Autoantibodies against angiotensin-converting enzyme 2 (ACE2) after COVID-19 infection or vaccination

Autoantibodies against angiotensin-converting enzyme 2 (ACE2) are frequently reported in patients during coronavirus disease 2019 (COVID-19) with evidence for a pathogenic role in severe infection. However, little is known of the prevalence or clinical significance of ACE2 autoantibodies in late convalescence or following COVID-19 vaccination. In this study, we measured ACE2 autoantibodies in a cohort of 182 COVID-19 convalescent patients, 186 COVID-19 vaccine recipients, and 43 adolescents with post-mRNA vaccine myopericarditis using two ACE2 enzymatic immunoassays (EIAs). ACE2 IgM autoantibody EIA median optical densities (ODs) were lower in convalescent patients than pre-COVID-19 control samples with only 2/182 (1.1%) convalescents testing positive. Similarly, only 3/182 (1.6%) convalescent patients tested positive for ACE2 IgG, but patients with history of moderate-severe COVID-19 tended to have significantly higher median ODs than controls and mild COVID-19 patients. In contrast, ACE2 IgG antibodies were detected in 10/186 (5.4%) COVID-19 vaccine recipients after two doses of vaccination. Median ACE2 IgG EIA ODs of vaccine recipients were higher than controls irrespective of the vaccine platform used (inactivated or mRNA). ACE2 IgG ODs were not correlated with surrogate neutralizing antibody levels in vaccine recipients. ACE2 IgG levels peaked at day 56 post-first dose and declined within 12 months to baseline levels in vaccine recipients. Presence of ACE2 antibodies was not associated with adverse events following immunization including myopericarditis. One convalescent patient with ACE2 IgG developed Guillain-Barre syndrome, but causality was not established. ACE2 autoantibodies are observed in COVID-19 vaccine recipients and convalescent patients, but are likely innocuous.

Establishing Bipotential Human Lung Organoid Culture System and Differentiation to Generate Mature Alveolar and Airway Organoids

A robust in vitro model of the human respiratory epithelium, including the alveolar and the airway epithelium, is essential for understanding the biology and pathology of the human respiratory system. We previously described a protocol to derive human lung organoids from primary lung tissues. We now describe a protocol to induce bidirectional differentiation to generate mature alveolar or airway organoids. The lung organoids are consecutively expanded for over one year with high stability, while the differentiated alveolar and airway organoids morphologically and functionally simulate the human alveolar and airway epithelium to a near-physiological level. Thus, we establish a robust organoid culture system of the entire human respiratory epithelium, the first two-phase bipotential organoid culture system that enables long-term expansion and bidirectional differentiation of respiratory epithelial cells. The long-term expandable lung organoids and differentiated organoids generate a stable and renewable source of respiratory epithelial cells, enabling scientists to reconstruct and expand the human respiratory epithelium in culture dishes. The respiratory organoid system provides a unique and physiologically active in vitro model of the human respiratory epithelium for various applications, including studying respiratory viral infection, disease modeling, drug screening, and pre-clinical testing. Graphical abstract.

Subinhibitory Concentrations of Antibiotics Exacerbate Staphylococcal Infection by Inducing Bacterial Virulence

Antibiotics are widely used for the treatment of bacterial infections. However, injudicious use of antibiotics based on an empirical method may lead to the emergence of resistant strains. Despite appropriate administration of antibiotics, their concentrations may remain subinhibitory in the body, due to individual variations in tissue distribution and metabolism rates. This may promote bacterial virulence and complicate the treatment strategies. To investigate whether the administration of certain classes of antibiotics will induce bacterial virulence and worsen the infection under in vivo conditions. Different classes of antibiotics were tested in vitro for their ability to induce virulence in a methicillin-resistant S. aureus strain Mu3 and clinical isolates. Antibiotic-induced pathogenicity was assessed in vivo using mouse peritonitis and bacteremia models. In vitro, β-lactam antibiotics and tetracyclines induced the expression of multiple surface-associated virulence factors as well as the secretion of toxins. In peritonitis and bacteremia models, mice infected with MRSA and treated with ampicillin, ceftazidime, or tetracycline showed enhanced bacterial pathogenicity. The release of induced virulence factors in vivo was confirmed in a histological examination. Subinhibitory concentrations of antibiotics belonging to β-lactam and tetracycline aggravated infection by inducing staphylococcal virulence in vivo. Thus, when antibiotics are required, it is preferable to employ combination therapy and to initiate the appropriate treatment plan, following diagnosis. Our findings emphasize the risks associated with antibiotic-based therapy and underline the need for alternative therapeutic options. IMPORTANCE Antibiotics are widely applied to treat infectious diseases. Empirically treatment with incorrect antibiotics, or even correct antibiotics always falls into subinhibitory concentrations, due to dosing, distribution, or secretion. In this study, we have systematically evaluated in vitro virulence induction effect of antibiotics and in vivo exacerbated infection. The major highlight of this work is to prove the β-lactam and tetracyclines antibiotics exacerbated disease is due to their induction effect on staphylococcal virulence. This phenomenon is common and suggests that if β-lactam antibiotics remain the first line of defense during empirical therapy, we either need to increase patient reliability or the treatment approach may improve in the future when paired with anti-virulence drugs.

Low Environmental Temperature Exacerbates Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Golden Syrian Hamsters

BACKGROUND

The effect of low environmental temperature on viral shedding and disease severity of Coronavirus Disease 2019 (COVID-19) is uncertain.

