Search Results (540)

Background and Objectives: A correct diagnosis of beta-hemolytic group A streptococcus (GAS)-pharyngitis allows the prevention of complications and unnecessary use of antibiotics. The aim of this study was to assess the management of pediatric GAS-pharyngitis in Romanian general practitioners (GPs)’ practice. Material and Methods: a cross-sectional study was conducted using a questionnaire distributed to Romanian GPs. Results: In total, 56 GPs completed the questionnaire, mostly females (83.9%, n = 47) from an urban area (60.7%, n = 34). They treated 5–10 (35.7%) or more than 10 (32.1%) cases of GAS monthly and considered white exudate on tonsils (92.9%, n = 52) to be the most suggestive clinical sign. Of the GPs, 25% (n = 14) used the Centor Criteria, 10.7% (n = 6) performed a rapid antigen detection test, and 42.9% (n = 24) requested throat culture for diagnosis. The younger GPs used the Centor Criteria significantly more often (p = 0.027) than the older ones. Most GPs (69.6%, n = 39) preferred targeted antibiotic therapy. Amoxicillin-clavulanate was the most commonly used antibiotic (55.4%, n = 31). Most GPs preferred oral antibiotics (89%, n = 50) for 10 days (55.4%, n = 31). Conclusions: Antibiotic treatment was initiated mostly based on clinical symptoms and in a short-course therapy. GPs stated that they prefer targeted antibiotic therapy, but they did not use proper diagnostic tools. Full article

Extrapulmonary tuberculosis (EPTB) remains diagnostically challenging due to its paucibacillary nature and variable presentation. Xpert and culture are limited in EPTB diagnosis due to sampling challenges, low sensitivity, and long turnaround times. This study evaluated the performance of the MPT64 antigen detection test for diagnosing EPTB, particularly tuberculous lymphadenitis (TBLN) and tuberculous pleuritis (TBP), in a high-TB, low-HIV setting. Conducted at Gulab-Devi Hospital, Lahore, Pakistan, this study evaluated the MPT64 test’s performance against conventional diagnostic methods, including culture, histopathology, and the Xpert MTB/RIF assay. Lymph node biopsies were collected, and cell blocks were made from aspirated pleural fluid from patients clinically presumed to have EPTB. Of 338 patients, 318 (94%) were diagnosed with EPTB. For TBLN, MPT64 demonstrated higher sensitivity (84%) than Xpert (48%); for TBP, the sensitivity was 51% versus 7%, respectively. Among histopathology-confirmed TBLN cases, MPT64 outperformed both culture and Xpert (85% vs. 58% and 47%). Due to the low number of non-TB cases, specificity could not be reliably assessed. The MPT64 test shows promise as a rapid, sensitive diagnostic tool for EPTB, particularly TBLN, in routine settings. While sensitivity is notably superior to Xpert, further studies are needed to evaluate its specificity and broader diagnostic utility. Full article

Nipah virus (NiV) and Hendra virus (HeV), which both belong to the genus henipavirus, are zoonotic pathogens that cause severe systemic, neurological, and/or respiratory disease in humans and a variety of mammals. Therefore, monitoring viral prevalence in natural reservoirs and rapidly diagnosing cases of henipavirus infection are critical to limiting the spread of these viruses. Current laboratory methods for detecting NiV and HeV include virus isolation, reverse transcription quantitative real-time PCR (RT-qPCR), and antigen detection via an enzyme-linked immunosorbent assay (ELISA), all of which require highly trained personnel and specialized equipment. Here, we describe the development of a point-of-care customized immunochromatographic lateral flow (ILF) assay that uses recombinant human ephrin B2 as a capture ligand on the test line and a NiV-specific monoclonal antibody (mAb) on the conjugate pad to detect NiV and HeV. The ILF assay detects NiV and HeV with a diagnostic specificity of 94.4% and has no cross-reactivity with other viruses. This rapid test may be suitable for field testing and in countries with limited laboratory resources. Full article

