TABLE 3.
DHFR gene analysis and MIC ranges of Tmp and dihydrophthalazine antifolates toward selected staphylococci
| Species | No. of strains | Met phenotypea | MIC range (μg/ml)
|
Presence of DHFR geneb
|
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tmp | BAL0030543 | BAL0030544 | BAL0030545 | dfrB | dfrC | dfrA (S1) | dfrD (S2) | dfrG (S3) | dfrA within SCCmec-N1 | |||
| S. aureus | 2 | Mets | ≤0.25 | ≤0.25 | 1 | 0.5 | + | − | − | ND | ||
| 1 | Metr | >128 | 0.5 | 1 | 1 | + (F98Y) | − | − | − | |||
| 3 | Metr | 128 | 1-2 | 2 | 0.5-2 | + | + | − | + | |||
| 11 | Metr | >128 | 1-4 | 1-4 | 1-4 | + | + | − | − | |||
| 2 | Metr | >128 | 32-64 | 64-128 | 64-128 | + | − | + | ND | |||
| S. epidermidis | 2 | Mets | ≤0.25-1 | ≤0.25 | <0.25-0.5 | <0.25-1 | + | − | − | ND | ||
| 3 | Mets | >128 | 0.5-4 | 1-4 | 1-4 | + (F98Y) | − | − | ND | |||
| 1 | Mets | >128 | ≤0.25 | 1 | 1 | + (F98Y) | + | − | ND | |||
| 5 | Mets | 32->128 | 0.5 | 1 | 1 | + | + | − | ND | |||
| 10 | Metr | >128 | 0.5-2 | 0.5-2 | 1-2 | + | + | − | − | |||
a
Met, methicillin.
b
The presence and absence of particular DHFR genes are indicated by “+” and “−”, respectively; the presence of an F98Y mutation and the presence of dfrA within SCCmec-N1 are indicated. ND, not done.