Genomic characterization of emerging invasive Streptococcus agalactiae serotype VIII in Alberta, Canada.

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. Trends in descriptive clinical data and antimicrobial susceptibility results were evaluated for invasive serotype VIII isolates from Alberta. Isolate genomes were sequenced and subjected to molecular sequence typing, virulence and antimicrobial resistance gene identification, phylogenetic analysis, and pangenome determination. Multilocus sequencing typing identified eight ST42 (Clonal Complex; CC19), four ST1 (CC1), and two ST2 (CC1) profiles. Isolates were susceptible to penicillin, erythromycin, chloramphenicol, and clindamycin, apart from one isolate that displayed erythromycin and inducible clindamycin resistance. All isolates carried genes for peptide antibiotic resistance, three isolates for tetracycline resistance, and one for macrolide, lincosamide, and streptogramin resistance. All genomes carried targets currently being considered for protein-based vaccines (e.g., pili and/or Alpha family proteins). Overall, invasive GBS serotype VIII is emerging in Alberta, primarily due to ST42. Characterization and continued surveillance of serotype VIII will be important for outbreak prevention, informing vaccine development, and contributing to our understanding of the global epidemiology of this rare serotype.

Phenotypic changes in group B streptococci grown in the presence of the polyols, erythritol, sorbitol and mannitol.

BACKGROUND: Group B streptococci (GBS) are important neonatal bacterial pathogens that can cause severe invasive disease in the newborn. It is thought that in many cases of invasive neonatal GBS disease, the bacteria ascend the vagina into the uterus and infect the amniotic fluid surrounding the fetus. Important constituents of this environment include the polyols or sugar alcohols of which erythritol, sorbitol and mannitol are examples. The aim of our study was to investigate the effect of polyols on GBS grown in media containing these sugar alcohols. RESULTS: GBS incubated in varying concentrations of polyols (erythritol, sorbitol or mannitol) did not display any significant enhancement or inhibition of bacterial growth. However, growth of GBS in the presence of erythritol significantly increased the surface expression of GBS-PGK (a plasminogen binding protein) 1.25 to 1.5-fold depending on the erythritol concentration and significantly enhanced the survival in human blood 3X to 18X depending on the concentration of polyol used. Interestingly, GBS grown in 1% erythritol significantly increased invasion by the bacteria of HeLa cells (epithelial cell line) (150% vs 100%) however, at higher concentrations (2% or 4% of polyol) the number of CFUs was significantly reduced (55-75% vs 100%) suggesting higher concentrations of polyols may inhibit invasion. Erythritol also increased GBS hemolytic activity as well as enhancing biofilm formation 1.4X to 3.3X depending on the concentration of polyol used. CONCLUSIONS: GBS grown in the presence of polyols alters the bacteria's phenotype resulting in changes associated with GBS virulence. This effect was greatest for the polyol erythritol.

Mycobacterium chimaera Encephalitis Following Cardiac Surgery: A New Syndrome.

We report the cases of 3 patients with fatal, disseminated Mycobacterium chimaera infections following cardiac surgeries. Progressive neurocognitive decline and death were explained by active granulomatous encephalitis, with widespread involvement of other organs. This syndrome is clinically elusive and, thus, may have caused deaths in prior reported series.

Interim estimates of 2019/20 vaccine effectiveness during early-season co-circulation of influenza A and B viruses, Canada, February 2020.

Interim results from Canada's Sentinel Practitioner Surveillance Network show that during a season characterised by early co-circulation of influenza A and B viruses, the 2019/20 influenza vaccine has provided substantial protection against medically-attended influenza illness. Adjusted VE overall was 58% (95% confidence interval (CI): 47 to 66): 44% (95% CI: 26 to 58) for A(H1N1)pdm09, 62% (95% CI: 37 to 77) for A(H3N2) and 69% (95% CI: 57 to 77) for influenza B viruses, predominantly B/Victoria lineage.

The use of genome sequencing to investigate an outbreak of hospital-acquired mucormycosis in transplant patients.

We report three cases of hospital-acquired mucormycosis in heart and lung transplant patients over a 6-month period. Traditional epidemiological investigation tools were used to look for a common link between patients to explain the outbreak. Genome sequencing of each fungal strain was used to supplement the investigation. By disproving a close genetic link between infecting strains of mucormycosis, we were able to conclude the outbreak investigation. Genome sequencing is a novel tool that can be used in addition to traditional epidemiologic investigations to help determine linkage of patients during outbreak investigations.

