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Objective: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hospital outbreaks have been common and devastating during the coronavirus disease 2019 (COVID-19) pandemic. Understanding SARS-CoV-2 transmission in these environments is critical for preventing and managing outbreaks. Design: Outbreak investigation through epidemiological mapping and whole-genome sequencing phylogeny. Setting: Hospital in-patient medical unit outbreak in Toronto, Canada, from November 2020 to January 2021. Participants: The outbreak involved 8 patients and 10 staff and was associated with 3 patient deaths. Results: Patients being cared for in geriatric chairs at the nursing station were at high risk for both acquiring and transmitting SARS-CoV-2 to other patients and staff. Furthermore, given the informal nature of these transmissions, they were not initially recognized, which led to further transmission and missing the opportunity for preventative COVID-19 therapies. Conclusions: During outbreak prevention and management, the risk of informal patient care settings, such as geriatric chairs, should be considered. During high-risk periods or during outbreaks, efforts should be made to care for patients in their rooms when possible.

The mRNA COVID vaccines are only licensed for intramuscular injection but it is unclear whether successful intramuscular administration is required for immunogenicity.In this observational study, eligible adults receiving their first ComirnatyParticipants (n = 402) had a mean age of 34.7 years, BMI 29.1 kg/mA 25 mm needle length is likely to be inadequate to ensure vaccine deposition within the deltoid muscle in a small proportion of adults. Vaccine-induced spike antibody titres were comparable in those vaccinated with a needle of sufficient versus insufficient length suggesting deltoid muscle deposition may not be required for an adequate antibody response to mRNA vaccines.

The ability of a third dose of the Pfizer-BioNTech BNT162b2 SARS-CoV-2 vaccine to stimulate immune responses against subvariants, including Omicron BA.1, has not been assessed in New Zealand populations. Unlike many overseas populations, New Zealanders were largely infection naïve at the time they were boosted. This adult cohort of 298 participants, oversampled for at-risk populations, was composed of 29% Māori and 28% Pacific peoples, with 40% of the population aged 55+. A significant proportion of the cohort was obese and presented with at least one comorbidity. Sera were collected 28 days and 6 months post second vaccination and 28 days post third vaccination. SARS-CoV-2 anti-S IgG titres and neutralising capacity using surrogate viral neutralisation assays against variants of concern, including Omicron BA.1, were investigated. The incidence of SARS-CoV-2 infection, within our cohort, prior to third vaccination was very low (

Background We determined the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in air and on surfaces in rooms of patients hospitalized with coronavirus disease 2019 (COVID-19) and investigated patient characteristics associated with SARS-CoV-2 environmental contamination. Methods Nasopharyngeal swabs, surface, and air samples were collected from the rooms of 78 inpatients with COVID-19 at 6 acute care hospitals in Toronto from March to May 2020. Samples were tested for SARS-CoV-2 ribonucleic acid (RNA), cultured to determine potential infectivity, and whole viral genomes were sequenced. Association between patient factors and detection of SARS-CoV-2 RNA in surface samples were investigated. Results Severe acute respiratory syndrome coronavirus 2 RNA was detected from surfaces (125 of 474 samples; 42 of 78 patients) and air (3 of 146 samples; 3 of 45 patients); 17% (6 of 36) of surface samples from 3 patients yielded viable virus. Viral sequences from nasopharyngeal and surface samples clustered by patient. Multivariable analysis indicated hypoxia at admission, polymerase chain reaction-positive nasopharyngeal swab (cycle threshold of ≤30) on or after surface sampling date, higher Charlson comorbidity score, and shorter time from onset of illness to sampling date were significantly associated with detection of SARS-CoV-2 RNA in surface samples. Conclusions The infrequent recovery of infectious SARS-CoV-2 virus from the environment suggests that the risk to healthcare workers from air and near-patient surfaces in acute care hospital wards is likely limited.

SummaryTP53 is the most commonly mutated gene in human cancer, typically occurring in association with complex cytogenetics and dismal outcomes. Understanding the genetic and non-genetic determinants of TP53-mutation driven clonal evolution and subsequent transformation is a crucial step towards the design of rational therapeutic strategies. Here, we carry out allelic resolution single-cell multi-omic analysis of haematopoietic stem/progenitor cells (HSPC) from patients with a myeloproliferative neoplasm who transform to TP53-mutant secondary acute myeloid leukaemia (AML), a tractable model of TP53-mutant cancer evolution. All patients showed dominant TP53 ‘multi-hit’ HSPC clones at transformation, with a leukaemia stem cell transcriptional signature strongly predictive of adverse outcome in independent cohorts, across both TP53-mutant and wild-type AML. Through analysis of serial samples and antecedent TP53-heterozygous clones, we demonstrate a hitherto unrecognised effect of chronic inflammation, which supressed TP53 wild-type HSPC whilst enhancing the fitness advantage of TP53 mutant cells. Our findings will facilitate the development of risk-stratification, early detection and treatment strategies for TP53-mutant leukaemia, and are of broader relevance to other cancer types.

