The Strain and the Clinical Outcome of Clostridioides difficile Infection: A Meta-analysis

Background

The association between bacterial strains and clinical outcomes in Clostridioides difficile infection (CDI) has yielded conflicting results across studies. We conducted a systematic review and meta-analyses to assess the impact of these strains.

Methods

Five electronic databases were used to identify studies reporting CDI severity, complications, recurrence, or mortality according to strain type from inception to June 2022. Random effect meta-analyses were conducted to assess outcome proportions and risk ratios (RRs).

Results

A total of 93 studies were included: 44 reported recurrences, 50 reported severity or complications, and 55 reported deaths. Pooled proportions of complications were statistically comparable between NAP1/BI/R027 and R001, R078, and R106. Pooled attributable mortality was 4.8% with a gradation in patients infected with R014/20 (1.7%), R001 (3.8%), R078 (5.3%), and R027 (10.2%). Higher 30-day all-cause mortality was observed in patients infected with R001, R002, R027, and R106 (range, 20%-25%).NAP1/BI/R027 was associated with several unfavorable outcomes: recurrence 30 days after the end of treatment (pooled RR, 1.98; 95% CI, 1.02-3.84); admission to intensive care, colectomy, or CDI-associated death (1.88; 1.09-3.25); and 30-day attributable mortality (1.96; 1.23-3.13). The association between harboring the binary toxin gene and 30-day all-cause mortality did not reach significance (RR, 1.6 [0.9-2.9]; 7 studies).

Conclusions

Numerous studies were excluded due to discrepancies in the definition of the outcomes and the lack of reporting of important covariates. NAP1/BI/R027, the most frequently reported and assessed strain, was associated with unfavorable outcomes. However, there were not sufficient data to reach significant conclusions on other strains.

Chronic Diarrhea Caused by a Klebsiella oxytoca Toxin Producer Strain Following Antibiotic-Associated Hemorrhagic Colitis: Successful Treatment by Fecal Microbiota Transplant

Klebsiella oxytoca is a gram-negative bacterium found in fecal microbiota and known to cause several infections in humans, including antibiotic-associated hemorrhagic colitis. We present here a case of colitis caused by K. oxytoca toxin-producing strains that evolved in chronic diarrhea successfully treated by fecal microbiota transplant.

Vaccine Effectiveness of non-adjuvanted and adjuvanted trivalent inactivated influenza vaccines in the prevention of influenza-related hospitalization in older adults: A pooled analysis from the Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN)

BACKGROUND

Influenza vaccines prevent influenza-related morbidity and mortality; however, suboptimal vaccine effectiveness (VE) of non-adjuvanted trivalent inactivated influenza vaccine (naTIV) or quadrivalent formulations in older adults prompted the use of enhanced products such as adjuvanted TIV (aTIV). Here, the VE of aTIV is compared to naTIV for preventing influenza-associated hospitalization among older adults.

METHODS

A test-negative design study was used with pooled data from the 2012 to 2015 influenza seasons. An inverse probability of treatment (IPT)-weighted logistic regression estimated the Odds Ratio (OR) for laboratory-confirmed influenza-associated hospitalization. VE was calculated as (1-OR)*100% with accompanying 95% confidence intervals (CI).

RESULTS

Of 7,101 adults aged ≥ 65, 3,364 received naTIV and 526 received aTIV. The overall VE against influenza hospitalization was 45.9% (95% CI: 40.2%-51.1%) for naTIV and 53.5% (42.8%-62.3%) for aTIV. No statistically significant differences in VE were found between aTIV and naTIV by age group or influenza season, though a trend favoring aTIV over naTIV was noted. Frailty may have impacted VE in aTIV recipients compared to those receiving naTIV, according to an exploratory analysis; VE adjusted by frailty was 59.1% (49.6%-66.8%) for aTIV and 44.8% (39.1%-50.0%) for naTIV. The overall relative VE of aTIV to naTIV against laboratory-confirmed influenza hospital admission was 25% (OR 0.75; 0.61-0.92), demonstrating statistically significant benefit favoring aTIV.

CONCLUSIONS

Adjusting for frailty, aTIV showed statistically significantly better protection than naTIV against influenza-associated hospitalizations in older adults. In future studies, it is important to consider frailty as a significant confounder of VE.

Leveraging Influenza Virus Surveillance From 2012 to 2015 to Characterize the Burden of Respiratory Syncytial Virus Disease in Canadian Adults ≥50 Years of Age Hospitalized With Acute Respiratory Illness

Background

Respiratory syncytial virus (RSV) disease in older adults is undercharacterized. To help inform future immunization policies, this study aimed to describe the disease burden in Canadian adults aged ≥50 years hospitalized with RSV.

Methods

Using administrative data and nasopharyngeal swabs collected from active surveillance among adults aged ≥50 years hospitalized with an acute respiratory illness (ARI) during the 2012-2013, 2013-2014, and 2014-2015 influenza seasons, RSV was identified using a respiratory virus multiplex polymerase chain reaction test to describe the associated disease burden, incidence, and healthcare costs.

Results

Of 7797 patients tested, 371 (4.8%) were RSV positive (2.2% RSV-A and 2.6% RSV-B). RSV prevalence varied by season from 4.2% to 6.2%. Respiratory virus coinfection was observed in 11.6% (43/371) of RSV cases, with influenza A being the most common. RSV hospitalization rates varied between seasons and increased with age, from 8-12 per 100 000 population in adults aged 50-59 years to 174-487 per 100 000 in adults aged ≥80 years. The median age of RSV cases was 74.9 years, 63.7% were female, and 98.1% of cases had ≥1 comorbidity. Among RSV cases, the mean length of hospital stay was 10.6 days, 13.7% were admitted to the intensive care unit, 6.4% required mechanical ventilation, and 6.1% died. The mean cost per RSV case was $13 602 (Canadian dollars) but varied by age and Canadian province.

Conclusions

This study adds to the growing literature on adult RSV burden by showing considerable morbidity, mortality, and healthcare costs in hospitalized adults aged ≥50 years with ARIs such as influenza.

Adverse Events Following Immunization With mRNA and Viral Vector Vaccines in Individuals With Previous Severe Acute Respiratory Syndrome Coronavirus 2 Infection From the Canadian National Vaccine Safety Network

BACKGROUND

Adults previously infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) develop short-term immunity and may have increased reactogenicity to coronavirus disease 2019 (COVID-19) vaccines. This prospective, multicenter, active-surveillance cohort study examined the short-term safety of COVID-19 vaccines in adults with a prior history of SARS-CoV-2.

METHODS

Canadian adults vaccinated between 22 December 2020 and 27 November 2021 were sent an electronic questionnaire 7 days post-dose 1, dose 2, and dose 3 vaccination. The main outcome was health events occurring in the first 7 days after each vaccination that prevented daily activities, resulted in work absenteeism, or required a medical consultation, including hospitalization.

RESULTS

Among 684 998 vaccinated individuals, 2.6% (18 127/684 998) reported a prior history of SARS-CoV-2 infection a median of 4 (interquartile range: 2-6) months previously. After dose 1, individuals with moderate (bedridden) to severe (hospitalized) COVID-19 who received BNT162b2, mRNA-1273, or ChAdox1-S vaccines had higher odds of a health event preventing daily activities, resulting in work absenteeism or requiring medical consultation (adjusted odds ratio [95% confidence interval]: 3.96 [3.67-4.28] for BNT162b2, 5.01 [4.57-5.50] for mRNA-1273, and 1.84 [1.54-2.20] for ChAdox1-S compared with no infection). Following dose 2 and 3, the greater risk associated with previous infection was also present but was attenuated compared with dose 1. For all doses, the association was lower or absent after mild or asymptomatic infection.

CONCLUSIONS

Adults with moderate or severe previous SARS-CoV-2 infection were more likely to have a health event sufficient to impact routine activities or require medical assessment in the week following each vaccine dose.

Older Age and Frailty are Associated with Higher Mortality but Lower ICU Admission with COVID-19

Background

We report characteristics and outcomes of adults admitted to Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Network hospitals with COVID-19 in 2020.

Methods

Patients with laboratory-confirmed COVID-19 admitted to 11 sites in Ontario, Quebec, Alberta, and Nova Scotia up to December 31, 2020 were enrolled in this prospective observational cohort study. Measures included age, sex, demographics, housing, exposures, Clinical Frailty Scale, comorbidities; in addition, length of stay, intensive care unit (ICU) admission, mechanical ventilation, and survival were assessed. Descriptive analyses and multivariable logistic regressions were conducted.

Results

Among 2,011 patients, mean age was 71.0 (range 19–105) years. 29.7% were admitted from assisted living or long-term care facilities. The full spectrum of frailty was represented in both younger and older age groups. 81.8% had at least one underlying comorbidity and 27.2% had obesity. Mortality was 14.3% without ICU admission, and 24.6% for those admitted to ICU. Older age and frailty were independent predictors of lower ICU use and higher mortality; accounting for frailty, obesity was not an independent predictor of mortality, and associations of comorbidities with mortality were weakened.

Conclusions

Frailty is a critical clinical factor in predicting outcomes of COVID-19, which should be considered in research and clinical settings.

Management and clinical outcomes of Lyme disease in acute care facilities in 2 endemic regions of Quebec, Canada: a multicentre retrospective cohort study

BACKGROUND

Despite increases in cases of Lyme disease, little is known about the management and clinical course of the disease in Canada. We aimed to describe the management and clinical course of Lyme disease in patients treated in acute care facilities in Quebec and to assess adherence to the 2006 Infectious Diseases Society of America (IDSA) guideline.

METHODS

This retrospective multicentre cohort study included pediatric and adult patients with serologically confirmed Lyme disease treated in acute care facilities (12 community hospitals and 2 tertiary care centres) of 2 endemic regions of Quebec (Estrie and Montérégie), from 2004 to 2017. We considered drug choice, prescribed dose and treatment duration in assessing adherence of prescriptions to the 2006 IDSA guideline. The main outcome was complete resolution of symptoms at 3 months after the initiation of treatment.

RESULTS

We included 272 patients from 14 institutions (age range 3-87 yr). Early disseminated Lyme disease (140 patients [51%]) was predominant. Adherence to the IDSA guideline was observed in 235 (90%) of the 261 cases with complete information, and adherence was stable over time (2004-2013: 57/64 [89%]; 2014-2015: 64/71 [90%]; 2016-2017: 114/126 [90%]; p = 0.8). Non-adherence to the guideline (n = 26) was predominantly due to longer-than-recommended treatment duration (16/26 [62%]). Resolution of objective signs at 3 months after treatment initiation occurred in 265 (99%) of 267 patients, whereas post-treatment Lyme disease syndrome was observed in 27 patients (10%) with increasing incidence over time (2004-2013: 3/65 [5%]; 2014-2015: 4/73 [5%]; 2016-2017: 20/129 [16%]; p = 0.02).

