Causative organisms and diagnosis of infection according to the Centers for Disease Control definition
| Causative organism | EVD | LD | Σ (%) | Criterion 1 only (%) | Criterion 1+2 (%) |
| Σ (CoNS) | 13 | 16 | 29 (73) | 25 (86) | 4 (14) |
| Σ (S aureus), divided into | 3 | 4 | 7 (18) | 3 (43) | 4 (57) |
| S aureus, MSSA | 2 | 1 | 3 (8) | 2 (67) | 1 (33) |
| S aureus, MRSA | 1 | 3 | 4 (10) | 1 (25) | 3 (75) |
| Enterococcus faecalis | 1 | 0 | 1 (2.5) | 0 (0) | 1 (100) |
| Acinetobacter baumannii | 1 | 0 | 1 (2.5) | 0 (0) | 1 (100) |
| Pseudomonas aeruginosa | 1 | 0 | 1 (2.5) | 0 (0) | 1 (100) |
| Candida albicans | 1 | 0 | 1 (2.5) | 0 (0) | 1 (100) |
| Σ (all microorganism) | 20 | 20 | 40 | 28 (70) | 12 (30) |
Criterion 1, detection of a microorganism in CSF.
Criterion 2, at least one clinical symptom and at least one positive laboratory result and starting of antimicrobial therapy.
CoNS, coagulase negative staphylococci; EVD, external ventricular drain; LD, lumbar drain; MRSA, methicillin resistant Staphylococcus aureus; MSSA, methicillin sensitive Staphylococcus aureus.