Evaluation of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Molecular Typing of Acinetobacter baumannii in Comparison with Orthogonal Methods.

Colonization and subsequent health care-associated infection (HCAI) with Acinetobacter baumannii are a concern for vulnerable patient groups within the hospital setting. Outbreaks involving multidrug-resistant strains are associated with increased patient morbidity and mortality and poorer overall outcomes. Reliable molecular typing methods can help to trace transmission routes and manage outbreaks. In addition to methods deployed by reference laboratories, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) may assist by making initial in-house judgments on strain relatedness. However, limited studies on method reproducibility exist for this application. We applied MALDI-TOF MS typing to A. baumannii isolates associated with a nosocomial outbreak and evaluated different methods for data analysis. In addition, we compared MALDI-TOF MS with whole-genome sequencing (WGS) and Fourier transform infrared spectroscopy (FTIR) as orthogonal methods to further explore their resolution for bacterial strain typing. A related subgroup of isolates consistently clustered separately from the main outbreak group by all investigated methods. This finding, combined with epidemiological data from the outbreak, indicates that these methods identified a separate transmission event unrelated to the main outbreak. However, the MALDI-TOF MS upstream approach introduced measurement variability impacting method reproducibility and limiting its reliability as a standalone typing method. Availability of in-house typing methods with well-characterized sources of measurement uncertainty could assist with rapid and dependable confirmation (or denial) of suspected transmission events. This work highlights some of the steps to be improved before such tools can be fully integrated into routine diagnostic service workflows for strain typing. IMPORTANCE Managing the transmission of antimicrobial resistance necessitates reliable methods for tracking outbreaks. We compared the performance of MALDI-TOF MS with orthogonal approaches for strain typing, including WGS and FTIR, for Acinetobacter baumannii isolates correlated with a health care-associated infection (HCAI) event. Combined with epidemiological data, all methods investigated identified a group of isolates that were temporally and spatially linked to the outbreak, yet potentially attributed to a separate transmission event. This may have implications for guiding infection control strategies during an outbreak. However, the technical reproducibility of MALDI-TOF MS needs to be improved for it to be employed as a standalone typing method, as different stages of the experimental workflow introduced bias influencing interpretation of biomarker peak data. Availability of in-house methods for strain typing of bacteria could improve infection control practices following increased reports of outbreaks of antimicrobial-resistant organisms during the COVID-19 pandemic, related to sessional usage of personal protective equipment (PPE).

Clinical Case of Rhino-Orbital Mucormycosis in a Convalescent Covid-19 Patient: Diagnostic and Treatment Tactics

According to current data, SARS-CoV-2 virus has the ability to cause multi-organ pathology, leading to acute damage of various organs and systems and long-term consequences characterized by polymorphic symptoms. Recently, a high incidence of invasive mycoses, particularly mucormycosis - COVID-M, has been noted among the COVID-19 complications. The predisposing factor for the development of this pathology is diabetes mellitus, immunodeficiency states, and prolonged use of high doses of glucocorticosteroids. Mucormycosis is characterized by severe clinical manifestations and high lethality, and timely diagnostics of this pathology often represents a difficult problem. The aim of this study was to analyze a clinical case of rhino-orbital mucormycosis in convalescent COVID-19 patient. In the study, there was used mucopurulent nasal discharge from the patient previously hospitalized with a severe novel coronavirus infection. Here, we describe the methodology allowing to isolate and identify a pure mold fungus culture from the biomaterial using methods of routine bacteriology and MALDI-ToF mass spectrometry. Direct microscopy examination of nasal cavity discharge revealed branched non-septic hyphae with a characteristic branching angle, allowing to preliminarily diagnose invasive mucormycosis. Growth of mycelial fungus colony was observed by using Sabouraud's medium with potassium tellurite. Microscopy of the pure culture revealed branching mycelium without septa, broad, with irregular thickness, unsegregated hyphae, and sporangia with a typical column specific to mucormycetes. Analysis of the obtained mass spectra allowed to establish the microbial species identity as Lichtheimia corymbifera. The latter along with other members of the order Mucorales, are known to cause mucormycosis. As a result of antifungal treatment (Amphotericin B) and timely surgical intervention, the patient was discharged from the hospital with prominent clinical improvement and no complaints during further outpatient follow-up period. The analysis of this clinical case showed the lack of alertness in some clinical diagnostic laboratories to detect pathogens of invasive mycoses. To avoid errors, while making a diagnosis, attention should be paid not only to detection of fungal spores in clinical material, but also take into account the structure of mycelium underlying major difference between yeast-like fungi, higher and lower molds. The isolation and identification of a pure pathogen culture allows to confidently verify the diagnosis, timely correct the treatment tactics and monitor circulation of mycotic agents to prevent occurrence of mycoses in most vulnerable patients cohorts.

