Rapid diagnosis of central nervous system brucellosis by ELISA

Laboratory Diagnosis of Human Brucellosis

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.

Outbreak of human brucellosis in Southern Brazil and historical review of data from 2009 to 2018

Background

Human brucellosis (HB) is a bacterial zoonosis that is more frequent in low income and middle-income countries; it is sometimes associated with outbreaks. The aim of this study was to describe the largest outbreak of HB in Brazil.

Methods

A retrospective cohort study of patients suspected of having contracted HB in the state of Paraná, Southern Brazil from January 2009 to January 2017. Following an outbreak of 51 cases of HB in a slaughterhouse at Paiçandu in 2014, HB was defined as an obligatory reportable disease in the State. Diagnostic tests for HB included serum agglutination, ELISA (IgG or IgM) and polymerase chain reaction (PCR). Clinical, laboratorial and epidemiological data were analyzed. A P value of 0.05 was considered statistically significant.

Results

Out of a total of 3,941 patients, 754 presented with a positive test result for HB. After 2014, there was a significant increase in the number of cases, exceeding 100 cases per trimester. In the beginning of 2015, the workgroup of HB started several actions for prevention and treatment, and the number of cases progressively diminished to fewer than 20 cases per trimester. Of 191 reported cases, an occupational risk was found in 84.7%; most cases occurred in farmers (60.0%), veterinarians (17.6%) and slaughterhouse workers (14.7%). Manipulation of animals and unpasteurized milk consumption were associated with positive Brucella IgM ELISA with an odds ratio (OR) of 1.42 (1.09–1.84) and 1.48 (1.01–2.15), respectively.

Conclusions

HB outbreaks can occur in low to middle-income countries and are associated with slaughterhouse work, handling of unpasteurized milk and animal manipulation. Intensive programs for control of HB are important to reduce the number of cases.

Human brucellosis (HB) is a bacterial zoonosis more frequent in low income and middle-income countries. The number of cases has increased in Southern Brazil since 2014. Considering the risk of dissemination of the disease, the authors evaluated the whole spectrum of the disease in the State of Paraná, where cases were reported. More than 3,500 patients at risk for the disease were evaluated and 754 presented with positive blood test results for human brucellosis. The local Health Agency established a program of brucellosis treatment and prevention in the following year. After the intensive control program, there was a significant reduction in the number of HB cases.

Neurobrucellosis: clinical and diagnostic features

BACKGROUND

We describe the neurological involvement in brucellosis and revisited diagnostic criteria for neurobrucellosis.

METHODS

Patients with laboratory-confirmed brucellosis who were consequently hospitalized were observed prospectively in a brucellosis-endemic region. The neurobrucellosis was diagnosed by any one of the following criteria: (1) symptoms and signs consistent with neurobrucellosis; (2) isolation of Brucella species from cerebrospinal fluid (CSF) and/or presence of anti-Brucella antibodies in CSF; (3) the presence of lymphocytosis, increased protein, and decreased glucose levels in CSF; or (4) diagnostic findings in cranial magnetic resonance imaging or CT.

RESULTS

Lumbar puncture was performed in 128 laboratory-confirmed brucellosis cases who had neurological symptoms and signs, and 48 (37.5%) were diagnosed as neurobrucellosis. The sensitivity of tube agglutination (TA) in CSF was 0.94, specificity 0.96, positive predictive value 0.94, and negative predictive value 0.96. Brucella bacteria were isolated from CSF in 7 of 48 patients (15%). The mean age of 48 neurobrucellosis patients was 42 years (SD, 19 years), and 16 (33%) were female. The most common neurological findings were agitation (25%), behavioral disorders (25%), muscle weakness (23%), disorientation (21%), and neck rigidity (17%). Cranial nerves were involved in 9 of 48 patients (19%). One patient was left with a sequela of peripheral facial paralysis and 2 patients with sensorineural hearing loss.

CONCLUSIONS

Patients with severe and persistent headache and other neurologic symptoms and signs should be considered for neurobrucellosis in endemic regions and to possibly receive longer therapy than 6 weeks. Brucella TA with Coombs test in CSF is sensitive and specific by using a cutoff of ≥1:8.

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.

