A two-component direct fluorescent-antibody assay for rapid identification of Bacillus anthracis.
A two-component direct fluorescent-antibody (DFA) assay, using fluorescein-labeled monoclonal antibodies specific to the Bacillus anthracis cell wall (CW-DFA) and capsule (CAP-DFA) antigens, was evaluated and validated for rapid identification of B. anthracis. We analyzed 230 B. anthracis isolates; 228 and 229 were positive by CW-DFA and CAP-DFA assays, respectively. We also tested 56 non-B. anthracis strains; 10 B. cereus and 2 B. thuringiensis were positive by the CW-DFA assay, and 1 B. megaterium strain was positive by CAP-DFA. Analysis of the combined DFA results identified 227 of 230 B. anthracis isolates; all 56 strains of the other Bacillus spp. were negative. Both DFA assays tested positive on 14 of 26 aging clinical specimens from the 2001 anthrax outbreak investigation. The two-component DFA assay is a sensitive, specific, and rapid confirmatory test for B. anthracis in cultures and may be useful directly on clinical specimens.
De
Barun K
BK
Centers for Desease Control and Prevention , Atlanta, Georgia 30333, USA. bkd1@cdc.gov
Bragg
Sandra L
SL
Sanden
Gary N
GN
Wilson
Kathy E
KE
Diem
Lois A
LA
Marston
Chung K
CK
Hoffmaster
Alex R
AR
Barnett
Gwen A
GA
Weyant
Robbin S
RS
Abshire
Teresa G
TG
Ezzell
John W
JW
Popovic
Tanja
T
D000818:Animals; D000881:Anthrax / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D001408:Bacillus anthracis / Q000145:classification / Q000276:immunology / Q000302:isolation & purification*; D016667:Bacterial Capsules / Q000276:immunology; D002417:Cattle; D002473:Cell Wall / Q000276:immunology; D004784:Environmental Monitoring; D005455:Fluorescent Antibody Technique / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial