TABLE 6.
Cephalosporin resistance in E. coli and P. aeruginosa conferred by a probable penicillin-binding protein gene homologue, pbpTET A6, recovered from a multidrug-resistant fosmid clone
| Species and strain | Vector | Genotypea |
MIC (μg/ml)b |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| pbpTET A6 | orf-12TET A6 | CAZ | CAX | FEP | TET | CTC | OTC | TYL | ERY | AZI | LIN | TIG | ||
| E. coli | ||||||||||||||
| EPI300T1R | pCC1FOS | − | − | 2 | 0.125 | 1 | 4 | 64 | 4 | 2,048 | 256 | 16 | 256 | 1 |
| MACRO-TET A6 | + | + | 8 | 0.125 | 1 | 32 | 256 | 64 | 4,096 | 512 | 32 | 512 | 4 | |
| MACRO-TET A6/Δorf-12::Tn | + | − | 8 | ND | ND | 4 | 64 | 4 | 2,048 | 256 | 16 | 256 | 1 | |
| MACRO-TET A6/ΔpbpTET A6::Tn | − | + | 2 | ND | ND | 32 | 256 | 64 | 4,096 | 512 | 32 | 512 | 4 | |
| DH10β | pUC19 | − | − | 2 | 0.125 | 1 | ND | ND | ND | ND | ND | ND | ND | ND |
| pCL050 | + | − | 32 | 0.5 | 4 | ND | ND | ND | ND | ND | ND | ND | ND | |
| P. aeruginosa PAO1 | pUCP19 | − | − | 4 | 16 | 1 | ND | ND | ND | ND | ND | ND | ND | ND |
| pCL051 | + | − | 128 | 32 | 4 | ND | ND | ND | ND | ND | ND | ND | ND | |
a
+, present; −, absent or transposon disrupted.
b
ND, not determined. MIC values higher than that for the corresponding empty-vector control are in bold. AZI, azithromycin; CAZ, ceftazidime; CAX, cefotaxime; CTC, chlortetracycline; ERY, erythromycin; FEP, cefepime; LIN, lincomycin; OTC, oxytetracycline; TET, tetracycline; TIG, tigecycline; TYL, tylosin.