In Vitro Activities of Colistin and Sitafloxacin Combinations against Multidrug-, Carbapenem-, and Colistin-Resistant <i>Acinetobacter baumannii</i> Using the Broth Microdilution Checkerboard and Time-Kill Methods

Drug-resistant <i>Acinetobacter baumannii (A. baumannii</i>) infections are a critical global problem, with limited treatment choices. This study aims to determine the in vitro activities of colistin–sitafloxacin combinations against multidrug-, carbapenem- and colistin-resistant <i&g...

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Main Authors: Vipavee Rodjun, Jantana Houngsaitong, Preecha Montakantikul, Taniya Paiboonvong, Piyatip Khuntayaporn, Pattareeya Yanyongchaikit, Pusana Sriyant
Format: Article
Language:English
Published: MDPI AG 2020-08-01
Series:Antibiotics
Subjects:
Online Access:https://www.mdpi.com/2079-6382/9/8/516
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Summary:Drug-resistant <i>Acinetobacter baumannii (A. baumannii</i>) infections are a critical global problem, with limited treatment choices. This study aims to determine the in vitro activities of colistin–sitafloxacin combinations against multidrug-, carbapenem- and colistin-resistant <i>A. baumannii</i> (MDR-AB, CRAB, CoR-AB, respectively) clinical isolates from tertiary care hospitals. We used the broth microdilution checkerboard and time-kill methods in this study. Synergy was found using both methods. The colistin–sitafloxacin combination showed synergy in MDR-AB, CRAB, and CoR-AB isolates (3.4%, 3.1%, and 20.9%, respectively). No antagonism was found in any type of drug-resistant isolate. The majority of CoR-AB isolates became susceptible to colistin (95.4%). The time-kill method also showed that this combination could suppress regrowth back to the initial inocula of all representative isolates. Our results demonstrated that the colistin–sitafloxacin combination might be an interesting option for the treatment of drug-resistant <i>A. baumannii</i>. However, further in vivo and clinical studies are required.
ISSN:2079-6382