Additional diagnoses of Echinococcus multilocularis in eastern chipmunks (Tamias striatus) from southern Ontario - results from ongoing surveillance for E. multilocularis in intermediate hosts in Ontario, Canada.

Echinococcus multilocularis, a cestode with zoonotic potential, is now known to have a high prevalence in wild canid definitive hosts of southern Ontario. The distribution of E. multilocularis across this region in red foxes (Vulpes vulpes) and coyotes (Canis latrans) is widespread yet heterogenous. In contrast, confirmed diagnoses of E. multilocularis in wild free-ranging intermediate hosts within Ontario are currently limited to a single eastern chipmunk (Tamias striatus). These findings prompted ongoing surveillance efforts in intermediate host species, primarily rodents. Our report describes the results of passive surveillance through wildlife carcass submissions to the Canadian Wildlife Health Cooperative (CWHC) and targeted active sampling of small mammal species from 2018 to 2023; a second and third eastern chipmunk were found to be infected with E. multilocularis. However, these were the only occurrences from surveillance efforts which collectively totaled 510 rodents and other small mammals. Continued surveillance for E. multilocularis in intermediate hosts is of high importance in light of the recent emergence of this parasite in Ontario.

Inhalation of ACE2 as a therapeutic target on sex-bias differences in SARS-CoV-2 infection and variant of concern.

Despite similar infection rates, COVID-19 has resulted in more deaths in men than women. To understand the underlying mechanisms behind this sex-biased difference in disease severity, we infected K18-human angiotensin converting enzyme 2 (ACE2) mice of both sexes with SARS-CoV-2. Our study revealed a unique protein expression profile in the lung microenvironment of female mice. As a result, they were less vulnerable to severe infection, with higher ACE2 expression and a higher estrogen receptor α (ERα)/androgen receptor (AR) ratio that led to increased antiviral factor levels. In male mice, inhaling recombinant ACE2 neutralized the virus and maintained the ERα/AR ratio, thereby protecting the lungs. Our findings suggest that inhaling recombinant ACE2 could serve as a decoy receptor against SARS-CoV-2 and protect male mice by offsetting ERα-associated protective mechanisms. Additionally, our study supports the potential effectiveness of recombinant ACE2 therapy in human lung organoids infected with the Delta variant.

Identification and differential usage of a host metalloproteinase entry pathway by SARS-CoV-2 Delta and Omicron.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike glycoprotein (S) binds to angiotensin-converting enzyme 2 (ACE2) to mediate membrane fusion via two distinct pathways: 1) a surface, serine protease-dependent or 2) an endosomal, cysteine protease-dependent pathway. In this study, we found that SARS-CoV-2 S has a wider protease usage and can also be activated by TMPRSS13 and matrix metalloproteinases (MMPs). We found that MMP-2 and MMP-9 played roles in SARS-CoV-2 S cell-cell fusion and TMPRSS2- and cathepsin-independent viral entry in cells expressing high MMP levels. MMP-dependent viral entry required cleavage at the S1/S2 junction in viral producer cells, and differential processing of variants of concern S dictated its usage; the efficiently processed Delta S preferred metalloproteinase-dependent entry when available, and less processed Omicron S was unable to us metalloproteinases for entry. As MMP-2/9 are released during inflammation, they may play roles in S-mediated cytopathic effects, tropism, and disease outcome.

Immunogenicity of convalescent and vaccinated sera against clinical isolates of ancestral SARS-CoV-2, Beta, Delta, and Omicron variants.

Background: SARS-CoV-2 Omicron variant of concern (VOC) has evolved multiple mutations within the spike protein, raising concerns of increased antibody evasion. In this study, we assessed the neutralization potential of COVID-19 convalescent sera and sera from vaccinated individuals against ancestral SARS-CoV-2 and VOCs. Methods: The neutralizing activity of sera from 65 coronavirus disease (COVID-19) vaccine recipients and convalescent individuals against clinical isolates of ancestral SARS-CoV-2 and Beta, Delta, and Omicron VOCs was assessed using a micro-neutralization assay. Findings: Convalescent sera from unvaccinated individuals infected by the ancestral virus demonstrated reduced neutralization against Beta and Omicron VOCs. Sera from individuals that received three doses of the Pfizer or Moderna vaccines demonstrated reduced neutralization of the Omicron variant relative to ancestral SARS-CoV-2. Sera from individuals that were naturally infected with ancestral SARS-CoV-2 and subsequently received two doses of the Pfizer vaccine induced significantly higher neutralizing antibody levels against ancestral virus and all VOCs. Infection alone, either with ancestral SARS-CoV-2 or the Delta variant, was not sufficient to induce high neutralizing antibody titers against Omicron. Conclusions: In summary, we demonstrate that convalescent and vaccinated sera display varying levels of SARS-CoV-2 VOC neutralization. Data from this study will inform booster vaccination strategies against SARS-CoV-2 VOCs. Funding: This research was funded by the Canadian Institutes of Health Research (CIHR). VIDO receives operational funding from the Government of Saskatchewan through Innovation Saskatchewan and the Ministry of Agriculture and from the Canada Foundation for Innovation through the Major Science Initiatives for its CL3 facility.

