TABLE 2.
Summary of MIC and resistance data for OXA-23 clone 1 and 2 isolates and comparator groups
| Clone (no. tested) | Geometric mean antibiotic MIC (μg/ml) and breakpointsa |
|||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AMK (8/16) | AMP (8/16) | CIP (0.5/1) | CTX (1/1) | CAZ (2/2) | GEN (2/4) | IPM (4/4) | MEM (4/4) | PIP (16/16) | PTZ (16/16) | SUL | MIN | TIG | COL (4/4) | |||||
| OXA-23 clone 1 (131-134) | 53.6 (0.5-64) | >64 (>64) | >8 (>8) | 108.2 (16-256) | 69.6 (4-256) | 28.4 (0.5-32) | 27.6 (8-32) | 28.2 (8-32) | >64 (>64) | 62 (1-64) | 16 (8-32) | 2.9 (1-16) | 0.67 (0.25-8) | 0.60 (0.5-2) | ||||
| OXA-23 clone 2 (19-22) | 2.4 (1-32) | >64 (>64) | >8 (>8) | >64 (>64) | >64 (>64) | 53 (32->64) | 16.5 (16->32 | 17 (16->32) | >64 (>64) | 128 (1-64) | 19.9 (16-32) | 1.1 (1-2) | 0.67 (0.25-8) | 0.28 (0.5-2) | ||||
| SE clone (53-54) | 11.9 (4-64) | >64 (>64) | >8 (>8) | 122 (64-256) | 70 (32-256) | 25.4 (4-32) | 2.9 (0.5-16) | 7.0 (1-32) | >64 (>64) | 58.3 (1-64) | 7.5 (2-32) | 5.5 (1-32) | 2.37 (1-16) | 0.68 (0.5-2) | ||||
| Acinetobacter survey, 2000 (443) | BM (0.12-128) | NT | BM (0.06->16) | 21.6 (0.25-64) | 11.3 (0.25-64) | BM (0.25-64) | 0.20 (0.03-64) | 0.38 (0.03-8) | 42.6 (2-128) | BM (2-128) | BM (1-64) | 0.30 (0.12-8) | 0.71 (0.03-16) | 0.47 (0.12-64) | ||||
Ranges are indicated in parentheses. Bimodal distributions (BM) with distinct resistant and susceptible populations are noted; in these cases, the geometric means are omitted, being meaningless. AMK, amikacin; AMP, ampicillin; CIP, ciprofloxacin; CTX, cefotaxime; CAZ, ceftazidime; GEN, gentamicin; IPM, imipenem; MEM, meropenem; PIP, piperacillin; PTZ, piperacillin-tazobactam; SUL, sulbactam; MIN, minocycline; TIG, tigecycline; COL, colistin. The British Society for Antimicrobial Chemotherapy's breakpoints are given parenthetically in the subheadings in the form “x/y,” meaning susceptible is ≤x μg/ml and resistant is >y μg/ml. The Society has no current breakpoint for minocycline or sulbactam versus Acinetobacter spp. and has adopted the European Committee on Susceptibility Testing's(EUCAST; http://www.eucast.org) view that there is as yet “insufficient evidence” to set breakpoints for tigecycline versus Acinetobacter spp. NT, not tested.