Serological Testing Methods Research Articles

Establishment of two serological methods for detecting IgG and neutralizing antibodies against Crimean-Congo hemorrhagic fever virus glycoprotein.

The Crimean-Congo hemorrhagic fever virus (CCHFV), the most geographically widespread tick-borne virus, is endemic in Africa, Eastern Europe and Asia, with infection resulting in mortality in up to 30% of cases. Currently, there are no approved vaccines or effective therapies available for CCHF. The CCHFV should only be manipulated in the BSL-4 laboratory, which has severely hampered basic seroprevalence studies. In the present study, two antibody detection methods in the forms of an enzyme-linked immunosorbent assay (ELISA) and a surrogate virus neutralization test (sPVNT) were developed using a recombinant glycoprotein (rGP) and a vesicular stomatitis virus (VSV)-based virus bearing the CCHFV recombinant glycoprotein (rVSV/CCHFV) in a biosafety level 2 (BSL-2) laboratory, respectively. The rGP-based ELISA and rVSV/CCHFV-based sVNT were established by using the anti-CCHFV pre-GC mAb 11E7, known as a broadly cross-reactive, potently neutralizing antibody, and their applications as diagnostic antigens were validated for the specific detection of CCHFV IgG and neutralizing antibodies in experimental animals. In two tests, mAb clone 11E7 (diluted at 1:163840 or 512) still displayed positive binding and neutralization, and the presence of antibodies (IgG and neutralizing) against the rGP and rVSV/CCHFV was also determined in the sera from the experimental animals. Both mAb 11E7 and animal sera showed a high reactivity to both antigens, indicating that bacterially expressed rGP and rVSV/CCHFV have good immunoreactivity. Apart from establishing two serological testing methods, their results also demonstrated an imperfect correlation between IgG and neutralizing antibodies. Within this limited number of samples, the rGP and rVSV/CCHFV could be safe and convenient tools with significant potential for research on specific antibodies and serological samples.

Development of a Synthesized Gene Unique to Lumpy Skin Disease Virus and Its Application in Serological Differentiation of Naturally Infected from Vaccinated Cattle with Attenuated Goat Pox Vaccine

Lumpy skin disease (LSD) is an important infectious disease caused by lumpy skin disease virus (LSDV) in bovine. LSDV, sheep pox virus (SPPV), and goat pox virus (GTPV) from the same genus Capripoxvirus (CaPV) of the Poxviridae family exhibit a nucleotide sequence similarity of up to 97%. Therefore, attenuated vaccines of GTPV and SPPV are often used to vaccinate cattle against LSD. However, available serological testing methods cannot accurately differentiate cattle vaccinated with GTPV from those infected with LSDV, posing a significant risk for disease spread. In this study, we developed a synthesized gene unique to LSDV as a differential antigen to detect serum antibodies specific to LSDV and differentiate naturally infected from vaccinated animals (DIVA). We used it for an in‐house indirect enzyme‐linked immunosorbent assay (iELISA), and no cross‐reaction with positive sera for bovine viral diarrhea virus (BVDV), infectious bovine rhinotracheitis virus (IBRV), Mycobacterium bovis (M. Tb), Pasteurella multocida (P. multocida), and Mycoplasma bovis (M. bovis). The cut‐off value (S/P%) was 30% for in‐house iELISA. The corresponding diagnostic specificity was 100% (95% CI: 88.43–100), and the diagnostic sensitivity was 93.3% (95% CI: 77.93–99.18). The intra‐assay coefficient of variation (CV) ranged from 1.08% to 4.11%, and the interassay CV was 0.00%–8.90%. Furthermore, 200 clinical serum samples were examined, in the vaccinated herd, there were no positive samples (0/141) indicating the strong differentiation ability of this method. On the other hand, in the infected herds, the overall positivity was 33.90% (20/59) (95% CI: 22.08–47.39). In summary, a valuable synthesized protein unique to LSDV was developed and showed a promising application in an iELISA with high specificity and sensitivity in differentiating cattle infected with LSDV from those vaccinated with GTPV.

Detection of Mycoplasma gallisepticum, Isolation, and Determination of Tylosin Susceptibility of Isolates from Commercial Chickens.

