Antigen Detection Assay Research Articles

Prevalence, Clinical Severity, and Serotype Distribution of Pneumococcal Pneumonia Among Adults Hospitalized With Community-Acquired Pneumonia in Tennessee and Georgia, 2018-2022.

Understanding the pneumococcal serotypes causing community-acquired pneumonia (CAP) is essential for evaluating the impact of pneumococcal vaccines. We conducted a prospective surveillance study of adults aged ≥18 years hospitalized with CAP at 3 hospitals in Tennessee and Georgia between 1 September 2018 and 31 October 2022. We assessed for pneumococcal etiology with cultures, the BinaxNOW urinary antigen detection test, and serotype-specific urinary antigen detection assays that detect 30 pneumococcal serotypes contained in the investigational pneumococcal conjugate vaccine V116, as well as licensed vaccines PCV15 and PCV20 (except serotype 15B). The distribution of pneumococcal serotypes was calculated based on serotype-specific urinary antigen detection results. Among 2917 hospitalized adults enrolled with CAP, 352 (12.1%) patients had Streptococcus pneumoniae detected, including 51 (1.7%) patients with invasive pneumococcal pneumonia. The 8 most commonly detected serotypes were: 3, 22F, 19A, 35B, 9N, 19F, 23A, and 11A. Among 2917 adults with CAP, 272 (9.3%) had a serotype detected that is contained in V116, compared to 196 (6.7%) patients with a serotype contained in PCV20 (P < .001), and 168 (5.8%) patients with a serotype contained in PCV15 (P < .001). A serotype contained in V116 but not PCV15 or PCV20 was detected in 120 (4.1%) patients, representing 38.0% of serotype detections. Approximately 12% of adults hospitalized with CAP had S. pneumoniae detected, and approximately one-third of the detected pneumococcal serotypes were not contained in PCV15 or PCV20. Development of new pneumococcal vaccines with expanded serotype coverage has the potential to prevent a substantial burden of disease.

Qualification of a 21-valent pneumococcal urine antigen detection assay and development of clinical positivity cutoffs.

Aim: Serotype-specific assays detecting pneumococcal polysaccharides in bodily fluids are needed to understand the pneumococcal serotype distribution in non-bacteremic pneumonia.Methods: We developed a urine antigen detection assay and using urine samples from adult outpatients without pneumonia developed positivity cutoffs for both a previously published 15-valent and the new 21-valent assay. Clinical sensitivity was confirmed with samples from patients with invasive pneumococcal disease.Results: Total assay precision ranged from 7.6 to 17.8% coefficient of variation while accuracy ranged between 80 and 150% recovery, except for three serotypes where recoveries ranged from 32 to 60%. Clinical sensitivity was 86.4% and specificity was 96.5% across all 30 serotypes.Conclusion: The assay could potentially assess serotype-distribution in non-infected and infected participants with pneumococcal disease.

Multicentric Study on the Clinical Mycology Capacity and Access to Antifungal Treatment in Portugal

The success of the clinical management of invasive fungal diseases (IFD) is highly dependent on suitable tools for timely and accurate diagnosis for effective treatment. An in-depth analysis of the ability of European institutions to promptly and accurately diagnose IFD was previously conducted to identify limitations and aspects to improve. Here, we evaluated and discussed the specific case of Portugal, for which, to our knowledge, there are no reports describing the national mycological diagnostic capacity and access to antifungal treatment. Data from 16 Portuguese medical institutions were collected via an online electronic case report form covering different parameters, including institution profile, self-perceived IFD incidence, target patients, diagnostic methods and reagents, and available antifungals. The majority of participating institutions (69%) reported a low-very low incidence of IFD, with Candida spp. indicated as the most relevant fungal pathogen, followed by Aspergillus spp. and Cryptococcus spp. All institutions had access to culture and microscopy, whereas 94 and 88% were able to run antigen-detection assays and molecular tests, respectively. All of the institutions capable of providing antifungal therapy declared to have access to at least one antifungal. However, echinocandins were only available at 85% of the sites. Therapeutic drug monitoring (TDM) was reported to remain a very restricted practice in Portugal, being available in 19% of the institutions, with the TDM of itraconazole and posaconazole performed in only 6% of them. Importantly, several of these resources are outsourced to external entities. Except for TDM, Portugal appears to be well-prepared concerning the overall capacity to diagnose and treat IFD. Future efforts should focus on promoting the widespread availability of TDM and improved access to multiple classes of antifungals, to further improve patient outcomes.

