Table 1

Characteristics and adherent-invasive Escherichia coli (AIEC) phenotype data for the B2 phylogroup E. coli strains used in the study

Strain	Serotype	Sequence type (ST)*	Phenotype†	Adhesion‡	Invasion§	Replication¶
12-1-TI12	O6: H31	127	AIEC	3.81±2.03	0.37±0.11	310.60±53.48
12-2-TI13	O6: H31	127	Non-AIEC	5.61±2.31	0.72±0.13	50.24±24.33
18-3 TI5	O25:H1	73	Non AIEC	0.25±0.10	0.04±0.01	179.30±76.61
18-4 TI12	O25:H1	73	Non AIEC	0.48±0.26	0.04±0.02	143.09±25.45
33-1-TI5	O16:H5	131	AIEC	6.68±2.28	0.10±0.03	867.09±77.11
36-1-TI13	O83:H4	429	Non AIEC	0.39±0.17	0.01±0.00	402.45±86.68
39-2-TI18	:	95	Non AIEC	0.07±0.03	0.01±0.00	1241.09±597.43
41-2-TI13	O17/O77:H41	720	Non AIEC	0.68±0.20	0.03±0.01	410.29±85.78
46-1-TI2	O1:H7	95	Non AIEC	0.20±0.06	0.01±0.01	707.98±358.64
52-1-TI3	O18:H7	95	AIEC	34.26±9.89	1.50±0.15	934.28±250.38
52-2-TI10	O75:H5	550	Non AIEC	0.11±0.08	0.01±0.00	153.11±31.56
54-1-TI6	O110:H27	1919	Non AIEC	9.30±5.13	0.07±0.03	408.36±65.09
55-1-AU4	O25:H4	131	Non AIEC	0.11±0.04	0.03±0.02	162.92±82.29
55-1-TI19	O25:H4	131	Non AIEC	0.05±0.05	0.03±0.01	325.74±164.91
57-3-TI5	O75:H5	537	AIEC	2.73±1.07	0.14±0.03	723.55±65.60
60-1-TI1	O75:H7	80	AIEC	7.08±1.35	0.13±0.06	333.25±107.54
61-1-TI1	O18:H7	95	AIEC	54.63±16.65	1.89±0.70	869.90±211.49
62-2-TI6	O1:H7	95	Non AIEC	1.24±0.33	0.14±0.02	90.74±35.52
63-1-TI1	O50O2:H18	963	Non AIEC	1.43±0.63	0.03±0.00	158.22±42.48
69-1 AU1	O46:H31	569	Non AIEC	0.66±0.15	0.07±0.03	79.02±12.65
69-1-TI1	O46:H31	569	Non-AIEC	0.60±0.13	0.10±0.03	91.37±30.65
70-2-TI12	O46:H31	569	Non-AIEC	1.22±0.58	0.06±0.01	45.49±5.68
72-6-Ti12	O46:H31	569	Non-AIEC	1.05±0.06	0.03±0.00	73.82±17.73
CD 1IM 3	O83:H6	2622	Non-AIEC	3.47±0.27	0.02±0.00	1163.70±203.59
CD 34 LN	O1:H7	95	Non-AIEC	0.14±0.06	0.02±0.00	458.485±105.69
CD 62 LN	O2:H4	95	AIEC	4.68±2.07	0.33±0.06	1686.33±307.68
H001	O8:H10	681	Non-AIEC	1.19±0.02	0.02±0.00	708.12±55.32
H020	O22:H1	73	Non-AIEC	1.33±0.07	0.08±0.04	1009.20±137.15
H223	O2:H6	141	AIEC	9.03±2.55	0.46±0.23	435.23±108.95
H252	O1:H7	95	Non-AIEC	3.47±0.20	0.09±0.04	74.23±30.72
H263	O2:H7	95	Non-AIEC	0.30±0.03	0.01±0.00	398.51±93.69
H296	O2:H7	95	Non-AIEC	0.45±0.04	0.00±0.00	792.33±78.74
H305	O18:H7	95	AIEC	27.52±6.10	0.63±0.24	730.65±68.44
H397	O1:H7	95	Non-AIEC	0.42±0.09	0.01±0.00	245.22±50.18
H413	O18:H7	95	Non-AIEC	0.91±0.05	0.02±0.00	717.92±411.86
H461	O18:H7	95	Non-AIEC	0.40±0.07	0.01±0.00	73.60±19.38
H504	O18ac:H7	95	AIEC	3.28±1.78	0.28±0.03	330.81±80.68
H588	** :H5	126	Non-AIEC	3.38±1.39	0.04±0.00	1141.51±65.45
H660	O1:H7	95	Non-AIEC	0.52±0.16	0.01±0.00	701.56±145.06
ED1a	O81:H27	452	Non-AIEC	0.25±0.07	0.05±0.01	68.34±30.95
LF82	O83:H1	135	AIEC	62.83±5.08	12.23±2.01	227.81±61.37
K-12	OR:H48	10	Non-AIEC	1.43±0.40	0.02±0.00	22.49±4.34

Results for adhesion, invasion and replication assays, data are means±SEM of independent experiments.
*Sequence type (ST) is based on the multilocus sequence type (MLST) scheme of Wirth et al.23
†Determination of E. coli strains as belonging to the AIEC pathovar was performed using the following criteria: (1) the ability to adhere to I-407 epithelial cells with an adhesion index equal or superior to 1 bacteria per cell, (2) the ability of the bacteria to invade I-407 with an invasion index equal or superior to 0.1% of the original inoculum, (3) the ability to survive and to replicate within THP-1 macrophages.
‡Mean number of bacteria per I-407 cell after 3 h of incubation.
§Mean percentage of the original inoculum after 1 h gentamicin treatment of infected I-407 cells.
¶Percentage of intracellular bacteria at 24 h post infection relative to the number after 1 h gentamicin treatment, defined as 100%.
**No O-antigen processing genes and/or H-antigen flagellin genes detected using the SeroType Finder tool (http://www.genomicepidemiology.org).
LN, lymph node.