A E Simor

University of Toronto, Toronto, Ontario, Canada

Are you A E Simor?

Claim your profile

Publications (349)1296.31 Total impact

  • Source
    [Show abstract] [Hide abstract]
    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.
    JAMA Internal Medicine 02/2015; DOI:10.1001/jamainternmed.2014.8273 · 13.25 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
  • [Show abstract] [Hide abstract]
    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.
    Microbial drug resistance (Larchmont, N.Y.) 12/2014; DOI:10.1089/mdr.2014.0205 · 1.99 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
  • [Show abstract] [Hide abstract]
    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.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
  • [Show abstract] [Hide abstract]
    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.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
  • [Show abstract] [Hide abstract]
    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.
    08/2014; DOI:10.1016/j.jegh.2014.06.003
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The economic impacts of linezolid and vancomycin were compared for the treatment of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA)-confirmed nosocomial pneumonia.
    Critical care (London, England) 07/2014; 18(4):R157. DOI:10.1186/cc13996 · 5.04 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Clinical Infectious Diseases 06/2014; 59(7). DOI:10.1093/cid/ciu497 · 9.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Our objective was to rigorously evaluate the impact of an antimicrobial stewardship audit-and-feedback intervention, via a stepped-wedge randomized controlled trial. An effective 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=0.004); however, there was no significant change in targeted antibiotic use among all admitted patients (-1.2%, p=0.9), 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.
    Clinical Infectious Diseases 06/2014; 59(6). DOI:10.1093/cid/ciu445 · 9.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Rationale: Variability in neonatal vancomycin pharmacokinetics and lack of consensus for optimal trough concentrations in neonatal intensive care units poses challenges to dosing vancomycin in neonates.Objective: To determine vancomycin pharmacokinetics in neonates and evaluate dosing regimens to identify whether practical initial recommendations that targeted trough concentrations most commonly used in neonatal intensive care units could be determined.Methods: Fifty neonates who received vancomycin with at least one set of steady-state levels were evaluated retrospectively. Mean pharmacokinetics were determined using first-order pharmacokinetic equations and Monte Carlo Simulation was used to evaluate initial dosing recommendations for target troughs of 15-20 mg/L, 5-20 mg/L and ≤ 20 mg/L.Results: Monte Carlo Simulation revealed that mg/kg dosing was optimal, where intermittent dosing of 9-12 mg/kg iv q8h had the highest probability of attaining a target trough of 15-20 mg/L. However, continuous infusion with a loading dose of 10mg/kg followed by 25-30 mg/kg/24h had the best overall probability of target attainment. Initial intermittent dosing of 9-15 mg/kg iv q12h was optimal for target troughs of 5-20 mg/L and ≤ 20 mg/L.Conclusions: Practical initial vancomycin dosing of 10mg/kg vancomycin iv q12h or q8h for desired vancomycin troughs of either 5-20mg/L or ≤ 20 mg/L and 15-20mg/L, respectively, were determined. However, due to large interpatient vancomycin pharmacokinetic variability in neonates, monitoring of serum concentrations is recommended when trough concentrations between 15-20mg/L or 5-20mg/L are desired.
    Antimicrobial Agents and Chemotherapy 03/2014; 58(5). DOI:10.1128/AAC.01718-13 · 4.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are associated with considerable morbidity and mortality, especially with persistent (PB) or recurrent bacteremia (RB).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Zimbabwe underwent a socioeconomic crisis and resultant increase in food insecurity in 2008-9. The impact of the crisis on Tuberculosis (TB) incidence is unknown. Prospective databases from two mission hospitals, which were geographically widely separated, and remained open during the crisis, were reviewed. At the Howard Hospital (HH) in northern Zimbabwe, TB incidence increased 35% in 2008 from baseline rates in 2003-2007 (p<0.01) and remained at that level in 2009. Murambinda Hospital (MH) in Eastern Zimbabwe also demonstrated a 29% rise in TB incidence from 2007 to 2008 (p<0.01) and remained at that level in 2009. Data collected post-crisis at HH showed a decrease of 33% in TB incidence between 2009 to 2010 (p<0.001) and 2010/2011 TB incidence remained below that of the crisis years of 2008/2009 (p<0.01). Antenatal clinic HIV seroprevalence at HH decreased between 2001(23%) to 2011(11%) (p<0.001). Seasonality of TB incidence was analyzed at both MH and HH. There was a higher TB incidence in the dry season when food is least available (September-November) compared to post harvest (April-June) (p<0.001). This study suggests that an epidemic of TB mirrored socioeconomic collapse and recovery in Zimbabwe. The seasonal data suggests that food security may have been associated with TB incidence both annually and during the crisis in this high HIV prevalence country.
