Activities of colistin- and minocycline-based combinations against extensive drug resistant Acinetobacter baumannii isolates from intensive care unit patients

BMC Infectious Diseases

Research Article

Jian Li¹  De-mei Zhu²  Jun Huang²  Xiao-fang Liu²  Wang Liang²  Jing Zhang² 

[1]Facility for Anti-infective Drug Development and Innovation, Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia

[2]Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China

关键词: Minimum Inhibitory Concentration;    Rifampicin;    Minocycline;    Meropenem;    Colistin;   

DOI  :  10.1186/1471-2334-11-109

 received in 2010-12-13, accepted in 2011-04-27,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundExtensive drug resistance of Acinetobacter baumannii is a serious problem in the clinical setting. It is therefore important to find active antibiotic combinations that could be effective in the treatment of infections caused by this problematic 'superbug'. In this study, we analyzed the in vitro activities of three colistin-based combinations and a minocycline-based combination against clinically isolated extensive drug resistant Acinetobacter baumannii (XDR-AB) strains.MethodsFourteen XDR-AB clinical isolates were collected. The clonotypes were determined by polymerase chain reaction-based fingerprinting. Susceptibility testing was carried out according to the standards of the Clinical and Laboratory Standards Institute. Activities of drug combinations were investigated against four selected strains and analyzed by mean survival time over 12 hours (MST12 h) in a time-kill study.ResultsThe time-kill studies indicated that the minimum inhibitory concentration (MIC) of colistin (0.5 or 0.25 μg/mL) completely killed all strains at 2 to 4 hours, but 0.5×MIC colistin showed no bactericidal activity. Meropenem (8 μg/mL), minocycline (1 μg/mL) or rifampicin (0.06 μg/mL) did not show bactericidal activity. However, combinations of colistin at 0.5×MIC (0.25 or 0.125 μg/mL) with each of the above were synergistic and shown bactericidal activities against all test isolates. A combination of meropenem (16 μg/mL) with minocycline (0.5×MIC, 4 or 2 μg/mL) was synergitic to all test isolates, but neither showed bactericidal activity alone. The MST12 h values of drug combinations (either colistin- or minocycline-based combinations) were significantly shorter than those of the single drugs (p < 0.01).ConclusionsThis study indicates that combinations of colistin/meropenem, colistin/rifampicin, colistin/minocycline and minocycline/meropenem are synergistic in vitro against XDR-AB strains.

【 授权许可】

Unknown   
© Liang et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.