Clostridium

• gram positive
• Anaerobic
• spore forming bacilli
• Some pathogens(C.perfingens,C.tetani)are normally found in human intestines

• causative organusm of tetanus
• widely distributed in soil and intestines of humans and animals

Morphology

• Slender bacillus
• Straight axis,parallel sides and rounded ends
• occurs singly and occasionally in chains
• spores - terminal, spherical and bulging 'drumstick appearance'

Classification

Ten serological types based on agglutinations

Type VI - non-flagellated strains

Others - flagellar antigens

Pathogenicity

• have little invasive power
• Germination and toxin production occur only if favourable conditions exist such as
  • reduced OR potential
  • devitalised tissues
  • foreign bodies
  • concurrent infection
• the toxin produced is  absorbed by the motor endings and transported to the CNS intra-axonally
• the toxin is specifically and avidly fixed by gangliosides of the grey matter(nervous tissue)

Toxins

atleast two distinct toxins

• hemolysin(tetanolysin) It is not relevant in the pathogenesis of tetanus
• neurotoxin(tetanospasmin) this is the toxin resposnsible for tetanus it gets toxoided spontaneously or in the presence of low concentrations of formaldehyde