TABLE 1.
Phenotypic and genotypic characteristics of carbapenem-nonsusceptible A. baumanniia
| Group (no. of isolates) | Isolate | IS preceding the blaOXA gene |
MIC (mg/liter) |
Expression level of blaOXA-23b | Status of CarO | |||
|---|---|---|---|---|---|---|---|---|
| ISAba1- blaOXA-23 | ΔISAba1-ISAba10- blaOXA-23 | ISAba1- blaOXA-66 | IMP | MER | ||||
| Group I (13) | SC0701 | − | + | − | 32 | 32 | 4.6 | Intact |
| SC0702 | − | + | − | 32 | 32 | 3.2 | Lost | |
| SC0703 | − | + | − | 32 | 32 | 2.2 | Lost | |
| SC0704 | − | + | − | 32 | 32 | 4.9 | Lost | |
| SC0705 | − | + | − | 32 | 32 | 3.4 | Lost | |
| SC0706 | − | + | − | 32 | 32 | 4.0 | Lost | |
| SC0707 | − | + | − | 32 | 32 | 2.3 | Lost | |
| SC0708 | − | + | − | 32 | 32 | 2.0 | Lost | |
| SC0709 | − | + | − | 32 | 32 | 4.6 | Lost | |
| SC0710 | − | + | − | 32 | 32 | 1.8 | Lost | |
| SC0711 | − | + | − | 32 | 32 | 1.5 | Lost | |
| SC0712 | − | + | − | 32 | 32 | 2.2 | Lost | |
| SC0713 | − | + | − | 32 | 64 | 2.7 | Lost | |
| Group II (7) | SC0721 | + | − | − | 16 | 16 | 1.0 | NT |
| SC0722 | + | − | − | 16 | 16 | 1.1 | NT | |
| SC0723 | + | − | − | 16 | 16 | 1.4 | NT | |
| SC0724 | + | − | − | 16 | 16 | 1.3 | NT | |
| SC0725 | + | − | − | 8 | 16 | 1.4 | NT | |
| SC0726 | + | − | − | 16 | 16 | 1.1 | NT | |
| SC0727 | + | − | − | 16 | 16 | 1.0 | NT | |
| Group III (3) | SC0731 | NT | NT | + | 8 | 16 | NT | NT |
| SC0732 | NT | NT | + | 8 | 16 | NT | NT | |
| SC0733 | NT | NT | + | 8 | 16 | NT | NT | |
| ATCC 19606T | NT | NT | − | 0.25 | 1 | NT | Intact | |
a
Abbreviations: ΔISAba1, disrupted ISAba1; IMP, imipenem; MER, meropenem; +, positive; −, negative; NT, not tested.
b
Expression levels of the blaOXA-23 gene were measured by real-time quantitative PCR and normalized against the 16S rRNA gene.