Salmonella meleagridis
Author: Sushil Tamrakar
General overview of Salmonella and Salmonellosis
Salmonella is a genus of rod-shaped, gram-negative, non-spore forming, predominantly motile enterobacteria (Chalker and Blaser 1988). Many species of Salmonella have been isolated from eggs and egg products (McCullough and Eisele 1951). Salmonella meleagridis is one of the most common serotype of Salmonella (Zaidi, McDermott et al. 2006). Twenty human isolates of S. meleagridis had been identified in Canada so far during 1997.
http://www.cdc.gov/salmonella/
Summary Data
McCullough, and Eisele (1951) inoculated human volunteers orally with the S. Meleagridis strain I,II and III.[1]
| Experiment serial number |
Reference |
Host type |
Agent strain |
Route |
# of doses |
Dose units |
Response |
Best fit model |
Optimized parameter(s) |
LD50/ID50
|
| 238* |
[1] |
human |
strain I |
oral, with eggnog |
11 |
CFU |
infection |
beta-Poisson |
α= 3.89E-01 , N50 = 1.68E+04 |
1.68E+04
|
| 240 |
[1] |
human |
strain III |
oral, with eggnog |
4 |
CFU |
infection |
beta-Poisson |
α = 8.85E-01 , N50 = 5.24E+05 |
5.24E+05
|
| *This model is preferred in most circumstances. However, consider all available models to decide which one is most appropriate for your analysis.
|
|
*Recommended Model
Eexperiment number 238 is the recommended one as the strain I was more virulent than strain III.
Optimization Output for experiment 238 (Salmonella meleagridis)
Human / S. meleagridis strain I data [1]
| Dose |
Infected |
Non-infected |
Total
|
| 12000 |
3 |
3 |
6
|
| 24000 |
4 |
2 |
6
|
| 52000 |
3 |
3 |
6
|
| 96000 |
3 |
3 |
6
|
| 155000 |
5 |
1 |
6
|
| 3E+05 |
6 |
0 |
6
|
| 720000 |
4 |
1 |
5
|
| 1150000 |
6 |
0 |
6
|
| 5.5E+06 |
5 |
1 |
6
|
| 2.4E+07 |
5 |
0 |
5
|
| 5E+07 |
6 |
0 |
6
|
|
Goodness of fit and model selection
| Model |
Deviance |
Δ |
Degrees
of freedom |
χ20.95,1
p-value |
χ20.95,m-k
p-value
|
| Exponential
|
71.8
|
63.8
|
10
|
3.84
1.33e-15
|
18.3
1.98e-11
|
| Beta Poisson
|
7.99
|
9
|
16.9
0.535
|
| Beta-Poisson fits better than exponential; cannot reject good fit for beta-Poisson.
|
|
Optimized parameters for the beta-Poisson model, from 10000 bootstrap iterations
| Parameter
|
MLE estimate
|
Percentiles
|
| 0.5% |
2.5% |
5% |
95% |
97.5% |
99.5%
|
| α
|
3.89E-01
|
1.23E-01 |
1.74E-01 |
2.01E-01 |
1.12E+00 |
1.91E+00 |
3.82E+02
|
| N50
|
1.68E+04
|
7.98E+01 |
1.08E+03 |
2.27E+03 |
4.78E+04 |
5.71E+04 |
7.49E+04
|
|
Parameter scatter plot for beta Poisson model ellipses signify the 0.9, 0.95 and 0.99 confidence of the parameters. 
beta Poisson model plot, with confidence bounds around optimized model
Optimization Output for experiment 240 (Salmonella meleagridis)
Human/ S. meleagridis strain III data [1]
| Dose |
Infected |
Non-infected |
Total
|
| 158000 |
1 |
5 |
6
|
| 1.5E+06 |
5 |
1 |
6
|
| 7680000 |
6 |
0 |
6
|
| 1E+07 |
5 |
1 |
6
|
|
Goodness of fit and model selection
| Model |
Deviance |
Δ |
Degrees
of freedom |
χ20.95,1
p-value |
χ20.95,m-k
p-value
|
| Exponential
|
7.81
|
5.51
|
3
|
3.84
0.019
|
7.81
0.0501
|
| Beta Poisson
|
2.3
|
2
|
5.99
0.316
|
| Beta-Poisson fits better than exponential; cannot reject good fit for beta-Poisson.
|
|
Optimized parameters for the beta-Poisson model, from 10000 bootstrap iterations
| Parameter
|
MLE estimate
|
Percentiles
|
| 0.5% |
2.5% |
5% |
95% |
97.5% |
99.5%
|
| α
|
8.85E-01
|
1.78E-01 |
2.91E-01 |
3.68E-01 |
1.40E+03 |
1.71E+03 |
8.24E+03
|
| N50
|
5.24E+05
|
4.71E+04 |
1.20E+05 |
1.92E+05 |
1.19E+06 |
1.39E+06 |
1.90E+06
|
|
Parameter scatter plot for beta Poisson model ellipses signify the 0.9, 0.95 and 0.99 confidence of the parameters. 
beta Poisson model plot, with confidence bounds around optimized model
References
- ↑ 1.0 1.1 1.2 1.3 1.4 McCullough NB, Eisele CW (1951) Experimental human salmonellosis. II. Immunity studies following experimental illness with Salmonella meleagridis and Salmonella anatum. Journal of immunology (Baltimore, Md. : 1950) 66(5): 595-608.
Chalker RB and Blaser MJ (1988) A Review of Human Salmonellosis: III. Magnitude of Salmonella Infection in the United States. Reviews of Infectious Diseases 10(1), 111-124.
McCullough NB and Eisele CW (1951) Experimental Human Salmonellosis: II. Immunity Studies Following Experimental Illness with Salmonella Meleagridis and Salmonella Anatum. The Journal of Immunology 66(5), 595-608.
McCullough NB and Eisele CW (1951) Experimental Human Salmonellosis: III. Pathogenicity of Strains of Salmonella newport, Salmonella derby, and Salmonella bareilly Obtained from Spray-Dried Whole Egg. The Journal of Infectious Diseases 89(3), 209-213.
Zaidi MB, McDermott PF, Fedorka-Cray P, Leon V, Canche C, Hubert SK, Abbott J, León M, Zhao S, Headrick M and Tollefson L (2006) Nontyphoidal Salmonella from Human Clinical Cases, Asymptomatic Children, and Raw Retail Meats in Yucatan, Mexico. Clinical Infectious Diseases 42(1), 21-28.