Mycoplasma gallisepticum (MG) is a contagious avian pathogen that causes financial losses to the poultry industry. Isolation of the pathogen is difficult and time-consuming, and therefore, far from a routine method. Serological testing methods to detect antibodies resistant to MG are widely used in routine diagnosis. Tylosin is a class of macrolide antibiotics tremendously administered in veterinary medicine for the treatment of mycoplasmosis and prophylaxis. This study aimed to detect MG by immunoassay testing, culture, and polymerase chain reaction (PCR) in commercial poultry farms and to investigate the tylosin susceptibility of the isolates. To verify the presence of antibodies resistant to MG, 750 blood samples were randomly collected from 38 broiler farms from 2019 to 2022 in Mazandaran and Golestan provinces, Iran, and rapid slide agglutination (RSA) assay was performed. Positive results were analyzed by the enzyme-linked immunosorbent assay (ELISA) for further investigation. Here, 920 swab samples were collected from 38 non-vaccinated commercial farms for culture, and PCR tests were performed for the isolated strains. The activities of tylosin were tested in vitro against these isolates using the broth microdilution method. The lowest antibiotic concentration that resulted in a color change was considered the minimum inhibitory concentration (MIC) value. Twenty-four (63.1%) farms were positive in the RSA test, and 21 (55.2%) farms were positive in the ELISA test. Nine (23.68%) of the farms grew on culture media, and 8 (21.05%) were detected as Gallisepticum species by PCR. The geometric mean of MIC for tylosin was 5.75 µg/ml, MIC50 was 4 µg/ml, and MIC90 was 8 µg/ml. The results indicated that commercial farms were infected with MG. Considering the ability of MG to spread and the probable use of the RSA test as a rapid and cheap method, it can be argued that ELISA and RSA serological tests can be used to find MG in poultry flocks, and the positive result should be confirmed by standard microbiological tests or PCR. It was also found that the isolated parts of MG changed their sensitivity to tylosin, indicating the need for routine testing to optimize treatment dose and efficiency.

Evaluation of acellular pertussis vaccine: comparisons among different strains of mice

ABSTRACT The current study was designed to comparatively analyse the reactions of different mouse strains in response to acellular pertussis (aP) vaccine, with attempt to further provide a reference for aP vaccine evaluation. NIH mice, ICR mice, and BALB/c mice adopted from different pharmacopoeias and studies were utilized to measure the immune protection and immunogenicity of the same batch of aP vaccine according to the Modified intracerebral challenge assay (MICA) from some Asian pharmacopoeias and the pertussis serological potency test (PTST) method from European Pharmacopoeia. Based on our results, the aP vaccine detected by NIH mice had the best potency. So the NIH mice were more suitable for detecting the immune protection of aP vaccine by the MICA method. Given that the levels of PT-IgG and FHA-IgG antibodies in ICR mice were the highest, and the levels of Th1 and Th2 cells were significantly increased (P < .01), it was more suitable for the detection of immunogenicity of aP vaccine by PSPT method. Spleen lymphocytes were stimulated by PT and FHA. And the levels of IL-4 in ICR mice and NIH mice were significantly increased, so were the levels of IL-17, IL-23, IL-27, and TNF-α in BALB/c mice. NIH mice have stronger adaptive immunity and the weakest inflammatory response, and ICR mice have enhanced adaptive immunity and inflammatory responses, both of which can be thereby used for evaluation by different pharmacopoeia methods. NIH was more suitable for the MICA method of Chinese Pharmacopoeia, and ICR for the PSPT method of European Pharmacopoeia.

Evaluating patients with autoimmune hemolytic anemia in the transfusion service and immunohematology reference laboratory: pretransfusion testing challenges and best transfusion-management strategies

The serologic evaluation of autoimmune hemolytic anemia (AIHA) confirms the clinical diagnosis, helps distinguish the type of AIHA, and identifies whether any underlying alloantibodies are present that might complicate the selection of the safest blood for any needed transfusion. The spectrum of testing is generally dependent on the amount and class (immunoglobulin G or M) of autoantibody as well as the resources and methodologies where testing is performed. The approach may range from routine pretransfusion testing, including the direct antiglobulin test, to advanced techniques such as adsorptions, elution, and red cell genotyping. When transfusion is needed, the selection of the optimal unit of red blood cells is based on urgency and whether time allows for the completion of sophisticated serologic and molecular testing methods. From the start of when AIHA is suspected until the completion of testing, communication among the clinical team and medical laboratory scientists in the transfusion service and immunohematology reference laboratory is critical as testing can take several hours and the need for transfusion may be urgent. The frequent exchange of information including the patient's transfusion history and clinical status, the progress of testing, and any available results is invaluable for timely diagnosis, ongoing management of the patient, and the safety of transfusion if required before testing is complete.

