Table 2.
A total of 345 positive blood culture bottles inoculated with primarily sterile body fluids were tested with EUCAST’s antimicrobial susceptibility testing (RAST) directly feasible from positive blood culture at the Department for Infectious Diseases at the University Hospital Heidelberg, Germany. Inhibition zones from RAST were compared to MIC results obtained from Vitek2. Very major errors (VME), major errors (ME) and minor errors (MinE) were calculated. The EUCAST RAST guidelines only contain an ‘area of technical uncertainty’ (ATU) instead of intermediate results. Zone diameters falling into the ATU category cannot be used to predict susceptibility or resistance. For determining VME and ME, isolates with ATU interpretation were excluded. MinE were only determined for susceptible and resistant RAST response to intermediate Vitek results (S, susceptible; R, resistant; I, susceptible, increased exposure; ATU, area of technical uncertainty)
| RAST interpretation | Vitek MIC results | Errors | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| S | ATU | R | S | I | R | VME | ME | MinE | ||
| S. aureus (n = 197) | Cefoxitin |
92.4% (182/197) |
≤ 1% (1/197) |
7.1% (14/197) |
92.9% (183/197) |
/ |
7.1% (14/197) |
/ | / | / |
| Enterococcus spp. (n = 91) | Ampicillin |
44.0% (40/91) |
/ |
56.0% (51/91) |
47.3% (43/91) |
/ |
52.7% (48/91) |
/ |
7.0% (3/43) |
/ |
| Vancomycin |
69.2% (63/91) |
2.2% (2/91) |
28.6% (26/91) |
75.8% (69/91) |
/ |
24.2% (22/91) |
/ |
5.8% (4/69) |
/ | |
| E. coli (n = 38) | Piperacillin/tazobactam |
55.2% (21/38) |
31.6% (12/38) |
13.2% (5/38) |
78.9% (30/38) |
/ |
21.9% (8/38) |
/ | / | / |
| Ciprofloxacin |
50.0% (19/38) |
23.7% (9/38) |
26.3% (10/38) |
65.8% (25/38) |
10.5% (4/38) |
23.7% (9/38) |
/ | / |
6.9% (2/29) |
|
| Meropenem |
100% (38/38) |
/ | / |
100% (38/38) |
/ | / | / | / | / | |
| K. pneumoniae (n = 11) | Piperacillin/tazobactam |
36.4% (4/11) |
27.2% (3/11) |
36.4% (4/11) |
63.6% (7/11) |
/ |
36.4% (4/11) |
/ | / | / |
| Ciprofloxacin |
72.7% (8/11) |
/ |
27.3% (3/11) |
81.8% (9/11) |
/ |
18.2% (2/11) |
/ |
11.1% (1/9) |
/ | |
| Meropenem |
90.9% (10/11) |
/ |
9.1% (1/11) |
90.9% (10/11) |
/ |
9.1% (1/11) |
/ | / | / | |
| P. aeruginosa (n = 8) | Piperacillin/tazobactam |
87.5% (7/8) |
12.5% (1/8) |
/ |
100% (8/8) |
/ | / | / | / | / |
| Ciprofloxacin |
62.5% (5/8) |
25.0% (2/8) |
12.5% (1/8) |
87.5% (7/8) |
12.5% (1/8) |
/ | / |
14.3% (1/7) |
/ | |
| Meropenem |
75.0% (6/8) |
/ |
25.0% (2/8) |
87.5% (7/8) |
12.5% (1/8) |
/ | / |
28.6% (2/7) |
12.5% (1/8) |
|