BACKGROUND: Testing for antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been instrumental in detecting previous exposures and analyzing vaccine-elicited immune responses. Here, we describe a scalable "Made-in-Canada" solution that can detect and quantify SARS-CoV-2 antibodies, discriminate between natural infection- and vaccination-induced responses, and assess antibody-mediated inhibition of the spike-angiotensin converting enzyme 2 (ACE2) interaction. METHODS: We developed a set of methods and reagents to detect SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA). The main assays focus on the parallel detection of immunoglobulin (Ig)Gs against the spike trimer, its receptor binding domain (RBD), and the nucleocapsid (N) protein. These antigens are complemented by a detection antibody (human anti-IgG fused to horseradish peroxidase (HRP)) and a positive control reference antibody (recombinant IgG against the RBD), permitting intra- and inter-laboratory comparisons. Using this toolkit and commercial reagents, we optimized automated ELISAs on two different high throughput platforms to measure antibody responses to SARS-CoV-2 antigens. The assays were calibrated to a reference standard from the World Health Organization. We also automated a surrogate neutralization (sn)ELISA that measures inhibition of ACE2-Spike or -RBD interactions by antibodies using biotinylated ACE2. RESULTS: Our individual IgG-based ELISAs measure antibody levels in single-point measurements in reference to a standard antibody curve to accurately distinguish non-infected and infected individuals (area under the curve > 0.96 for each assay). Positivity thresholds can be established in individual assays using precision-recall analysis (e.g., by fixing the false positive rate), or more stringently, by scoring against the distribution of the means of negative samples across multiple assays performed over several months. For seroprevalence assessment (in a non-vaccinated cohort), classifying a sample as positive if antibodies were detected for at least 2 of the 3 antigens provided the highest specificity. In vaccinated cohorts, increases in anti-spike and -RBD (but not -N) antibodies are observed. Here, we present detailed protocols to perform these assays using either serum/plasma or dried blood spots both manually and on two automated platforms, and to express the results in international units to facilitate data harmonization and inter-study comparisons. We also demonstrate that the snELISA can be performed automatically at single points, increasing the scalability of this functional assay for large seroprevalence studies. INTERPRETATION: The ability to measure antibodies to three viral antigens and identify neutralizing antibodies capable of disrupting spike-ACE2 interactions in high-throughput assays enables large-scale analyses of humoral immune responses to SARS-CoV-2 infection and vaccination. The "Made-in-Canada" set of protein reagents, produced at the National Research Council of Canada are publicly available to enable the up-scaling of standardized serological assays, permitting nationwide data comparison and aggregation.

Prioritizing Ontario’s long-term care home (LTCH) residents for vaccination against severe acute respiratory syndrome coronavirus 2 has drastically reduced their disease burden; however, recent LTCH outbreaks of variants of concern (VOCs) have raised questions regarding their immune responses. In 198 residents, mRNA vaccine dose 1 elicited partial spike and receptor binding domain antibody responses, while the second elicited a response at least equivalent to convalescent individuals in most residents. Residents administered mRNA-1273 (Moderna) mounted stronger total and neutralizing antibody responses than those administered BNT162b2 (Pfizer-BioNTech). Two to four weeks after dose 2, residents (n= 119, median age 88) produced 4.8–6.3-fold fewer neutralizing antibodies than staff (n= 78; median age 47) against wild-type (with D614G) pseudotyped lentivirus, and residents administered BNT162b2 produced 3.89-fold fewer neutralizing antibodies than those who received mRNA-1273. These effects were exacerbated upon serum challenge with pseudotyped VOC spike, with up to 7.94-fold reductions in B.1.351 (Beta) neutralization. Cumulatively, weaker vaccine stimulation, age/comorbidities, and the VOC produced an ∼130-fold reduction in apparent neutralization titers in LTCH residents and 37.9% of BNT162b2-vaccinated residents had undetectable neutralizing antibodies to B.1.351. Continued immune response surveillance and additional vaccine doses may be required in this population with known vulnerabilities.

To compare sensitivity of specimens for COVID-19 diagnosis, we tested 151 nasopharyngeal/midturbinate swab pairs from 117 COVID-19 inpatients using reverse-transcriptase polymerase chain reaction (RT-PCR). Sensitivity was 94% for nasopharyngeal and 75% for midturbinate swabs (P = .0001). In 88 nasopharyngeal/midturbinate pairs with matched saliva, sensitivity was 86% for nasopharyngeal swabs and 88% for combined midturbinate swabs/saliva.