Prevalence of syphilis and chlamydia trachomatis infection among men who have sex with men in Jiangsu province, China: A cross-sectional survey.

BackgroundEpidemics of sexually transmitted infections (STIs) among men who have sex with men (MSM) are major global public health concerns. This study aimed to examine the prevalence of syphilis and chlamydia trachomatis (CT) infection and associated factors among MSM in Jiangsu province, China, hoping to provide updated data for the formulation of relevant policies.MethodsA cross-sectional survey was conducted among MSM from April to July 2021 in four cities in the province. Socio-demographic characteristics and behavioral information were collected through a face-to-face questionnaire interview. Venous blood specimens were collected for HIV, hepatitis C (HCV), and syphilis testing using serological testing methods. First-void urine specimens were collected for CT and Neisseria gonorrhoeae (NG) testing using nucleic acid amplification testing (NAAT) methods. Chi-square tests were used to compare differences in syphilis and CT infection between subgroups of variables. Multivariate logistic regression analysis was used to identify factors associated with syphilis and CT infection.ResultsA total of 1,087 participants were enrolled. The prevalence of HIV, HCV, syphilis, CT and NG infection were 6.6, 0.4, 6.3, 4.2, and 0.4%, respectively. MSM recruited online [adjusted odds ratio (aOR) = 2.189, P = 0.020], diagnosed with an STI in the past 12 months (aOR = 3.304, P < 0.001), and living with HIV (aOR = 4.721, P < 0.001) were more likely to have syphilis infection. MSM who were younger than 25 years (aOR = 4.286, P = 0.020), had senior high school level education (aOR = 2.521, P = 0.038), and were recruited via VCT clinics (aOR = 3.455, P = 0.001) were more likely to have CT infection.ConclusionsOur study showed a high prevalence of syphilis and chlamydia among MSM in Jiangsu province, China. STI screening, diagnosis, and treatment services promotion should be a top priority on the prevention agenda.

Profil Titer Antibodi Avian Influenza Pada Ayam Layer Di Kandang Sistem Terbuka Dan Tertutup

The aim of this research was to determine the antibody titer results for laying hens Avian Influeza (AI) and CV (Coefficient of variance) in open and close houses. This research took place at the Bukit Limestone laying hens farm which is located in Talun, Blitar Regency, East Java. The sample of this study was randomly selected from each cage with the number of each cage being 30 test samples. Blood samples were taken through the brachial vein which is located on the inside of the chicken wing. Titer examination was carried out using the HI test (Hemagglutation inhibition) serological test method at the serological test laboratory of PT Akurat Diagnostik Indonesia. Based on this comparative descriptive research, the method used to analyze the data is the Mann-Whitney test and using SPSS. In closed house cages, the average AI antibody titer is 24.03 while in open house cages, the average AI antibody titer is 25.30. Chickens with an average antibody titer of &gt; 24 were classified as protective against Avian Influenza. The test results showed no significant difference in AI antibody titers in closed house and open house cages.&#x0D;

Specificity and Confirmation of SARS-CoV-2 Serological Test Methods in Emergency Department Populations Across the United States in 2019 and Early 2020.

