Élise Fortin

A Portrait of the Geographic Dissemination of the Clostridium difficile North American Pulsed-Field Type 1 Strain and the Epidemiology of C. difficile-Associated Disease in Québec

BACKGROUND An increase in the incidence and severity of Clostridium difficile-associated disease in Québec and the United States has been associated with a hypervirulent strain referred to as North American pulsed-field type 1 (NAP1)/027. METHODS In 2005, a prospective study was conducted in 88 Québec hospitals, and 478 consecutive nosocomial isolates of C. difficile were obtained. The isolates were subjected to pulsed-field gel electrophoresis (PFGE) typing, antimicrobial susceptibility testing, and detection of binary toxin genes and tcdC gene deletion. Data on patient age and occurrence of complications were collected. RESULTS PFGE typing of 478 isolates of C. difficile yielded 61 PFGE profiles. Pulsovars A (57%), B (10%), and B1 (8%) were predominant. The PFGE profile of pulsovar A was identical to that of strain NAP1. It showed 67% relatedness with 15 other PFGE patterns, among which 11 had both binary toxin genes and a partial tcdC deletion but different antibiotic susceptibility profiles. Pulsovars B and B1 were identical to strain NAP2/ribotype 001. In hospitals showing a predominant clonal A or B-B1 PFGE pattern, incidence of C. difficile-associated disease was 2 and 1.3 times higher, respectively, than in hospitals without any predominant clonal PFGE pattern. Severe disease was twice as frequent among patients with strains possessing binary toxin genes and tcdC deletion than among patients with strains lacking these virulence factors. CONCLUSIONS This study helped to quantify the impact of strain NAP1 on the incidence and severity of C. difficile-associated disease in Québec in 2005. The identification of the geographic dissemination of this predominant strain may help to focus regional infection-control efforts.

Risk factors for hospitalization and severe outcomes of 2009 pandemic H1N1 influenza in Quebec, Canada.

Please cite this paper as: Gilca et al. (2011) Risk Factors for Hospitalization and Severe Outcomes of 2009 Pandemic H1N1 Influenza in Quebec, Canada. Influenza and Other Respiratory Viruses 5(4), 247–255

Epidemiological patterns and hospital characteristics associated with increased incidence of Clostridium difficile infection in Quebec, Canada, 1998-2006.

OBJECTIVE To explore epidemiological patterns of the incidence of Clostridium difficile infection (CDI) and hospital characteristics associated with increased incidence during nonepidemic and epidemic years. DESIGN Retrospective and prospective ecological study. SETTING Eighty-three acute care hospitals participating in CDI surveillance in the province of Quebec, Canada. METHODS A Serfling-type regression model applied to data obtained from an administrative database (1998-2006) and prospective Quebec CDI surveillance (2004-2006) was used to calculate expected CDI baseline incidence and to detect incidence exceeding the defined epidemic threshold at the provincial and hospital level. Multivariable Poisson regression was used to determine hospital characteristics associated with increased incidence during nonepidemic (1998-2001) and epidemic (2003-2005) periods. RESULTS During the study period (1998-2006), 4,525,847 discharges, including 45,508 with a CDI in any diagnosis field, were reported by 83 hospitals. During 1998-2001, the average Quebec incidence of CDI was 10,304 cases in 1,775,822 discharges (5.8 cases per 1,000 discharges) and presented a pattern of seasonality, with similar patterns at the hospital level for some hospitals. The Quebec epidemic started in October-November 2002 and peaked in March 2004 at 845 cases in 40,852 discharges (20.7 cases per 1,000 discharges). In multivariable analysis, higher incidence was associated with location in Montreal and surrounding regions, greater hospital size, larger proportion of hospitalized elderly patients, longer length of stay, and greater proportion of comorbidities in patients, whereas teaching profile was associated with decreased incidence during both nonepidemic and epidemic periods. The effect of geographical location on incidence was greater during the epidemic. CONCLUSION Baseline incidence from nonepidemic years and hospital characteristics associated with CDI incidence should be taken into account when estimating the efficacy of interventions.

