Laboratory Diagnosis Of Brucellosis Research Articles

The Development of Diagnostic and Vaccine Strategies for Early Detection and Control of Human Brucellosis, Particularly in Endemic Areas

Brucellosis is considered one of the most serious zoonotic diseases worldwide. This disease affects both human and animal health, in addition to being one of the most widespread zoonotic illnesses in the Middle East and Northern Africa. Human brucellosis generally presents in a diverse and non-specific manner, making laboratory confirmation of the diagnosis critical to the patient's recovery. A coordinated strategy for diagnosing and controlling brucellosis throughout the Middle East is required, as this disease cannot be known to occur without reliable microbiological, molecular, and epidemiological evidence. Consequently, the current review focuses on the current and emerging microbiological diagnostic tools for the early detection and control of human brucellosis. Laboratory assays such as culturing, serology, and molecular analysis can frequently be used to diagnose brucellosis. Although serological markers and nucleic acid amplification techniques are extremely sensitive, and extensive experience has been gained with these techniques in the laboratory diagnosis of brucellosis, a culture is still considered to be the "gold standard" due to the importance of this aspect of public health and clinical care. In endemic regions, however, serological tests remain the primary method of diagnosis due to their low cost, user-friendliness, and strong ability to provide a negative prediction, so they are commonly used. A nucleic acid amplification assay, which is highly sensitive, specific, and safe, is capable of enabling rapid disease diagnosis. Patients who have reportedly fully healed may continue to have positive molecular test results for a long time. Therefore, cultures and serological methods will continue to be the main tools for diagnosing and following up on human brucellosis for as long as no commercial tests or studies demonstrate adequate interlaboratory reproducibility. As there is no approved vaccine that prevents human brucellosis, vaccination-based control of animal brucellosis has become an important part of the management of human brucellosis. Over the past few decades, several studies have been conducted to develop Brucella vaccines, but the problem of controlling brucellosis in both humans and animals remains challenging. Therefore, this review also aims to present an updated overview of the different types of brucellosis vaccines that are currently available.

Particular qualities of laboratory approaches in complex diagnosis of human brucellosis

Brucellosis is an infectious particularly dangerous zoonotic disease caused by bacteria of the genus Brucella, among which B. melitensis, B. abortus, and B. suis have pathogenic potential, causing a severe and often chronic course of the disease.
 Laboratory diagnostics is crucial for the detection of human cases, since the clinical symptoms of human brucellosis are variable and nonspecific. Laboratory diagnosis of brucellosis is based on three different approaches: direct bacteriological method, indirect method using serological and allergic tests and direct express method in different formats of molecular polymerase chain reaction.
 Despite the accumulated experience of using serological tests and the highly sensitive polymerase chain reaction method, the isolation of Brucella culture is considered the gold standard in the laboratory diagnosis of brucellosis due to its clinical and epidemiological relevance. The currently available automated systems of the bacteriological method have increased its sensitivity and shortened the detection time of Brucella species.
 The main limitations of serological tests are the lack of general interpretation criteria, low specificity due to cross-reactions with other bacteria and low sensitivity at an early stage of the disease. At the same time, in Russia, serological tests account for more than 99% of all laboratory tests and remain the main diagnostic tool. This is due to their inexpensive and convenient use at the place of medical care in endemic areas and high negative prognostic value.
 Polymerase chain reaction in various formats of rapid tests diagnoses the DNA of the pathogen in a few hours with high sensitivity and specificity. Nevertheless, a positive polymerase chain reaction result requires careful interpretation and does not necessarily indicate an active infection.
 For the convenience of using diagnostic approaches to brucellosis in practical medicine and determining the activity of the infectious process, it is necessary to improve diagnostics and develop express methods.
 The review shows both the most routine and modern laboratory methods currently available for laboratory diagnosis of brucellosis.

