A comparison of aerosol and intragastric routes of infection withListeriaspp

Abstract

SUMMARYAerosol infection (Al) of Porton outbred mice with Listeria species, exhibiting varying degrees of virulence, was compared with gastric intubation (GI) on the basis of numbers of deaths, 50% lethal dose (LD50) and pattern of listerial infection. The Al route appeared to be more sensitive, efficient and consistent than GI in that it required 105 fewer micro-organisms to obtain infection and death then ensued within 4 days, with GI deaths usually occurring on day 7. All the virulent strains tested caused 100 % mortality by AI, while virulent and avirulent strains were indistinguishable by GI. Bacterial counts in the livers and spleens of infected mice were consistent with the relative virulence of the infectious agent using AI but not in GI mice. There were higher numbers of micro-organisms and more widespread lesions in the organs of AI mice than in GI. Results indicate that Al is an accurate in vivo indicator of virulence in listeria and using Al, bacterial counts in the liver and spleen could replace LD50 tests, thereby reducing the number of animals required for in vivo virulence testing.

Cross-infection of chicks by airborne transmission of Salmonella enteritidis PT4

“…typhimurium are required to produce disease in mice when given as an aerosol (Wathes et al 1988). It has also been reported that aerosol infection of mice with selected species of listeria required 10' fewer organisms (than the oral route) to produce infection (Bracegirdle et al 1994). Given the low levels of airborne salmonella in this experiment, chicks are clearly more susceptible to salmonella infection by the aerosol route than mice.…”

Listeria monocytogenes in spontaneous abortions in humans and its detection by multiplex PCR

“…Listeria monocytogenes has been found in 10% or more of normal healthy people, usually in the gut (Anon 2005). All the 13 serovars of L. monocytogenes are reported to cause human listeriosis, but serovars 1/2a, 1/2b and 4b are implicated with most of the cases (Bracegirdle et al. 1994).…”

Probiotic Potential of Indian Traditional Fermented Foods to Combat Listeriosis

“…Contrary to typical foodborne pathogens like Salmonella spp., which seldom result in fatalities, listeriosis is now known to have a staggering fatality rate of up to 30% [78]. The common serotypes linked to human listeriosis include 1/2a, 1/2b, and 4b [80]. Since the placenta acts as a breeding ground for LM, pregnant women are more susceptible to infection.…”