Seasonal Variations in Clostridium difficile Infections Are Associated with Influenza and Respiratory Syncytial Virus Activity Independently of Antibiotic Prescriptions: a Time Series Analysis in Québec, Canada

ABSTRACT Seasonal variations in Clostridium difficile-associated diarrhea (CDAD), with a higher incidence occurring during winter months, have been reported. Although winter epidemics of respiratory viruses may be temporally associated with an increase in CDAD morbidity, we hypothesized that this association is mainly due to increased antibiotic use for respiratory infections. The objective of this study was to evaluate the effect of the two most frequent respiratory viruses (influenza virus and respiratory syncytial virus [RSV]) and antibiotics prescribed for respiratory infections (fluoroquinolones and macrolides) on the CDAD incidence in hospitals in the province of Québec, Canada. A multivariable Box-Jenkins transfer function model was built to relate monthly CDAD incidence to the monthly percentage of positive tests for influenza virus and RSV and monthly fluoroquinolone and macrolide prescriptions over a 4-year period (January 2005 to December 2008). Analysis showed that temporal variations in CDAD incidence followed temporal variations for influenza virus (P = 0.043), RSV (P = 0.004), and macrolide prescription (P = 0.05) time series with an average delay of 1 month and fluoroquinolone prescription time series with an average delay of 2 months (P = 0.01). We conclude that influenza virus and RSV circulation is independently associated with CDAD incidence after controlling for fluoroquinolone and macrolide use. This association was observed at an aggregated level and may be indicative of other phenomena occurring during wintertime.

Healthcare-associated bloodstream infections secondary to a urinary focus: the Québec provincial surveillance results.

OBJECTIVE Urinary tract infections (UTIs) are an important source of secondary healthcare-associated bloodstream infections (BSIs), where a potential for prevention exists. This study describes the epidemiology of BSIs secondary to a urinary source (U-BSIs) in the province of Québec and predictors of mortality. DESIGN Dynamic cohort of 9,377,830 patient-days followed through a provincial voluntary surveillance program targeting all episodes of healthcare-associated BSIs occurring in acute care hospitals. SETTING Sixty-one hospitals in Québec, followed between April 1, 2007, and March 31, 2010. PARTICIPANTS Patients admitted to participating hospitals for 48 hours or longer. METHODS Descriptive statistics were used to summarize characteristics of U-BSIs and microorganisms involved. Wilcoxon and χ(2) tests were used to compare U-BSI episodes with other BSIs. Negative binomial regression was used to identify hospital characteristics associated with higher rates. We explored determinants of mortality using logistic regression. RESULTS Of the 7,217 reported BSIs, 1,510 were U-BSIs (21%), with an annual rate of 1.4 U-BSIs per 10,000 patient-days. A urinary device was used in 71% of U-BSI episodes. Identified institutional risk factors were average length of stay, teaching status, and hospital size. Increasing hospital size was influential only in nonteaching hospitals. Age, nonhematogenous neoplasia, Staphylococcus aureus, and Foley catheters were associated with mortality at 30 days. CONCLUSION U-BSI characteristics suggest that urinary catheters may remain in patients for ease of care or because practitioners forget to remove them. Ongoing surveillance will enable hospitals to monitor trends in U-BSIs and impacts of process surveillance that will be implemented shortly.

Epidemiology of central line–associated bloodstream infections in Quebec intensive care units: A 6-year review