Interim estimates of 2018/19 vaccine effectiveness against influenza A(H1N1)pdm09, Canada, January 2019.

Using a test-negative design, the Canadian Sentinel Practitioner Surveillance Network assessed interim 2018/19 vaccine effectiveness (VE) against predominant influenza A(H1N1)pdm09 viruses. Adjusted VE was 72% (95% confidence interval: 60 to 81) against medically attended, laboratory-confirmed influenza A(H1N1)pdm09 illness. This substantial vaccine protection was observed in all age groups, notably young children who appeared to be disproportionately affected. Sequence analysis identified heterogeneity in emerging clade 6B.1 viruses but no dominant drift variant.

Children under 10 years of age were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic in Canada: possible cohort effect following the 2009 influenza pandemic.

IntroductionFindings from the community-based Canadian Sentinel Practitioner Surveillance Network (SPSN) suggest children were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic.AimTo compare the age distribution of A(H1N1)pdm09 cases in 2018/19 to prior seasonal influenza epidemics in Canada.MethodsThe age distribution of unvaccinated influenza A(H1N1)pdm09 cases and test-negative controls were compared across A(H1N1)pdm09-dominant epidemics in 2018/19, 2015/16 and 2013/14 and with the general population of SPSN provinces. Similar comparisons were undertaken for influenza A(H3N2)-dominant epidemics.ResultsIn 2018/19, more influenza A(H1N1)pdm09 cases were under 10 years old than controls (29% vs 16%; p < 0.001). In particular, children aged 5-9 years comprised 14% of cases, greater than their contribution to controls (4%) or the general population (5%) and at least twice their contribution in 2015/16 (7%; p < 0.001) or 2013/14 (5%; p < 0.001). Conversely, children aged 10-19 years (11% of the population) were under-represented among A(H1N1)pdm09 cases versus controls in 2018/19 (7% vs 12%; p < 0.001), 2015/16 (7% vs 13%; p < 0.001) and 2013/14 (9% vs 12%; p = 0.12).ConclusionChildren under 10 years old contributed more to outpatient A(H1N1)pdm09 medical visits in 2018/19 than prior seasonal epidemics in Canada. In 2018/19, all children under 10 years old were born after the 2009 A(H1N1)pdm09 pandemic and therefore lacked pandemic-induced immunity. In addition, more than half those born after 2009 now attend school (i.e. 5-9-year-olds), a socio-behavioural context that may enhance transmission and did not apply during prior A(H1N1)pdm09 epidemics.

Paradoxical clade- and age-specific vaccine effectiveness during the 2018/19 influenza A(H3N2) epidemic in Canada: potential imprint-regulated effect of vaccine (I-REV).

IntroductionThe Canadian Sentinel Practitioner Surveillance Network reports vaccine effectiveness (VE) for the 2018/19 influenza A(H3N2) epidemic.AimTo explain a paradoxical signal of increased clade 3C.3a risk among 35-54-year-old vaccinees, we hypothesise childhood immunological imprinting and a cohort effect following the 1968 influenza A(H3N2) pandemic.MethodsWe assessed VE by test-negative design for influenza A(H3N2) overall and for co-circulating clades 3C.2a1b and 3C.3a. VE variation by age in 2018/19 was compared with amino acid variation in the haemagglutinin glycoprotein by year since 1968.ResultsInfluenza A(H3N2) VE was 17% (95% CI: -13 to 39) overall: 27% (95% CI: -7 to 50) for 3C.2a1b and -32% (95% CI: -119 to 21) for 3C.3a. Among 20-64-year-olds, VE was -7% (95% CI: -56 to 26): 6% (95% CI: -49 to 41) for 3C.2a1b and -96% (95% CI: -277 to -2) for 3C.3a. Clade 3C.3a VE showed a pronounced negative dip among 35-54-year-olds in whom the odds of medically attended illness were > 4-fold increased for vaccinated vs unvaccinated participants (p < 0.005). This age group was primed in childhood to influenza A(H3N2) viruses that for two decades following the 1968 pandemic bore a serine at haemagglutinin position 159, in common with contemporary 3C.3a viruses but mismatched to 3C.2a vaccine strains instead bearing tyrosine.DiscussionImprinting by the first childhood influenza infection is known to confer long-lasting immunity focused toward priming epitopes. Our findings suggest vaccine mismatch may negatively interact with imprinted immunity. The immunological mechanisms for imprint-regulated effect of vaccine (I-REV) warrant investigation.

