agar and Anthrax

Anthrax Blood Agar (ABA) and Cereus Ident Agar (CEI) were evaluated as selective growth media for the isolation of Bacillus anthracis using 92 B. anthracis and 132 other Bacillus strains from 30 species. The positive predictive values for the identification of B. anthracis on ABA, CEI, and the combination of both were 72%, 71%, and 90%, respectively. Thus, less than 10% of all species were misidentified using both nutrient media. Species which might be misidentified as B. anthracis were B. cereus, B. mycoides, and B. thuringiensis. Particularly, 30% of B. weihenstephanensis strains were misidentified as B. anthracis.

Topics: Agar; Anthrax; Bacillus anthracis; Bacteriological Techniques; Culture Media; Humans

During the anthrax attack of 2001, the Florida Department of Health (FDOH) Bureau of Laboratories in Tampa received hundreds of isolates suspected of being Bacillus anthracis. None were confirmed to be B. anthracis since most isolates were motile and not even in the Bacillus cereus group. Although the sentinel laboratories now send fewer isolates to FDOH laboratories, should another attack occur the number of isolates submitted would likely increase dramatically, and this upsurge would seriously challenge personnel who are expected to be busy examining an increased number of environmental samples. We examined two selective and differential growth media and alternative motility methods that could be used to streamline the processing of suspicious isolates. Of 60 isolates previously sent to the FDOH laboratory, 56 were endospore-forming gram-positive rods and only 7 grew on mannitol-egg yolk-polymyxin B agar and/or the Anthracis chromogenic agar. Microscopic observation of early-log-phase growth (2 to 3 h) in a shaking broth was the best method to detect motility in 40 isolates that appeared nonmotile in the motility media investigated. One of these growth media and microscopic examination of shaken broth cultures can be used to show that an isolate is not B. anthracis before expensive molecular and antibody-based tests are performed. By doing so, costs could be reduced and analysis time shortened.

Topics: Agar; Anthrax; Bacillus; Bacillus anthracis; Bacteriological Techniques; Bioterrorism; Culture Media; Hemolysis; Humans; Movement

Topics: Agar; Animals; Anthrax; Bacillus anthracis; Bacteriological Techniques; Bacteriology; Cattle; Cholera; Cricetinae; Germany; Guinea Pigs; History, 19th Century; Humans; Lung; Mycobacterium tuberculosis; Spores, Bacterial; Tuberculosis, Pulmonary; Vibrio cholerae

A modification of the agar-gel precipitation inhibition technique of Thorne and Belton for detecting anthrax antibodies reduces inconsistency of visually determined end points on the same sera observed by different technicians. Determination of the minimal reacting concentrations of the anthrax antigen and antibody reagents, modifications of the visualization apparatus, methods for combining reagents, and length of incubation periods contribute to the ease of the end-point determinations and the uniformity of results. When compared with the previous technique, the modified procedure is less time-consuming while retaining satisfactory reproducibility, simplicity, specificity, and sensitivity.

Topics: Agar; Anthrax; Antibodies; Bacillus anthracis; Culture Media; Immune Sera; Immunodiffusion; Precipitin Tests; Precipitins; Reproducibility of Results; Research

Topics: Acridines; Agar; Anthrax; Bacillus anthracis; Fasting; Virulence

Topics: Acridines; Agar; Anthrax; Bacillus anthracis; Fasting