Retraction notice to "Verapamil increases susceptibility of colistin-resistant Acinetobacter baumannii to colistin" [International Journal of Antimicrobial Agents 64 (2024), 107233].

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the authors. The authors have requested the retraction of the article due to unexpected identification of contaminated bacterial strains in their laboratory, including six strains used in this study. This issue was identified during a routine internal quality control procedure shortly after publication and has compromised the validity of the results in this study. The article's original Handling Editor and the journal's Editor in Chief have both agreed with the authors to retract the article to preserve the integrity of the scientific record. The authors deeply regret this incident and sincerely apologize for any inconvenience it may have caused. They remain committed to improving their internal review processes to avoid similar issues in the future.