Utility of an immunocapture-agglutination test and an enzyme-linked immunosorbent assay test against cytosolic proteins from Brucella melitensis B115 in the diagnosis and follow-up of human acute brucellosis

Undulant Fevers and Bitemporal Headaches: A Clinical Presentation of Human Brucellosis

Brucellosis is a common zoonotic infection endemic to certain areas of the Mediterranean, Middle East, Central America, and Sub-Saharan Africa. We present a case of brucellosis in a patient who recently traveled to Grenada and returned to the United States with a wide degree of symptoms. This case explores the etiology, clinical presentation, investigation, and treatment of brucellosis. Though a patient’s clinical presentation may be non-specific, the recognition of potential etiologies may aid in empirically treating the infection prior to laboratory confirmation.

Biosensors for European Zoonotic Agents: A Current Portuguese Perspective

Emerging and recurrent outbreaks caused by zoonotic agents pose a public health risk. They result in morbidity and mortality in humans and significant losses in the livestock and food industries. This highlights the need for rapid surveillance methods. Despite the high reliability of conventional pathogen detection methods, they have high detection limits and are time-consuming and not suitable for on-site analysis. Furthermore, the unpredictable spread of zoonotic infections due to a complex combination of risk factors urges the development of innovative technologies to overcome current limitations in early warning and detection. Biosensing, in particular, is highlighted here, as it offers rapid and cost-effective devices for use at the site of infection while increasing the sensitivity of detection. Portuguese research in biosensors for zoonotic pathogens is the focus of this review. This branch of research produces exciting and innovative devices for the study of the most widespread pathogenic bacteria. The studies presented here relate to the different classes of pathogens whose characteristics and routes of infection are also described. Many advances have been made in recent years, and Portuguese research teams have increased publications in this field. However, biosensing still needs to be extended to other pathogens, including potentially pandemic viruses. In addition, the use of biosensors as part of routine diagnostics in hospitals for humans, in animal infections for veterinary medicine, and food control has not yet been achieved. Therefore, a convergence of Portuguese efforts with global studies on biosensors to control emerging zoonotic diseases is foreseen for the future.

Status of human brucellosis in district Malakand, Khyber Pakhtunkhwa, Pakistan

BACKGROUND

Brucellosis is a zoonotic disease caused by the bacteria, Brucella genus. Human is always an accidental host, infected from domesticated or wild animals.

METHODS

This study was conducted from September 2017 to April 2018. A total of 304 samples were collected in eight months duration from female of high-risk population connected with domesticated animals to investigate the sero-prevalence of Brucellosis using ELISA (Igm) in District Malakand, Khyber Pakhtunkhwa, Pakistan.

RESULTS

The high age wise prevalence was recorded as 32.25% in female with age group 21-30 by ELISA (P<0.05). The prevalent rate was significantly high (P<0.05) in Tehsil Batkhela (32.8%) than Dargai (22.75%). It was also recorded in the present study that the prevalence was higher from January to April. It was found 20.58%, 17.64%, 14.70%, 20.58%, 17.6%, 38.23%, 45.71% and 44.11% from September to April respectively.

CONCLUSION

The present study concluded that the prevalence of brucellosis is significantly high among the age group 20-40 and from January to April 2018. Further studies will be required to show the prevalence of the Brucellosis all over the country.

Incidence of human brucellosis in the Kilimanjaro Region of Tanzania in the periods 2007-2008 and 2012-2014

Background

Brucellosis causes substantial morbidity among humans and their livestock. There are few robust estimates of the incidence of brucellosis in sub-Saharan Africa. Using cases identified through sentinel hospital surveillance and health care utilization data, we estimated the incidence of brucellosis in Moshi Urban and Moshi Rural Districts, Kilimanjaro Region, Tanzania, for the periods 2007–2008 and 2012–2014.

Methods

Cases were identified among febrile patients at two sentinel hospitals and were defined as having either a 4-fold increase in Brucella microscopic agglutination test titres between acute and convalescent serum or a blood culture positive for Brucella spp. Findings from a health care utilization survey were used to estimate multipliers to account for cases not seen at sentinel hospitals.

Results

Of 585 patients enrolled in the period 2007–2008, 13 (2.2%) had brucellosis. Among 1095 patients enrolled in the period 2012–2014, 32 (2.9%) had brucellosis. We estimated an incidence (range based on sensitivity analysis) of brucellosis of 35 (range 32–93) cases per 100 000 persons annually in the period 2007–2008 and 33 (range 30–89) cases per 100 000 persons annually in the period 2012–2014.

