The rapidity and aggressiveness of many group A streptococcal ( Streptococcus pyogenes ) clinical syndromes highlight the urgent need for a vaccine. Two related combination cryptic epitope peptide vaccines, J8-CRM+K4S2-CRM (‘J8-K4S2’) and p*17-CRM+K4S2-CRM (‘p*17-K4S2’), are novel vaccine candidates under investigation. In this single-centred, two-stage, unblinded sentinel safety dosing, then randomized, double-blinded, placebo-controlled trial, 30 volunteers were recruited (NCT04882514). Ten volunteers (Stage 1) were given test doses of J8-K4S2 and then p*17-K4S2 in a staggered, unblinded fashion at weeks 0, 3 and 6 to confirm immediate safety of the products. This was followed by twenty volunteers (Stage 2) who were randomized to receive either of the trial vaccines, J8-K4S2 or p*17-K4S2, or comparator (RabAvert) vaccine following the same vaccination schedule. The primary outcome was vaccine safety; the secondary outcome was immunogenicity. Both vaccine candidates were well tolerated and elicited robust immune responses. The most common adverse events noted were transient injection site pain, injection site erythema, fatigue and headache. These were similar for those receiving either the novel vaccines or the rabies vaccine comparator. There were no high-grade attributable adverse events and no severe adverse events overall. Immunogenicity assessment by ELISA demonstrated that both vaccine candidates consistently induced strong and sustained antibody responses against their respective target antigens, J8 and p*17, with lower responses to K4S2 commensurate with the lower dose of K4S2 present in the vaccines. Both vaccines induced antibody responses to the surface of different strains of live S. pyogenes . All 20 participants who received the candidate vaccines achieved at least a 4-fold rise in J8- or p*17-specific antibody titers from baseline, demonstrating 100% seroconversion, while 90% also seroconverted to K4S2. Notably, these elevated antibody responses persisted for at least six months post-vaccination, remaining significantly above pre-immunisation levels, highlighting the durability of the immune response induced by both vaccines. The safety and immunogenicity profiles for J8-K4S2 and p*17-K4S2 were favourable and support ongoing development of these promising vaccine candidates.

BackgroundDespite decades of study, the characteristics of infants with invasive group B streptococcus (GBS) late onset disease (LOD) (onset day 7-89 of life) and in particular very late onset disease (VLOD) (after day 89 of life) are not well described.Materials and methodsThis was a retrospective cohort study of infants hospitalized in four Edmonton hospitals April 1, 1994 through June 30, 2022 with LOD or VLOD GBS invasive disease. Data were collected on demographics, day of onset of infection, clinical manifestations and outcomes.ResultsThere were 115 episodes of LOD in 111 infants of which 50 infants (45%) were preterm. Onset of initial LOD infection was on median day 27 (IQR 19-40.5) of life. All but one infant was bacteremic while 38/111 (34%) had proven and 17/111 (15%) had possible GBS meningitis. Five of 111 (5%) died before hospital discharge with all deaths probably due to GBS. There were 11 episodes of VLOD in 11 infants (8 [73%] preterm) presenting on median day 116 (IQR 103-138) (range 93-207) of life. Three (27%) had GBS meningitis. All 11 survived to discharge. As compared with infants with LOD, those with VLOD were less likely to be born vaginally (n = 3/11 [27%] versus n = 72/111 [65%] p = 0.036), more likely to be mechanically ventilated during their birth hospitalization (n = 5/11 [45%] versus n = 17/111 [15%]; p = 0.039), and more likely to have serious infection with other pathogens during their GBS admission (n = 3/11 [27%] versus n = 4/111 [4%]); p = 0.032). Serotype III accounted for 78% of LOD and 64% of VLOD cases.ConclusionGBS remains a significant cause of infant morbidity and mortality. Infants with VLOD appear to have more complex medical histories prior to GBS infection than those with LOD. There is increasing evidence that GBS may sometimes be an opportunistic pathogen in infants over 89 days of age. This speaks of the need for increased surveillance for VLOD with further research into its epidemiology and underlying immunologic determinants.

