Low Persistence of a Large-Plasmid-Cured Variant of Salmonella enteritidis in Ceca of Chicks

Abstract

In order to estimate the contribution of Salmonella in the persistence of this bacterium in chicks, we compared the persistence of a Salmonella enteritidis strain and its plasmid-cured variant in a chicken asymptomatic carrier state model. After oral inoculation, colonization with the plasmid-cured strain was significantly reduced (P < 0.001) in the ceca of chicks from the third week postinoculation and persisted for a shorter period than the wild-type strain. Moreover, numbers of S. enteriditis-infected livers were also significantly lower (P < 0.01) for the plasmid-cured strain compared with the wild-type strain from the third to the seventh week postinoculation. No difference in spleen colonization was observed. These results did not correlate with any in vitro difference in attachment, entry to, or intracellular multiplication of bacteria within intestinal or macrophage avian cell lines.

Role of systemic infection, cross contaminations and super‐shedders in Salmonella carrier state in chicken

“…C); then Salmonella was not detected in spleen 3 to 4 weeks postinfection (pi) even though a few bacteria could still be detected in this organ from weeks 4 to 6 pi in a few animals as previously described (Berthelot‐Hérault et al ., ). This has been also described for liver (Virlogeux‐Payant et al ., ). In contrast to the short‐term infection of the spleens, S .…”

“…However, the mouse models do not seem to be representative of the carrier state observed in chicken and pigs where no persistent systemic infection occurs. In these farm animals, systemic infection precedes persistence in caeca and disappears from spleen and liver, a few weeks after infection (Virlogeux-Payant et al, 2003). A previous study has shown that an intravenous inoculation of Salmonella can lead to caecal persistence (Girard Santosuosso et al, 1998), it is, therefore, important to determine whether systemic infection is required to induce Salmonella carrier state in caeca and/or it determines the development of the carrier state.…”

A large panel of chicken cells are invaded in vivo by Salmonella Typhimurium even when depleted of all known invasion factors

“…the spleen, liver and gall bladder; figure 1 ). The vessels were chosen because Salmonella is able to spread through the body via the blood, and the spleen and liver as they are colonized by Salmonella in chicks [ 37 , 38 ]. Finally, we decided to study the gall bladder as well because Gonzalez-Excobedo & Gunn [ 39 ] demonstrated that the gallbladder epithelium contributed to establishing and maintaining chronic carriage in mice.…”

Infection dynamics of Salmonella Infantis strains displaying different genetic backgrounds – with or without pESI-like plasmid – vary considerably

“…Heidelberg in layer chickens [ 44 ], or for a large-plasmid-cured variant of S . Enteritidis [ 46 ]. In the present study, it can be suspected that multiplication of the pESI– strain in the caeca was less effective which resulted in a lower excretion rate of positive birds being under the detection limit of direct plating.…”

“…As these features were identical in the actual study the shedding patterns can clearly be attributed to the different nature of the used S. Infantis strains. An explanation for this might be the fact that different clones of one Salmonella species are able to adapt differently to the chicken intestine as shown for S. Heidelberg in layer chickens (46), or for a large-plasmid-cured variant of S. Enteritidis (48). In the present study it can be suspected that multiplication of the pESI-strain in the caeca was less effective which resulted in a lower excretion rate of positive birds being under the detection limit of direct plating.…”