scholarly journals Microbiological Laboratory Diagnosis of Human Brucellosis: An Overview

Pathogens ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1623
Author(s):  
Giovanni Di Bonaventura ◽  
Silvia Angeletti ◽  
Andrea Ianni ◽  
Tommasangelo Petitti ◽  
Giovanni Gherardi
Keyword(s):  
Clinical Symptoms ◽  
Early Stage ◽  
Point Of Care ◽  
Laboratory Diagnosis ◽  
Cross Reactivity ◽  
Diagnostic Methods ◽  
Nucleic Acid Amplification ◽  
Human Brucellosis ◽  
Microbiological Analysis ◽  
Serological Tests

Brucella spp. are Gram-negative, non-motile, non-spore-forming, slow-growing, facultative intracellular bacteria causing brucellosis. Brucellosis is an endemic of specific geographic areas and, although underreported, represents the most common zoonotic infection, with an annual global incidence of 500,000 cases among humans. Humans represent an occasional host where the infection is mainly caused by B. melitensis, which is the most virulent; B. abortus; B. suis; and B. canis. A microbiological analysis is crucial to identifying human cases because clinical symptoms of human brucellosis are variable and aspecific. The laboratory diagnosis is based on three different microbiological approaches: (i) direct diagnosis by culture, (ii) indirect diagnosis by serological tests, and (iii) direct rapid diagnosis by molecular PCR-based methods. Despite the established experience with serological tests and highly sensitive nucleic acid amplification tests (NAATs), a culture is still considered the “gold standard” in the laboratory diagnosis of brucellosis due to its clinical and epidemiological relevance. Moreover, the automated BC systems now available have increased the sensitivity of BCs and shortened the time to detection of Brucella species. The main limitations of serological tests are the lack of common interpretative criteria, the suboptimal specificity due to interspecies cross-reactivity, and the low sensitivity during the early stage of disease. Despite that, serological tests remain the main diagnostic tool, especially in endemic areas because they are inexpensive, user friendly, and have high negative predictive value. Promising serological tests based on new synthetic antigens have been recently developed together with novel point-of-care tests without the need for dedicated equipment and expertise. NAATs are rapid tests that can help diagnose brucellosis in a few hours with high sensitivity and specificity. Nevertheless, the interpretation of NAAT-positive results requires attention because it may not necessarily indicate an active infection but rather a low bacterial inoculum, DNA from dead bacteria, or a patient that has recovered. Refined NAATs should be developed, and their performances should be compared with those of commercial and home-made molecular tests before being commercialized for the diagnosis of brucellosis. Here, we review and report the most common and updated microbiological diagnostic methods currently available for the laboratory diagnosis of brucellosis.

scholarly journals Point-of-Care Diagnostic Tools for Surveillance of SARS-CoV-2 Infections

2021 ◽  
Vol 9 ◽  
Author(s):  
Dhanasekaran Sakthivel ◽  
David Delgado-Diaz ◽  
Laura McArthur ◽  
William Hopper ◽  
Jack S. Richards ◽  
...  
Keyword(s):  
Large Scale ◽  
Clinical Symptoms ◽  
Point Of Care ◽  
Cost Effective ◽  
Nucleic Acid Amplification ◽  
Diagnostic Tools ◽  
Rt Pcr ◽  
Serological Tests ◽  
Polymerase Chain ◽  
Effective Public Health

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a recently emerged and highly contagious virus that causes coronavirus disease 2019 (COVID-19). As of August 24, 2021, there were more than 212 million confirmed COVID-19 cases and nearly 4.4 million deaths reported globally. Early diagnosis and isolation of infected individuals remains one of the most effective public health interventions to control SARS-CoV-2 spread and for effective clinical management of COVID-19 cases. Currently, SARS-CoV-2 infection is diagnosed presumptively based on clinical symptoms and confirmed by detecting the viral RNA in respiratory samples using reverse transcription polymerase chain reaction (RT-PCR). Standard RT-PCR protocols are time consuming, expensive, and technically demanding, which makes them a poor choice for large scale and point-of-care screening in resource-poor settings. Recently developed isothermal nucleic acid amplification tests (iNAAT), antigen and/or serological tests are cost-effective to scale COVID-19 testing at the point-of-care (PoC) and for surveillance activities. This review discusses the development of rapid PoC molecular tools for the detection and surveillance of SARS-CoV-2 infections.