Validation of a MALDI-TOF MS Method for SARS-CoV-2 Detection on the Bruker Biotyper and Nasopharyngeal Swabs: A Brazil-UK Collaborative Study.

We developed a MALDI-TOF mass spectrometry method for the detection of the SARS-CoV-2 virus in saliva-gargle samples using Shimadzu MALDI-TOF mass spectrometers in the UK. This was validated in the USA to CLIA-LDT standards for asymptomatic infection detection remotely via sharing protocols, shipping key reagents, video conferencing, and data exchange. In Brazil, more so than in the UK and USA, there is a need to develop non-PCR-dependent, rapid, and affordable SARS-CoV-2 infection screening tests that also identify variant SARS-CoV-2 and other virus infections. In addition, travel restrictions necessitated remote collaboration with validation on the available clinical MALDI-TOF-the Bruker Biotyper (microflex® LT/SH)-and on nasopharyngeal swab samples, as salivary gargle samples were not available. The Bruker Biotyper was shown to be almost log103 more sensitive at the detection of high molecular weight spike proteins. A protocol for saline swab soaks out was developed, and duplicate swab samples collected in Brazil were analyzed by MALDI-TOF MS. The swab collected sample spectra that varied from that of saliva-gargle in three additional mass peaks in the mass region expected for IgG heavy chains and human serum albumin. A subset of clinical samples with additional high mass, probably spike-related proteins, were also found. Further, spectral data comparisons and analysis, subjected to machine learning algorithms in order to resolve RT-qPCR positive from RT-qPCR negative swab samples, showed 56-62% sensitivity, 87-91% specificity, and a 78% agreement with RT-qPCR scoring for SARS-CoV-2 infection.

A multiplex method for detection of SARS-CoV-2 variants based on MALDI-TOF mass spectrometry.

The recent outbreak of the coronavirus disease 2019 (COVID-19) pandemic and the continuous evolution of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have highlighted the significance of new detection methods for global monitoring and prevention. Although quantitative reverse transcription PCR (RT-qPCR), the current gold standard for diagnosis, performs excellently in genetic testing, its multiplexing capability is limited because of the signal crosstalk of various fluorophores. Herein, we present a highly efficient platform which combines 17-plex assays with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), enabling the targeting of 14 different mutation sites of the spike gene. Diagnosis using a set of 324 nasopharyngeal swabs or sputum clinical samples with SARS-CoV-2 MS method was identical to that with the RT-qPCR. The detection consistency of mutation sites was 97.9% (47/48) compared to Sanger sequencing without cross-reaction with other respiratory-related pathogens. Therefore, the MS method is highly potent to track and assess SARS-CoV-2 changes in a timely manner, thereby aiding the continuous response to viral variation and prevention of further transmission.