BCG vaccination provides protection against IAV but not SARS-CoV-2.

Since the vast majority of species solely rely on innate immunity for host defense, it stands to reason that a critical evolutionary trait like immunological memory evolved in this primitive branch of our immune system. There is ample evidence that vaccines such as bacillus Calmette-Guérin (BCG) induce protective innate immune memory responses (trained immunity) against heterologous pathogens. Here we show that while BCG vaccination significantly reduces morbidity and mortality against influenza A virus (IAV), it fails to provide protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). In contrast to IAV, SARS-CoV-2 infection leads to unique pulmonary vasculature damage facilitating viral dissemination to other organs, including the bone marrow (BM), a central site for BCG-mediated trained immunity. Finally, monocytes from BCG-vaccinated individuals mount an efficient cytokine response to IAV infection, while this response is minimal following SARS-CoV-2. Collectively, our data suggest that the protective capacity of BCG vaccination is contingent on viral pathogenesis and tissue tropism.

Intranasal HD-Ad vaccine protects the upper and lower respiratory tracts of hACE2 mice against SARS-CoV-2.

BACKGROUND: The ongoing COVID-19 pandemic has resulted in 185 million recorded cases and over 4 million deaths worldwide. Several COVID-19 vaccines have been approved for emergency use in humans and are being used in many countries. However, all the approved vaccines are administered by intramuscular injection and this may not prevent upper airway infection or viral transmission. RESULTS: Here, we describe a novel, intranasally delivered COVID-19 vaccine based on a helper-dependent adenoviral (HD-Ad) vector. The vaccine (HD-Ad_RBD) produces a soluble secreted form of the receptor binding domain (RBD) of the SARS-CoV-2 spike protein and we show it induced robust mucosal and systemic immunity. Moreover, intranasal immunization of K18-hACE2 mice with HD-Ad_RBD using a prime-boost regimen, resulted in complete protection of the upper respiratory tract against SARS-CoV-2 infection. CONCLUSION: Our approaches provide a powerful platform for constructing highly effective vaccines targeting SARS-CoV-2 and its emerging variants.

Burden of noninfluenza respiratory viral infections in adults admitted to hospital: analysis of a multiyear Canadian surveillance cohort from 2 centres.

BACKGROUND: Data on the outcomes of noninfluenza respiratory virus (NIRV) infections among hospitalized adults are lacking. We aimed to study the burden, severity and outcomes of NIRV infections in this population. METHODS: We analyzed pooled patient data from 2 hospital-based respiratory virus surveillance cohorts in 2 regions of Canada during 3 consecutive seasons (2015/16, 2016/17, 2017/18; n = 2119). We included patients aged ≥ 18 years who developed influenza-like illness or pneumonia and were hospitalized for management. We included patients confirmed positive for ≥ 1 virus by multiplex polymerase chain reaction assays (respiratory syncytial virus [RSV], human rhinovirus/enterovirus (hRV), human coronavirus (hCoV), metapneumovirus, parainfluenza virus, adenovirus, influenza viruses). We compared patient characteristics, clinical severity conventional outcomes (e.g., hospital length-of stay, 30-day mortality) and ordinal outcomes (5 levels: discharged, receiving convalescent care, acute ward or intensive care unit [ICU] care and death) for patients with NIRV infections and those with influenza. RESULTS: Among 2119 adults who were admitted to hospital, 1156 patients (54.6%) had NIRV infections (hRV 14.9%, RSV 12.9%, hCoV 8.2%) and 963 patients (45.4%) had influenza (n = 963). Patients with NIRVs were younger (mean 66.4 [standard deviation 20.4] yr), and more commonly had immunocompromising conditions (30.3%) and delay in diagnosis (median 4.0 [interquartile range (IQR) 2.0-7.0] days). Overall, 14.6% (12.4%-19.5%) of NIRV infections were acquired in hospital. Admission to ICU (18.2%, median 6.0 [IQR 3.0-13.0] d), hospital length-of-stay (median 5.0 [IQR 2.0-10.0] d) and 30-day mortality (8.4%; RSV 9.5%, hRV 6.6%, hCoV 9.2%) and the ordinal outcomes were similar for patients with NIRV infection and those with influenza. Age > 60 years, immunocompromised state and hospital-acquired viral infection were associated with worse outcomes. The estimated median cost per acute care admission was $6000 (IQR $2000-$16 000). INTERPRETATION: The burden of NIRV infection is substantial in adults admitted to hospital and associated outcomes may be as severe as for influenza, suggesting a need to prioritize therapeutics and vaccines for at-risk people.

