biostudies-literatureWang PNational Natural Science Foundation of China1379https://www.ebi.ac.uk/biostudies/studies/S-EPMC9598136biostudies-literatureUnknown11(10)<i>Acinetobacter baumannii</i> is one of the main pathogens causing nosocomial and community-acquired infections. Tigecycline is an important antibiotic for the treatment of multidrug-resistant <i>A. baumannii</i> infections, but strains resistant to tigecycline have also emerged. There are still many unclear questions concerning the mechanism of tigecycline resistance in <i>A. baumannii</i>. In this study, tigecycline-susceptible and tigecycline-intermediate strains were gradually cultured with sub-minimum inhibitory concentrations of tigecycline to select for tigecycline-resistant mutants, and a tigecycline-resistant strain was cultured under 42 °C to select for tigecycline-susceptible mutants. We found that the acquisition of tigecycline resistance affected the susceptibility of the strAntibiotics (Basel, Switzerland)Fitness Costs of Tigecycline Resistance in <i>Acinetobacter baumannii</i> and the Resistance Mechanism Revealed by a Transposon Mutation Library.PMC9598136NSFC81572041Wang PZou QWang HLiu CFeng CLu QfalseFitness Costs of Tigecycline Resistance in <i>Acinetobacter baumannii</i> and the Resistance Mechanism Revealed by a Transposon Mutation Library.<i>Acinetobacter baumannii</i> is one of the main pathogens causing nosocomial and community-acquired infections. Tigecycline is an important antibiotic for the treatment of multidrug-resistant <i>A. baumannii</i> infections, but strains resistant to tigecycline have also emerged. There are still many unclear questions concerning the mechanism of tigecycline resistance in <i>A. baumannii</i>. In this study, tigecycline-susceptible and tigecycline-intermediate strains were gradually cultured with sub-minimum inhibitory concentrations of tigecycline to select for tigecycline-resistant mutants, and a tigecycline-resistant strain was cultured under 42 °C to select for tigecycline-susceptible mutants. We found that the acquisition of tigecycline resistance affected the susceptibility of the str2022-01-01T00:00:00Z2022 Oct2025-04-19T12:03:30.079Z2025-04-19T12:03:30.079ZS-EPMC95981363629003810.3390/antibiotics11101379