The Cutaneous Microbiome: Implications for Dermatology Practice.

The human integument is inhabited by a vast array of microorganisms known collectively as the cutaneous microbiome. As a result of advances in laboratory science, our understanding of the diversity and complexity of the human microbiome is rapidly evolving. In particular, advances in the field of genomics have enabled the study of the cutaneous microbiome with a hitherto unimaginable level of detail, resulting in a maturation of our understanding of cutaneous health and disease. Herein, we review current microbiology concepts and highlight the key features of recent laboratory advances, particularly with respect to genomics. We provide a summary of new findings related to normal skin flora, interactions between host immunity and microbial communities, and microbial relationships with common skin disorders. Finally, we review the implications for dermatologists.

Quantitative Mass Spectrometry Identifies Novel Host Binding Partners for Pathogenic Escherichia coli Type III Secretion System Effectors.

Enteropathogenic and enterohemorrhagic Escherichia coli cause enteric diseases resulting in significant morbidity and mortality worldwide. These pathogens remain extracellular and translocate a set of type III secreted effector proteins into host cells to promote bacterial virulence. Effectors manipulate host cell pathways to facilitate infection by interacting with a variety of host targets, yet the binding partners and mechanism of action of many effectors remain elusive. We performed a mass spectrometry screen to identify host targets for a library of effectors. We found five known effector targets and discovered four novel interactions. Interestingly, we identified multiple effectors that interacted with the microtubule associated protein, ensconsin. Using co-immunoprecipitations, we confirmed that NleB1 and EspL interacted with ensconsin in a region that corresponded to its microtubule binding domain. Ensconsin is an essential cofactor of kinesin-1 that is required for intracellular trafficking, and we demonstrated that intracellular trafficking was severely disrupted during wild type EPEC infections but not during infections with ΔnleB1 or ΔespL mutants. Our findings demonstrate the efficacy of quantitative proteomics for identifying effector-host protein interactions and suggest that vesicular trafficking is a crucial cellular process that may be targeted by NleB1 and EspL through their interaction with ensconsin.

Pooled Nucleic Acid Amplification Test for Screening of Stool Specimens for Shiga Toxin-Producing Escherichia coli.

Shiga toxin-producing Escherichia coli (STEC)-associated enteric illness is attributed to O157 and non-O157 serotypes; however, traditional culture-based methods underdetect non-O157 STEC. Labor and cost of consumables are major barriers to implementation of the CDC recommendation to test all stools for both O157 and non-O157 serotypes. We evaluated the feasibility of a pooled nucleic acid amplification test (NAAT) as an approach for screening stool specimens for STEC. For retrospective evaluation, 300 stool specimens were used to create pools of 10 samples each. The sensitivity was 83% for the preenrichment pooling strategy and 100% for the postenrichment pooling strategy compared with those for individual NAAT results. The difference in cycle threshold (CT) between individual and pooled NAAT results for specimens was significantly lower and more consistent for postenrichment pooling (stx1 mean = 3.90, stx2 mean = 4.28) than those for preenrichment pooling (excluding undetected specimens; stx1 mean = 9.34, stx2 mean = 8.96) (P ≤ 0.0013). Cost of consumables and labor time savings of 48 to 81% and 6 to 66%, respectively, were estimated for the testing of 90 specimens by the postenrichment pooled NAAT strategy on the basis of an expected 1 to 2% positivity rate. A 30-day prospective head-to-head clinical trial involving 512 specimens confirmed the sensitivity and labor savings associated with the postenrichment pooled NAAT strategy. The postenrichment pooled NAAT strategy described here is suitable for efficient large-scale surveillance of all STEC serotypes. Comprehensive detection of STEC will result in accurate estimation of STEC burden and, consequently, appropriate public health interventions.

Epidemiologic and Genotypic Review of Carbapenemase-Producing Organisms in British Columbia, Canada, between 2008 and 2014.

