Table 1.
Molecular characterization of drug resistance genes and antibiotic susceptibility profile of the 19 A. baumannii isolates responsible for infection in pets and horses
| Molecular analysis of resistance genesa |
MIC (mg/L)b |
|||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Strain, STs | IC | aIEF (pI) | blaOXA-Ab | blaADC | blaTEM | ISAba1 | IS1133 | IntI | aacC1 | aadA1 | aacC2 | aadB | GyrA | ParC | CarO | CTX | CAZ | FEP | TZP | IPM | MEM | AMK | GEN | TOB | CIP | SXT | TET | PolB |
| Km1008-06, ST12 | II | 9.5, 5.4 | OXA-66 | ADC-25 | TEM-1 | +c | + | − | − | − | + | − | Ser83Leu | Ser80Leu | = | 4 | 4 | 4 | ≤4 | ≤0.5 | ≤1 | 4 | ≥32 | 4 | ≥4 | ≥320 | ≥16 | 1 |
| Km1016-09, ST12 | II | 9.5, 9.0, 6.5 | OXA-66 | ADC-25 | — | +c | + | − | − | − | + | − | Ser83Leu | Ser80Leu | = | 4 | 2 | 4 | 32 | 8 | 8 | ≤2 | ≥32 | ≤1 | ≥4 | ≥320 | ≥16 | 1 |
| Km1022-06, ST12 | II | 9.5, 5.4 | OXA-66 | ADC-25 | TEM-1 | +c | + | − | − | − | + | − | Ser83Leu | Ser80Leu | = | 4 | 2 | 4 | ≤4 | ≤0.5 | ≤1 | 4 | ≥32 | 4 | ≥4 | ≥320 | ≥16 | 1 |
| Km408-05, ST12 | II | 9.5, 5.4 | OXA-66 | ADC-25 | TEM-1 | +c | + | − | − | − | + | − | Ser83Leu | Ser80Leu | = | 8 | 4 | 8 | 16 | ≤0.5 | ≤1 | ≤2 | ≥32 | ≤1 | ≥4 | 40 | ≥16 | 1 |
| Km58-05, ST12 | II | 9.5, 5.4 | OXA-66 | ADC-25 | TEM-1 | +c | + | − | − | − | + | − | Ser83Leu | Ser80Leu | = | 4 | 4 | 8 | 8 | ≤0.5 | ≤1 | ≤2 | ≥32 | ≤1 | ≥4 | 40 | ≥16 | 1 |
| OD474-06, ST12 | II | 9.5, 6.5, 5.4 | OXA-66 | ADC-25 | TEM-1 | +c | + | − | − | − | + | − | Ser83Leu | Ser80Leu | = | 64 | 64 | 16 | 32 | 1 | ≤1 | ≤2 | ≥32 | ≤1 | ≥4 | 40 | ≥16 | 0.5 |
| Km410-05, ST12 | II | 9.5, 6.5, 5.4 | OXA-66 | ADC-25 | TEM-1 | +c,d | + | − | − | − | + | − | Ser83Leu | Ser80Leu | = | ≥128 | 64 | 16 | ≥128 | 4 | 4 | ≤2 | ≥32 | ≤1 | ≥4 | 160 | ≥16 | 1 |
| Km875-06, ST12 | II | 9.5, 5.4 | OXA-66 | ADC-25 | TEM-1 | + | − | − | − | − | + | − | Ser83Leu | Ser80Leu | = | 8 | 4 | 8 | 8 | ≤0.5 | ≤1 | 4 | ≥32 | 4 | ≥4 | ≥320 | ≥16 | 1 |
| Km765-04, ST10 | II | 9.5, 6.5 | OXA-66 | ADC-25 | TEM-1 | +d | − | − | − | − | − | − | Ser83Leu | Ser80Leu | = | ≥128 | 64 | 16 | ≥128 | 2 | ≤1 | 4 | ≤4 | ≤1 | ≥4 | ≥320 | ≥16 | 1 |
| Km693-07, ST20 | NI | 9.5 | OXA-95 | ADC-26 | TEM-1 | − | − | − | − | − | − | − | = | = | = | 8 | 4 | 2 | ≤4 | ≤0.5 | ≤1 | ≤2 | ≤4 | ≤1 | ≤1 | ≤ 20 | ≤1 | ≤0.25 |
| Km323-09, ST15 | I | 9.5, 9.0, 6.5, 5.4 | OXA-69 | ADC-11 | TEM-1 | − | + | +e | + | + | − | − | Ser83Leu | Ser80Leu | Ile74Leu, Glu217Lys | 8 | 4 | 8 | 32 | 8 | 4 | ≤2 | ≥32 | ≤1 | ≥4 | ≤ 20 | ≤1 | 0.5 |
| Km732-08, ST15 | I | 9.0, 5.4 | OXA-69 | ADC-11 | TEM-1 | − | − | +e | + | + | − | − | Ser83Leu | Ser80Leu | Glu217Lys | 4 | 2 | 4 | ≤4 | ≤0.5 | ≤1 | ≤2 | ≥32 | ≤1 | ≥4 | ≥320 | ≥16 | 1 |