scholarly journals Utility of Available Methods for Diagnosing SARS-CoV-2 in Clinical Samples

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Armin Shirvani ◽  
Leila Azimi ◽  
Roxana Mansour Ghanaie ◽  
Masoud Alebouyeh ◽  
Fatemeh Fallah ◽  
...  
Keyword(s):  
Point Of Care ◽  
Laboratory Diagnosis ◽  
Diagnostic Value ◽  
Clinical Findings ◽  
Diagnostic Methods ◽  
Detection Methods ◽  
Clinical Samples ◽  
Clinical Settings ◽  
Rt Pcr ◽  
Serological Tests

: The laboratory diagnosis of SARS-CoV-2 should be done to confirm coronavirus disease 2019 (COVID-19) in suspected patients. Although several diagnostic methods have been developed in this regard, their accuracy for clinical application is not very clear yet. To compare the diagnostic value of laboratory tests for the detection of COVID-19 infection, this study provides an upcoming review of the newly developed detection methods. Sensitivity, specificity, detection limit, and turn-around-time of these methods are compared and challenges for their application in clinical settings are reviewed. PubMed and Google Scholar web sites were used for the systematic search until April 9, 2020 to identify the published studies based on the following keywords: “Detection”, “Coronavirus 2019”, “SARS-CoV-2”, and “Sensitivity”. Out of 526 results, a total of 54 articles, including 46 studies on detection methods, were considered eligible for the review. The results showed that most of the proposed tests focused on molecular methods, while immunological and point-of-care tests were investigated in 13 studies. There were also a few commercial automated methods for the qualitative detection of SARS-CoV-2 in clinical samples, most of which are not examined in the current review, as no data about their sensitivity and specificity were presented. Although the assessment of publication biases showed that 64% sensitivity and nearly 100% specificity for RT-PCR are close to reality, most of the related reports for serological methods are not valid and further studies are needed to confirm their utility in clinical settings. Moreover, the RT-PCR test alone cannot act as a gold standard because of bias in measurements. Therefore, antibody tests and other proposed methods could be used as supplementary diagnostic tests to improve RT-PCR accuracy. Although clinical findings are invaluable, in many cases, they can provide more valuable supportive data than serological tests.

scholarly journals Clinical-Forensic Autopsy Findings to Defeat COVID-19 Disease: A Literature Review

2020 ◽  
Vol 9 (7) ◽  
pp. 2026 ◽  
Author(s):  
Francesco Sessa ◽  
Giuseppe Bertozzi ◽  
Luigi Cipolloni ◽  
Benedetta Baldari ◽  
Santina Cantatore ◽  
...  
Keyword(s):  
Cause Of Death ◽  
Standard Method ◽  
Point Of Care ◽  
Real Data ◽  
Laboratory Diagnosis ◽  
Diagnostic Techniques ◽  
Diagnostic Methods ◽  
Serological Tests ◽  
Gold Standard Method ◽  
Therapeutic Implications

The severe acute respiratory syndrome (SARS)-CoV-2 was identified for the first time in China, in December 2019. Confirmed cases of COVID-19 have been reported around the world; indeed, this infection has been declared a pandemic. Consequently, the scientific community is working hard to gain useful information about the history of this virus, its transmission, diagnosis, clinical features, radiological findings, research and development of candidate therapeutics as well as vaccines. This review aims to analyze the diagnostic techniques used to ascertain the COVID-19 infection, critically reviewing positive points and criticism for forensic implications, obviously including autopsy. Finally, this review proposes a practical workflow to be applied in the management of corpses during this outbreak of the COVID-19 infection, which could be useful in cases of future infectious disease emergencies. Analyzing the diagnostic methods, to date, virus nucleic acid RT-PCR represents the standard method used to ascertain the COVID-19 infection in living subjects and corpses, even if this technique has several criticisms: mainly, the staff should be highly specialized, working in high-throughput settings, able to handle high workloads and aware of health risks and the importance of the results. Thus, IgG/IgM serological tests have been developed, overcoming RT-qPCR duration, costs, and management, not requiring highly trained personnel. Nevertheless, serological tests present problems; the WHO recommends the use of these new point-of-care immunodiagnostic tests only in research settings. Furthermore, nothing has yet been published regarding the possibility of applying these methods during post-mortem investigations. In light of this scenario, in this review, we suggest a flow chart for the pathologist called on to ascertain the cause of death of a subject with historical and clinical findings of COVID-19 status or without any anamnestic, diagnostic, or exposure information. Indeed, the literature data confirmed the analytical vulnerabilities of the kits used for laboratory diagnosis of COVID-19, particularly during postmortem examinations. For these reasons, autopsy remains the gold standard method to ascertain the exact cause of death (from or with COVID-19 infection, or other causes), to consequently provide real data for statistical evaluations and to take necessary measures to contain the risks of the infection. Moreover, performing autopsies could provide information on the pathogenesis of the COVID-19 infection with obvious therapeutic implications.