Trypanosoma cruzi antigen detection in blood to assess treatment efficacy and cure in mice models of Chagas disease.

Chagas disease (CD) is caused by the protozoan parasite Trypanosoma cruzi. Although endemic mainly in Latin America, CD has become a global public health problem due to migration of infected individuals to non-endemic regions. Despite progress made in drug development, preclinical assays for drug discovery are required to accelerate the development of new drugs with reduced side effects, which are much needed for human treatment. We used a cure model of infected mice treated with Fexinidazole (FZ) to further validate a novel Enzyme Linked Aptamer (ELA) assay that detects parasite biomarkers circulating in the blood of infected animals. The ELA assay showed cure by FZ in ~71% and ~77% of mice infected with the VL-10 and Colombiana strains of T. cruzi, respectively. The ELA assay also revealed superior treatment efficacy of FZ compared to Benznidazole prior to immunosuppression treatment. Our study supports the use of ELA assay as an alternative to traditional serology or blood PCR to assess the efficacy of antichagasic drugs during their preclinical phase of development. Further, the combination of high sensitivity and ease of use make this parasite antigen detection assay an attractive new tool to facilitate the development of much needed new therapies for CD.

Detection of Histoplasma capsulatum and Blastomyces dermatitidis antigens in serum using a single quantitative enzyme immunoassay.

Histoplasma and Blastomyces antigen detection assays are commonly used diagnostic tools. However, a high level of cross-reactivity between these antigens prevents definitive pathogen identification by these assays alone. Retrospective analysis of 3,529 patients with Histoplasma and Blastomyces antigen testing performed on the same serum sample yielded an overall percent agreement of 99.3% (3,506 of 3,529; kappa: 0.859) between the two assays, suggesting that use of a single assay to detect both antigens may be an alternative diagnostic approach. We assessed performance of the Gotham BioTech Blastomyces antigen (GBA) enzyme immunoassay (EIA) (Portland, Maine) for detection of Blastomyces and Histoplasma antigens in serum. Comparison to the MiraVista Diagnostics Blastomyces (MVB) EIA showed 100% positive (24 of 24), negative (57 of 57), and overall (81 of 81) percent agreement. Additionally, 171 sera were used to compare the GBA EIA to the MiraVista Diagnostics Histoplasma (MVH) EIA, which showed 91.3% (63 of 69), 98% (100 of 102), and 95.3% (163 of 171) positive, negative, and overall percent agreement, respectively. Among eight patients with discordant GBA/MVH EIA results, seven had additional fungal testing performed, and results suggested that the MVH and GBA results were inaccurate for two and five samples, respectively. Overall, this study suggests that the GBA EIA has a high level of agreement with both of the commonly used, individual Blastomyces and Histoplasma antigen EIAs. By taking advantage of the high level of cross-reactivity between Blastomyces and Histoplasma antigen EIAs, utilization of a single antigen detection assay for these fungi provides an opportunity to optimize test utilization and decrease patient cost while maintaining a high level of diagnostic accuracy.

