The Genome Sequence Of Clostridium Tetani

The genome sequence of Clostridium tetani,
the causative agent of tetanus disease
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Holger Bruggemann*, Sebastian Baumer*, Wolfgang Florian Fricke*, Arnim Wiezer*, Heiko Liesegang*, Iwona Decker*,
Christina Herzberg†, Rosa Martınez-Arias*, Rainer Merkl*, Anke Henne*, and Gerhard Gottschalk*†‡
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*Gottingen Genomics Laboratory and †Department of General Microbiology, Institute ofMicrobiology and Genetics, Georg-August-University,
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Grisebachstrasse 8, D-37077 Gottingen, Germany
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Edited by Dieter Soll, Yale University, New Haven, CT, and approved December 11, 2002 (received for review September 27, 2002)
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Tetanus disease is one of the most dramatic and globally prevalent
diseases of humans and vertebrate animals, and has been reported
for over 24 centuries. Themanifestation of the disease, spastic
paralysis, is caused by the second most poisonous substance
known, the tetanus toxin, with a human lethal dose of 1 ng kg.
Fortunately, this disease is successfully controlled through immunization with tetanus toxoid; nevertheless, according to the World
Health Organization, an estimated 400,000 cases still occur each
year, mainly of neonatal tetanus. Thecausative agent of tetanus
disease is Clostridium tetani, an anaerobic spore-forming bacterium, whose natural habitat is soil, dust, and intestinal tracts of
various animals. Here we report the complete genome sequence of
toxigenic C. tetani E88, a variant of strain Massachusetts. The
genome consists of a 2,799,250-bp chromosome encoding 2,372
ORFs. The tetanus toxin and a collagenase are encoded ona
74,082-bp plasmid, containing 61 ORFs. Additional virulencerelated factors could be identified, such as an array of surfacelayer and adhesion proteins (35 ORFs), some of them unique to C.
tetani. Comparative genomics with the genomes of Clostridium
perfringens, the causative agent of gas gangrene, and Clostridium
acetobutylicum, a nonpathogenic solvent producer, revealed a
remarkablecapacity of C. tetani: The organism can rely on an
extensive sodium ion bioenergetics. Additional candidate genes
involved in the establishment and maintenance of a pathogenic
lifestyle of C. tetani are presented.

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eurotoxigenic clostridia have attracted considerable attention during the past decades. The mode of action of the
strongest toxins known to mankind, the tetanus toxin produced
byClostridium tetani and the homologous botulinum toxins A–G
produced by various Clostridium botulinum strains, is now well
understood (1–4). The tetanus toxin (TeTx) blocks the release
of neurotransmitters from presynaptic membranes of inhibitory
neurons of the spinal cord and the brainstem of mammals; it
catalyzes the proteolytic cleavage of the synaptic vesicle protein
synaptobrevin (5).This leads to continuous muscle contractions,
which are primarily observed in jaw and neck muscles (lockjaw).
Since the introduction of a potent vaccine during World War II,
cases of tetanus disease have been only sporadic in industrial
countries. However, the disease, and in particular neonatal
tetanus (NT), is still an important cause of death due to
insufficient immunization (4, 6). NT isthe second leading cause
of death from vaccine-preventable diseases among children
worldwide. It is considered endemic to 90 developing countries,
with an estimated 248,000 deaths occurring in 1997 (World
Health Organization; www.who.int vaccines-diseases diseases
NeonatalTetanus.shtml).
So far, genetic information on C. tetani is mainly restricted to
the nucleotide sequences of the tetanustoxin TeTx and of its
direct transcriptional activator TetR, both of which are encoded
on a plasmid, designated pCL1 in the strain Massachusetts
(7–10). The identification and analysis of all genes in the genome
of C. tetani will contribute to our understanding of the lifestyle
switch from a harmless soil bacterium to a potentially devastating neurosystem-damaging organism after entering...