METHODS

We investigated the virological, clinical, pathological, and immunological changes in hamsters housed at room (21°C), low (12-15°C), and high (30-33°C) temperature after challenge by 105 plaque-forming units of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

RESULTS

The nasal turbinate, trachea, and lung viral load and live virus titer were significantly higher (~0.5-log10 gene copies/β-actin, P < .05) in the low-temperature group at 7 days postinfection (dpi). The low-temperature group also demonstrated significantly higher level of tumor necrosis factor-α, interferon-γ (IFN-γ), interleukin-1β, and C-C motif chemokine ligand 3, and lower level of the antiviral IFN-α in lung tissues at 4 dpi than the other 2 groups. Their lungs were grossly and diffusely hemorrhagic, with more severe and diffuse alveolar and peribronchiolar inflammatory infiltration, bronchial epithelial cell death, and significantly higher mean total lung histology scores. By 7 dpi, the low-temperature group still showed persistent and severe alveolar inflammation and hemorrhage, and little alveolar cell proliferative changes of recovery. The viral loads in the oral swabs of the low-temperature group were significantly higher than those of the other two groups from 10 to 17 dpi by about 0.5-1.0 log10 gene copies/β-actin. The mean neutralizing antibody titer of the low-temperature group was significantly (P < .05) lower than that of the room temperature group at 7 dpi and 30 dpi.

CONCLUSIONS

This study provided in vivo evidence that low environmental temperature exacerbated the degree of virus shedding, disease severity, and tissue proinflammatory cytokines/chemokines expression, and suppressed the neutralizing antibody response of SARS-CoV-2-infected hamsters. Keeping warm in winter may reduce the severity of COVID-19.

Early Treatment of High-Risk Hospitalized Coronavirus Disease 2019 (COVID-19) Patients With a Combination of Interferon Beta-1b and Remdesivir: A Phase 2 Open-label Randomized Controlled Trial

BACKGROUND

Early antiviral therapy was effective in the treatment of coronavirus disease 2019 (COVID-19). We assessed the efficacy and safety of combined interferon beta-1b and remdesivir treatment in hospitalized COVID-19 patients.

METHODS

We conducted a multicentre, prospective open-label, randomized-controlled trial involving high-risk adults hospitalized for COVID-19. Patients were randomly assigned to a 5-day interferon beta-1b 16 million units daily and remdesivir 200 mg loading on day 1 followed by 100 mg daily on day 2 to 5 (combination group), or to remdesivir only of similar regimen (control group) (1:1). The primary endpoint was the time to complete alleviation of symptoms (NEWS2 = 0).

RESULTS

Two-hundred and twelve patients were enrolled. The median days of starting treatment from symptom onset was 3 days. The median age was 65 years, and 159 patients (75%) had chronic disease. The baseline demographics were similar. There was no mortality. For the primary endpoint, the combination group was significantly quicker to NEWS2 = 0 (4 vs 6.5 days; hazard ratio [HR], 6.59; 95% confidence interval [CI], 6.1-7.09; P < .0001) when compared to the control group. For the secondary endpoints, the combination group was quicker to negative nasopharyngeal swab (NPS) viral load (VL) (6 vs 8 days; HR, 8.16; 95% CI, 7.79-8.52; P < .0001) and to develop seropositive immunoglobulin G (IgG) (8 vs 10 days; HR, 10.78; 95% CI, 9.98-11.58; P < .0001). All adverse events resolved upon follow-up. Combination group (HR, 4.1 95% CI, 1.9-8.6, P < .0001) was the most significant independent factor associated with NEWS2 = 0 on day 4.

CONCLUSIONS

Early treatment with interferon beta-1b and remdesivir was safe and better than remdesivir only in alleviating symptoms, and in shortening viral shedding and hospitalization with earlier seropositivity in high-risk COVID-19 patients.

CLINICAL TRIALS REGISTRATION

NCT04647695.

A bipotential organoid model of respiratory epithelium recapitulates high infectivity of SARS-CoV-2 Omicron variant

The airways and alveoli of the human respiratory tract are lined by two distinct types of epithelium, which are the primary targets of respiratory viruses. We previously established long-term expanding human lung epithelial organoids from lung tissues and developed a ‘proximal’ differentiation protocol to generate mucociliary airway organoids. However, a respiratory organoid system with bipotential of the airway and alveolar differentiation remains elusive. Here we defined a ‘distal’ differentiation approach to generate alveolar organoids from the same source for the derivation of airway organoids. The alveolar organoids consisting of type I and type II alveolar epithelial cells (AT1 and AT2, respectively) functionally simulate the alveolar epithelium. AT2 cells maintained in lung organoids serve as progenitor cells from which alveolar organoids derive. Moreover, alveolar organoids sustain a productive SARS-CoV-2 infection, albeit a lower replicative fitness was observed compared to that in airway organoids. We further optimized 2-dimensional (2D) airway organoids. Upon differentiation under a slightly acidic pH, the 2D airway organoids exhibit enhanced viral replication, representing an optimal in vitro correlate of respiratory epithelium for modeling the high infectivity of SARS-CoV-2. Notably, the higher infectivity and replicative fitness of the Omicron variant than an ancestral strain were accurately recapitulated in these optimized airway organoids. In conclusion, we have established a bipotential organoid culture system able to reproducibly expand the entire human respiratory epithelium in vitro for modeling respiratory diseases, including COVID-19.

Computation of Antigenicity Predicts SARS-CoV-2 Vaccine Breakthrough Variants

It has been reported that multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) including Alpha, Beta, Gamma, and Delta can reduce neutralization by antibodies, resulting in vaccine breakthrough infections. Virus–antiserum neutralization assays are typically performed to monitor potential vaccine breakthrough strains. However, experiment-based methods took several weeks whether newly emerging variants can break through current vaccines or therapeutic antibodies. To address this, we sought to establish a computational model to predict the antigenicity of SARS-CoV-2 variants by sequence alone. In this study, we firstly identified the relationship between the antigenic difference transformed from the amino acid sequence and the antigenic distance from the neutralization titers. Based on this correlation, we obtained a computational model for the receptor-binding domain (RBD) of the spike protein to predict the fold decrease in virus–antiserum neutralization titers with high accuracy (~0.79). Our predicted results were comparable to experimental neutralization titers of variants, including Alpha, Beta, Delta, Gamma, Epsilon, Iota, Kappa, and Lambda, as well as SARS-CoV. Here, we predicted the fold of decrease of Omicron as 17.4-fold less susceptible to neutralization. We visualized all 1,521 SARS-CoV-2 lineages to indicate variants including Mu, B.1.630, B.1.633, B.1.649, and C.1.2, which can induce vaccine breakthrough infections in addition to reported VOCs Beta, Gamma, Delta, and Omicron. Our study offers a quick approach to predict the antigenicity of SARS-CoV-2 variants as soon as they emerge. Furthermore, this approach can facilitate future vaccine updates to cover all major variants. An online version can be accessed at http://jdlab.online.

