TABLE 1.
Characteristics of strains producing class C β-lactamase PAC-1
| Strain | ST | MIC (μg/ml)a
|
Acquired β-lactamases | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TIC | TZPb | CAZ | FEP | CTb | CZAb | ATM | IPM | MEM | AMK | TOB | CIP | FOS | CST | |||
| 17.4313 | ST664 | >512 | 128 | >128 | >128 | >128 | >128 | 64 | 1 | 16 | >128 | >128 | 16 | 256 | 1 | PAC-1, OXA-10 |
| 17.4319 | ST664 | >512 | 256 | >128 | >128 | >128 | >128 | 64 | 16 | 64 | >128 | >128 | 16 | 256 | 1 | PAC-1, OXA-10 |
| 19.6465 | ST664 | >512 | 128 | >128 | >128 | >128 | >128 | 64 | 16 | 64 | >128 | >128 | >16 | 128 | 1 | PAC-1, OXA-10 |
| 19.6625 | ST664 | >512 | 128 | >128 | >128 | >128 | >128 | 128 | 2 | 32 | >128 | >128 | >16 | 128 | 1 | PAC-1, OXA-10 |
| PAO1 | 16 | 4 | 1 | 1 | ≤0.5 | 1 | 4 | 1 | ≤0.5 | 4 | 0.5 | ≤0.12 | 1 | |||
| PAO1ΔdacBc | 64 | 32 | 16 (1) | 8 (1) | 1 (0.5) | 2 (0.5) | 8 | 1 | ≤0.5 | ≤2 | 1 | ≤0.12 | 1 | |||
| PAO1(pUCP24) | 16 | 4 | 2 | 2 | ≤0.5 | 1 | 4 | 1 | ≤0.5 | ≤2 | 1 | ≤0.12 | 1 | |||
| PAO1(pUCP24blaPAC-1) | 32 | 16 | >128 (64) | >128 (32) | >128 (64) | >128 (64) | 8 | 1 | ≤0.5 | ≤2 | 1 | ≤0.12 | 1 | |||
a
MICs were determined by using customized Sensititre plates (Thermo Fisher Scientific). MIC values in parentheses were determined in the presence of 2,000 μg/ml of cloxacillin. TIC, ticarcillin; TZP, piperacillin-tazobactam; CAZ, ceftazidime; FEP, cefepime; CT, ceftolozane-tazobactam; CZA, ceftazidime-avibactam; ATM, aztreonam; IPM, imipenem; MEM, meropenem; AMK, amikacin; TOB, tobramycin; CIP, ciprofloxacin; FOS, fosfomycin; CST, colistin.
b
With a fixed concentration of 4 μg/ml tazobactam or avibactam.
c
PAO1ΔdacB was a gift from Antonio Oliver.