Evolución de la microbiota en un aula de farmacia pre y post primera oleada de la pandemia COVID-19

La microbiota varía con el tiempo, por ello durante el curso académico 2019-20, coincidiendo con la pandemia SARS-COV-2, se evaluó la evolución de la misma en un aula de la Facultad de Farmacia de la Universidad de Salamanca con la espectrometría de masas Matrix-assisted laser desorption ionization time-of-flight. Además, se comparó con otros estudios, así como con las directrices de la Comisión de la Comunidad Europea de calidad del aire de interiores. Tras el estudio se concluyó que dicha aula presentaba un grado de contaminación muy bajo, y que la mayoría de la microbiota era saprofítica. Asimismo, de forma general se puede concluir que de forma cuantitativa los hongos y de forma cuali-cuantitativa las bacterias no presentaban un riesgo para la salud. Por otro lado, entre las variables más importantes encontramos la afluencia de personas, la frecuencia de limpieza y la ventilación. Finalmente, este estudio recoge la poca normativa que existe sobre la calidad del aire en interiores no industriales y no hospitalarios.Alternate abstract:Microbiota varies over time, therefore during 2019-20 academic year, coinciding with the SARS-COV-2 pandemic, the evolution of it was evaluated in a classroom of the Faculty of Pharmacy of the University of Salamanca with mass spectrometry Matrix-assisted laser desorption ionization time-of-flight. In addition, this study was compared with others, as well as with guidelines of the European Community Commission on indoor air quality. After the study, it was concluded that said classroom had very low contamination degree and that most of microbiota was saprophytic. Furthermore, it can be concluded that quantitatively fungi and quantitatively and qualitatively the bacteria did not present a health risk. On the other hand, the most important variables that were found were the influx of people, the frequency of cleaning and ventilation. Finally, this study shows off the lack of regulation that exists on air quality in non-industrial and non-hospital interiors.

Changes in the Protein Profile in Staphylococcal Strains from Patients Infected with the SARS-CoV-2 Virus.

Staphylococcus aureus strains are particularly often isolated from patients with SARS-CoV-2 infection. The aim of the current research was to determine whether the SARS-CoV-2 virus infection affects the protein profile of S. aureus. Bacteria were isolated from the forty swabs collected from the patients in the hospitals of the Pomeranian region. MALDI-TOF MS spectra were obtained using a Microflex LT instrument. Twenty-nine peaks were identified. The peak (2,430) is described here for the first time and was unique for the isolates from patients infected with the SARS-CoV-2 virus. These results support the hypothesis of bacterial adaptation to the conditions caused by viral infection.

How to dissect viral infections and their interplay with the host-proteome by immunoaffinity and mass spectrometry: A tutorial

[Display omitted] • Immunohistochemistry with magnetic core nanoparticles to isolate viruses. • The use of MALDI-MS for rapid virus detection is explained in detail. • The use of ESI-MS/MS to pinpoint host-patient crosstalk is explained in detail. • The absolute quantitative MS is explained for large-scale protein quantitation. The capabilities of bioanalytical mass spectrometry to (i) detect and differentiate viruses at the peptide level whilst maintaining high sample throughput and (ii) to provide diagnosis and prognosis for infected patients are presented as a tutorial in this work to aid analytical chemists and physicians to gain insights into the possibilities offered by current high-resolution mass spectrometry technology and bioinformatics. From (i) sampling to sample treatment;(ii) Matrix-Assisted Laser Desorption Ionization- to Electrospray Ionization -based mass spectrometry;and (iii) from clustering to peptide sequencing;a detailed step-by-step guide is provided and exemplified using SARS-CoV-2 Spike Y839 variant and the variant of concern SARS-CoV-2 Alpha (B.1.1.7 lineage), Influenza B, and Influenza A subtypes AH1N1pdm09 and AH3N2. [ FROM AUTHOR]