Heavy metal ions pose a significant threat to the environment and human health due to their high toxicity and bioaccumulation. Traditional instrumentations, although sensitive, are often complex, costly, and unsuitable for on-site rapid detection of heavy metal ions. Lateral flow assay technology has emerged as a research hotspot due to its rapid, simple, and cost-effective advantages. This review summarizes the applications of lateral flow assay technology based on nucleic acid molecules and antigen–antibody interactions in heavy metal ion detection, focusing on recognition mechanisms such as DNA probes, nucleic acid enzymes, aptamers, and antigen–antibody binding, as well as signal amplification strategies on lateral flow testing strips. By incorporating these advanced technologies, the sensitivity and specificity of lateral flow assays have been significantly improved, enabling highly sensitive detection of various heavy metal ions, including Hg²⁺, Cd²⁺, Pb²⁺, and Cr³⁺. In the future, the development of lateral flow assay technology for detection of heavy metal ions will focus on multiplex detection, optimization of signal amplification strategies, integration with portable devices, and standardization and commercialization. With continuous technological advancements, lateral flow assay technology will play an increasingly important role in environmental monitoring, food safety, and public health. Full article

Although vaccine development has primarily focused on inducing neutralizing antibodies, increasing evidence supports an important role of CD8⁺ T cell responses in vaccine effectiveness. Routine assays, which are mainly based on antibody titers, may therefore not accurately reflect the full immune response elicited by vaccination. Assessing antigen-specific T cell responses upon vaccination poses several challenges. A common issue in studying T cells specific to a vaccine antigen is their low frequency in circulation, which can limit their ex vivo analysis. Moreover, the use of human cell-based models is crucial for studying and optimizing the induction of T cell responses to design effective vaccines. We developed an innovative in vitro approach of human CD8⁺ T cell priming, based on the rapid mobilization of dendritic cells (DCs) directly from unfractionated peripheral blood mononuclear cells (PBMCs). This simple and original method allows for side-by-side comparisons of multiple test parameters in a standardized system, providing both quantitative and qualitative readouts of primed antigen-specific CD8⁺ T cells. Here, we discuss the genesis of this approach and its versatile applications, including monitoring antigen-specific T cell responses, evaluating an individual’s T cell priming capacity, and conducting preclinical studies on potential adjuvants and vaccine candidates. Full article

Background/Objectives: Rapid development of vaccines against SARS-CoV-2 was pivotal to controlling the COVID-19 pandemic. The emergency also provided a rare opportunity to test novel vaccine platforms such as mRNA in large clinical trials. Most of the early vaccines used SARS-CoV-2 Spike protein as the target antigen. Nevertheless, subsequent studies have shown that Receptor Binding Domain (RBD) of Spike also can yield efficacious vaccines, and we previously demonstrated that chemical conjugation of RBD to a carrier protein, EcoCRM^®, enhanced antibody responses and induced strong virus neutralization activity in mice. Methods: Here, we compared the immunogenicity of this conjugate to that of an approved mRNA vaccine from Pfizer/BioNTech in rhesus macaques over a period of nine months. Results: AS01-adjuvanted RBD conjugate induced a similar or better antibody response, receptor binding inhibition, and virus neutralization activity against different variants of SARS-CoV-2, compared to mRNA. IgG subclass profiles induced by conjugate and mRNA vaccines were initially dominated by IgG1 and IgG3 then switched to IgG2 and IgG4 dominant profiles during the subsequent six-month period. Polyclonal immune sera from the conjugate and mRNA had similar antibody avidity at multiple time points. Conclusions: In summary, antibody responses in rhesus macaques induced by the RBD-EcoCRM conjugate and the Spike mRNA vaccine are very similar. These results demonstrate the potential for the RBD-EcoCRM conjugate as a vaccine against SARS-CoV-2. Full article

Breast cancer is a leading cause of cancer-related mortality worldwide, requiring efficient diagnostic tools for early detection and monitoring. Human epidermal growth factor receptor 2 (HER2) is a key biomarker for breast cancer classification, typically assessed using immunohistochemistry (IHC). However, IHC requires invasive biopsies and time-intensive laboratory procedures. In this study, we present a biosensor integrated with a reusable printed circuit board (PCB) and functionalized glucose test strips designed for rapid and non-invasive HER2 detection in saliva. The biosensor achieved a limit of detection of 10⁻¹⁵ g/mL, 4 to 5 orders of magnitude more sensitive than the enzyme-linked immunosorbent assay (ELISA), with a sensitivity of 95/dec and a response time of 1 s. In addition to HER2, the biosensor also detects cancer antigen 15-3 (CA15-3), another clinically relevant breast cancer biomarker. The CA15-3 test demonstrated an equally low limit of detection, 10⁻¹⁵ g/mL, and a higher sensitivity, 190/dec, further validated using human saliva samples. Clinical validation using 29 saliva samples confirmed our biosensor’s ability to distinguish between healthy, in situ breast cancer, and invasive breast cancer patients. The system, which integrates a Bluetooth Low-Energy (BLE) module, enables remote monitoring, reduces hospital visits, and enhances accessibility for point-of-care and mobile screening applications. This ultra-sensitive, rapid, and portable biosensor can serve as a promising alternative for breast cancer detection and monitoring, particularly in rural and underserved communities. Full article