INTERPRETATION

We observed clinical resolution of Lyme disease in 99% of the patients, and most treatments (90%) complied with the 2006 IDSA guideline. The incidence of post-treatment Lyme disease syndrome increased over the study period, warranting further prospective studies.

The Canadian National Vaccine Safety Network: surveillance of adverse events following immunisation among individuals immunised with the COVID-19 vaccine, a cohort study in Canada

INTRODUCTION

COVID-19 vaccines require enhanced safety monitoring after emergency approval. The Canadian National Vaccine Safety Network monitors the safety of COVID-19 vaccines and provides enhanced monitoring for healthy, auto-immune, immunocompromised, pregnant and breastfeeding populations and allows for the detection of safety signals.

METHODS AND ANALYSIS

Online participant reporting of health events in vaccinated and unvaccinated individuals 12 years of age and older is captured in three surveys: 1 week after dose 1, 1 week after dose 2 and 7 months after dose 1. Medically attended events are followed up by telephone. The number, percentage, rate per 10 000 and incident rate ratios with 95% CIs are calculated by health event, vaccine type, sex and in 10-year age groups.

ETHICS AND DISSEMINATION

Each study site has Research Ethics Board approvals for the project (UBC Children's & Women's, CIUSSS de l'Estrie-CHUS, Health PEI, Conjoint Health Research Ethics Board, University of Calgary and Alberta Health Services, IWK Health, Unity Health Toronto and CHU de Québec-Université Laval Research Ethics Boards). Individuals are invited to participate in this active surveillance and electronic consent is given before proceeding to each survey. Weekly reports are shared with public health and posted on the study website. At least one peer-reviewed manuscript is produced.

Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its first variants in fourplex real-time quantitative reverse transcription-PCR assays

The early diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is required to identify and isolate contagious patients to prevent further transmission of SARS-CoV-2. In this study, we present a multitarget real-time TaqMan reverse transcription PCR (rRT-PCR) assay for the quantitative detection of SARS-CoV-2 and some of its circulating variants harboring mutations that give the virus a selective advantage. Seven different primer-probe sets that included probes containing locked nucleic acid (LNA) nucleotides were designed to amplify specific wild-type and mutant sequences in Orf1ab, Envelope (E), Spike (S), and Nucleocapsid (N) genes. Furthermore, a newly developed primer-probe set targeted human β₂-microglobulin (B2M) as a highly sensitive internal control for RT efficacy. All singleplex and fourplex assays detected ≤ 14 copies/reaction of quantified synthetic RNA transcripts, with a linear amplification range of nine logarithmic orders. Primer-probe sets for detection of SARS-CoV-2 exhibited no false-positive amplifications with other common respiratory pathogens, including human coronaviruses NL63, 229E, OC43, and HKU-1. Fourplex assays were evaluated using 160 clinical samples positive for SARS-CoV-2. Results showed that SARS-CoV-2 viral RNA was detected in all samples, including viral strains harboring mutations in the Spike coding sequence that became dominant in the pandemic. Given the emergence of SARS-CoV-2 variants and their rapid spread in some populations, fourplex rRT-PCR assay containing four primer-probe sets represents a reliable approach to allow quicker detection of circulating relevant variants in a single reaction.

1325. Recalibrating Estimates of Pneumococcal Disease in Hospitalized Canadian adults from 2010 to 2017 with Use of an Extended Spectrum Serotype-specific Urine Antigen Detection

Background

Pneumococcal vaccine recommendations in Canada include both age- and risk-based guidance. This study aimed to describe the burden of vaccine-preventable pneumococcal community acquired pneumonia (pCAP) and invasive pneumococcal disease (IPD) by age in hospitalized adults.

Methods

Active surveillance for all-cause CAP and IPD in hospitalized adults was performed from 2010 to 2017, including laboratory results, patient demographics, and outcomes. Streptococcus pneumoniae was detected using blood and sputum culture, or urine antigen detection (UAD). Serotype was assigned using Quellung reaction, PCR, or serotype-specific UADs spanning the 24 serotypes in PCV13 and PPV23 vaccines. Data were categorized by age (16-49, 50-64, 65+, and 50+ years) and over time.

Results

11129 ACP cases and 216 cases of IPD (non-CAP) were identified. A laboratory test for S. pneumoniae was performed in 8912 of ACP cases, identifying 1264 (14.2%) as pCAP. Compared to non-pCAP, pCAP cases were more likely to be admitted to intensive care units and require mechanical ventilation. These serious outcomes, as well as mortality, were more prominent in bacteremic pCAP and IPD. Risk factors for death in pCAP included aged 75+ years, immune compromising conditions, and BMI < 18.5. When categorized by age, the proportion of individuals aged 65+ years for pCAP and IPD was 49.8% and 48.6%, and the 50-64 year age cohort represented 31.3% and 29.9%, respectively. The contributions of PCV13 and PPV23 serotypes remained relatively stable over time, and overall represented 57.6% and 90.9% for pCAP, and 35.0% and 72.0% for IPD, respectively.

Conclusion

Seven years following infant PCV13 immunization programs in Canada, PCV13 and PPV23 serotypes in pCAP and IPD remained predominant causes of pneumococcal disease. Serious outcomes were particularly evident in adults 50+, suggesting pneumococcal vaccines should be encouraged in this age group.

Disclosures

Jason J. LeBlanc, PhD, FCCM, D[ABMM], GSK (Research Grant or Support)Merck (Grant/Research Support)Pfizer (Grant/Research Support) Todd F Hatchette, MD, GSK (Grant/Research Support)Pfizer (Grant/Research Support) Melissa K. Andrew, MD, PhD, GSK (Grant/Research Support)Pfizer (Grant/Research Support, Advisor or Review Panel member)Sanofi (Consultant, Grant/Research Support, Advisor or Review Panel member)Seqirus (Advisor or Review Panel member) Allison McGeer, MSc,MD,FRCPC,FSHEA, GlaxoSmithKline (Advisor or Review Panel member)Merck (Advisor or Review Panel member, Research Grant or Support)Pfizer (Grant/Research Support, Scientific Research Study Investigator, Advisor or Review Panel member) Louis Valiquette, MD, M.Sc., Cubist (Consultant)GSK (Grant/Research Support)Merck (Consultant)Optimer (Consultant)Pfizer (Grant/Research Support) Shelly McNeil, FRCPC, MD, GSK (Grant/Research Support)Pfizer (Grant/Research Support)Sinofi Pasteur (Grant/Research Support)

The 2018 Global Point Prevalence Survey of antimicrobial consumption and resistance in 47 Canadian hospitals: a cross-sectional survey

BACKGROUND

Patient-level surveillance of antimicrobial use (AMU) in Canadian hospitals empowers the reduction of inappropriate AMU and was piloted in 2017 among 14 hospitals in Canada. We aimed to describe AMU on the basis of patient-level data in Canadian hospitals in 2018 in terms of antimicrobial prescribing prevalence and proportions, antimicrobial indications, and agent selection in medical, surgical and intensive care wards.

METHODS

Canadian adult, pediatric and neonatal hospitals were invited to participate in the standardized web-based cross-sectional Global Point Prevalence Survey of Antimicrobial Consumption and Resistance (Global-PPS) conducted in 2018. An identified site administrator assigned all wards admitting inpatients to specific surveyors. A physician, pharmacist or nurse with infectious disease training performed the survey. The primary outcomes were point prevalence rates for AMU over the study period regarding prescriptions, indications and agent selection in medical, surgical and intensive care wards. The secondary outcomes were AMU for resistant organisms and practice appropriateness evaluated on the basis of quality indicators. Antimicrobial consumption is presented in terms of prevalence and proportions.

RESULTS

Forty-seven of 118 (39.8%) hospitals participated in the survey; 9 hospitals were primary care centres, 15 were secondary care centres and 23 were tertiary or specialized care centres. Of 13 272 patients included, 33.5% (n = 4447) received a total of 6525 antimicrobials. Overall, 74.1% (4832/6525) of antimicrobials were for therapeutic use, 12.6% (n = 825) were for medical prophylaxis, 8.9% (n = 578) were for surgical prophylaxis, 2.2% (n = 143) were for other use and 2.3% (n = 147) were for unidentified reasons. A diagnosis or indication was documented in the patient's file at the initiation for 87.3% (n = 5699) of antimicrobials; 62.9% (n = 4106) of antimicrobials had a stop or review date; and 72.0% (n = 4697) of prescriptions were guided by local guidelines.

INTERPRETATION

Overall, three-quarters of AMU was for therapeutic use across participating hospitals. Canadian hospitals should be further incentivized to create and adapt local guidelines on the basis of recent antimicrobial resistance data.

Impact of a hospital-wide computerised approach to optimise the quality of antimicrobial prescriptions in patients with severe obesity: a quasi-experimental study

Background

Rates of adherence to available recommendations for dose adjustments in patients with severe obesity are generally low. Hence, antimicrobials are often underdosed in these patients. Antimicrobial stewardship programmes can improve the use of antimicrobials in hospitalised patients. The aim of the study was to analyse the impact of an antimicrobial stewardship programme based on a computerised clinical decision support system for optimal dosing and antimicrobial use in inpatients with severe obesity.

Methods

This quasi-experimental retrospective study using interrupted time series was conducted in an academic centre in Canada from August 2008 to June 2018. The Antimicrobial Prescription Surveillance System was implemented in August 2010 (intervention 1) and specific rules targeting patients with class III obesity (body mass index ≥ 40 kg/m²) were added in June 2014 (intervention 2). Data were collected from all hospitalised adults receiving antimicrobials which required dose adjustment for severe obesity and were stratified by body mass index. Segmented regression analysis of interrupted time series was used to evaluate the impact of the Antimicrobial Prescription Surveillance System on the proportion of inappropriate days of therapy according to posology and on antimicrobial consumption.

Results

Overall, 65 205 antimicrobial prescriptions (68% non-obese, 25% class I-II obesity, and 7% class III obesity) were analysed. In patients with class III obesity, the intervention was associated with a decrease in the proportion of inappropriate days of therapy (trend after the first intervention, −0.8% per 2-month period [95% CI −1.1 to −0.5], p < 0.001; intercept, 11.3% [95% CI 8.2 to 14.5], p < 0.001), which led to a reduction of 35% over an eight-year period (from pre-intervention level of 19.1%). Intervention 1 resulted in a downward trend in antimicrobial consumption, followed by an increasing trend after intervention 2. In these patients, the most frequent interventions made by pharmacists targeted posology (46%).

Conclusions

Antimicrobial Prescription Surveillance System had a positive impact on dosing optimisation and antimicrobial consumption in patients with class III obesity. Improving antimicrobial prescriptions in these patients is important because suboptimal dosing could be associated with unfavourable outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06682-8.

Increasing incidence and antimicrobial resistance in Escherichia coli bloodstream infections: a multinational population-based cohort study

BACKGROUND

Escherichia coli is an important pathogen in humans and is the most common cause of bacterial bloodstream infections (BSIs). The objectives of our study were to determine factors associated with E. coli BSI incidence rate and third-generation cephalosporin resistance in a multinational population-based cohort.

