Elsevier Ltd.
    No preview · Article · Feb 2015 · Clinical Microbiology and Infection
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    ABSTRACT: The usefulness of carbapenems for gram-negative infections is becoming compromised by organisms harboring carbapenemases, enzymes which can hydrolyze the drug. Currently KPC (class A), NDM (class B), and OXA-48 types (class D) are the most globally widespread carbapenemases. However, among the GES-type class A extended-spectrum β-lactamases (ESBLs) there are variants that hydrolyze carbapenems, with blaGES-5 being the most common. Two Escherichia coli and two Serratia marcescens harboring blaGES-5 on plasmids were isolated by the Canadian Nosocomial Infection Surveillance Program (CNISP) from four different patients in a single hospital over a 2-year period. Complete sequencing of the blaGES-5 plasmids indicated that all four had nearly identical backbones consisting of genes for replication, partitioning, and stability, but contained variant accessory regions consisting of mobile elements and antimicrobial resistance genes. The plasmids were of a novel replicon type, but belonged to the MOBQ1 group based on relaxase sequences, and appeared to be mobilizable, but not self-transmissible. Considering the time periods of bacterial isolation, it would appear the blaGES-5 plasmid has persisted in an environmental niche for at least 2 years in the hospital. This has implications for infection control and clinical care when it is transferred to clinically relevant gram-negative organisms.
    No preview · Article · Dec 2014 · Microbial drug resistance (Larchmont, N.Y.)
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    ABSTRACT: Background: Influenza poses a particular threat to vulnerable hospitalized patients. We reviewed the characteristics of hospital acquired influenza identified by surveillance in Toronto from 2005 to 2012. Methods: The Toronto Invasive Bacterial Diseases Network has performed population based surveillance for laboratory confirmed influenza associated with hospitalization in south central Ontario since the 2004/5 influenza season. Eligible patients were those with influenza identified by EIA, DFA, culture, and/or RT-PCR who either required hospitalization for the illness associated with the positive test, or were admitted to an acute care hospital when the specimen was obtained. Acute care hospital acquired influenza (HAI) was defined as influenza with symptom onset >72 hours after hospital admission. Results: Between January 2005 and May 2012, 3130 adult influenza cases were identified, of which 318 (10%) were HAI. Of these, 268 were Influenza A (54 H1N1, 112 H3N2, and 103 not subtyped) and 50 were Influenza B. The median rate of HAI was 1.15 per 100,000 patient days (range 0.47-1.93) with no discernible trend. 22% of cases were associated with declared hospital outbreaks. Compared to community acquired cases, patients with HAI were older (70 vs 66 years old, p<0.01), more likely to have prior chronic illness (95.3% vs 90.6%, p<0.01), and more likely to be infected by influenza A (84% vs 77%, p<0.05). At diagnosis, only 40% of hospital acquired cases met the CDC definition for Influenza-like illness. Patients with hospital acquired influenza were more likely to require ICU admission (26% vs 20%, p<0.001) and more likely to die within 15 days of diagnosis (18% vs 9%, p<0.001). Median time from admission to onset of symptoms was 12 days (range 3-209 days). 192/318 (60%) patients were treated with antibiotics, and 217/318 (68%) with antivirals (compared to 84% and 59% in community acquired cases, respectively). Median time from symptom onset to antiviral therapy was 48 hours. Conclusion: Hospital acquired influenza has atypical presentations and results in a significant number of ICU admissions and deaths. Our surveillance identified only a fraction of cases. Active surveillance studies are needed to further define clinical criteria for influenza testing, and to identify cases occurring after hospital discharge.