Rapid detection of human influenza A viruses by HFman probe-based loop-mediated isothermal amplification assays

Since China abandoned the zero-COVID policy at the end of 2022, a wave of severe Flu pandemic emerged in China. Rapid and accurate diagnosis of Influenza A virus (IAV) is critical for clinical management and therapeutic decision-making of patients with fever. Here, we reported a novel IAV HF-LAMP assay, which can be performed with purified RNA or directly using clinical samples. The assays with purified RNA and clinical samples have high sensitivity with limit of detection (LOD) of 9.6 copies/reaction, 9900 copies/mL, and short sample-to-answer times of 36 and 50 min, respectively. Both assays showed high specificity and significantly higher IAV detection rate than the rapid antigen detection (RAD) assays. Furthermore, we found the vast majority (91.2 %) of children with fever during the pandemic were infected by IAV, and current IAV infection has a very narrow detectable window. The novel IVA HF-LAMP assays will provide robust tools to facilitate early diagnosis of IAV infection in current and future seasonal influenza epidemics.

Advancements in Therapeutic and Diagnostic Strategies for COVID-19: A Review of Recent Developments

The COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, has challenged healthcare systems worldwide, necessitating rapid advancements in therapeutic and diagnostic strategies. This review examines recent developments in the management of COVID-19, focusing on emerging treatments and diagnostic modalities. Therapeutic interventions, including antiviral agents, immunomodulators, monoclonal antibodies, and repurposed drugs, are evaluated for their mechanisms of action and clinical efficacy. Additionally, novel diagnostic techniques such as molecular testing, antigen detection assays, serological assays, and advanced imaging modalities are discussed in the context of COVID-19 diagnosis and surveillance. Through a comprehensive analysis of current literature and clinical trials, this review aims to elucidate the evolving landscape of COVID-19 management and inform future research directions and public health interventions.

Identification of biomarker candidates for filarial parasite infections by analysis of extracellular vesicles

BackgroundImproved diagnostic tools are needed for detecting active filarial infections in humans. Tests are available that detect adult W. bancrofti circulating filarial antigen, but there are no sensitive and specific biomarker tests for brugian filariasis or loiasis. Here we explored whether extracellular vesicles released by filarial parasites contain diagnostic biomarker candidates.MethodsVesicles were isolated using VN96-affinity purification from supernatants of short-term in vitro cultured B. malayi microfilariae (Mf) and analyzed by mass spectrometry (Bruker timsTOF). Parasite-specific proteins were identified by bioinformatic analysis and a protein was called present if supported by ≥ 2 spectra. After validation with cultures parasites, this approach was then used to analyze vesicles isolated from plasma of animals infected with B. malayi and from humans with heavy Loa loa infections.ResultsVesicles from Mf cultures contained more than 300 B. malayi proteins with high consistency across biological replicates. These included the known Mf excretory antigen BmR1 (AF225296). Over 150 B. malayi proteins were detected in vesicles isolated from plasma samples from two infected animals. Vesicles isolated from plasma from 10 persons with high L. loa Mf densities contained consistently 21 proteins, 9 of them were supported by at least 5 unique peptides and 7 with spectral counts above 10. The protein EN70_10600 (an orthologue of the B. malayi antigen BmR1, GenBank AF225296) was detected in all 10 samples with a total count of 91 spectra and a paralogue (EN70_10598) was detected in 6 samples with a total of 44 spectra.DiscussionExtracellular vesicles released by filarial parasites in vitro and in vivo contain parasite proteins which can be reliably detected by mass spectrometry. This research provides the foundation to develop antigen detection assays to improve diagnosis of active filarial infections in humans.

Development of a specific MPXV antigen detection immunodiagnostic assay.