METHODS

We included all incident E. coli BSIs (2014-2018) from national (Finland) and regional (Australia [Canberra], Sweden [Skaraborg], and Canada [Calgary, Sherbrooke, and western interior]) surveillance. Incidence rates were directly age and sex standardized to the European Union 28-country 2018 population. Multivariable negative binomial and logistic regression models estimated factors significantly associated with E. coli BSI incidence rate and third-generation cephalosporin resistance, respectively. The explanatory variables considered for inclusion in both models were year (2014-2018), region (six areas), age (< 70-years-old and ≥ 70-years-old), and sex (female and male).

RESULTS

We identified 31,889 E. coli BSIs from 40.7 million person-years of surveillance. Overall and third-generation cephalosporin-resistant standardized rates were 87.1 and 6.6 cases/100,000 person-years, respectively, and increased 14.0% and 40.1% over the five-year study. Overall, 7.8% (2483/31889) of E. coli BSIs were third-generation cephalosporin-resistant. Calgary, Canberra, Sherbrooke, and western interior had significantly lower E. coli BSI rates compared to Finland. The significant association between age and E. coli BSI rate varied with sex. Calgary, Canberra, and western interior had significantly greater odds of third-generation cephalosporin-resistant E. coli BSIs compared to Finland. Compared to 2014, the odds of third-generation cephalosporin-resistant E. coli BSIs were significantly increased in 2016, 2017, and 2018. The significant association between age and the odds of having a third-generation cephalosporin-resistant E. coli BSI varied with sex.

CONCLUSIONS

Increases in overall and third-generation cephalosporin-resistant standardized E. coli BSI rates were clinically important. Overall, E. coli BSI incidence rates were 40-104% greater than previous investigations from the same study areas. Region, sex, and age are important variables when analyzing E. coli BSI rates and third-generation cephalosporin resistance in E. coli BSIs. Considering E. coli is the most common cause of BSIs, this increasing burden and evolving third-generation cephalosporin resistance will have an important impact on human health, especially in aging populations.

Does BCG provide long-term protection against SARS-CoV-2 infection? A case-control study in Quebec, Canada

Background

Early in the coronavirus disease 2019 (COVID-19) pandemic, before severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines became available, it was hypothesized that BCG (Bacillus Calmette–Guérin), which stimulates innate immunity, could provide protection against SARS-CoV-2. Numerous ecological studies, plagued by methodological deficiencies, revealed a country-level association between BCG use and lower COVID-19 incidence and mortality. We aimed to determine whether BCG administered in early life decreased the risk of SARS-CoV-2 infection in adulthood and the severity of COVID-19.

Methods

This case-control study was conducted in Quebec, Canada. Cases were patients with a positive SARS-CoV-2 nucleic acid amplification test performed at two hospitals between March–October 2020. Controls were identified among patients with non-COVID-19 samples processed by the same microbiology laboratories during the same period. Enrolment was limited to individuals born in Quebec between 1956 and 1976, whose vaccine status was accessible in a computerized registry of 4.2 million BCG vaccinations.

Results

We recruited 920 cases and 2123 controls. Fifty-four percent of cases (n = 424) and 53% of controls (n = 1127) had received BCG during childhood (OR: 1.03; 95% CI: 0.89–1.21), while 12% of cases (n = 114) and 11% of controls (n = 235) had received two or more BCG doses (OR: 1.14; 95% CI: 0.88–1.46). After adjusting for age, sex, material deprivation, recruiting hospital and occupation there was no evidence of protection conferred by BCG against SARS-CoV-2 (AOR: 1.01; 95% CI: 0.84–1.21). Among cases, 77 (8.4%) needed hospitalization and 18 (2.0%) died. The vaccinated were as likely as the unvaccinated to require hospitalization (AOR: 1.01, 95% CI: 0.62–1.67) or to die (AOR: 0.85, 95% CI: 0.32–2.39).

Conclusions

BCG does not provide long-term protection against symptomatic COVID-19 or severe forms of the disease.

Mortality in Escherichia coli bloodstream infections: a multinational population-based cohort study

Background

Escherichia coli is the most common cause of bloodstream infections (BSIs) and mortality is an important aspect of burden of disease. Using a multinational population-based cohort of E. coli BSIs, our objectives were to evaluate 30-day case fatality risk and mortality rate, and determine factors associated with each.

Methods

During 2014–2018, we identified 30-day deaths from all incident E. coli BSIs from surveillance nationally in Finland, and regionally in Sweden (Skaraborg) and Canada (Calgary, Sherbrooke, western interior). We used a multivariable logistic regression model to estimate factors associated with 30-day case fatality risk. The explanatory variables considered for inclusion were year (2014–2018), region (five areas), age (< 70-years-old, ≥70-years-old), sex (female, male), third-generation cephalosporin (3GC) resistance (susceptible, resistant), and location of onset (community-onset, hospital-onset). The European Union 28-country 2018 population was used to directly age and sex standardize mortality rates. We used a multivariable Poisson model to estimate factors associated with mortality rate, and year, region, age and sex were considered for inclusion.

Results

From 38.7 million person-years of surveillance, we identified 2961 30-day deaths in 30,923 incident E. coli BSIs. The overall 30-day case fatality risk was 9.6% (2961/30923). Calgary, Skaraborg, and western interior had significantly increased odds of 30-day mortality compared to Finland. Hospital-onset and 3GC-resistant E. coli BSIs had significantly increased odds of mortality compared to community-onset and 3GC-susceptible. The significant association between age and odds of mortality varied with sex, and contrasts were used to interpret this interaction relationship. The overall standardized 30-day mortality rate was 8.5 deaths/100,000 person-years. Sherbrooke had a significantly lower 30-day mortality rate compared to Finland. Patients that were either ≥70-years-old or male both experienced significantly higher mortality rates than those < 70-years-old or female.

Conclusions

In our study populations, region, age, and sex were significantly associated with both 30-day case fatality risk and mortality rate. Additionally, 3GC resistance and location of onset were significantly associated with 30-day case fatality risk. Escherichia coli BSIs caused a considerable burden of disease from 30-day mortality. When analyzing population-based mortality data, it is important to explore mortality through two lenses, mortality rate and case fatality risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06326-x.

Clinical impact of accepting or rejecting a recommendation from a clinical decision support system-assisted antibiotic stewardship program

BACKGROUND

Outcomes associated with physician responses to recommendations from an antimicrobial stewardship program (ASP) at an individual patient level have not yet been assessed. We aimed to compare clinical characteristics and mortality risk among patients for whom recommendations from an ASP were accepted or refused.

METHODS

A prospective cohort study was performed with hospitalized adults who received intravenous or oral antimicrobials at a 677-bed academic centre in Canada in 2014-2017. We included patients with an alert produced by a clinical decision support system (CDSS) for whom a recommendation was made by the pharmacist to the attending physician. The outcome was 90-day in-hospital all-cause mortality.

RESULTS

We identified 3,197 recommendations throughout the study period, of which 2,885 (90.2%) were accepted. The median length of antimicrobial treatment was significantly shorter when a recommendation was accepted (0.26 versus 1.78 d; p < 0.001). Refusal of a recommendation was not associated with mortality (odds ratio 1.32; 95% confidence interval, 0.93 to 1.89; p = 0.12). The independent risk factors associated with in-hospital mortality were age, Charlson Comorbidity Index score, admission to a critical care unit, duration between admission and recommendation, and issuance of a recommendation on a carbapenem.

CONCLUSIONS

The duration of antimicrobial treatment was significantly shorter when a recommendation originating from a CDSS-assisted ASP program was accepted. Future prospective studies including potential residual confounding variables, such as the source of infection or physiological derangement, might help in understanding whether CDSS-assisted ASP will have a direct impact on patient mortality.

Is Antimicrobial Dosing Adjustment Associated with Better Outcomes in Patients with Severe Obesity and Bloodstream Infections? An Exploratory Study

The impact of adjusted treatment on clinical outcomes in patients with severe obesity is unclear. This study included adults with severe obesity admitted for bloodstream infections between 2005 and 2015. The patients were grouped according to the percentage of the appropriateness of the dosage of their antimicrobial treatment: 80–100% = good, 20–79% = moderate, and 0–19% = poor. The association between antimicrobial adjustment and a composite of unfavourable outcomes [intensive care unit stay ≥72 h, duration of sepsis >3 days, length of stay ≥7 days or all-cause 30-day mortality] was assessed using logistic regression. Of 110 included episodes, the adjustment was rated good in 47 (43%) episodes, moderate in 31 (28%), and poor in 32 (29%). Older age, Pitt bacteremia score ≥2, sepsis on day 1, and infection site were independent risk factors for unfavourable outcomes. The level of appropriateness was not associated with unfavourable outcomes. The number of antimicrobials, consultation with an infectious disease specialist, blood urea nitrogen 7–10.9 mmol/L, and hemodialysis were significantly associated with adjusted antimicrobial dosing. While the severity of the infection had a substantial impact on the measured outcomes, we did not find an association between dosing optimization and better outcomes.

The Impact of Prior Season Vaccination on Subsequent Influenza Vaccine Effectiveness to Prevent Influenza-related Hospitalizations Over 4 Influenza Seasons in Canada

BACKGROUND

Recent studies have demonstrated the possibility of negative associations between prior influenza vaccines and subsequent influenza vaccine effectiveness (VE), depending on season and strain. We investigated this association over 4 consecutive influenza seasons (2011-2012 through 2014-2015) in Canada.

METHODS

Using a matched test-negative design, laboratory-confirmed influenza cases and matched test-negative controls admitted to hospitals were enrolled. Patients were stratified into 4 groups according to influenza vaccine history (not vaccinated current and prior season [referent], vaccinated prior season only, vaccinated current season only, and vaccinated both current and prior season). Conditional logistic regression was used to estimate VE; prior vaccine impact was assessed each season for overall effect and effect stratified by age (<65 years, ≥65 years) and type/subtype (A/H1N1, A/H3N2, influenza B).

RESULTS

Overall, mainly nonsignificant associations were observed. Trends of nonsignificant decreased VE among patients repeatedly vaccinated in both prior and current season relative to the current season only were observed in the A/H3N2-dominant seasons of 2012-2013 and 2014-2015. Conversely, in 2011-2012, during which B viruses circulated, and in 2013-2014, when A/H1N1 circulated, being vaccinated in both seasons tended to result in a high VE in the current season against the dominant circulating subtype.

CONCLUSIONS

Prior vaccine impact on subsequent VE among Canadian inpatients was mainly nonsignificant. Even in circumstances where we observed a trend of negative impact, being repeatedly vaccinated was still more effective than not receiving the current season's vaccine. These findings favor continuation of annual influenza vaccination recommendations, particularly in older adults.