scholarly journals Laboratory Diagnosis of Human Brucellosis

2019 ◽  
Vol 33 (1) ◽  
Author(s):  
Pablo Yagupsky ◽  
Pilar Morata ◽  
Juan D. Colmenero
Keyword(s):  
Nucleic Acid ◽  
Laboratory Diagnosis ◽  
Nucleic Acid Amplification ◽  
Human Brucellosis ◽  
Serological Tests ◽  
Therapeutic Implications ◽  
Poor Countries ◽  
And Performance ◽  
Sensitivity Specificity

SUMMARY The clinical presentation of brucellosis in humans is variable and unspecific, and thus, laboratory corroboration of the diagnosis is essential for the patient’s proper treatment. The diagnosis of brucellar infections can be made by culture, serological tests, and nucleic acid amplification assays. Modern automated blood culture systems enable detection of acute cases of brucellosis within the routine 5- to 7-day incubation protocol employed in clinical microbiology laboratories, although a longer incubation and performance of blind subcultures may be needed for protracted cases. Serological tests, though they lack specificity and provide results that may be difficult to interpret in individuals repeatedly exposed to Brucella organisms, nevertheless remain a diagnostic cornerstone in resource-poor countries. Nucleic acid amplification assays combine exquisite sensitivity, specificity, and safety and enable rapid diagnosis of the disease. However, long-term persistence of positive molecular test results in patients that have apparently fully recovered is common and has unclear clinical significance and therapeutic implications. Therefore, as long as there are no sufficiently validated commercial tests or studies that demonstrate an adequate interlaboratory reproducibility of the different homemade PCR assays, cultures and serological methods will remain the primary tools for the diagnosis and posttherapeutic follow-up of human brucellosis.

The laboratory diagnosis of Syphilis

2021 ◽  
Author(s):  
Ferris Satyaputra ◽  
Stephanie Hendry ◽  
Maxwell Braddick ◽  
Pirathaban Sivabalan ◽  
Robert Norton
Keyword(s):  
Congenital Syphilis ◽  
Point Of Care ◽  
Treponema Pallidum ◽  
Laboratory Diagnosis ◽  
Nucleic Acid Amplification ◽  
Current Status ◽  
Serological Tests ◽  
Flocculation Test ◽  
The Many ◽  
Point Of Care Tests

Syphilis is a multisystem infection caused by the spirochaete Treponema pallidum. Currently, cases of possible syphilis are commonly investigated using the treponemal serological tests T. pallidum IgG chemiluminescence immunoassay (CLIA) and the T. pallidum particle agglutination (TPPA). The non-treponemal rapid plasma reagin (RPR) flocculation test is used to assess disease activity. There has been a resurgence of syphilis diagnoses in Australia. Large foci of infection have been identified in isolated communities. The remoteness of these locations, in conjunction with the particular socio-cultural characteristics of the population, pose unique challenges to the traditional diagnostic and treatment paradigms for syphilis. As a consequence of this increased incidence of syphilis, there has been interest in the utility of point of care tests (POCT), nucleic acid amplification tests (NAAT), the role of IgM testing in suspected congenital syphilis, and the laboratory investigation of possible neurosyphilis. This review looks at the current status of traditional serological assays and provides an update on more recent methods. It assesses the published literature in this area and makes recommendations for the rational use of pathology testing to aid in the diagnosis of the many facets of syphilis.

scholarly journals Diagnosis of human brucellosis caused by Brucella canis

2005 ◽  
Vol 54 (5) ◽  
pp. 457-461 ◽  
Author(s):  
Nidia E Lucero ◽  
Gabriela I Escobar ◽  
Sandra M Ayala ◽  
Nestor Jacob
Keyword(s):  
Clinical Symptoms ◽  
Early Stage ◽  
Close Contact ◽  
Cross Reactivity ◽  
Human Brucellosis ◽  
Brucella Canis ◽  
Antigen Tests ◽  
Laboratory Exposure ◽  
Culture Positive ◽  
Positive Results