BACKGROUND The burden of central line-associated bloodstream infections (CLABSI) in Canadian intensive care units (ICUs) is not well established. The present study aimed to describe CLABSI epidemiology in Quebec ICUs during 2003-2009. METHODS The study population was a retrospective dynamic cohort of 58 ICUs that participated in the Surveillance Provinciale des Infections Nosocomiales program during 2003-2009. We calculated annual CLABSI incidence rates (IRs), central venous catheter (CVC) utilization ratios, and case-fatality proportions, and described the pathogens involved. We analyzed data using descriptive statistics and standardized incidence ratios. RESULTS A total of 891 CLABSIs were identified during 446,137 CVC-days. In 2003-2009, CLABSI IRs were 1.67 CLABSI/1,000 CVC-days in adult ICUs, 2.20 CLABSIs/1,000 CVC-days in pediatric ICUs, and 4.40 CLABSIs/1,000 CVC-days in neonatal ICUs. Since 2007, CLABSI IRs in adult, pediatric and neonatal ICUs have decreased by 11%, 50%, and 18%, respectively. Pediatric ICUs had the highest CVC utilization ratio (median, 0.61; interquartile range, 0.57-0.66). Coagulase-negative staphylococci caused 53% of the CLABSIs. The proportion of methicillin-resistant Staphylococcus aureus declined from 70% to <40% after 2006. CONCLUSIONS CLABSIs result in a considerable burden of illness in Quebec ICUs. However, CLABSI IRs have decreased since 2007, and the proportion of methicillin-resistant S aureus has remained <40% since 2006. Continuous surveillance is essential to determine whether these changes are sustainable.

Central line-associated bloodstream infection in neonatal intensive care units.

OBJECTIVE Describe the epidemiology of central line-associated bloodstream infections (CLABSIs) in neonatal intensive care units (NICUs) participating in a standardized and mandatory CLABSI surveillance program. DESIGN Retrospective cohort. Setting. We included patients admitted (April 2007-March 2011) to 7 level II/III NICUs who developed a CLABSI (as defined by the National Healthcare Safety Network). METHODS CLABSIs/1,000 central line-days and device utilization ratio were calculated; χ(2) test, Student t test, Kruskal-Wallis, and Poisson regression were used. RESULTS Overall, 191 patients had 202 CLABSI episodes for a pooled mean rate of 4.0 CLABSIs/1,000 central line-days and a device utilization ratio of 0.20. Annual pooled mean CLABSI rates increased from 3.6 in 2007-2008 to 5.1 CLABSIs/1,000 central line-days in 2010-2011 (P - .01). The all-cause 30-day case fatality proportion was 8.9% (n = 17) and occurred a median of 8 days after CLABSI. Coagulase-negative Staphylococcus was identified in 112 (50.5%) cases. Staphylococcus aureus was identified in 22 cases, and 3 (13.6%) were resistant to methicillin. An underlying intra-abdominal pathology was found in 20% (40/202) of CLABSI cases, 50% of which were reported in the last year of study. When adjusted for mean birth weight, annual CLABSI incidence rates were independently associated with the proportion of intra-abdominal pathology (P = .007) and the proportion of pulmonary pathology (P = .016) reported. CONCLUSION The increase in CLABSI rates in Quebec NICUs seems to be associated with an increased proportion of cases with underlying intra-abdominal and pulmonary pathologies, which needs further investigation.

Measuring antimicrobial use in hospitalized patients: a systematic review of available measures applicable to paediatrics

OBJECTIVES The optimal measure to use for surveillance of antimicrobial usage in hospital settings, especially when including paediatric populations, is unknown. This systematic review of literature aims to list, define and compare existing measures of antimicrobial use that have been applied in settings that included paediatric inpatients, to complement surveillance of resistance. METHODS We identified cohort studies and repeated point-prevalence studies presenting data on antimicrobial use in populations of inpatients or validations/comparisons of antimicrobial measures through a systematic search of literature using MEDLINE, EMBASE, CINAHL and LILACS (1975-2011) and citation tracking. Study populations needed to include hospitalized paediatric patients. Two reviewers independently extracted data on study characteristics and results. RESULTS Overall, 3878 records were screened and 79 studies met selection criteria. Twenty-six distinct measures were found, the most frequently used being defined daily doses (DDD)/patient-days and exposed patients/patients. Only two studies compared different measures quantitatively, showing (i) a positive correlation between proportion of exposed patients and antimicrobial-days/patient-days and (ii) a strong correlation between doses/patient-days and agent-days/patient-days (r = 0.98), with doses/patient-days correlating more with resistance rates (r = 0.80 versus 0.55). CONCLUSIONS The measure of antimicrobial use that best predicts antimicrobial resistance prevalence and rates, for surveillance purposes, has still not been identified; additional evidence on this topic is a necessity.

