Serological response of chickens to Salmonella thompson and Salmonella pullorum infections.

Chickens were experimentally infected with Salmonella thompson (serogroup C, paratyphoid) and Salmonella pullorum (serogroup D). Five serological methods and one cultural method were used in detecting the infections. The microantiglobulin test was superior to all other methods for detection of paratyphoid (S. THOMPSON) infection and was followed in efficacy by the microagglutination test, rapid serum plate test, cloacal swab culture, macroscopic tube agglutination test, and rapid whole-blood test, in that order. Birds infected with S. pullorum showed much higher agglutinin titers than the birds infected with paratyphoid. The microagglutination and microantiglobulin tests were not significantly different for detection of pullorum infection and were followed in efficacy by the rapid serum plate, macroscopic tube agglutination, rapid whole-blood, and cloacal swab culture tests, in that order. The cloacal swab culture test was totally inadequate for the detection of pullorum infection.     

Comparison of microagglutination with the indirect immunofluorescence assay for the diagnosis of infection withLegionella pneumophila serogroup 1

A comparison was made of the indirect immunofluorescence assay and microagglutination in the diagnosis of infections caused byLegionella pneumophila serogroup 1. Control sera consisted of 709 sera from patients without pneumonia and 99 sera from patients with mycoplasma or clamydia infection. The 468 test sera were from 51 patients with serologically confirmed or suspectedLegionella pneumophila serogroup 1 infection, and from 230 patients with pneumonia of unknown aetiology. There was good agreement between the results of the two methods for detection of antibodies toLegionella pneumophila serogroup 1. However, contrary to what is currently reported in the literature, microagglutination was the more sensitive method in this study, especially if the first serum samples were compared. The detection of IgM by microagglutination probably explains this increased sensitivity.     

Microagglutination test for early and specific serodiagnosis of tularemia

A microagglutination test with safranin-stained Francisella tularensis antigen was compared with a conventional tube agglutination test for the serodiagnosis of tularemia. The microagglutination test was performed in round-bottom microtiter plates by using 0.025 ml of the antisera and of the antigen. The antibody titers obtained by using the microagglutination test were 8 to 64 times higher than those seen with the tube agglutination. By the microagglutination test, the serum agglutinins were detected 3 days earlier in rabbits and 9 days earlier in humans than by the tube agglutination test. The microagglutination test also detected residual circulating antibodies in humans more than 20 years after recovery from infection. These early agglutinins were shown to be in the immunoglobulin M class because of their sensitivities to 2-mercaptoethanol. No significant group agglutination reaction with Brucella abortus was observed. These observations indicate that the microagglutination test is a useful tool for the early and specific serodiagnosis of tularemia.     

Evaluation of a safranin-O-stained antigen microagglutination test for francisella tularensis antibodies

A microagglutination test for Francisella tularensis, with 0.025-ml amounts of diluted sera and 0.025-ml amounts of safranin-O-stained antigen in U-bottom microtitration plates, was compared with a tube agglutination test by using 137 sera. There was 86.3% agreement (+/- 1 dilution variation) between the microagglutination results and the tube agglutination results for sera with tube agglutination titers of greater than or equal to 20. There was 100% agreement (+/- 1 dilution variation) for sera with titers of less than 20. The advantages of the microagglutination test are: (i) it requires fewer man hours to perform; (ii) it requires only one-twentieth of the amount of antigen; and (iii) it is easier to read.     

Safranin O-stained antigen microagglutination test for detection of brucella antibodies.

A microagglutination test was compared with a standard tube agglutination test for the detection of brucella antibodies. Advantages of the microagglutination test were that it required less time to perform, had a shorter incubation period, and used less antigen.     

Evaluation of sensitivity of two serological tests for diagnosing pneumonia caused by Legionella pneumophila serogroup 1.

The sensitivity of an indirect immunofluorescence antibody test (IFAT) and a rapid microagglutination test (RMAT) for the diagnosis of Legionnaires' disease caused by Legionella pneumophila serogroup 1 was evaluated using serum specimens from 119 patients with bacteriologically confirmed infections. The sensitivity of both assays was found to be about 80%. In addition, antibody titres suggestive of L pneumophila infection were found in 40% of patients in the first week after admission to hospital. These data show that both assays can be used with confidence in the early diagnosis of Legionnaires' disease.     

Detection of antibodies to legionnaires disease organism by microagglutination and micro-enzyme-linked immunosorbent assay tests.