Diagnosis of histoplasmosis is challenging. A rapid, sensitive, and specific method is essential. Serum is a non-invasive and easy sample to obtain in any hospital. The diagnostic accuracy of different techniques that use serum has been evaluated. Forty-one serum samples from patients with proven or probable histoplasmosis were analyzed. Different diagnostic techniques based on the detection of antibodies (ID Fungal Antibody System), antigens (Histoplasma GM EIA and Platelia^TM Aspergillus Ag), and DNA (“in-house” real-time PCR (RT-PCR) were tested and compared. Additionally, the quantification of cytokines and biomarkers related to histoplasmosis was performed. Global results from 27 samples in which all the tests were performed showed that the sensitivity of the Histoplasma GM EIA kit was 87.5% in patients with disseminated infection and HIV as an underlying disease; in immunocompetent (IC) patients, it was 54.5%. The detection of Histoplasma spp. with the ID Fungal Antibody System was positive in 90.9% of IC and in 62.5% of HIV patients. The Platelia-Asp kit had a low performance in both groups of patients (37.5% in HIV and 9% in non-HIV), and, finally, RT-PCR was better in immunosuppressed patients (44% in HIV vs. 27% in non-HIV). The combination of diagnostic techniques increased the detection of Histoplasma infection in inmunosupressed patients. Overall, patient groups infected with H. capsulatum (Hc) showed higher IL-8, IL-6, IL-1β, TNF-α, and IL-18 median values compared to non-Hc-infected controls. The effectiveness of diagnostic techniques on serum samples is highly influenced by the patient’s clinical presentation and underlying condition. Consequently, a thorough assessment of the patient’s clinical presentation and disease phenotype is crucial in selecting the most suitable diagnostic method. Full article

Norovirus, a foodborne pathogen, causes a significant economic and health burden globally. Although detection methods exist, they are expensive and non-field deployable. A flow-based dielectrophoretic biosensor was designed for the detection of foodborne pathogenic viruses and was tested using bacteriophage MS2 as a norovirus surrogate. The flow-based MS2 sensor comprises a concentrator and a detector. The concentrator is an interdigitated electrode array designed to impart dielectrophoretic effects to manipulate viral particles toward the detector in a fluidic channel. The detector is made of a silver electrode conjugated with anti-MS2 IgG to allow for antibody–antigen biorecognition events and is supplied with the electrical current for the purpose of measurement. Serially diluted MS2 suspensions were continuously injected into the fluidic channel at 0.1 mL/min. A cyclic voltammogram indicated that current measurements from single-walled carbon nanotube (SWCNT)-coated electrodes increased compared to uncoated electrodes. Additionally, a drop in the current measurements after antibody immobilization and MS2 capture was observed with the developed electrodes. Antibody immobilization at the biorecognition site provided greater current changes with the antibody-MS2 complexes vs. the assays without antibodies. The electric field applied to the fluidic channel at 10 V_pp and 1 MHz contributed to an increase in current changes in response to MS2 bound on the detector and was dependent on the MS2 concentrations in the sample. The developed biosensor was able to detect MS2 with a sensitivity of 10² PFU/mL within 15 min. Overall, this work demonstrates a proof of concept for a rapid and field-deployable strategy to detect foodborne pathogens. Full article

Respiratory syncytial virus (RSV) continues as the major cause of acute lower respiratory tract infections in children around the world, and its substantial morbidity, particularly among infants and high-risk children, poses a significant burden on healthcare systems worldwide. RSV infections occur as a spectrum, ranging from mild upper respiratory symptoms to severe bronchiolitis and pneumonia, and the number of infections shows seasonal variations in different latitudes, as well as lasting impacts, reflecting the COVID-19 pandemic. The pathogenesis of the virus involves epithelial cell invasion and/or fusion to form syncytia, along with exaggerated immune-mediated responses. Disease severity is known to depend on viral load, strain variation, and host immune immaturity. Severe RSV infection during infancy is notably linked with long-term respiratory sequelae such as recurrent wheezing and asthma. Diagnosis is based on clinical suspicion and laboratory confirmation using rapid antigen testing or nucleic acid amplification tests, namely PCR. Non-pharmaceutical interventions, maternal vaccination, and prophylaxis with monoclonal antibodies, e.g., palivizumab and nirsevimab, a newly introduced long-acting agent, are efficient protective and preventive measures. Treatment is still, for the most part, supportive in nature and focuses on oxygen supplementation, hydration, and respiratory support for patients with more severe disease courses; however, the development of immunoprophylaxis and vaccine candidates shows promise for reducing the global burden of RSV. Full article