Importance:Invasive pneumococcal disease (IPD) remains a significant burden despite implementation of pneumococcal conjugate vaccines (PCVs) in childhood immunization programs. Objective:To analyze IPD epidemiology in Canada following 7-valent pneumococcal conjugate vaccine (PCV7) and 13-valent PCV (PCV13) introductions and evaluate the potential outcomes associated with newer vaccines, such as PCV15, PCV20, and PCV21. Design, Setting, and Participants:This cross-sectional study included IPD isolates from children and adults with IPD across Canada from January 1, 2000, to December 31, 2019. Cases were identified through bacterial isolates sent to national reference laboratories. Data were analyzed from January 2022 to January 2026. Exposures:Introduction of PCV7 and PCV13. Main Outcomes and Measures:IPD incidence rates and proportion analyses were calculated for serotypes belonging to PCV7, PCV13, PCV15, PCV20, and PCV21 using Statistics Canada population estimates. PCV7 and PCV13 impact was assessed using generalized linear piecewise quasi-Poisson regression models. Results:A total of 37 921 IPD isolates were analyzed. Age data were available for 37 591 isolates (17.9% children aged <18 years; 82.1% adults aged ≥18 years), and sex data for 35 303 isolates (51.5% male; 41.6% female). Following PCV7 introduction, PCV7-specific serotype IPD rates decreased by 98.5%, from an incidence rate (IR) of 20.1 (95% CI, 17.8-22.6) in year 0 to 0.31 (95% CI, 1.0-0.5) in year 7 (P < .001), in children younger than 5 years (direct cohort) and 76.3%, from an IR of 2.2 (95% CI, 1.6-3.0) in year 0 to (0.5; 95% CI, 0.3-0.9) in year 7, in individuals aged 10 years or older (indirect cohort), although the difference was not statistically significant (P = .74). After PCV13 introduction, PCV13-only serotype IPD rates decreased by 90.6% in the direct cohort, from an IR of 10.3 (95% CI, 8.812.1) in year 0 to 1.0 (95% CI, 0.65-1.44) in year 9 (P = .03), and 57.1% in the indirect cohort, from an IR of 3.8 (95% CI, 3.1 to 4.6) in year 0 to 1.6 (95% CI, 1.2 to 2.1) in year 9 (P = .001). Vaccine serotypes 3, 4, and 19F persisted, with increases observed in adults aged 18 to 49 years and 50 to 64 years for serotypes 3 and 4, and in adults aged 65 years and older for serotype 19F. Serotype 19A cases declined after introduction of PCV13, with the highest incidence in adults aged 65 years and older. From 2015 to 2019, the potential serotype coverages by PCV15, PCV20, and PCV21 were estimated at 23% to 29%, 32% to 39%, and 36% to 49%, respectively, while nonvaccine types accounted for 45% to 52%. Conclusions and Relevance:This cross-sectional study of IPD isolates in Canada found that despite initial IPD reductions following PCVs, IPD in Canada increased, driven by emerging nonvaccine types and persistence of some vaccine serotypes. Indirect protection was limited, particularly among older adults, highlighting the need for direct adult vaccination strategies. These findings suggest that while PCV15, PCV20, and PCV21 may improve serotype coverage, continued development of broader-spectrum vaccines is essential to further reduce IPD burden.