Conclusions

We found a moderate incidence of brucellosis in northern Tanzania, suggesting that the disease is endemic and an important human health problem in this area.

Clinical Interpretation of Detection of IgM Anti-Brucella Antibody in the Absence of IgG and Vice Versa; a Diagnostic Challenge for Clinicians

Non-specific and often misleading clinical presentation of active brucellosis has made it a diagnostic puzzle for treating physicians. Clinicians rely greatly on the detection of IgG and IgM anti-Brucella antibodies by ELISA. Different patterns of positivity have been observed for IgG and IgM anti-Brucella antibodies in different cases, which further increases the risk of an erroneous diagnosis. Detailed herein is our two-years data with varied Brucella serology patterns and their clinical interpretation. Between January 2015 to December 2017, 1102 samples were processed in the Immunology Laboratory of KFHU for Brucella serology. 68 samples were positive for both IgG and IgM, 28 samples were positive for IgG and negative for IgM while 15 samples were positive for IgM and negative for IgG antibodies against Brucella. Electronic medical records, history of exposure, signs, symptoms, laboratory data, and the final diagnosis were recorded for all these patients. None of the patients with only positive IgM antibodies was finally diagnosed with brucellosis, while a diagnosis of brucellosis was established for only one patient with IgG antibodies positive in his serum. All the double-positive (IgG- and IgM-positive) serology patterns were diagnosed as having brucellosis. We concluded that determination of single IgM or IgG anti-Brucella-antibodies by ELISA could both be considered as definite and should ideally be interpreted in the context of appropriate clinical scenario and confirmation by other laboratory assays.

Non-specific and often misleading clinical presentation of active brucellosis has made it a diagnostic puzzle for treating physicians. Clinicians rely greatly on the detection of IgG and IgM anti-Brucella antibodies by ELISA. Different patterns of positivity have been observed for IgG and IgM anti-Brucella antibodies in different cases, which further increases the risk of an erroneous diagnosis. Detailed herein is our two-years data with varied Brucella serology patterns and their clinical interpretation. Between January 2015 to December 2017, 1102 samples were processed in the Immunology Laboratory of KFHU for Brucella serology. 68 samples were positive for both IgG and IgM, 28 samples were positive for IgG and negative for IgM while 15 samples were positive for IgM and negative for IgG antibodies against Brucella. Electronic medical records, history of exposure, signs, symptoms, laboratory data, and the final diagnosis were recorded for all these patients. None of the patients with only positive IgM antibodies was finally diagnosed with brucellosis, while a diagnosis of brucellosis was established for only one patient with IgG antibodies positive in his serum. All the double-positive (IgG- and IgM-positive) serology patterns were diagnosed as having brucellosis. We concluded that determination of single IgM or IgG anti-Brucella-antibodies by ELISA could both be considered as definite and should ideally be interpreted in the context of appropriate clinical scenario and confirmation by other laboratory assays.

Neurobrucellosis in systemic lupus erythematosus

Background:

Brucellosis is a zoonotic infection which is endemic in many countries. It is a multisystem disease which may present with a broad spectrum of clinical manifestations and complications. Neurobrucellosis is an uncommon complication of brucellosis.

Case presentation:

A 25-year-old woman with a history of lupus for 5 months referred to the emergency ward of Shahid Beheshti Hospital of Qom due to vertigo, drop attack and a convulsion episode from the previous day. She was unable to move at initial evaluation, and her upper and lower extremities were spastic. She had blurred vision one day after admission. Based on her past history and suspecting neurological pulmonary presentations, treatment with immunosuppressive drugs was started and brain MRI was performed. According to the MRI mode and endemic area, neurobrucellosis was suspected and 2ME and Wright tests were performed. Wight test was 1.5120 while 2ME test was 1.640 which were strongly positive. So, with neurobrucellosis diagnosis, the patient was treated but unfortunately 4 days later, after respiratory apnea, she was pronounced dead.

Conclusion:

In endemic areas for brucellosis, neurobrucellosis should always be kept in mind in the differential diagnosis of neurological and psychiatric cases that are encountered.

Epidemiological, diagnostic, clinical, and therapeutic aspects of Brucella bacteremia in children in southern Israel: a 7-year retrospective study (2005-2011)

BACKGROUND

Data on the various aspects of brucellosis in children living in southern Israel are missing.

OBJECTIVES

Our aim was to study the epidemiological, microbiological, diagnostic, clinical, therapeutic and outcome features of brucellosis in children <19 years of age in southern Israel during 2005-2011.