CLINICAL TRIALS REGISTRATION

NCT01517191.

2017/18 and 2018/19 seasonal influenza vaccine safety surveillance, Canadian National Vaccine Safety (CANVAS) Network

Background

The Canadian National Vaccine Safety (CANVAS) network monitors the safety of seasonal influenza vaccines in Canada.

Aim

To provide enhanced surveillance for seasonal influenza and pandemic influenza vaccines.

Methods

In 2017/18 and 2018/19 influenza seasons, adults (≥ 15 years of age) and parents of children vaccinated with the seasonal influenza vaccine participated in an observational study using web-based active surveillance. Participants completed an online survey for health events occurring in the first 7 days after vaccination. Participants who received the influenza vaccine in the previous season, but had not yet been vaccinated for the current season, were unvaccinated controls.

Results

In 2017/18, 43,751 participants and in 2018/19, 47,798 completed the online safety survey. In total, 957 of 30,173 participants vaccinated in 2017/18 (3.2%; 95% confidence interval (CI): 3.0–3.4) and 857 of 25,799 participants vaccinated in 2018/19 (3.3%; 95% CI: 3.1–3.5) reported a health problem of sufficient intensity to prevent their normal daily activities and/or cause them to seek medical care (including hospitalisation). This compared to 323 of 13,578 (2.4%; 95% CI: 2.1–2.6) and 544 of 21,999 (2.5%; 95% CI: 2.3–2.7) controls in each respective season. The event rate in vaccinated adults and children was higher than the background rate and was associated with specific influenza vaccines. The higher rate of events was associated with systemic symptoms and migraines/headaches.

Conclusion

In 2017/18 and 2018/19, higher rates of events were reported following seasonal influenza vaccination than in the pre-vaccination period. This signal was associated with several seasonal influenza vaccine products.

Anosmia and dysgeusia associated with SARS-CoV-2 infection: an age-matched case-control study

BACKGROUND

Anosmia and dysgeusia have been reported as potential symptoms of coronavirus disease 2019. This study aimed to confirm whether anosmia and dysgeusia are specific symptoms among those who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

We conducted an age-matched case-control study in the Eastern Townships region of Quebec between Mar. 10 and Mar. 23, 2020. We included adults (age ≥ 18 yr) who tested positive for SARS-CoV-2 by reverse transcription polymerase chain reaction. Cases were matched (1:1) according to 5-year age groups with control patents selected randomly from among all patients who tested negative for SARS-CoV-2 during the same period. Demographic and laboratory information was collected from medical records. Clinical symptoms and comorbidities associated with anosmia and dysgeusia were obtained by telephone interview with a standardized questionnaire.

RESULTS

Among 2883 people tested for SARS-CoV-2, we identified 134 positive cases (70 women [52.2%] and 64 men [47.8%]; median age 57.1 [interquartile range 41.2-64.5] yr). The symptoms independently associated with SARS-CoV-2 positivity in conditional logistic regression were anosmia or dysgeusia or both (adjusted odds ratio [OR] 62.9, 95% confidence interval [CI] 11.0-359.7), presence of myalgia (adjusted OR 7.6, 95% CI 1.9-29.9), blurred vision (adjusted OR 0.1, 95% CI 0.0-0.8) and chest pain (adjusted OR 0.1, 95% CI 0.0-0.6).

INTERPRETATION

We found a strong association between olfactory and gustatory symptoms and SARS-CoV-2 positivity. These symptoms should be considered as common and distinctive features of SARS-CoV-2 infection and should serve as an indication for testing and possible retesting of people whose first test result is negative.

Age-stratified burden of pneumococcal community acquired pneumonia in hospitalised Canadian adults from 2010 to 2015

BACKGROUND

In Canada, 13-valent pneumococcal conjugate vaccine (PCV13) is recommended in childhood, in individuals at high risk of invasive pneumococcal disease (IPD) and in healthy adults aged ≥65 years for protection against vaccine-type IPD and pneumococcal community-acquired pneumonia (pCAP). Since vaccine recommendations in Canada include both age-based and risk-based guidance, this study aimed to describe the burden of vaccine-preventable pCAP in hospitalised adults by age.

METHODS

Surveillance for community-acquired pneumonia (CAP) in hospitalised adults was performed prospectively from 2010 to 2015. CAP was radiologically confirmed, and pCAP was identified using blood and sputum culture and urine antigen testing. Patient demographics and outcomes were stratified by age (16-49, 50-64, ≥65 and ≥50 years).

RESULTS

Of 6666/8802 CAP cases tested, 830 (12.5%) had pCAP, and 418 (6.3%) were attributed to a PCV13 serotype. Of PCV13 pCAP, 41% and 74% were in adults aged ≥65 and ≥50 years, respectively. Compared with non-pCAP controls, pCAP cases aged ≥50 years were more likely to be admitted to intensive care units (ICUs) and to require mechanical ventilation. Older adults with pCAP were less likely to be admitted to ICU or required mechanical ventilation, given their higher mortality and goals of care. Of pCAP deaths, 67% and 90% were in the ≥65 and ≥50 age cohorts, respectively.

CONCLUSIONS

Adults hospitalised with pCAP in the age cohort of 50-64 years contribute significantly to the burden of illness, suggesting that an age-based recommendation for adults aged ≥50 years should be considered in order to optimise the impact of pneumococcal vaccination programmes in Canada.

Validation of the Seegene RV15 multiplex PCR for the detection of influenza A subtypes and influenza B lineages during national influenza surveillance in hospitalized adults

Background. The Serious Outcomes Surveillance Network of the Canadian Immunization Research Network (CIRN SOS) has been performing active influenza surveillance since 2009 (ClinicalTrials.gov identifier: NCT01517191). Influenza A and B viruses are identified and characterized using real-time reverse-transcriptase polymerase chain reaction (RT-PCR), and multiplex testing has been performed on a subset of patients to identify other respiratory virus aetiologies. Since both methods can identify influenza A and B, a direct comparison was performed.Methods. Validated real-time RT-PCRs from the World Health Organization (WHO) to identify influenza A and B viruses, characterize influenza A viruses into the H1N1 or H3N2 subtypes and describe influenza B viruses belonging to the Yamagata or Victoria lineages. In a subset of patients, the Seeplex RV15 One-Step ACE Detection assay (RV15) kit was also used for the detection of other respiratory viruses.Results. In total, 1111 nasopharyngeal swabs were tested by RV15 and real-time RT-PCRs for influenza A and B identification and characterization. For influenza A, RV15 showed 98.0 % sensitivity, 100 % specificity and 99.7 % accuracy. The performance characteristics of RV15 were similar for influenza A subtypes H1N1 and H3N2. For influenza B, RV15 had 99.2 % sensitivity, 100 % specificity and 99.8 % accuracy, with similar assay performance being shown for both the Yamagata and Victoria lineages.Conclusions. Overall, the detection of circulating subtypes of influenza A and lineages of influenza B by RV15 was similar to detection by real-time RT-PCR. Multiplex testing with RV15 allows for a more comprehensive respiratory virus surveillance in hospitalized adults, without significantly compromising the reliability of influenza A or B virus detection.

1135. The 2018 Global Point Prevalence Survey of Antimicrobial Consumption and Resistance: Pediatric Results from 26 Canadian Hospitals

Background

Inappropriate antimicrobial use (AMU) is strongly associated with antimicrobial resistance. The Global Point Prevalence Survey (Global-PPS) is a standardized tool that is used worldwide to characterize inpatient AMU. We report pediatric results from 26 Canadian hospitals that participated in the Global-PPS in 2018.

Methods

The survey was completed by each site on the Global-PPS website for all patients aged 0–17 years hospitalized in a neonatal or pediatric ward on a chosen day between January and December 2018. Data collected included ward type, demographics, antimicrobials prescribed, diagnosis, type of indication (community-acquired [CA] vs. healthcare-associated [HA]) and type of therapy (empiric vs. targeted). Quality indicators included guideline compliance, medical record documentation of diagnosis, antimicrobial stop/review date, and surgical prophylaxis (SP) duration.

Results

Of the 26 sites, 23 were mixed and 3 were pediatric hospitals, with data on 767 inpatients. Overall, 25.8% (n = 198) of patients received at least one antimicrobial, and 21.9% (n = 168) were on at least one antibiotic. The highest AMU was found in Hematology-Oncology (84%), Pediatric Intensive Care (55.3%) and surgical (42.1%) units. Of the 330 antimicrobial prescriptions, 40.9% were for CA infections, 23% for medical prophylaxis, 20% for HA infections and 2.7% for SP. The most commonly treated infections were sepsis (16%) and lower respiratory tract infection (12.1%). The top five prescribed antibiotics were aminopenicillins (20.4%), aminoglycosides (16.1%), third-generation cephalosporins (15.4%), piperacillin–tazobactam (7.5%) and trimethoprim-sulfamethoxazole (7.5%). Diagnosis and stop/review date were documented for 88.1% and 65.1% of prescriptions, respectively. Compliance to local guidelines was found in 91.5% of therapies. SP exceeded 24 hours in 88.9% of courses.

Conclusion

The Global-PPS generated Canada-wide data on inpatient pediatric AMU, which will allow hospitals to benchmark and develop local quality improvement interventions to enhance appropriate AMU. Targets for improvement include suboptimal antimicrobial stop/review date documentation and prolonged SP.

Disclosures

All authors: No reported disclosures.

2715. Pneumococcal Community-Acquired Pneumonia Attributed to PCV13 Serotypes in Hospitalized Adults: Comparison of the 50–64 and 65+ Age Groups

Background

Methods

Results

Conclusion

Disclosures

462. Prospective Surveillance of Invasive Group A Streptococcal Infections in Toronto, Ontario, Canada: 1992–2017

Background. Background

Invasive Group A streptococcal (iGAS) infections remain a substantial source of morbidity and mortality. We explore the clinical and molecular epidemiology of iGAS infections in Toronto, Ontario, Canada over a 26-year period.

Methods

The Toronto Invasive Bacterial Diseases Network has performed population-based surveillance for iGAS infections in metropolitan Toronto and Peel regions since 1992. Participating microbiology laboratories report and submit sterile site specimens for central processing. M typing was performed on iGAS isolates until September 2006; thereafter emm typing was performed. Clinical information was collected by chart review using standardized collection forms.

Results

Over the 26-year period there were 2819 iGAS infections, representing an average incidence of 2.85 per 100,000 residents with a nadir of 1.65 in 1993 and a peak of 4.52 in 2014. Nosocomial infections occurred in 8.9% (251/2,819). There was substantial variation in annual incidence rates over the study period with increases from 1992 until 2002 and then 2004 until 2014 (analysis for trend, P < 0.001). Skin and soft-tissue infections were the most common clinical presentation, accounting for 33.2% (936/2,819), followed by bacteremia without a focus in 15.4% (435/2,819). Necrotizing fasciitis was observed in 7.4% (208/2,819) and criteria for toxic shock syndrome were met in 17.6% (497/2,819). Overall case fatality within 30 days of hospitalization was 15.3% (95% confidence interval 14.0 to 16.6) and did not change over time. M serotype distribution varied yearly with the most common type being M1 at 22.2% (626/2,189) followed by M12 at 8.2% (230/2,189), then M89 at 5.8% (163/2,189). Antibiotic susceptibility was available from 1998 onwards with overall clindamycin susceptibility at 92.3% (1,957/2,121) and erythromycin susceptibility at 87.9% (1864/2,121).

