DNA probe detection of Eikenella corrodens, Wolinella recta and Fusobacterium nucleatum in subgingival plaque.

This cross-sectional study used species-specific DNA probes to examine subgingival plaque specimens for the presence of Eikenella corrodens, Wolinella recta, and Fusobacterium nucleatum in adults with untreated periodontitis or gingivitis and in healthy controls. W. recta and F. nucleatum were more prevalent in diseased sites from the periodontitis group when compared with the controls (81% vs 22% and 83% vs 20% respectively). E. corrodens was detected in 62% of the control sites and 81% of the periodontitis sites. Because the control sites commonly contained this organism, E. corrodens may not be useful in differentiating between health and disease. In addition, the relationship between the prevalence of W. recta and F. nucleatum and the prevalence of the established periodontal pathogens, Actinobacillus actinomycetemcomitans, Bacteroides intermedius and Bacteroides gingivalis, was examined. Positive detection of W. recta and F. nucleatum correlated closely with the presence of A. actinomycetemcomitans, B. intermedius and B. gingivalis. Therefore, W. recta and F. nucleatum do not appear to be unique indicators of periodontal disease.

DNA probes in the diagnosis of periodontal microorganisms.

The need for a rapid and sensitive microbiological assay has become necessary for both research and clinical diagnostic purposes. This need has become clear as a result of extensive documentation linking specific bacterial species and periodontal destruction. DNA probe technology provides both a sensitive and specific assay and alleviates the concern for transport of fastidious microorganisms. The DNA probe procedure includes (1) disruption of bacterial cells with denaturation of DNA, (2) immobilization of DNA onto a nitrocellulose filter, (3) blocking unbound nitrocellulose with non-specific DNA, (4) hybridization of the filter with 32P-labelled probe, (5) washing and detection of bound probe. At our laboratory, microbiological analysis with whole-genomic and cloned DNA probes has been used on thousands of plaque specimens in several large-scale research projects. In one study, levels (greater than or equal to 10(5)) of Actinobacillus actinomycetemcomitans were significantly higher in subjects under 21 yr than in subjects with adult periodontitis (over 21 yr old). In another study, the distribution of periodontal pathogens throughout the mouth was examined. High levels were selectively found at sites with probing depths of 5 mm or more and bleeding on probing, directing specimen collection to these sites. In contrast, random selection of sites for sampling was found to be a poor method for detecting high levels of pathogens. These data suggest appropriate sites for specimen collection for further research and diagnostic purposes.

Evaluation of the DMS Rapid E system for identification of clinical isolates of the family Enterobacteriaceae.

A total of 387 unique clinical isolates of the family Enterobacteriaceae were examined with the new DMS Rapid E gram-negative identification system (DMS Laboratories, Inc., Flemington, N.J.) and the API 20E procedure (Analytab Products, Plainview, N.Y.). Altogether, 376 strains (97.2%) were correctly identified to species level within 4 h with the DMS Rapid E system; 366 strains (94.6%) were correctly identified with the API 20E after overnight incubation.

Detection of cytomegalovirus antibody with two commercially available assays, an indirect hemagglutination test and an enzyme immunosorbent assay.

By the use of two reference procedures, an indirect hemagglutination assay and a complement fixation test, the presence or absence of cytomegalovirus (CMV) antibody was determined for 221 human sera. Ninety-nine sera (44.8%) were found to contain CMV antibody. The remaining 122 sera (55.2%) lacked detectable CMV antibody. These same sera were then analyzed by two recently introduced, commercially available CMV antibody assays, an indirect hemagglutination test (IHA-c; Cetus Corp., Emeryville, Calif.) and an enzyme-linked immunosorbent assay (ELISA; M. A. Bioproducts, Walkersville, Md.). With the results of the reference procedures as true evidence of the presence or absence of CMV antibody, the sensitivity of the IHA-c was found to be 100%; the specificity was 98.4%. The sensitivity of the ELISA was also 100%; the specificity was 96.7%. The overall accuracies of these procedures were 99.1 and 98.2%, respectively. Time and motion studies revealed the IHA-c procedure to be faster and technically less demanding than the ELISA procedure.

Comparison of the API 20S Streptococcus identification system with an immunorheophoresis procedure and two commercial latex agglutination tests for identifying beta-hemolytic streptococci.

The API 20S Streptococcus identification system and a new immunorheophoresis procedure were evaluated as means for determining the Lancefield serogroup of beta-hemolytic streptococci recovered from human clinical specimens. The serogroup of 96 strains was determined by these methods and by two commercially available latex agglutination tests. Streptex and SeroSTAT. The results of all four procedures were compared with the results of a classical precipitin test. The API 20S system correctly categorized 92.7% of the isolates; 94.8% were correctly identified by the immunorheophoresis procedure. The latex agglutination procedures were of comparable accuracy, yielding correct identifications with approximately 92% of the strains tested.