BackgroundSerological testing for SARS-CoV-2 is integral for understanding prevalence of disease, tracking of infections, confirming humoral response to vaccines, and determining timing and efficacy of boosters. The study objective was to compare the specificity of serology assays in emergency department populations across the United States in 2019 (pre-pandemic) and early 2020, incorporating an automated confirmatory assay.MethodsPatient specimens (n = 1954) were from 4 regions in the United States: New York, NY; Milwaukee, WI; Miami, FL; and Los Angeles, CA. Specimens were tested with SARS-CoV-2 anti-spike receptor-binding domain assays: SARS-CoV-2 IgG on the Abbott Alinity i (AdviseDx SARS-Cov-2 IgG II) and Beckman Coulter Access 2 (SARS-CoV-2 IgG II), and SARS-CoV-2 IgM on the Abbott Alinity i (AdviseDx SARS-CoV-2 IgM). Reactive samples were tested with a research use only angiotensin-converting enzyme 2 binding inhibition assay (Abbott ARCHITECT) for confirmation of SARS-CoV-2 neutralizing antibodies. Assay specificity was determined and comparisons performed with Fisher’s exact test.ResultsOverall SARS-CoV-2 IgG specificity was 99.28% (95% confidence interval, 98.80%–99.61%), 99.39% (98.93%–99.68%), and 99.44% (98.99%–99.72%) for SARS-CoV-2 IgG by Abbott and Beckman, and SARS-CoV-2 IgM, respectively. Overall agreement for the two IgG assays was 99.28% (range for the 4 sites: 98.21% to 100%). There were no specificity differences between assays or sites.ConclusionsThe specificity of the serological assays evaluated in a large, diverse emergency department population was >99% and did not vary by geographical site. A confirmatory algorithm with an automated pseudo-neutralization assay allowed testing on the same specimen while reducing the false positivity rate and increasing the value of serology screening methods.

HRP-conjugated-nanobody-based cELISA for rapid and sensitive clinical detection of ASFV antibodies.

African swine fever (ASF), which is caused by the ASF virus (ASFV), is a highly contagious hemorrhagic disease that causes high mortality to domestic porcine and wild boars and brings huge economic losses to world swine industry. Due to the lack of an effective vaccine, the control of ASF must depend on early, efficient, and cost-effective detection and strict control and elimination strategies. Traditional serological testing methods are generally associated with high testing costs, complex operations, and high technical requirements. As a promising alternative diagnostic tool to traditional antibodies, nanobodies (Nb) have the advantages of simpler and faster generation, good stability and solubility, and high affinity and specificity, although the system is dependent on the immunization of Bactrian camels to obtain the specific VHH library of the target protein. The application of Nbs in the detection of ASFV antibodies has not yet been reported yet. Using a phage display technology, one Nb against the ASFV p54 protein that exhibited high specificity and affinity, Nb8, was successfully screened. A HEK293T cell line stably expressing Nb8-horseradish peroxidase (HRP) fusion protein was established using the lentiviral expression system. Following the optimization of the reaction conditions, the Nb8-HRP fusion protein was successfully used to establish a competitive enzyme-linked immunosorbent assay (cELISA) to detect ASFV-specific antibodies in pig serum, for the first time. There was no cross-reaction with healthy pig serum, porcine pseudorabies virus (PRV), porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV), porcine epidemic diarrhea virus (PEDV), and classical swine fever virus (CSFV) positive sera. The optimal cut-off value for the cELISA by ROC analysis was 52.5%. A total of 209 serum samples were tested using the developed cELISA and a commercial ELISA kit. The results showed that the relative specificity of the cELISA was 98.97%, and the relative sensitivity of the cELISA was 93.3%, with the percent agreement between the two ELISA methods being 98.56%. In conclusion, a specific, sensitive, and repeatable cELISA was successfully developed based on the Nb8 as a probe, providing a promising method for the detection of anti-ASFV antibodies in clinical pig serum.Key points• We successfully screened a specific, high affinity nanobody against ASFV p54 protein.• We establish a method for continuous and stable expression of Nb-HRP fusion protein using a lentiviral packaging system.• We establish a nanobody cELISA detection method that can monitor an ASF infection.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00253-022-11981-4.

An update on Covid-19 serology

Since the onset of the SARS-CoV-2 pandemic, diagnosis of acute infection has predominantly been achieved using nucleic acid amplification. However, serological testing methods have retained utility in specific clinical and public health settings.

Application of metagenomic next-generation sequencing in the diagnosis of severe pneumonia caused by Chlamydia psittaci