Conclusion

The incidence of iGAS in Toronto, Ontario has varied over time, with no recent increase apparent. Similar to worldwide observations, M1 serotype was the most commonly isolated; most common serotypes demonstrated cyclical variation. Case fatality rates have remained relatively constant making the development of a vaccine imperative.

Disclosures

All authors: No reported disclosures.

2714. Streptococcus pneumoniae Nasopharyngeal Carriage in Canadian Adults Hospitalized with Community-Acquired Pneumonia from 2010 to 2017

Background

Streptococcus pneumoniae can colonizes the human nasopharynx, and can cause life-threatening infections like community-acquired pneumonia (CAP) and invasive pneumococcal diseases (IPD). In Canada, the 13-valent conjugate vaccine (PCV13) was introduced in childhood immunization since 2010, with hopes that it would not only protect the vaccinated, but also confer indirect protection to adults through herd immunity. Given data on S. pneumoniae nasopharyngeal (NP) carriage in adults is scarce, this study reports on S. pneumoniae-positivity and serotype distribution in adult carriage from years 2010 to 2017.

Methods

Active surveillance was performed in adults hospitalized with for CAP or IPD from December 2010 to 2017. For assessment of S. pneumoniae carriage, NP swabs were tested using lytA and cpsA real-time PCR. S. pneumoniae-positive NPs were subjected to serotyping using conventional and real-time multiplex PCRs.

Results

Overall, 6472 NP swabs were tested, and Spn was identified in 366 (5.7%). Of the 366 S. pneumoniae-positive NP swabs, a serotype was assigned in 355 (97.0%). From years 2010 to 2017, the proportion of S. pneumoniae-positive NP swabs declined from 8.9% to 4.3%. This was also reflected in the proportion of serotypeable results attributed to PCV13 serotypes, which also declined from 76.9% to 42.2%. The decline was primarily attributed to PCV13 serotypes 7F and 19A. PCV13 serotype 3 remained predominant throughout the study, as did non-PCV13 serotypes like 22F, 33F, and 11A. On the other hand, a proportional rise over time was noted for non-vaccine serotypes (from 15.4% to 31.1%). This was primarily attributed to serotypes 23A, 15A, and 35B.

Conclusion

Monitoring serotype trends is important to assess the impact of pneumococcal vaccines. While herd immunity from PCV13 childhood immunization was anticipated, few studies have assessed its impact on adult carriage. This study described Spn serotype distribution in adults over years 2010 to 2017, demonstrating not only a reduction of PCV13 serotypes over time, but a proportional rise in non-vaccine serotypes. These emerging serotypes may represent the emergence of serotype replacement. Ongoing serotype surveillance will be needed to compare S. pneumoniae carriage to serotypes associated with pneumococcal CAP and IPD.

Disclosures

All authors: No reported disclosures.

Effectiveness of Influenza Vaccination on Hospitalizations and Risk Factors for Severe Outcomes in Hospitalized Patients With COPD

BACKGROUND

The effectiveness of influenza vaccination in reducing influenza-related hospitalizations among patients with COPD is not well described, and influenza vaccination uptake remains suboptimal.

METHODS

Data were analyzed from a national, prospective, multicenter cohort study including patients with COPD, hospitalized with any acute respiratory illness or exacerbation between 2011 and 2015. All patients underwent nasopharyngeal swab screening with polymerase chain reaction (PCR) testing for influenza. The primary outcome was an influenza-related hospitalization. We identified influenza-positive cases and negative control subjects and used multivariable logistic regression with a standard test-negative design to estimate the vaccine effectiveness for preventing influenza-related hospitalizations.

RESULTS

Among 4,755 hospitalized patients with COPD, 4,198 (88.3%) patients with known vaccination status were analyzed. The adjusted analysis showed a 38% reduction in influenza-related hospitalizations in vaccinated vs unvaccinated individuals. Influenza-positive patients (n = 1,833 [38.5%]) experienced higher crude mortality (9.7% vs 7.9%; P = .047) and critical illness (17.2% vs 12.1%; P < .001) compared with influenza-negative patients. Risk factors for mortality in influenza-positive patients included age > 75 years (OR, 3.7 [95% CI, 0.4-30.3]), cardiac comorbidity (OR, 2.0 [95% CI, 1.3-3.2]), residence in long-term care (OR, 2.6 [95% CI, 1.5-4.5]), and home oxygen use (OR, 2.9 [95% CI, 1.6-5.1]).

CONCLUSIONS

Influenza vaccination significantly reduced influenza-related hospitalization among patients with COPD. Initiatives to increase vaccination uptake and early use of antiviral agents among patients with COPD could reduce influenza-related hospitalization and critical illness and improve health-care costs in this vulnerable population.

TRIAL REGISTRY

ClinicalTrials.govNo.:NCT01517191; URL www.clinicaltrials.gov.

992. 2016–2017 Influenza Burden of Disease and End-of-Season Influenza Vaccine Effectiveness (VE) Estimates for Preventing Influenza-Related Hospitalization Among Canadian Adults: An Analysis From the Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Network

Background

To inform public health decision making around influenza prevention and treatment, ongoing surveillance of the influenza burden of disease and assessment of influenza vaccine effectiveness (VE) is critical. The Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Network conducts active surveillance each influenza season to characterize the burden of influenza disease and to provide estimates of influenza VE to prevent influenza-related hospitalization in Canadian adults (≥16 years of age).

Methods

Active surveillance for influenza was conducted at 13 hospitals in four provinces beginning on November 15, 2016 and ending April 30, 2017. Patients admitted with any respiratory diagnosis or symptom were eligible for enrolment. Eligible patients had a nasopharyngeal swab collected and tested for influenza using polymerase chain reaction (PCR). Patients who tested positive for influenza were considered cases; patients who tested negative for influenza were eligible to become matched controls. Detailed demographic and medical information were obtained from the medical record. Influenza VE was estimated as 1 − odds ratio (OR) of influenza in vaccinated vs. unvaccinated patients × 100% using conditional logistic regression, with corresponding 95% confidence intervals (CIs).

Results

A total of 1,431 influenza cases were enrolled; the majority were influenza A (n = 1,299) and 100% of patients with known influenza A subtype were A/H3N2. Among all influenza cases, 144 (10.1%) patients were admitted to the intensive care unit (ICU) and 91 (6.4%) patients died within 30 days of discharge. Overall adjusted influenza VE for prevention of influenza-related hospitalization in all ages was 23.3% (95% CI: 2.9–39.4%), with slightly lower VE observed in patients ≥65 years (VE: 19.4%; 95% CI: −7.8–39.8%) and higher VE observed in patients <65 years (VE: 47.9%; 95% CI: 9.9–69.9%).

Conclusion

Overall, influenza VE was low but effective (VE: 23%) for preventing influenza-related hospitalization during the 2016–2017 season in Canada. Given the low influenza VE observed, continued assessment of influenza VE is crucial to inform immunization policy in Canada and to emphasize the importance of the development and utilization of improved influenza vaccines.

Disclosures

M. K. Andrew, GSK: Grant Investigator, Research grant. Pfizer: Grant Investigator, Research grant. sanofi pasteur: Grant Investigator, Research grant. T. F. Hatchette, GSK: Grant Investigator, Research grant. Pfizer: Grant Investigator, Research grant. Abbvie: Consultant, Speaker honorarium. J. McElhaney, GSK: Scientific Advisor, Speaker honorarium. sanofi pasteur: Scientific Advisor, Speaker honorarium. A. McGeer, GSK: Grant Investigator, Research grant. Hoffman La Roche: Grant Investigator, Research grant. sanofi pasteur: Grant Investigator, Research grant. A. Poirier, sanofi pasteur: Investigator, Research grant. Actelion: Grant Investigator, Research grant. J. Powis, GSK: Grant Investigator, Research grant. Merck: Grant Investigator, Research grant. Roche: Grant Investigator, Research grant. Synthetic Biologics: Investigator, Grant recipient. M. Semret, GSK: Grant Investigator, Research grant. Pfizer: Grant Investigator, Research grant. S. Trottier, CIHR: Grant Investigator, Research grant. S. A. McNeil, GSK: Grant Investigator, Research grant. Pfizer: Grant Investigator, Research grant. Merck: Collaborator and Consultant, Contract clinical trials and Speaker honorarium. Novartis: Collaborator, Contract clinical trials. sanofi pasteur: Collaborator, Contract clinical trials.

1468. PCV13 Serotype Trends Over Time in Pneumococcal Community Acquired Pneumonia: Which Method(s) Work Best?

Background

Recent studies have shown that a 13-valent pneumococcal conjugate vaccine (PCV13) was effective at preventing vaccine-type pneumococcal community acquired pneumonia (CAP_Spn) in healthy adults. With the anticipated herd immunity from routine infant immunization with PCV13 used since 2010, the benefits of adult immunization in Canada were unclear and surveillance for CAP_Spn with serotype distributions was needed. This study aimed to compare PCV13 serotype trends in CAP_Spn from 2010 to 2015 using various laboratory methods.

Methods

Active surveillance for CAP was performed from 2010 to 2015 in adult hospitals across five Canadian provinces. Bacteremic CAP_Spn cases were identified using blood culture, and nonbacteremic CAP_Spn cases by sputum culture or using a PCV13-specific urine antigen detection (UAD_PCV13). Serotype was assigned using Quellung reaction, PCR, or UAD_PCV13. CAP_Spn cases were categorized by laboratory test(s), age, or disease (bacteremic or nonbacteremic CAP_Spn).

Results

A diagnostic test for S. pneumoniae was performed on 6,687 CAP cases. S. pneumoniae positivity decreased from 2011 to 2014, and increased again in 2015. PCV13 serotypes followed a similar trend, where the decline in PCV13 serotypes attributed to serotypes 7F and 19A was noted, and the proportion of serotype 3 increased over time. Similar trends were seen regardless of whether data were categorized by laboratory test(s), age, or disease.

Conclusion

Our data suggest that all methods showed similar trends in PCV13 serotype distribution over 2010 to 2015. Herd immunity through childhood immunization with PCV13 was evident, but insufficient to afford complete protection to hospitalized adults. CAP_Spn remained a significant cause of morbidity and mortality in hospitalized adult, and serotype 3 seems to be persisting despite herd immunity seen with other serotypes. Ongoing surveillance is required.

