Table 1.
Criteria for interpretation† | Clinical syndrome and route of administration | |||||
---|---|---|---|---|---|---|
Non-meningitis, i.v. penicillin (G)‡ | Meningitis, i.v. penicillin (G) | |||||
MIC (μg/ml) | MIC (μg/ml) | |||||
S | I | R | S | I | R | |
CLSI | ||||||
Old (pre-2008) breakpoints | ⩽0·06 | 0·12–1 | ⩾2 | ⩽0·06 | 0·12–1 | ⩾2 |
New breakpoints | ⩽2 | 4 | ⩾8 | ⩽0·06 | – | ⩾0·12 |
EUCAST | ||||||
No dosage categorization | – | – | – | ⩽0·06 | – | >0·06 |
Dosage: 1·2 g×4 | ⩽0·5 | – | >0·5 | – | – | – |
Dosage: 2·4 g × 4 or 1·2 g × 6 | ⩽1 | – | >1 | – | – | – |
Dosage: 2·4 g × 6 | ⩽2 | – | >2 | – | – | – |
CLSI, Clinical and Laboratory Standards Institute; EUCAST, European Committee on Antimicrobial Susceptibility Testing; i.v., intravenous; MIC, minimum inhibitory concentration; S, susceptible; I, intermediate; R, resistant.
Adapted from CLSI and EUCAST Clinical Breakpoint Table v. 2.0, valid from 1 January 2012.
Breakpoints in bold are those applied in the present study; for EUCAST 1·2 g × 4 was chosen because this most closely resembles the Belgian clinical choice of treatment.
In this column, the EUCAST breakpoint set for ‘pneumonia’ are used. EUCAST also has breakpoints for indications other than meningitis and pneumonia.