Qualitative Indicators of Experimental Brucellosis Antigen Preparations Designed for Cellular Tests in vitro

In order to develop the most diagnostically informative methods for carrying out antigen-stimulated cellular tests in vitro a careful selection of stimulating agent (antigen) is required, possessing an adequate activating potential and providing specificity of the reaction.Objective of the study was to identify the qualitative indicators of experimental batches of brucellosis antigen preparations designed for cellular tests in vitro.Materials and methods. Initially we produced antigen complexes of brucellosis microbe on the basis of the vaccine strains of three epidemically significant Brucella species (B. abortus, B. melitensis, B. suis). Quantitative determination of WsAg and PPBC proteins of experimental preparation series was performed applying capillary electrophoresis. Qualitative composition was assessed through ion exchange liquid chromatography with refractometric detection.Results and discussion. We have specified physical-chemical features, investigated chromatographic profiles and composition of protein fractions, as well as tried the produced experimental batches of brucellosis antigen preparations. After analyzing the defined protein and polysaccharide composition of the obtained WsAg samples, one can conclude that WsAg preparation cannot be used for cellular tests as the probability of non-specific lymphocyte reaction manifestation in vitro was experimentally proven. By contrast, complex brucellosis antigen preparation PPBC has an expressed specific activity and specificity under in vitro conditions and the prospects to be used when developing methodological approaches for laboratory diagnosis of brucellosis and assessment of de facto immunity rate in risk contingents after vaccination. The obtained parameters will allow for proper quality provision when manufacturing the developed experimental PPBC preparation designed for cellular tests in vitro, taking into account modern validation and standardization regulations.

Low incidence and the prevalence of brucellosis among patients with pyrexia of unknown origin based on real-time polymerase chain reaction, enzyme-linked immunosorbent assay and standard agglutination test results in Puducherry, South India

CONTEXT: Brucellosis is a zoonotic disease and an important differential to be considered in patients with pyrexia of unknown origin (PUO). The laboratory diagnosis of brucellosis has always been affected by various factors such as the slow growth of the organism and cross-reacting antibodies. Hence, a diagnostic test with high sensitivity and specificity is the key for the accurate and rapid diagnosis. AIM: The study aimed to evaluate the role of real-time polymerase chain reaction (PCR) in the rapid diagnosis of human brucellosis from direct serum samples of patients with PUO. MATERIALS AND METHODS: An observational study was conducted from October 2014 to September 2016 at a tertiary care hospital in Puducherry where 138 blood samples were obtained from the patients with PUO. Serum separated from each sample was tested for brucellosis using Cobas 480 Z real-time PCR system. Simultaneously, the samples were also subject to blood culture, standard agglutination test (SAT) and enzyme-linked immunosorbent assay (ELISA) (IgG and IgM) for brucellosis. RESULTS: All the samples were found to be negative for brucellosis using real-time PCR. Blood culture also did not yield any growth of Brucella spp. Among the serological tests, all the samples were negative by SAT, whereas two were positive for IgM and four for IgG anti-Brucella antibodies using ELISA. CONCLUSION: Brucellosis is not a common cause of PUO among patients attending this hospital since all the samples were negative by highly sensitive and specific tests such as real-time PCR and blood culture. This study highlights the limitations of serological tests such as ELISA in the accurate diagnosis of brucellosis.

Updates in Diagnostic Techniques for Brucellosis in Livestock

Brucellosis is a zoonotic disease affecting human as well as domestic animals with worldwide distribution. There are several direct and indirect methods are available for diagnosis of brucellosis in animals. Traditionally, isolation of bacteria by culturing on selective media followed by bacteriological characterisation was done for diagnosis, but it is time consuming. Serological tests are having its own importance for laboratory diagnosis of brucellosis as most of the papers published till date use these methods for screening samples. With advancement in molecular biology and biotechnology, different techniques like polymerase chain reaction (PCR), real-time PCR, loop-mediated isothermal amplification assay are gaining importance for diagnosis of brucellosis in livestock now a day's. These methods are more sensitive and give more accurate results than traditional methods.