Whole genome sequence of Corynebacterium kroppenstedtii isolated from a case of recurrent granulomatous mastitis.

We describe the case of a 33-year-old woman with recurrent granulomatous mastitis associated with Corynebacterium kroppenstedtii. This organism has been increasingly associated with granulomatous mastitis, specifically the cystic neutrophilic histopathologic variant, although currently there is a paucity both of reported cases and genomic sequence data. We highlight the challenges in the diagnosis and treatment of this entity, in particular focusing on the various methods of microbiologic identification, including MALDI-TOF, 16 s rRNA PCR and whole-genome sequencing.

The Thiazole-5-Carboxamide GPS491 Inhibits HIV-1, Adenovirus, and Coronavirus Replication by Altering RNA Processing/Accumulation.

Medicinal chemistry optimization of a previously described stilbene inhibitor of HIV-1, 5350150 (2-(2-(5-nitro-2-thienyl)vinyl)quinoline), led to the identification of the thiazole-5-carboxamide derivative (GPS491), which retained potent anti-HIV-1 activity with reduced toxicity. In this report, we demonstrate that the block of HIV-1 replication by GPS491 is accompanied by a drastic inhibition of viral gene expression (IC50 ~ 0.25 µM), and alterations in the production of unspliced, singly spliced, and multiply spliced HIV-1 RNAs. GPS491 also inhibited the replication of adenovirus and multiple coronaviruses. Low µM doses of GPS491 reduced adenovirus infectious yield ~1000 fold, altered virus early gene expression/viral E1A RNA processing, blocked viral DNA amplification, and inhibited late (hexon) gene expression. Loss of replication of multiple coronaviruses (229E, OC43, SARS-CoV2) upon GPS491 addition was associated with the inhibition of viral structural protein expression and the formation of virus particles. Consistent with the observed changes in viral RNA processing, GPS491 treatment induced selective alterations in the accumulation/phosphorylation/function of splicing regulatory SR proteins. Our study establishes that a compound that impacts the activity of cellular factors involved in RNA processing can prevent the replication of several viruses with minimal effect on cell viability.

A simple protein-based surrogate neutralization assay for SARS-CoV-2.

Most of the patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mount a humoral immune response to the virus within a few weeks of infection, but the duration of this response and how it correlates with clinical outcomes has not been completely characterized. Of particular importance is the identification of immune correlates of infection that would support public health decision-making on treatment approaches, vaccination strategies, and convalescent plasma therapy. While ELISA-based assays to detect and quantitate antibodies to SARS-CoV-2 in patient samples have been developed, the detection of neutralizing antibodies typically requires more demanding cell-based viral assays. Here, we present a safe and efficient protein-based assay for the detection of serum and plasma antibodies that block the interaction of the SARS-CoV-2 spike protein receptor binding domain (RBD) with its receptor, angiotensin-converting enzyme 2 (ACE2). The assay serves as a surrogate neutralization assay and is performed on the same platform and in parallel with an ELISA for the detection of antibodies against the RBD, enabling a direct comparison. The results obtained with our assay correlate with those of 2 viral-based assays, a plaque reduction neutralization test (PRNT) that uses live SARS-CoV-2 virus and a spike pseudotyped viral vector-based assay.

Characterization of Experimental and Clinical Bioaerosol Generation During Potential Aerosol-Generating Procedures.

