A high percentage of serum samples that test reactive by enzyme immunoassay for anti-Brucella antibodies are not confirmed by the standard tube agglutination test

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.

Evaluation of a New and Rapid Serologic Test for Detecting Brucellosis: Brucella Coombs Gel Test

BACKGROUND

Many serological tests have been used for the diagnosis of human brucellosis. A new serological method is identified as Brucella Coombs gel test based on the principle of centrifugation gel system similar to the gel system used in blood group determination. In this system, if Brucella antibodies were present in the serum, antigen and antibody would remain as a pink complex on the gel. Otherwise, the pink Brucella antigens would precipitate at the bottom of the gel card system.

OBJECTIVE

In this study, we aimed to compare the Brucella Coombs gel test, a new, rapid screen and titration method for detection of non-agglutinating IgG with the Brucella Coombs test.

MATERIALS AND METHODS

For this study, a total of 88 serum samples were obtained from 45 healthy persons and 43 individuals who had clinical signs and symptoms of brucellosis. For each specimen, Rose Bengal test, standard agglutination test, Coombs test and Brucella Coombs gel test were carried out.

RESULTS

Sensitivity and specificity of Brucella Coombs gel test were found as 100.0 and 82.2%, respectively.

CONCLUSION

Brucella Coombs gel test can be used as a screening test with high sensitivity. By the help of pink Brucella antigen precipitation, the tests' evaluation is simple and objective. In addition, determination of Brucella antibody by rapid titration offers another important advantage.

2015 Infectious Diseases Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adultsa

These guidelines are intended for use by infectious disease specialists, orthopedic surgeons, neurosurgeons, radiologists, and other healthcare professionals who care for patients with native vertebral osteomyelitis (NVO). They include evidence and opinion-based recommendations for the diagnosis and management of patients with NVO treated with antimicrobial therapy, with or without surgical intervention.

Detection of IgM antibrucella antibody in the absence of IgGs: a challenge for the clinical interpretation of brucella serology

The use of enzyme-linked immunosorbent assay (ELISA) for the detection of IgG and IgM antibodies antibrucella has become widespread in the diagnosis of human brucellosis. IgM anti-Brucella antibodies are indicative of acute infection. Between 2009-2013, 5307 patients were evaluated for serologic diagnosis at the Microbiology Laboratory of the Albacete General Hospital. A ELISA IgM-positive, IgG-negative anti-Brucella antibody serology pattern was detected in 17 of those patients. Epidemiology data, symptoms, laboratory data, treatment and outcome from these patients were reviewed. Sixteen patients presented with musculoskeletal pain, fatigue and/or fever and 1 was asymptomatic. Five patients received treatment with doxycycline combined with rifampin, gentamycin or streptomycin during 6-12 weeks, with no improvement. None of the 17 patients were finally diagnosed with brucellosis. Our results indicate that anti-Brucella IgM positive serology, per se, is not enough to diagnose acute brucellosis and other methods should be used for confirmation. Brucella serology data should be interpreted taking into account the patient's clinical history and epidemiological context.