Francisella tularensis contains several highly pathogenic subspecies, including Francisella tularensis subsp. holarctica, whose distribution is circumpolar in the northern hemisphere. The phylogeography of these subspecies and their subclades was examined using whole-genome single nucleotide polymorphism (SNP) analysis, high-density microarray SNP genotyping, and real-time-PCR-based canonical SNP (canSNP) assays. Almost 30,000 SNPs were identified among 13 whole genomes for phylogenetic analysis. We selected 1,655 SNPs to genotype 95 isolates on a high-density microarray platform. Finally, 23 clade-and subclade-specific canSNPs were identified and used to genotype 496 isolates to establish global geographic genetic patterns. We confirm previous findings concerning the four subspecies and two Francisella tularensis subsp. tularensis subpopulations and identify additional structure within these groups. We identify 11 subclades within F. tularensis subsp. holarctica, including a new, genetically distinct subclade that appears intermediate between Japanese F. tularensis subsp. holarctica isolates and the common F. tularensis subsp. holarctica isolates associated with the radiation event (the B radiation) wherein this subspecies spread throughout the northern hemisphere. Phylogenetic analyses suggest a North American origin for this B-radiation clade and multiple dispersal events between North America and Eurasia. These findings indicate a complex transmission history for F. tularensis subsp. holarctica.

Background: The genome of Bacillus anthracis, the etiological agent of anthrax, is highly monomorphic which makes differentiation between strains difficult. A Multiple Locus Variable-number tandem repeats (VNTR) Analysis (MLVA) assay based on 20 markers was previously described. It has considerable discrimination power, reproducibility, and low cost, especially since the markers proposed can be typed by agarose-gel electrophoresis. However in an emergency situation, faster genotyping and access to representative databases is necessary.

Ninety-six isolates of Bacillus anthracis recovered in France between 1994 and 2000 were tested for their susceptibilities to 25 different antibiotics. Resistance to penicillin G and amoxicillin was 11.5%. All of the isolates were resistant to cotrimoxazole and susceptible to doxycycline, ciprofloxacin, pefloxacin, levofloxacin, teicoplanin, vancomycin, clindamycin, imipenem, and rifampin.Bacillus anthracis is an aerobic rod-shaped organism that is the causative agent for anthrax. Humans can be infected after contact with infected animals or their waste products. When anthrax affects humans, it is usually from an occupational exposure, and the cutaneous form represents the majority of cases (95%) (6). Infections usually respond well to prompt antibiotic treatment. The intestinal form is rare and follows the ingestion of food contaminated by spores (14). This form is characterized by an acute inflammation of the intestinal tract, and initial symptoms include nausea, vomiting, and fever. These symptoms are followed by abdominal pain, vomiting of blood, and severe diarrhea. Intestinal anthrax results in death in 25 to 60% of cases. The respiratory form follows the inhalation of spores and is characterized by an abrupt clinical onset with mild fever and malaise. The first stage of infection, lasting from hours to a few days, involves flu-like symptoms including fever, coughing, weakness, and chest pain. The second stage of inhalation infection usually ends in death within a period of days (1, 13). Despite their gravity, both intestinal and respiratory infections can be treated by early intravenous administration of antibiotics and intensive supportive care. Without immediate treatment, inhalation anthrax is usually fatal.Recent events have demonstrated that the major threat of B. anthracis is connected to bioterrorism and biological warfare. Spores produced in dry form can be spread by means of letters or aerosols (2). As all incidents must be treated as real until proven otherwise, there is a necessity for a rapid and effective antibiotic prophylaxis. Doxycycline and ciprofloxacin are effective antibiotic choices for treatment; however, resistance to these antibiotics has been previously described (4, 10). Moreover, the inappropriate use of these drugs may result in the emergence of antibiotic-resistant strains in naturally acquired disease.The aim of this study was to determine the in vitro susceptibilities of 96 isolates of B. anthracis recovered in France to 25 different antibiotics in order to expand the choices for effective antibiotic treatment. One strain was isolated from a human source, 28 were isolated from animal sources, and 67 were isolated from environmental sources. Phenotypic identification was done by a routine laboratory technique: Gram staining, motility, and hemolysis on blood agar. Biochemical identification was performed by using the Biolog (Hayward, Calif.) system with the dangerous pathogens database. Genotypic characterization was performed by using PCR analysis to detect virulence factor g...

V . R AM I SS E, G . P AT R A, J. V AI SS A IR E A N D M . M O CK . 1999. Plasmid genes that are responsible for virulence of Bacillus anthracis are important targets for the DNA-based detection of anthrax. We evaluated the distribution of the Ba813 chromosomal DNA sequence (Ba813) within closely related Bacillus species. Ba813 was systematically identified from 47 strains or isolates of B. anthracis tested, thus indicating its reliability as a tracer for that species. From the 60 strains of closely related Bacillus spp. examined, three bona fide B. cereus and one bona fide B. thuringiensis were found to harbour Ba813. This marker was also detected in Bacillus sp. isolates that were present at high levels in soil samples collected in a place where an anthrax outbreak had occurred. The significance and the possible function of the Ba813 locus is discussed.

While outbreaks of animal anthrax zoonoses still regularly occur in France, little is known about the epidemiology links between them. We have used the eight-locus multilocus variable-number tandem repeat analysis typing technique against a collection of 50 Bacillus anthracis isolates from France. There were eight distinct genotypes belonging to two dissimilar genetic clusters. Regional strain patterns were observed, with the B2 genotypes prevalent in southern France and the A1a genotypes found only in northern France.