Irreversible papillitis and ophthalmoparesis as a presenting manifestation of neurobrucellosis

A 35-year-old man presented with a meningeal syndrome and acute onset of visual blurring. Clinical investigations revealed bacterial meningitis with bilateral papillitis and ophthalmoparesis. Serum and cerebrospinal fluid serology confirmed the diagnosis of chronic active neurobrucellosis. Following therapy there was no improvement and he developed optic atrophy. Extensive literature review revealed, one case of bilateral irreversible papillitis resulting from neurobrucellosis. However no cases of neurobrucellosis have been reported with meningitis, irreversible papillitis and ophthalmoparesis. This case demonstrates that in endemic areas, acute meningitis is a potential manifestation of neurobrucellosis and that bilateral irreversible papillitis with ophthalmoparesis can be a potential serious complication.

Evaluation of the PANBIO Brucella immunoglobulin G (IgG) and IgM enzyme-linked immunosorbent assays for diagnosis of human brucellosis

PANBIO Brucella immunoglobulin G (IgG) and IgM enzyme-linked immunosorbent assays (ELISAs) were assessed against Brucella standard agglutination tube and Coombs tests. The sensitivities of ELISA IgG and IgM were 91% and 100%, respectively, while the specificity was 100% for both. These ELISAs are simple, rapid, and reliable for the diagnosis of human brucellosis.

Neurobrucellosis mimicking cerebral tumor: case report and literature review

We are reporting a case of neurobrucellosis that was clinically and radiologically indistinguishable from a cerebral tumor. The histological diagnosis was granulomatous encephalitis. The diagnosis was established by enzyme-linked immunosorbent assay (ELISA), detecting high levels of Ig G and Ig M Brucella antibodies in the serum and the cerebrospinal fluid. We suggest that patients with granulomatous encephalitis, without a clear etiological agent, should be studied for Brucella.

Comparison of the Brucella Standard Agglutination Test with the ELISA IgG and IgM in patients with Brucella bacteremia

The presumptive diagnosis of Brucellosis is based on a high or rising antibody titer measured by the Brucella Standard Agglutination Test (SAT). This tests does not discriminate between the immunoglobulin classes (IgG and IgM). The purpose of this study was to compare the diagnostic value of SAT with Brucella Enzyme Linked Immunosorbent Assay (ELISA) IgG and IgM tests in patients with Brucella bacteremia. Over a one-year period, we had 68 patients with clinical features suggestive of Brucellosis who had positive blood cultures for Brucella species. Sera were obtained from all of the patients as well as a control group of 70 healthy military personnel who were blood donors and had no symptoms of Brucellosis. Patients and blood donors originated from the same referral population. All the sera were tested by SAT and ELISA. All the 70 controls had a negative SAT. The sensitivity and specificity of the SAT test for the bacteremic patients were 95.6% and 100.0% respectively, while that of the ELISA IgG were 45.6% and 97.1%, and that of the ELISA IgM were 79.1% and 100.0% respectively. The sensitivity and specificity of either IgG or IgM positivity were 94.1% and 97.1% respectively. Assuming that the population prevalence of active Brucellosis in Saudi Arabia (SAT >or=1:320) is 5%, the positive and negative predictive values of SAT were 100% and 99.7% respectively; of ELISA IgG they were 45.2% and 97.1%; and of ELISA IgM they were 100% and 98.9%. When both the ELISA IgG and IgM were combined, the positive and negative predictive values were 63% and 99.6% respectively. In patients with Brucella bactremia, the sensitivity of either ELISA IgM or IgG were lower than SAT, however, combining IgM and IgG had similar sensitivity and specificity to SAT. The positive predictive value of SAT and IgM is satisfactory.

Detection of antibodies to Brucella cytoplasmic proteins in the cerebrospinal fluid of patients with neurobrucellosis

The diagnosis of human neurobrucellosis usually relies on the detection of antibodies to Brucella lipopolysaccharide (LPS) in cerebrospinal fluid (CSF) by agglutination tests or enzyme-linked immunosorbent assay (ELISA). Here we describe the detection of immunoglobulin G (IgG) to cytoplasmic proteins (CP) of Brucella spp. by ELISA and Western blotting in seven CSF samples from five patients with neurobrucellosis. While IgG to CP (titers of 200 to 12, 800) and IgG to LPS (800 to 6,400) were found in the CSF of these patients, these antibodies were not detected in CSF samples from two patients who had systemic brucellosis without neurological involvement. The latter, however, had serum IgG and IgM to both LPS and CP. No reactivity to these antigens was found in CSF samples from 14 and 20 patients suffering from nonbrucellar meningitis and noninfectious diseases, respectively. These findings suggest that, in addition to its usefulness in the serological diagnosis of human systemic brucellosis, the ELISA with CP antigen can be used for the specific diagnosis of human neurobrucellosis.

