Techniques and Interpretations in the Serological Diagnosis of Brucellosis in Man

Abstract

and § Public Health Laboratory, PrestonB R U C E L L O S I S presents in three forms-acute brucellosis, chronic brucellosis following an acute attack and chronic brucellosis of insidious onset. Because the rate of isolation of Brucella abortus from blood or tissues is low, laboratory diagnosis of this disease is based mainly on the results of serological tests, the results of which depend on the clinical form and stage of the infection. The use of some of these tests in chronic brucellosis has already been discussed (Kerr, Coghlan, Payne and Robertson, 1966a and b).The variety of technical procedures employed at present leads to results that cannot be equated between laboratories. The purposes of this paper are to present details of these tests so that comparable results may be obtained and to indicate the way in which the results may be interpreted to help to determine the stage of the infection. The paper is presented in two parts; the first deals with a description of the tests and the second with their interpretation. There is also an appendix in which certain technical minutiae omitted from the main text may be referred to. The following tests are dealt with: (A) the standard agglutination test ; (B) the mercaptoethanol test (agglutination in the presence of 2-mercaptoethanol) ; (C) the anti-human globulin (Coombs) test (AHG test) for non-agglutinating antibodies ; (D) the complement fixation (CF) test. TECHNICAL PROCEDURESIn all cases Brucella abortus (BY. abortus) agglutinable suspensions are used for the tests, but in certain circumstances, to be discussed later, Brucella melitensis (Br. melitensis) suspensions are included. The standard agglutination test Mate vialsAntigen. Three different Br. abortus suspensions have been available to the authors for investigation. They are " Weybridge " standardised BY. abortus " agglutination concentrate", produced by the Veterinary Laboratories of the Ministry of Agriculture, Fisheries and Food, Weybridge, England; Br. abortus " concentrated 0 suspension " produced by the Standards Laboratory, Central Public Health Laboratory, London (PHLS); and " Wellcome " Br. abortus " agglutinable concentrated smpension " produced by Burroughs Wellcome and Co. These three suspensions differ in their cell concentrations, and since an inverse linear relation exists between the concentration of the bacterial cells and the

Enzyme immunoassay of the antibody response to Brucella andYersinia enterocolitica09 infections in humans

“…Antibody determinations for the diagnosis of brucellosis, like the direct and mercapto-ethanol agglutination tests, complement fixation tests and Coombs' test (Kerr et al 1968) all employ whole bacterial cells with their multitude of antigenic determinants. The results of these tests have not always been easy to interpret.…”

Serum antibody response in acute brucellosis

“…Chronic brucellosis is a poorly defined clinical state and, when suspected, laboratory confirmation is frequently requested. Kerr et al (1968) described an AHG test based on that of Wilson & Merrifield (1951) and advocated its use in the diagnosis of chronic brucellosis. They stated that a positive AHG test when accompanied by CF antibodies and taken in conjunction with clinical evidence may support a diagnosis of chronic brucellosis.…”

“…Each serum was titrated to at least 1/640 to avoid errors due to prozone phenomena. The tubes were kept at 370 C. for 2 days in a covered water bath and read in indirect light in a viewing box according to the criteria described by Kerr et al (1968). The titre was recorded as the reciprocal of the highest dilution of serum to give partial or complete agglutination.…”

“…The tests were set up in WHO plastic plates using a four-volume technique with veronal buffer as diluent, and serum dilutions starting at 1/10. The B. abortuus antigen (PHLS) was diluted 1/60 (this was found to be the optimal concentration using the method described by Kerr et al 1968). The haemolytic system was standardized and prepared as described by Bradstreet & Taylor (1962).…”

Human Brucellosis in Macedonia – 10 Years of Clinical Experience in Endemic Region

“…The diagnosis was based on clinical findings compatible with brucellosis (arthralgia, fever, sweating, malaise, hepatomegaly, splenomegaly, signs of focal disease), supported by detection of specific antibodies at significant titers and/or demonstration of at least a 4-fold rise in antibody titer in serum samples obtained 3-4 weeks apart. Antibody titers were determined by standard tube agglutination (STA), Brucella Coombs test (9,10), or the Brucellacapt assay (11). The corresponding titers considered positive were ≥1/160, ≥1/320, and >1/320, respectively.…”