    PLoS ONE 02/2014; 9(2):e83387. DOI:10.1371/journal.pone.0083387 · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Emergence of plasmids harbouring blaNDM-1 is a major public health concern due to their association with multidrug resistance and their potential mobility. PCR was used to detect blaNDM-1 from clinical isolates of Providencia rettgeri (PR) and Klebsiella pneumoniae (KP). Antimicrobial susceptibilities were determined using Vitek 2. The complete DNA sequence of two blaNDM-1 plasmids (pPrY2001 and pKp11-42) was obtained using a 454-Genome Sequencer FLX. Contig assembly and gap closures were confirmed by PCR-based sequencing. Comparative analysis was done using BLASTn and BLASTp algorithms. Both clinical isolates were resistant to all β-lactams, carbapenems, aminoglycosides, ciprofloxacin and trimethoprim/sulfamethoxazole, and susceptible to tigecycline. Plasmid pPrY2001 (113 295 bp) was isolated from PR. It did not show significant homology to any known plasmid backbone and contained a truncated repA and novel repB. Two blaNDM-1-harbouring plasmids from Acinetobacter lwoffii (JQ001791 and JQ060896) shared 100% similarity to a 15 kb region that contained blaNDM-1. pPrY2001 also contained a type II toxin/antitoxin system. pKp11-42 (146 695 bp) was isolated from KP. It contained multiple repA genes. The plasmid backbone had the highest homology to the IncFIIk plasmid type (51% coverage, 100% nucleotide identity). The blaNDM-1 region was unique in that it was flanked upstream by IS3000 and downstream by a novel transposon designated Tn6229. pKp11-42 also contained a number of mutagenesis and plasmid stability proteins. pPrY2001 differed from all known plasmids due to its novel backbone and repB. pKp11-42 was similar to IncFIIk plasmids and contained a number of genes that aid in plasmid persistence.
    Journal of Antimicrobial Chemotherapy 11/2013; 69(3). DOI:10.1093/jac/dkt445 · 5.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Pulsed-field gel electrophoresis (PFGE) is a valuable molecular typing assay used for methicillin-resistant Staphylococcus aureus (MRSA) surveillance and genotyping. However, there are several limitations associated with PFGE. In Alberta, Canada, the significant increase in the number of MRSA isolates submitted to the Provincial Laboratory for Public Health (ProvLab) for PFGE typing led to the need for an alternative genotyping method. In this study, we describe the transition from PFGE to Staphylococcus protein A (spa), Staphylococcal cassette chromosome (SCCmec), and Panton-Valentine leukocidin (PVL) typing. A total of 1915 clinical MRSA isolates collected from 2005 to 2009 were used to develop and validate an algorithm for assigning PFGE epidemic types using spa, SCCmec, and PVL typing and the resulting data was used to populate a new Alberta MRSA typing database. An additional 12620 clinical MRSA isolates collected from 2010 to 2012 as part of ongoing routine molecular testing at ProvLab were characterized using the new typing algorithm and the Alberta MRSA typing database. Switching to spa, SCCmec, and PVL from PFGE typing substantially reduced hands-on and turn-around times while maintaining historical PFGE epidemic type designations. This led to an approximate $77,000 reduction in costs from 2010 to 2012. PFGE typing is still required for a small subset of MRSA isolates that have spa types that are rare, novel, or associated with more than one PFGE epidemic type.
    PLoS ONE 11/2013; 8(11):e79149. DOI:10.1371/journal.pone.0079149 · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea and often results in severe complications including sepsis, colectomy and death. We conducted a prospective study to identify risk factors for complications or death due to CDI. Methods: Adult inpatients with confirmed CDI in 10 acute care hospitals across Quebec and Ontario, Canada, were enrolled in a prospective cohort between 2005 and 2008. A follow-up was performed on day 30 and 90 after enrollment. CDI was defined by diarrhea and a positive toxin (EIA or direct cytotoxin). Complicated CDI (cCDI) was confirmed if one or more of the following was observed: colonic perforation, toxic megacolon, septic shock, colectomy or death within 30 days. Data on potential factors predictive of cCDI were collected within 48 hours of the diagnosis. Isolates were typed by PCR-ribotyping. A multivariate logistic regression model was used to identify predictors of cCDI. Results: A total of 1380 patients were enrolled (median age: 71 years; IQR= 58-80), among whom 86% were experiencing a first episode of CDI, 11% were long-term care residents and only 5% had community-acquired CDI. A stool specimen was collected in 1153 patients, a ribotype was obtained in 807 (70%) among them and 420 (52%) were ribotype 027. A cCDI was observed in 210 patients (16%), from which 169 (81%) died within 30 days and 20% had septic shock. Risk factors predictive of cCDI in the multivariate model were: age (OR per year = 1.02; 95% CI = 1.002-1.03), tube feeding (OR = 2.7; 95% CI = 1.6- 4.5), white cell count >= 20 x 109C/mL (OR = 3.7; 95%CI = 2.1- 6.2), serum creatinine >=150 mmol/dL (OR = 3.02; 95% CI = 2.0- 4.6) and serum albumin ≤ 35 g/L (OR = 5.8; 95% CI = 2.5- 13.6). Surgery in the two months prior CDI was protective (OR = 0.52; 95% CI = 0.35-0.7). Comorbidities, immunosuppression or ribotype 027 were not significantly associated with cCDI. Conclusion: In a prospective multicenter cohort study we identified age, tube feeding, leukocytosis, increased serum creatinine, and hypoalbuminemia as independent predictors of cCDI. Ribotype 027 was not associated with cCDI and recent surgery appeared protective.