Human monkeypox (mpox) has recently become a global public health emergency; however, assays that detect mpox infection are not widely available, largely due to cross-reactivity within the Orthopoxvirus genus. Immunoassay development was largely confined to researchers who focus on biothreats and endemic areas (Central and West Africa) until the 2022 outbreak. As was noted in the COVID-19 pandemic, antigen detection assays, integrated with molecular assays, are necessary to help curb the spread of disease. Antigen-detecting immunoassays offer the advantage of providing results ranging from within min to h and in lateral flow formats; they can be deployed for point-of-care, home, or field use. This study reports the development of an mpox-specific antigen detection immunoassay developed on a multiplexed, magnetic-bead-based platform utilizing reagents from all research sectors (commercial, academic, and governmental). Two semi-quantitative assays were developed in parallel and standardized with infectious mpox virus (MPXV) cell culture fluid and MPXV-positive non-human primate (NHP) sera samples. These assays could detect viral antigens in serum, were highly specific toward MPXV as compared to other infectious orthopoxviruses (vaccinia virus, cowpox virus, and camelpox virus), and exhibited a correlation with quantitative PCR results from an NHP study. Access to a toolbox of assays for mpox detection will be key for identifying cases and ensuring proper treatment, as MPXV is currently a global traveler.

Multicountry Review of Streptococcus pneumoniae Serotype Distribution Among Adults With Community-Acquired Pneumonia.

Nonbacteremic community-acquired pneumonia (CAP) is a leading presentation of severe pneumococcal disease in adults. Serotype-specific urinary antigen detection (UAD) assay can detect serotypes causing pneumococcal CAP, including nonbacteremic cases, and guide recommendations for use of higher valency pneumococcal conjugate vaccines (PCVs). Adult CAP serotype distribution studies that used both Pfizer UADs (UAD1, detects PCV13 serotypes; UAD2, detects PCV20 non-PCV13 serotypes plus 2, 9N, 17F, and 20) were identified by review of an internal study database and included if results were published. The percentages of all-cause radiologically confirmed CAP (RAD + CAP) due to individual or grouped (PCV13, PCV15, and PCV20) serotypes as detected from culture or UAD were reported. Six studies (n = 2, United States; n = 1 each, Germany, Sweden, Spain, and Greece) were included. The percentage of RAD + CAP among adults ≥18 years with PCV13 serotypes equaled 4.6% to 12.9%, with PCV15 serotypes 5.9% to 14.5%, and with PCV20 serotypes 7.8% to 23.8%. The percentage of RAD + CAP due to PCV15 and PCV20 serotypes was 1.1-1.3 and 1.3-1.8 times higher than PCV13 serotypes, respectively. PCV13 serotypes remain a cause of RAD + CAP among adults even in settings with pediatric PCV use. Higher valency PCVs among adults could address an important proportion of RAD + CAP in this population.

Evaluation of a Rapid Urine Antigen Detection Assay as a Point-of-Care Test in the Diagnosis of Community-Acquired Pneumonia.

Introduction Community-acquired pneumonia (CAP) is among the most common public health problems encountered throughout the world. CAP is a frequent cause of lower respiratory tract infections among children and geriatric-age persons. The etiology of CAP is complex but generally involves infection with bacteria likeStreptococcus pneumoniae (S. pneumoniae), which is the most common cause of CAP. The underdiagnosis of CAP due to the limitations of conventional culture methods could be responsible for severe morbidity and mortality, especially among susceptible populations.We evaluated the usefulness of a rapid immunochromatographic test (BinaxNOW™, Abbott, Chicago, IL) that detects S. pneumoniae through a rapid urine antigen test (RUAT) as a point-of-care (POC) diagnostic method in the early detection of CAP. Methods A prospective study was conducted in a university-affiliated teaching hospital between January 2019 and September 2019 (nine months). The study recruited 300 inpatients who revealed signs and symptoms associated with pneumonia. The study was approved by the institutional ethics committee, and all participants provided their voluntary informed consent.Laboratory evaluationincluded the collection of sputum samples, which were processed for Gram stain and routine culture. Five milliliters of blood were collected from all the subjects for carrying out a blood culture. A urine sample was collected from each participant for the detection of S. pneumoniae through the point-of-care urinary antigen test. Results Of the 300 patients diagnosed with CAP, the S. pneumoniae RUAT was positive in 110 out of 140 cases of pneumococcal pneumoniae (78.57%). The RUAT results were positive for 20 (66.6%) out of 30 bacteremic patients and for 90 (81.8%) out of 110 patients positive for sputum culture. The RUAT was positive in 10 out of 20 cases of pneumonia with an unknown microbial etiology. The overall sensitivity (78.57%), specificity (100%), positive predictive value (100%), negative predictive value (98.88%), and accuracy (90%) of the RUAT were similar to sputum culture results. Conclusion The RUAT has shown comparable efficacy with sputum culture and therefore can be used as a complementary approach to conventional methods in the early diagnosis of CAP caused byS. pneumoniae.Due toits ease of use andrapid results, it could be incorporated as a POC diagnostic test.