PurposePsittacosis is a zoonotic infectious disease caused by the transmission of the bacterium Chlamydia psittaci (C. psittaci) from birds to humans. Infections in humans mainly present as community-acquired pneumonia (CAP). However, most cases are treated without diagnostic testing, and the importance of Chlamydia psittaci infection as a cause of CAP is therefore unclear. Diagnostic tools, including culture, serologic test, and PCR-based methods, are available but prone to false negative results. Metagenomic next-generation sequencing (mNGS) has been increasingly used in the diagnosis of infectious diseases, particularly when conventional diagnostic approaches have limitation.Detection of nucleic acid sequence of C. psittaci in respiratory tract samples by metagenomic next-generation sequencing (mNGS) is effective for early diagnosis of severe C. psittaci pneumonia. Timely treatment based on tetracycline can reduce unnecessary use of antibiotics and improve prognosis of patients with severe C. psittaci pneumonia.MethodsClinical data of thirteen patients with severe C. psittaci pneumonia diagnosed by mNGS were collected. Clinical manifestations, treatment and prognosis of patients were summarized.ResultsThe typical symptoms of pneumonia caused by C. psittaci include fever, headache, myalgia, cough, and dyspnea. In the current study, all patients met the criteria for severe C. psittaci pneumonia and received mechanical ventilation, including noninvasive mechanical ventilation (five/thirteen) and invasive mechanical ventilation (eight/thirteen). The findings showed that patients with C. psittaci pneumonia presented with normal or slightly increased leucocytes and procalcitonin, and high C-reactive protein levels. Computed tomography manifestations included consolidation of lung parenchyma, with air bronchogram and pleural effusion in some patients. mNGS analysis results were obtained within 48–72 h. Eleven patients fully recovered after targeted treatment, however, two patients died from secondary multidrug-resistant Pseudomonas aeruginosa infection.ConclusionsThe findings of the current study show that mNGS is effective in diagnosis of C. psittaci pneumonia, and has significant diagnosis value in patients with severe infection. Patients responds well to the timely use of appropriate antibiotics.

A practitioner's guide to understanding infectious disease diagnostics in the United Kingdom. Part 2: Serological diagnostic testing methods and diagnostic test result interpretation

SummaryThis article is the second in a review series about infectious disease diagnostics and summarises serological testing techniques, diagnostic test validation and result interpretation. It highlights the requirement for results to be interpreted with testing limitations in mind and in conjunction with the case's clinical presentation. With these foundations, the treating clinician should always be well placed to deal with equine infectious diseases.

Detection of anti-SARS-CoV-2 antibodies in dried blood spots utilizing manual or automated spot extraction and electrochemiluminescence immunoassay (ECLIA).

Serological test methods to detect anti‐SARS‐CoV‐2 antibodies represent a major measure to manage the pandemic caused by the coronavirus disease 2019 (COVID‐19). In this communication, test results obtained from minimal‐invasively collected dried blood spot (DBS) specimens, which can be sampled ‘at home’ without the need of medically trained personnel, are compared to conventionally collected venous blood samples. DBS samples were prepared for analysis either manually or by a card extraction robot, and electrochemiluminescence assay (ECLIA) characteristics, assay readout values as well as stability data covering a period of more than 200 days are provided. Constant anti‐SARS‐CoV‐2 antibody readouts of quality control DBS were obtained over the entire test period using DBS specimens stored under dry and dark conditions. In addition, test results obtained from individuals tested twice within 10 months post‐infection indicated a consistent presence of antibodies.

Assessment of knowledge, attitude and practice towards Covid-19 outbreak among dental students in Lucknow, India: Is it time for a syllabus revamp?

Background: Mankind has observed various pandemics, but COVID-19 outbreak has caused unprecedented human health consequences. Since, dentists are highly vulnerable to this infection, KAP of dental students towards the transmission and prevention plays an important role in disease control. Objectives: To assess andcompare the KAP towards Covid-19 crisis among BDS 1st year (pre-clinical) and 3rd year (clinical) dental students in Lucknow. Materials and Methods: This online cross-sectional survey was conducted in May 2020, during the initial lockdown phase. 200 students (100 each of BDS 1st year and 3rd year) from Babu Banarasi Das College of Dental Sciences, Lucknow were selected to participate in the study. A pre-tested, self-administered questionnaire was distributed online using google forms. The collected data was statistically analysed. Results and Conclusion: Third year students undergoing clinical training had better positive response in all terms of KAP towards COVID 19 crisis when compared to the 1st year students in preclinical stage. The findings about lack of basic knowledge about viral infections like common cold and serologic testing methods like RT PCR were highlights of this study and needs to be corrected immediately if we want to contain the spread of COVID-19 infection in India. We probably should sensitise the dental student population as they enter dental schools towards right KAP to corona crisis&amp; ensure preventive methods are followed to remove dental profession from the stigma of being super spreaders. This can be attained by making subtle changes in the current curricula. Key words: Covid-19, KAP, Dental students, Syllabus revamp