    IDWeek 2013 Meeting of the Infectious Diseases Society of America; 10/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: In 1995, a publicly funded pneumococcal vaccination program for 23-valent polysaccharide vaccine (PPV23) was introduced in Ontario. Conjugate vaccines were authorized in 2001 (PCV7), 2009 (PCV10) and 2010 (PCV13). From 1995-2011, active, population-based surveillance for invasive pneumococcal disease (IPD) was conducted in Metropolitan Toronto and Peel Region, Canada. 6404 IPD cases were included. After PPV23 program implementation in 1995, IPD due to PPV23 strains decreased 49% in older adults prior to PCV7 introduction. Estimated PPV23 efficacy in vaccine eligible adults was 42.2% (95% CI; 28.6-53.2%). IPD incidence due to PCV7 serotypes in children <5 years decreased significantly after PCV7 authorization and before introduction of a publicly funded PCV7 program. Seven years after PCV7 program implementation, the incidence of IPD due to PCV7 serotypes decreased to zero in children and by 88% in adults, however, overall IPD incidence remained unchanged in adults. In 2011, the incidence of IPD was 4.5 per 100,000 in adults aged 15-64 and 19.9 per 100,000 in adults aged over 65 years, with 45 serotypes causing disease. Between 1995 and 2011, the case fatality rate of IPD in adults decreased 2% per year (95% CI, -0.9% to -3.2%). In multivariable analysis, predictors of mortality included older age, chronic conditions, nursing home residence, current smoking, bacteraemia, and illness due to serotypes 3,11A, 19A, and 19F. While vaccination programs resulted in substantial public health benefits, herd immunity benefits of PCV7 were seen at low pediatric vaccination rates, and the case fatality rate of IPD has decreased, IPD will continue to be a cause of considerable morbidity and mortality in adults.
    Vaccine 10/2013; 31(49). DOI:10.1016/j.vaccine.2013.09.049 · 3.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Repeated point-prevalence surveys are useful for identifying changes in the epidemiology of antimicrobial resistance. A point-prevalence survey for MRSA, VRE, and CDI was done in 176 Canadian hospitals in 2010. We wanted to determine if there were any changes in prevalence over time. Methods: A follow-up survey of MRSA, VRE, ESBLs, CREs, and CDI prevalence was done in adult inpatients in Canadian hospitals with > 49 beds in Nov. 2012. Data describing the participating hospitals and the patient cases were obtained at each participating site using standard criteria and case definitions. Results: 143 (58% of eligible) hospitals with 29,042 inpatients participated in the follow-up survey with representation from all 10 provinces. 79 (55%) hospitals had 50-200 beds, 58 (41%) had 201-500 beds, and 6 (4%) had > 500 beds. Most (90%) hospitals did routine screening for MRSA and VRE. 132 hospitals participated in both 2010 and 2012; median prevalence rates are summarized in the Table. MRSA prevalence did not vary across the country, but hospitals in eastern provinces had lower rates of VRE, whereas CDI rates were highest in central Canada. The prevalence of MRSA and CDI did not change over time, but there was an increase in VRE prevalence (median prevalence 0.5/100 inpatients in 2010, 1.25 in 2012; p=0.04). MRSA, VRE, and CDI were all predominantly healthcare-associated, but MRSA was more often community-associated (30%) than was VRE (6%) or CDI (23%) (p<0.001). ESBLs and CREs were reported from 71 (57%) and 10 (8%) hospitals respectively. Median prevalence per 100 inpatients (range) Organism 2010 2012 MRSA Colonization/infection 4.3 (0-22.1) 3.9 (0-26.8) Infection 0.3 (0-5.9) 0.3 (0-4.9) VRE Colonization/infection 0.5 (0-13.0) 1.3 (0-18.0) Infection 0 (0-0.8) 0 (0-1.5) ESBL - 0.7 (0-13.5) CRE - 0 (0-3.0) CDI 0.8 (0-8.6) 0.9 (0-5.5) Conclusion: These data provide national prevalence rates for MRSA, VRE, ESBLs, CREs, and CDI among adult inpatients in Canadian hospitals. A significant increase in VRE rates was observed from 2010 to 2012. MRSA and VRE were most often healthcare-associated, and from colonized patients identified by screening high-risk patients or high-risk inpatient units. CREs are currently infrequently identified in Canadian hospitals.
    IDWeek 2013 Meeting of the Infectious Diseases Society of America; 10/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: MRSA remains a leading cause of hospital-acquired (HAP) and healthcare-associated pneumonia (HCAP). We describe the epidemiology and outcome of MRSA pneumonia in Canadian hospitals, and identify factors contributing to mortality. Prospective surveillance for MRSA pneumonia in adults was done for one year (2011) in 11 Canadian hospitals. Standard criteria for MRSA HAP, HCAP, ventilator-associated pneumonia (VAP), and community-acquired pneumonia (CAP) were used to identify cases. MRSA isolates underwent antimicrobial susceptibility testing, and were characterized by pulsed-field gel electrophoresis (PFGE) and Panton-Valentine leukocidin (PVL) gene detection. The primary outcome was all-cause mortality at 30 days. A multivariable analysis was done to examine the association between various host and microbial factors and mortality. A total of 161 patients with MRSA pneumonia were identified: 90 (56%) with HAP, 26 (16%) HCAP, and 45 (28%) CAP; 23 (14%) patients had VAP. The mean (± SD) incidence of MRSA HAP was 0.32 (± 0.26) per 10,000 patient-days, and of MRSA VAP was 0.30 (± 0.5) per 1,000 ventilator-days. The 30-day all-cause mortality was 28.0%. In multivariable analysis, variables associated with mortality were the presence of multiorgan failure (OR 8.1; 95% CI 2.5-26.0), and infection with an isolate with reduced susceptibility to vancomycin (OR 2.5, 95% CI 1.0-6.3). MRSA pneumonia is associated with significant mortality. Severity of disease at presentation, and infection caused by an isolate with elevated MIC to vancomcyin are associated with increased mortality. Additional studies are required to better understand the impact of host and microbial variables on outcome.
    PLoS ONE 09/2013; 8(9):e75171. DOI:10.1371/journal.pone.0075171 · 3.53 Impact Factor