SummaryBackgroundThe aim of this prospective cohort study was to determine the burden of SARS-CoV-2 in air and on surfaces in rooms of patients hospitalized with COVID-19, and to identify patient characteristics associated with SARS-CoV-2 environmental contamination.MethodsNasopharyngeal swabs, surface, and air samples were collected from the rooms of 78 inpatients with COVID-19 at six acute care hospitals in Toronto from March to May 2020. Samples were tested for SARS-CoV-2 viral RNA and cultured to determine potential infectivity. Whole viral genomes were sequenced from nasopharyngeal and surface samples. Association between patient factors and detection of SARS-CoV-2 RNA in surface samples were investigated using a mixed-effects logistic regression model.FindingsSARS-CoV-2 RNA was detected from surfaces (125/474 samples; 42/78 patients) and air (3/146 samples; 3/45 patients) in COVID-19 patient rooms; 17% (6/36) of surface samples from three patients yielded viable virus. Viral sequences from nasopharyngeal and surface samples clustered by patient.Multivariable analysis indicated hypoxia at admission, a PCR-positive nasopharyngeal swab with a cycle threshold of ≤30 on or after surface sampling date, higher Charlson co-morbidity score, and shorter time from onset of illness to sample date were significantly associated with detection of SARS-CoV-2 RNA in surface samples.InterpretationThe infrequent recovery of infectious SARS-CoV-2 virus from the environment suggests that the risk to healthcare workers from air and near-patient surfaces in acute care hospital wards is likely limited. Surface contamination was greater when patients were earlier in their course of illness and in those with hypoxia, multiple co-morbidities, and higher SARS-CoV-2 RNA concentration in NP swabs. Our results suggest that air and surfaces may pose limited risk a few days after admission to acute care hospitals.

SARS-CoV-2 is a novel respiratory virus that has quickly spread across the globe. The virus uses a protein called Spike and its associated receptor binding domain (RBD) to interact with angiotensin converting enzyme-2 (ACE-2) on the surface of epithelial cells in the respiratory tract. Although a definite correlate of protection against COVID-19 has yet to emerge, many studies have quantified anti-Spike and anti-RBD IgG antibody (Ab) levels, as well as neutralizing Ab in the blood to ascertain immunity. This approach misses out on Ab that are produced in the upper respiratory tract (URT) mucosa – the site of viral encounter. Whether intramuscularly (i.m.) administered COVID-19 vaccines can promote immunity in the mucosa is not well understood. We recently completed a study where we showed that anti-Spike/RBD IgG could be detected in the saliva following i.m. vaccination with either two doses of mRNA vaccines (Pfizer or Moderna) or with a heterologous dosing of Astra Zeneca followed by an mRNA vaccine. Administration of a second dose of mRNA boosted the IgG but not IgA response, with only 30% of participants remaining positive for IgA at this timepoint. At 6 months post-dose 2, these participants had diminished anti-Spike/RBD IgG levels, although secretory component associated anti-Spike Ab were more stable. Examining two prospective cohorts we found that participants who experienced breakthrough infections with SARS-CoV-2 had lower levels of vaccine-induced serum anti-Spike/RBD IgA at 2–4 weeks post-dose 2 compared to participants who did not experience an infection, whereas IgG levels were comparable between groups. These data suggest that COVID-19 vaccines that elicit a durable IgA response may have utility in preventing infection. We received funding support from CIHR (Fund #15992), a COVID-19 Immunity Task force grant, an “Ontario Together” province of Ontario grant, a CIHR team grant to CoVARR-Net, a Donation from the Royal Bank of Canada (RBC) and a donation from the Krembil Foundation to the Sinai Health System Foundation.

Saliva is an alternative biofluid to serum for detecting and monitoring IgG to SARS-CoV-2 spike and RBD antigens in COVID-19., While the antibody response to SARS-CoV-2 has been extensively studied in blood, relatively little is known about the antibody response in saliva and its relationship to systemic antibody levels. Here, we profiled by enzyme-linked immunosorbent assays (ELISAs) IgG, IgA and IgM responses to the SARS-CoV-2 spike protein (full length trimer) and its receptor-binding domain (RBD) in serum and saliva of acute and convalescent patients with laboratory-diagnosed COVID-19 ranging from 3–115 days post-symptom onset (PSO), compared to negative controls. Anti-SARS-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16–30 days PSO. Longitudinal analysis revealed that anti-SARS-CoV-2 IgA and IgM antibodies rapidly decayed, while IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. Lastly, IgG, IgM and to a lesser extent IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that serum and saliva IgG antibodies to SARS-CoV-2 are maintained in the majority of COVID-19 patients for at least 3 months PSO. IgG responses in saliva may serve as a surrogate measure of systemic immunity to SARS-CoV-2 based on their correlation with serum IgG responses.