BACKGROUND: During medical procedures with the potential to produce aerosols such as bronchoscopy, intubation, or CPR, health-care workers (HCWs) may be exposed to infectious bioaerosols. This scenario is of particular concern when high consequence pathogens such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are circulating. Thousands of HCWs have been infected with SARS-CoV-2. However, the determinants of aerosol generation during medical procedures and their relative risk to HCWs remain poorly characterized. RESEARCH QUESTION: The goal of this study was to characterize aerosols produced during airway intubation by using an uninfected translational animal model and in human subjects undergoing elective aerosol-generating procedures. The study also determined the particle size distribution of generated particles. STUDY DESIGN AND METHODS: Aerosol generation was measured during highly controlled experimental (pig) intubations (N = 16) and elective bronchoscopies in uninfected patients (N = 49) using an optical particle counter. Recovery of normal respiratory flora was used as a surrogate for pathogen dispersion. RESULTS: There was a small but significant (P = .03) decrease in 0.3 µm size particles during highly controlled pig intubations compared with baseline. The concentration of 1.0 µm and 5.0 µm aerosol particles did not significantly change, although oral bacteria were collected from the air. For elective patient bronchoscopies, there was a significant decrease in the generation of larger particles (1.0 µm and 5.0 µm) compared with baseline (P < .01); however, 18 of 39 (46%) patients showed increased aerosol production in 0.3 µm size particles, four of whom exhibited measurable increases. INTERPRETATION: Although the total amount of aerosols produced during intubation and bronchoscopy did not increase significantly relative to preprocedural levels, a small number of participants exhibited a measurable increase in submicron particle emission, meriting further research to delineate determinants of fine particle production during aerosol-generating procedures.

Severity of coronavirus respiratory tract infections in adults admitted to acute care in Toronto, Ontario.

BACKGROUND: The World Health Organization has highlighted the need for improved surveillance and understanding of the health burden imposed by non-influenza RNA respiratory viruses. Human coronaviruses (CoVs) are a major cause of respiratory and gastrointestinal tract infections with associated morbidity and mortality. OBJECTIVES: The objective of our study was to characterize the epidemiology of CoVs in our tertiary care centre, and identify clinical correlates of disease severity. STUDY DESIGN: A cross-sectional study was performed of 226 patients admitted with confirmed CoV respiratory tract infection between 2010 and 2016. Variables consistent with a severe disease burden were evaluated including symptoms, length of stay, intensive care unit (ICU) admission and mortality. RESULTS: CoVs represented 11.3% of all positive respiratory virus samples and OC43 was the most commonly identified CoV. The majority of infections were community-associated while 21.6% were considered nosocomial. The average length of stay was 11.8 days with 17.3% of patients requiring ICU admission and an all-cause mortality of 7%. In a multivariate model, female gender and smoking were associated with increased likelihood of admission to ICU or death. CONCLUSION: This study highlights the significant burden of CoVs and justifies the need for surveillance in the acute care setting.

Factors Associated with Choice and Success of One- Versus Two-Stage Revision Arthroplasty for Infected Hip and Knee Prostheses.

BACKGROUND: Prosthetic joint infections (PJI) of hip and knee arthroplasties are becoming increasingly common with an aging population and an increasing demand for these procedures. Despite attempts at standardization, medical and surgical approaches vary widely among practitioners. QUESTIONS/PURPOSES: We first sought to determine if there were specific factors associated with choice of one- versus two-stage revision. Then we investigated whether the type of revision approach influenced clinical treatment success. Finally, among two-stage revisions, we assessed if an antibiotic holiday prior to the second procedure affected clinical treatment success. METHODS: We retrospectively reviewed patients who had revision surgery for infection of a hip or knee arthroplasty between January 1, 2000, and December 31, 2013, at the Sunnybrook Health Sciences Centre and the Holland Orthopedic and Arthritic Centre. PJI cases were identified using the Ontario Joint Replacement Registry. Infection was defined by gross intraoperative evidence of infection, positive intraoperative culture(s), and/or sinus tract prior to operation. The primary outcome was treatment failure at 1 year after revision surgery based on requirement for further surgery, ongoing infection, and/or continuous suppressive antibiotics. RESULTS: Of 110 eligible patients identified, 35 patients had a one-stage and 75 patients had a two-stage revision. Choice of a one-stage approach was most influenced by particular surgeon preference and was more likely for hip revision versus knee revision (OR 3.39 (95%CI 1.85-6.23). There was no statistical difference in clinical treatment success rate between one-stage (33/35; 94.2% success) and two-stage revision (63/75; 84%; p = 0.13). Enterococcus spp. (21 versus 3%; p = 0.027) and Peptostreptococcus spp. (14 versus 1%; p = 0.042) were more common among clinical treatment failures than successes, with a trend towards the same for Staphylococcus aureus (29 versus 9%; p = 0.06). Additionally, treatment success was not influenced by whether the patient had an antibiotic holiday with a two-stage revision. CONCLUSION: Our findings confirm the uncertainty of surgical strategy for treatment of PJI in hip and knee arthroplasty. Superiority of one- versus two-stage revision and the value of antibiotic-free periods prior to definitive revision remain unclear. Large prospective studies or randomized controlled trials are needed to inform best practice for treatment of these complex clinical problems.