Publication Stats

8k Citations
1,296.31 Total Impact Points

Institutions

  • 1988–2015
    • University of Toronto
      • • Sunnybrook Health Sciences Centre
      • • Department of Laboratory Medicine and Pathobiology
      • • Department of Medicine
      • • Division of Infectious Diseases
      Toronto, Ontario, Canada
  • 1994–2014
    • Sunnybrook Health Sciences Centre
      • • Division of Infectious Diseases
      • • Division of Microbiology
      • • Division of Clinical Pharmacology and Toxicology
      • • Department of Medicine
      Toronto, Ontario, Canada
  • 2007–2012
    • Public Health Agency of Canada
      Ottawa, Ontario, Canada
    • University Health Network
      • Department of Medicine
      Toronto, Ontario, Canada
  • 2010
    • University of Guelph
      • Department of Pathobiology
      Guelph, Ontario, Canada
    • Massachusetts General Hospital
      Boston, Massachusetts, United States
  • 1993–2008
    • National Microbiology Laboratory, Canada
      Winnipeg, Manitoba, Canada
    • Baycrest
      Toronto, Ontario, Canada
  • 1999–2005
    • McMaster University
      • • Department of Pathology and Molecular Medicine
      • • Division of Infectious Diseases
      Hamilton, Ontario, Canada
    • The Princess Margaret Hospital
      Toronto, Ontario, Canada
  • 1989–2004
    • Mount Sinai Hospital, Toronto
      • Department of Microbiology
      Toronto, Ontario, Canada
  • 1996–2003
    • SickKids
      • Division of Infectious Diseases
      Toronto, Ontario, Canada
  • 1992
    • University of Manitoba
      Winnipeg, Manitoba, Canada
    • Mount Sinai Hospital
      New York City, New York, United States