Evaluation of beckman antistreptolysin O and antideoxyribonuclease B (ASO/ADB) test kit.

The Beckman antistreptolysin O kit agreed within one-dilution increment for 70% of the specimens tested. The antideoxyribonuclease B kit agreed within onedilution increment for 96% of the specimens tested.

Evaluation of the Wampole Streptonase B test.

The Streptonase B test was compared with the Center for Disease Control streptococcal anti-deoxyribonuclease B test. A total of 96% of anti-deoxyribonuclease B titers obtained with the Streptonase B test were within +/- 1 dilution step of those obtained with the Center for Disease Control anti-deoxyribonuclease B test.

Cross-reaction to Legionella pneumophila antigen in sera with elevated titers to Pseudomonas pseudomallei.

A significantly greater incidence (P less than 0.005) of Legionella pneumophila microagglutination titers greater than or equal to 32 was found in sera with elevated titers to Pseudomonas pseudomallei as compared with sera with negative titers for P. pseudomallei antibodies. The greater incidence of L. pneumophila titers in these sera suggests that L. pneumophila and P. pseudomallei share an antigen. The incidence of L. pneumophila microagglutination titers of greater than or equal to 32 in sera with elevated titers to Brucella abortus or Francisella tularensis is not statistically significant.

Determination of brucella immunoglobulin G agglutinating antibody titer with dithiothreitol.

The routine brucella agglutination test measures both immunoglobulin M (IgM) and IgG brucella antibody titers; however, only an elevated IgG titer is significant for differentiating active from inactive disease in patients with symptoms lasting 3 or more weeks. The IgG antibody titer can be determined by treating the serum wih 2-mercaptoethanol to inactivate the IgM brucella antibodies while leaving the IgG brucella antibodies intact. Dithiothreitol, which also inactivates IgM, was compared with 2-mercaptoethanol for the determination of IgG brucella agglutination titers. The dithiothreitol and 2-mercaptoethanol test results agreed within +/- 1 dilution step in 103 of 105 serum specimens tested, for a 98.1% rate of agreement. The results indicate that dithiothreitol can be used in place of 2-mercaptoethanol for determining IgG brucella agglutination titers. Dithiothreitol does not have the offensive odor or the irritant properties of 2-mercaptoethanol.

Reduction of Brucella species and Francisella tularensis cross-reacting agglutinins by dithiothreitol.

Cross-reaction agglutinin titers to Brucella abortus antigen were found in 42 of 128 tularemia serum specimens, and cross-reaction titers to Francisella tularensis antigen were found in 8 of 34 brucellosis serum specimens. The cross-reaction titers were reduced to 10 or less by dithiothreitol, suggesting that the titers are due to immunoglobulin M antibody.

Comparison of the streptozyme test with the antistreptolysin O, antideoxyribonuclease B, and antihyaluronidase tests.

The streptozyme test was compared with the antistreptolysin O (ASO), antideoxyribonuclease B (ADN-B), and antihyaluronidase (AH) tests. One hundred and twenty-seven human serum specimens were tested by each of the four tests. The streptozyme test detected more specimens with elevated titers than any single test; however, it was not as effective as the combination of the ASO and ADN-B tests. The streptozyme test appears to be particularly useful for laboratories which rely solely on the ASO test for serological evidence of a streptococcal infection. The test can be used in these laboratories to screen all specimens with low ASO titers (<170) for the detection of ADN, AH, antinicotinamide adenine dinucleotidase, and antistreptokinase.

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.

Upper limit of normal titer for detection of antibodies to Legionella pneumophila by the microagglutination test.

An upper limit of normal microagglutination titer for the Knoxville strain of Legionella pneumophila was determined by testing 830 sera. The upper limit of normal titer was found to be 8; however, we suggest that when applied to single serum specimens a titer of 32 be considered the lowest titer suggestive of infection (not necessarily disease).

"Upper limits of normal" antistreptolysin O and antideoxyribonuclease B titers.

"Upper limits of normal" antistreptolysin O (ASO) and antideoxyribonuclease (ADN) B titers were determined on serum specimens from various age groups of pediatric patients with no history of a recent streptococcal infection and on healthy adult hospital employees. The upper limit of normal value is that level of antibody titer exceeded by no more than 15% of the total subjects in each age group. This value varies with the age of the subject, and the most pronounced differences are between the values of preschool age children, school age children, and adults. The upper limit of normal values for these groups were as follows: preschool age, ASO = 85(100); ADN B = 60(50); school age, ASO = 170(166); ADN B=1 70(166); and adult, ASO = 85(100); ADN B = 85(100).

