TABLE 2.
Accumulation of antibiotics by Salmonella serovar Typhimurium isolates
| Isolatea | Resistance phenotype or genotypeb | Accumulation (as ng of antibiotic/mg)c
|
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Ciprofloxacin
|
Chloramphenicol
|
Tetracycline
|
||||||||
| −CCCP | SD | +CCCP | −CCCP | SD | +CCCP | −CCCP | SD | +CCCP | ||
| L3 | Wild type | 102.2 | 16.8 | 112.4 | 42.8 | 6.8 | 35.9 | 15.1 | 1.4 | 17.7 |
| L5 | MAR; gyrA | 27.6 | 7.4 | 94.8 | 36.6 | 5.6 | 46.7 | 9.4 | 0.8 | 13.8 |
| L6 | MAR; dyes, detergents, hexane | 61.3 | 8.3 | 102.7 | 23.9 | 1.6 | 45.2 | 7.3 | 1.9 | 13.3 |
| L10 | MAR; dyes, detergents, hexane | 23.3 | 3.8 | 105.8 | 14.2 | 1.2 | 31.8 | 3.3 | 0.6 | 6.9 |
| L12 | MAR; dyes, detergents, hexane | 47.4 | 7.8 | 44.3 | 27.4 | 6.9 | 26.5 | 4.9 | 1.5 | 8.8 |
| L15 | MAR; dyes, detergents | 22.4 | 5.6 | 39.3 | 28.7 | 1.6 | 42.5 | 6.3 | 1.6 | 13.4 |
| L18 | MAR; acriflavine; gyrB | 89.9 | 2.9 | 96.3 | 34.2 | 4.9 | 55.5 | 7.7 | 0.3 | 13.5 |
| L19 | Type strain (NCTC 74) | 88.9 | ND | 38.1 | 39.3 | 9.5 | 9.9 | |||
| T39 | Parent strain | ND | ND | 15.8 | 25.7 | 4.0 | 11.7 | |||
| LX1054 | acrB mutant | ND | ND | 28.4 | 34.0 | 8.8 | 10.4 | |||
a
L3, pretherapy parent isolate; L5, L6, L10, L12, L15, and L18, posttherapy isolates. T39 (parent strain) and LX1054 (acrB mutant) were from Lacroix et al. (16).
b
gyrA, Piddock et al. (26); gyrB, Gensberg et al. (9); MAR, 2- to 256-fold more resistant to quinolones and six or seven unrelated agents than L3.
c
−CCCP, accumulation without CCCP; +CCCP, accumulation in the presence of CCCP; SD, standard deviation; ND, not done.