SPINK6 inhibits human airway serine proteases and restricts influenza virus activation

SPINK6 was identified in human skin as a cellular inhibitor of serine proteases of the KLK family. Airway serine proteases are required to cleave hemagglutinin (HA) of influenza A viruses (IAVs) to initiate an infection in the human airway. We hypothesized that SPINK6 may inhibit common airway serine proteases and restrict IAV activation. We demonstrate that SPINK6 specifically suppresses the proteolytic activity of HAT and KLK5, HAT- and KLK5-mediated HA cleavage, and restricts virus maturation and replication. SPINK6 constrains the activation of progeny virions and impairs viral growth; and vice versa, blocking endogenous SPINK6 enhances HA cleavage and viral growth in physiological-relevant human airway organoids where SPINK6 is intrinsically expressed. In IAV-infected mice, SPINK6 significantly suppresses viral growth and improves mouse survival. Notably, individuals carrying the higher SPINK6 expression allele were protected from human H7N9 infection. Collectively, SPINK6 is a novel host inhibitor of serine proteases in the human airway and restricts IAV activation.

Successful treatment of a chronic oroantral fistula infected with extensively drug resistant bacteria using long-term oesophageal tube feeding and several non-conventional treatments in a horse

BACKGROUND

Chronic oroantral fistulae (OAF) with secondary sinusitis can occur following repulsion of cheek teeth in horses.

CASE REPORT

An 8-year-old Andalusian cross gelding presented with an iatrogenic clinical crown fracture of tooth 209, which underwent repulsion of its apical portion (day 0). The horse was treated with intramuscular penicillin and intravenous gentamicin (5 days), followed by oral trimethoprim-sulphonamide (10 days) and then oral doxycycline (14 days). The acute iatrogenic OAF created during the initial repulsion persisted; a chronic OAF was identified on day 24. On day 48, septic sinusitis with multidrug-resistant (MDR) Escherichia coli was confirmed. Although susceptible to enrofloxacin in vitro, 30 days of therapy was unsuccessful. Subsequent serial cultures grew multiple MDR and extensively drug-resistant (XDR) gram-negative microorganisms. Whole-genome sequencing (WGS) revealed multiple sequence types of E. coli, with a range of resistance and virulence genes. The orientation of the OAF, regional osteomyelitis and septic sinusitis were confirmed with computed tomography on day 70. On day 74, enteral nutrition was provided through a cervical oesophagostomy tube for 3 months for prevention of oral feed contamination. The OAF was treated with various alternative therapeutics, including apple cider vinegar, propolis and amikacin impregnated products, until resolution on day 116.

CONCLUSION

These non-conventional therapeutics, antimicrobials and long-term oesophagostomy contributed to the successful treatment of a complicated OAF. In the future, WGS may be useful to inform antimicrobial selection when MDR or XDR organisms are identified.

Epidemiology of Acute Myocarditis/Pericarditis in Hong Kong Adolescents Following Comirnaty Vaccination

BACKGROUND

Age-specific incidence of acute myocarditis/pericarditis in adolescents following Comirnaty vaccination in Asia is lacking. This study aimed to study the clinical characteristics and incidence of acute myocarditis/pericarditis among Hong Kong adolescents following Comirnaty vaccination.

METHODS

This is a population cohort study in Hong Kong that monitored adverse events following immunization through a pharmacovigilance system for COVID-19 vaccines. All adolescents aged between 12 and 17 years following Comirnaty vaccination were monitored under the COVID-19 vaccine Adverse Event Response and Evaluation Programme. The clinical characteristics and overall incidence of acute myocarditis/pericarditis in adolescents following Comirnaty vaccination were analysed.

RESULTS

Between 14 June 2021 and 4 September 2021, 33 Chinese adolescents who developed acute myocarditis/pericarditis following Comirnaty vaccination were identified. 29 (87.88%) were males and 4 (12.12%) were females, with a median age of 15.25 years. 27 (81.82%) and 6 (18.18%) cases developed acute myocarditis/pericarditis after receiving the second and first dose, respectively. All cases are mild and required only conservative management.The overall incidence of acute myocarditis/pericarditis was 18.52 (95% Confidence Interval [CI], 11.67-29.01) per 100,000 persons vaccinated. The incidence after the first and second doses were 3.37 (95%CI 1.12-9.51) and 21.22 (95%CI 13.78-32.28 per 100,000 persons vaccinated, respectively. Among male adolescents, the incidence after the first and second doses were 5.57 (95% CI 2.38-12.53) and 37.32 (95% CI 26.98-51.25) per 100,000 persons vaccinated.

CONCLUSIONS

There is a significant increase in the risk of acute myocarditis/pericarditis following Comirnaty vaccination among Chinese male adolescents, especially after the second dose.

Natural Transmission of Bat-like Severe Acute Respiratory Syndrome Coronavirus 2 Without Proline-Arginine-Arginine-Alanine Variants in Coronavirus Disease 2019 Patients

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contains the furin cleavage Proline-Arginine-Arginine-Alanine (PRRA) motif in the S1/S2 region, which enhances viral pathogenicity but is absent in closely related bat and pangolin coronaviruses. Whether bat-like coronaviral variants without PRRA (∆PRRA) can establish natural infections in humans is unknown.