While the antibody response to SARS-CoV-2 has been extensively studied in blood, relatively little is known about the mucosal immune response and its relationship to systemic antibody levels. Since SARS-CoV-2 initially replicates in the upper airway, the antibody response in the oral cavity is likely an important parameter that influences the course of infection, but how it correlates to the antibody response in serum is not known. Here, we profile by enzyme linked immunosorbent assays (ELISAs) IgG, IgA and IgM responses to the SARS-CoV-2 spike protein (full length trimer) and its receptor binding domain (RBD) in serum (n=496) and saliva (n=90) of acute and convalescent patients with laboratory-diagnosed COVID-19 ranging from 3–115 days post-symptom onset (PSO), compared to negative controls. Anti-CoV-2 antibody responses were readily detected in serum and saliva, with peak IgG levels attained by 16–30 days PSO. Whereas anti-CoV-2 IgA and IgM antibodies rapidly decayed, IgG antibodies remained relatively stable up to 105 days PSO in both biofluids. In a surrogate neutralization ELISA (snELISA), neutralization activity peaks by 31–45 days PSO and slowly declines, though a clear drop is detected at the last blood draw (105–115 days PSO). Lastly, IgG, IgM and to a lesser extent IgA responses to spike and RBD in the serum positively correlated with matched saliva samples. This study confirms that systemic and mucosal humoral IgG antibodies are maintained in the majority of COVID-19 patients for at least 3 months PSO. Based on their correlation with each other, IgG responses in saliva may serve as a surrogate measure of systemic immunity.One Sentence SummaryIn this manuscript, we report evidence for sustained SARS-CoV-2-specific IgG and transient IgA and IgM responses both at the site of infection (mucosae) and systemically in COVID-19 patients over 3 months and suggest that saliva could be used as an alternative biofluid for monitoring IgG to SARS-CoV-2 spike and RBD antigens.

Background Data on household transmission of carbapenemase-producing Enterobacterales (CPE) remain limited. We studied risk of CPE household co-colonization and transmission in Ontario, Canada. Methods We enrolled CPE index cases (identified via population-based surveillance from January 2015 to October 2018) and their household contacts. At months 0, 3, 6, 9, and 12, participants provided rectal and groin swabs. Swabs were cultured for CPE until September 2017, when direct polymerase chain reaction (PCR; with culture of specimens if a carbapenemase gene was detected) replaced culture. CPE risk factor data were collected by interview and combined with isolate whole-genome sequencing to determine likelihood of household transmission. Risk factors for household contact colonization were explored using a multivariable logistic regression model with generalized estimating equations. Results Ninety-five households with 177 household contacts participated. Sixteen (9%) household contacts in 16 (17%) households were CPE-colonized. Household transmission was confirmed in 3/177 (2%) cases, probable in 2/177 (1%), possible in 9/177 (5%), and unlikely in 2/177 (1%). Household contacts were more likely to be colonized if they were the index case’s spouse (odds ratio [OR], 6.17; 95% confidence interval [CI], 1.05–36.35), if their index case remained CPE-colonized at household enrollment (OR, 7.00; 95% CI, 1.92–25.49), or if they had at least 1 set of specimens processed after direct PCR was introduced (OR, 6.46; 95% CI, 1.52–27.40). Conclusions Nine percent of household contacts were CPE-colonized; 3% were a result of household transmission. Hospitals may consider admission screening for patients known to have CPE-colonized household contacts.

We enrolled 53 consecutive in-patients with COVID-19 at six hospitals in Toronto, Canada, and tested one nasopharyngeal swab/saliva sample pair from each patient for SARS-CoV-2. Overall, sensitivity was 89% for nasopharyngeal swabs and 77% for saliva (p=NS); difference in sensitivity was greatest for sample pairs collected later in illness.