The serotype-specific prevalence of pneumococci in hospitalized pneumonia patients with COPD: a prospective, multi-center, cohort study.

The overall incidence of pneumococcal pneumonia is declining. However, the change in the pathogenic distribution of community-acquired pneumonia (CAP) in chronic obstructive pulmonary disease (COPD) patients and the serotype specificity of Streptococcus pneumoniae have not been evaluated in the post-era of pneumococcal vaccination in Korea. We conducted a prospective, multi-center, cohort study from seven University-affiliated hospitals. The primary objective was the identification of serotype-specific prevalence of pneumococcal pneumonia in COPD patients hospitalized for CAP. For the purpose, we conducted serotype-specific urine antigen detection (SS-UAD) assays for S. pneumoniae. The secondary objectives were other clinical characteristics of pneumonia including vaccination status. The total number of participants was 349. Most of them were male (95.1%) with old ages (75.55 ± 8.59 y). The positive rate for S. pneumoniae was 9.2% with SS-UAD assay and the common serotypes were 22F, 6A, and 6B. In the sputum, Pseudomonas aeruginosa (5.0%) and Haemophilus influenzae (4.0%) were common pathogens. The vaccination rate was 78.8%, 53.0%, and 25.8% for influenza, pneumococcal polysaccharide vaccine 23 (PPV 23), and pneumococcal protein- conjugated vaccine 13 (PCV 13), respectively. Thirteen patients died during hospitalization (mortality rate; 3.7%). There was no difference in the respective rate of influenza vaccination (79.2% vs. 69.2%, p = 0.288) and PCV 13 vaccination (25.6% vs. 30.8%, p = 0.443) between survivors and the deceased. Serotypes 22F, 6A, and 6B, which are covered either by PPV 23 or by PCV 13, are still common pneumococcal serotypes in COPD pneumonia in the post-vaccination era in Korea.

A COMPARATIVE STUDY OF RAPID SARS COV 2 ANTIGEN DETECTION TEST &amp; REAL TIME PCR TEST FOR DIAGNOSIS OF COVID-19 IN TERTIARY CARE INSTITUTE AT KOTA, SOUTH-EAST RAJASTHAN, INDIA

Background:The 2019 (Covid19) pandemic of coronavirus disease was caused by SARS Cov 2 Virus. The emergence of the disease was started from the Wuhan city of China in December 20191. This infection causes asymptomatic and mild diseases more than severe pneumonia. A Rapid Lateral flow immunoassays using monoclonal anti-SARS CoV- 2 antibodies, targeting SARS-CoV-2 antigens, can be used as complementary screening tests if their accuracy comes comparable to that of gold standard real-time RT-PCR assays. Objective:The present study has been conducted retrospectively on the data of patients who underwent for Covid 19 diagnosis by RAT at the Microbiology Department Central Laboratory, Maharao Bhim Singh Hospital Nayapura Kota. Material and Method: Respiratory samples from suspected 5219 COVID-19 patients, mainly nasopharyngeal and throat swabs were collected. COVID-19 Ag Confirmit™ kit (Alpine biomedicals) is a rapidchromatographic immunoassay for the detection ofSARS-CoV-2 nucleoprotein (N) antigen in respiratoryspecimens. Multiplex Real-time RT-PCR kit (TRIVITRON healthcare) was used, whichtargets envelope gene (E), and Orf1ab gene of SARS-CoV-2 genome and RPP30 Human gene as internal control, was used for SARS-CoV-2RNA detection. Descriptive statistics were used to describe the usefulness of rapid diagnostic tests. For that online MedCalcs Diagnostic test evaluation statistical tool10. Result: Among all 5219 samples (n=5219) tested by RT-PCR 785 (15.4%) samples were positive and 4434 (84.95%) were negative. Samples tested by RAT 813 (15.57%) samples were positive &amp; 4406 (84.42%) were negative, in our study we found discordant results in 36 samples. The sensitivity and specificity of the COVID-19 Ag Confirmit™ kit (Alpine biomedicals) were 99.49% and 99.28% respectively. Discussion: Out of 785 RT-PCR-positive samples in our study, the 4 false negative results were tested for SARS-CoV-2 antigen seven days after disease onset. The RT-PCR result of these samples had relatively high Ct-values. Without the present population prevalence of COVID-19, the positive and negative predictive values (PPV and NPV) of the assay could not be accurately calculated. Conclusions: There is comparable Sensitivity and Specificity between Rapid assay for SARS-CoV-2 antigen detection (COVID-19 Ag Confirmit™ kit) and real-time RT-PCR assay.

