The Cerebrospinal fluid penetration of ceftobiprole has been studied in an animal model of meningitidis. Ceftobiprole is bactericidal, well tolerated and it has anti-biofilm activity. Altogether, these pharmacodynamics and pharmacokinetic properties of ceftobiprole are suitable for its use in case of External Ventricular Derivation(EVD)-related ventriculitis. Nowadays there are no human studies on the penetration and efficacy of ceftobiprole in the CSF. The study aims to evaluate characteristics of the CSF penetration of Ceftobiprole after intravenous administration in patients with EVD, that need for a concomitant infection this therapy (prescribed by an Infectious Diseases doctor).

According with Inclusion and Exclusion criteria, patients with an EVD and concomitant ceftobiprole therapy will be enrolled in the study.

In particular, ceftobiprole will be prescribed by an expert infectivologist, in accordance with the MHRA guidelines.

Once the patients will be enrolled, Ceftobiprole will be administered by 2 hr i.v. infusion at the following dosage:

• normal renal function: 500mg every 8 hr
• mild renal impairment (50-80mL/min): 500mg every 8 hours
• moderate (30-49mL/min): 500mg every 12 hours
• severe (<30mL/min): 250mg every 12 hours.

The following blood and CSF sample will be drowned only during the third dose of antibiotic therapy. Blood Samples (1 mL each) will be obtained at the following time points: before and at the end of infusion of ceftobiprole, then 0.5, 1, 2, 2.5, 3 and 4 hr after drug administration (total of 8 samples), using a single venous or arterial line cannulation. CSF samples: 0.5ml will be drawned from implanted EVD with a sterile field at the same blood sample time-point, and at 6, 8 and 10 hr after the end of drug administration (11 samples total).

CSF and blood will be spin-down at 3000 rpm for 10 minutes and then stored at -80°C.

Samples will be sent all in once by courier to Laboratory of Clinical Pharmacology and Pharmacogenetics, University of Turin, Department of Medical Sciences, Amedeo di Savoia Hospital, Turin (Italy) in order to determine the serum and CSF concentration.

Ceftobiprole concentrations (both in plasma/serum and CFS) will be analyzed with EMA validated LC-MS/MS methods.

MDR1 gene polymorphisms will be analyzed with RT-PCR instrument, using commercial genetic probes on the blood samples.

Inclusion Criteria:

• Age>18
• Patients with External Ventricular Derivation (EVD)
• Patients who receive ceftobiprole for any infection where Ceftobiprole could be used, as judged by an expert infectivologist
• Patients or their relatives/parents who consent to study participation

Exclusion Criteria:

• Patients with end-stage renal insufficiency
• Patients with a BMI>30
• Pregnancy
• Moribund patients
• Allergy to cephalosporine or ceftobiprole
• Refusal to participate in the study

Patient admitted in Intensive Care Unit or Neurosurgical Unit of Hospital "Spedali Civili di Brescia" (BS, Italy), according to Inclusion and Exclusion Criteria, with an EVD and concomitant Ceftobiprole therapy. When ceftobiprole will be administered i.v. for the first time, patients will be enrolled in the study.

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