To Study the Effectiveness of Platelet Transfusion in Management of Dengue Patients in Tertiary Care Hospital

Background: Dengue has been emerging as rapidly spreading and dreaded mosquito borne disease caused by the bite of Aedes Aegypti Mosquito. Clinical features are variable and presents with Dengue fever or Dengue Hemorrhagic fever or more severe Dengue shock syndrome. Thrombocytopenia is presenting feature in in all Dengue cases and some often presents with bleeding. Platelet transfusions are given in patients with haemorrhagic symptoms. Present study thus aims to study the effectiveness of platelet transfusion in management of Dengue patients with Dengue haemorrhagic fever and Dengue shock syndrome. Results: In present study, a total of 20 patients were diagnosed as dengue confirmed cases by serological testing methods. Out of 20, 12 (60%) patients had dengue fever with platelet count in range of 50,000-80,000 per μl. Two patients with Dengue fever had Petechial spots with platelet count in range of 50,000 per μl and were given prophylactic Single Donor Platelet Transfusions. Eight patients (40%) presented with Dengue Haemorrhagic fever and platelet count of < 20,000 per μl. These patients were given single donor platelet transfusions. Six patients responded good with CCI of > 30,000 per μl and 2 patients recorded as non-responders. Conclusion: This study suggests that 25% Platelet transfusions are inappropriate. Platelet transfusions are more effective when it is given to patients with platelet count <20,000 per μl. Platelet transfusion should be given based on platelet count and hemorrhagic manifestations, as this decreases hospitalization of patients and complications of dengue.

Immunity certification for COVID-19: ethical considerations.

Restrictive measures imposed because of the coronavirus disease 2019 (COVID-19) pandemic have resulted in severe social, economic and health effects. Some countries have considered the use of immunity certification as a strategy to relax these measures for people who have recovered from the infection by issuing these individuals a document, commonly called an immunity passport. This document certifies them as having protective immunity against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the virus that causes COVID-19. The World Health Organization has advised against the implementation of immunity certification at present because of uncertainty about whether long-term immunity truly exists for those who have recovered from COVID-19 and concerns over the reliability of the proposed serological test method for determining immunity. Immunity certification can only be considered if scientific thresholds for assuring immunity are met, whether based on antibodies or other criteria. However, even if immunity certification became well supported by science, it has many ethical issues in terms of different restrictions on individual liberties and its implementation process. We examine the main considerations for the ethical acceptability of immunity certification to exempt individuals from restrictive measures during the COVID-19 pandemic. As well as needing to meet robust scientific criteria, the ethical acceptability of immunity certification depends on its uses and policy objectives and the measures in place to reduce potential harms, and prevent disproportionate burdens on non-certified individuals and violation of individual liberties and rights.

Diagnostic accuracy of serological tests and kinetics of severe acute respiratory syndrome coronavirus 2 antibody: A systematic review and meta-analysis.

This study aimed to assess the diagnostic test accuracy (DTA) of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) serological test methods and the kinetics of antibody positivity. Systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. We included articles evaluating the diagnostic accuracy of serological tests and the kinetics of antibody positivity. MEDLINE through PubMed, Scopus, medRxiv and bioRxiv were sources of articles. Methodological qualities of included articles were appraised using QUADAS-2 while Metandi performs bivariate meta-analysis of DTA using a generalized linear mixed-model approach. Stata 14 and Review Manager 5.3 were used for data analysis. The summary sensitivity/specificity of chemiluminescence immunoassay (CLIA), enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay (LFIA) were 92% (95% CI: 86%-95%)/99% (CI: 97%-99%), 86% (CI: 82%-89%)/99% (CI: 98%-100%) and 78% (CI: 71%-83%)/98% (95% CI: 96%-99%), respectively. Moreover, CLIA-based assays produced nearly 100% sensitivity within 11-15 days post-symptom onset (DPSO). Based on antibody type, the sensitivity of ELISA-total antibody, CLIA-IgM/G and CLIA-IgG gauged at 94%, 92% and 92%, respectively. The sensitivity of CLIA-RBD assay reached 96%, while LFIA-S demonstrated the lowest sensitivity, 71% (95% CI: 58%-80%). CLIA assays targeting antibodies against RBD considered the best DTA. The antibody positivity rate increased corresponding with DPSO, but there was some decrement when moving from acute phase to convalescent phase of infection. As immunoglobulin isotope-related DTA was heterogeneous, our data have insufficient evidence to recommend CLIA/ELISA for clinical decision-making, but likely to have comparative advantage over RT-qPCR in certain circumstances and geographic regions.

