Persistent and sporadic Listeria monocytogenes strains do not differ when growing at 37 °C, in planktonic state, under different food associated stresses or energy sources

Table 3 Number of the 95 L. monocytogenes isolates with a given growth status for each treatment condition, testing differences between persistent and sporadic isolates

Treatments^a	Growth (%)^b		Variable (%)		No Growth (%)		p-value^c
Treatments^a	Persistent	Sporadic	Persistent	Sporadic	Persistent	Sporadic	p-value^c
Stress Conditions in Nutritive Media (BHI)
Control	74 (100)	21 (100)	0	0	0	0	1.0
5% NaCl BHI	74 (100)	21 (100)	0	0	0	0	1.0
10% NaCl BHI	41 (55)	10 (47)	33 (45)	11 (53)	0	0	0.62
pH of 5.2	69 (93)	21 (100)	5 (7)	0	0	0	0.58
pH of 9.2	70 (95)	20 (95)	4 (5)	1 (5)	0	0	1.0
BAC 2 μg/mL	0	0	74 (100)	21 (100)	0	0	1.0
BAC 5 μg/mL	0	0	41 (55)	8 (38)	33 (45)	13 (62)	0.22
Energy Source Utilization (tested in chemically defined media [DM])
DM Glucose	38 (51)	8 (38)	34 (46)	13 (62)	2 (3)	0	0.46
DM Cellobiose	50 (68)	10 (48)	24 (32)	11 (52)	0	0	0.12
DM Fructose	38 (51)	9 (43)	36 (49)	12 (57)	0	0	0.62
DM Glycogen	24 (32)	9 (43)	41 (55)	11 (52)	9 (12)	1 (5)	0.55
DM Lactose	1 (1)	0	9 (12)	2 (10)	64 (87)	19 (90)	1.0
DM Sucrose	1 (1)	0	15 (20)	3 (14)	58 (78)	18 (86)	0.81

^a See Table 1 for treatment formulations
^b Numbers in parentheses are the percentage of the total persistent or total sporadic isolates
^c p-values were determined by Chi Square Test, or Fisher’s exact test if any cells contained less than five isolates

ISSN: 1471-2180