TABLE 2.
Biotype 1A strain | Serotype | Invasion of Chinese hamster ovary cells (%)ab | Survival in macrophages (%)ac | Ability of bacteria to escape fromad:
|
|
---|---|---|---|---|---|
HEp-2 cells | Macrophages | ||||
Clinical | |||||
937 | O:6 | 0.24 | 37 | 2.3 × 109 | 9.7 × 109 |
T83 | O:5 | 0.49 | 62 | 8.6 × 108 | 2.2 × 109 |
61525 | O:6,30 | 1.10 | 36 | 1.2 × 109 | 4.5 × 109 |
A4183 | O:6 | 0.26 | 89 | 4.7 × 108 | 4.1 × 109 |
CIDC6512 | O:41,27 | 0.20 | 37 | 5.3 × 107 | 6.2 × 107 |
1267 | O:7,8 | 0.25 | 57 | 6.5 × 107 | 5.9 × 107 |
A3064 | O:6 | 0.70 | 42 | 7.1 × 108 | 6.1 × 108 |
AC12 | O:7,13 | 0.47 | 31 | 5.4 × 107 | 5.1 × 107 |
Y125 | O:5 | 0.15 | NDe | 2.4 × 107 | 4.3 × 107 |
A3047 | O:6 | 0.34 | ND | 5.2 × 107 | 7.9 × 107 |
A1379 | O:6 | 0.28 | ND | 3.9 × 107 | 5.9 × 107 |
AC22 | O:9b | 0.36 | ND | 2.1 × 107 | 2.3 × 107 |
1350 | O:10 | 0.29 | ND | 6.5 × 108 | 2.7 × 109 |
CIDC6516 | O:41,27 | 0.19 | ND | 4.7 × 108 | 8.1 × 108 |
CIDC5015 | O:46,34 | 0.20 | ND | <10 | <10 |
Nonclinical | |||||
AM5 | O:6 | 0.03 | 27 | <10 | <10 |
IP2222 | O:36 | 0.01 | 25 | <10 | <10 |
Eco88 | O:29 | 0.02 | 30 | <10 | <10 |
CIDC5569 | O:46,34 | 0.07 | ND | 4.2 × 107 | 7.1 × 107 |
CIDC7134 | O:6,31 | 0.50 | 53 | 2.1 × 108 | 4.3 × 108 |
IP1477 | O:6,31 | 0.02 | 29 | <10 | <10 |
AM2 | O:5 | 0.02 | 20 | <10 | <10 |
AM8 | O:13,15 | 0.06 | 41 | <10 | <10 |
IP500 | O:10,34 | 0.11 | 32 | <10 | <10 |
9741 | O:5 | 0.07 | ND | <10 | <10 |
CIDC2064 | O:5 | 0.37 | ND | 3.1 × 109 | 5.4 × 109 |
But | O:5 | 0.08 | ND | <10 | <10 |
Results are the mean of at least three independent experiments performed in duplicate.
The invasion assay was performed as described previously (16). Results are expressed as the percentage of the original bacterial inoculum.
The method for determining bacterial survival in macrophages is given in Materials and Methods. Results are expressed as the percentage of the number of bacteria recovered at T = 24 h relative to the number of bacteria at T = 0 h.
Determined by using the escape assay as described in Materials and Methods. Results are expressed as the number of CFU per milliliter of culture medium after 18 h of incubation.
ND, not determined.