{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,11]],"date-time":"2026-11-11T11:17:43Z","timestamp":1794395863325,"version":"4.9.0"},"reference-count":51,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,11,5]],"date-time":"2025-11-05T00:00:00Z","timestamp":1762300800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: Post-surgical central nervous system (CNS) infections are severe complications associated with high morbidity and mortality. Vancomycin is a key antibiotic used in their management. However, because of the restrictive properties of the blood\u2013brain barrier (BBB), plasma concentrations may not accurately reflect drug exposure in the brain extracellular fluid (ECF), the presumed site of infection. Cerebral microdialysis enables direct measurement of unbound drug levels in brain ECF. This study aimed to assess vancomycin penetration into brain ECF in patients with suspected or confirmed post-surgical CNS infection. Materials and Methods: Five patients with suspected or confirmed post-surgical CNS infections were enrolled. Paired brain ECF microdialysate and plasma samples (and cerebrospinal fluid (CSF) samples, when available) were collected over two consecutive days at vancomycin steady state. Vancomycin concentrations were determined using a homogeneous enzyme immunoassay and corrected for probe recovery based on in vitro calibration. Pharmacokinetic parameters, including mean concentrations and 24-h area under the concentration\u2013time curve (AUC24), were calculated for plasma and ECF, and ECF-to-plasma ratios were derived. Results: Two subgroups could be identified: patients with negligible ECF concentrations (\u201clow penetrators\u201d), and those with higher ECF levels (\u201chigh penetrators\u201d). Mean (SD) ECF-to-plasma concentration ratios were 0.07 (0.04) in \u201clow penetrators\u201d and 0.44 (0.10) in \u201chigh penetrators\u201d. The corresponding AUC24 ratios were 0.06 (0.03) and 0.40 (0.03), respectively. The presence of systemic inflammatory response syndrome (SIRS) was considered the most plausible factor differentiating these two subgroups. Conclusions: Vancomycin exposure in brain ECF demonstrated substantial interpatient variability in post-surgical CNS infections, with some patients showing minimal drug penetration.<\/jats:p>","DOI":"10.3390\/medicina61111989","type":"journal-article","created":{"date-parts":[[2025,11,5]],"date-time":"2025-11-05T16:09:47Z","timestamp":1762358987000},"page":"1989","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Vancomycin Penetration in Brain Extracellular Fluid of Patients with Post-Surgical Central Nervous System Infections: An Exploratory Study"],"prefix":"10.3390","volume":"61","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1103-1112","authenticated-orcid":false,"given":"Skaist\u0117","family":"\u017dukaitien\u0117","sequence":"first","affiliation":[{"name":"Institute of Physiology and Pharmacology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania"},{"name":"Kauno klinikos, Hospital of Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-8644-5767","authenticated-orcid":false,"given":"Karolis","family":"Bareikis","sequence":"additional","affiliation":[{"name":"Kauno klinikos, Hospital of Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"},{"name":"Department of Neurosurgery, Medical Academy, Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Simona","family":"Stankevi\u010di\u016bt\u0117","sequence":"additional","affiliation":[{"name":"Kauno klinikos, Hospital of Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akvil\u0117","family":"\u016asait\u0117","sequence":"additional","affiliation":[{"name":"Kauno klinikos, Hospital of Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Neringa","family":"Bal\u010di\u016bnien\u0117","sequence":"additional","affiliation":[{"name":"Kauno klinikos, Hospital of Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"},{"name":"Department of Intensive Care, Medical Academy, Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1019-7268","authenticated-orcid":false,"given":"Tomas","family":"Tamo\u0161uitis","sequence":"additional","affiliation":[{"name":"Kauno klinikos, Hospital of Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"},{"name":"Department of Intensive Care, Medical Academy, Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Romaldas","family":"Ma\u010diulaitis","sequence":"additional","affiliation":[{"name":"Institute of Physiology and Pharmacology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania"},{"name":"Kauno klinikos, Hospital of Lithuanian University of Health Sciences, 50161 Kaunas, Lithuania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1080\/02688690500145639","article-title":"Risk Factors for Neurosurgical Site Infections after Craniotomy: A Critical Reappraisal of Antibiotic Prophylaxis on 4,578 Patients","volume":"19","author":"Korinek","year":"2005","journal-title":"Br. 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