In vitro reduction of antibacterial activity of tigecycline against multidrug-resistant Acinetobacter baumannii with host stress hormone norepinephrine

摘要: Abstract The host stress hormone norepinephrine (NE), also called noradrenaline, is reported to augment bacterial growth and pathogenicity, but few studies have focused on the effect of NE activity antimicrobials. aim this study was clarify whether affects antimicrobial against multidrug-resistant Acinetobacter baumannii (MDR-AB). Time–kill tigecycline (TIG) colistin (COL) MDR-AB as well assays for factors contributing antibiotic resistance were performed using clinical strains both in presence absence 10 µM NE. In addition, expression three efflux pump genes ( adeB , adeJ adeG ) analysed by quantitative reverse transcription PCR. Viable cell counts TIG-supplemented medium containing significantly increased compared with those without contrast, had little influence viable COL. NE-supplemented resulted an ca. 2 log increase numbers adhering polyurethane, silicone polyvinylchloride surfaces. Amounts biofilm 3-fold higher than Expression gene upregulated 4–6-fold conclusion, augmented markedly reduced vitro antibacterial TIG MDR-AB. These findings suggest that treatment may contribute failure therapy patients infections.