Antigen-Based Diagnosis of Human Giardiasis: A Systematic Review and Meta-Analysis.

We aimed to present a systematic review and meta-analysis of studies that used antigen-based assays for the diagnosis of human giardiasis. All the related published literature cited within PubMed, ISI web of science, Google Scholar, Embase, and Scopus, were searched up to December 2021. The search terms, both as MeSH terms and text words, were "Giardia", "Giardia lamblia", "Giardia intestinalis", "giardiasis", combined with "diagnosis", "antigen detection", serodiagnosis, or serological diagnosis. The required data was extracted from the papers. Pooled estimates of sensitivity and specificity were obtained and forest plots and summary receiver operating characteristics (SROC) plots were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The search of databases found 1683 papers, of which 46 articles fulfilled our eligibility criteria. The sensitivity of antigen-based methods for the diagnosis of human giardiasis ranged from 45% (95% CI: 31-59%) to 100% (95% CI: 100-100%) and the pooled estimate of sensitivity was 92% (95% CI: 90-93%). The pooled estimated specificity was 97% (95% CI: 96-98%), ranged from 81% (95% CI: 68-89%) to 100% (95% CI: 98-100%). The summary estimate of PPV and NPV were 92 % (95% CI: 90-93%) and 97% (95% CI: 96-98%) respectively. Comparing the performance of the antigen detection assays by region revealed a significant difference in the assay's performances in different regions of the world. The antigen-based detection methods have acceptable and satisfactory performance in the diagnosis of human giardiasis. The task ahead is to identify more specific target antigens and design simpler, cheaper, and more sensitive methods for the diagnosis of this common worldwide-distributed parasitic infection.

Performance evaluation of SARS-CoV-2 antigen detection in the post-pandemic era: multi-laboratory assessment.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen detection is an indispensable tool for epidemic surveillance in the post-pandemic era. Faced with irregular performance, a comprehensive external quality assessment (EQA) scheme was conducted by the National Center for Clinical Laboratories (NCCL) to evaluate the analytical performance and status of SARS-CoV-2 antigen tests. The EQA panel included ten lyophilized samples containing serial 5-fold dilutions of inactivated SARS-CoV-2-positive supernatants of the Omicron BA.1 and BA.5 strains and negative samples, which were classified into "validating" samples and "educational" samples. Data were analyzed according to qualitative results for each sample. A total of 339 laboratories in China participated in this EQA scheme, and 378 effective results were collected. All validating samples were correctly reported by 90.56 % (307/339) of the participants and 90.21 % (341/378) of the datasets. The positive percent agreement (PPA) was >99 % for samples with concentrations of 2×107 copies/mL but was 92.20 % (697/756) for 4×106 copies/mL and 25.26 % (382/1,512) for 8×105 copies/mL samples. Colloidal gold was the most frequently used (84.66 %, 320/378) but showed the lowest PPAs (57.11 %, 1,462/2,560) for positive samples compared with fluorescence immunochromatography (90 %, 36/40) and latex chromatography (79.01 %, 335/424). Among 11 assays used in more than 10 clinical laboratories, ACON showed a higher sensitivity than other assays. The EQA study can help to validate whether it's necessary to update antigen detection assays for manufacturers and provide participants with information about the performance of assays to take the first step toward routine post-market surveillance.