In myeloid malignancies, presence of 'multi-hit' TP53 mutations is associated with lack of response to conventional therapy and dismal outcomes, particularly when found in combination with a complex karyotype. Therefore, it is crucial to understand the biological basis of TP53-mutant driven clonal evolution, suppression of antecedent clones and eventual disease transformation to inform the development of more effective therapies. Myeloproliferative neoplasms (MPN) represent an ideal tractable disease model to study this process, as progression to secondary acute myeloid leukemia (sAML) frequently occurs through the acquisition of TP53 missense mutations. To characterize tumor phylogenies, cellular hierarchies and molecular features of TP53-driven transformation, we performed single-cell multi-omic TARGET-seq analysis (PMID: 33377019 & 30765193) of 22116 hematopoietic stem and progenitor cells (HSPCs) from 35 donors and 40 timepoints (controls, MPN in chronic phase, pre-AML and TP53-mutated sAML; Figure1a). TARGET-seq uniquely enables single-cell mutation analysis with allelic resolution with parallel transcriptomic and cell-surface proteomic readouts. We invariably identified convergent clonal evolution leading to complete loss of TP53 wild-type alleles upon transformation, including parallel evolution of separate TP53 "multi-hit" subclones in the same patient (n=4/14) and JAK2-negative progression (n=2/14). Complex clonal evolution driven by chromosomal abnormalities (CAs) was present in all patients and TP53 multi-hit HSPCs without CAs were rarely observed. Subclones with recurrent CA such as monosomy 7 showed upregulation of RAS-associated transcription and preferentially expanded in xenograft models. Together, these data indicate that TP53 missense mutation, loss of TP53 wild-type allele and cytogenetic evolution are collectively required for leukemic stem cell (LSC) expansion. Integrated transcriptomic analysis of sAML samples (Figure1b) revealed three major populations: (1) a TP53-mutant cluster (Figure1c) characterized by an erythroid signature (e.g. KLF1, GATA1, GYPA; an unexpected finding as no cases showed diagnostic features of erythroid leukemia), (2) an LSC TP53-mutant cluster (Figure1d) and (3) a TP53-WT preleukemic cluster (Figure1e). The LSC cluster showed dysregulation of key stem cell regulators, from which we derived a novel 48-gene LSC score with prognostic impact in an independent AML cohort (HR=3.13; Figure1f). Importantly, this score was predictive of outcome irrespective of TP53 status for both de novo and sAML, demonstrating its broader potential clinical utility. TARGET-seq analysis uniquely allowed us to characterize rare TP53-WT preleukemic cells (preLSCs), which were almost exclusively confined to the immunophenotypic lineage-CD34+CD38-CD90+CD45RA- HSC compartment. PreLSC from sAML samples presented increased stemness, increased quiescence, aberrant inflammatory signaling and differentiation defects (Figure1g) as compared to HSCs from normal or MPN donors, both at the transcriptional and functional levels through in vitro long-term and short-term cultures. This indicates cell-extrinsic suppression of residual TP53-WT hematopoiesis. Longitudinal analysis of TP53-heterozygous mutant HSPCs at different stages of disease evolution (Figure1a) revealed that aberrant inflammatory signalling (e.g. BST2, IFITM1, IFITM3) in the genetic ancestors of TP53 "multi-hit" LSCs, but not the presence of TP53-mutations alone, was predictive of subsequent transformation. In a mouse model system, TP53-mutant cells challenged with sustained inflammatory stimuli acquired a mean 3-fold competitive advantage in WT: TP53 R172H/+chimeras. This indicates that pro-inflammatory cues from the tumour microenvironment promote fitness advantage of TP53-mutant cells whilst supressing antecedent clones. In summary, we present a comprehensive single-cell multi-omic analysis of the genetic, cellular and molecular landscape of TP53-mediated transformation, providing unique insights into the evolution of chronic hematological malignancies towards an aggressive acute leukemia (Figure1h). Since TP53 is the most commonly mutated gene in human cancer, we anticipate these findings will be of broader relevance to many other cancer types. Figure 1 Figure 1. Disclosures Kretzschmar: Vanadis Diagnostics, a PerkinElmer company.: Current Employment. Drummond: BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; CTI: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Harrison: Geron: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Galacteo: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keros: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sierra Oncology: Honoraria; Constellation Pharmaceuticals: Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AOP Orphan Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte Corporation: Speakers Bureau; Promedior: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead Sciences: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Mead: Abbvie: Consultancy, Honoraria; Celgene/BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Speakers Bureau.