Microagglutination and micro-enzyme-linked immunosorbent assay (ELISA) tests with easily prepared, safe, heat-killed antigens for detecting antibodies to the legionnaires disease organism have been developed. A safranin-stained whole-cell antigen is used in the microagglutination test, and a simply prepared soluble antigen is used in the micro-ELISA tests. The microagglutination test detected elevated titers in 97.2% of the sera from patients with legionnaires disease. Three variations of the micro-ELISA test with anti-human immunoglobulin G, immunoglobulin M, and Fab peroxidase-labeled conjugates revealed elevated titers with 74.3, 82.9, and 88.6% of the sera, respectively. The microagglutination and the micro-ELISA tests used in combination detected 100% of the elevated titers.     

Simple, speedy, sensitive, and specific serodiagnosis of pertussis by using a particle agglutination test.

We developed a particle agglutination test (KPA) with poly(gamma-methyl L-glutamate) as the solid particle for measurement of pertussis toxin (PT) antibody. In this study, KPA was assessed as a means of serodiagnosing pertussis, and the results were compared with those of indirect enzyme-linked immunosorbent assay (indirect ELISA) and the microagglutination test. First, four serum samples were collected from each of 21 healthy children: before and 4 weeks after receiving three primary doses of acellular pertussis vaccines and before and 4 weeks after receiving a booster dose. In all 21 vaccinees, a significant rise in PT antibody titers was observed by KPA after each vaccination, and among all 84 serum samples collected, an excellent correlation was demonstrated between the values obtained by indirect ELISA and those obtained by KPA (r = 0.92). Second, paired serum samples were collected at intervals of approximately 2 weeks from 51 patients with culture-confirmed pertussis. A significant increase in titer (fourfold or more) was observed in 39 (76%) patients by KPA, 34 (67%) patients by indirect ELISA, and 23 (45%) patients by the microagglutination test. In acute- and convalescent-phase sera collected from 20 nonpertussis patients, there were no changes in titers by KPA. The KPA procedure was as simple as that of the microagglutination test, and the reaction time was only 2 h (or overnight). In this study, KPA was demonstrated to be a simple, speedy, sensitive, and specific serodiagnostic method for pertussis.     

Pulsed-field gel electrophoresis of NotI digests of leptospiral DNA: a new rapid method of serovar identification.

Fingerprints for 72 reference serovar strains of pathogenic Leptospira spp. were obtained by pulsed-field gel electrophoresis (PFGE) following NotI restriction digests of the chromosome. These strains included the serovar reference strains of serogroups Australis, Ballum, Bataviae, Grippotyphosa, Panama, Pomona, and Pyrogenes. Sixty-four serovars could be identified by a unique NotI restriction profile. The remaining serovars were differentiated by chromosomal digestion with SgrAI. These included four serovars from serogroup Australis, two serovars from serogroup Ballum, and two serovars from serogroup Bataviae. Thirteen of 18 recent clinical isolates identified by microagglutination test and cross-adsorption procedure were correctly typed by PFGE. The results indicate that PFGE, which is considerably more rapid than serology, should be useful for identification and epidemiological studies.     

Suitability of Coxiella burnetii strains for preparation of phase II artificial diagnostic antigen for microagglutination test.

Sensitivity in the microagglutination (MA) test of artificial (prepared by potassium periodate treatment) phase II Coxiella burnetii antigens depended on the C. burnetii strain used and the number of its chick embryo yolk sac passages.     

Background prevalence of microagglutination antibodies to Legionella pneumophila serogroups 1, 2, 3, and 4.

The background prevalence of microagglutination antibodies to Legionella pneumophila was determined by testing the sera of 517 individuals who lived or worked in a small Iowa town. In this population, the upper limit of normal microagglutination titer for serogroups 1, 3, and 4 was 1:16, and that for serogroup 2 was 1:8. The prevalence of microagglutination titers of greater than or equal to 1:32 against any serogroup of L. pneumophila was only 7.4% and did not vary significantly with age or sex.     

Serological characterization of Proteus penneri species novum.

Serological characterization of the first collection of the 20 Proteus penneri strains is presented. All anti-0 sera were examined in microagglutination, semi-quantitative precipitation and passive hemagglutination tests. Some P. penneri lipopolysaccharides showed strong cross-reactivity in passive hemagglutination additionally confirmed by inhibition in this test. Serological similarity between species within genus Proteus is discussed.     

Effect of centrifugation and microagglutination techniques on Brucella agglutinin titers.

The microagglutination technique without centrifugation was more effective than centrifugation of the standard tube test for increasing Brucella agglutinin titers of specimens with a titer greater than or equal to 160 but was less effective than centrifugation of the standard tube test for specimens with a titer less than 160.     

