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Dermonecrotic toxin production by strains of Pasteurella multocida isolated from man
P Y Donnio1, J L Avril, P M Andre
1Laboratoire de Bactériologie et Virologie, Hôpital Pontchaillou, Rennes, France.
Abstract:
Ninety-four clinical isolates of Pasteurella multocida of human origin were tested for dermonecrotic toxin (DNT) production by three methods: dermonecrotic test in guinea-pigs, Vero cell culture cytotoxicity and ELISA. The strains were isolated from patients living in a rural area with widespread intensive pig breeding. Six strains were found to be toxigenic by the three tests. A major protein band of Mr 145 Kda corresponding to DNT on immunoblots was demonstrated in extracts from these strains. All were isolated from respiratory tract (diseases 5, healthy carriage 1). The difference between isolates from the respiratory tract and isolates from wounds inflicted by pets was statistically significant with regard to DNT production (p less than 0.02). A possible role of the toxin in pulmonary diseases caused by P. multocida has yet to be established.
Insights
Six Pasteurella multocida strains produced dermonecrotic toxin (DNT), detected by guinea-pig tests, cell cultures, and ELISA. DNT production was significantly higher in respiratory isolates compared to wound isolates.
Area of Science:
- Microbiology
- Bacteriology
- Toxicology
Background:
- Pasteurella multocida is a bacterium that can cause various infections in humans and animals.
- Dermonecrotic toxin (DNT) is a virulence factor produced by some strains of P. multocida.
- Human isolates of P. multocida are often associated with animal contact, particularly pigs and pets.
Purpose of the Study:
- To investigate the production of dermonecrotic toxin (DNT) in clinical isolates of Pasteurella multocida from human sources.
- To compare DNT production between isolates from different anatomical sites, specifically the respiratory tract and wounds.
- To identify the molecular characteristics of DNT in toxigenic strains.
Main Methods:
- Ninety-four human clinical isolates of P. multocida were tested for DNT production.
- Three methods were employed: a dermonecrotic test in guinea pigs, Vero cell culture cytotoxicity assay, and Enzyme-Linked Immunosorbent Assay (ELISA).
- Immunoblotting was used to identify protein bands corresponding to DNT.
Main Results:
- Six out of 94 isolates were confirmed as toxigenic for DNT using all three detection methods.
- A major protein band of approximately 145 kDa, consistent with DNT, was identified in toxigenic strains.
- Isolates from the respiratory tract showed a statistically significant higher rate of DNT production compared to isolates from pet-inflicted wounds (p < 0.02).
Conclusions:
- A subset of human P. multocida isolates, particularly those from the respiratory tract, possess the capability to produce dermonecrotic toxin.
- The findings suggest a potential role for DNT in respiratory tract infections caused by P. multocida, although further research is needed.
- The study highlights the importance of considering toxigenicity when characterizing P. multocida isolates from human infections.