Clostridium tetani

Synonyms:

tetanus bacillus

Classification:

anaerobic, gram+ bacteria, sporulating rods

Diseases

Sites and Sources

Diagnostic Factors

Virulence Factors

Treatment and Prevention

Commentary

Tetanus is a toxigenic infection of anaerobic tissue. Under anaerobic conditions the spores germinate and the organism produces a powerful neurotoxin that prevents release of the inhibitory neurotransmitter in the spinal cord. This causes opposing pairs of muscles to contract, leading to spastic paralysis. Typically there is a deep puncture wound that becomes contaminated with the tetanus spores that are common inhabitants of soil. Prevention is by immunization of infants with DPT and of adults every 10 years with Td, toxoids of tetanus and diphtheria. Infants normally receive antibody from their mothers transplacentally so are protected at birth. If the mothers are not vaccinated, however, neonatal tetanus can occur. It is usually associated with nonsterile delivery and/or improper umbilical cord care practices. In countries where tetanus vaccination is not common, neonatal tetanus takes a large toll, with some 277,400 deaths/year. Neonatal tetanus is very rare in the US but in 1998 there was a case in Montana traced to the use of non-sterile clay used to pack the umbilical wound. The CDC (Nov 6, 1998 MMWR) reported the case as follows: "On March 21, a 9-day old newborn, who had no previous medical problems, was taken to a hospital by her parents who reported a 10-hour history of an inability to nurse and difficulty opening her jaw. Her parents also had noticed a foul-smelling discharge from her umbilical cord. On admission, the newborn had trismus (lockjaw), increased general muscle tone, and hyperresponsiveness to external stimuli. The cord was covered with dried clay, which when retracted revealed a foul smelling yellow-green discharge. Culture from the umbilical cord grew several anaerobes and aerobic bacterial species. The baby was treated with tetanus immune globulin and penicillin G for 10 days. On March 24, she required mechanical ventilation for 12 days. She was discharged on April 10 with no apparent neurologic sequelae and was developing normally on follow-up at 7 months." The mother had never been vaccinated because of her family's philosophical beliefs. A midwife had provided the health and beauty clay to accelerate drying of the cord. Vaccination with tetanus toxoid is safe and effective during pregnancy and could have prevented this near tragedy. Td is recommended for pregnant women who have not been vaccinated during the previous 10 years.