Carbapenemase-producing organisms (CPOs) are a serious emerging problem for health care facilities worldwide. Owing to their resistance to most antimicrobial therapies, CPOs are difficult to treat and pose a challenge for infection prevention and control. Since 2010, lab-based surveillance for CPOs and PCR-based testing were implemented in British Columbia (BC), Canada. A review of CPOs in BC from 2008 to March 2014 was done to characterize the resistance mechanisms and possible clonal strain transmission and to compare pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and plasmid restriction fragment length polymorphism (RFLP) as molecular typing tools. During this study period, a total of 177 CPO cases were identified. Patient demographics and travel history were reviewed, and a descriptive analysis was carried out. PFGE profiles, MLST, and plasmid RFLP analysis for a subset of Escherichia coli, Klebsiella pneumoniae, and Enterobacter species isolates were obtained and analyzed. Our findings demonstrate that CPOs have been increasing in number in BC over time, from 1 isolate/year retrospectively identified in 2008 and 2009 to 82 isolates in 2013 and 30 isolates in the first quarter of 2014. Overall, K. pneumoniae isolates lack clonality, although some seemingly related clusters have been found. Plasmid analysis showed evidence of the spread of plasmids carrying carbapenemase-encoding genes between the examined isolates. Analysis of Enterobacter cloacae isolates revealed a more clonal nature of these CPOs in BC. The presence of related clusters provides evidence of interpatient organism transmission both within and between institutions. Although in our study, NDM-harboring E. cloacae isolates appeared to spread clonally, the spread of carbapenem resistance in K. pneumoniae seems to be plasmid mediated.

Identification and regulation of a novel Citrobacter rodentium gut colonization fimbria (Gcf).

UNLABELLED: The Gram-negative enteric bacterium Citrobacter rodentium is a natural mouse pathogen that has been extensively used as a surrogate model for studying the human pathogens enteropathogenic and enterohemorrhagic Escherichia coli. All three pathogens produce similar attaching and effacing (A/E) lesions in the intestinal epithelium. During infection, these bacteria employ surface structures called fimbriae to adhere and colonize the host intestinal epithelium. For C. rodentium, the roles of only a small number of its genome-carried fimbrial operons have been evaluated. Here, we report the identification of a novel C. rodentium colonization factor, called gut colonization fimbria (Gcf), which is encoded by a chaperone-usher fimbrial operon. A gcfA mutant shows a severe colonization defect within the first 10 days of infection. The gcf promoter is not active in C. rodentium under several in vitro growth conditions; however, it is readily expressed in a C. rodentium Δhns1 mutant lacking the closest ortholog of the Escherichia coli histone-like nucleoid structuring protein (H-NS) but not in mutants with deletion of the other four genes encoding H-NS homologs. H-NS binds to the regulatory region of gcf, further supporting its direct role as a repressor of the gcf promoter that starts transcription 158 bp upstream of the start codon of its first open reading frame. The gcf operon possesses interesting novel traits that open future opportunities to expand our knowledge of the structure, regulation, and function during infection of these important bacterial structures. IMPORTANCE: Fimbriae are surface bacterial structures implicated in a variety of biological processes. Some have been shown to play a critical role during host colonization and thus in disease. Pathogenic bacteria possess the genetic information for an assortment of fimbriae, but their function and regulation and the interplay between them have not been studied in detail. This work provides new insights into the function and regulation of a novel fimbria called Gcf that is important for early establishment of a successful infection by C. rodentium in mice, despite being poorly expressed under in vitro growth conditions. This discovery offers an opportunity to better understand the individual role and the regulatory mechanisms controlling the expression of specific fimbrial operons that are critical during infection.

Recent advances in understanding enteric pathogenic Escherichia coli.

Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.

The Canadian VirusSeq Data Portal & Duotang: open resources for SARS-CoV-2 viral sequences and genomic epidemiology.

The COVID-19 pandemic led to a large global effort to sequence SARS-CoV-2 genomes from patient samples to track viral evolution and inform public health response. Millions of SARS-CoV-2 genome sequences have been deposited in global public repositories. The Canadian COVID-19 Genomics Network (CanCOGeN - VirusSeq), a consortium tasked with coordinating expanded sequencing of SARS-CoV-2 genomes across Canada early in the pandemic, created the Canadian VirusSeq Data Portal, with associated data pipelines and procedures, to support these efforts. The goal of VirusSeq was to allow open access to Canadian SARS-CoV-2 genomic sequences and enhanced, standardized contextual data that were unavailable in other repositories and that meet FAIR standards (Findable, Accessible, Interoperable and Reusable). In addition, the Portal data submission pipeline contains data quality checking procedures and appropriate acknowledgement of data generators that encourages collaboration. From inception to execution, the portal was developed with a conscientious focus on strong data governance principles and practices. Extensive efforts ensured a commitment to Canadian privacy laws, data security standards, and organizational processes. This Portal has been coupled with other resources like Viral AI and was further leveraged by the Coronavirus Variants Rapid Response Network (CoVaRR-Net) to produce a suite of continually updated analytical tools and notebooks. Here we highlight this Portal, including its contextual data not available elsewhere, and the 'Duotang', a web platform that presents key genomic epidemiology and modeling analyses on circulating and emerging SARS-CoV-2 variants in Canada. Duotang presents dynamic changes in variant composition of SARS-CoV-2 in Canada and by province, estimates variant growth, and displays complementary interactive visualizations, with a text overview of the current situation. The VirusSeq Data Portal and Duotang resources, alongside additional analyses and resources computed from the Portal (COVID-MVP, CoVizu), are all open-source and freely available. Together, they provide an updated picture of SARS-CoV-2 evolution to spur scientific discussions, inform public discourse, and support communication with and within public health authorities. They also serve as a framework for other jurisdictions interested in open, collaborative sequence data sharing and analyses.

