Kingdom Bacteria Order Bacillales Genus Listeria Higher classification Listeria | Division Firmicutes Family Listeriaceae Scientific name Listeria ivanovii Rank Species | |
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Similar Listeria, Bacteria, Listeria innocua, Rhodococcus equi, Listeriaceae | ||
Listeria ivanovii is a species of bacteria in the genus Listeria. The listeria are rod-shaped bacteria and become positively stained when subjected to Gram staining. Of the six bacteria species within the genus, L. ivanovii is one of the two pathogenic species (the other being L. monocytogenes). It behaves like Listeria monocytogenes, but is found almost exclusively in ruminants (mainly sheep). The species is named in honor of Bulgarian microbiologist Ivan Ivanov.
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Distinction
L. ivanovii can be distinguished from L. monocytogenes and other Listeria species by culturing it on sheep or horse blood agar, which will produce a wide, clear or double zone of haemolysis, producing a so-called positive Christie-Atkins-Munch-Petersen (CAMP) reaction with Rhodococcus equi but not with haemolytic Staphylococcus aureus.
Pathology
Infection with L. ivanovii can lead to septicemic disease with enteritis, neonatal sepsis and even abortion. Pregnant ruminants are therefore most at risk.
Human infection
In January 2007, a 55-year-old man was hospitalized in Paris, France. After examination he was thought to have listeriosis. Both blood and stool samples were taken. L. ivanovii was identified, thus characterizing the species as an enteric opportunistic human pathogen. As L. ivanovii is usually only found in ruminants and human infection is extremely rare, this infection can be seen as a form of zoonosis.
Treatment
If diagnosed early, antibiotics can be effective. Antibiotics effective against Listeria species include ampicillin, vancomycin, ciprofloxacin and azithromycin. Early diagnosis is uncommon because infection is not usually accompanied by symptoms.