TABLE 2.
AS-48 production and resistance from E. faecalis JH2-2 harboring the plasmids used in this work
| Plasmid | AS-48 production zone of inhibition (mm)a | Sensitivity to indicated amt (μg 5 μl−1) of AS-48b
|
|||||
|---|---|---|---|---|---|---|---|
| 0.5 | 1 | 3 | 6 | 9 | 18 | ||
| pMB2 (positive control) | 16 | R | R | R | R | R | R |
| pAM401 (negative control) | ND | S | S | S | S | S | S |
| pAM401-81 | 16 | R | R | R | R | R | R |
| pAM401-81::Tn5PA | ND | R | R | R | R | S | S |
| pAM401-81::Tn5B | ND | R | R | R | R | S | S |
| pAM401-81::Tn5C | 8 | R | R | R | R | S | S |
| pAM401-81X | 11 | R | R | R | R | R | R |
| pAM401-52 | 11 | R | R | R | S | S | S |
| pAM401-58 | ND | R | R | S | S | S | S |
| pAM401-81::Tn5PA/pMG36-Ac | 7 | R | R | R | R | S | S |
| pAM401-58/pMG36-Ac | ND | R | R | S | S | S | S |
| pAM401-81::Tn5B/pMG36-BCc | 11 | R | R | R | R | R | R |
a
AS-48 production was assayed in plates against the indicator strain E. faecalis JH2-2[pAM401] by using AS-48[pMB2] as a control (wild-type phenotype). ND, no detectable production.
b
To test AS-48 sensitivity, 5-μl spots containing different amounts of purified AS-48 were applied on lawns seeded with a standard inoculum of E. faecalis JH2-2 harboring different plasmids. The plates were examined for inhibition halos after 18 h of incubation at 37°C. R, resistant; S, sensitive.
c
Erythromycin was present during growth of the strains in liquid and solid media, and JH2-2[pAM401/pMG36e] was used as an indicator for AS-48 production.