Discrimination of influenza A virus subtypes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Influenza is a contagious respiratory illness caused by influenza viruses which possess the enormous threat to older people and young children. Rapid and precise discrimination of virus subtypes are quite crucial for the early therapy, prophylaxis and the prevention of epidemic outbreaks. Herein, a universal strategy, with influenza A virus (IAV) as a model, is proposed for the discrimination of virus subtypes based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Reference library based on nine IAVs subtypes (i.e., H1N1, H3N2, H4N8, H5N8, H6N6, H7N7, H9N2, H10N8, and H11N8) was set up for matching various IAVs subtypes. The simulative test spectra from IAVs showed that the corresponding IAVs subtypes could be distinguished in 90 min, accurately. Furthermore, the principal component analysis results also show that nine virus subtypes can be reliably distinguished. More importantly, this strategy provides an alternative method for identifying and distinguishing other viruses with high variability characteristics, such as SARS-CoV-2, which could be helpful for implementing public health strategies to counter pandemics. A MALDI-TOF MS based universal strategy for the discrimination of virus subtypes was developed, which possess the advantages of speed and high-accuracy. [Display omitted] • A home-made identification database of influenza A virus subtypes was set up. • The discrimination of influenza A virus subtypes could be finished within 90 min. • The influenza A virus subtypes could be distinguished with high accuracy. [ FROM AUTHOR]

Structural and Immunoreactivity Properties of the SARS-CoV-2 Spike Protein upon the Development of an Inactivated Vaccine.

Inactivated vaccines are promising tools for tackling the COVID-19 pandemic. We applied several protocols for SARS-CoV-2 inactivation (by ß-propiolactone, formaldehyde, and UV radiation) and examined the morphology of viral spikes, protein composition of the preparations, and their immunoreactivity in ELISA using two panels of sera collected from convalescents and people vaccinated by Sputnik V. Transmission electron microscopy (TEM) allowed us to distinguish wider flail-like spikes (supposedly the S-protein's pre-fusion conformation) from narrower needle-like ones (the post-fusion state). While the flails were present in all preparations studied, the needles were highly abundant in the ß-propiolactone-inactivated samples only. Structural proteins S, N, and M of SARS-CoV-2 were detected via mass spectrometry. Formaldehyde and UV-inactivated samples demonstrated the highest affinity/immunoreactivity against the convalescent sera, while ß-propiolactone (1:2000, 36 h) and UV-inactivated ones were more active against the sera of people vaccinated with Sputnik V. A higher concentration of ß-propiolactone (1:1000, 2 h) led to a loss of antigenic affinity for both serum panels. Thus, although we did not analyze native SARS-CoV-2 for biosafety reasons, our comparative approach helped to exclude some destructive inactivation conditions and select suitable variants for future animal research. We believe that TEM is a valuable tool for inactivated COVID-19 vaccine quality control during the downstream manufacturing process.

An Unusual Case of Severe Pneumonia Caused Due Candida Tropicalis With a Favorable Clinical Response to Antifungals in a Nonimmunocompromised Patient From the Community.

Severe pneumonia due to Candida tropicalis infection mainly occurs in immunosuppressed patients or those currently receiving broad-spectrum antibiotics. Herein, we report a case of severe pneumonia caused due to C tropicalis in an elderly patient. A 72-year-old man with a previous history of hypertension, ischemic stroke, and facial paralysis sequelae treated with the botulinic toxin, was admitted to the hospital for dyspnea. Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) infection was negative. Computed tomography of the chest revealed bilateral consolidation with left predominance. A bronchoalveolar lavage sample was sent to molecular biology, but no microorganisms were detected using a FilmArray respiratory panel. However, mamanocandidas test for candida was 166 pg/mL (positive), and fungal structures were identified by the MALDI-TOF Biotyper mass spectrometry and attributed to C tropicalis. Antifungal therapy was started using caspofungin 75 mg as the initial dose followed by 50 mg daily. After 10 days of treatment, ventilatory weaning was achieved. By day 14, the patient was decannulated from the tracheostomy. Oral antifungal treatment with voriconazole was continued, and he was discharged from intensive care in good clinical condition. Severe pneumonia due to C tropicalis might occur in specific cases, especially in those patients with risk factors, and must thus be considered when approaching such cases.

"How to dissect viral infections and their interplay with the host-proteome by immunoaffinity and mass spectrometry: A tutorial.”