PATIENTS AND METHODS

The study population included all patients hospitalized with a diagnosis of brucellosis, established according to a clinical presentation compatible with brucellosis+presence of Brucella bacteremia (BB).

RESULTS

A total of 128 (50.8%) of 252 patients admitted with a diagnosis of brucellosis had BB (all with Brucella melitensis). All patients were of Muslim Bedouin ethnicity. The mean incidence of BB in southern Israel was 16 cases/100,000 Bedouin, with no significant changes during the study period. Overall duration of symptoms before diagnosis was 10.1±10.9 days. Fever at diagnosis was recorded in <20% of the patients. The most frequent symptoms were arthralgia (61.7%), weakness (32.8%), gastrointestinal disturbances (27.3%), myalgia (25%), and headache (18.8%). The main clinical findings included monoarthritis (36.7%), hepatosplenomegaly (25%), lymphadenopathy (17.2%), heart murmur (11.7%), and skin rash (9.4%), respectively. Anemia, leukopenia, thrombocytopenia, and pancytopenia were reported in 17.6%, 29.6%, 12.8%, and 2.3% of the patients, respectively. Twenty-nine (30.5%) patients with BB had serum agglutinin titers ≤1/160 (13, 13.7%%, had titers <1/160). Twenty-seven (93%) of the 29 patients aged 0-4 years were treated with gentamicin and trimethoprim-sulfamethoxazole; a total of 77 (60.2%) patients received gentamicin and doxycycline.

CONCLUSIONS

Childhood brucellosis remains an important public health problem in southern Israel. BB was diagnosed in >50% of the children with brucellosis, and B. melitensis was identified in all cases. Arthralgia, weakness, and gastrointestinal complaints were the most common symptoms, and monoarthritis, hepatosplenomegaly, and lymphadenopathy were the most common clinical findings. A considerable number of patients with BB had undetectable/low serum agglutinin titers, suggesting insufficient reliability on serology alone in diagnosis of brucellosis.

A protein-conjugate approach to develop a monoclonal antibody-based antigen detection test for the diagnosis of human brucellosis

Human brucellosis is most commonly diagnosed by serology based on agglutination of fixed Brucella abortus as antigen. Nucleic acid amplification techniques have not proven capable of reproducibly and sensitively demonstrating the presence of Brucella DNA in clinical specimens. We sought to optimize a monoclonal antibody-based assay to detect Brucella melitensis lipopolysaccharide in blood by conjugating B. melitensis LPS to keyhole limpet hemocyanin, an immunogenic protein carrier to maximize IgG affinity of monoclonal antibodies. A panel of specific of monoclonal antibodies was obtained that recognized both B. melitensis and B. abortus lipopolysaccharide epitopes. An antigen capture assay was developed that detected B. melitensis in the blood of experimentally infected mice and, in a pilot study, in naturally infected Peruvian subjects. As a proof of principle, a majority (7/10) of the patients with positive blood cultures had B. melitensis lipopolysaccharide detected in the initial blood specimen obtained. One of 10 patients with relapsed brucellosis and negative blood culture had a positive serum antigen test. No seronegative/blood culture negative patients had a positive serum antigen test. Analysis of the pair of monoclonal antibodies (2D1, 2E8) used in the capture ELISA for potential cross-reactivity in the detection of lipopolysaccharides of E. coli O157:H7 and Yersinia enterocolitica O9 showed specificity for Brucella lipopolysaccharide. This new approach to develop antigen-detection monoclonal antibodies against a T cell-independent polysaccharide antigen based on immunogenic protein conjugation may lead to the production of improved rapid point-of-care-deployable assays for the diagnosis of brucellosis and other infectious diseases.

Magnetic resonance imaging findings of musculoskeletal brucellosis

OBJECTIVE

The aim of this retrospective study was to determine the magnetic resonance imaging (MRI) findings of patients with musculoskeletal brucellosis.

MATERIALS AND METHODS

Sixty-eight among 304 patients with musculoskeletal brucellosis, aged 12-82 years (average, 50.2 years), were included in the study. Patients were diagnosed based on clinical findings, Brucella agglutination tests, and MRI findings. MRI was performed to all of the patients with sacroiliitis, spondylitis-spondylodiscitis, and peripheral arthritis.

RESULTS

Brucella serum agglutination test was >1/160 in all cases and blood cultures were positive in twelve cases. The most commonly affected site was the spine (57.3%), wherein lumbar vertebrae were found to be most commonly affected. The second most common affected site was sacroiliac joint (26.4%), whereas peripheral joints were affected in 11 cases (16.1%).

