title: Molecular subtyping of Bacillus anthracis and the 2001 bioterrorism-associated anthrax outbreak, United States.
abstract: Molecular subtyping of Bacillus anthracis played an important role in differentiating and identifying strains during the 2001 bioterrorism-associated outbreak. Because B. anthracis has a low level of genetic variability, only a few subtyping methods, with varying reliability, exist. We initially used multiple-locus variable-number tandem repeat analysis (MLVA) to subtype 135 B. anthracis isolates associated with the outbreak. All isolates were determined to be of genotype 62, the same as the Ames strain used in laboratories. We sequenced the protective antigen gene (pagA) from 42 representative outbreak isolates and determined they all had a pagA sequence indistinguishable from the Ames strain (PA genotype I). MLVA and pagA sequencing were also used on DNA from clinical specimens, making subtyping B. anthracis possible without an isolate. Use of high-resolution molecular subtyping determined that all outbreak isolates were indistinguishable by the methods used and probably originated from a single source. In addition, subtyping rapidly identified laboratory contaminants and nonoutbreak-related isolates.
authors.affiliation: Centers for Desease Control and Prevention , Atlanta, Georgia 30333, USA. amh9@cdc.gov
authors.forename: Alex R
authors.initials: AR
authors.lastname: Hoffmaster
authors.forename: Collette C
authors.initials: CC
authors.lastname: Fitzgerald
authors.forename: Efrain
authors.initials: E
authors.lastname: Ribot
authors.forename: Leonard W
authors.initials: LW
authors.lastname: Mayer
authors.forename: Tanja
authors.initials: T
authors.lastname: Popovic
mesh_terms: D000881:Anthrax / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology*; D001408:Bacillus anthracis / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D015373:Bacterial Typing Techniques / Q000379:methods*; D023482:Bioterrorism; D004196:Disease Outbreaks; D005798:Genes, Bacterial; D005819:Genetic Markers; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D019570:Inhalation Exposure; D016133:Polymerase Chain Reaction; D014481:United States / Q000453:epidemiology
chemical_list: D005819:Genetic Markers