Märtson, A.-G.da Silva Ferreira, A.R.Veringa, A.Liu, L.Wardill, H.R.Junier, L.A.T.van der Werf, T.S.Harmsen, H.J.M.Sturkenboom, M.G.G.Span, L.F.Tissing, W.J.E.Alffenaar, J.-W.C.2023-04-122023-04-122023Annals of Hematology, 2023; 102(2):421-4270939-55551432-0584https://hdl.handle.net/2440/137885Published online: 17 January 2023Gastrointestinal mucositis could potentially compromise drug absorption due to functional loss of mucosa and other pathophysiological changes in the gastrointestinal microenvironment. Little is known about this effect on commonly used anti-infectives. This study aimed to explore the association between different stages of gastrointestinal mucositis, drug exposure, and gut microbiota. A prospective, observational pilot study was performed in HSCT patients aged ≥ 18 years receiving anti-infectives orally. Left-over blood samples and fecal swabs were collected from routine clinical care until 14 days after HSCT to analyze drug and citrulline concentrations and to determine the composition of the gut microbiota. 21 patients with a median age of 58 (interquartile range 54-64) years were included with 252 citrulline, 155 ciprofloxacin, 139 fluconazole, and 76 acyclovir concentrations and 48 fecal swabs obtained. Severe gastrointestinal mucositis was observed in all patients. Due to limited data correlation analysis was not done for valacyclovir and fluconazole, however we did observe a weak correlation between ciprofloxacin and citrulline concentrations. This could suggest that underexposure of ciprofloxacin can occur during severe mucositis. A follow-up study using frequent sampling rather than the use of left-over would be required to investigate the relationship between gastrointestinal mucositis, drug exposure, and gut microbiome.en© The Author(s) 2023. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Gastrointestinal mucositisAutologous transplantStem cell transplantationMicrobiotaAntibiotic exposureHumansFluconazoleCiprofloxacinCitrullineAnti-Infective AgentsStem Cell TransplantationFollow-Up StudiesProspective StudiesPilot ProjectsMiddle AgedMucositisGastrointestinal MicrobiomeJournal article10.1007/s00277-023-05091-y2023-04-11632668Wardill, H.R. [0000-0002-6613-3661]