Salmonella nontyphoid
Author: Yin Huang
General overview of Salmonella and Salmonellosis
Salmonella, a genus of rod-shaped, gram-negative, non-spore forming, predominantly motile enterobacteria, causes more than 104 cases of infections per year in United States. (Chalker and Blaser 1988). Non-typhoidal salmonellae are important causes of many foodborne infections. Approximately 45,000 cases and 600 deaths have been reported annually to the Centers for Disease Control in the past decade. Salmonellae have a wide range of hosts and are strongly associated with agricultural products (Acheson and Hohmann 2001).
http://wwwnc.cdc.gov/eid/article/10/1/pdfs/03-0171.pdf
Summary Data
Meynell G.G. and Meynell E.W. (1958) inoculated albino (PGMS) mice intraperitoneally with the Salmonella typhimurium strains 216 and 219 and challenged albino (Tuck) mice with Salmonella typhimurium strain 533 via the intraperitoneal route. [1]
| Experiment serial number |
Reference |
Host type |
Agent strain |
Route |
# of doses |
Dose units |
Response |
Best fit model |
Optimized parameter(s) |
LD50/ID50
|
| 246* |
[1] |
mice |
strain 216 and 219 |
intraperitoneal |
10 |
CFU |
death |
beta-Poisson |
α= 2.1E-01 , N50 = 4.98E+01 |
4.98E+01
|
| 247 |
[1] |
mice |
strain 533 |
intraperitoneal |
11 |
CFU |
death |
beta-Poisson |
α = 6.21E-02 , N50 = 3.46E+07 |
3.46E+07
|
| 248 |
[1] |
mice |
strain 533 |
intraperitoneal |
7 |
CFU |
death |
beta-Poisson |
α= 1.08E-01 , N50 = 9.66E+06 |
9.66E+06
|
| *This model is preferred in most circumstances. However, consider all available models to decide which one is most appropriate for your analysis.
|
|
*Recommended Model
Experiment number 246 is recommended model based on the least LD50 value. Although the strains were different and so the virulences, the estimated risk should be in conservative side.
Optimization Output for experiment 246 (Salmonella Typhimurium)
Mice/Salmonella strain 216 and 219 data [1]
| Dose |
Dead |
Survived |
Total
|
| 5 |
7 |
8 |
15
|
| 25 |
4 |
11 |
15
|
| 125 |
7 |
8 |
15
|
| 630 |
9 |
6 |
15
|
| 3160 |
8 |
7 |
15
|
| 16000 |
13 |
2 |
15
|
| 8E+04 |
15 |
0 |
15
|
| 4E+05 |
15 |
0 |
15
|
| 2E+06 |
15 |
0 |
15
|
| 1E+07 |
15 |
0 |
15
|
|
Goodness of fit and model selection
| Model |
Deviance |
Δ |
Degrees
of freedom |
χ20.95,1
p-value |
χ20.95,m-k
p-value
|
| Exponential
|
133
|
113
|
9
|
3.84
0
|
16.9
0
|
| Beta Poisson
|
20.5
|
8
|
15.5
0.00846
|
| Neither the exponential nor beta-Poisson fits well; beta-Poisson is less bad.
|
|
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
|
2.1E-01
|
1.45E-01 |
1.58E-01 |
1.65E-01 |
2.92E-01 |
3.14E-01 |
3.63E-01
|
| N50
|
4.98E+01
|
8.10E+00 |
1.40E+01 |
1.72E+01 |
1.31E+02 |
1.62E+02 |
2.34E+02
|
|
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 247 (Salmonella Typhimurium)
Mice/ Salmonella strain 533 data [1]
| Dose |
Dead |
Survived |
Total
|
| 603 |
6 |
36 |
42
|
| 1910 |
3 |
39 |
42
|
| 6030 |
7 |
35 |
42
|
| 19100 |
5 |
42 |
47
|
| 60300 |
6 |
34 |
40
|
| 191000 |
3 |
29 |
32
|
| 603000 |
6 |
20 |
26
|
| 1910000 |
7 |
7 |
14
|
| 6030000 |
7 |
5 |
12
|
| 1.91E+07 |
10 |
2 |
12
|
| 6.03E+07 |
13 |
0 |
13
|
|
Goodness of fit and model selection
| Model |
Deviance |
Δ |
Degrees
of freedom |
χ20.95,1
p-value |
χ20.95,m-k
p-value
|
| Exponential
|
193
|
146
|
10
|
3.84
0
|
18.3
0
|
| Beta Poisson
|
47.5
|
9
|
16.9
3.22e-07
|
| Neither the exponential nor beta-Poisson fits well; beta-Poisson is less bad.
|
|
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
|
6.21E-02
|
3.53E-02 |
4.06E-02 |
4.32E-02 |
1.09E-01 |
1.25E-01 |
1.80E-01
|
| N50
|
3.46E+07
|
9.76E+05 |
1.69E+06 |
2.40E+06 |
9.41E+08 |
2.13E+09 |
1.34E+10
|
|
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 248 (Salmonella Typhimurium)
Mice/ Salmonella strain 533 data [1]
| Dose |
Dead |
Survived |
Total
|
| 1E+04 |
20 |
180 |
200
|
| 1E+05 |
17 |
153 |
170
|
| 1E+06 |
11 |
29 |
40
|
| 3160000 |
6 |
24 |
30
|
| 1E+07 |
12 |
8 |
20
|
| 3.16E+07 |
17 |
3 |
20
|
| 1E+08 |
19 |
1 |
20
|
|
Goodness of fit and model selection
| Model |
Deviance |
Δ |
Degrees
of freedom |
χ20.95,1
p-value |
χ20.95,m-k
p-value
|
| Exponential
|
214
|
165
|
6
|
3.84
0
|
12.6
0
|
| Beta Poisson
|
48.7
|
5
|
11.1
2.56e-09
|
| Neither the exponential nor beta-Poisson fits well; beta-Poisson is less bad.
|
|
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
|
1.08E-01
|
6.19E-02 |
7.06E-02 |
7.52E-02 |
1.79E-01 |
1.98E-01 |
2.44E-01
|
| N50
|
9.66E+06
|
1.93E+06 |
2.43E+06 |
2.82E+06 |
5.38E+07 |
8.11E+07 |
2.13E+08
|
|
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 1.5 1.6 Meynell GG, Meynell EW (1958) The Growth of Micro-Organisms in vivo with Particular Reference to the Relation between Dose and Latent Period Journal of Hygiene 56(3): 323-346.
Acheson D and Hohmann EL (2001) Nontyphoidal Salmonellosis. Clinical Infectious Diseases 32(2), 263-269.
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.
Meynell GG and Meynell EW (1958) The growth of micro-organisms in vivo with particular reference to the relation between dose and latent period. Epidemiology & Infection 56(03), 323-346.