Patients, Here Comes More Nanotechnology.

We describe the current difference in reporting the performance of nanotechnology diagnostic devices between technologists and clinicians. This perspective specifies the "metrics" used to evaluate these devices and describes strategies to bridge the gap between these two communities in order to accelerate the translation from academic bench to the clinic. We use two recently published ACS Nano articles to highlight the evaluation of silicon nanowire and surface-enhanced Raman spectroscopy-breath diagnostic tests for patients afflicted with cancer and asthma. These studies represent some of the earliest studies of emerging nanotechnology devices utilizing clinical parameters to assess performance.

Mesenchymal stromal (stem) cell therapy fails to improve outcomes in experimental severe influenza.

RATIONALE: Severe influenza remains a major public health threat and is responsible for thousands of deaths annually. Increasing antiviral resistance and limited effectiveness of current therapies highlight the need for new approaches to influenza treatment. Extensive pre-clinical data have shown that mesenchymal stromal (stem) cell (MSC) therapy can induce anti-inflammatory effects and enhance repair of the injured lung. We hypothesized that MSC therapy would improve survival, dampen lung inflammation and decrease acute lung injury (ALI) in a murine model of severe influenza. METHODS: C57Bl/6 mice were infected with influenza A/PuertoRico/8/34 (mouse-adapted H1N1) or influenza A/Mexico/4108/2009 (swine-origin pandemic H1N1) and administered human or mouse MSCs via the tail vein, either pre- or post- infection. MSC efficacy was evaluated as both an independent and adjunctive treatment strategy in combination with the antiviral agent, oseltamivir. Weight loss and survival were monitored. Inflammatory cells, cytokine/chemokines (IFN-γ, CXCL10, CCL2 and CCL5) and markers of ALI (total protein and IgM), were measured in bronchoalveolar lavage fluid and lung parenchyma. RESULTS: Administration of murine MSCs or human MSCs in a prophylactic or therapeutic regimen failed to improve survival, decrease pulmonary inflammation/inflammatory cell counts or prevent ALI in influenza virus-infected mice. MSCs administered in combination with oseltamivir also failed to improve outcomes. CONCLUSIONS: Despite similarities in the clinical presentation and pathobiology of ALI and severe influenza, our findings suggest that MSC therapy may not be effective for prevention and/or treatment of acute severe influenza.

Immunomodulatory therapy for severe influenza.

Influenza A virus is a significant cause of morbidity and mortality worldwide. Severe influenza is recognized as a clinical syndrome, characterized by hyperinduction of proinflammatory cytokine production, otherwise known as hypercytokinemia or a 'cytokine storm'. Research focused on therapeutics to modulate influenza virus-induced inflammation is currently underway. In this review, we discuss the limitations of current antiviral drug treatment strategies, describe the influenza viral and host pathogenicity determinants, and present the evidence supporting the use of immunomodulatory therapy to target the host inflammatory response as a means to improve clinical outcome in severe influenza. We then review the experimental data on investigational immunomodulatory agents targeting the host inflammatory response in severe influenza, including anti-TNF therapy, statins, glucocorticoids, cyclooxygenase-2 inhibitors, macrolides, peroxisome proliferator-activated receptor agonists, AMP-activated protein kinase agonists and high mobility group box 1 antagonists. We then conclude with a rationale for the use of mesenchymal stromal (stem) cells and angiopoietin-1 therapy against deleterious influenza-induced host responses that mediate end-organ injury and dysfunction.

Aerosolized colistin for the treatment of nosocomial pneumonia due to multidrug-resistant Gram-negative bacteria in patients without cystic fibrosis.

The management challenges of patients with nosocomial pneumonia are great because of resistance among the responsible pathogens. In this issue of Critical Care, Argyris Michalopoulos and colleagues describe the use of inhaled colistin in the treatment of multidrug-resistant Gram-negative nosocomial pneumonia in a small group of patients. Although seven of eight patients who received nebulized colistin showed clinical improvement, some patients also received other active antibiotics. Microbiological eradication was demonstrated in only four of the eight patients. Serum levels of colistin were not measured. In addition, although adverse events were not documented in patients receiving colistin, formal assessments for bronchoconstriction and neurological toxicity were not completed in this retrospective study. Although resistance to colistin in Gram-negative organisms has not evolved, the risk of breakthrough infection with Gram-positive and inherently resistant Gram-negative bacteria remains a concern. The results of this limited study do, however, suggest that further studies examining the use of nebulized colistin are merited.