Publications by authors named "Demczuk W"

In the province of Alberta, Canada, invasive disease caused by serogroup 20 (serotypes 20A/20B) has been increasing in incidence. Here, we characterize provincial invasive serogroup 20 isolates collected from 1993 to 2019 alongside invasive and non-invasive serogroup 20 isolates from the Global Pneumococcal Sequencing (GPS) Project collected from 1998 to 2015. Trends in clinical metadata and geographic location were evaluated, and serogroup 20 isolate genomes were subjected to molecular sequence typing, virulence and antimicrobial resistance factor mining, phylogenetic analysis and pangenome calculation.

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Streptococcus pneumoniae serotype 19A is a highly diverse, often antimicrobial-resistant Gram-positive bacterium which can cause invasive pneumococcal disease (IPD). In 2021, public health authorities in the Canadian province of Québec observed an increase of serotype 19A IPD in children <5 years. The purpose of this study was to determine the clonal composition of serotype 19A isolates collected from this age group in Québec, from 2016 to 2021.

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  • The IRIS Consortium investigated the impact of the COVID-19 pandemic on invasive diseases caused by specific bacteria over a four-year period, comparing data from before and during the pandemic.
  • Laboratories from 30 countries provided surveillance data, revealing a significant decrease in cases of Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis during the pandemic, while Streptococcus agalactiae cases remained unchanged.
  • An estimated 36,289 cases of invasive bacterial disease were prevented due to COVID-19 containment measures during the first two years of the pandemic.
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  • The study tracks invasive pneumococcal disease (IPD) isolates in Canada from 2011 to 2020 to evaluate how well different pneumococcal vaccines (PCV10, PCV13, PCV15, PCV20, and PPSV23) cover these strains under evolving antibiotic and vaccine pressures.
  • Researchers analyzed over 14,000 isolates, finding that PCV20 provided the most extensive coverage, protecting against a higher percentage of serotypes compared to PCV13 and PCV15, particularly among various demographics and resistance profiles.
  • The results suggest that higher-valency vaccines like PCV20 are more effective in addressing the diversity of IPD isolates, although there was no
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  • This study aims to analyze the genetic backgrounds and resistance traits of common pneumococcal serotypes in Canada over the past five years, focusing on their behavior after the introduction of the PCV13 vaccine.
  • Researchers sequenced the genomes of a sample from the ten most prevalent serotypes and used this data to identify important characteristics, including virulence and antimicrobial resistance (AMR) genes.
  • The results revealed significant changes in the prevalence of certain serotypes, with some increasing in numbers and one, 19A, decreasing, highlighting the need for ongoing surveillance to track new bacterial lineages and AMR development in Canada.
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Objectives: To investigate the levels of MDR in the predominant serotypes of invasive Streptococcus pneumoniae isolated in Canada over a 10 year period.

Methods: All isolates were serotyped and had antimicrobial susceptibility testing performed, in accordance with CLSI guidelines (M07-11 Ed., 2018).

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Objectives: To assess the antimicrobial susceptibility of 14 138 invasive Streptococcus pneumoniae isolates collected in Canada from 2011 to 2020.

Methods: Antimicrobial susceptibility testing was performed using the CLSI M07 broth microdilution reference method. MICs were interpreted using 2022 CLSI M100 breakpoints.

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Invasive Group B Streptococcus (GBS) can infect pregnant women, neonates, and older adults. Invasive GBS serotype VIII is infrequent in Alberta; however, cases have increased in recent years. Here, genomic analysis was used to characterize fourteen adult invasive serotype VIII isolates from 2009 to 2021.

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Bloodstream infections are a major cause of morbidity and mortality worldwide. Early administration of appropriate antimicrobial therapy can improve patient survival and prevent antimicrobial resistance (AMR). Whole genome sequencing (WGS) can provide information for pathogen identification, AMR prediction and sequence typing earlier than current phenotypic diagnostic methods.

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Background: Invasive pneumococcal disease (IPD), which is caused by , has been a nationally notifiable disease in Canada since 2000. The use of conjugate vaccines has markedly decreased the incidence of IPD in Canada; however, the distribution of serotypes has shifted in favour of non-vaccine types. This report summarizes the demographics, serotypes and antimicrobial resistance of IPD infections in Canada in 2020.

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  • In 2020, the incidence of invasive group A streptococcal disease (iGAS) in Canada increased to 8.1 cases per 100,000 population after a slight drop from previous years, indicating an ongoing public health issue.
  • The study analyzed 2,867 iGAS isolates, revealing a shift in prevalent types; types 49 and 76 have risen in prevalence, while type 1 has decreased significantly.
  • Antimicrobial resistance rates were noted, with 11.5% resistant to erythromycin and lower resistance to clindamycin and chloramphenicol, highlighting challenges in treatment options.
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Group A (GAS) is a rare cause of peritonitis with only a few reports of disease associated with surgical abortion, vaginal delivery, or intrauterine devices, most of which are speculated to be in association with the female genital tract. Only a single case of GAS infection transmission through contemporary oral sex has been previously reported. We report a strange case of GAS peritonitis occurring after abortion and oral sex.

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  • This study examines data on pneumococcal pneumonia and invasive disease in Canadian hospitalized adults from 2010 to 2017, highlighting the importance of active surveillance for understanding disease trends.
  • It finds that adults aged 65 and older are significantly affected by both bacteremic and non-bacteremic community-acquired pneumonia (pCAP), with a notable decline in certain serotypes from 2010 to 2014, followed by a plateau from 2015 to 2017.
  • The study concludes that monitoring both types of pCAP is crucial, especially as current vaccination strategies show insufficient herd protection, necessitating further attention to vaccination efforts in adults.
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Objectives: To compare the proportion of invasive and respiratory tract isolates of Streptococcus pneumoniae, including MDR and XDR strains, that demonstrated PCV-15 and PPSV-23 serotypes in Canada from 2007 to 2020.

