RT Journal Article T1 A Dalbavancin Lock Solution Can Reduce Enterococcal Biofilms After Freezing A1 Díaz-Navarro, Marta A1 Hafian Al-Homsi, Rama A1 Manzano, Irene A1 Pérez Granda, María Jesús A1 Cercenado Mansilla, Emilia A1 Pascual Izquierdo, María Cristina A1 Rodríguez, Carmen A1 Muñoz García, Patricia Carmen A1 Guembe, María AB IntroductionWe previously demonstrated the efficacy of a frozen dalbavancin–heparin (DH) lock solution against biofilms of staphylococci. However, as enterococci also commonly cause catheter-related bloodstream infections (C-RBSI), we assessed the bioactivity of frozen dalbavancin (D) and DH against enterococci.MethodsOver 6 months, we compared the bioactivity of a solution of DH (1 mg/ml) with that of D in terms of cfu counts and metabolic activity against biofilms of Enterococcus faecalis and Enterococcus faecium (four strains each). For each solution, we individually compared results obtained at each time point (months 3 and 6) with baseline (month 0). We also compared the median DH value of each variable at baseline and at months 3 and 6 of freezing with the values obtained for D alone. We used both statistical and clinical criteria when results were within 25% of the reference value.ResultsAt the end of the experiment (month 6), neither a statistically nor a clinically significant reduction in the bioactivity of D solution was observed in terms of cfu count and metabolic activity against enterococcal biofilms. Regarding the DH solution, we found both statistical and clinical significance in the median percentage reduction in metabolic activity between months 0 and 6 in E. faecalis strains (51.8% vs. 77.8%, P = 0.007). Moreover, after freezing, the DH solution lost significant bioactivity compared with the D solution, especially in E. faecalis.ConclusionA dalbavancin lock solution can be frozen for up to 6 months with no negative effect on its bioactivity against enterococcal biofilms. However, when combined with heparin, its efficacy was reduced. Therefore, we recommend that if lock therapy with frozen dalbavancin is used in the management of enterococcal C-RBSI, heparin should be added simultaneously at the time of catheter lock. PB Springer SN 2193-8229 YR 2022 FD 2022-01-16 LK https://hdl.handle.net/20.500.14352/134222 UL https://hdl.handle.net/20.500.14352/134222 LA eng NO Díaz-Navarro, M., Hafian, R., Manzano, I., Pérez-Granda, M. J., Cercenado, E., Pascual, C., Rodríguez, C., Muñoz, P., & Guembe, M. (2022). A dalbavancin lock solution can reduce enterococcal biofilms after freezing. Infectious Diseases and Therapy, 11(2), 743–755. https://doi.org/10.1007/s40121-021-00579-4 NO Funding. M. Guembe is supported by the Miguel Servet Program (ISCIII-MICINN, MS13/00268) of the Health Research Fund (FIS) of the Carlos III Health Institute (ISCIII), Madrid, Spain. M. Díaz-Navarro is supported by the Consejería de Educación, Juventud y Deporte de la Comunidad de Madrid and Fondo Social Europeo (PEJD-2020-AI_BMD-17971). The study was partially financed by grants from the ISCIII (PI18/00045) and the European Regional Development Fund (FEDER) ‘‘A way of making Europe’’. The Journal’s Rapid Service Fee was funded by the authors. NO Instituto de Salud Carlos III (España) NO Comunidad de Madrid NO Unión Europea DS Docta Complutense RD 27 may 2026