A survey of Preventive Measures Used and their Impact on Central Line-Associated Bloodstream Infections (CLABSI) in Intensive Care Units (SPIN-BACC)

BackgroundThe Quebec central line-associated bloodstream infections (CLABSI) in intensive care units (ICUs) Surveillance Program saw a decrease in CLABSI rates in most ICUs. Given the surveillance trends observed in recent years, we aimed to determine what preventive measures have been implemented, if compliance to measures was monitored and its impact on CLABSI incidence rates.MethodsAll hospitals participating in the Quebec healthcare-associated infections surveillance program (SPIN-BACC – n = 48) received a 77-question survey about preventive measures implemented and monitored in their ICU. The questionnaire was validated for construct, content, face validity, and reliability. We used Poisson regression to measure the association between compliance monitoring to preventive measures and CLABSI rates.ResultsForty-two (88%) eligible hospitals completed the survey. Two components from the maximum barrier precautions were used less optimally: cap (88%) and full sterile body drape (71%). Preventive measures reported included daily review of catheter need (79%) and evaluation of insertion site for the presence of inflammation (90%). Two hospitals rewired lines even if an infection was suspected or documented.In adult ICUs, there was a statistically significant greater decrease in CLABSI rates in ICUs that monitored compliance to preventive insertion measures, after adjusting for teaching status and the number of hospital beds (p = 0.036).ConclusionsHospitals participating to the SPIN-BACC program follow recommendations for CLABSI prevention, but only a minority locally monitor their application. Compliance monitoring of preventive measures for catheter insertion was associated with a decrease in CLABSI incidence rates.

Attributing cause of death for patients with Clostridium difficile infection.

To the Editor: Hota et al. report that for deceased patients who had Clostridium difficile infection (CDI), agreement is poor between causes of death reported on death certificates and those categorized by a review panel (1). Our data support the difficulty of attributing cause of death for patients with CDI. In 2004 in Quebec, Canada, a mandatory CDI surveillance program was implemented. Deaths that occurred within 30 days after CDI diagnosis were classified as 1) directly attributable to CDI (e.g., toxic megacolon, septic shock), 2) having a CDI contribution (e.g., acute decompensation of chronic heart failure), or 3) unrelated to CDI (e.g., terminal cancer) (2). To determine accuracy of the surveillance classifications, we compared cause-of-death classification of 22 deceased CDI patients reported to surveillance by 1 hospital in 2007 with causes of death reported by 13 external reviewers who examined summaries of medical files of the deceased patients. Reviewers were 11 infectious disease and 2 public health physicians involved with CDI surveillance at their respective hospitals but not this hospital. The median (minimal, maximal) κ statistics for comparison of external reviews with surveillance classification were 0.495 (0.252, 0.607) for directly attributable, 0.182 (−0.091, 0.182) for contributed, and 0.321 (0.124, 0.614) for unrelated. Comparison within external reviewers yielded 0.697 (0.394, 1.0), 0.233 (−0.294, 0.703), and 0.542 (0.154, 0.909), respectively. Complete agreement was found for only 6 cases (4 directly attributable and 2 unrelated) (Figure). Figure Classification of cause of death among 22 patients with Clostridium difficile infection (CDI), by 13 external reviewers, Quebec, Canada, 2007. Bars indicate the number of reviewers who assigned each category. Gray bars indicate that CDI was unrelated ... Variation among reviewers suggested that categorizations reported to surveillance were inaccurate. Number of deaths among patients with CDI, regardless of the cause of death, seemed to better indicate CDI severity. Since 2008, only the crude numbers of deaths, not subjected to individual interpretation, have been reported to surveillance. A questionnaire addressing concurrent medical conditions, prognosis, level of care, and circumstances of death is being implemented in Quebec hospitals participating in CDI surveillance and should help determine the role of CDI in deaths.