Central nervous system brucellosis: presentation, diagnosis and treatment

Although neurological symptoms in brucellosis are frequent, central nervous system (CNS) involvement is uncommon. Five patients with neurobrucellosis are presented. Three patients presented with meningoencephalitis, one with polyradiculoneuritis and one with myelitis and an eighth nerve palsy. All patients had lymphocytic pleocytosis, low glucose and elevated levels of protein in the cerebrospinal fluid (CSF). Gamma-globulin and IgG values in the CSF were also increased. Results of agglutination tests for Brucella in serum and CSF were positive for all patients, although titres were less in the CSF. Brucella melitensis was cultured from two patients. Treatment included concurrent administration of three of the following drugs: doxycycline, rifampicin, streptomycin, co-trimoxazole, ceftriaxone or ciprofloxacin. The three patients with meningoencephalitis fully recovered; the other two patients were left with minor disability.

Serological responses to brucellosis in HIV-seropositive patients

Serial sera from 2 patients infected with the human immunodeficiency virus (HIV) type 1 attending a clinic in Nairobi, Kenya, and with blood cultures yielding Brucella melitensis, were tested by enzyme-linked immunosorbent assay for their serological response (Brucella-specific immunoglobulin (Ig) M and IgG) to Brucella infection. Antibody responses were comparable to those of immunocompetent individuals, one patient showing serology typical of acute brucellosis, the other of chronic brucellosis. Sera from 100 other patients, 65 of whom were HIV-positive, attending the same clinic but whose routine microbiological cultures were negative for Brucella, were tested retrospectively for Brucella-specific antibody. Eight had Brucella-specific IgM and IgG, 6 had IgM only and 21 had IgG only, suggesting relatively high levels of exposure to Brucella in the study cohort. There was no association between Brucella antibody status and HIV status. Brucellosis is probably underdiagnosed in Kenya. Brucella serology may be helpful in the diagnosis of patients with non-specific symptoms in East Africa, regardless of HIV status.

Clinical and therapeutic features of childhood neurobrucellosis

Brucellosis is a multisystem disease with diverse clinical presentations, and involvement of the nervous system is considered to be rare in childhood. Five children with meningitis (n=2), meningoencephalitis (n=1), meningomyelitis (n=1), or cerebellar ataxia (n=1) are described, all of whom had a history of exposure to a possible source of brucellosis. Examination of cerebrospinal fluid (CSF) revealed lymphocytic pleocytosis in 4 patients, high protein concentration in 5 and low glucose concentration in 3. Reciprocal brucella agglutination titers were significantly elevated in serum (> or = 160) and in CSF (> or = 80) of all patients. Brucella melitensis was isolated from blood and CSF in one patient, from blood only in 2, and from bone marrow only in another one. All patients were treated successfully by a three-drug combination of streptomycin (4 patients) or doxycycline (one patient) with trimethoprim-sulfamethoxazole and rifampin, and in one patient dexamethasone was also added. In endemic areas, neurobrucellosis should be suspected in the evaluation of patients with unexplained neurologic symptoms.

Brucella melitensis growth on Loewenstein-Jensen egg medium from a case of Brucella meningitis

Bacteriologic investigation of a cerebrospinal fluid (CSF) specimen for mycobacteria on Lowenstein-Jensen egg medium revealed the presence of Brucella organisms. This coincided with a significant antibody titer against Brucella spp. This is the first documented report of the ability of B. melitensis organisms to grow on Loewenstein-Jensen egg medium.