Background The hospital water environment is a CPE reservoir, and transmission of CPE from drains to patients is a risk. Methods We cultured sink and shower drains in patient rooms and communal shower rooms that were exposed to inpatients with CPE colonization/infection from October 2007 to December 2017 at 10 hospitals. We compared patient room drain CPE to prior room occupant CPE using Illumina and MinION whole-genome sequencing. Results Three-hundred and ten inpatients exposed 1,209 drains, of which 53 (4%) yielded 62 CPE isolates at 7 (70%) hospitals. Compared to room occupant CPE isolates, drain CPE isolates were more likely Enterobacter spp. (6, 10% vs. 25, 51%, p< 0.0001) or KPC-producers (9, 15% vs. 23, 47%, p=0.0002). Of the 49 CPE isolates in patient room drains, 4 (8%) were linked to a prior room occupant (Table), 24 (49%) had the same carbapenemase as a prior room occupant but isolates/carbapenemase gene-containing plasmids that were unrelated, and 21 (43%) did not share a carbapenemase with a prior room occupant. The 4 drains linked to prior room occupants were likely contaminated by these room occupants, who were CPE-colonized prior to drain exposure. Despite few links between drain and room occupant CPE, there were 10 isolates harbouring related blaNDM-1-containing IncHI2A/HI2-type plasmids in 8 rooms on two units at one hospital. Nine of these were Enterobacter hormaechei ST66 isolates that were 0 to 6 SNVs apart and one was a Klebsiella oxytoca STnovel isolate. Table. Four patient room drain CPE isolates (D1b, D4, D5, D12) and isolates from prior room occupants that they were related to by whole-genome sequencing. Conclusion It was uncommon for drain CPE to be linked to prior patient exposure. This suggests contamination of most drains by undetected colonized patients and a need for more aggressive patient screening in our hospitals. This may also suggest retrograde (drain-to-drain) transmission, especially considering the 10 isolate drain cluster at one hospital. Reasons for the preponderance of Enterobacter spp. in drains requires further study. Disclosures Allison McGeer, MD, FRCPC, GlaxoSmithKline (Advisor or Review Panel member, Research Grant or Support)Merck (Advisor or Review Panel member, Research Grant or Support)Pfizer (Research Grant or Support)

Background Carbapenemase-producing Enterobacteriaceae (CPE) are a global threat. Risk of transmission of CPE in households remains poorly understood Methods Population-based surveillance for CPE colonization/infection is conducted in Toronto/Peel Region, Canada. In households with ≥1 consenting household contact (HC), groin, rectal swabs and urine samples are submitted every 3 months for both IC and HC until the IC has three consecutive negative swab sets. Swabs/urines are incubated overnight in BHI, direct PCR for carbapenemase genes is performed; specimens positive for PCR are then cultured. Results Eighty-five households and 150 HC have been enrolled. Most common species/gene combinations in IC are: E. coli/NDM (33), E. coli/OXA48 (15), Klebsiella spp./NDM (11). HCs have a median of eight swabs (range 2–14). 12 (8%) HCs were colonized with CPE (median 1.5 pos samples, range 1–8). IC and HC had same gene in 11(92%) cases, and same species/gene in seven (58%) cases. NDM+OXA48 ICs were more likely to have CPE colonized HC, see table. CPE colonized HC were older, more likely to be the IC’s spouse (OR 32, 95% CI 4–260), and more likely to have travelled outside Canada (OR 9.7, 95% CI 1.2–78). Conclusion HC colonization with CPE is uncommon, but not rare, and may be associated with either household transmission, or co-exposure of HC and IC via travel. Spouses are most often colonized. Characteristic CPE Positive N = 12 CPE Negative N = 138 P-Value Gender (n, % male) 3 (25%) 53 (38%) 0.27 Median age (range) 70y(24-89) 42y (4-98) 0.005 Chronic illness 6 (50%) 35 (25%) 0.08 Relationship to IC Spouse 11(92%) 35 (25%) 3 months 7/11(64%) 32/61(52%) 0.72 >6 months 6/10(60%) 23/53(43%) 0.49 Disclosures S. Poutanen, MERCK: Scientific Advisor, Speaker honorarium; COPAN: Speaker(but not part of a bureau), Travel reimbursement; Accelerate Diagnostics: Investigator, Research support; Bio-Rad: Investigator, Research support; bioMérieux: Investigator, Research support.

Background Hospital wastewater environments are recognized as reservoirs for multi-drug-resistant bacteria, and sink drains in ICUs have been implicated in numerous outbreaks. The mechanism of pathogen transmission to patients, and the best approach to risk mitigation remains unclear. We tested a new copper alloy sink drain for its effect on detection of gammaproteobacteria in sink drains and adjacent aerosols. Methods We randomized 90 sinks in 76 ICU rooms/bedspaces in 7 ICUs to new standard chrome or copper alloy drains. We sampled sinks on 4 occasions over 4 months. Drain tailpieces were sampled using cotton swabs of 140 cm2 of the interior surface, inserted into 1mL of Dey-Engley neutralizing broth, and cultured semi-quantitatively for gammaproteobacteria on Mac3CV. 850L samples of air adjacent to sinks were obtained by impaction onto Mac3CV. Faucet swabs were also cultured. Multivariable analysis adjusting for factors associated with growth in air and drains used conditional logistic regression, GEE with an exchangeable correlation matrix, a robust estimate of variance, negative binomial distribution and log link function. Results Gammaproteobacteria were detected in 247/424 (58%) tailpiece swabs, 137/456 (30%) air samples, and 31/456 (7%) faucet swabs. In multivariable analysis, growth was less likely from air adjacent to sinks with copper vs. chrome drains [IRR 0.50 (95% CI 0.35, 0.73), P < 0.0001], with reduced effect size observed when drain growth was included in the model [IRR 0.64 (95% CI 0.43, 0.94)], P = 0.025]. Growth in air was more likely when drain growth was 1–899 cfu/cm2 [IRR 2.38 (95% CI 1.46, 3.88), P = 0.001] or ≥900 cfu/cm2 [IRR 3.55 (95% CI 1.87, 6.86), P < 0.001] vs. no growth. Tailpiece swab growth was more likely if rooms were occupied compared with empty [IRR 1.85 (95% CI 1.25, 2.76), P = 0.002], and less likely from copper drains compared with swabs from chrome drains [IRR 0.51 (95% CI 0.47, 0.75), P ≤ 0.001]. Conclusion Sinks with new copper drains are less likely to have detectable gammaproteobacteria in adjacent air when compared with standard chrome drains, and results suggest this is mediated through reduced bacterial growth in the drains. Ongoing study is needed to determine whether this influences patient risk for hospital-acquired infection. Disclosures All authors: No reported disclosures.

