關於bacterial meningitis的敘述，下列何者錯誤？
CSF opening pressure常大於180 \mathrm{mmH}_{2}O
\mathrm{mmH}_{2}
CSF/serum glucose ratio大於0.4
CSF protein上升，常大於45 mg/dL
CSF Gram stain細菌染色之陽性率>50%