    No preview · Conference Paper · Oct 2014
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    ABSTRACT: Background: Measurement of the prevalence of antibiotic resistance assesses the associated burden of disease while also identifying vulnerable patient populations and monitoring the effectiveness of interventions. The objective of this study was to determine institutional characteristics, and infection prevention and control (IP&C) policies associated with MRSA colonization/infection, and C. difficile infection. Methods: In November 2012 a point-prevalence survey of MRSA and CDI was done in adult inpatients at Canadian acute-care hospitals with ≥50 beds. Information was also obtained regarding institutional characteristics and IP&C policies of each participating facility. Logistic regression models were designed using variables selected a priori and two-tailed p values less than 0.05 were considered significant. Results: 132 (56% of eligible) hospitals representing all 10 Canadian provinces participated in the survey and were included in the analysis. 60% of facilities were located within the central region of Canada (Ontario and Quebec), the majority (54%) had fewer than 200 beds, and were non-teaching hospitals (68%). The median prevalence of MRSA colonization/infection was 3.9% (range: 0-26.8%) and median MRSA infection prevalence was 0.3% (range: 0-4.9%). The presence of pediatrics in the hospital (p=0.001), performing targeted versus universal admission screening (p<0.001), routine placement of MRSA carriers in a private room (p<0.001), routine use of surgical masks by staff caring for patients with MRSA (p=0.005), decolonization with mupirocin (p<0.001), and enhanced environmental cleaning of MRSA rooms (p=0.006) were independently associated with a lower prevalence of MRSA colonization/infection. The median prevalence of CDI for participating facilities was 0.9% (0-5.5%). Teaching hospitals (p=0.011) and facilities with a shorter turn-around-time (< 24 hrs) for C. difficile toxin assay results (p=0.012) were associated with a higher prevalence of CDI. Conclusion: Although hospital characteristics are inalterable, this study identified IP&C policies that may be used to limit the spread of antibiotic resistance in acute-care hospitals.
    No preview · Conference Paper · Oct 2014
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    ABSTRACT: Background: Community-associated methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a leading cause of purulent skin and soft tissue infections (SSTI) in many areas of the world. The evolving epidemiology of MRSA in SSTIs across Canada is seldom described. This study characterizes the changing prevalence and microbiology of MRSA in patients presenting to emergency departments (EDs) across Canada over half a decade. Methods: Using a prospective, observational design, we enrolled patients presenting to 27 hospital EDs (spanning 7 provinces) with acute purulent SSTIs over 3 phases: P1 - 7/1/2008 to 4/30/2009; P2 - 1/16/2012 to 11/30/2012; and P3 - 4/28/2013 to 3/31/2014. Participating EDs agreed to collect wound swabs on all patients presenting with purulent SSTIs. Eligible patients were those whose wound cultures grew S. aureus. Antimicrobial susceptibility testing by broth microdilution in accordance with CLSI guidelines was undertaken on all isolates. Structured chart audits were undertaken. Simple proportions are reported at site, regional and provincial levels and compared using Chi-squared/Fisher exact test, as appropriate. Results: A total of 4752 (P1: 1340; P2: 1622; P3: 1790) S. aureus positive encounters were recorded over the 3 phases. Accounting for all sites, the overall MRSA prevalence decreased significantly between P1 (31%) and P2 (27%, p=0.002), and remained unchanged in P3 (28%, p=0.42). A similar trend was observed among the 12 sites that participated in all 3 phases (P1 vs. P2: p=0.004; P2 vs. P3: p=0.70). Among the 18 sites participating in at least two study phases, most (61%) experienced a declining trend in MRSA prevalence, while 28% of them observed an increase (3 Ontario and 2 Alberta sites). City-level analyses revealed variability in the MRSA prevalence. Most cities experienced a decrease in the prevalence. Overall, the highest prevalence was seen in the western provinces of British Columbia (P1: 44%, P2: 66%, P3: 53%), Saskatchewan (P2: 47%, P3: 48%), and Alberta (P1: 48%, P2: 28%, P3: 31%) during all phases, while the lowest prevalence was observed in Quebec (P1: 20%, P2: 19%, P3: 11%). Conclusion: MRSA epidemiology continues to evolve across Canada. While the overall Canadian prevalence of MRSA in SSTIs remains substantial, it is variable across the country, and appears to be decreasing regionally.
    Full-text · Conference Paper · Oct 2014
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    ABSTRACT: Objectives Inappropriate antimicrobial use can promote antimicrobial resistance, which is associated with increased patient morbidity and mortality. Identifying the pattern of antimicrobial use can provide data from which targeted antimicrobial stewardship interventions can be made. The primary objective was to identify the prevalence of antimicrobial use at a tertiary care teaching hospital with both acute and long-term care patients. Methods A point prevalence study was conducted on July 19th, 2012. Data on antimicrobial utilization, indication for prescribing, duration of therapy, and frequency of infectious disease or antimicrobial stewardship consultations were collected using a customized integrated stewardship database (SPIRIT) and prospective chart review. Results One or more antimicrobial agents were ordered in 31% and 4% of acute care and long-term care patients, respectively. Respiratory and urinary tract infections were the most common indication for antimicrobial therapy in both acute and long-term care. About 25% of surgical prophylaxis orders were prescribed for greater than 24 h. Conclusion This prospective point prevalence survey provided important baseline information on antimicrobial use within a large tertiary care teaching hospital and identified potential targets for future antimicrobial stewardship initiatives. A multi-center point prevalence survey should be considered to identify patterns of antimicrobial use in Canada and to establish the first steps toward international antimicrobial surveillance.