The capabilities of bioanalytical mass spectrometry to (i) detect and differentiate viruses at the peptide level whilst maintaining high sample throughput and (ii) to provide diagnosis and prognosis for infected patients are presented as a tutorial in this work to aid analytical chemists and physicians to gain insights into the possibilities offered by current high-resolution mass spectrometry technology and bioinformatics. From (i) sampling to sample treatment;(ii) Matrix-Assisted Laser Desorption Ionization- to Electrospray Ionization -based mass spectrometry;and (iii) from clustering to peptide sequencing;a detailed step-by-step guide is provided and exemplified using SARS-CoV-2 Spike Y839 variant and the variant of concern SARS-CoV-2 Alpha (B.1.1.7 lineage), Influenza B, and Influenza A subtypes AH1N1pdm09 and AH3N2.

Discrimination of influenza A virus subtypes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Influenza is a contagious respiratory illness caused by influenza viruses which possess the enormous threat to older people and young children. Rapid and precise discrimination of virus subtypes are quite crucial for the early therapy, prophylaxis and the prevention of epidemic outbreaks. Herein, a universal strategy, with influenza A virus (IAV) as a model, is proposed for the discrimination of virus subtypes based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Reference library based on nine IAVs subtypes (i.e., H1N1, H3N2, H4N8, H5N8, H6N6, H7N7, H9N2, H10N8, and H11N8) was set up for matching various IAVs subtypes. The simulative test spectra from IAVs showed that the corresponding IAVs subtypes could be distinguished in 90 min, accurately. Furthermore, the principal component analysis results also show that nine virus subtypes can be reliably distinguished. More importantly, this strategy provides an alternative method for identifying and distinguishing other viruses with high variability characteristics, such as SARS-CoV-2, which could be helpful for implementing public health strategies to counter pandemics.

Direct Detection of Glycated Human Serum Albumin and Hyperglycosylated IgG3 in Serum, by MALDI-ToF Mass Spectrometry, as a Predictor of COVID-19 Severity.

The prefusion spike protein of SARS-CoV-2 binds advanced glycation end product (AGE)-glycated human serum albumin (HSA) and a higher mass (hyperglycosylated/glycated) immunoglobulin (Ig) G3, as determined by matrix assisted laser desorption mass spectrometry (MALDI-ToF). We set out to investigate if the total blood plasma of patients who had recovered from acute respiratory distress syndrome (ARDS) as a result of COVID-19, contained more glycated HSA and higher mass (glycosylated/glycated) IgG3 than those with only clinically mild or asymptomatic infections. A direct serum dilution, and disulphide bond reduction, method was developed and applied to plasma samples from SARS-CoV-2 seronegative (n = 30) and seropositive (n = 31) healthcare workers (HCWs) and 38 convalescent plasma samples from patients who had been admitted with acute respiratory distress (ARDS) associated with COVID-19. Patients recovering from COVID-19 ARDS had significantly higher mass AGE-glycated HSA and higher mass IgG3 levels. This would indicate that increased levels and/or ratios of hyper-glycosylation (probably terminal sialic acid) IgG3 and AGE glycated HSA may be predisposition markers for the development of COVID-19 ARDS as a result of SARS-CoV2 infection. Furthermore, rapid direct analysis of serum/plasma samples by MALDI-ToF for such humoral immune correlates of COVID-19 presents a feasible screening technology for the most at risk; regardless of age or known health conditions.

CLINICAL CASE OF RHINO-ORBITAL MUCORMYCOSIS IN A CONVALESCENT COVID-19 PATIENT: DIAGNOSTIC AND TREATMENT TACTICS.