Spinal cord compression due to Brucella granuloma

Central Nervous System (CNS) involvement during the course of Brucella infection is a rare clinical condition. In this article, a patient with a progressive paraparesis syndrome with spasticity, who was treated by medical methods and surgical intervention is analysed. This patient suffered from spinal cord compression in the thoracal region caused by a Brucella granuloma. The patient had no evidence of systemic Brucella infection.

Determination by enzyme-linked immunosorbent assay of immunoglobulin G (IgG), IgM, and IgA to Brucella melitensis major outer membrane proteins and whole-cell heat-killed antigens in sera of patients with brucellosis

An enzyme-linked immunosorbent assay was used to compare Brucella melitensis major outer membrane proteins (MOMP) and whole-cell heat-killed antigens (HK) in measuring antibrucella immunoglobulin G (IgG), IgM, and IgA in sera of brucellosis patients and controls. Antibodies to MOMP were generally similar to those against HK, and the correlation coefficients between the two antigens and IgG, IgM, and IgA in patients varied between 0.73 and 0.94. Both antigens are comparably suitable in detecting antibrucella immunoglobulin isotypes for the serologic diagnosis of patients with brucellosis, with high (greater than or equal to 95%) sensitivity and specificity.

Brainstem auditory evoked potential (BAEP) abnormalities in brucellosis

Twelve patients with neurobrucellosis and 17 patients with systemic brucellosis without neurological involvement underwent a brainstem auditory evoked potentials (BAEP) study. All neurobrucellosis patients (100%) showed abnormalities in their BAEP recordings, suggestive of brainstem lesions at various levels. On the other hand, only 5 (29%) of the 17 patients with systemic brucellosis had mild unilateral BAEP abnormalities, while the remaining 12 had normal responses. Comparison of pooled data between the systemic brucellosis and neurobrucellosis groups showed highly significant differences in all BAEP parameters. The recording of BAEP is thus considered a sensitive supplementary method to reveal CNS lesions in patients with neurobrucellosis.

Localized CNS brucellosis: report of 7 cases

Seven patients with brucellar infection localized in the central nervous system (CNS) are reported. This series represent 3.5% of all brucellosis cases in our hospital. There was a conspicuous absence of systemic signs and symptoms. The clinical course was characteristically protracted. Meningitis (acute, chronic, transient and recurrent) and progressive myeloradiculopathy were the 2 clinical patterns. Cranial nerve neuropathy was frequent, eight nerve involvement being present in 4 cases; transitory ischemic attacks and subarachnoid haemorrhage occurred in 2. Routine laboratory determinations were negative or non-specific. Cerebrospinal fluid (CSF) findings included hypoglycorrhachia, lymphocytic pleocytosis and hyperproteinorrhachia. There was also a remarkable increase in the gamma-globulin and IgG values with morphology of oligoclonal bands in CSF electrophoresis. Brucella agglutination titers were low or absent in serum and/or CSF. By contrast, Coombs tests were always positive and higher titers were found in serum and CSF. After treatment a persistent CSF positive Coombs test at low titers together with an isolated increase in CSF gamma-globulin and IgG values were detected in cured patients. Brucella blood cultures were negative, but CSF cultures were positive in four cases. Rifampin and doxycycline seems to be the treatment of choice. These agents must be maintained at least for 4 months in order to avoid relapses. Corticosteroids may be helpful at the beginning of treatment. Outcome is generally favourable in this disorder. We conclude that clinical and biological characteristics of localized CNS brucellosis are in accordance with those already described in other types of localized brucellosis.