Background/Objectives: The COVID-19 pandemic, caused by SARS-CoV-2, required the rapid development of diagnostic tests. SARS-CoV-2, part of the betacoronavirus genus, shares characteristics with SARS-CoV-1, including its ability to survive on surfaces, facilitating the spread of the infection. This study analyzes the technique of nasopharyngeal secretion collection for SARS-CoV-2 diagnosis and compares the accuracy of rapid antigen and molecular tests. Methods: This study had two components: study A assessed the healthcare personnel training in collecting nasopharyngeal secretions and the discomfort associated with applying a questionnaire. Study B compared rapid antigen test accuracy with RT-PCR among children, through a retrospective analysis. The data were statistically analyzed to assess compliance with the testing protocols. Results: In study A, 88 healthcare workers achieved an average compliance score of 7.60 out of 10 regarding the collection procedure. Over 70% of participants correctly followed the fundamental steps of the procedure. Many patients who underwent sample collection reported pain and symptoms such as coughing or sneezing. In study B, 198 pediatric patients were tested using rapid antigen tests, collected simultaneously with RT-PCR. The rapid tests showed a 50% sensitivity and 97.5% specificity. Conclusions: This study indicates that nasopharyngeal specimen collection techniques are based on international recommendations, but improvements could be made to reduce discomfort. Rapid antigen tests are helpful for screening due to their high specificity and negative predictive value. Continuous healthcare personnel training and the monitoring of diagnostic techniques remain essential in managing SARS-CoV-2 and other viral infections. Full article

Background: adenoviruses (AdVs) are DNA viruses that typically cause mild infections in immunocompetent children, and typically involve the respiratory and gastrointestinal tract. Adenoviral pharyngitis is a common paediatric illness, particularly in children under 4 years old. The aim of our 7-year retrospective study, conducted at a tertiary care paediatric emergency department (ED), was to describe the clinical and laboratory characteristics and management of patients with pharyngeal AdV infections. Specifically, we examined how the management of patients with adenoviral pharyngitis has evolved following the introduction of a rapid antigen nasopharyngeal swab test for AdVs, which has been performed directly in the ED since 2023. Methods: in this single-centre retrospective observational study, the demographic and clinical information for children discharged from the ED who had been diagnosed with a pharyngeal AdV infection between 1 January 2017 and 31 December 2023 were retrospectively reviewed. Moreover, we compared data before and after the introduction of rapid AdV antigenic swabs, which have been directly performed in the ED since the beginning of 2023. Statistical analysis was undertaken using the Student’s t-test and Pearson and Fisher’s exact test, as appropriate. Significance was set at p-value < 0.05. Results: during the study period, 172 children were diagnosed with adenoviral pharyngitis based on a positive swab. All patients were febrile, with a median duration of fever of 4 days. Blood tests were requested for 84.9% of patients at admission, resulting in a mean WBC count of 13,250/mmc and a mean CRP of 70.6 mg/L. The highest CRP median values were found on the third day of fever. Out of 383 swabs performed during 2017–2022, 13.6% were positive vs a 32% positive rate for the 372 swabs performed in 2023. The mean duration of observation in the ED before 2023 was 31.4 h vs. 10.4 h in 2023. Similarly, 9% of patients with adenoviral pharyngitis were admitted to a paediatric ward before 2023 and only 0.8% in 2023. Conclusions: the primary reason for ED admission in cases of adenoviral pharyngitis is fever lasting several days due to hyperinflammation. Differential diagnosis with bacterial infection is essential to limit the number of hospitalisations and inappropriate antibiotic therapy. The introduction of the rapid antigen nasopharyngeal swab has simplified the diagnosis of adenoviral pharyngitis, enabling timely and accurate differentiation from bacterial causes. Full article