Comparison of antistreptolysin O latex screening test with the antistreptolysin O hemolytic test.

This report describes a comparison of the Behringwerke antistreptolysin O (ASO) latex screening test with the ASO hemolytic test. Agreement between the two tests was poor when Difco streptolysin O (SLO) reagent was employed in the hemolytic test; approximately 34% of the sera with ASO titers in the normal range of the hemolytic test gave false-positive latex test reactions. However, the percentage of false-positive latex test reactions was only 5% when Behringwerke SLO reagent was used in the hemolytic test. An assay of the Difco and Behringwerke SLO reagents against an ASO standard indicated that the Difco SLO reagent was more potent than the Behringwerke SLO reagent. The lack of agreement between the Behringwerke latex test and the hemolytic test using Difco SLO reagent is attributed to the potency of the SLO reagents.

Susceptibility of the Lyme disease spirochete to seven antimicrobial agents.

The antimicrobial susceptibility of five Lyme disease spirochete strains (two human and three tick isolates) was determined. A macrodilution broth technique was used to determine on three separate test occasions the minimal inhibitory concentrations (MICs) of seven antibiotics. The Lyme disease spirochete was most susceptible to erythromycin with a MIC of less than or equal to 0.06 micrograms/ml. The spirochete was also found to be susceptible to minocycline, ampicillin, doxycycline, and tetracycline-HCL with respective mean MICs of less than or equal to 0.13, less than or equal to 0.25, less than or equal to 0.63, and less than or equal to 0.79 micrograms/ml. The spirochete was moderately susceptible to penicillin G with a mean MIC of 0.93 micrograms/ml. All strains were resistant to rifampin at the highest concentration tested (16.0 micrograms/ml).

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.

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.

Time--domain analysis in gated cardiac blood pool studies.

A technique is presented for producing functional images derived from equilibrium gated blood pool studies as a means of diagnosing cardiac disease. These functional images are based on characteristics associated with the time variation of the count rate (the time domain) at each point of the image matrix rather than on the Fourier transform of the time-activity curve (the frequency domain) which has gained recent attention. As examples of this method, we present images which display the statistical variance of the time-activity curve at each pixel, corrected for the expected contribution due to random statistical fluctuation, and images which display the time at which each pixel reaches its minimum count value. Variance and time-to-minimum images are comparable to Fourier amplitude and phase images, respectively, and have been found to be useful in facilitating the diagnosis of wall motion abnormalities. A major advantage of time-domain analysis is the wide variety of features of potential clinical significance which may be investigated.

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.

Micro test for streptococcal anti-deoxyribonuclease B.

A methyl green decolorization micro test for the determination of streptococcal anti-deoxyribonuclease B titers in serum is described. The micro test was compared with an alcohol precipitation macro test on 112 human sera. The anti-deoxyribonuclease B titers agreed within one dilution step for 85.7% of the 112 sera examined by both techniques. Both tests were about equal in the detection of titers above the upper limits of normal. The micro test requires smaller amounts of reagents and fewer man-hours to perform than the macro test. This translates into lower cost per test and more tests per man-hour.

Effect of type of red blood cells on antistreptolysin O titer.

Antistreptolysin O (ASO) titers were determined on 117 human sera with rabbit, human, and sheep red blood cells (RBC) as the indicator system in the ASO tube test. The titers of 65% of the sera were one dilution step higher when a 5% suspension of sheep RBC was used instead of a 5% suspension of rabbit RBC. Titers were one dilution step higher in 42.7% of the sera when a 5% suspension of human RBC was used instead of a 5% suspension of rabbit RBC. The best comparability of titers was between a 5% suspension of human RBC and a 2.5% suspension of sheep RBC.

Immunoglobulin specificity of the microagglutination test for the Legionnaires' disease bacterium.

Differences in results of microagglutination tests for the Legionnaires' disease bacterium on untreated sera and sera treated with 2-mercaptoethanol suggest that, like other agglutination tests, the microagglutination test is heavily dependent on the presence of IgM antibody.

Lyme disease: a selective medium for isolation of the suspected etiological agent, a spirochete.

A simple procedure with a new selective culture medium for the isolation of the suspected etiological agent of Lyme disease from ticks is described. Live ticks (Ixodes dammini) were ground with a mortar and pestle, and the suspensions were inoculated into a selective and nonselective medium. The selective medium, which contained kanamycin and 5-fluorouracil, yielded positive spirochete cultures from 100% of the pooled ticks and from 79% of the single tick specimens. The isolation rate for the nonselective medium was 0% from the tick pools and 58% from the single tick specimens.