Background:Pertussis, a vaccine preventable respiratory illness caused by the bacterium Bordetella pertussis (B. pertussis), has been a nationally reportable disease in Canada for over 100 years; however, cases resurged in Canada and globally in 2023-2024. Objective:To examine the breadth and depth of pertussis strain surveillance currently being carried out across Canada. Methods:A survey was sent to all ten provincial public health laboratories inquiring how pertussis was diagnosed or identified in the laboratory, including the polymerase chain reaction (PCR) diagnostic methods, bacteriological culture, identification and strain characterization such as molecular typing and antibiotic susceptibility testing. Results:Nine of the ten provincial laboratories provided responses. Five provincial laboratories reported performing bacteriological culture, and some only from specimens that tested positive by PCR. Long-term storage of submitted and historical specimens took place in six laboratories. Identification of B. pertussis was commonly done through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis, though immunochemical and PCR-based methods were also used. One laboratory conducted antibiotic susceptibility testing in specific circumstances. No laboratory performed fimbriae serotyping or examined expression of other pertussis vaccine antigens. One laboratory used whole-genome sequencing for outbreak investigation. The PCR diagnostics were performed in eight of the responding laboratories and always include IS481 and pIS1001 gene targets. Some laboratories also reported using other gene targets to identify and distinguish between B. pertussis, B. parapertussis, B. holmesii and B. bronchiseptica. Conclusion:Given the global increase in pertussis, with the emergence of macrolide-resistant and pertactin-deficient strains, strain characterization should be added to the Canadian national pertussis surveillance program.

Background:Invasive pneumococcal disease (IPD), which is caused by Streptococcus pneumoniae, has been a nationally notifiable disease in Canada since 2000. This report summarizes the demographics, serotypes and antimicrobial resistance of IPD isolates collected in Canada in 2023. Methods:The Public Health Agency of Canada's National Microbiology Laboratory (Winnipeg, Manitoba) collaborates with provincial and territorial public health laboratories to conduct national surveillance of IPD. Serotypes and minimum inhibitory concentrations were obtained from whole genome sequencing data. Results:The incidence of IPD in Canada was 10.2 cases per 100,000 population in 2022, increasing from the low rate of 5.6 cases per 100,000 population in 2021. A total of 4,760 IPD isolates were collected during 2023. The most common serotypes overall were 3 (12.3%, n=587), 4 (12.2%, n=580), 22F (8.2%, n=391) and 9V (7.1%, n=340). Serotypes 4 (7.1%-12.2%, p<0.0001) and 9V (1.3%-7.1%, p<0.0001) also increased significantly in prevalence since 2019, resulting in an overall increase in the proportion of PCV15 and PCV20/non-V116 serotypes causing disease. The highest rates of antimicrobial resistance in 2023 were seen with clarithromycin (25.8%), doxycycline (17.5%) and trimethoprim/sulfamethoxazole (15.9%). Multidrug-resistance continued to increase from 2019 to 2023 (8.4%-13.2%, p<0.0001) and rates were highest in serotypes 9V, 15A, 19A, 23A and 35B. Conclusion:The high number of IPD cases collected in 2023 represents a return to pre-SARS-CoV-2 pandemic disease activity. Several serotypes included in previous conjugate vaccine formulations are highly common or are increased in prevalence, including 3, 4 and 9V. Continued surveillance of pneumococcal serotypes is imperative to evaluate vaccine effectiveness, particularly as new vaccine formulations are approved and integrated into immunization schedules in Canada.

Intro: The epidemiology of invasive group A Streptococcus (iGAS) has been previously documented in Alberta, Canada; however, the role coinfections with respiratory viral infections (VRIs) play with associated emm types remains unclear [...]

