Correlating bacterial shedding with fecal corticosterone levels and serological responses from layer hens experimentally infected with Salmonella Typhimurium

Sharma, Pardeep; Pande, Vivek; Moyle, Talia S.; McWhorter, Andrea R.; Chousalkar, Kapil K.

doi:10.1186/s13567-017-0414-9

Cited by 15 publications

(13 citation statements)

References 39 publications

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“…Spleen and liver samples from all birds were negative for S. Typhimurium DT9. This result is in contrast to a recent layer hen trial which demonstrated that spleen and liver samples remained positive for S. Typhimurium for 16 weeks post-infection ( Sharma et al, 2017 ). Duplicate ileum, caecal, infundibulum, isthmus, magnum, shell gland and vagina tissue sections were collected and treated with gentamicin to kill any bacteria adhered to the surface.…”

Section: Discussioncontrasting

confidence: 99%

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A Long-Term Efficacy Trial of a Live, Attenuated Salmonella Typhimurium Vaccine in Layer Hens

McWhorter

Chousalkar

2018

Front. Microbiol.

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Salmonella remains one of the most common causes of bacterial foodborne gastrointestinal disease in humans. Raw eggs or food items containing undercooked eggs are frequently identified as the source of Salmonella. Salmonella Typhimurium contamination of table eggs most commonly occurs when they are laid in a contaminated environment. Several control strategies, including vaccination, are widely used to mitigate the total Salmonella load. It is unclear, however, whether live attenuated Salmonella vaccines are efficacious over the life span of a layer hen. Live attenuated Salmonella vaccines have been favored due to their ability to illicit a strong humoral immune response. The lifespan of a layer hen ranges between 60 and 80 weeks and the long term efficacy of attenuated vaccine strains has not been investigated. In this study, commercial brown layer chicks were vaccinated at day old, 6 weeks of age, and again at 10 weeks of age with the Bioproperties VaxsafeTM STM1 aroA mutant vaccine. Birds were challenged at 18 weeks of age with Salmonella Typhimurium DT9 (MLVA 03 15 08 11 550). Feces and eggs were monitored for S. Typhimurium for 40 weeks post-infection. Birds produced a strong immune response following the final dose which was administered intramuscularly. The serum antibody response to S. Typhimurium DT9 infection did not differ between challenged groups. Fecal shedding and egg contamination was highly variable and did not differ significantly between vaccinated and unvaccinated birds that had been challenged with S. Typhimurium DT9. Total bacterial load in feces was quantified using qPCR. No significant difference was detected between unvaccinated and vaccinated birds after challenge.

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Section: Discussioncontrasting

confidence: 99%

“…Negative and positive controls were included in every reaction. A two-step qPCR cycling method was used as per ( Sharma et al, 2017 ). Cycling conditions included an initial melt at 95°C for 5 min followed by 35 cycles of 95°C for 10 s and 58°C 30 s using a Rotor Gene 6000 (Corbett Research, United States).…”

Section: Methodsmentioning

confidence: 99%

A Long-Term Efficacy Trial of a Live, Attenuated Salmonella Typhimurium Vaccine in Layer Hens

McWhorter

Chousalkar

2018

Front. Microbiol.

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“…The use of the live vaccine, probiotic or prebiotic each alone decreased the re-isolation rate of the bacterium, particularly from the spleen and heart, to zero, while a combination of the vaccine with probiotic or prebiotic resulted in zero rates on all investigated organs at the 7th day PC (Figure 3, Table 1). These results indicated that the combination of probiotic or prebiotic with live vaccine was most effective on clearance of SE, as previous studies have shown that Salmonella may persist on internal organs for long periods, such as that which was observed in a layer hen trial by Sharma et al [34], who reported that S. typhimurium was detected on the spleen and liver for 16 weeks post-infection. Moreover, it was thought that Salmonella invades with persistent infection in intestinal cells [35], so the use of prebiotics or probiotics could be used to modulate the gut microflora, and thus limit Salmonella colonization of birds [36,37].…”

Section: Resultssupporting

confidence: 67%

The Simultaneous Administration of a Probiotic or Prebiotic with Live Salmonella Vaccine Improves Growth Performance and Reduces Fecal Shedding of the Bacterium in Salmonella-Challenged Broilers