METHODS

Here, we developed a duplex digital polymerase chain reaction assay to examine ∆PRRA variants in Vero-E6-propagated isolates, human organoids, experimentally infected hamsters, and coronavirus disease 2019 (COVID-19) patients.

RESULTS

We found that SARS-CoV-2, as currently transmitting in humans, contained a quasispecies of wild-type, ∆PRRA variants and variants that have mutations upstream of the PRRA motif. Moreover, the ∆PRRA variants were readily detected despite being at a low intra-host frequency in transmitted founder viruses in hamsters and in COVID-19 patients, including in acute cases and a family cluster, with a prevalence rate of 52.9%.

CONCLUSIONS

Our findings demonstrate that bat-like SARS-CoV-2ΔPRRA not only naturally exists but remains transmissible in COVID-19 patients, which has significant implications regarding the zoonotic origin and natural evolution of SARS-CoV-2.

Potent and protective IGHV3-53/3-66 public antibodies and their shared escape mutant on the spike of SARS-CoV-2

Neutralizing antibodies (nAbs) to SARS-CoV-2 hold powerful potentials for clinical interventions against COVID-19 disease. However, their common genetic and biologic features remain elusive. Here we interrogate a total of 165 antibodies from eight COVID-19 patients, and find that potent nAbs from different patients have disproportionally high representation of IGHV3-53/3-66 usage, and therefore termed as public antibodies. Crystal structural comparison of these antibodies reveals they share similar angle of approach to RBD, overlap in buried surface and binding residues on RBD, and have substantial spatial clash with receptor angiotensin-converting enzyme-2 (ACE2) in binding to RBD. Site-directed mutagenesis confirms these common binding features although some minor differences are found. One representative antibody, P5A-3C8, demonstrates extraordinarily protective efficacy in a golden Syrian hamster model against SARS-CoV-2 infection. However, virus escape analysis identifies a single natural mutation in RBD, namely K417N found in B.1.351 variant from South Africa, abolished the neutralizing activity of these public antibodies. The discovery of public antibodies and shared escape mutation highlight the intricate relationship between antibody response and SARS-CoV-2, and provide critical reference for the development of antibody and vaccine strategies to overcome the antigenic variation of SARS-CoV-2.

A novel linker-immunodominant site (LIS) vaccine targeting the SARS-CoV-2 spike protein protects against severe COVID-19 in Syrian hamsters

The Coronavirus Disease 2019 (COVID-19) pandemic is unlikely to abate until sufficient herd immunity is built up by either natural infection or vaccination. We previously identified ten linear immunodominant sites on the SARS-CoV-2 spike protein of which four are located within the RBD. Therefore, we designed two linkerimmunodominant site (LIS) vaccine candidates which are composed of four immunodominant sites within the RBD (RBD-ID) or all the 10 immunodominant sites within the whole spike (S-ID). They were administered by subcutaneous injection and were tested for immunogenicity and in vivo protective efficacy in a hamster model for COVID-19. We showed that the S-ID vaccine induced significantly better neutralizing antibody response than RBD-ID and alum control. As expected, hamsters vaccinated by S-ID had significantly less body weight loss, lung viral load, and histopathological changes of pneumonia. The S-ID has the potential to be an effective vaccine for protection against COVID-19.

Clinical Characteristics and Transmission of COVID-19 in Children and Youths During 3 Waves of Outbreaks in Hong Kong

IMPORTANCE

Schools were closed intermittently across Hong Kong to control the COVID-19 outbreak, which led to significant physical and psychosocial problems among children and youths.

OBJECTIVE

To compare the clinical characteristics and sources of infection among children and youths with COVID-19 during the 3 waves of outbreaks in Hong Kong in 2020.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study involved children and youths aged 18 years or younger with COVID-19 in the 3 waves of outbreaks from January 23 through December 2, 2020. Data were analyzed from December 2020 through January 2021.

MAIN OUTCOMES AND MEASURES

Demographic characteristics, travel and contact histories, lengths of hospital stay, and symptoms were captured through the central electronic database. Individuals who were infected without recent international travel were defined as having domestic infections.

RESULTS

Among 397 children and youths confirmed with COVID-19 infections, the mean (SD) age was 9.95 (5.34) years, 220 individuals (55.4%) were male, and 154 individuals (38.8%) were asymptomatic. There were significantly more individuals who were infected without symptoms in the second wave (59 of 118 individuals [50.0%]) and third wave (94 of 265 individuals [35.5%]) than in the first wave (1 of 14 individuals [7.1%]) (P = .001). Significantly fewer individuals who were infected in the second and third waves, compared with the first wave, had fever (first wave: 10 individuals [71.4%]; second wave: 22 individuals [18.5%]; third wave: 98 individuals [37.0%]; P < .001) or cough (first wave: 6 individuals [42.9%]; second wave: 15 individuals [12.7%]; third wave: 52 individuals [19.6%]; P = .02). Among all individuals, 394 individuals (99.2%) had mild illness. One patient developed chilblains (ie, COVID toes), 1 patient developed multisystem inflammatory syndrome in children, and 1 patient developed post-COVID-19 autoimmune hemolytic anemia. In all 3 waves, 204 patients with COVID-19 (51.4%) had domestic infections. Among these individuals, 186 (91.2%) reported having a contact history with another individual with COVID-19, of which most (183 individuals [90.0%]) were family members. In the third wave, 18 individuals with domestic infections had unknown contact histories. Three schoolmates were confirmed with COVID-19 on the same day and were reported to be close contacts.

CONCLUSIONS AND RELEVANCE

This cross-sectional study found that nearly all children and youths with COVID-19 in Hong Kong had mild illness. These findings suggest that household transmission was the main source of infection for children and youths with domestic infections and that the risk of being infected at school was small.