Background Hospital drains may be a source of CPE in patients. We determined prevalence of and risk factors for CPE contamination of hospital drains exposed to patients with CPE colonization/infection. Methods We cultured hand hygiene and patient use sink as well as tub/shower drains exposed to 310 inpatients colonized/infected with CPE in 10 Ontario hospitals. A multi-level logistic regression model was fitted to determine whether type of drain/room/unit was associated with CPE drain contamination. Drain and room occupant CPE isolates underwent Illumina whole-genome and MinION sequencing. Single nucleotide variant (SNV) phlogenomic analyses and plasmid characterization were performed. Results 53/ Of the 1,209 drains, 53 (4%) at 7 (70%) hospitals yielded CPE. Patient room shower drains were significantly more likely to yield CPE than hand hygiene sink (OR 3.35, 95% CI 1.61–6.97) and patient use sink (OR 10.89, 95% CI 3.62–32.80) drains. Hand hygiene sink drains were significantly more likely to yield CPE than patient use sink drains (OR 3.26, 95% CI 1.05–10.13). 8 (15%) drain isolates matched the room occupant CPE gene/species; 24 (44%) matched the gene but not species, and 23 (42%) matched neither gene nor species. Among 13 drain/11 room occupant pairs with molecular comparisons to date, only 1/13 (8%) drain isolates matched the respective room occupant carbapenemase allele and replicon harboring the carbapenemase gene (IncN replicon harboring blaKPC-3). In addition, one drain isolate had a plasmid highly related to plasmids of 2 isolates from a patient occupying a room in an adjacent unit (IncN3 replicons harboring blaKPC-2). At another hospital, all 6 drain isolates were located on one unit and had an IncHI2A/HI2/TrfA replicon harboring blaNDM-1; 5 of these were E. cloacae ST66, with 0–3 SNV differences observed between isolates. Conclusion Different drain types have different risks of CPE contamination. In our setting, most drain contamination was not caused by recognized room occupants. Further investigation is needed to understand the sources of hospital drain CPE contamination. Disclosures All authors: No reported disclosures.

Background We aimed to assess the risk of subsequent infection among patients colonized by CPE. Methods The Toronto Invasive Bacterial Diseases Network (TIBDN) has conducted population-based surveillance for CPE colonization/infection in Toronto and Peel region, Ontario, Canada, since CPE were first identified (2007). All laboratories report all CPE isolates to TIBDN. Clinical data are collected via patient interview and hospital chart review. Initially colonized patients are followed for 5y; subsequent CPE infection is defined as an episode with onset >3 days after initial detection of CPE colonization that meets National Healthcare Safety Network criteria for infection with a clinical isolate of CPE. Results From 2007 to 2018, 790 persons with CPE colonization/infection were identified. Among 364 cases colonized at identification, 42 (12%) subsequently had at least one clinical isolate, and 23 (6%) had an infection: 8 with bacteremia (primary or secondary), 7 UTI, 5 pneumonia, and 3 other. The median time from identification of colonization to infection was 21 days (IQR 7–38), with a probability of developing an infection of 7% at 3 months, and 18% by 3 years (figure). In 305 cases with data available to date, older persons, those admitted to the ICU, and those with current/recent invasive medical devices were more likely to develop infection (table). Gender, underlying conditions and other procedures were not associated with risk of infection. There was a trend to infections being more likely in patients colonized with K. pneumoniae (52% vs. 35%, P = 0.13). Conclusion The risk of subsequent infection in our cohort was 18%, with highest risk in the first 3 months; most infections occurred in patients requiring intensive care unit admission and invasive medical devices. Disclosures All authors: No reported disclosures.