CONCLUSION

Brucellosis may affect various sites in musculoskeletal system. The spine was the most frequently affected site in our study. Sacroiliac joints and the other peripheral joints were less commonly involved sites. Brucellosis should be included in the differential diagnosis of a patient with arthralgia or symptoms of musculoskeletal system disorders especially in endemic areas.

Comparison of total antibody and interferon-γ T-cell responses in patients following infection with brucellosis in Georgia

Brucellosis is an ancient disease that still remains a significant threat to humans and is typically linked to exposure to infected animals and/or consumption of unpasteurized animal products. Despite this history, we have a relatively limited understanding of the host characteristics of this disease; consequently, further research is necessary. In this study, we examined the humoral immune response in 43 Georgian individuals that had been diagnosed with brucellosis 3-12 months before enrollment in the study, many of whom still had symptoms after the completion of antibiotic therapy. In total, 35 of 43 (83%) of the patients had antibodies that bound to Brucella lipopolysaccharide (LPS) by COMPELISA, and 34 of 38 (89%) patients had demonstrable specific antibodies to Brucellergene™ antigens; the results from the two ELISAs were highly correlated (p=0.031, r=0.851). We also studied the cellular immune responses in 15 patients. All of the patients generated interferon (IFN)-γ in response to ex vivo stimulation with Brucella protein antigens, and the majority of the patients maintained measurable humoral responses to both LPS and protein antigens. From this initial study, we conclude that measurement of antibody and of cellular (IFN-γ) responses to brucellergene OCB protein epitopes may be worthy of further investigation as an alternative or adjunct to current diagnostics.

Limitations of the standard agglutination test for detecting patients with Brucella melitensis bacteremia

The sensitivity of the standard agglutination test (SAT) for detecting brucellosis was determined in 264 Israeli patients from whom a positive blood culture for Brucella melitensis and serology were obtained within ± 1 week. A SAT titer ≥1:160 had a diagnostic sensitivity of 91.7%, whereas raising the cutoff to ≥1:320, as recommended to decrease false-positive rates in endemic areas, reduced the sensitivity to 82.6%. Physicians working in regions endemic for brucellosis should be aware of the limitations of the SAT for detecting patients with the disease.

Comparison of four commercial IgM and IgG ELISA kits for diagnosing brucellosis

Brucellosis is a worldwide zoonotic disease that often requires serology for diagnosis. The serum agglutination test is the gold standard assay, but ELISAs are used by many laboratories. Many commercial ELISAs are available, but few studies have compared their performance. This study compared the ability of four commercially available ELISA kits (from Bio-Quant, Immuno-Biological Laboratories - America, Vircell and Euroimmun) to diagnose brucellosis in patients from Egypt and the USA. The sensitivities for all kits tested, except the Vircell kit, were >90%, whilst the specificities were variable, with the Bio-Quant assay having a specificity of <40%. Detection of IgG antibody was more sensitive than detection of IgM antibody for diagnosing brucellosis cases, but the specificity was comparable. Overall, there was good agreement between all of the kits except for the Bio-Quant kit. None of the diagnostic assays was 100% reliable for diagnosing brucellosis; therefore, serology results need to be considered in tandem with patient history, clinical signs and other test results.

Large scale immune profiling of infected humans and goats reveals differential recognition of Brucella melitensis antigens

Brucellosis is a widespread zoonotic disease that is also a potential agent of bioterrorism. Current serological assays to diagnose human brucellosis in clinical settings are based on detection of agglutinating anti-LPS antibodies. To better understand the universe of antibody responses that develop after B. melitensis infection, a protein microarray was fabricated containing 1,406 predicted B. melitensis proteins. The array was probed with sera from experimentally infected goats and naturally infected humans from an endemic region in Peru. The assay identified 18 antigens differentially recognized by infected and non-infected goats, and 13 serodiagnostic antigens that differentiate human patients proven to have acute brucellosis from syndromically similar patients. There were 31 cross-reactive antigens in healthy goats and 20 cross-reactive antigens in healthy humans. Only two of the serodiagnostic antigens and eight of the cross-reactive antigens overlap between humans and goats. Based on these results, a nitrocellulose line blot containing the human serodiagnostic antigens was fabricated and applied in a simple assay that validated the accuracy of the protein microarray results in the diagnosis of humans. These data demonstrate that an experimentally infected natural reservoir host produces a fundamentally different immune response than a naturally infected accidental human host.