BACKGROUND:The COVID-19 pandemic caused major disruptions to essential tuberculosis (TB) services globally. We evaluated the performance of the TB program in Alberta, Canada, in 2 periods - before and during the pandemic - to estimate the impact of those disruptions. METHODS:We applied 10 program performance indicators and their related targets and compared them by period. The performance indicators included a measure of decline in the age- and sex-adjusted incidence by population group, the proportion of recently arrived immigrants screened on time, and 5 case management and 3 close contact management indicators. We measured performance targets by time period and clinic type - outpatient versus virtual. We used interrupted time series analysis to estimate the impact of the COVID-19 pandemic response on timeliness of immigrant screening. RESULTS:Since 2009, the rate of disease has declined in the Canadian-born but not the foreign-born population. However, the rate of disease by population group was not different prepandemic versus during the pandemic. Program performance was not negatively affected by the pandemic in general, but there was a large reduction in immigration and, in turn, the number of immigrants referred for screening (37.6%) and contacts identified for assessment (71.8%) during the pandemic, associated with improvements to the proportion of referrals assessed (91.7% v. 96.6%, relative risk [RR] 0.949, 95% confidence interval [CI] 0.936-0.962); contacts assessed (81.7% v. 90.0%, RR 0.908, 95% CI 0.875-0.943), and contacts completing treatment of infection (90.4% v. 97.1%, RR 0.931, 95% CI 0.886-0.979). Among patients with TB disease, monitoring of treatment response was suboptimal, whereas other targets were met or nearly met. Virtual clinic performance tended to be worse during the pandemic than the outpatient clinics. INTERPRETATION:COVID-19-related disruptions were not as substantial in the Alberta TB program as elsewhere, likely because of its centralized operational model and protection of its staff from secondment. However, no progress has been made toward reducing TB incidence. Better resourcing of prevention activity and a more responsive information system should be considered.

Mycobacterium caprae is a causative agent of tuberculosis that affects both humans and animals. Here, we present the draft genome sequences of two M. caprae strains. These genome sequences may improve understanding of M. caprae epidemiology and support diagnostic development.

The high antigenic diversity of Streptococcus pyogenes (StrepA) presents extensive challenges to vaccine development; however, cryptic epitopes—conserved across emm types—offer an alternative approach [...]

Introduction. Invasive meningococcal disease (IMD) is a nationally notifiable illness in Canada due to its potential severity and transmissibility. Vaccination strategies differ by province/territory and are informed by changes in the antigenic characteristics of circulating strains.Gap Statement. Though IMD statistics are tracked at a provincial/territorial level, there is a lack of published data characterizing trends in the epidemiology of this disease at a national level.Aim. To examine the epidemiology of culture-confirmed IMD in Canada during the period of 2015-2023.Methodology. Meningococcal isolates sent to the National Microbiology Laboratory Branch between 2015 and 2023 as part of routine national surveillance were characterized for serogroup by bacterial agglutination and genetic methods. Clonal analysis was done by MLST. Demographic information was derived from requisition forms accompanying the samples.Results. The proportion of IMD caused by serogroup W meningococci (MenW) in 2015-2023 was 30.0% with more (62.9%) MenW cases detected in western provinces. Serogroup B meningococci (MenB) IMD was more common (53.4%) in Quebec and Atlantic Canada. Clonal analysis reveals 168 distinct sequence types between 2015 and 2023, with 103 belonging to MenB. The average age of MenB cases during this time was 29.1 years, significantly younger than serogroup C (MenC) (45.3 years), serogroup Y (MenY) (48.3 years) and MenW (43.0 years) patients. Additionally, 31.5% of MenB and 21.7% of MenC IMD isolates were collected from cerebrospinal fluid (CSF) or brain samples, which were significantly higher than that for MenY (12.2%) and MenW (7.3%) isolates.Conclusions. Results from this and previous studies showed temporal and geographical variations in the serogroups causing IMD in Canada. MenB also showed the most genetic diversity, caused IMD in a significantly younger population and was more often isolated from CSF and brain samples than other serogroups.