Establishment of measurement threshold and comparison of results for detection of Treponema pallidum specific antibody by Siemens ADVIACentaur XP chemiluminescent immunoanalyzer

To investigate the detection threshold of Treponema pallidum specific antibody method by chemiluminescent immunoassay (CLIA) in Siemens ADVIA Centaur XP for Syphilis serological test, and compare with the results derived from CMIA, TP-WB and TPPA method. The result can serve as reference for the application of CLIA. In total 30 887 samples screened by Treponema pallidum specific antibody method were collected by Abbott architect i2000 CMIA from July 2018 to July 2019 in Yanda Hospital of Hebei Province. We selected 153 patients with the ratio of sample absorbance to critical value (S/CO) of 1-9 by CMIA screening of Treponema pallidum specific antibody as the research objects. The reverse sequence of syphilis serological detection was adopted, and TP-WB and TPPA were used as the confirmation methods respectively. MedCalc software was used to analyze the results of ROC curve, and the cut-off value was obtained. Chi square test was used to test the difference significance of counting data. The detection results of Treponema pallidum specific antibody in the same batch of serum samples were unequal by different methods. There was no significant difference between CLIA method and TPPA method, but significant difference between CLIA method with TP-WB method and CMIA method was found. TPPA test results and TP-WB test results were taken as gold standards, ROC curve analysis showed that the best diagnostic cutoff value of CLIA method was 4.01 and 16.06, respectively, and the area under the curve was 0.961 and 0.838. The suggested cutoff value of CLIA method is quite different when using different syphilis serological test methods as the gold standard, Therefore, when the S/CO value determined by CLIA is between 1.00 to 16.06, TP-WB method should be recommended as the first choice in laboratory serological test for recheck and confirmation to avoid clinical misdiagnosis.

The application of metagenomic next-generation sequencing in diagnosing Chlamydia psittaci pneumonia: a report of five cases

BackgroundChlamydia psittaci pneumonia is a zoonotic infectious disease caused by Chlamydia psittaci. Diagnostic tools, including culture, serologic test and PCR-based methods, are available but prone to false negative results.Case presentationThis report included five cases of Chlamydia psittaci pneumonia. Symptoms and signs common to all 5 cases included fever, coughing, generalized muscle ache, and most notably, inflammatory infiltration of the lungs upon chest CT and X-ray. Metagenomic next-generation sequencing (mNGS) revealed the presence of Chlamydia psittaci in biopsy lung tissue in 3 cases and bronchoalveolar lavage fluid in the remaining 2 cases. Three patients responded to doxycycline plus moxifloxacin; two patients responded to moxifloxacin alone.ConclusionsmNGS could be used to diagnose Chlamydia psittaci pneumonia.

Overview of clinical guidelines on the management of hepatitis E

Perceptions of hepatitis E have transformed over the past decade. This infection was common only in some developing countries. It is known now that hepatitis E occurs in most high - income countries and is largely a zoonotic infection. The review analyzes the relevant key publications and recommendations on the diagnosis and treatment of hepatitis E. Theproblems of diagnosis, treatment and prevention of hepatitis E caused by genotypes 3 and 4 are highlighted. It is shown that with symptoms of acute hepatitis for hepatitis E virus infection (HEV) it is advisable to test not only travelers returning from areas endemic for 1 or 2 genotypes (Asia, Africa, Mexico) and pregnant women, but also all patients, after excluding other reasons for changing liver tests. Testing for HEV is also recommended for patients with chronic liver disease with unexplained deterioration, for patients with immunosuppression and changes of liver tests, for patients with systemic manifestations of diseases of the nervous system. A combination of serological testing and nucleic acid amplification methods are recommended for the diagnosis of HEV infection. Treatment of HEV infection includes the use of antiviral therapy in severe cases; if possible, for patients who underwent transplantation of solid organs - a reduction in doses of immunosuppressive drugs for pregnant women - intensive therapy. Prevention of HEV infection is aimed at people with chronic liver diseases and receiving immunosuppressive therapy who should be excluded from the use of mollusks and poorly fried pig, boar and deer meat.