Table 4.
Detection of cpe-positive cells in enrichment culture samplesa
| Expt | Molecular method | Detection of cpe-positive cells in: |
No. of cells added/amt of sample (g) | Type of meat sample | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Contaminated samples at incubation time (h) of: |
Noncontaminated samples at incubation time (h) of: |
|||||||||||||
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 24 | 0 | 24 | ||||
| 1 | PCR | − | − | − | − | − | + | + | NT | + | − | − | 1.5/20 | Ground beef |
| Nested PCR | − | − | − | − | + | + | + | NT | + | − | − | |||
| Real-time PCR | − | − | − | − | + | + | + | NT | + | − | − | |||
| LAMP | − | − | − | − | + | + | + | NT | + | − | − | |||
| 2 | PCR | − | − | − | − | + | + | + | NT | + | − | − | 20/20 | Ground pork |
| Nested PCR | − | − | − | + | + | + | + | NT | + | − | − | |||
| Real-time PCR | − | − | − | − | + | + | + | NT | + | − | − | |||
| LAMP | − | − | − | − | − | + | + | NT | + | |||||
| 3 | PCR | − | − | − | − | − | − | + | NT | + | − | − | 38/20 | Ground chicken |
| Nested PCR | − | − | − | − | − | − | + | NT | + | − | − | |||
| Real-time PCR | − | − | − | − | − | + | + | NT | + | − | − | |||
| LAMP | − | − | − | − | − | − | + | NT | + | − | − | |||
| 4 | PCR | − | − | − | − | + | + | + | NT | + | − | − | 26/20 | Ground beef |
| Nested PCR | − | − | − | + | + | + | + | NT | + | − | − | |||
| Real-time PCR | − | − | − | − | + | + | + | NT | + | − | − | |||
| LAMP | − | − | − | + | + | + | + | NT | + | − | − | |||
| 5 | PCR | − | − | − | − | + | + | + | NT | + | − | − | 35/20 | Ground pork |
| Nested PCR | − | − | − | + | + | + | + | NT | + | − | − | |||
| Real-time PCR | − | − | − | + | + | + | + | NT | + | − | − | |||
| LAMP | − | − | − | − | − | + | + | NT | + | − | − | |||
| 6 | PCR | − | − | − | − | − | + | + | NT | + | − | − | 50/20 | Ground chicken |
| Nested PCR | − | − | − | − | + | + | + | NT | + | − | − | |||
| Real-time PCR | − | − | − | − | + | + | + | NT | + | − | − | |||
| LAMP | − | − | − | − | + | + | + | NT | + | − | − | |||
| 7 | PCR | − | − | − | − | − | + | + | + | + | − | − | 6.5/20 | Ground beef |
| Nested PCR | +b | − | − | − | + | + | + | + | + | − | − | |||
| Real-time PCR | − | − | − | − | + | + | + | + | + | − | − | |||
| LAMP | +b | − | − | − | + | + | + | + | + | − | − | |||
| 8 | PCR | − | − | − | − | − | + | + | + | + | − | − | 1.8/20 | Ground pork |
| Nested PCR | − | − | − | − | − | + | + | + | + | − | − | |||
| Real-time PCR | − | − | − | − | − | + | + | + | + | − | − | |||
| LAMP | − | − | − | − | − | + | + | + | + | − | − | |||
| 9 | PCR | − | − | − | − | − | − | − | + | + | − | − | 2.4/20 | Ground chicken |
| Nested PCR | − | − | − | − | − | − | − | + | + | − | − | |||
| Real-time PCR | − | − | − | − | − | − | + | + | + | − | − | |||
| LAMP | − | − | − | − | − | + | + | + | + | − | − | |||
| 10 | PCR | − | − | − | − | + | + | + | + | + | − | − | 5.0/20 | Ground pork |
| Nested PCR | − | − | − | + | + | + | + | + | + | − | − | |||
| Real-time PCR | − | − | − | − | + | + | + | + | + | − | − | |||
| LAMP | − | − | − | − | + | + | + | + | + | − | − | |||
| 11 | PCR | − | − | − | − | + | + | + | + | + | − | − | 4.0/20 | Ground chicken |
| Nested PCR | − | − | + | + | + | + | + | + | + | − | − | |||
| Real-time PCR | − | − | − | − | − | + | + | + | + | − | − | |||
| LAMP | − | − | − | − | + | + | + | + | + | − | − | |||
| 12 | PCR | − | − | − | − | − | − | + | + | + | − | − | 8.5/20 | Ground beef |
| Nested PCR | − | − | − | − | − | + | + | + | + | − | − | |||
| Real-time PCR | − | − | − | − | + | + | + | + | + | − | − | |||
| LAMP | − | − | − | − | + | + | + | + | + | − | − | |||
a
For experiments 1 to 6, a 107-fold dilution of a culture of chromosomal cpe strain NCTC8239 grown overnight in TGY medium was used; for experiments 7 to 9, a 105-fold dilution of chromosomal cpe strain NCTC8239 grown overnight in Duncan-Strong medium was used after heat inactivation at 75°C for 20 min for the selection of spores; for experiments 10 to 12, a 107-fold dilution of plasmid cpe strain T16 grown overnight in TGY medium was used. NT, not tested.
b
This specimen might contain a sufficient number of heat-killed cpe-positive cells for the detection of cpe with molecular assays.