Human Intestinal Organoids Recapitulate Enteric Infections of Enterovirus and Coronavirus

Enteroviruses, such as EV-A71 and CVA16, mainly infect the human gastrointestinal tract. Human coronaviruses, including SARS-CoV and SARS-CoV-2, have been variably associated with gastrointestinal symptoms. We aimed to optimize the human intestinal organoids and hypothesize that these optimized intestinal organoids can recapitulate enteric infections of enterovirus and coronavirus. We demonstrate that the optimized human intestinal organoids enable better simulation of the native human intestinal epithelium, and that they are significantly more susceptible to EV-A71 than CVA16. Higher replication of EV-A71 than CVA16 in the intestinal organoids triggers a more vigorous cellular response. However, SARS-CoV and SARS-CoV-2 exhibit distinct dynamics of virus-host interaction; more robust propagation of SARS-CoV triggers minimal cellular response, whereas, SARS-CoV-2 exhibits lower replication capacity but elicits a moderate cellular response. Taken together, the disparate profile of the virus-host interaction of enteroviruses and coronaviruses in human intestinal organoids may unravel the cellular basis of the distinct pathogenicity of these viral pathogens.

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An optimized differentiation protocol improves maturation of intestinal organoids

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SARS-CoV-2 and SARS-CoV infection triggers less robust response than enteroviruses

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Coronaviruses show lower sensitivity to type III IFNs than enteroviruses

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Intestinal organoids recapitulate disparate pathogenicity of CoVs and enteroviruses

Human coronavirus dependency on host heat shock protein 90 reveals an antiviral target

Rapid accumulation of viral proteins in host cells render viruses highly dependent on cellular chaperones including heat shock protein 90 (Hsp90). Three highly pathogenic human coronaviruses, including MERS-CoV, SARS-CoV and SARS-CoV-2, have emerged in the past 2 decades. However, there is no approved antiviral agent against these coronaviruses. We inspected the role of Hsp90 for coronavirus propagation. First, an Hsp90 inhibitor, 17-AAG, significantly suppressed MERS-CoV propagation in cell lines and physiological-relevant human intestinal organoids. Second, siRNA depletion of Hsp90β, but not Hsp90α, significantly restricted MERS-CoV replication and abolished virus spread. Third, Hsp90β interaction with MERS-CoV nucleoprotein (NP) was revealed in a co-immunoprecipitation assay. Hsp90β is required to maintain NP stability. Fourth, 17-AAG substantially inhibited the propagation of SARS-CoV and SARS-CoV-2. Collectively, Hsp90 is a host dependency factor for human coronavirus MERS-CoV, SARS-CoV and SARS-COV-2. Hsp90 inhibitors can be repurposed as a potent and broad-spectrum antiviral against human coronaviruses.

False-positive SARS-CoV-2 serology in 3 children with Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute febrile and eruptive disease with systemic vasculitis predominantly affecting young East Asian children. Recent reports showed that children with KD-like disease from KD low prevalence regions had positive SARS-CoV-2 serology despite a negative SARS-CoV-2 polymerase chain reaction (PCR) in respiratory samples.

OBJECTIVES

To describe 3 pediatric Kawasaki Disease patients with false positive SARS-CoV-2 serology.

STUDY DESIGN

We retrospectively recruited children with KD diagnosed during the COVID-19 outbreak in Hong Kong. Clinical characteristics and laboratory test results including SARS-CoV-2 PCR results were retrieved. We performed a microparticle-based immunoassay for the detection of IgG against nucleoprotein (NP) and spike protein receptor binding domain (RBD), and a microneutralization assay for the detection of neutralizing antibodies.

RESULTS

Three Chinese children with typical KD were identified. They had no epidemiological links with COVID-19 patients and tested negative for SARS-CoV-2 NPA PCR. They were treated with IVIG and aspirin, and were discharged without complications. Subsequently 2 of them were tested positive against anti-RBD and anti-NP antibodies and 1 was tested positive against anti- RBD antibodies. However, microneutralization assay showed that neutralizing antibodies were absent, suggesting a false-positive IgG result.

CONCLUSION

Detection of neutralizing antibodies is recommended to confirm previous SARS-CoV-2 infection in IgG-positive but PCR-negative patients.

IFCC Interim Guidelines on Serological Testing of Antibodies against SARS-CoV-2

Serological testing for the detection of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is emerging as an important component of the clinical management of patients with coronavirus disease 2019 (COVID-19) as well as the epidemiological assessment of SARS-CoV-2 exposure worldwide. In addition to molecular testing for the detection of SARS-CoV-2 infection, clinical laboratories have also needed to increase testing capacity to include serological evaluation of patients with suspected or known COVID-19. While regulatory approved serological immunoassays are now widely available from diagnostic manufacturers globally, there is significant debate regarding the clinical utility of these tests, as well as their clinical and analytical performance requirements prior to application. This document by the International Federation for Clinical Chemistry and Laboratory Medicine (IFCC) Taskforce on COVID-19 provides interim guidance on: (A) clinical indications and target populations, (B) assay selection, (C) assay evaluation, and (D) test interpretation and limitations for serological testing of antibodies against SARS-CoV-2 infection. These evidence-based recommendations will provide practical guidance to clinical laboratories in the selection, verification, and implementation of serological assays and are of the utmost importance as we expand our pandemic response from initial case tracing and containment to mitigation strategies to minimize resurgence and further morbidity and mortality.