Methods: The CANWARD study collected 2984 S. pneumoniae isolates from 2007 to 2020 (1054 invasive, 1930 respiratory).

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Background: Invasive pneumococcal disease due to Streptococcus pneumoniae can cause mortality and severe morbidity due to sepsis, meningitis and pneumonia, particularly in young children and the elderly. Recurrent invasive pneumococcal disease is rare yet serious sequelae of invasive pneumococcal disease that is associated with the immunocompromised and leads to a high mortality rate.

Method: This retrospective study reviewed recurrent invasive pneumococcal disease cases from the Canadian Immunization Monitoring Program, ACTive (IMPACT) between 1991 and 2019, an active network for surveillance of vaccine-preventable diseases and adverse events following immunization for children ages 0-16 years.

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Azithromycin-resistant (AZIR) gonorrhea has been steadily increasing in Canada over the past decade, which is cause for alarm, as azithromycin (AZI) has been part of the combination therapy recommended by the Canadian Guidelines on Sexually Transmitted Infections (CGSTI) since 2012. Neisseria gonorrhoeae with AZI MICs ≥1 mg/L collected between 2015 and 2018 as part of the Gonococcal Antimicrobial Surveillance Program-Canada underwent antimicrobial susceptibility testing, molecular typing, and whole-genome sequencing. Regional, demographic, and clinical isolation site comparisons were made to aid in our understanding of AZI susceptibility trending.

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  • The ICS program monitors five invasive bacterial diseases in northern Canada, which have a higher prevalence compared to the rest of the country.
  • Data from 1999 to 2018 revealed significant differences in incidence rates, with Indigenous residents facing higher rates of IPD, iGAS, and Hi compared to non-Indigenous populations.
  • Overall, these diseases pose a serious health risk, particularly for Indigenous peoples, children, and seniors in northern regions.
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Antimicrobial resistance in Streptococcus pneumoniae represents a threat to public health, and monitoring the dissemination of resistant strains is essential to guiding health policy. Multiple-variable linear regression modeling was used to determine the contributions of molecular antimicrobial resistance determinants to antimicrobial MICs for penicillin, ceftriaxone, erythromycin, clarithromycin, clindamycin, levofloxacin, and trimethoprim-sulfamethoxazole. Training data sets consisting of Canadian S.

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  • The pneumococci population in Canada is changing due to antibiotic and vaccine use, with a new 15-valent pneumococcal conjugate vaccine undergoing trials that includes serotypes 22F and 33F.
  • The study analyzed 597 Streptococcus pneumoniae isolates from Canadian hospitals before and after the introduction of the PCV-13 vaccine using whole genome sequencing to track genetic changes and resistance patterns.
  • Findings indicate a rise in resistant clones of both serotype 22F and 33F since the PCV-13 rollout, suggesting that while some serotypes have largely declined, others have persisted or even increased in prevalence, indicating ongoing challenges for pneumococcal disease management.
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A 15-valent conjugate vaccine that provides protection against Streptococcus pneumoniae serotypes 22F and 33F is in development. Here we report on the prevalence, antimicrobial susceptibility, and clonal structure of these serotypes in Canada. From 2011 to 2018, the SAVE study collected 11,044 invasive S.

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After the introduction of pneumococcal conjugate vaccines for children, invasive pneumococcal disease caused by Streptococcus pneumoniae serotype 4 declined in all ages in Alberta, Canada, but it has reemerged and spread in adults in Calgary, primarily among persons who are experiencing homelessness or who use illicit drugs. We conducted clinical and molecular analyses to examine the cases and isolates. Whole-genome sequencing analysis indicated relatively high genetic variability of serotype 4 isolates.

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Background: Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis, which are typically transmitted via respiratory droplets, are leading causes of invasive diseases, including bacteraemic pneumonia and meningitis, and of secondary infections subsequent to post-viral respiratory disease. The aim of this study was to investigate the incidence of invasive disease due to these pathogens during the early months of the COVID-19 pandemic.

Methods: In this prospective analysis of surveillance data, laboratories in 26 countries and territories across six continents submitted data on cases of invasive disease due to S pneumoniae, H influenzae, and N meningitidis from Jan 1, 2018, to May, 31, 2020, as part of the Invasive Respiratory Infection Surveillance (IRIS) Initiative.

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Article Synopsis
  • A study assessed the effectiveness of pneumococcal conjugate vaccines (PCV-10 and PCV-13) against invasive Streptococcus pneumoniae in Canada from 2011 to 2017, analyzing 9,166 isolates.
  • The study found a significant decrease in the prevalence of serotypes covered by both vaccines over time, with PCV-13 showing better coverage overall compared to PCV-10.
  • Particularly, PCV-13 was more effective against multidrug-resistant strains, covering 53.3% of these isolates versus 14.6% for PCV-10, highlighting its superiority in combating resistant infections.
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The emergence of strains with resistance (R) to extended-spectrum cephalosporins (ESCs) represents a public health threat of untreatable gonococcal infections. This study was designed to determine the prevalence and molecular mechanisms of ESC of Shanghai isolates. A total of 366 isolates were collected in 2017 in Shanghai.

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Background: Since December 2016, the basic military training (BMT) facility for the Canadian Armed Forces (CAF) has experienced repeated outbreaks of Group A (GAS). In 2018, a voluntary mass antibiotic prophylaxis (MAP) program was implemented to interrupt GAS transmission among recruits. The objective of this study was to describe the epidemiology of three GAS outbreaks and a period of increased pharyngitis infections at the CAF BMT facility in Québec over a two-year span, and to detail the prevention and control measures implemented to mitigate the risk to recruit health.

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