A novel immuno-molecular strategy for the detection of Streptococcus pneumoniae serotypes in human cerebrospinal and middle ear fluids

Streptococcus pneumoniae is one of the most common microorganisms causing acute otitis media (AOM) in children. While bacterial culture of middle ear fluid (MEF) is the gold standard to detect the etiological organisms, several host and pathogen factors impact the survival of the organisms resulting in false negatives. To overcome this limitation, we have developed and validated an innovative multiplex immuno-molecular assay to screen and detect the S. pneumoniae 15-valent pneumococcal conjugate vaccine (PCV15; STs 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F, and 33F) vaccine serotypes in MEF. This novel in vitro approach involves two-step testing. First, the MEF specimens were tested for highly conserved pneumococcal genes, autolysin, lytA, and pneumolysin, ply using direct PCR to identify pneumococcus positive specimens. The pneumococcus positive specimens were screened for the presence of vaccine serotype specific pneumococcal polysaccharides using a 15-plex Pneumococcal Antigen Detection (PAD) assay, with specific capture and detection monoclonal antibodies. Due to the lack of availability of MEF samples, cerebrospinal fluid (CSF) was used as the surrogate matrix for the development and validation of the PCR-PAD assays. The PCR and PAD assays were separately evaluated for sensitivity and specificity. Subsequently, the PCR-PAD assays were cross-validated with human MEF samples (n = 39) which were culture confirmed to contain relevant bacterial strains. The combined PCR-PAD assays demonstrated high rate of agreement 94.9% (95% CI; 82.7, 99.4%) with historical Quellung serotype data of these MEF samples. This novel PCR-PAD assay demonstrates the feasibility of combining molecular and immunological assays to screen and identify PCV15 pneumococcal vaccine serotypes in AOM clinical samples.

Community-Acquired Pneumonia Incidence in Adults Aged 18 Years and Older in Goto City, Japan: A Prospective Population-Based Study

Community-Acquired Pneumonia Incidence in Adults Aged 18 Years and Older in Goto City, Japan: A Prospective Population-Based Study

MPT51 and MPT64-based antigen detection assay for the diagnosis of extrapulmonary tuberculosis from urine samples

In view of WHO's “End-TB” strategy, we developed a non-invasive, urine-based ELISA, targeting 2 Mycobacterium tuberculosis antigens namely MPT51 and MPT64 for extrapulmonary TB (EPTB) diagnosis. Suspected EPTB patients (n = 137) [Pleural TB, Abdominal TB and Tuberculous meningitis] were categorized in “Definite” EPTB (n = 10) [Xpert-MTB/RIF and/or culture-positive], “Probable” EPTB (n = 77) and “Non-EPTB” (n = 50) groups using defined composite reference standards. ROC-curves were generated using ELISA results of “Definite” EPTB and “Non-EPTB” groups for both antigens independently and cut-off values were selected to provide 86.3% (95%CI:73.3–94.2) specificity for MPT51 and 92% (95%CI:80.8–97.8) for MPT64. The sensitivity of MPT51-ELISA and MPT64-ELISA was 70% (95%CI:34.7–93.3) and 90% (95%CI:55.5–99.7) for “Definite” EPTB group and 32.5% (95%CI:22.2–44.1) and 30.8% (95%CI:20.8–42.2) for “Probable” EPTB group, respectively. Combining the results of both ELISAs showed a 100% (95%CI:69.1–100) sensitivity in “Definite” EPTB group and 41.6% (95%CI:30.4–53.4) in “Probable” EPTB group, with an 80% (95%CI:66.3–89.9) specificity. The results demonstrated the potential of urine-based ELISAs as screening tests for EPTB diagnosis.