    No preview · Article · Aug 2014 · Journal of Epidemiology and Global Health
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    ABSTRACT: Introduction We compared the economic impacts of linezolid and vancomycin for the treatment of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA)–confirmed nosocomial pneumonia. Methods We used a 4-week decision tree model incorporating published data and expert opinion on clinical parameters, resource use and costs (in 2012 US dollars), such as efficacy, mortality, serious adverse events, treatment duration and length of hospital stay. The results presented are from a US payer perspective. The base case first-line treatment duration for patients with MRSA-confirmed nosocomial pneumonia was 10 days. Clinical treatment success (used for the cost-effectiveness ratio) and failure due to lack of efficacy, serious adverse events or mortality were possible clinical outcomes that could impact costs. Cost of treatment and incremental cost-effectiveness per successfully treated patient were calculated for linezolid versus vancomycin. Univariate (one-way) and probabilistic sensitivity analyses were conducted. Results The model allowed us to calculate the total base case inpatient costs as $46,168 (linezolid) and $46,992 (vancomycin). The incremental cost-effectiveness ratio favored linezolid (versus vancomycin), with lower costs ($824 less) and greater efficacy (+2.7% absolute difference in the proportion of patients successfully treated for MRSA nosocomial pneumonia). Approximately 80% of the total treatment costs were attributed to hospital stay (primarily in the intensive care unit). The results of our probabilistic sensitivity analysis indicated that linezolid is the cost-effective alternative under varying willingness to pay thresholds. Conclusion These model results show that linezolid has a favorable incremental cost-effectiveness ratio compared to vancomycin for MRSA-confirmed nosocomial pneumonia, largely attributable to the higher clinical trial response rate of patients treated with linezolid. The higher drug acquisition cost of linezolid was offset by lower treatment failure–related costs and fewer days of hospitalization.
    Full-text · Article · Jul 2014 · Critical care (London, England)
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    ABSTRACT: Elevators are ubiquitous and active inside hospitals, potentially facilitating bacterial transmission. The objective of this study was to estimate the prevalence of bacterial colonization on elevator buttons in large urban teaching hospitals. A total of 120 elevator buttons and 96 toilet surfaces were swabbed over separate intervals at 3 tertiary care hospitals on weekdays and weekends in Toronto, Ontario. For the elevators, swabs were taken from 2 interior buttons (buttons for the ground floor and one randomly selected upper-level floor) and 2 exterior buttons (the "up" button from the ground floor and the "down" button from the upper-level floor). For the toilet surfaces, swabs were taken from the exterior and interior handles of the entry door, the privacy latch, and the toilet flusher. Samples were obtained using standard bacterial collection techniques, followed by plating, culture, and species identification by a technician blind to sample source. The prevalence of colonization of elevator buttons was 61% (95% confidence interval 52%-70%). No significant differences in colonization prevalence were apparent in relation to location of the buttons, day of the week, or panel position within the elevator. Coagulase-negative staphylococci were the most common organisms cultured, whereas Enterococcus and Pseudomonas species were infrequent. Elevator buttons had a higher prevalence of colonization than toilet surfaces (61% v. 43%, p = 0.008). Hospital elevator buttons were commonly colonized by bacteria, although most pathogens were not clinically relevant. The risk of pathogen transmission might be reduced by simple countermeasures.