Disclosures

T. Hatchette, GSK: Grant Investigator, Research grant; Pfizer: Grant Investigator, Research grant; Abbvie: Consultant, Speaker honorarium. M. K. Andrew, GSK: Grant Investigator, Research grant; Pfizer: Grant Investigator, Research grant; Sanofi Pasteur: Grant Investigator, Research grant. A. McGeer, GSK: Grant Investigator, Research grant; Hoffman La Roche: Grant Investigator, Research grant; Sanofi Pasteur: Grant Investigator, Research grant. M. Semret, GSK: Grant Investigator, Research grant; Pfizer: Grant Investigator, Research grant. S. Trottier, CIHR: Grant Investigator, Research grant. S. A. McNeil, GSK: Grant Investigator, Research grant; Pfizer: Grant Investigator, Research grant; Merck: Collaborator and Consultant, Contract clinical trials and Speaker honorarium; Novartis: Collaborator, Contract clinical trials; Sanofi Pasteur: Collaborator, Contract clinical trials.

Secular trends in incidence of invasive beta-hemolytic streptococci and efficacy of adjunctive therapy in Quebec, Canada, 1996-2016

Objectives

To examine secular changes in the incidence of invasive beta-hemolytic streptococcal infections, and to assess the efficacy of immunoglobulins and clindamycin as adjunctive therapies in the management of Streptococcus pyogenes infections.

Methods

Retrospective cohort study of all cases of invasive group A (GAS), B (GBS), C or G (GCGS) streptococcal infections managed in a Canadian tertiary center from 1996–2016. Population incidence was measured for diabetics and non-diabetics. Adjusted odds ratios (AOR) and their 95% confidence intervals (CI) were calculated by logistic regression.

Results

741 cases were identified (GAS: 249; GBS: 304; GCGS: 188). While the incidence of invasive GAS infections fluctuated with no clear trend, incidence of invasive GBS and GCGS increased over time and were 8.4 and 6.3 times higher in diabetics. Mortality of invasive GAS infections decreased from 16% (6/37) in 1996–2001 to 4% (4/97) in 2011–15. Among patients with GAS infections, clindamycin administered concomitantly with a beta-lactam within 24 hours of admission decreased mortality (AOR: 0.04, 95%CI: 0.003–0.55, P = 0.02. Immunoglobulins had no such effect (AOR: 1.66, 95%CI: 0.16–17.36, P = 0.67). The protective effect of clindamycin was similar in patients with pneumonia/empyema compared to all others.

Conclusion

Incidence of GBS and GCGS infections increased due to an expansion of the high-risk population (elderly diabetics), but also rose in non-diabetics. No such secular change was seen for invasive GAS infections. The decrease in mortality in patients with invasive GAS infections presumably reflects better case-management. Adjunctive clindamycin reduced mortality in invasive GAS infections; immunoglobulins did not, but power was limited. The highest mortality was seen in patients with GAS pneumonia/empyema, for whom clindamycin was protective but underused.

A postpartum vaccination promotion intervention using motivational interviewing techniques improves short-term vaccine coverage: PromoVac study

BACKGROUND

Due to the increasing number of vaccine-hesitant parents, new effective immunization promotion strategies need to be developed to improve the vaccine coverage (VC) of infants. This study aimed to assess the impact of an educational strategy of vaccination promotion based on motivational interviewing (MI) techniques targeting parents and delivered at the maternity ward, for the VC of infants at 3, 5, and 7 months of age.

METHODS

An individual educational information session, administered using MI techniques, regarding immunization of infants aged 2, 4, and 6 months was (experimental group) or was not (control group) proposed to parents during the postpartum stay at the maternity ward. Immunization data were obtained through the Eastern Townships Public Health registry for infants at 3, 5, and 7 months of age. Absolute VC increases at 3, 5, and 7 months in the experimental group were calculated and the relative risks with the respective 95% confidence intervals were computed using univariate logistic regression with the generalized estimating equations (GEE) procedure. Multivariate regression using GEE was used to adjust for confounding variables.

RESULTS

In the experimental and control groups, 1140 and 1249 newborns were included, respectively. A significant increase in VC of 3.2, 4.9, and 7.3% was observed at 3, 5, and 7 months of age (P < 0.05), respectively. The adjusted relative risk of the intervention's impact on vaccination status at 7 months of age was 1.08 (95% confidence interval: 1.03-1.14) (P = 0.002).

CONCLUSIONS

An educational strategy using MI techniques delivered at the maternity ward may be effective in increasing VC of infants at ages 3, 5, and 7 months. MI could be an effective tool to overcome vaccine hesitancy.

Influenza vaccine effectiveness to prevent influenza-related hospitalizations and serious outcomes in Canadian adults over the 2011/12 through 2013/14 influenza seasons: A pooled analysis from the Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS Network)

BACKGROUND

Ongoing assessment of influenza vaccine effectiveness (VE) is critical to inform public health policy. This study aimed to determine the VE of trivalent influenza vaccine (TIV) for preventing influenza-related hospitalizations and other serious outcomes over three consecutive influenza seasons.

METHODS

The Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN) conducted active surveillance for influenza in adults ≥16 years (y) of age during the 2011/2012, 2012/2013 and 2013/2014 seasons in hospitals across Canada. A test-negative design was employed: cases were polymerase chain reaction (PCR)-positive for influenza; controls were PCR-negative for influenza and were matched to cases by date, admission site, and age (≥65 y or <65 y). All cases and controls had demographic and clinical characteristics (including influenza immunization status) obtained from the medical record. VE was estimated as 1-OR (odds ratio) in vaccinated vs. unvaccinated patients × 100%. The primary outcome was VE of TIV for preventing laboratory-confirmed influenza-related hospitalization; secondary outcomes included VE of TIV for preventing influenza-related intensive care unit (ICU) admission/mechanical ventilation, and influenza-related death.

RESULTS

Overall, 3394 cases and 4560 controls were enrolled; 2078 (61.2%) cases and 2939 (64.5%) controls were ≥65 y. Overall matched, adjusted VE was 41.7% (95% Confidence Interval (CI): 34.4-48.3%); corresponding VE in adults ≥65 y was 39.3% (95% CI: 29.4-47.8%) and 48.0% (95% CI: 37.5-56.7%) in adults <65 y, respectively. VE for preventing influenza-related ICU admission/mechanical ventilation in all ages was 54.1% (95% CI: 39.8-65.0%); in adults ≥65 y, VE for preventing influenza-related death was 74.5% (95% CI: 44.0-88.4%).

CONCLUSIONS

While effectiveness of TIV to prevent serious outcomes varies year to year, we demonstrate a statistically significant and clinically important TIV VE for preventing hospitalization and other serious outcomes over three seasons. Public health messaging should highlight the overall benefit of influenza vaccines over time while acknowledging year to year variability. ClinicalTrials.gov Identifier: NCT01517191.

Resource utilization and cost of influenza requiring hospitalization in Canadian adults: A study from the serious outcomes surveillance network of the Canadian Immunization Research Network

BACKGROUND

Consideration of cost determinants is crucial to inform delivery of public vaccination programs.

OBJECTIVES

To estimate the average total cost of laboratory-confirmed influenza requiring hospitalization in Canadians prior to, during, and 30 days following discharge. To analyze effects of patient/disease characteristics, treatment, and regional differences in costs.

METHODS

Study utilized previously recorded clinical characteristics, resource use, and outcomes of laboratory-confirmed influenza patients admitted to hospitals in the Serious Outcomes Surveillance (SOS), Canadian Immunization Research Network (CIRN), from 2010/11 to 2012/13. Unit costs including hospital overheads were linked to inpatient/outpatient resource utilization before and after admissions.

RESULTS

Dataset included 2943 adult admissions to 17 SOS Network hospitals and 24 Toronto Invasive Bacterial Disease Network hospitals. Mean age was 69.5 years. Average hospital stay was 10.8 days (95% CI: 10.3, 11.3), general ward stays were 9.4 days (95% CI: 9.0, 9.8), and ICU stays were 9.8 days (95% CI: 8.6, 11.1) for the 14% of patients admitted to the ICU. Average cost per case was $14 612 CAD (95% CI: $13 852, $15 372) including $133 (95% CI: $116, $150) for medical care prior to admission, $14 031 (95% CI: $13 295, $14 768) during initial hospital stay, $447 (95% CI: $271, $624) post-discharge, including readmission within 30 days.

CONCLUSION

The cost of laboratory-confirmed influenza was higher than previous estimates, driven mostly by length of stay and analyzing only laboratory-confirmed influenza cases. The true per-patient cost of influenza-related hospitalization has been underestimated, and prevention programs should be evaluated in this context.

Replacing an Inpatient Electronic Medical Record

Objective: Since it is important to develop strategies for the successful implementation of electronic clinical information systems, the aim of this study is to explore where, and to what extent, users’ attitudes toward the former system that is being replaced may vary.

Methods: A cross-sectional survey of 346 nurses and physicians practicing in two Canadian teaching hospitals resulted in a total response rate of 63%. User attitudes were measured in three dimensions: a) user satisfaction with the system’s quality attributes, b) perceived system usefulness, and c) perceived impact on quality of care and patient safety. The current system (the one being replaced) was analyzed as a dual system composed of both paper-based and electronic records.

Results: The results on user satisfaction demonstrate a wide variation in opinions, with satisfaction ranging from 4.2 to 7.7 on a 10-point disagree-agree, Likert scale. The quality attributes varied by record type, with differences that were systematically in favor of the electronic record component, which received higher scores. The results also highlighted large differences by user group. Physicians and nurses systematically rated the two record formats differently. The nurses were more satisfied with the attributes of the paper-based record. Multivariate regression analyses results also revealed strong interdependencies among the three dimensions of user attitudes, to the extent that perceived system usefulness was strongly correlated with system quality attributes and the system outcomes were also correlated, although less strongly, with the two former system dimensions.

Conclusion: Understanding users’ attitudes toward a clinical information system in use, both in its paper and electronic aspects, is crucial for developing more successful implementation strategies for electronic record systems.

Influenza vaccine effectiveness against influenza-related hospitalization during a season with mixed outbreaks of four influenza viruses: a test-negative case-control study in adults in Canada

BACKGROUND

The Serious Outcomes Surveillance (SOS) Network was established to monitor seasonal influenza complications among hospitalized Canadian adults and to assess the effectiveness of influenza vaccination against severe outcomes. Here we report age- and strain-specific vaccine effectiveness (VE) in preventing severe outcomes during a season characterized by mixed outbreaks of four different influenza strains.

METHODS

This prospective, multicentre, test-negative case-control study evaluated the VE of trivalent influenza vaccine (TIV) in the prevention of laboratory-confirmed influenza-hospitalization in adults aged ≥16 years (all adults) and adults aged 16-64 years (younger adults). The SOS Network identified hospitalized patients with diagnoses potentially attributable to influenza during the 2011/12 influenza season. Swabs collected at admission were tested by reverse transcriptase polymerase chain reaction (RT PCR) or viral culture to discriminate influenza cases (positive) from controls (negative). VE was calculated as 1-odds ratio (OR) of vaccination in cases versus controls × 100.