Assessment of Brucellosis Card test in screening patients for brucellosis

The Brucellosis Card test (Brewers' Diagnostic Kits, Hynson, Westcott and Dunning, Inc., Baltimore, Md.) was evaluated in relation to the Brucelloslide test (bioMérieux, France), the microagglutination test (MAT) and the demonstration of brucella-specific IgG, IgM and IgA in an enzyme-linked immunosorbent assay (ELISA). A total of 573 serum specimens was tested. These included sera from patients with acute brucellosis (159), chronic brucellosis (23) and patients who had been diagnosed previously as having had brucella infection (155). Control groups consisted of patients with diseases other than brucellosis (52), others with non-infectious diseases (20), and healthy individuals (164). The Card test detected 100% of the patients with acute and 61% of the patients with chronic brucellosis. The sera from the control groups were all negative. Similar results were obtained with the Brucelloslide test and the MAT. The ELISA test detected brucella-specific Ig of all classes in the serum of patients with acute brucellosis, and IgG and IgA in the serum of patients with chronic brucellosis. In the latter group, IgM was also detected in 32% of the sera. Twenty-three per cent of sera with titres of 20 by the MAT were positive on the Card test and had ELISA titres for IgM, IgG and IgA of 400. Characterization of the antibodies involved in the Card test showed that sera with IgM ELISA titres of 1600, or an IgM titres of 800 together with IgG and IgA titres greater than or equal to 200 were Card test positive. Higher IgG (greater than or equal to 1600] plus IgA (greater than or equal to 400) titres were required to produce a positive Card test in the absence of IgM or when the IgM titre was less than or equal to 200. The Card test has a potential value as a rapid screening test for humans with acute brucellosis and shows similar results to Brucelloslide and MAT tests. ELISA, however, remains the most reliable test for diagnosis of brucellosis especially in patients with chronic and complicated stages of the disease.

The high rate of prevalence of CT-detected basal ganglia calcification in neuropsychiatric (CNS) brucellosis

Of 65 cases presenting with neuropsychiatric manifestations of brucellosis (CNS-brucellosis), 9(13.8%) had CT-detected basal ganglia calcification (BGC). Of these, 5 had meningitis and 4 had psychiatric manifestations as presenting features. The diagnosis of brucellosis was made by the finding of consistent history and physical findings and the presence of significantly elevated antibody titres and/or positive culture in the blood and/or CSF. In all the cases, BGC was in the form of punctate hyperdense non-enhancing shadows with average density 44.5-58.4 and maximum density 49-64HU. The calcification was unilateral in 3 cases, bilateral and symmetrical in 4 and bilateral but asymmetrical in 2. None of the cases had other predisposing conditions to BGC and in one of the cases did specific anti-brucella treatment effect a detectable change in the BGC. The finding of CT-detected BGC in patients coming from areas endemic for brucellosis should alert physicians to the possibility of underlying brucellar infection.

Evaluation of ELISA in the diagnosis of acute and chronic brucellosis in human beings

An enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of brucella-specific IgG, IgM and IgA in 173 patients with acute brucellosis, 22 patients with chronic brucellosis and in 281 controls consisting of 98 patients with other infectious etiologies, 20 patients with non-infectious diseases and 163 normal healthy adults. The ELISA results were compared with culture findings, the results of slide agglutination tests with Brucella melitensis (M), B. abortus (A) and Ross Bengal (RB) antigens, and of tube and microagglutination tests. Brucella cultures were positive in 53 and 5% of patients with acute and chronic brucellosis respectively. The slide agglutination tests with A, M, A plus M and RB antigens were positive in 42, 44, 51 and 98% of patients with acute brucellosis and in 23, 27, 27 and 64% of patients with chronic brucellosis. There was no significant difference in the results between the tube and microagglutination tests regardless of the type of antigen used. At a titre of greater than or equal to 80 or greater than or equal to 160 these tests were positive in 98% and 92% of patients with acute brucellosis and 60 and 40% of patients with chronic brucellosis. The brucella culture and agglutination tests were negative for all the controls. Brucella ELISA immunoglobulins (Ig) were detected in some individuals in the control groups but the majority of these had titres of less than or equal to 100 for IgG, IgM, and IgA. However, patients with brucellosis had significantly higher ELISA titres in all classes of Ig than controls but the sensitivity and specificity within each Ig class varied with the titre considered. At a titre of greater than or equal to 1600 the brucella IgG had a sensitivity and specificity of 98% for patients with acute or chronic brucellosis; this decreased with lower reciprocal titres. The brucella IgM titre of greater than or equal to 400 had a sensitivity of 98% and a specificity of 98% for patients with acute brucellosis. However, in patients with chronic brucellosis the brucella IgM was very low. The brucella IgA titre of greater than or equal to 200 showed a sensitivity of 98% and a specificity of 99% for patients with either acute or chronic brucellosis. This study indicates that brucella ELISA is a rapid, sensitive and specific assay, provides a profile of Ig classes in the diagnosis of acute and chronic brucellosis, is useful for mass screening and could be considered the method of choice for the serological diagnosis of brucellosis.