El‐Shall

Awad

El‐Hack

et al. 2019

Animals

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Salmonellosis is one of the most important bacterial diseases in poultry, causing heavy economic losses, increased mortality and reduced production. The aim of this study was the comparative efficacy of a commercial probiotic and/or prebiotic with a live attenuated Salmonella Enteritidis (SE) vaccine on the protection of broiler chickens from SE challenge. The efficacy of probiotic or prebiotic products, as well as a live Salmonella Enteritidis (SE) vaccine at the 7th day of age, administered via drinking water, were evaluated for clinical protection and effects on growth performance of broiler chickens experimentally challenged with SE at the 28th day of age. The use of probiotic or prebiotic simultaneously with the live Salmonella vaccine can diminish the negative effect of live vaccine growth performance, reducing mortality rate, fecal shedding, and re-isolation of SE from liver, spleen, heart and cecum. The use of probiotic or prebiotic simultaneously with the application of the live Salmonella vaccine is a good practice to diminish the negative effect of the harmful bacteria and improve the growth performance of broilers. Thus, further studies may be carried out with layers and breeders.

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“…This finding was in agreement with a previous trial [ 14 ]. Oral S. Typhimurium challenge with 10 9 CFU bacteria is sufficient to produce a strong antibody response in infected hens [ 15 ]. Oral administration of Vaxsafe® ST does not induce a strong humoral immune response and only transitory reduction in Salmonella colonization of the caeca [ 14 ].…”

Section: Discussionmentioning

confidence: 99%

Shedding of Salmonella Typhimurium in vaccinated and unvaccinated hens during early lay in field conditions: a randomised controlled trial

et al. 2018

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BackgroundSalmonella vaccination is one of the control measure that farmers can use to reduce bacterial shedding in their flocks. This study aimed to examine the efficacy of the Vaxsafe® ST (Strain STM-1) attenuated live vaccine administered as ocular and oral doses followed by an intramuscular (IM) dose in rearing, in reducing contamination by Salmonellae of both eggs and the environment in the commercial multi-age cage layer sheds. A randomised controlled trial was conducted up to 26 weeks post last vaccine on two different multi-age caged egg farms.ResultsNo clinical symptoms were observed following IM administration of STM-1 during rearing. Following the first two STM-1 doses, both vaccinated and unvaccinated birds exhibited antibody titres below the positive cut-off value, however after IM administration of STM-1, antibody titres in the vaccinated group were above the cut-off value. Wild type Salmonella Typhimurium was not detected during the rearing of pullets. During production, the antibody titres were significantly higher in the vaccinated group at all sampling points during this trial. There was no significant difference in the prevalence of Salmonella (detected by culture and PCR method) between the vaccinated and unvaccinated groups on the egg belt and faeces in early lay. Wild-type Salmonella spp. were consistently found in dust samples. Quantitative PCR (qPCR) assay was able to differentiate between the live vaccine strain and wild type Salmonella. The load of wild-type Salmonella in shed environment was relatively low (1.3 log10 ± 0.48 CFU/m2 of surface area).ConclusionGiven that Salmonella Typhimurium and other serovars are able to survive/persist in the shed environment (such as in dust), regular cleaning and or removal of dust from shed is important. Use of the Vaxsafe® ST vaccine in multi-age flocks is “not an ultimate intervention” for reduction of Salmonella Typhimurium because of the complexities involved in achieving control, such as the efficacy of cleaning of sheds, the lack of resting periods between batches and the possible carry over of contamination from existing flocks. Hence implementation of more than one or several interventions strategies is essential.Electronic supplementary materialThe online version of this article (10.1186/s12866-018-1201-0) contains supplementary material, which is available to authorized users.

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Correlating bacterial shedding with fecal corticosterone levels and serological responses from layer hens experimentally infected with Salmonella Typhimurium

Cited by 15 publications

References 39 publications

A Long-Term Efficacy Trial of a Live, Attenuated Salmonella Typhimurium Vaccine in Layer Hens

A Long-Term Efficacy Trial of a Live, Attenuated Salmonella Typhimurium Vaccine in Layer Hens

The Simultaneous Administration of a Probiotic or Prebiotic with Live Salmonella Vaccine Improves Growth Performance and Reduces Fecal Shedding of the Bacterium in Salmonella-Challenged Broilers

Shedding of Salmonella Typhimurium in vaccinated and unvaccinated hens during early lay in field conditions: a randomised controlled trial

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