TABLE 1.
Listeria monocytogenes strains used in this study (Henri et al., 2016).
| Group | Subgroup† | Isolate | Type of source | Detail of source | Origin (date) of isolation | MLST | Serogroup¥ | Lineage |
| Persistent | A | 1 | Food | Smoked-salmon | France (16/11/2011) | CC121 | IIa | II |
| 2 | Food | Catering plate | France (29/6/2011) | CC121 | IIa | II | ||
| 3 | FPE | Wipping of ground | France (7/5/2014) | CC121 | IIa | II | ||
| 4 | FPE | Wipping of food contact surface | France (1/8/2015) | CC121 | IIa | II | ||
| B | 5 | FPE | Food conveyor | France (30/8/2011) | CC11 | IIa | II | |
| 6 | FPE | Wipping of chain | France (24/9/2014) | CC11 | IIa | II | ||
| 7 | FPE | Chain bracket | France (1/12/2011) | CC11 | IIa | II | ||
| C | 8 | FPE | Sewer | France (1/6/2015) | CC155 | IIa | II | |
| 9 | FPE | Machine before cleaning procedure | France (22/10/2014) | CC155 | IIa | II | ||
| 10 | FPE | Sewer on floor | France (1/5/2015) | CC155 | IIa | II | ||
| 11 | Food | Sandwich (ham and butter) | France (1/8/2015) | CC155 | IIa | II | ||
| D | 12 | FPE | Factory environment | Norway (21/12/2006) | CC7 | IIa | II | |
| 13 | FPE | Factory environment | Norway (7/11/2007) | CC7 | IIa | II | ||
| 14 | FPE | Slicer machine before use | Norway (21/11/2007) | CC7 | IIa | II | ||
| 15 | FPE | Factory environment | Norway (25/10/2009) | CC7 | IIa | II | ||
| 16 | FPE | Factory environment | Norway (7/11/2009) | CC7 | IIa | II | ||
| 17 | FPE | Factory environment | Norway (21/11/2009) | CC7 | IIa | II | ||
| 18 | FPE | Factory environment | Norway (15/3/2010) | CC7 | IIa | II | ||
| 19 | FPE | Factory environment | Norway (22/9/2011) | CC7 | IIa | II | ||
| Prevalent | 1 | Food | Sandwich (ham and cheese) | Essonne, France (15/5/2008) | CC121 | IIa | II | |
| 2 | Food | Sliced tomato | Essonne, France (15/5/2008) | CC121 | IIa | II | ||
| 3 | Food | Ham | Val-de-Marne, France (7/3/2011) | CC121 | IIa | II | ||
| 4 | Food | Cheese (Gouda) | France (6/6/2003) | CC9 | IIc | II | ||
| 5 | Food | Spinach | Cote-d’Or, France (2/5/2005) | CC9 | IIc | II | ||
| 6 | Food | Sausage (Merguez) | France (25/8/2005) | CC9 | IIc | II | ||
| 7 | Food | Frozen onions | Vendee, France (20/1/2009) | CC8 | IIa | II | ||
| 8 | Food | Sausage meat | Guadeloupe, France (25/5/2010) | CC8 | IIa | II | ||
| 9 | Food | Smoked-haddock | Paris, France (25/10/2002) | CC2 | IVb | I | ||
| 10 | Food | White chocolate mousse | Alpes-Maritimes, France (1/3/2007) | CC2 | IVb | I | ||
| 11 | Food | Grilled vegetables | Essonne, France (26/9/2005) | CC1 | IVb | I | ||
| 12 | Food | Goat milk | Indre, France (16/12/2005) | CC1 | IVb | I | ||
| 13 | Food | Vacuum-packed goose breast fillet | Landes, France (1/7/2003) | CC3 | IIb | I | ||
| 14 | Food | Pastrami | Martinique, France (17/3/2010) | CC3 | IIb | I | ||
| 15 | FPE | Rag for surface wipping | Dordogne, France (28/1/2008) | CC4 | IVb | I | ||
| 16 | Food | Red pepper | Ille-et-Vilaine, France (19/5/2006) | CC4 | IVb | I | ||
| 17 | Food | Salad (Piedmontese) | Guadeloupe, France (25/5/2010) | CC5 | IIb | I | ||
| 18 | Food | Sausage meat with vegetable | Savoie, France (20/8/2008) | CC5 | IIb | I | ||
| 19 | Food | Potatoes | Gironde, France (16/3/2006) | CC6 | IVb | I | ||
| 20 | Food | Frozen tomatoes | Vendee, France (20/1/2009) | CC6 | IVb | I | ||
| Rare | 1 | Food | Cheese (Munster) | Yvelines, France (5/1/2012) | CC451 | IIa | II | |
| 2 | Not Known | Not Known | Ille-et-Vilaine, France (6/5/2009) | CC14 | IIa | II | ||
| 3 | Food | Cheese | Not Known | CC177 | IIa | II | ||
| 4 | Food | Salmon steak | Eure, France (17/7/2003) | CC19 | IIa | II | ||
| 5 | Food | Cheese | Not Known | CC199 | IIa | II | ||
| 6 | Food | Cheese | Herault, France (9/12/2008) | CC20 | IIa | II | ||
| 7 | Food | Cheese (Cantal) | Cantal, France (7/5/2009) | CC21 | IIa | II | ||
| 8 | Food | Salmon | Finistere, France (26/9/2005) | CC220 | IVb | I | ||
| 9 | Food | Cheese | Not Known | CC26 | IIa | II | ||
| 10 | Food | Cheese | Orne, France (29/4/2009) | CC26 | IIa | II | ||
| 11 | Food | Cheese | Orne, France (7/7/2009) | CC26 | IIa | II | ||
| 12 | Food | Salad (rice, corn, pepper, and ham) | Loiret, France (5/5/2011) | CC31 | IIa | II | ||
| 13 | FPE | Not known | Not Known | CC31 | IIa | II | ||
| 14 | Food | Sandwich (smoked-salmon and mimolette cheese) | Essonne, France (1/3/2006) | CC315 | IVb | I | ||
| 15 | Food | Cheese | Corse, France (9/10/2008) | CC412 | IIa | II | ||
| 16 | Food | Soy bean sprouts | Vendee, France (21/4/2011) | ST200 | IIa | II | ||
| 17 | Food | Cheese (Morbier) | Jura, France (5/9/2012) | ST517 | IIb | I | ||
| 18 | Food | Not Known | Not Known | ST13 | IIa | II | ||
| 19 | Food | Duck liver (foie gras) | Landes, France (8/3/2007) | ST13 | IIa | II |
†Isolates belonging to each subgroup were isolated from the same food premise and presumed to be persistent clones. ¥Serogroup IIa (serotype 1/2a and 3a), IIb (1/2b, 3b and 7), IIc (1/2c and 3c), and IVb (4b, 4ab, 4d, and 4e) by a multiplex PCR assay (Doumith et al., 2004).