Case of "relapsing" COVID-19 in a kidney transplant recipient

Clinical outcomes of COVID‐19 vary considerably between patients. Little was known about the clinical course and optimal management of immunosuppressed patients infected with SARS‐CoV‐2. We report a kidney transplant recipient with COVID‐19 who presented with pneumonitis and acute kidney injury (AKI). She improved after reduction of immunosuppressive treatment and had two consecutive negative reverse transcription polymerase chain reaction (RT‐PCR) tests. Her respiratory tract samples turned positive again afterwards, and she was treated with lopinavir‐ritonavir. She had satisfactory virological and clinical response after a prolonged disease course. This case illustrates the risk of relapse or persisting shedding of SARS‐CoV‐2 in immunosuppressed patients, the important role of viral load monitoring in management, the challenges in balancing the risks of COVID‐19 progression and transplant rejection, and the pharmacokinetic interaction between immunosuppressive and antiviral medications.

Mining of epitopes on spike protein of SARS-CoV-2 from COVID-19 patients

The ongoing coronavirus disease 2019 (COVID-19) pandemic is a serious threat to global public health, and imposes severe burdens on the entire human society. The severe acute respiratory syndrome (SARS) coronavirus-2 (SARS-CoV-2) can cause severe respiratory illness and death. Currently, there are no specific antiviral drugs that can treat COVID-19. Several vaccines against SARS-CoV-2 are being actively developed by research groups around the world. The surface S (spike) protein and the highly expressed internal N (nucleocapsid) protein of SARS-CoV-2 are widely considered as promising candidates for vaccines. In order to guide the design of an effective vaccine, we need experimental data on these potential epitope candidates. In this study, we mapped the immunodominant (ID) sites of S protein using sera samples collected from recently discharged COVID-19 patients. The SARS-CoV-2 S protein-specific antibody levels in the sera of recovered COVID-19 patients were strongly correlated with the neutralising antibody titres. We used epitope mapping to determine the landscape of ID sites of S protein, which identified nine linearized B cell ID sites. Four out of the nine ID sites were found in the receptor-binding domain (RBD). Further analysis showed that these ID sites are potential high-affinity SARS-CoV-2 antibody binding sites. Peptides containing two out of the nine sites were tested as vaccine candidates against SARS-CoV-2 in a mouse model. We detected epitope-specific antibodies and SARS-CoV-2-neutralising activity in the immunised mice. This study for the first time provides human serological data for the design of vaccines against COVID-19.

Polymicrobial Outbreak of Intermittent Peritoneal Dialysis Peritonitis during External Wall Renovation at a Dialysis Center

Objective

To investigate an outbreak of peritonitis in intermittent peritoneal dialysis (IPD) patients.

Design

An outbreak investigation was performed to identify the etiology of the polymicrobial outbreak, and a retrospective case-control study was conducted to assess the risk factors for development of peritonitis.

Setting

Renal dialysis center.

Patients

Ten episodes of peritonitis occurred in 8 of 61 patients over a 6-month period in which 669 IPD procedures were analyzed.

Interventions

Field visit to renal dialysis center to examine the entire IPD procedure, inspect the hospital environment, and perform air bacterial count.

Main Outcome Measures

The environmental factors and risk factors contributing to the polymicrobial peritonitis outbreak in IPD patients. The incidence of IPD peritonitis was determined before and after interventions.

Results

The causative organisms included Acinetobacter baumanii ( 6 ), Stenotrophomonas maltophilia ( 2 ), Pseudomonas aeruginosa ( 1 ), Candida albicans ( 1 ), C. tropicalis ( 1 ), Enterococcus ( 3 ), and Enterobacteriaceae ( 2 ). Four episodes of peritonitis involved infection by more than one organism. Air sampling of the environment detected a median of 110 colony forming units of bacteria per cubic meter of air, 10% of which were found to be Acinetobacter baumanii. The source of this polymicrobial outbreak was attributed to the bamboo scaffolding structure covering the external wall of the hospital during renovation. A retrospective case-control study indicated that the absence of the flush-before-fill step was a risk factor for development of peritonitis.

Conclusion

In addition to invasive aspergillosis in transplant or oncology patients, Acinetobacter peritonitis in dialysis patients should be considered another microbial cause of outbreak associated with hospital renovation.

Identification and characterization of GLDC as host susceptibility gene to severe influenza

Glycine decarboxylase (GLDC) was prioritized as a candidate susceptibility gene to severe influenza in humans. The higher expression of GLDC derived from genetic variations may confer a higher risk to H7N9 and severe H1N1 infection. We sought to characterize GLDC as functional susceptibility gene that GLDC may intrinsically regulate antiviral response, thereby impacting viral replication and disease outcome. We demonstrated that GLDC inhibitor AOAA and siRNA depletion boosted IFNβ‐ and IFN‐stimulated genes (ISGs) in combination with PolyI:C stimulation. GLDC inhibition and depletion significantly amplified antiviral response of type I IFNs and ISGs upon viral infection and suppressed the replication of H1N1 and H7N9 viruses. Consistently, GLDC overexpression significantly promoted viral replication due to the attenuated antiviral responses. Moreover, GLDC inhibition in H1N1‐infected BALB/c mice recapitulated the amplified antiviral response and suppressed viral growth. AOAA provided potent protection to the infected mice from lethal infection, comparable to a standard antiviral against influenza viruses. Collectively, GLDC regulates cellular antiviral response and orchestrates viral growth. GLDC is a functional susceptibility gene to severe influenza in humans.

A Unique Pattern of Staphylococcal Scalded Skin Syndrome-Like Erosions in Patients with Atopic Dermatitis: Dermatitis flammeus

We describe the clinical features of a novel complication in patients with atopic dermatitis (AD). Twenty patients, mean age 23 years, with AD who presented with staphylococcal scalded skin syndrome (SSSS)-like lesions were included between January 2008 and September 2010. Skin lesions followed a triphasic progression pattern from erythema to hyperpigmentation and then erosions. A symmetric and predominant flexural involvement was observed. Pseudomonas aeruginosa (PA) (38.9%) and Staphylococcus epidermidis (38.9%) were the most frequently cultured bacteria from skin swabs. Complete resolution was evident in all cases, and the recurrence rate was 35%. In conclusion, a unique complication characterized by triphasic progression to painful erosions was found in a cluster of AD patients. We propose the new term "dermatitis flammeus" to describe this phenomenon, with PA being one of the etiologies.