ABSTRACT Background Mycobacterium abscessus complex is known to cause life‐threatening disease in lung transplantation (LT) recipients (LTRs). Therefore, many centers consider the presence of M. abscessus as a relative contraindication to LT. Methods We conducted a multicenter retrospective cohort study including all 4 LT centers in Canada. All LTRs transplanted in 2006–2016 with at least one respiratory sample positive for M. abscessus prior or posttransplantation were included. Pulmonary disease was defined using the American Thoracic Society criteria. Minimal follow‐up duration was 5 years after transplantation. Results Among 2181 LTRs across Canada, 14 had M. abscessus disease after LT (incidence rate 1.1/1000 transplant‐years) and 6 had pulmonary colonization (incidence rate 0.5/1000 transplant‐years). Fifteen patients had M. abscessus cultured before LT. Among those with pretransplant M. abscessus , 53% (8/15) developed M. abscessus infection posttransplant (6 disease, 2 colonization). Posttransplant disease was less frequent among those with microbiologic eradication before transplant (0% vs. 85.7%, p = 0.001). LTRs with pretransplant M. abscessus had comparable survival to those without M. abscessus (log rank p = 0.37). Among patients with pretransplant infection, mortality was higher in those who did not achieve microbiological eradication before transplantation (57.1% vs. 0%, p = 0.03) and those who developed disease after transplantation (66.7% vs. 0%, p = 0.01). Conclusions M. abscessus is an uncommon cause of infection among LTRs. Survival among those with pretransplant M. abscessus infection was similar to that observed in noninfected LTRs. However, lack of eradication before transplantation was associated with higher posttransplant disease and mortality.

Background: Tracheostomy bypasses physical barriers that decrease microbial access to the lower airway, which can lead to changes to the lung microbiota. Patients often become chronically colonized with potential pathogens. This study described the incidence and prevalence of specific organisms in a 5-y cohort of children with tracheostomy. Methods: This retrospective cohort of children aged 0-18 y with tracheostomy identified associations between microbial species and subject characteristics including reason for tracheostomy, gastrostomy tube (G-tube), fundoplication, and ventilator use using chi-square test or Fisher exact test. Results: Of 113 eligible patients, 79 (57% male) met study inclusion criteria. Reasons for tracheostomy included airway obstruction secondary to craniofacial anomalies in 16 children (20%), upper-airway obstruction in 14 subjects (17.3%), neuromuscular disorder in 19 subjects (24%), bronchopulmonary dysplasia with or without pulmonary hypertension in 17 subjects (21%), and congenital heart disease in 13 subjects (16%). Most (69%) used a ventilator for at least 6 h/d; 63% had a G-tube; 41% also had a Nissen fundoplication. Of the 20% with upper-airway obstruction, one third were ventilator dependent, unlike other diagnoses where 57% used a ventilator. Staphylococcus aureus (52/113), Pseudomonas aeruginosa (43/113), and Stenotrophomonas species (39/113) were the most frequently identified bacterial species. Most microbes identified were not associated with subjects underlying diagnoses, ventilator use, or feeding type. However, there was a significant association between upper-airway obstruction and group B Streptococcus species and G-tube with P. aeruginosa. Conclusions: This retrospective single-site descriptive cohort analysis of pediatric subjects with long-term tracheostomy identified trends in microbial prevalence. The presence of specific bacterial strains was more likely to follow individual subject trajectories than sequential appearance of species. P. aeruginosa was associated with G-tube and Streptococcus species with upper-airway obstruction. Ventilator dependence was not associated with specific microbial profiles.

