Patryk Aftanas’s research while affiliated with Sunnybrook Health Sciences Centre and other places

The incorporation of sequencing technologies in frontline and public health healthcare settings was vital in developing virus surveillance programs during the Coronavirus Disease 2019 (COVID-19) pandemic caused by transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, increased data acquisition poses challenges for both rapid and accurate analyses. To overcome these hurdles, we developed the SARS-CoV-2 Illumina GeNome Assembly Line (SIGNAL) for quick bulk analyses of Illumina short-read sequencing data. SIGNAL is a Snakemake workflow that seamlessly manages parallel tasks to process large volumes of sequencing data. A series of outputs are generated, including consensus genomes, variant calls, lineage assessments and identified variants of concern (VOCs). Compared to other existing SARS-CoV-2 sequencing workflows, SIGNAL is one of the fastest-performing analysis tools while maintaining high accuracy. The source code is publicly available (github.com/jaleezyy/covid-19-signal) and is optimized to run on various systems, with software compatibility and resource management all handled within the workflow. Overall, SIGNAL illustrated its capacity for high-volume analyses through several contributions to publicly funded government public health surveillance programs and can be a valuable tool for continuing SARS-CoV-2 Illumina sequencing efforts and will inform the development of similar strategies for rapid viral sequence assessment.

Narrative) Hybrid whole genome sequencing was used to investigate if nosocomial Verona integron-encoded metallo-β-lactamase (VIM) carbapenemase transmission occurred between two patients without epidemiological links or common pathogens. Challenges in genomic methodology and appropriate analytical depth for mobile carbapenemase outbreaks are described including how inappropriate choices can mislead results and impact infection control practices.

In this verification study, we compare and contrast the performance characteristics of chromogenic agar culture, direct PCR, and broth enrichment followed by either culture or PCR, for the detection of C. auris colonization. We find that culture and PCR both offer excellent performance, with broth enrichment offering little performance advantage given its cost.

White-tailed deer (WTD) are susceptible to SARS-CoV-2 and represent an increasingly important species for surveillance. Samples from WTD (n=258) collected in November 2021 from Québec, Canada were analyzed for SARS-CoV-2 RNA. We employed viral genomics and host transcriptomics to further characterize infection and investigate host response. We detected Delta SARS-CoV-2 (B.1.617.2) in WTD from the Estrie region; sequences clustered with human sequences from October 2021 from Vermont, USA, which borders this region. Mutations in the S-gene and a deletion in ORF8 were detected. Host expression patterns in SARS-CoV-2 infected WTD were associated with the innate immune response, including signalling pathways related to anti-viral, pro- and anti-inflammatory signalling, and host damage. We found limited correlation between genes associated with innate immune response from human and WTD nasal samples, suggesting differences in response to SARS-CoV-2 infection. Our findings provide preliminary insights into host response to SARS-CoV-2 infection in naturally infected WTD.

Background Remdesivir (RDV) has been shown to reduce hospitalization and mortality in COVID‐19 patients. Resistance mutations caused by RDV are rare and have been predominantly reported in patients who are on prolonged therapy and immunocompromised. We investigate the effects of RDV treatment on intra‐host SARS‐CoV‐2 diversity and low‐frequency mutations in moderately ill hospitalized COVID‐19 patients and compare them to patients without RDV treatment. Methods From March 2020 to April 2022, sequential collections of nasopharyngeal and mid‐turbinate swabs were obtained from 14 patients with and 30 patients without RDV treatment. Demographic and clinical data on all patients were reviewed. A total of 109 samples were sequenced and mutation analyses were performed. Results Previously reported drug resistant mutations in nsp12 were not identified during short courses of RDV therapy. In genes encoding and surrounding the replication complex (nsp6‐nsp14), low‐frequency minority variants were detected in 7/14 (50%) and 18/30 (60%) patients with and without RDV treatment, respectively. We did not detect significant differences in within‐host diversity and positive selection between the RDV‐treated and untreated groups. Conclusions Minimal intra‐host variability and stochastic low‐frequency variants detected in moderately ill patients suggests little selective pressure in patients receiving short courses of RDV. The barrier to RDV resistance is high in patients with moderate disease. Patients undergoing short regimens of RDV therapy should continue to be monitored.