The Canadian VirusSeq Data Portal and Duotang: open resources for SARS-CoV-2 viral sequences and genomic epidemiology.

The COVID-19 pandemic led to a large global effort to sequence SARS-CoV-2 genomes from patient samples to track viral evolution and inform the public health response. Millions of SARS-CoV-2 genome sequences have been deposited in global public repositories. The Canadian COVID-19 Genomics Network (CanCOGeN - VirusSeq), a consortium tasked with coordinating expanded sequencing of SARS-CoV-2 genomes across Canada early in the pandemic, created the Canadian VirusSeq Data Portal, with associated data pipelines and procedures, to support these efforts. The goal of VirusSeq was to allow open access to Canadian SARS-CoV-2 genomic sequences and enhanced, standardized contextual data that were unavailable in other repositories and that meet FAIR standards (Findable, Accessible, Interoperable and Reusable). In addition, the portal data submission pipeline contains data quality checking procedures and appropriate acknowledgement of data generators that encourages collaboration. From inception to execution, the portal was developed with a conscientious focus on strong data governance principles and practices. Extensive efforts ensured a commitment to Canadian privacy laws, data security standards, and organizational processes. This portal has been coupled with other resources, such as Viral AI, and was further leveraged by the Coronavirus Variants Rapid Response Network (CoVaRR-Net) to produce a suite of continually updated analytical tools and notebooks. Here we highlight this portal (https://virusseq-dataportal.ca/), including its contextual data not available elsewhere, and the Duotang (https://covarr-net.github.io/duotang/duotang.html), a web platform that presents key genomic epidemiology and modelling analyses on circulating and emerging SARS-CoV-2 variants in Canada. Duotang presents dynamic changes in variant composition of SARS-CoV-2 in Canada and by province, estimates variant growth, and displays complementary interactive visualizations, with a text overview of the current situation. The VirusSeq Data Portal and Duotang resources, alongside additional analyses and resources computed from the portal (COVID-MVP, CoVizu), are all open source and freely available. Together, they provide an updated picture of SARS-CoV-2 evolution to spur scientific discussions, inform public discourse, and support communication with and within public health authorities. They also serve as a framework for other jurisdictions interested in open, collaborative sequence data sharing and analyses.

Genomic survey maps differences in the molecular complement of vesicle formation machinery between Giardia intestinalis assemblages.

Giardia intestinalis is a globally important microbial pathogen with considerable public health, agricultural, and economic burden. Genome sequencing and comparative analyses have elucidated G. intestinalis to be a taxonomically diverse species consisting of at least eight different sub-types (assemblages A-H) that can infect a great variety of animal hosts, including humans. The best studied of these are assemblages A and B which have a broad host range and have zoonotic transmissibility towards humans where clinical Giardiasis can range from asymptomatic to diarrheal disease. Epidemiological surveys as well as previous molecular investigations have pointed towards critical genomic level differences within numerous molecular pathways and families of parasite virulence factors within assemblage A and B isolates. In this study, we explored the necessary machinery for the formation of vesicles and cargo transport in 89 Canadian isolates of assemblage A and B G. intestinalis. Considerable variability within the molecular complement of the endolysosomal ESCRT protein machinery, adaptor coat protein complexes, and ARF regulatory system have previously been reported. Here, we confirm inter-assemblage, but find no intra-assemblage variation within the trafficking systems examined. This variation includes losses of subunits belonging to the ESCRTIII as well as novel lineage specific duplications in components of the COPII machinery, ARF1, and ARFGEF families (BIG and CYTH). Since differences in disease manifestation between assemblages A and B have been controversially reported, our findings may well have clinical implications and even taxonomic, as the membrane trafficking system underpin parasite survival, pathogenesis, and propagation.