The resurgence of invasive group A streptococcal (iGAS) infections and progress in GAS vaccine development emphasize the importance of understanding current trends in the epidemiology of iGAS. To describe the epidemiology of pediatric iGAS over a 32-year period. This case series uses population-based surveillance data for iGAS in Toronto and Peel Region, Canada, including emm typing from Canada's National Microbiology Laboratory and population data from Statistics Canada. All children (age <18 years) with iGAS from January 1, 1992, to December 31, 2023, were included. Data were analyzed from July 15, 2023, to September 1, 2024. Outcomes of interest were disease incidence over time and by age; variation in clinical presentation, disease severity, outcomes and infecting emm types; and antimicrobial resistance. Overall, 498 iGAS cases (300 [60.2%] male; median [IQR] age, 5.1 [2.7-8.6] years) occurred, including 151 (30.7%) in children with comorbidities. The most common presentations were soft tissue infection (140 cases [28.1%]) and bacteremia without focus (131 cases [26.3%]). iGAS incidence increased from 1.8 events per 100 000 population per year in 1992 to 2011 to 2.4 events per 100 000 population per year in 2012 to 2019 (incidence rate ratio, 1.3 [95% CI, 1.1-1.6]), with the increase occurring in GAS infections of the respiratory tract. Incidence declined to 1.2 events per 100 000 population per year in 2020 and 0.5 events per 100 000 population per year in 2021 before increasing to 6.0 events per 100 000 population per year in 2023. In 2022 to 2023, 18 of 56 children with iGAS (32.0%) had a viral respiratory coinfection. Varicella-associated iGAS cases declined from 23 of 137 children (16.8%) in 1992 to 2001 to 2 of 223 children (0.9%) in 2012 to 2023 (P < .001), after routine varicella vaccination implementation in 2004. Streptococcal toxic shock syndrome occurred in 29 children (5.8%), necrotizing fasciitis in 12 children (2.4%); 10 children (2.0%) died. The most common emm types were emm1 (182 of 471 isolates [38.6%]), emm12 (75 isolates [15.9%]), and emm4 (31 isolates [6.6%]). The M1UK subtype was first identified in 2019 and comprised 32 of 46 emm1 isolates (70.0%) from 2019 to 2023. Compared with other emm types, emm1 was more likely to be associated with pneumonia (odds ratio [OR], 1.99 [95% CI, 1.16-3.40]), bone and joint infections (OR, 1.70 [95% CI, 1.08-2.68]), and intensive care unit admission (OR, 1.67 [95% CI, 1.03-2.68]); emm4 was more likely to be associated with bacteremia without focus (OR, 6.10 [95% CI, 2.83-13.16]). Overall, 437 isolates (92.8%) were of emm types included in the 30-valent GAS vaccine. This case series found that pediatric iGAS incidence increased in south-central Ontario prior to and after the COVID-19 pandemic in association with increased iGAS infections of the respiratory tract. Respiratory viral coinfections were common. Different emm types were associated with differing presentations and severity.

To determine invasive group A Streptococcus trends in Canada, we characterized emm1 isolates collected during 2018-2023. The percentage of hypervirulent M1UK lineage isolates increased significantly, from 22.1% in 2018 to 60.2% in 2023. Genomic analysis identified geographically and temporally associated clusters and genes associated with virulent bacteriophage acquisition.

Epidemiologic research on zoonotic tuberculosis historically used Mycobacterium bovis as a surrogate measure; however, increased reports of human tuberculosis caused by other animal-associated Mycobacterium tuberculosis complex members like Mycobacterium orygis necessitates their inclusion. We performed a retrospective cohort study including persons infected with any animal-lineage M tuberculosis complex species in Alberta, Canada, from January 1995 to July 2021, identifying 42 patients (20 M bovis, 21 M orygis, 1 M caprae). Demographic, epidemiologic, and clinical characteristics were compared against persons with culture-confirmed M tuberculosis infection. The proportion of culture-positive infections caused by M orygis increased continuously from 2016 to 2020. Significantly more females at a higher median age were impacted by M orygis, with all patients originating from South Asia. Mycobacterium bovis caused significantly more extrapulmonary disease and disproportionately impacted young females, particularly those pregnant or postpartum. All infections were acquired abroad. These findings can aid in developing targeted public health interventions.