Evaluation of microagglutination test for differentiation between Serpulina (Treponema) hyodysenteriae and S. innocens and serotyping of S. hyodysenteriae.

Swine dysentery is a mucohemorrhagic diarrheal disease caused by the anaerobic spirochete Serpulina hyodysenteriae. At present, the serotyping is done by immunodiffusion testing with lipopolysaccharide (LPS) extract as antigen and rabbit hyperimmune sera produced against different serotypes of S. hyodysenteriae. Since the preparation of LPS is time-consuming and requires a large quantity of bacteria, it is desirable to use a serotyping method which does not require the extraction of LPS. In the present investigation, microagglutination was evaluated by using both formalinized whole- and boiled-cell suspensions as antigens and rabbit hyperimmune sera produced against formalinized whole-cell suspensions of reference strains of S. hyodysenteriae and S. innocens B256. Use of boiled cell suspension as antigen permitted the differentiation between isolates of S. hyodysenteriae and S. innocens as well as serotyping of S. hyodysenteriae strains accurately. A total of 18 isolates were identified as S. hyodysenteriae, and 3 isolates were identified as S. innocens. The microagglutination test was found specific, sensitive, and easy to perform; thus, it was judged suitable for routine identification and serotyping of S. hyodysenteriae isolates.     

Affinity chromatography of antiserum to a gram negative organism

An immunoadsorbent method is described for the purification of antibody directed against gram negative bacteria. Two anion exchange materials were compared for their ability to immobilize whole cells of Veillonella alcalescens, a gram negative oral bacterium. Purified antibody preparations were applied to the columns and subsequently eluted with various combinations of desorbing buffers. The quantity of recovered antibody was measured and its activity assayed, using a microagglutination technique. The highest levels of protein and specific antibody activity were recovered from Dowex-1-acetate columns desorbed by a combination of borate buffer pH 10 and 3 M KSCN pH 6, followed by levels of specific antibody activity obtained from a DEAE cellulose column desorbed by glycineHCl, pH 2.3.     

Suitability of the microagglutination test for detection of post-infection and post-vaccination Q fever antibodies in human sera

Serological examination by the microagglutination (MA) and complement-fixation (CF) tests of human sera collected before and after vaccination with Q fever chemovaccine revealed a higher sensitivity of the MA test for detecting both pre-vaccination antibodies reflecting a previous exposure to Q fever and post-vaccination antibodies reflecting vaccine immunogenicity. In persons serologically positive before vaccination the level of post-vaccination MA antibody response was indirectly proportional to the titres of prevaccination MA antibodies.     

Antibody response to Rocky Mountain spotted fever.

Various techniques were compared to determine the most sensitive method for detection of rocky Mountain spotted fever antibody. A radiometabolic technique for detection of Rocky Mountain spotted fever antibody is also described. In infected monkeys, the fluorescent antibody technique yielded the earliest evidence of seroconversion; with some monkeys the microagglutination procedure was equally effective. The fluorescent antibody and microagglutination measurements showed higher titers than those for complement fixation, Weil-Felix, or the radiometabolic techniques.     

Evaluation of seven tests for diagnosis of human brucellosis in an area where the disease is endemic

The results of seven serologic tests for diagnosis of human brucellosis were evaluated. The titrated Rose Bengal test, microagglutination test, microtiter-adapted Coombs test, and immunocapture-agglutination test (Brucellacapt) were positive for all sera from patients with acute brucellosis. The immunoglobulin G (IgG), IgM, and IgA commercial enzyme immunoassays (ELISAs) failed to show specific antibodies in 3 patients, 10 patients, and 1 patient, respectively. The sensitivity of ELISA is not higher than that of conventional tests.     

Immune response to Bacteroides ureolyticus in a patient with brain abscess

A high titer (1:256) of agglutinating antibodies against Bacteroides ureolyticus was demonstrated in a 35-year-old woman with brain abscess, using a microagglutination test. Tests done with B. ureolyticus and heterologous sera as well as with heterologous strains and the patient's serum were negative. Circulating antibody to B. ureolyticus has not been reported previously.     

Comparison of the microagglutination test with bactericidal response to Legionella pneumophila (Legionnaires disease bacterium).

This investigation found that individuals with microagglutination antibody titers of 1:32 or greater to Legionella pneumophila produced bactericidal activity against the bacterium. Those individuals with microagglutination antibody titers of 1:16 or less demonstrated no bactericidal activity.