Brucellosis is a bacterial disease transmitted from infected animals to humans. This disease often presents as a prolonged but non-specific illness primarily characterized as fever without specific organ localization. Because infections can result after ingestion (typically from unpasteurized animal milk or milk products from goats, cattle or sheep) or inhalation (important because of bioterrorism potential) of small numbers of organisms, the bacteria that cause brucellosis are potential biological warfare agents. Here, a protein microarray containing 1406 Brucella melitensis proteins was used to study the antibody response of experimentally infected goats and naturally infected humans in B. melitensis infection. Goats recognized 18 proteins and humans recognized 13 proteins as serodiagnostic antigens; antibody detection of only two of these antigens was shared by goats and humans, suggesting either fundamentally different immune responses or different responses in relation to mode or setting of infection. The human serodiagnostic antigens were evaluated in a simple nitrocellulose line blot assay, which validated the protein microarray results. The approach described here will lead to the development of new diagnostics for brucellosis and other infectious diseases, and aid in understanding the human and animal host immune response to pathogenic organisms.

Multiple abscesses in brucellosis with Wright's test negativity

We report a case of metastatic abscesses caused by a chronic form of brucellosis in a shepherd. When she was admitted the patient was cachectic with haematological signs of phlogosis. An abdominal computed tomography scan revealed the presence of multiple hepatic and renal abscesses with a fluid mass in the abdominal wall. The blood cultures, tuberculin skin test, and Wright reaction all gave negative results, but the brucellosis Coombs test for Brucella species was highly positive. Diagnosis was confirmed by a high titre of anti-Brucella IgM antibodies. The patient started antibiotic treatment with a progressive clinical improvement, but after discharge she was lost to follow-up and died 7 months later.

Influence of brucellosis history on serological diagnosis and evolution of patients with acute brucellosis

Serological diagnosis of human brucellosis is problematic in endemic brucellosis regions and with patients having a history of brucellosis. The aim of this study is to ascertain the serologic and evolutionary behavior of the tests of serum agglutination, Coombs anti-Brucella, immunocapture-agglutination, enzyme-linked immunosorbent assay (ELISA) IgG, IgA, IgM and ELISA-IgG avidity against Brucella lipopolysaccharide (S-LPS), in patients with acute brucellosis based on whether or not a history of brucellosis exists. Titers and seropositivity in all the tests assayed were higher in the patients having brucellosis history (from 90.9% in ELISA-IgM to 100% in ELISA-IgG) than in the patients lacking such history (from 79.3% in ELISA-IgM to 86.2% in Coombs, immunocapture-agglutination, and ELISA-IgG). IgG S-LPS avidity results in patients with brucellosis history were significantly higher (always over 84%) than in patients without brucellosis history (from 48.0% in the initial sera to 81% ten months later) (p<0.001). The titers of antibodies against Brucella in the initial sera and ELISA-IgG avidity against S-LPS may allow distinguishing patients with brucellosis caused by primary infection in the initial stages of the disease from patients seropositive due to prior infections from Brucella.

Human brucellosis

Human brucellosis still presents scientists and clinicians with several challenges, such as the understanding of pathogenic mechanisms of Brucella spp, the identification of markers for disease severity, progression, and treatment response, and the development of improved treatment regimens. Molecular studies have shed new light on the pathogenesis of Brucella spp, and new technologies have permitted the development of diagnostic tools that will be useful in developing countries, where brucellosis is still a very common but often neglected disease. However, further studies are needed to establish optimum treatment regimens and local and international control programmes. This Review summarises current knowledge of the pathogenic mechanisms, new diagnostic advances, therapeutic options, and the situation of developing countries in regard to human brucellosis.

Relevance of autoantibody detection to the rapid diagnosis of brucellosis

The rose bengal test is often used for rapid diagnosis of human brucellosis in endemic areas. However, autoantibodies have never been investigated as a reason for false-positive or false-negative results. Therefore, the aim of this study was to show the effect of autoantibody detection on the rapid diagnosis of human brucellosis in an endemic area. The study included 2 groups: antinuclear antibody (ANA)-positive and ANA-negative groups. Diagnosis of brucellosis was established by isolation of Brucella spp. from blood culture. The overall sensitivity and specificity of the rose bengal test were 100% and 90.8%, respectively. The specificity (100% versus 89%) and positive predictive value of the test (100% versus 8%) fell markedly from the ANA-negative to the ANA-positive group. As a conclusion, this study verified our suspicion about the effect of autoantibodies on rose bengal test results to the diagnosis of human brucellosis. However, to have definite decisions, extensive studies with larger populations are needed.