Listeria ivanovii is a Gram-positive bacterium primarily linked to infections in animals, especially ruminants. Unlike Listeria monocytogenes, which is a recognized zoonotic pathogen, L. ivanovii often goes unnoticed despite its association with adverse reproductive outcomes such as abortion and stillbirth in sheep, goats, and cattle. This review examines the taxonomy, microbiology, virulence factors, host adaptation, and epidemiology of L. ivanovii, as well as issues related to diagnosis and antimicrobial susceptibility in veterinary practice.
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Current evidence indicates that infections from L. ivanovii are sporadic, with some cases leading to abortion in small ruminant flocks. However, large-scale outbreaks have not been reported. Human infections are rare and generally occur in immunocompromised individuals, implying limited zoonotic potential under normal conditions. Routine laboratory tests often do not distinguish between Listeria species, which may lead to underreporting of L. ivanovii infections.
L. ivanovii, first described as a distinct species in 1984, is currently categorized into two subspecies: L. ivanovii subsp. ivanovii, commonly linked to animal infections, and L. ivanovii subsp. londoniensis, which is less frequently reported. Its preferred hosts include domestic livestock such as sheep, goats, and cattle, where it has been documented to cause reproductive disorders and systemic infections, particularly in young animals.
Typical diagnostic methods may identify Listeria only at the genus level. More precise identification techniques such as PCR, whole-genome sequencing, and mass spectrometry can improve detection rates but are not universally applied. Furthermore, there is a growing understanding of L. ivanovii’s unique virulence mechanisms, which comprise factors like ivanolin O and sphingomyelinase C (SmcL), contributing to its pathogenicity primarily in animal hosts.
In terms of transmission, L. ivanovii is mainly spread through fecal contamination of the environment, with potential reservoirs in animal housing and feed. Although clinical reports appear across various regions, outbreaks are typically limited in scope and do not present comparable public health threats as seen with L. monocytogenes.
Effective control strategies in animal husbandry focus on biosecurity measures, reproductive health management, and environmental hygiene. Although no specific vaccines exist for L. ivanovii, proper management of animal welfare can mitigate its risk. The lack of comprehensive surveillance programs for L. ivanovii in livestock populations further emphasizes the need for enhanced diagnostic practices to better understand its epidemiological impact.