According to current data, SARS-CoV-2 virus has the ability to cause multi-organ pathology, leading to acute damage of various organs and systems and long-term consequences characterized by polymorphic symptoms. Recently, a high incidence of invasive mycoses, particularly mucormycosis - COVID-M, has been noted among the COVID-19 complications. The predisposing factor for the development of this pathology is diabetes mellitus, immunodeficiency states, and prolonged use of high doses of glucocorticosteroids. Mucormycosis is characterized by severe clinical manifestations and high lethality, and timely diagnostics of this pathology often represents a difficult problem. The aim of this study was to analyze a clinical case of rhino-orbital mucormycosis in convalescent COVID-19 patient. In the study, there was used mucopurulent nasal discharge from the patient previously hospitalized with a severe novel coronavirus infection. Here, we describe the methodology allowing to isolate and identify a pure mold fungus culture from the biomaterial using methods of routine bacteriology and MALDIToF mass spectrometry. Direct microscopy examination of nasal cavity discharge revealed branched non-septic hyphae with a characteristic branching angle, allowing to preliminarily diagnose invasive mucormycosis. Growth of mycelial fungus colony was observed by using Sabouraud’s medium with potassium tellurite. Microscopy of the pure culture revealed branching mycelium without septa, broad, with irregular thickness, unsegregated hyphae, and sporangia with a typical column specific to mucormycetes. Analysis of the obtained mass spectra allowed to establish the microbial species identity as Lichtheimia corymbifera. The latter along with other members of the order Mucorales, are known to cause mucormycosis. As a result of antifungal treatment (Amphotericin B) and timely surgical intervention, the patient was discharged from the hospital with prominent clinical improvement and no complaints during further outpatient follow-up period. The analysis of this clinical case showed the lack of alertness in some clinical diagnostic laboratories to detect pathogens of invasive mycoses. To avoid errors, while making a diagnosis, attention should be paid not only to detection of fungal spores in clinical material, but also take into account the structure of mycelium underlying major difference between yeast-like fungi, higher and lower molds. The isolation and identification of a pure pathogen culture allows to confidently verify the diagnosis, timely correct the treatment tactics and monitor circulation of mycotic agents to prevent occurrence of mycoses in most vulnerable patients cohorts. (English) [ FROM AUTHOR] Согласно современным данным вирус SARS-CoV-2 обладает способностью вызывать полиорганную патологию, приводя к острым повреждениям различных органов и систем и долгосрочным последствиям, характеризующимся полиморфной симптоматикой. Ð’ последнее время среди осложнений COVID-19 отмечается высокая распространенность инвазивных микозов, в частности мукормикоза — COVID-M. Предрасполагающим фактором развития данной патологии являются сахарный диабет, иммунодефицитные состояния, длительное применение высоких доз глюкокортикостероидов. Мукормикоз отличается тяжестью клинических проявлений и высокой летальностью, своевременная диагностика данной патологии нередко является сложной проблемой. Целью настоящего исследования стал анализ клинического случая риноорбитального мукормикоза у больной, перенесшей COVID-19. Ð’ качестве материала для исследования послужило слизисто-гнойное отделяемое полости носа больной, находившейся ранее на стационарном лечении с диагнозом «Новая коронавирусная инфекция тяжелого течения». Ð’ статье приведена методика, позволяющая выделить и идентифицировать чистую культуру плесневого гриба из биоматериала с использованием методов классической бактериологии и MALDI-ToF массспектрометрии. При исследовании отделяемого носовой полости методом прямой микроскопии были обнаружены разветвленные несептированные гифы с характерным углом ветвления, что позволило поставить предварительный диагноз «Инвазивный мукормикоз». При использовании среды Сабуро с теллуритом калия был отмечен рост колонии мицелиального гриба. При микроскопии чистой культуры были обнаружены типичные для мукормицетов ветвистый мицелий без перегородок, широкие, неравномерные по толщине, несептированные гифы и спорангии с типичной колонкой. Анализ полученных масс-спектров позволил установить видовую принадлежность исследуемого микроорганизма: Lichtheimia corymbifera. Как известно, лихтеймии, наряду с другими представителями порядка Mucorales, являются возбудителями мукормикозов. Врезультате проводимого лечения противогрибковым препаратом (Амфотерицин Ð’) и своевременного оперативного вмешательства больная была выписана из стационара со значительным улучшением, при дальнейшем амбулаторном наблюдении жалоб не Ð¿Ñ€ÐµÐ´Ñ ÑÐ²Ð»ÑÐ»Ð°. Анализ данного клинического случая показал отсутствие ориентированности некоторых клинико-диагностических лабораторий на обнаружение возбудителей инвазивных микозов. Чтобы избежать ошибок при постановке диагноза, необходимо обращать внимание не только на обнаружение спор грибов в клиническом материале, но и принимать во внимание строение мицелия, что является основным различием между дрожжеподобными грибами, высшими и низшими плесенями. Выделение и идентификация чистой культуры возбудителя позволяет уверенно верифицировать диагноз, своевременно корректировать тактику лечения и осуществлять наблюдение за циркуляцией возбудителей мукормикозов для предотвращения возникновения микозов у особо уязвимых контингентов больных. (Russian) [ FROM AUTHOR] Copyright of Russian Journal of Infection & Immunity is the property of National Electronic-Information Consortium and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Serum peptidome profiles immune response of COVID-19 Vaccine administration.

