Article Figures & Data
Figures
- FIG. 1.
L. monocytogenes biofilm formation measured by microtiter plate assay (crystal violet destaining). Bars represent average OD595 values and standard errors. Persistent strains are represented by gray bars, nonpersistent strains are represented by white bars, and all other strains have black bars. Division I consists of serotypes 1/2b and 4b, Division II consists of serotypes 1/2a and 1/2c, and strains belonging to serotypes 4c and 3a are listed as Other Serotypes.
- FIG. 2.
Ruthenium red carbohydrate stain of L. monocytogenes strain M39503A on glass (magnification, ×100). Crystal violet (purple) was used to stain bacterial cells, and ruthenium red (pink) was used to stain extracellular carbohydrate. The presence of pink stain between cells is consistent with an EPS matrix.
- FIG. 3.
SEM images of strain M39503A (high biofilm former) on stainless steel (A) and PVC (C) and strain M35584A (low biofilm former) on stainless steel (B) and PVC (D). The cracks visible under cells in panel B are artifacts in the stainless steel surface. Scale bars, 8.6μ m.
Tables
- TABLE 1.
L. monocytogenes strains used in this study
Isolate Serotype Divisiona Persistenceb Sourcec Isolate Serotype Divisiona Persistenceb Sourcec 15C18 1/2b I FDA 2492 1/2b I FDA 1159 1/2b I WASDOH ILSI-7d 1/2b I ILSI 1164 1/2b I WASDOH 9916B 1/2b I USDA ILSI-dd 1/2b I ILSI 9900104 1/2b I WASDOH 9900101 1/2b I WASDOH ILSI-6d 1/2b I ILSI 2475 1/2b I FDA M33027A 4b I NP USDA M13565A 4b I NP USDA M11056A 4b I NP USDA M35402A 4b I NP USDA 1161 4b I WASDOH V013368 4b I WADDL ILSI-24d 4b I ILSI 3515 4b I FDA 2172 4b I WASDOH 3365 4b I FDA 3276 4b I FDA F2365d 4b I CDC F5070 4b I CDC 1329 4b I WASDOH 3655 4b I FDA G1092 4b I CDC 9900094 4b I WASDOH 8807-X2 4b I WADDL 2150 4b I WASDOH 2140 4b I WASDOH M35584A 4c NP USDA 3280 4c FDA M36467A 4c USDA M32771C 1/2a II NP USDA M36407A 1/2a II NP USDA M36897A 1/2a II NP USDA M37010C 1/2a II NP USDA M36582B 1/2a II NP USDA M37952A 1/2a II NP USDA M36509A 1/2a II NP USDA M34058E 1/2a II NP USDA M36046A 1/2a II NP USDA M10867C 1/2a II NP USDA M12716B 1/2a II P USDA M32490G 1/2a II P USDA M35568E 1/2a II P USDA M10777A 1/2a II P USDA M32490E 1/2a P USDA M12716E 1/2a II P USDA M13235A 1/2a II P USDA M35303A 1/2a II P USDA M10868A 1/2a II P USDA M36012A 1/2a II P USDA M39503A 1/2a II P USDA 575 1/2a II USDA 1165 1/2a II WASDOH 2388 1/2a II FDA 1166 1/2a II WASDOH 750 1/2a II WASDOH 1445 1/2a II WASDOH 15cO3 1/2a II FDA 1157 1/2a II WASDOH 841 1/2a II WASDOH CI-136 1/2a II USDA ILSI-11 1/2a II ILSI 3313 1/2a II FDA ILSI-35 1/2a II ILSI 1163 1/2a II WASDOH 9900096 1/2c II WASDOH ILSI-17 1/2c II ILSI H9333 1/2c II CDC H7973 1/2c II CDC L028 1/2c II USDA H9066 1/2c II CDC G3321 1/2c II CDC 3326 1/2c II FDA H9067 1/2c II CDC G1127 3a CDC 15a90 3a FDA ↵ a Phylogenetic divisions are as defined by Piffaretti et al. (24).
↵ b L. monocytogenes isolates characterized as persistent (P) or nonpersistent (NP) as described by Muraoka et al. (19).
↵ c Sample sources are as follows: United States Department of Agriculture, Pullman, Wash. (USDA); Washington State Department of Health, Shoreline, Wash. (WASDOH); Centers for Disease Control and Prevention, Atlanta, Ga. (CDC); U.S. Food and Drug Administration, Bothel, Wash. (FDA); International Life Sciences Institute, L. monocytogenes strains collection (http://www.foodscience.cornell.edu/wiedmann/listeriadbase.htm ) (ILSI); WADDL, Washington Animal Disease Diagnostic Laboratory.
↵ d Strains common to this study and to that of Djordjevic et al. (9).
- TABLE 2.
Average OD for six serotypes of L. monocytogenes based on a crystal violet destaining biofilm assay
Serotype Assay results Mean OD SD Range Sample size 1/2a 0.713 0.381 1.90-0.22 35 1/2b 0.534 0.236 1.08-0.28 11 1/2c 0.774 0.354 1.35-0.22 9 3a 0.939 0.653 1.40-0.48 2 4b 0.537 0.366 1.53-0.09 20 4c 0.695 0.580 1.15-0.04 3
