الفهرس | Only 14 pages are availabe for public view |
Abstract Listeria monocytogenes (L. monocytogenes) is a Gram-positive, facultatively anaerobic, rod-shaped intracellular bacterium that causes listeriosis, affecting both animals and humans. The bacterium is ubiquitous in the environment, and its natural habitat is thought to be decomposing plant material, in which it lives as a saprophyte and can multiply when temperature and humidity are optimal. L. monocytogenes infection has been described in a wide range of animal species, but farm animals are the most commonly affected. After ingestion, L. monocytogenes is able to penetrate the mucosa of the intestine and cause infections in humans and animals, which can include septicaemia, meningitis, encephalitis or uterine infections. The incidence rate of sublinical mastitis caused by L. monocytogenes seems to be lower in comparison with other mastitis pathogens, like Klebsiella, EscherichiaShigella, Streptococcus or Corynebacterium, but its prevalence in farms is high. Some animals can be latent L. monocytogenes carriers without showing any signs of disease. In those apparently healthy animals, the bacterium is frequently found in faeces and in nasal and genital secretions, acting as vectors of infection for the herd |