Background: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused significant loss of life and property. In response to the serious pandemic, recently developed vaccines against SARS-CoV-2 have been administrated to the public. Nevertheless, the research on human immunization response against COVID-19 vaccines is insufficient. Although much information associated with vaccine efficacy, safety and immunogenicity has been reported by pharmaceutical companies based on laboratory studies and clinical trials, vaccine evaluation needs to be extended further to better understand the effect of COVID-19 vaccines on human beings. Methods: We performed a comparative peptidome analysis on serum samples from 95 participants collected at four time points before and after receiving CoronaVac. The collected serum samples were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to profile the serum peptides, and also subjected to humoral and cellular immune response analyses to obtain typical immunogenicity information. Results: Significant difference in serum peptidome profiles by MALDI-TOF MS was observed after vaccination. By supervised statistical analysis, a total of 13 serum MALDI-TOF MS feature peaks were obtained on day 28 and day 42 of vaccination. The feature peaks were identified as component C1q receptor, CD59 glycoprotein, mannose-binding protein C, platelet basic protein, CD99 antigen, Leucine-rich alpha-2-glycoprotein, integral membrane protein 2B, platelet factor 4 and hemoglobin subunits. Combining with immunogenicity analysis, the study provided evidence for the humoral and cellular immune responses activated by CoronaVac. Furthermore, we found that it is possible to distinguish neutralizing antibody (NAbs)-positive from NAbs-negative individuals after complete vaccination using the serum peptidome profiles by MALDI-TOF MS together with machine learning methods, including random forest (RF), partial least squares-discriminant analysis (PLS-DA), linear support vector machine (SVM) and logistic regression (LR). Conclusions: The study shows the promise of MALDI-TOF MS-based serum peptidome analysis for the assessment of immune responses activated by COVID-19 vaccination, and discovered a panel of serum peptides biomarkers for COVID-19 vaccination and for NAbs generation. The method developed in this study can help not only in the development of new vaccines, but also in the post-marketing evaluation of developed vaccines.