RESULTS

Overall, in all adults, the unadjusted and adjusted VEs of TIV against influenza-hospitalization were 41.8% (95% Confidence Interval [CI]: 26.0, 54.3), and 42.8% (95% CI: 23.8, 57.0), respectively. In younger adults (16-64 years), the unadjusted and adjusted VEs of TIV against influenza-hospitalization were 35.8% (95% CI: 4.5, 56.8) and 33.2% (95% CI: -6.7, 58.2), respectively. In the all adults group, adjusted VE against influenza A/H1N1 was 72.5% (95% CI: 30.5, 89.1), against A/H3N2 was 86.1% (95% CI: 40.1, 96.8), against B/Victoria was 40.5% (95% CI: -28.9, 72.6), and against B/Yamagata was 32.3% (95% CI: -8.3, 57.7). The adjusted estimate of early season VE (from November 1 to March 11) was 54.4% (95% CI: 29.7-70.4), which was higher than late season (from March 11 to May 25) VE estimate (VE: 29.7%, 95% CI: -5.3, 53.1).

CONCLUSIONS

These results suggest that TIV was highly effective against A viruses and moderately effective against B viruses during a mild season characterised by co-circulation of four influenza strains in Canada. Findings underscore the need to provide VE assessment by subtype/lineage as well as the timing of vaccination (early season vs late season) to accurately evaluate vaccine performance and thus guide public health decision-making.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01517191. Registration was retrospective and the date of registration was January 17, 2012.

Bezlotoxumab for the prevention of Clostridium difficile recurrence

Clostridium difficile infection is a major economic and clinical burden, due to its high frequency of recurrence. Currently recommended treatments are not efficient for prevention and may contribute to the risk of recurrent infection. In recent years, research has focused on strategies to lessen this risk. Bezlotoxumab is a monoclonal antibody that prevents recurrences of C. difficile infection through the antagonism of toxin B. Areas covered: In this review, the authors discuss the burden of C. difficile infection and its recurrences, the mechanisms underlying the recurrences, and current C. difficile treatments. They subsequently analyze the strategic therapeutic rationale for bezlotoxumab use, as well as the supporting clinical evidence. Expert opinion: Bezlotoxumab is an attractive solution for reducing the unacceptable level of recurrence that occurs with the currently recommended C. difficile treatments and other alternative therapies under consideration. Even though bezlotoxumab has not been tested in large-scale trials exclusively in cases of already established recurrent C.difficile infection (rCDI), it has an advantage over current treatments in that it does not interfere with the patient's gut flora while directly neutralizing the key virulence factor. Although cost remains an important factor against its widespread use, simpler administration, fewer side-effects, and better social acceptability justify its consideration for treating rCDI.

Sustained impact of a computer-assisted antimicrobial stewardship intervention on antimicrobial use and length of stay

Objectives

: Prospective audit and feedback interventions are the core components of an antimicrobial stewardship programme. Herein, we describe the sustained impact of an antimicrobial stewardship programme, based on a novel clinical decision-support system (Antimicrobial Prescription Surveillance System; APSS), on antimicrobial use and costs, hospital length of stay (LOS) in days and the proportion of inappropriate antimicrobial prescriptions.

Methods

A quasi-experimental, retrospective study was conducted using interrupted time series between 2008 and 2013. Data on all hospitalized adults receiving antimicrobials were extracted from the data warehouse of a 677 bed academic centre. The intervention started in August 2010. Prospective audit and feedback interventions, led by a pharmacist, were triggered by APSS based on deviations from published and local guidelines. Changes in outcomes before and after the intervention were compared using segmented regression analysis.

Results

APSS reviewed 40 605 hospitalizations for 35 778 patients who received antimicrobials. The intervention was associated with a decrease in the average LOS (level change -0.92, P  < 0.01; trend -0.08, P  < 0.01; intercept 11.4 days), antimicrobial consumption in DDDs/1000 inpatient days (level change -32.4, P  < 0.01; trend -1.12, P  <   0.02; intercept 243 DDDs per 1000 days of hospitalization), antimicrobial spending in Canadian dollars (level change -19 649, P  = 0.01; trend -1881, P  < 0.01; intercept $74 683) and proportion of non-concordance with local guidelines for prescribing antimicrobials (level change -2.3, P  = 0.04; intercept 41%).

Conclusions

The implementation of the APSS-initiated strategy was associated with a positive impact on antimicrobial use and spending, LOS and inappropriate prescriptions. The high rate of accepted interventions may have contributed to these results.

External validation of clinical scores to predict complications of Clostridium difficile infection

Background

Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea. About one in 5 patients with CDI (median 18%) develop a complication (cCDI), including mortality. Many predictive scores have been published to identify patients at risk of cCDI but none is currently recommended for clinical use and few were validated. We conducted an external validation study of predictive tools for cCDI.

Methods

Predictive tools were identified through a systematic review. We included those reporting at least an internal validation process. We performed the external validation on a multicenter prospective cohort of 1380 Canadian adults with confirmed CDI. Most cases were elderly (median age 71), had a healthcare facility-associated CDI (90%), and cCDI occurred in 8%. NAP1 strain was found in 52%. The performance of each scoring system was analyzed using individual outcomes. Modifications in predictors were made to match available data in the validation cohort.

Results

We assessed 3 predictive scores and one predictive model. The performance (95% CI) of higher thresholds are shown in the Table. All scores had a low sensitivity and PPV, and moderate specificity and NPV. The model of Shivashankar 2013 (age, WBC> 15, narcotic use, antacids use, creatinine ratio > 1.5) predicted 25% probability of cCDI. All showed similar AUC (0.63–0.67).

Conclusion

The predictive tools included in our study showed moderate performance in a validation cohort with a low rate of cCDI and high proportion of NAP1 strains. Further research is needed to develop an accurate predictive tool to guide clinicians in the management of CDI.

Disclosures

J. Powis, Merck: Grant Investigator, Research grant; GSK: Grant Investigator, Research grant; Roche: Grant Investigator, Research grant; Synthetic Biologicals: Investigator, Research grant

Epidemiology of Influenza Viruses in Canada over the 2011–2012 to 2013–2014 Seasons: A Study from the Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN)

Background

Influenza virus activity varies seasonally and within season. Epidemiology of serious influenza outcomes is contingent on the prevalent circulating strain/s and susceptible age group/s. Given the strain variability over the 2011–2012 through 2013–2014 seasons in Canada, this study examined the clinical and epidemiological profiles of different influenza strains causing adult hospitalizations.

Methods

During these three influenza seasons, the Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN) enrolled adults hospitalized with acute respiratory illness across Canada. Nasopharyngeal swabs (NPs) from influenza cases were tested for strain characterization using real-time reverse transcriptase polymerase chain reaction (rtRT-PCR). A primary assay differentiated A and B influenza viruses. Subsequently, influenza A viruses were subtyped as H1N1 or H3N2, and influenza B lineages were differentiated as Victoria or Yamagata. Laboratory results were compared with patient demographic data and clinical outcomes.

Results

Over three consecutive influenza seasons, 3394 cases of hospitalized acute respiratory illness were laboratory-confirmed as influenza. At 72.4%, influenza A was predominant across all seasons, while influenza B caused 27.6%. Most of the influenza A cases were due to H3N2 (58.7%), while H1N1 accounted for 41.3%. For influenza B, the Yamagata lineage was predominant at 88.4% whereas the Victoria lineage accounted for 11.6%. Outcome analyses are presented for each influenza A subtype and influenza B lineage, overall and per season. Considering serious outcomes in patients ≥65, higher proportions of patients hospitalized with the H1N1 strain experienced intensive care unit (ICU) admission and need for mechanical ventilation, while higher proportions of patients hospitalized with B/Yamagata and H3N2 died within 30 days of admission.

Conclusion

Comprehensive collection of surveillance data paired with NP specimens by the CIRN SOS Network was conducive to broader understanding of influenza strain activity and associated outcomes at the subtype and lineage level. This data is important to make informed recommendations for the use of multicomponent influenza vaccines.

Disclosures

M. Elsherif, Canadian Institutes of Health Research: Investigator, Research grant. Public Health Agency of Canada: Investigator, Research grant. GSK: Investigator, Research grant. T. Hatchette, GSK: Grant Investigator, Grant recipient; Pfizer: Grant Investigator, Grant recipient. Abbvie: Speaker for a talk on biologics and risk of TB reactivation, Speaker honorarium.M. K. Andrew, GSK: Grant Investigator, Research grant. Pfizer: Grant Investigator, Research grant. Sanofi-Pasteur: Grant Investigator, Research grant. J. McElhaney, GSK Vaccines: Scientific Advisor, Speaker honorarium. A. Mcgeer, Hoffman La Roche: Investigator, Research grant. GSK: Investigator, Research grant. sanofi pasteur: Investigator, Research grant. J. Powis, Merck: Grant Investigator, Research grant. GSK: Grant Investigator, Research grant. Roche: Grant Investigator, Research grant. Synthetic Biologicals: Investigator, Research grant. M. Semret, GSK: Investigator, Research grant. Pfizer: Investigator, Research grant. S. Trottier, Canadian Institutes of Health Research: Investigator, Research grant. L. Valiquette, GSK: Investigator, Research grant. S. McNeil, GSK: Contract Clinical Trials and Grant Investigator, Research grant. Merck: Contract Clinical Trials and Speaker’s Bureau, Speaker honorarium. Novartis: Contract Clinical Trials, No personal renumeration. sanofi pasteur: Contract Clinical Trials, No personal renumeration

Derivation and Validation of a Clinical Prediction Rule for Complications of Clostridium difficile Infection Using a Multicenter Prospective Cohort

Background

Clostridium difficileinfection (CDI) outbreaks were associated with increase in unfavorable outcomes. Identifying and predicting risk of developing complications (cCDI) early in the course of illness could improve clinical decision-making. We developed and validated a prediction rule for cCDI.

Methods

Adult inpatients with confirmed CDI in 10 Canadian hospitals were enrolled and followed for 90 days. Data within 48h of CDI diagnosis were collected: demographics, underlying illnesses, past medical and drug history, clinical signs, blood tests, and strain ribotype. cCDI was defined as one or more of: colonic perforation, toxic megacolon, colectomy, need of vasopressors, ICU admission due to CDI, or if CDI contributed to 30-day death. Predictors’ selection was supported by experts’ opinion suggesting 17 clinical criteria. Cross-validation technique was used (2:1 ratio) and multivariable logistic regression for predictive modeling in the derivation subset. The optimal model was assessed by area under ROC curve (AUC) and prediction error (PE). A predictive score was built by assigning points proportional to adjusted risk estimates.

