engleski

Virulence of different Legionella species in A/J mice.

Legionellae are environmental organisms that can cause disease in humans. The clinical manifestation of legionella infection range from the flu like symptoms to potentally fatal pneumonia and multisystem disease. Legionella pneumophila is the predominant cause of Legionnaires’ disease in the United States and Europe in contrast to L. longbeachae which is the leading cause of the legionelosis in Australia. L. micdadei cause disease in immunocompromised people while L. steigerwaltii is not pathogen to humans. To determine the differences in virulence of those four legionella strains, A/J mice were intratracheally inoculated. At different time points after infection (2, 24, 48 and 72 hours) mice were sacrificed, and the lungs were removed and proceed for determination of cfu (colony forming units). Our results showed the dramatic difference in mortality rate in A/J mice between those four strains. For L. longbeachae LD 50 was 104 cfu in comparison to L. pnemophila infection with LD 50 of 108 cfu. For L. micdadei LD 50 was 108 cfu while all mice infected with L. steigerwaltii survived infection. We conclude that L. longbeachae serogroup 1 causes a more severe infection in A/J mice compared to other legionella strains.

legionella; animal model; lungs

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