In Vitro Synergistic Activity of Combinations of Tetrahydroisoquinolines and Treatment Antibiotics against Multidrug-Resistant Salmonella
Table 2
Percentage drug interactions of tetrahydroisoquinolines (THIQs) and antibiotics against seven multidrug-resistant Salmonella isolates.
Combinations
No. of MDR Salmonella isolates per interaction (n) (%)
Synergism n (%)
Additivity n (%)
Antagonism n (%)
No effect n (%)
Penicillins: ampicillin (AMP)
AMP-THIQ 1
4 (57.14)
3 (42.86)
0 (0)
0 (0)
AMP-THIQ 2
0 (0)
1 (14.29)
0 (0)
6 (85.71)
AMP-THIQ 3
0 (0)
0 (0)
0 (0)
7 (100)
AMP-THIQ 4
0 (0)
5 (71.43)
0 (0)
2 (28.57)
AMP-THIQ 5
0 (0)
1 (14.29)
0 (0)
6 (85.71)
Phenicols: chloramphenicol (CHL)
CHL-THIQ 1
5 (71.43)
2 (28.57)
0 (0)
0 (0)
CHL-THIQ 2
0 (0)
2 (28.57)
0 (0)
5 (71.43)
CHL-THIQ 3
0 (0)
0 (0)
0 (0)
7 (100)
CHL-THIQ 4
0 (0)
5 (71.43)
0 (0)
2 (28.57)
CHL-THIQ 5
0 (0)
3 (42.86)
0 (0)
4 (57.14)
Antifolates: sulphamethoxazole-trimethoprim (SXT)
SXT-THIQ 1
5 (71.43)
2 (28.57)
0 (0)
0 (0)
SXT-THIQ 2
0 (0)
2 (28.57)
0 (0)
5 (71.43)
SXT-THIQ 3
1 (14.29)
1 (14.29)
0 (0)
5 (71.43)
SXT-THIQ 4
0 (0)
5 (71.43)
0 (0)
2 (28.57)
SXT-THIQ 5
4 (57.14)
3 (42.86)
0 (0)
0 (0)
Fluoroquinolones: ciprofloxacin (CIP)
CIP-THIQ 1
0 (0)
7 (100)
0 (0)
0 (0)
CIP-THIQ 2
4 (57.14)
0 (0)
0 (0)
3 (42.86)
CIP-THIQ 3
0 (0)
0 (0)
5 (71.43)
2 (28.57)
CIP-THIQ 4
4 (57.14)
0 (0)
0 (0)
3 (42.86)
CIP-THIQ 5
0 (0)
0 (0)
6 (85.71)
1 (14.29)
Total assays (140)
27 (17)
42 (30)
11 (7.8)
60 (42)
Total combinations (20)
7 (35)
14 (70)
2 (10)
15 (75)
n = number of MDR Salmonella isolates which showed a given interaction; Distribution of interaction type based on the total number of THIQ-antibiotic combination assays against 7 MDR Salmonella isolates.