Evaluation of the molecular Xpert Xpress Flu/RSV assay vs. Alere i Influenza A & B assay for rapid detection of influenza viruses

A new FDA-approved Xpert Xpress Flu/RSV assay has been released for rapid influenza virus detection. We collected 134 nasopharyngeal specimens to compare the diagnostic performance of the Xpert assay and the Alere i Influenza A & B assay for influenza A and B virus detection. The Xpert assay demonstrated 100% and 96.3% sensitivity to influenza A and influenza B virus respectively. Its specificity was 100% for both viruses. The Alere i assay demonstrated slightly lower sensitivity but similar specificity to the Xpert Xpress assay. Although the Xpert assay (30 min) required longer processing time than the Alere assay (15 min), the handling procedure of the Alere assay was more complicated than the Xpert assay. As the GenXpert system has higher throughput than the Alere system, it is more suitable for hospital clinical laboratories. Overall, the new Xpert Xpress Flu/RSV assay is a reliable and useful tool for rapid influenza detection.

Monitoring the fitness of antiviral-resistant influenza strains during an epidemic: a mathematical modelling study

BACKGROUND

Antivirals (eg, oseltamivir) are important for mitigating influenza epidemics. In 2007, an oseltamivir-resistant influenza seasonal A H1N1 strain emerged and spread to global fixation within 1 year. This event showed that antiviral-resistant (AVR) strains can be intrinsically more transmissible than their contemporaneous antiviral-sensitive (AVS) counterpart. Surveillance of AVR fitness is therefore essential. Our objective was to develop a simple method for estimating AVR fitness from surveillance data.

METHODS

We defined the fitness of AVR strains as their reproductive number relative to their co-circulating AVS counterparts. We developed a simple method for real-time estimation of AVR fitness from surveillance data. This method requires only information on generation time without other specific details regarding transmission dynamics. We first used simulations to validate this method by showing that it yields unbiased and robust fitness estimates in most epidemic scenarios. We then applied this method to two retrospective case studies and one hypothetical case study.

FINDINGS

We estimated that the oseltamivir-resistant A H1N1 strain that emerged in 2007 was 4% (95% credible interval [CrI] 3-5) more transmissible than its oseltamivir-sensitive predecessor and the oseltamivir-resistant pandemic A H1N1 strain that emerged and circulated in Japan during 2013-14 was 24% (95% CrI 17-30) less transmissible than its oseltamivir-sensitive counterpart. We show that in the event of large-scale antiviral interventions during a pandemic with co-circulation of AVS and AVR strains, our method can be used to inform optimal use of antivirals by monitoring intrinsic AVR fitness and drug pressure on the AVS strain.

INTERPRETATION

We developed a simple method that can be easily integrated into contemporary influenza surveillance systems to provide reliable estimates of AVR fitness in real time.

FUNDING

Research Fund for the Control of Infectious Disease (09080792) and a commissioned grant from the Health and Medical Research Fund from the Government of the Hong Kong Special Administrative Region, Harvard Center for Communicable Disease Dynamics from the National Institute of General Medical Sciences (grant number U54 GM088558), Area of Excellence Scheme of the Hong Kong University Grants Committee (grant number AoE/M-12/06).

Implementation of directly observed patient hand hygiene for hospitalized patients by hand hygiene ambassadors in Hong Kong

BACKGROUND

The importance of compliance with hand hygiene by patients is increasingly recognized to prevent health care-associated infections.

METHODS

This descriptive study observed the effects of an education campaign, targeted to increase patients' self-initiated hand hygiene, and a hand hygiene ambassador-initiated directly observed hand hygiene program on patients' hand hygiene compliance in a university-affiliated hospital.

RESULTS

The overall audited compliance of patients' self-initiated hand hygiene was only 37.5%, with a rate of 26.9% (112/416 episodes) before meals and medications, 27.5% (19/69 episodes) after using a urinal or bedpan, and 89.7% (87/97 episodes) after attending toilet facilities. Patients referred from a residential care home for older adults had significantly lower hand hygiene compliance (P = .007). Comparatively, the overall audited compliance of ambassador-initiated directly observed hand hygiene was 97.3% (428/440 episodes), which was significantly higher than patients' self-initiated hand hygiene via a patient education program (37.5%, 218/582 episodes, P < .001).

CONCLUSIONS

Directly observed hand hygiene can play an important role in improving compliance with hand hygiene by hospitalized patients.

Use of fluoroquinolones is the single most important risk factor for the high bacterial load in patients with nasal and gastrointestinal colonization by multidrug-resistant Acinetobacter baumannii

Gastrointestinal colonization by carbapenem-resistant Acinetobacter baumannii (CRAB) and multidrug-resistant Acinetobacter baumannii (MRAB) provides an important reservoir for clinical infections and hospital outbreaks. We conducted a 7-month study in a 3200-bed healthcare network to investigate the prevalence of gastrointestinal colonization of CRAB and MRAB in Hong Kong. Between 1 June and 31 December 2014, a total of 17,760 fecal specimens from 9469 patients were screened. Testing showed that 340 (1.9%) specimens from 224 (2.6%) patients were CRAB-positive, which included 70 (0.39%) MRAB-positive specimens from 54 (0.57%) patients. The presence of wound or ulcer, use of broad-spectrum antibiotics in the preceding 6 months, and residence in elderly homes are independent risk factors for gastrointestinal colonization of CRAB. Quantitative bacterial counts in various body sites (rectal, nasal, axilla, wound, catheterized urine, if available) were performed in 33 (61.1%) of 54 MRAB patients. Ten (30.3%) and 8 (24.2%) patients had high bacterial load (defined as over 3 log10) in rectal and nasal swabs, with a median of 5.04 log10 cfu/ml of rectal swab and 4.89 log10 cfu/ml of nasal swab in saline diluent, respectively. Nine (81.8%) of 11 patients with wounds had high bacterial load in wound swabs, with a median of 5.62 log10 cfu/ml. Use of fluoroquinolones 6 months before admission was the only significant factor associated with high bacterial load in nasal and rectal swabs. With the implementation of directly observed hand hygiene before meals and medications to all conscious hospitalized patients, no hospital outbreaks were observed during our study period.