Background This study evaluated AXDX (uses FISH/real-time microscopy to obtain ID/AST direct from +BC in

Background The spread of CPE is an increasing global threat to patient safety. We describe the introduction and evolution of CPE in south-central Ontario, Canada. Methods The Toronto Invasive Bacterial Diseases Network has performed population based surveillance for CPE in metropolitan Toronto and Peel region from first identified isolates in 2007. All laboratories test/refer all carbapenem non-susceptible Enterobacterial isolates for PCR testing for carbapenemases. Demographic and medical data and travel history are collected from chart review and patient/physician interview. Results Since 2007, 659 patients have been identified as colonized/infected with CPE; 362, 57%) have at least one clinical isolate. Annual incidence has increased from 0 in 2006 to 1.3 per 100,000 in 2016/17 (Figure 1). First bacteremia occurred in 2010, the incidence in 2017 was 0.14 per 100,000 population. 388 (59%) patients were male, median age was 70 years (range 3 months–100 years). Most common genes among first isolates were NDM (306, 46%), OX48 (149, 23%), KPC (122, 19%). Most common species were K. pneumoniae (268, 41%) and E. coli (259, 39%). Over time, second species/same gene were identified in 113 (16%) patients. In addition, 34/xxx patients with isolates with NDM and/or OXA-48 subsequently had a second isolate with a different gene/gene combination. Of 518 patients whose travel and hospitalization history are available, patients with VIM were less likely than other patients to have a foreign hospitalization or travel history (9/28 vs. 341/490, P < 0.0001). Patients with KPC were more likely to have a hospitalization history outside Canada and the Indian subcontinent (25/70, 36%), in Canada (47/164,29%) than to have no hospitalization in the last year (13/93, 14%), or a history of hospitalization in the Indian subcontinent (2/191, 1%) (P < 0.001). The number of incident patients with different hospitalization and travel history over time is shown in Figure 2. Conclusion CPE is increasingly recognized in southern Ontario, both in patients with a history of exposure in healthcare in other countries, and to healthcare in Canada. Intensification of control programs is urgently needed. Disclosures S. Poutanen, MERCK: Scientific Advisor, Speaker honorarium. COPAN: Speaker(but not part of a bureau), Travel reimbursement. Accelerate Diagnostics: Investigator, Research support. Bio-Rad: Investigator, Research support. bioMérieux: Investigator, Research support.

Background Hospital waste water systems are an emerging reservoir for CPE. We aimed to describe the prevalence of CPE in hospital drains in southern Ontario, where patients are rarely colonized/infected by CPE. Methods Ten Ontario hospitals identified rooms occupied by CPE+ inpatients from 2007 to 2017. Drain swabs from patient rooms and communal shower rooms were inoculated into BHI + 10% Dey-Engley neutralizing broth and incubated overnight, then PCR on enriched broth for carbapenemase genes as well as culture on McPOD/McMEM were performed. Results Over 10 years in 10 hospitals, 343 CPE+ inpatients exposed 1,205 drains (852 sinks, 353 bathtub/shower drains) in 501 patient rooms and 71 communal shower rooms. 53 (4%) drains in 40 (8%) patient rooms and 10 (14%) communal shower rooms were CPE+ by PCR and culture. CPE+ drains were from 15/475 (3%) hand hygiene sinks, 4/352 (1%) bathroom sinks, 23/272 (9%) bathtubs/showers, and 11/81 (13.6%) communal showers. Eleven (21%) of the CPE+ drains contained 31 CPE gene/species combinations. Patient room drain CPE gene/species combinations are shown in Figure 1: eight (15%) matched the CPE gene/species combination of a room occupant, 23 (43%) matched gene only, and 23 (43%) did not match. 54% of drain isolates were Enterobacter spp. but 9% of patient isolates were Enterobacter spp. There were 155 (13%) additional drains with one or more genes detected by PCR but not culture; 94 (61%) contained VIM (88 bathtub, one bathroom sink, and five hand hygiene sink drains), 33 GES, 17 OXA, 16 IMP, 10 KPC, and five NDM. There were six drains where one or more genes were detected by culture but not PCR; four (67%) were bathtub/shower drains containing an OXA, one bathtub/shower drain containing an NDM, and one hand hygiene sink drain containing a KPC. Conclusion Hospital drains may become a reservoir for CPE, which may persist for years. Sensitivity of PCR and culture for detection of CPE and CP organisms may differ. The presence of “unmatched” drains suggests undetected patient colonization. Risk of transmission from drains to room occupants requires investigation. Disclosures All authors: No reported disclosures.

Background AXDX reports ID/AST in