| Km1492-04, ST15 | I | 9.0 | OXA-69 | ADC-11 | TEM-1 | − | − | +e | + | + | − | − | Ser83Leu | Glu84Lys | Ser214Thr | 16 | 8 | 16 | 32 | ≤0.5 | ≤1 | 8 | ≥32 | 2 | ≥4 | ≥320 | ≥16 | 1 |
| Km1245-05, ST15 | I | 9.0, 5.4 | OXA-69 | ADC-11 | TEM-1 | − | − | +e | + | + | − | − | = | = | Glu217Lys | 8 | 4 | 8 | ≤4 | ≤0.5 | ≤1 | ≤2 | ≥32 | ≤1 | ≤1 | 80 | 2 | 1 |
| Km183-05, ST15 | I | 9.0, 5.4 | OXA-69 | ADC-11 | TEM-1 | − | − | +e | + | + | − | − | = | = | Glu217Lys | 8 | 4 | 4 | 8 | ≤0.5 | ≤1 | ≤2 | ≥32 | ≤1 | ≤1 | ≥320 | ≥16 | 1 |
| Km1887-04, ST15 | I | 9.0, 5.4 | OXA-69 | ADC-11 | TEM-1 | − | − | +e | + | + | − | − | = | = | Glu217Lys | 8 | 4 | 4 | ≤4 | ≤0.5 | ≤1 | 4 | ≥32 | ≤1 | ≤1 | ≥320 | ≥16 | 1 |
| Km456-05, ST15 | I | 9.0 | OXA-69 | ADC-11 | TEM-1 | − | − | +e | + | + | − | + | = | = | Glu217Lys | 2 | 1 | 4 | ≤4 | ≤0.5 | ≤1 | ≤2 | ≥32 | ≥16 | ≤1 | 160 | ≥16 | 1 |
| Km1873-06, ST15 | I | 9.0, 5.4 | OXA-69 | ADC-11 | TEM-1 | + | − | +e | + | + | − | + | = | = | Glu217Lys | 4 | 2 | 8 | ≤4 | ≤0.5 | ≤1 | ≤2 | ≥32 | ≥16 | ≤1 | ≥320 | ≥16 | 1 |
| Km57-09, ST15 | I | 9.0, 5.4 | OXA-69 | ADC-11 | TEM-1 | − | − | +e | + | + | − | + | = | = | Glu217Lys | 4 | 4 | 4 | ≤4 | ≤0.5 | ≤1 | 8 | ≥32 | ≥16 | ≤1 | ≥320 | ≥16 | 1 |
IC, international clone; NI, not included among the three international clones; +, positive; −, negative; CTX, cefotaxime; CAZ, ceftazidime; FEP, cefepime; TZP, piperacillin/tazobactam; IPM, imipenem; MEM, meropenem; AMK, amikacin; GEN, gentamicin; TOB, tobramycin; CIP, ciprofloxacin; SXT, trimethoprim/sulfamethoxazole; TET, tetracycline; PolB, polymyxin B.
aCarO, GyrA and ParC proteins are reported with their amino acid substitutions, otherwise they are reported as equal (=) to the reference sequences (i.e. CP000863, X82165 and X95819, respectively). The remaining resistance genes tested (see the Molecular methods section) are not reported because they were not detected in any of the A. baumannii isolates.
bInterpretation of MICs according to 2011 EUCAST criteria (S, susceptible):17 TZP (criteria not available); CTX, CAZ and FEP (susceptibility testing not recommended); IPM and MEM (S, ≤2 mg/L); AMK (S, ≤8 mg/L); GEN and TOB (S, ≤4 mg/L); CIP (S, ≤1 mg/L); SXT (S, ≤2/38 mg/L); TET (susceptibility testing not recommended); and PolB (S, ≤2 mg/L). Data regarding AMK, TOB, SXT, TET and PolB were obtained using the Vitek 2 system.
cISAba1 was upstream of blaOXA-Ab.
dISAba1 was upstream of blaADC.
eThe class I integron carried a 2.6 kb cassette with the aacC1-orfX-orfX′-aadA1 gene structure.