The transmission of Brucella canis to man commonly occurs through contact with infected dogs or their secretions, or through direct laboratory exposure. The disease is underdiagnosed due to a general lack of serological testing facilities and misconceptions concerning its prevalence. This report shows the potential use of an indirect ELISA (IELISA) for the diagnosis of human brucellosis caused by B. canis in a population of patients negative by smooth-Brucella antigen tests but positive by rapid slide agglutination test (RSAT). One hundred and ten sera from asymptomatic people found negative by tests using smooth Brucella abortus antigen and by RSAT showed an IELISA specificity of 100 % when a cut-off value of 27 % positivity (%P) was selected. For 17 sera from patients with positive B. canis culture or in close contact with culture-positive dogs, the IELISA sensitivity was 100 % with the same cut-off value. The positive patients presented clinical symptoms similar to brucellosis caused by other species of Brucella and some of them received antibiotic treatment and made good progress. Using this cut-off value, we studied 35 patients with negative blood cultures but positive RSATs, and IELISA detected 18 as positive; of the 17 IELISA-negative, two were RSAT-positive at dilution 1 : 2 and 15 were weakly positive with pure serum. These samples were probably from patients at an early stage of infection or indicate false-positive results. No cross-reaction was observed among the sera from nine cases with a diagnosis other than brucellosis, but cross-reactivity was evident in sera from patients infected with smooth-Brucella species. Since routine brucellosis diagnosis does not include B. canis investigation, infection with this species may be more widespread than is currently suspected. The RSAT could be a suitable screening test for the diagnosis of B. canis human brucellosis, and a supplementary technique, such as IELISA, performed on all positive RSAT samples that were negative by B. abortus antigen could ensure diagnostic specificity and confirm the diagnosis.

A point-of-care diagnostic for differentiating Ebola from endemic febrile diseases

2018 ◽  
Vol 10 (471) ◽  
pp. eaat0944 ◽  
Author(s):  
David Sebba ◽  
Alexander G. Lastovich ◽  
Melody Kuroda ◽  
Eric Fallows ◽  
Joshua Johnson ◽  
...  
Keyword(s):  
Ebola Virus ◽  
Clinical Symptoms ◽  
Point Of Care ◽  
Hemorrhagic Fever ◽  
Diagnostic Methods ◽  
Outbreak Detection ◽  
Molecular Diagnostic ◽  
Clinical Samples ◽  
Live Virus ◽  
And Control

Hemorrhagic fever outbreaks such as Ebola are difficult to detect and control because of the lack of low-cost, easily deployable diagnostics and because initial clinical symptoms mimic other endemic diseases such as malaria. Current molecular diagnostic methods such as polymerase chain reaction require trained personnel and laboratory infrastructure, hindering diagnostics at the point of need. Although rapid tests such as lateral flow can be broadly deployed, they are typically not well-suited for differentiating among multiple diseases presenting with similar symptoms. Early detection and control of Ebola outbreaks require simple, easy-to-use assays that can detect and differentiate infection with Ebola virus from other more common febrile diseases. Here, we developed and tested an immunoassay technology that uses surface-enhanced Raman scattering (SERS) tags to simultaneously detect antigens from Ebola, Lassa, and malaria within a single blood sample. Results are provided in <30 min for individual or batched samples. Using 190 clinical samples collected from the 2014 West African Ebola outbreak, along with 163 malaria positives and 233 negative controls, we demonstrated Ebola detection with 90.0% sensitivity and 97.9% specificity and malaria detection with 100.0% sensitivity and 99.6% specificity. These results, along with corresponding live virus and nonhuman primate testing of an Ebola, Lassa, and malaria 3-plex assay, indicate the potential of the SERS technology as an important tool for outbreak detection and clinical triage in low-resource settings.

