TABLE 2.

Interaction of biotype 1A strains of various origins with epithelial cells and bone marrow-derived macrophages

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

^aResults are the mean of at least three independent experiments performed in duplicate. 

^bThe invasion assay was performed as described previously (16). Results are expressed as the percentage of the original bacterial inoculum. 

^cThe 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. 

^dDetermined 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. 

^eND, not determined.