A Robust, Highly Multiplexed Mass Spectrometry Assay to Identify SARS-CoV-2 Variants.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are characterized by differences in transmissibility and response to therapeutics. Therefore, discriminating among them is vital for surveillance, infection prevention, and patient care. While whole-genome sequencing (WGS) is the "gold standard" for variant identification, molecular variant panels have become increasingly available. Most, however, are based on limited targets and have not undergone comprehensive evaluation. We assessed the diagnostic performance of the highly multiplexed Agena MassARRAY SARS-CoV-2 Variant Panel v3 to identify variants in a diverse set of 391 SARS-CoV-2 clinical RNA specimens collected across our health systems in New York City, USA and Bogotá, Colombia (September 2, 2020 to March 2, 2022). We demonstrated almost perfect levels of interrater agreement between this assay and WGS for 9 of 11 variant calls (κ ≥ 0.856) and 25 of 30 targets (κ ≥ 0.820) tested on the panel. The assay had a high diagnostic sensitivity (≥93.67%) for contemporary variants (e.g., Iota, Alpha, Delta, and Omicron [BA.1 sublineage]) and a high diagnostic specificity for all 11 variants (≥96.15%) and all 30 targets (≥94.34%) tested. Moreover, we highlighted distinct target patterns that could be utilized to identify variants not yet defined on the panel, including the Omicron BA.2 and other sublineages. These findings exemplified the power of highly multiplexed diagnostic panels to accurately call variants and the potential for target result signatures to elucidate new ones. IMPORTANCE The continued circulation of SARS-CoV-2 amid limited surveillance efforts and inconsistent vaccination of populations has resulted in the emergence of variants that uniquely impact public health systems. Thus, in conjunction with functional and clinical studies, continuous detection and identification are quintessential to informing diagnostic and public health measures. Furthermore, until WGS becomes more accessible in the clinical microbiology laboratory, the ideal assay for identifying variants must be robust, provide high resolution, and be adaptable to the evolving nature of viruses like SARS-CoV-2. Here, we highlighted the diagnostic capabilities of a highly multiplexed commercial assay to identify diverse SARS-CoV-2 lineages that circulated from September 2, 2020 to March 2, 2022 among patients seeking care in our health systems. This assay demonstrated variant-specific signatures of nucleotide/amino acid polymorphisms and underscored its utility for the detection of contemporary and emerging SARS-CoV-2 variants of concern.

Machine Learning Approaches to Analyze MALDI-TOF Mass Spectrometry Protein Profiles.

Machine learning is being employed for the development of diagnostic methods for several diseases, but prognostic techniques are still poorly explored. The development of such approaches is essential to assist healthcare workers to ensure the most appropriate treatment for patients. In this chapter, we demonstrate a detailed protocol for the application of machine learning to MALDI-TOF MS spectra of COVID-19-infected plasma samples for risk classification and biomarker identification.

Identification of Circulating Biomarkers of COVID-19 Using MALDI-TOF Mass Spectrometry.

Matrix-assisted laser desorption/ionization source coupled with time-of-flight mass analyzer mass spectrometry (MALDI-TOF MS) is being widely used to obtain proteomic profiles for clinical purposes, as a fast, low-cost, robust, and efficient technique. Here we describe a method for biofluid analysis using MALDI-TOF MS for rapid acquisition of proteomic signatures of COVID-19 infected patients. By using solid-phase extraction, the method allows the analysis of biofluids in less than 15 min.

MALDI-TOF Mass Spectrometric Detection of SARS-CoV-2 Using Cellulose Sulfate Ester Enrichment and Hot Acid Treatment.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the ongoing coronavirus disease 2019 (COVID-19) pandemic. Here we report a novel strategy for the rapid detection of SARS-CoV-2 based on an enrichment approach exploiting the affinity between the virus and cellulose sulfate ester functional groups, hot acid hydrolysis, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Virus samples were enriched using cellulose sulfate ester microcolumns. Virus peptides were prepared using the hot acid aspartate-selective hydrolysis and characterized by MALDI-TOF MS. Collected spectra were processed with a peptide fingerprint algorithm, and searching parameters were optimized for the detection of SARS-CoV-2. These peptides provide high sequence coverage for nucleocapsid (N protein) and allow confident identification of SARS-CoV-2. Peptide markers contributing to the detection were rigorously identified using bottom-up proteomics. The approach demonstrated in this study holds the potential for developing a rapid assay for COVID-19 diagnosis and detecting virus variants from a variety of sources, such as sewage and nasal swabs.

Quarterly report of investigations of suspected exotic diseases: July to September 2021

Exotic pest and disease investigations are managed and reported by the Ministry for Primary Industries' (MPI's) Diagnostic and Surveillance Directorate. This article presents a summary of investigations of suspect exotic and emerging pests and diseases in New Zealand during the period from July to September 2021.