Hand-touch contact assessment of high-touch and mutual-touch surfaces among healthcare workers, patients, and visitors

BACKGROUND

Unlike direct contact with patients' body, hand hygiene practice is often neglected by healthcare workers (HCWs) and visitors after contact with patients' environment. Contact with hospital environmental items may increase risk of pathogen transmission.

AIM

To enumerate the number of hand-touch contacts by patients, HCWs and visitors with any hospital environmental items.

METHODS

All contact-episodes between person and item were recorded by direct observation in a six-bed cubicle of acute wards for 33 working days. High-touch and mutual-touch items with high contact frequencies by HCWs, patients, and visitors were analysed.

FINDINGS

In total, 1107 person-episodes with 6144 contact-episodes were observed in 66 observation hours (average: 16.8 person-episodes and 93.1 contact-episodes per hour). Eight of the top 10 high-touch items, including bedside rails, bedside tables, patients' bodies, patients' files, linen, bed curtains, bed frames, and lockers were mutually touched by HCWs, patients, and visitors. Bedside rails topped the list with 13.6 contact-episodes per hour (mean), followed by bedside tables (12.3 contact-episodes per hour). Using patients' body contacts as a reference, it was found that medical staff and nursing staff contacted bedside tables [rate ratio (RR): 1.741, 1.427, respectively] and patients' files (RR: 1.358, 1.324, respectively) more than patients' bodies, and nursing staff also contacted bedside rails (RR: 1.490) more than patients' bodies.

CONCLUSION

Patients' surroundings may be links in the transmission of nosocomial infections because many are frequently touched and mutually contacted by HCWs, patients, and visitors. Therefore, the focus of hand hygiene education, environmental disinfection, and other system changes should be enhanced with respect to high-touch and mutual-touch items.

A nurse-delivered brief health education intervention to improve pneumococcal vaccination rate among older patients with chronic diseases: a cluster randomized controlled trial

Background

The 23-valent pneumococcal polysaccharide vaccine is recommended for elders, especially those with chronic conditions.

Objective

The aim of this study was to determine if an additional multi-component health education intervention increases the uptake rate of the pneumococcal vaccination among older patients with chronic diseases.

Methods

A cluster randomized controlled trial was conducted from 3 December 2007 to 7 March 2008. The clusters were the individual weeks within five Hong Kong outpatient clinics over a 10-week period. A sample of 2517 patients aged 65 or above with chronic diseases was recruited. Intervention group received a 3-min brief telephone education intervention before and a 3-min face-to-face intervention during scheduled medical appointments at the respective clinics. All subjects received standard care including health education leaflets and/or a video show at the clinics. Pneumococcal vaccination rate and awareness of the vaccination at 3-month follow up were measured.

Results

The vaccination rate was higher in the intervention group compared to the control group (57% vs 48%; relative risk = 1.20, 95% CI = 1.06–1.37), but the two groups did not differ significantly in their awareness of the vaccination at 3-month follow up (65% vs 59%, relative risk = 0.86, 95% CI = 0.69–1.07).

Discussion

A nurse-delivered brief health education intervention was effective in increasing uptake of pneumococcal vaccination among older patients with chronic diseases.

Use of the human colorectal adenocarcinoma (Caco-2) cell line for isolating respiratory viruses from nasopharyngeal aspirates

The human colorectal adenocarcinoma‐derived Caco‐2 cell line was evaluated as a means isolating common respiratory viruses from nasopharyngeal aspirates for the diagnosis of respiratory diseases. One hundred eighty‐nine direct immunofluorescence positive nasopharyngeal aspirates obtained from patients with various viral respiratory diseases were cultured in the presence of Caco‐2 cells or the following conventional cell lines: LLC‐MK2, MDCK, HEp‐2, and A549. Caco‐2 cell cultures effectively propagated the majority (84%) of the viruses present in nasopharyngeal aspirate samples compared with any positive cultures obtained using the panel cells (78%) or individual cell line MDCK (38%), HEp‐2 (21%), LLC‐MK2 (27%), or A549 (37%) cell lines. The differences against individual cell line were statistically significant (P = < 0.000001). Culture in Caco‐2 cells resulted in the isolation of 85% (36/42) of viruses which were not cultivated in conventional cell lines. By contrast, 80% (24/30) of viruses not cultivated in Caco‐2 cells were isolated using the conventional panel. The findings indicated that Caco‐2 cells were sensitive to a wide range of viruses and can be used to culture a broad range of respiratory viruses. J. Med. Virol. 85:874–879, 2013. © 2013 Wiley Periodicals, Inc.

Development of anti-influenza A compounds: a pilot study

1. There is no effective anti-H5N1 avian influenza agent. 2. A chemical compound— BFDBSC—can inhibit H5N1 virus infection in cell cultures, and such inhibition might be attributable to its halogenated benzoyl residues. 3. This pilot study assessed anti- H5N1 activity and toxicity of four chemical compounds with halogenated benzoyl residues in cell culture system. 4. Two compounds—FPBFDBSC and BFB-gallate— showed higher antiviral effectsthan BFDBSC, whearas the other two—BFB-borneol and BFB-menthol—showed lower antiviral effects. These compounds did not show toxicity. 5. The halogenated benzoyl residues may play a key role in anti-H5N1 effects. However, all these compounds showed poor solubility, which may limit their utility