Large-scale screening of nasal swabs for Bacillus anthracis: descriptive summary and discussion of the National Institutes of Health's experience.
In October 2001, a letter containing a large number of anthrax spores was sent through the Brentwood post office in Washington, D.C., to a United States Senate office on Capitol Hill, resulting in contamination in both places. Several thousand people who worked at these sites were screened for spore exposure by collecting nasal swab samples. We describe here a screening protocol which we, as a level A laboratory, used on very short notice to process a large number of specimens (3,936 swabs) in order to report preliminary results as quickly as possible. Six isolates from our screening met preliminary criteria for Bacillus anthracis identification and were referred for definitive testing. Although none of the isolates was later confirmed to be B. anthracis, we studied these isolates further to define their biochemical characteristics and 16S rRNA sequences. Four of the six isolates were identified as Bacillus megaterium, one was identified as Bacillus cereus, and one was an unidentifiable Bacillus sp. Our results suggest that large-scale nasal-swab screening for potential exposure to anthrax spores, particularly if not done immediately postexposure, may not be very effective for detecting B. anthracis but may detect a number of Bacillus spp. that are phenotypically very similar to B. anthracis.
Kiratisin
Pattarachai
P
Microbiology Service, Department of Laboratory Medicine, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA. pkiratisin@mail.cc.nih.gov
Fukuda
Caroline D
CD
Wong
Alexandra
A
Stock
Frida
F
Preuss
Jeanne C
JC
Ediger
Laura
L
Brahmbhatt
Trupti N
TN
Fischer
Steven H
SH
Fedorko
Daniel P
DP
Witebsky
Frank G
FG
Gill
Vee J
VJ
D000881:Anthrax / Q000175:diagnosis* / Q000382:microbiology; D001407:Bacillus / Q000145:classification / Q000302:isolation & purification; D001408:Bacillus anthracis / Q000145:classification / Q000302:isolation & purification* / Q000502:physiology; D015373:Bacterial Typing Techniques; D023482:Bioterrorism; D003470:Culture Media; D004219:District of Columbia; D007753:Laboratories; D008403:Mass Screening / Q000379:methods*; D009297:Nasal Mucosa / Q000382:microbiology*; D009316:National Institutes of Health (U.S.); D013048:Specimen Handling; D013171:Spores, Bacterial; D014481:United States
D003470:Culture Media