Background: Lachnoanaerobaculum orale is a newly described, obligately anaerobic gram-positive bacillus. The first report of invasive disease caused by L. orale was described in a patient with acute lymphocytic leukemia following systematic chemotherapy. Here we describe another case of L. orale bacteremia in a patient with a hematologic malignancy following chemotherapy-induced neutropenia. Methods: We present a case of a 46-year-old woman with a recent diagnosis of AML who presented to Sunnybrook Health Sciences Center with febrile neutropenia following induction chemotherapy with daunorubicin-cytarabine (3 +7 regimen) with Gemtuzumab and Ozogamycin. Despite being on intravenous pipercillin-tazobactam she remained febrile. Following our clinical assessment and investigations, potential sources of infection included a swollen digit and severe mucositis. Results: One blood culture from admission grew Lachnoanaerobaculum orale in the anaerobic bottle, identified by Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF). The isolate also underwent whole-genome sequencing using methods that have been described previously. Results demonstrated the organism was susceptible to cefoxitin, clindamycin, meropenem, metronidazole, penicillin, and piperacillin-tazobactam. We concluded that the source of this patient's bloodstream infection to be chemotherapy-induced stomatitis. Conclusion: With the increasing use of intensive immunosuppressive regimens and hematopoietic stem cell transplantation for patients with hematologic malignancies, there has been an increase in the incidence and detection of bloodstream infections due to anaerobic organisms. This is only the second case report of L. orale bacteremia, highlighting its emerging role as an opportunistic pathogen in immunocompromised patients.

Background: We investigate the effects of remdesivir (RDV) treatment on intra-host SARS-CoV-2 diversity and low-frequency mutations in moderately ill hospitalized COVID-19 patients and compare them to patients without RDV treatment. Methods: Sequential collections of nasopharyngeal and mid-turbinate swabs were obtained from 16 patients with and 31 patients without RDV treatment. A total of 113 samples were sequenced and mutation analyses were performed. Results: We did not identify any drug resistant mutations during RDV therapy. In genes encoding and associated with the replication complex, low-frequency minority variants that do not reach fixation within the sampling period were detected in 6/16 (37.5%) and 14/31 (45%) patients with and without RDV treatment respectively. We did not detect significant differences in within-host diversity and positive selection between the RDV-treated and untreated groups. Conclusions: Minimal intra-host variability and stochastic low-frequency variants detected in moderately ill patients suggests little selective pressure in patients receiving short courses of RDV. Patients undergoing short regimens of RDV therapy should continue to be monitored.

Wildlife reservoirs of broad-host-range viruses have the potential to enable evolution of viral variants that can emerge to infect humans. In North America, there is phylogenomic evidence of continual transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from humans to white-tailed deer (Odocoileus virginianus) through unknown means, but no evidence of transmission from deer to humans. We carried out an observational surveillance study in Ontario, Canada during November and December 2021 (n = 300 deer) and identified a highly divergent lineage of SARS-CoV-2 in white-tailed deer (B.1.641). This lineage is one of the most divergent SARS-CoV-2 lineages identified so far, with 76 mutations (including 37 previously associated with non-human mammalian hosts). From a set of five complete and two partial deer-derived viral genomes we applied phylogenomic, recombination, selection and mutation spectrum analyses, which provided evidence for evolution and transmission in deer and a shared ancestry with mink-derived virus. Our analysis also revealed an epidemiologically linked human infection. Taken together, our findings provide evidence for sustained evolution of SARS-CoV-2 in white-tailed deer and of deer-to-human transmission.

The Association of Medical Microbiology and Infectious Disease Canada Conference–AMMI 2022, Vancouver, British Columbia, Canada.