Detection of Pathogenic Serogroups and Virulence Genes in Listeria monocytogenes Strains Isolated from Beef and Beef Products Retailed in Gauteng Province, South Africa, Using Phenotypic and Polymerase Chain Reaction (PCR)-Based Methods
Table 2
Frequency of detection of L. monocytogenes serogroups by the region, size of retail outlets, and type of beef and beef products.
Variable
No. of isolates of L. monocytogenes1
No. (%) of isolates belonging to serogroup
1/2a-3a
1/2c-3c
4b-4d-4e
Region
Pretoria North
10
2 (20.0)
1 (10.0)
7 (70.0)
Pretoria East
10
6 (60.0)
1 (10.0)
3 (30.0)
Pretoria West
9
7 (77.8)
0 (0.0)
2 (22.2)
Pretoria South
1
0 (0.0)
0 (0.0)
1 (100.0)
Pretoria Central
7
1 (14.3)
0 (0.0)
6 (85.7)
value
0.183
1
0.023
Type of retail outlet2
Supermarket chain
12
6 (50.0)
0 (0.0)
6 (50.0)
Large
7
2 (28.6)
2 (28.6)
3 (42.9)
Medium
7
3 (42.9)
0 (0.0)
4 (57.1)
Small
11
5 (45.5)
0 (0.0)
6 (54.5)
value
0.003
0.462
0.950
Type of beef and beef products
“Biltong”
2
0 (0.0)
0 (0.0)
2 (100.0)
Minced beef
16
6 (37.5)
1 (6.3)
9 (56.3)
Brisket
12
7 (58.3)
1 (8.3)
4 (33.3)
Cold beef
7
3 (42.9)
0 (0.0)
4 (57.1)
value
0.541
0.832
0.428
1Of a total of 37 isolates of L. monocytogenes. 2Supermarket chain: Over 1 outlet, large: 6 or more cashiers, medium: 3–5 cashiers, and small: 1–2 cashiers.