Role of recombinant Histoplasma capsulatum 100-kilodalton antigen in the diagnosis of histoplasmosis among HIV/AIDS patients: Antigenuria and antibodies detection.

Diagnosing progressive disseminated histoplasmosis (PDH) is still challenging in many countries where this disease is highly endemic. Definitive diagnosis is established by culture and/or by cytology/histopathology but both procedures have limited sensitivity and cultures are time-consuming. Antibodies detection by immunodiffusion has a low sensitivity in immunocompromised individuals. Commercially available antigen detection assays have high sensitivity in PDH cases; however, they are expensive and only performed in few laboratories. To describe the potential use of a novel ELISA for antibodies testing and a dot blot assay for antigen testing for diagnosing PDH using the recombinant 100 kDa protein of Histoplasma capsulatum (Hcp100) and their polyclonal antibodies as novel reagents, respectively. Serum and urine samples from a cohort of patients with HIV/AIDS and proven PDH were studied for the detection of anti-Hcp100 antibodies by ELISA and Hcp100 antigen by dot blot, respectively. Sensitivity, specificity and cross-reactions with other diseases were estimated for each assay and compared with those obtained using histoplasmin (HMN) as a reagent for antibodies detection by ELISA and immunodiffusion, and using a commercial antigenuria test. Antibodies detection by the Hcp100 ELISA demonstrated 78.6% sensitivity and 88.4% specificity, versus 85.7% sensitivity and 81.0% specificity for the HMN ELISA and 26.1% sensitivity and 100% specificity for the immunodiffusion assay. Antigen detection by the Hcp100 dot blot demonstrated 89.3% sensitivity and 97.0% specificity versus 82.1% sensitivity and 90.9% specificity for the commercial test. The immunoassays described herein based on Hcp100 would be a valuable screening tool for diagnosing PDH.

Radiographically confirmed community-acquired pneumonia in hospitalized adults due to pneumococcal vaccine serotypes in Sweden, 2016-2018-The ECAPS study.

In Sweden, pneumococcal serotype distribution in adults with community-acquired pneumonia (CAP) and potential coverage of currently licensed pneumococcal conjugate vaccines (PCVs) is unknown. During 2016-2018, patients aged ≥18 years hospitalized with radiologically confirmed (RAD+) CAP were enrolled at Skåne University Hospital in a study on the etiology of CAP in Sweden (ECAPS). Urine samples and blood cultures were collected per-protocol. Streptococcus pneumoniae (Spn) culture isolates were serotyped and urine samples tested for the pan-pneumococcal urinary antigen (PUAT) and multiplex urine antigen detection (UAD) assay, detecting 24 serotypes. Analyses included 518 participants with RAD+CAP; 67.4% were ≥65 years of age, 73.4% were either immunocompromised or had an underlying chronic medical condition. The proportion of CAP due to Spn identified by any method was 24.3% of which 9.3% was detected by UAD alone. The most frequently identified serotypes were 3 (26 cases, 5.0% of all CAP), and 8, 11A and 19A (10 cases each, 1.9%). In individuals aged 18-64 and ≥65 years, respectively, PCV20 serotypes contributed to 35 of 169 (20.7%) and 53 of 349 cases of all CAP (15.2%), and PCV13 serotypes caused 21 of 169 (12.4%) and 35 of 349 (10.0%) cases. PCV15 coverage was 23 of 169 (13.6%) and 42 of 349 (12.0%) in individuals aged 18-64 and ≥65 years, respectively. Overall, PCV20 increases the coverage of all CAP from 10.8% (PCV13) to 17.0%. Compared to earlier pneumococcal vaccines, PCV20 expands the coverage of all-cause CAP. Routine diagnostic tests underestimate the proportion of CAP caused by Spn.