ABSTRACT The International Circumpolar Surveillance (ICS) program is a population-based surveillance network for invasive bacterial diseases throughout Arctic countries and territories. The ICS quality control program for Streptococcus pneumoniae serotyping and antimicrobial susceptibility testing has been ongoing since 1999. Current participating laboratories include the Provincial Laboratory for Public Health in Edmonton, Alberta; Laboratoire de santé publique du Québec in Sainte-Anne-de-Bellevue, Québec; the Centers for Disease Control’s Arctic Investigations Program in Anchorage, Alaska; the Neisseria and Streptococcus Reference Laboratory at Statens Serum Institut in Copenhagen, Denmark; the Department of Clinical Microbiology, Landspitali in Reykjavik, Iceland; and Public Health Agency of Canada’s National Microbiology Laboratory in Winnipeg, Manitoba. From 2009 to 2020, 140 isolates of S. pneumoniae were distributed among the six laboratories as part of the quality control program. Overall serotype concordance was 96.9%, with 99.3% concordance to pool level. All participating laboratories had individual concordance rates >92% for serotype and >97% for pool. Overall concordance by modal minimum inhibitory concentration (MIC) for testing done by broth microdilution or Etest was 99.1%, and >98% for all antimicrobials tested. Categorical concordance was >98% by both CLSI and EUCAST criteria. For two laboratories performing disc diffusion, rates of concordance by modal MIC were >97% for most antimicrobials, except chloramphenicol (>93%) and trimethoprim/sulfamethoxazole (>88%). Data collected from 12 years of the ICS quality control program for S. pneumoniae demonstrate excellent (≥95%) overall concordance for serotype and antimicrobial susceptibility testing results across six laboratories. IMPORTANCE Arctic populations experience several social and physical challenges that lead to the increased spread and incidence of invasive diseases. The International Circumpolar Surveillance (ICS) program was developed to monitor five invasive bacterial diseases in Arctic countries and territories. Each ICS organism has a corresponding interlaboratory quality control (QC) program for laboratory-based typing, to ensure the technical precision and accuracy of reference testing services for these regions, and identify and correct potential problems. Here, we describe the results of the ICS Streptococcus pneumoniae QC program, from 2009 to 2020. Excellent overall concordance was achieved for serotype and antimicrobial susceptibility testing results across six laboratories. Ongoing participation in these QC programs ensures the continuation of quality surveillance systems within Arctic populations that experience health disparities.

Background:Invasive group A streptococcal (iGAS, Streptococcus pyogenes) disease has been a nationally notifiable disease in Canada since 2000. This report summarizes the demographics, emm types, and antimicrobial resistance of iGAS isolates collected in Canada in 2021 and 2022.Methods:The Public Health Agency of Canada's National Microbiology Laboratory collaborates with provincial and territorial public health laboratories to conduct national surveillance of invasive S. pyogenes. Emm typing was performed using the Centers for Disease Control and Prevention emm sequencing protocol or extracted from whole-genome sequencing data. Antimicrobial susceptibilities were determined using Kirby-Bauer disk diffusion according to Clinical and Laboratory Standards Institute guidelines or predicted from whole-genome sequencing data based on the presence of resistance determinants.Results:Overall, the incidence of iGAS disease in Canada was 5.56 cases per 100,000 population in 2021, decreasing from the peak of 8.6 cases per 100,000 population in 2018. A total of 2,630 iGAS isolates were collected during 2022, representing an increase from 2021 (n=2,179). In particular, there was a large increase in isolates collected from October to December 2022. The most predominant emm type overall in 2021 and 2022 was emm49, at 21.5% (n=468) and 16.9% (n=444), respectively, representing a significant increase in prevalence since 2018 (p<0.0001). The former most prevalent type, emm1, increased from 0.5% (n=10) in 2021 to 4.8% (n=125) in 2022; similarly, emm12 increased from 1.0% (n=22) in 2021 to 5.8% (n=151) in 2022. These two types together accounted for almost 25% of isolates collected in late 2022 (October to December). Antimicrobial resistance rates in 2021 and 2022 included: 14.9%/14.1% erythromycin resistance, 4.8%/3.0% clindamycin resistance, and <1% chloramphenicol resistance.Conclusion:The increase of iGAS isolates collected in Canada is an important public health concern. Continued surveillance of iGAS is critical to monitor expanding emm types and antimicrobial resistance patterns.