Clinical and Epidemiological Features of Acute Zika Virus Infections in León, Nicaragua

2021 ◽  
Author(s):  
Natalie M. Bowman ◽  
Filemón Bucardo ◽  
Matthew H. Collins ◽  
Yaoska Reyes ◽  
Edwing Centeno Cuadra ◽  
...  
Keyword(s):  
Risk Factors ◽  
Sore Throat ◽  
Zika Virus ◽  
Clinical Symptoms ◽  
Laboratory Data ◽  
Maculopapular Rash ◽  
Laboratory Diagnosis ◽  
Zikv Infection ◽  
Serological Tests ◽  
Laboratory Findings

The American Zika virus (ZIKV) epidemic has highlighted the need to gain a better understanding of this emerging virus. The goal of this study was to describe the clinical symptoms, laboratory findings, and risk factors for symptomatic ZIKV infection in an area with ongoing transmission of other arboviral infections. We recruited patients at least 2 years of age seeking care at public health centers in León, Nicaragua, between January 2016 and August 2017, for fever, maculopapular rash, and/or nonsuppurative conjunctivitis with a duration of less than 1 week. A laboratory diagnosis of ZIKV was established using a combination of molecular and serological tests. Clinical and laboratory findings and potential risk factors were compared between participants with and without acute ZIKV infection. Fifty-eight (26%) of the 225 participants included in the analysis were found to have acute ZIKV infection. Pregnancy and reports of previous arboviral infection were associated with a higher risk of ZIKV infection. Rash, conjunctivitis, sore throat, and lower absolute neutrophil counts were associated with acute ZIKV infection. The clinical characteristics and risk factors identified were consistent with those identified by previous studies; however, we found sore throat to be a feature of ZIKV infection. We also found that neutrophil counts were lower in ZIKV-infected subjects. These clinical symptoms and laboratory data may help clinicians suspect ZIKV infection during future outbreaks.

scholarly journals Update on Malaria Diagnostics and Test Utilization

2017 ◽  
Vol 55 (7) ◽  
pp. 2009-2017 ◽  
Author(s):  
Blaine A. Mathison ◽  
Bobbi S. Pritt
Keyword(s):  
Gold Standard ◽  
Acute Infection ◽  
Laboratory Diagnosis ◽  
Rapid Diagnosis ◽  
Diagnostic Methods ◽  
Nucleic Acid Amplification ◽  
Advantages And Disadvantages ◽  
Life Threatening ◽  
Antigen Tests ◽  
Malaria Test

ABSTRACT Malaria is a potentially life-threatening disease requiring rapid diagnosis and treatment. Although microscopic examination of thick and thin blood films remains the gold standard for laboratory diagnosis, rapid antigen tests and nucleic acid amplification methods may also play a useful role in detection of acute infection. This review discusses the advantages and disadvantages of the commonly used diagnostic methods and provides important practice points for optimal malaria test utilization.

scholarly journals Smartphone-based Sickle Cell Disease Detection and Monitoring for Point-of-Care Settings

2020 ◽  
Author(s):  
Shazia Ilyas ◽  
Mazhar Sher ◽  
E Du ◽  
Waseem Asghar
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Early Stage ◽  
Point Of Care ◽  
Unmet Need ◽  
Optical Microscope ◽  
Diagnostic Methods ◽  
Sub Saharan Africa ◽  
Cell Disease ◽  
Resource Limited

AbstractSickle cell disease (SCD) is a worldwide hematological disorder causing painful episodes, anemia, organ damage, stroke, and even deaths. It is more common in sub-Saharan Africa and other resource-limited countries. Conventional laboratory-based diagnostic methods for SCD are time-consuming, complex, and cannot be performed at point-of-care (POC) and home settings. Optical microscope-based classification and counting demands a significant amount of time, extensive setup, and cost along with the skilled human labor to distinguish the normal red blood cells (RBCs) from sickled cells. There is an unmet need to develop a POC and home-based test to diagnose and monitor SCD and reduce mortality in resource-limited settings. An early-stage and timely diagnosis of SCD can help in the effective management of the disease. In this article, we utilized a smartphone-based image acquisition method for capturing RBC images from the SCD patients in normoxia and hypoxia conditions. A computer algorithm is developed to differentiate RBCs from the patient’s blood before and after cell sickling. Using the developed smartphone-based technique, we obtained similar percentage of sickle cells in blood samples as analyzed by conventional method (standard microscope). The developed method of testing demonstrates the potential utility of the smartphone-based test for reducing the overall cost of screening and management for SCD, thus increasing the practicality of smartphone-based screening technique for SCD in low-resource settings. Our setup does not require any special storage requirements and is particularly useful in assessing the severity of the SCD. This is the characteristic advantage of our technique as compared to other hemoglobin-based POC diagnostic techniques.

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