Background and Objectives: Group A Streptococcus (GAS) is a leading cause of acute pharyngitis with seasonal outbreaks. The coronavirus disease 2019 (COVID-19) pandemic significantly altered respiratory infection trends; however, its impact on GAS pharyngitis (GAS-P) incidence remains unclear. Additionally, data on co-infections with GAS and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are limited. In this study, temporal trends in GAS-P incidence and characteristics of GAS–SARS-CoV-2 co-infections in Japan were examined. Materials and Methods: In this observational study, data from patients who visited the Tokyo Shinagawa Hospital between January 2019 and December 2024 were retrospectively analyzed. Data on GAS and SARS-CoV-2 test results and patient demographics were extracted from medical records. The study period was categorized based on COVID-19-related public health measures as follows: pre-COVID-19 social period (January 2019–April 2020), restricted social period (May 2020–April 2023), and post-restriction period (May 2023–December 2024). GAS incidence stratified by sex, age, and period was calculated. Clinical characteristics of patients co-infected with GAS and SARS-CoV-2 were analyzed. Results: Among 4837 GAS tests, 463 (9.6%) were positive. GAS positivity rates varied significantly: 11.4% (pre-COVID-19), 7.1% (restricted social period), and 12.6% (post-restriction period; p < 0.001). The proportion of pediatric cases decreased significantly during the restricted social period (24.8–5.3%) before rising sharply in the post-restriction period (47.1%, p < 0.001). Among 151 patients tested for GAS and SARS-CoV-2, 14 (9.3%) had co-infections, which were identified exclusively after July 2022. Most patients exhibited mild symptoms, primarily fever and sore throat, with decreased lymphocyte counts despite normal white blood cell counts. Conclusions: In our cohort, the incidence of GAS pharyngitis temporarily declined during COVID-19-related public health measures and subsequently increased, particularly among children, after restrictions were lifted. Limited testing may contribute to the underdiagnosis of GAS–SARS-CoV-2 co-infections. Further large-scale studies are warranted to assess microbial interactions, disease severity, and long-term outcomes. Full article

Background: Seasonal influenza viruses are primarily known for causing respiratory illness, but rare hematologic complications can occur, especially in young children. While influenza A is more commonly linked to severe manifestations, influenza B can similarly precipitate life-threatening cytopenias, particularly in toddlers. Case Presentation: We report the case of a previously healthy 1-year-and-8-months-old girl who presented with a high fever, cough, and marked pallor during peak influenza season. Laboratory tests revealed significant microcytic, hypochromic anemia and severe thrombocytopenia. Rapid antigen testing was positive for influenza B. An extensive workup for other causes of bicytopenia, including leukemia, hemolysis, aplastic anemia, and other viral infections, yielded negative results. The child was managed with urgent red blood cell and platelet transfusions, oseltamivir antiviral therapy, broad-spectrum antibiotics, corticosteroids, and supportive care. Bone marrow aspiration was deferred in light of the rapid hematologic recovery. Her hemoglobin greatly improved, and her platelet count reached normal values at discharge. Conclusions: Our case underscores the need to consider influenza in the differential diagnosis of unexplained cytopenias during flu season. This case illustrates that influenza B can mimic hematologic malignancies. Rapid diagnosis and supportive treatment are essential to avoid fatal outcomes. Influenza vaccination plays a significant role in preventing severe complications, such as those we encountered. Full article

The COVID-19 pandemic has necessitated urgent measures to curb its spread, with vaccination emerging as a pivotal strategy. This prospective observational study evaluated breakthrough COVID-19 infections among healthcare workers (HCWs) vaccinated with Comirnaty (Pfizer-BioNTech) at a tertiary care hospital in Greece. Over an 8-month period, from February to September 2021, 1958 fully vaccinated HCWs were monitored. Rapid antigen tests and RT-PCR tests were conducted weekly for asymptomatic HCWs. Contact tracing and whole-genome sequencing were performed. Results showed that 2.75% (54 cases) of HCWs experienced breakthrough infections. Among these, 25 (45%) were asymptomatic, mild symptoms occurred in 21 (37%), while 7 (13%) had a fever (≥38 °C) alone and 3 (5%) developed high fever (≥39 °C) with respiratory symptoms. Physicians and nursing staff were the most affected groups. Dominant SARS-CoV-2 variants detected included Delta, British, and Wild type variants. Comparison with existing literature underscored the effectiveness of Comirnaty in reducing breakthrough infections. The findings emphasize the importance of continued booster vaccinations and ongoing surveillance to mitigate breakthrough infections among HCWs. Full article