Results

Among 1380 patients enrolled, 1050 were used for predictive modeling (median age 70 years and one-third infected by ribotype 027 strains). Cases were split into training (n = 700) and validation sets (n = 350). A cCDI occured in 8% and 6.6% respectively. The optimal model with a PE of 5% and an AUC of 0.84 in the validation set included WCC (< 4, 12–19.9, or ≥20 × 10⁹/L), BUN≥11 mmol/L, serum albumin <25 g/L, heart rate > 90/minute, and respiratory rate >20/minute. A predictive score of min 0 and max 13 points was derived. A score ≥7 points was associated with 70% cases of cCDI, showed 68% sensitivity (95% CI, 55–80) in the derivation set and 70% (51–88) in the validation set, a specificity of 73% (69–76) and 76% (72–81) respectively, 17% PPV (9–25), and 97% NPV (95–99) in both sets.

Conclusion

Using a large multicenter prospective cohort and robust modeling approach, we derived a predictive score that included easily available measures at the bedside. The score showed acceptable performance. Further validation is needed on cohorts with different characterstics (non-outbreak setting, higher rate of cCDI). Other approaches such as combination of biomarkers could be more predictive of cCDI.

Disclosures

J. Powis, Merck: Grant Investigator, Research grant; GSK: Grant Investigator, Research grant; Roche: Grant Investigator, Research grant; Synthetic Biologicals: Investigator, Research grant

External validation of predictive scores for mortality following Clostridium difficile infection

Background

The burden of Clostridium difficile infection (CDI) has increased in the last decade, with more adverse outcomes and related mortality. Although many predictive scores were developed, few were validated and their performances were sub-optimal. We conducted an external validation study of predictive scores or models for mortality in CDI.

Methods

Published predictive tools were identified through a systematic review. We included those reporting at least an internal validation approach. A multicenter prospective cohort of 1380 adults with confirmed CDI enrolled in two Canadian provinces was used for external validation. Most cases were elderly (median age 71), had a healthcare facility-associated CDI (90%), and 52% were infected by NAP1/BI/027 strains. All-cause 30-day death occurred in 12% of patients. The performance of each scoring system was analyzed using individual primary outcomes.

Results

We identified two scores which performances (95% CI) are shown in the table. Both had low sensitivity and PPV, moderate specificity and NPV, and similar AUC/ROC (0.66 vs. 0.77 in the derivation cohort, and 0.69 vs. 0.75 respectively). One predictive model for 30 days all-cause mortality (Archbald-Pannone 2015, including Charlson score, WBC, BUN, diagnosis in ICU, and delirium*) was associated with only 5% increase in odds of death (crude OR = 1.05 (1.03–1.06)) with an AUC of 0.74 (0.7–0.8).

Conclusion

The predictive models of CDI mortality evaluated in our study have limitations in their methods and showed moderate performances in a validation cohort consisting of a majority of CDI caused by NAP1 strains. An accurate predictive tool is needed to guide clinicians in the management of CDI to prevent adverse outcomes.

Disclosures

J. Powis, Merck: Grant Investigator, Research grant; GSK: Grant Investigator, Research grant; Roche: Grant Investigator, Research grant; Synthetic Biologicals: Investigator, Research grant

Impact of Antivirals in the Prevention of Serious Outcomes Associated with Influenza in Hospitalized Canadian Adults: A Pooled Analysis from the Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN)

Background

Antiviral treatment of influenza in outpatient settings is associated with modest improvement in outcomes but benefit in inpatient settings remains unclear. We assessed the impact of antiviral treatment on the severe outcomes death and intensive care unit (ICU) admission and/or need for mechanical ventilation (MV) in hospitalized influenza patients.

Methods

Patients admitted to hospitals of the CIRN SOS Network with an acute respiratory illness from 2011/12–2013/14 who tested polymerase chain reaction (PCR) positive for influenza were included. Demographic and medical information were obtained from patient interview or the medical chart. Main outcomes of interest were ICU admission and/or need for MV, and death. Logistic regression with backwards stepwise selection was used to estimate odds ratios (ORs) and 95% confidence limits (CIs) for the association between antiviral use and severe outcomes overall, and stratified by time from symptom onset to antiviral start (&lt;48hours, 48hours &lt;5 days, 5–21 days).

Results

Over 3 influenza seasons, 4,679 patients were enrolled; 59% were aged ≥65 years, 52% were female, and 89% had a comorbidity. Influenza vaccination status was available for 4,019 (86%) patients, of whom 1,796 (45%) had received current season vaccine. Of 4,679 patients, 16% of patients were admitted to ICU and/or required MV and 9% died. Overall, 54% of hospitalized influenza patients received an antiviral; mean time from the onset of symptoms to antiviral start was 4.28 days (range: 0–21 days). Treatment with antivirals was associated with a significant reduction in admission to ICU and/or need for MV (OR = 0.10; 95% CI: 0.08–0.13; P &lt; 0.001), but was not significantly associated with a reduction in death (P = 0.454) irrespective of time between symptom onset and start of antivirals.

Conclusion

In this study, treatment with antivirals in hospitalized patients with influenza was associated with a significant reduction in ICU admission and MV, even when initiated a mean of 4.28 days from symptom onset. Reduction in death was not demonstrated. These findings support current recommendations for antiviral use in hospitalized adults and suggest increased compliance with these guidelines may reduce morbidity and cost.

Disclosures

M. K. Andrew, GSK: Grant Investigator, Research grant; Pfizer: Grant Investigator, Research grant; Sanofi-Pasteur: Grant Investigator, Research grant; A. Chit, Sanofi pasteur: Employee, Salary; G. Dos Santos, GSK: Employee, Salary; Business and Decision Life Sciences (Contractor for GSK Vaccines): Independent Contractor, Salary; M. Elsherif, Canadian Institutes of Health Research: Investigator, Research grant; Public Health Agency of Canada: Investigator, Research grant; GSK: Investigator, Research grant; F. Haguinet, GSK: Employee, Salary; S. A. Halperin, GSK: Scientific Advisor, Consulting fee; GSK: Grant Investigator, Research grant; T. Hatchette, GSK: Grant Investigator, Grant recipient; Pfizer: Grant Investigator, Grant recipient; Abbvie: Speaker for a talk on biologics and risk of TB reactivation, Speaker honorarium; B. Ibarguchi, GSK: Employee, Salary; J. M. Langley, GSK: Investigator, Research grant; Canadian Institutes of Health Research: Investigator, Research grant; J. Mcelhaney, GSK: Scientific Advisor, Honorarium to institution; Sanofi pasteur: Scientific Advisor, Honorarium to institution; A. Mcgeer, Hoffman La Roche: Investigator, Research grant; GSK: Investigator, Research grant; Sanofi pasteur: Investigator, Research grant; J. Powis, Merck: Grant Investigator, Research grant; GSK: Grant Investigator, Research grant; Roche: Grant Investigator, Research grant; Synthetic Biologicals: Investigator, Research grant; M. Semret, GSK: Investigator, Research grant; Pfizer: Investigator, Research grant; V. Shinde, Novavax: Employee, Salary; GSK: Shareholder, Stocks; GSK: Employee, Salary; S. Trottier, Canadian Institutes of Health Research: Investigator, Research grant; L. Valiquette, GSK: Investigator, Research grant; S. McNeil, GSK: Contract Clinical Trials and Grant Investigator, Research grant; Merck: Contract Clinical Trials and Speaker’s Bureau, Speaker honorarium; Novartis: Contract Clinical Trials, No personal renumeration; Sanofi pasteur: Contract Clinical Trials, No personal renumeration

The Importance of Frailty in the Assessment of Influenza Vaccine Effectiveness Against Influenza-Related Hospitalization in Elderly People

Background

Influenza is an important cause of morbidity and mortality among older adults. Even so, effectiveness of influenza vaccine for older adults has been reported to be lower than for younger adults, and the impact of frailty on vaccine effectiveness (VE) and outcomes is uncertain. We aimed to study VE against influenza hospitalization in older adults, focusing on the impact of frailty.

Methods

We report VE of trivalent influenza vaccine (TIV) in people ≥65 years of age hospitalized during the 2011-2012 influenza season using a multicenter, prospective, test-negative case-control design. A validated frailty index (FI) was used to measure frailty.

Results

Three hundred twenty cases and 564 controls (mean age, 80.6 and 78.7 years, respectively) were enrolled. Cases had higher baseline frailty than controls (P = .006). In the fully adjusted model, VE against influenza hospitalization was 58.0% (95% confidence interval [CI], 34.2%-73.2%). The contribution of frailty was important; adjusting for frailty alone yielded a VE estimate of 58.7% (95% CI, 36.2%-73.2%). VE was 77.6% among nonfrail older adults and declined as frailty increased.

Conclusions

Despite commonly held views that VE is poor in older adults, we found that TIV provided good protection against influenza hospitalization in older adults who were not frail, though VE diminished as frailty increased.

Clinical Trials Registration

NCT01517191.

Burden of vaccine-preventable pneumococcal disease in hospitalized adults: A Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) network study

BACKGROUND

Pneumococcal community acquired pneumonia (CAP_Spn) and invasive pneumococcal disease (IPD) cause significant morbidity and mortality worldwide. Although childhood immunization programs have reduced the overall burden of pneumococcal disease, there is insufficient data in Canada to inform immunization policy in immunocompetent adults. This study aimed to describe clinical outcomes of pneumococcal disease in hospitalized Canadian adults, and determine the proportion of cases caused by vaccine-preventable serotypes.

METHODS

Active surveillance for CAP_Spn and IPD in hospitalized adults was performed in hospitals across five Canadian provinces from December 2010 to 2013. CAP_Spn were identified using sputum culture, blood culture, a commercial pan-pneumococcal urine antigen detection (UAD), or a serotype-specific UAD. The serotype distribution was characterized using Quellung reaction, and PCR-based serotyping on cultured isolates, or using a 13-valent pneumococcal conjugate vaccine (PCV13) serotype-specific UAD assay.

RESULTS AND CONCLUSIONS

In total, 4769 all-cause CAP cases and 81 cases of IPD (non-CAP) were identified. Of the 4769 all-cause CAP cases, a laboratory test for S. pneumoniae was performed in 3851, identifying 14.3% as CAP_Spn. Of CAP cases among whom all four diagnostic test were performed, S. pneumoniae was identified in 23.2% (144/621). CAP_Spn cases increased with age and the disease burden of illness was evident in terms of requirement for mechanical ventilation, intensive care unit admission, and 30-day mortality. Of serotypeable CAP_Spn or IPD results, predominance for serotypes 3, 7F, 19A, and 22F was observed. The proportion of hospitalized CAP cases caused by a PCV13-type S. pneumoniae ranged between 7.0% and 14.8% among cases with at least one test for S. pneumoniae performed or in whom all four diagnostic tests were performed, respectively. Overall, vaccine-preventable pneumococcal CAP and IPD were shown to be significant causes of morbidity and mortality in hospitalized Canadian adults in the three years following infant PCV13 immunization programs in Canada.