Tracking SARS-CoV-2 Omicron lineages using real-time reverse transcriptase PCR assays and prospective comparison with genome sequencing.

Omicron has become the dominant SARS-CoV-2 variant globally since December 2021, with distinct waves being associated with separate Omicron sublineages. Rapid detection of BA.1, BA.2, BA.4, and BA.5 was accomplished in the province of Alberta, Canada, through the design and implementation of real-time reverse transcriptase PCR assays targeting S:N501Y, S:ins214EPE, S:H69/V70, ORF7b:L11F, and M:D3N. Using the combination of results for each of these markers, samples could be designated as belonging to sublineages within BA.1, BA.2, BA.4, or BA.5. The analytical sensitivity of these markers ranged from 132 to 2229 copies/mL and in-laboratory accuracy was 98.9-100%. A 97.3% agreement using 12,592 specimens was demonstrated for the assays compared to genome sequencing. The use of these assays, combined with genome sequencing, facilitated the surveillance of SARS-CoV-2 lineages throughout a BA.5-dominated period.

Genomic analysis of Streptococcus pneumoniae serogroup 20 isolates in Alberta, Canada from 1993-2019.

In the province of Alberta, Canada, invasive disease caused by Streptococcus pneumoniae 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. Two hundred and seventy-four serogroup 20 isolates from Alberta were sequenced, and analysed along with 95 GPS Project genomes. The majority of invasive Alberta serogroup 20 isolates were identified after 2007 in primarily middle-aged adults and typed predominantly as ST235, a sequence type that was rare among GPS Project isolates. Most Alberta isolates carried a full-length whaF capsular gene, suggestive of serotype 20B. All Alberta and GPS Project genomes carried molecular resistance determinants implicated in fluoroquinolone and macrolide resistance, with a few Alberta isolates exhibiting phenotypic resistance to azithromycin, clindamycin, erythromycin, tetracycline and trimethoprim-sulfamethoxazole, as well as non-susceptibility to tigecycline. All isolates carried multiple virulence factors including those involved in adherence, immune modulation and nutrient uptake, as well as exotoxins and exoenzymes. Phylogenetically, Alberta serogroup 20 isolates clustered with predominantly invasive GPS Project isolates from the USA, Israel, Brazil and Nepal. Overall, this study highlights the increasing incidence of invasive S. pneumoniae serogroup 20 disease in Alberta, Canada, and provides insights into the genetic and clinical characteristics of these isolates within a global context.

Patient and ward related risk factors in a multi-ward nosocomial outbreak of COVID-19: Outbreak investigation and matched case-control study.

BACKGROUND: Risk factors for nosocomial COVID-19 outbreaks continue to evolve. The aim of this study was to investigate a multi-ward nosocomial outbreak of COVID-19 between 1st September and 15th November 2020, occurring in a setting without vaccination for any healthcare workers or patients. METHODS: Outbreak report and retrospective, matched case-control study using incidence density sampling in three cardiac wards in an 1100-bed tertiary teaching hospital in Calgary, Alberta, Canada. Patients were confirmed/probable COVID-19 cases and contemporaneous control patients without COVID-19. COVID-19 outbreak definitions were based on Public Health guidelines. Clinical and environmental specimens were tested by RT-PCR and as applicable quantitative viral cultures and whole genome sequencing were conducted. Controls were inpatients on the cardiac wards during the study period confirmed to be without COVID-19, matched to outbreak cases by time of symptom onset dates, age within ± 15 years and were admitted in hospital for at least 2 days. Demographics, Braden Score, baseline medications, laboratory measures, co-morbidities, and hospitalization characteristics were collected on cases and controls. Univariate and multivariate conditional logistical regression was used to identify independent risk factors for nosocomial COVID-19. RESULTS: The outbreak involved 42 healthcare workers and 39 patients. The strongest independent risk factor for nosocomial COVID-19 (IRR 3.21, 95% CI 1.47-7.02) was exposure in a multi-bedded room. Of 45 strains successfully sequenced, 44 (97.8%) were B.1.128 and differed from the most common circulating community lineages. SARS-CoV-2 positive cultures were detected in 56.7% (34/60) of clinical and environmental specimens. The multidisciplinary outbreak team observed eleven contributing events to transmission during the outbreak. CONCLUSIONS: Transmission routes of SARS-CoV-2 in hospital outbreaks are complex; however multi-bedded rooms play a significant role in the transmission of SARS-CoV-2.