Fluorescent antibody and flagella stains for rapid detection of bacteria at periodontally healthy and diseased sites.

Two rapid methods of identifying bacteria associated with periodontal disease were investigated to determine their diagnostic usefulness in longitudinal or epidemiologic studies. Three nonmotile organisms were identified by fluorescent antibody stains (FA) while percentages of motile bacteria were assessed by counting all spirochetes, flagellated and nonflagellated organisms stained with a simplified silver-plating stain for flagella. Relationships between disease activity and these bacteria from subgingival plaque samples taken at 18 individual sites (12 diseased, 6 healthy) were determined by correlating the quantity of detectable bacteria with the Gingival Index (GI), Plaque Index (PLI) and probing depth (PD). The highest correlations found with the FA stains were between Bacteroides gingivalis and probing depth (rs = 0.85), GI (rs = 0.80) and PLI (rs = 0.80). Bacteroides melaninogenicus and/or Bacteroides intermedius also correlated well with the GI (rs = 0.66), PLI (rs = 0.64), and PD (rs = 0.59), but to a lesser degree than B. gingivalis. Flagella stains showed that spirochetes correlated highly with PD (rs = 0.82), as did the total motile group with PLI (rs = 0.82). Motile bacteria alone were only moderately associated with the clinical parameters measured. The results of this investigation suggest that FA- and flagella-staining methods can be valuable screening tools for the detection of bacterial species and motile organisms in longitudinal or epidemiologic studies.

Misdiagnosis caused by fungal contaminant in a histological stain solution.

Silver stains on tissue and cytology specimens are important in the evaluation of patients with suspected fungal infections. Care must be taken, however, to prevent misinterpretation of contamination artifacts. Two cases presenting such a problem are reported. The first patient had granulomatous leg lesions that microscopically showed characteristics of erythema induratum but with budding yeastlike organisms demonstrated by Grocott methenamine silver stain. Cultures and subsequent biopsies were negative for fungi. The second patient had a steroid-dependent chronic obstructive lung disease, and during evaluation for possible Pneumocystis carinii pneumonia, the Grocott methenamine silver stain on expectorated sputum showed budding yeastlike organisms. Sputum cultures were negative for fungi. Examination of the two Grocott light-green counterstain solutions demonstrated black, budding yeast cells similar to those seen in the specimens from the patients. Culture of the counterstain grew Exophiala (Phialophora) jeanselmei. Further studies revealed that this cause of misdiagnosis could be prevented by either filtering or adding thymol to the counterstain solution. Care regarding contamination of histological stain solutions is emphasized.

Comparison of media for detection of fungi on spacecraft.

Five media, including Trypticase soy agar (TSA; BBL) pour plates, spread plates of TSA, Mycophil agar with chloromycetin, Mycophil agar with chloromycetin and Actidione, and cornmeal agar with chloromycetin were quantitatively and qualitatively compared for the detection of fungi on spacecraft. Cornmeal agar with chloromycetin yielded the highest number of fungal colonies, although not always significantly higher than Mycophil agar with chloromycetin or TSA spread plates. Cornmeal agar with chloromycetin also gave the best qualitative representation of fungi on the spacecraft, recovering 68% of the genera found from all media. This medium yielded 10 times the number of fungal colonies and 3 times the number of genera found on TSA pour plates as currently used for spacecraft assay.

In vitro susceptibility of isolates of Aspergillus fumigatus and Sporothrix schenckii to amphotericin B.

The in vitro susceptibility of 21 isolates of Aspergillus fumigatus and 12 isolates of Sporothrix schenckii to amphotericin B was determined. The minimal inhibitory concentration (MIC) for the A. fumigatus isolates ranged from 0.14 to 0.6 mug of drug per ml. The mean MIC for the 21 isolates was 0.33 mug per ml. The MIC for the 12 S. schenckii isolates ranged from 0.68 to 2.12 mug of drug per ml, with a mean MIC of 1.38 mug per ml.