    Preview · Article · Jul 2014 · Open Medicine
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    ABSTRACT: BACKGROUND: Estimating the risk of antibiotic resistance is important in selecting empiric antibiotics. We asked how the timing, number of courses, and duration of antibiotic therapy in the previous 3 months affected antibiotic resistance in isolates causing invasive pneumococcal disease (IPD). METHODS: We conducted prospective surveillance for IPD in Toronto, Canada, from 2002 to 2011. Antimicrobial susceptibility was measured by broth microdilution. Clinical information, including prior antibiotic use, was collected by chart review and interview with patients and prescribers. RESULTS: Clinical information and antimicrobial susceptibility were available for 4062 (90%) episodes; 1193 (29%) of episodes were associated with receipt of 1782 antibiotic courses in the prior 3 months. Selection for antibiotic resistance was class specific. Time elapsed since most recent antibiotic was inversely associated with resistance (cephalosporins: adjusted odds ratio [OR] per day, 0.98; 95% confidence interval [CI], .96-1.00; P = .02; macrolides: OR, 0.98; 95% CI, .96-.99; P = .005; penicillins: OR [log(days)], 0.62; 95% CI, .44-.89; P = .009; fluoroquinolones: profile penalized-likelihood OR [log(days)], 0.62; 95% CI, .39-1.04; P = .07). Risk of resistance after exposure declined most rapidly for fluoroquinolones and penicillins and reached baseline in 2-3 months. The decline in resistance was slowest for macrolides, and in particular for azithromycin. There was no significant association between duration of therapy and resistance for any antibiotic class. Too few patients received multiple courses of the same antibiotic class to assess the significance of repeat courses. CONCLUSIONS: Time elapsed since last exposure to a class of antibiotics is the most important factor predicting antimicrobial resistance in pneumococci. The duration of effect is longer for macrolides than other classes.
    Full-text · Article · Jun 2014 · Clinical Infectious Diseases
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    ABSTRACT: Our objective was to rigorously evaluate the impact of an antimicrobial stewardship audit-and-feedback intervention, via a stepped-wedge randomized trial. An effective intensive care unit (ICU) audit-and-feedback program was rolled out to 6 non-ICU services in a randomized sequence. The primary outcome was targeted antimicrobial utilization, using a negative binomial regression model to assess the impact of the intervention while accounting for secular and seasonal trends. The intervention was successfully transitioned, with high volumes of orders reviewed, suggestions made, and recommendations accepted. Among patients meeting stewardship review criteria, the intervention was associated with a large reduction in targeted antimicrobial utilization (−21%, P = .004); however, there was no significant change in targeted antibiotic use among all admitted patients (−1.2%, P = .9), and no reductions in overall costs and microbiologic outcomes. An ICU day 3 audit-and-feedback program can be successfully expanded hospital-wide, but broader benefits on non-ICU wards may require interventions earlier in the course of treatment.
    No preview · Article · Jun 2014 · Clinical Infectious Diseases

Publication Stats

11k Citations
1,426.05 Total Impact Points

Institutions

  • 1994-2015
    • Sunnybrook Health Sciences Centre
      • • Division of Microbiology
      • • Division of Clinical Pharmacology and Toxicology
      Toronto, Ontario, Canada
  • 1983-2015
    • University of Toronto
      • • Sunnybrook Health Sciences Centre
      • • Department of Laboratory Medicine and Pathobiology
      • • Department of Medicine
      • • Division of Infectious Diseases
      • • Faculty of Dentistry
      Toronto, Ontario, Canada
  • 2010
    • University of Guelph
      • Department of Pathobiology
      Guelph, Ontario, Canada
  • 2002-2008
    • National Microbiology Laboratory, Canada
      Winnipeg, Manitoba, Canada
  • 2007
    • Public Health Agency of Canada
      Ottawa, Ontario, Canada
  • 1991-2004
    • Mount Sinai Hospital, Toronto
      • • Department of Microbiology
      • • Department of Dentistry
      Toronto, Ontario, Canada
    • Baycrest
      Toronto, Ontario, Canada
  • 2003
    • Health Canada
      Ottawa, Ontario, Canada
  • 1996-2003
    • SickKids
      • Division of Infectious Diseases
      Toronto, Ontario, Canada
  • 2000-2001
    • Women's College Hospital
      Toronto, Ontario, Canada
  • 1995
    • University of Tennessee
      Knoxville, Tennessee, United States
  • 1993
    • Hôpital St-Boniface Hospital
      Winnipeg, Manitoba, Canada
  • 1990-1993
    • The Princess Margaret Hospital
      Toronto, Ontario, Canada
  • 1992
    • University of Manitoba
      Winnipeg, Manitoba, Canada