Lab diagnosis of brucellosis

Abstract Brucellosis is a widespread zoonotic disease posing serious public health problem especially in developing countries. The diagnosis of brucellosis is a greater challenge, as it requires a high index of suspicion, clinical and laboratory evidence of diagnosis. Increased travel across the globe to endemic areas for work and pleasure over the last few years has led to increased diagnostic challenges in non-endemic countries. Laboratory diagnosis of brucellosis is essential for diagnosis and effective treatment, as it involves two drugs or more for a prolonged period unlike many other infections. Among the various tests available, culture of the organism from the bone marrow, blood and other tissues is the gold standard for diagnosis in brucellosis. However, it is invasive, time consuming and at times less sensitive. These drawbacks have prompted the use of alternate methods to rapidly and accurately diagnose brucellosis and aid in early intervention or therapy. The alternate methods predominantly include serological tests such as enzyme-linked immunosorbent assay, serum agglutination testing and molecular tests with varying advantages and drawbacks suited to various clinical situations. These tests help not only in diagnosis but also in follow-up of disease activity/response to therapy. This article reviews the various culture methods, serological tests and newer diagnostic methods available in making a laboratory diagnosis of brucellosis along with their advantages and drawbacks.

Comparative evaluation of various serological tests in the laboratory diagnosis of Brucellosis

Introduction: Brucellosis is a zoonotic disease of public health importance having an impact on animal husbandry and dairy industry. Isolation of bacteria from blood cultures is very low, and diagnosis mainly depends on serology and molecular methods. The aim of this study is to know the impact of various serological tests on the diagnosis of brucellosis. Materials and Methods: In a prospective study, a total of 180 samples, 90 from pyrexia of unknown origin (PUO) and 90 from high-risk group comprising veterinarians and animal handlers were serologically tested by Rose Bengal plate test, standard tube agglutination (STA) test and enzyme-linked immunosorbent assay (ELISA) and results were analyzed. Results: Out of 90 PUO cases, 28 were positive for brucellosis and in high-risk group, out of 30 veterinarians three were positive and out of 60 animal handlers 14 were positive. Male preponderance was seen. Rose Bengal and STA tests were still efficient methods for brucellosis serodiagnosis. The ELISA was observed to be more efficient in both acute and chronic brucellosis. Conclusion: All the three methods used are efficient methods for detecting Brucella antibody. Rose Bengal card test is the best suited for rapid diagnosis in rural endemic area as STA test is laborious and time-consuming. ELISA is the most sensitive test.

Comparison of Three Blood Culture Techniques in the Diagnosis of Human Brucellosis

Background:Isolation of Brucella is the gold standard in the laboratory diagnosis of brucellosis. As Brucella is intracellular and the number of circulating bacteria is usually low, removal/dilution of antibacterial substances, concentration of bacteria and optimal culture conditions may enhance the rate of isolation.Aims and Objectives:The objective of the following study was to compare the lysis concentration (LC), clot culture and conventional Castaneda blood culture techniques for the isolation rate and recovery time in the diagnosis of human brucellosis.Materials and Methods:Blood cultures by LC, clot culture and conventional method were performed in 169 patients who had antibody titers ≥160 international units by the serum agglutination test.Results:Overall blood culture positivity was found to be 24.8%, 43.1% and 34.9% by conventional, LC and clot culture techniques in that order. The mean recovery time by LC and clot culture techniques was significantly less than conventional method, resulting in an overall difference of nearly 6 and 4 days respectively.Conclusions:For the isolation of Brucella from blood, LC and clot culture techniques are better than the conventional technique.

Laboratory Diagnosis of Brucellosis Using the Slide and Standard Tube Agglutination Methods

Both the rapid slide and standard tube agglutination methods were used for the diagnosis of 112 blood specimens for Brucellosis. We found that 56% of the patients have a titer < 1:20 while 33% have a titer > 1:80. We found that the rapid slide agglutination method correlates well with the tube agglutination method.