title: In Vitro activities of combinations of rifampin with other antimicrobials against multidrug-resistant Acinetobacter baumannii.
abstract: The antimicrobial treatment of multidrug-resistant (MDR) Acinetobacter baumannii infections has become a great challenge for medical staff all over the world. Increasing numbers of MDR A. baumannii infections have been identified and reported, but effective clinical treatments for them are decreasing. The objective of this study was to investigate the in vitro activities of combinations of rifampin (an established antimicrobial) and other antimicrobials, including biapenem, colistin, and tigecycline, against 73 clinical isolates of MDR A. baumannii. In total, 73 clinical isolates of MDR A. baumannii were collected from two A-level general hospitals in Beijing, and the MICs of rifampin, biapenem, colistin, and tigecycline were determined. The checkerboard method was used to determine the fractional inhibitory concentration indices (FICIs), that is, whether the combinations acted synergistically against these isolates. The MIC50, MIC90, and MICrange of rifampin combined with biapenem, colistin, and tigecycline against the isolates were clearly lower than those for four antimicrobials (rifampin, biapenem, colistin, and tigecycline) that were used alone. Combinations of rifampin with biapenem, colistin, and tigecycline individually demonstrated the following interactions: synergistic interactions (FICI ≤ 0.5) for 31.51%, 34.25%, and 31.51% of the isolates, partially synergistic interactions (0.5 < FICI < 1) for 49.31%, 43.83%, and 47.94% of the isolates, and additive interactions (FICI = 1) for 19.18%, 21.92%, and 20.55% of the isolates, respectively. There were no indifferent (1 < FICI < 4) or antagonistic (FICI ≥ 4) interactions. Therefore, combinations of rifampin with biapenem, colistin, or tigecycline may be future therapeutic alternatives for the treatment of MDR A. baumannii infections.
authors.affiliation: Department of Pharmaceutical Care, Chinese PLA General Hospital, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Respiratory Diseases, Chinese PLA General Hospital, Beijing, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Pharmaceutical Care, Chinese PLA General Hospital, Beijing, China.
authors.forename: Tianlin
authors.initials: T
authors.lastname: Wang
authors.affiliation: Center of Medicine Clinical Research, Translational Medical Center, Chinese PLA General Hospital, Beijing, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Center of Medicine Clinical Research, Translational Medical Center, Chinese PLA General Hospital, Beijing, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Liang
authors.affiliation: Center of Medicine Clinical Research, Translational Medical Center, Chinese PLA General Hospital, Beijing, China 362337166@qq.com.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Respiratory Diseases, Chinese PLA General Hospital, Beijing, China.
authors.forename: Youning
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Center of Medicine Clinical Research, Translational Medical Center, Chinese PLA General Hospital, Beijing, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D004359:Drug Therapy, Combination; D006801:Humans; D008826:Microbial Sensitivity Tests; D012293:Rifampin / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D012293:Rifampin