The efficacy of colistin monotherapy versus combination therapy with other antimicrobials against carbapenem-resistant Acinetobacter baumannii ST2 isolates

Abstract

This study aimed to investigate the efficacy of colistin both alone and in combination with either meropenem or levofloxacin against CRAB clinical isolates. The OXA carbapenemase genes and multilocus sequence typing were detected after 35 CRAB isolates biochemical identification. Then, the minimum inhibitory concentrations, minimum bactericidal concentrations, antibiotic interactions of the test antibiotics, and synergistic effects were determined by the checkerboard method and time-kill assays. The chromosomal gene bla _OXA-51-like was detected in all isolates, and bla _OXA-23-like and bla _OXA-24-like were present in 91.4% and 25.7% of the isolates, respectively. The combination of colistin and meropenem displayed the highest rate of synergy (51.4%) against the 35 isolates, while the colistin-levofloxacin combination showed a higher rate of indifference interaction (22.9%) than that of the colistin-meropenem (8.6%) combination. The synergistic effect of colistin against the CRAB isolates was confirmed. The combination of colistin with meropenem is recommended against CRAB isolates.

Keywords:

• Carbapenem-resistant Acinetobacter baumannii
• Colistin
• Multilocus sequence typing
• Synergy
• Antimicrobials
• Combination therapy

Disclosure statement

No potential conflict of interest was reported by the authors.

Biographical note

XLZ: https://www.ychcqmu.com/physician/2019/jnegXraw.html

Notes on contributors

Jiaying Li, a master's degree in Jiamusi University.The professional is Pathogen Biology, the research direction is the study of the mechanism of bacterial resistance.

Yanjun Fu, holds a master's degree in medicine and is currently the deputy director of the Clinical Microbiology Laboratory of the First Affiliated Hospital of Jiamusi University. A member of the hospital's anti-infection MDT team, an excellent team building project for basic research business expenses of Heilongjiang provincial undergraduate colleges, the backbone of the research team of bacterial resistance in Jiamusi University.

Jisheng Zhang, Associate professor, professional clinical laboratory diagnostics, master degree in biochemistry and molecular biology, deputy director of laboratory of Jiamusi University School of Medicine Mainly engaged in clinical immunological examination and diagnosis.

Yongxin Zhao, Graduated from Jiamusi University with a master's degree. Her research direction is the mechanism of bacterial drug resistance.

Xuecai Fan, Postgraduate of clinical laboratory diagnosis, the Second Affiliated Hospital of Jiamusi University, Heilongjiang Province, mainly studies the direction of bacterial drug resistance.

Lan Yu, a master's degree in Jiamusi University, China. The professional Laboratory medicine, the research direction is the study of the mechanism of bacterial resistance.

Yong Wang, Master tutor and deputy chief technician, Deputy Director of the Laboratory Department of the First Affiliated Hospital of Jiamusi University National Youth Member of the Clinical Microbiology Committee of the Chinese Society of Microbiology, member of the bacterial resistance mechanism group.

Xiaoli Zhang, Professor, supervisor of postgraduates majoring in clinical laboratory diagnostics, doctor of clinical laboratory diagnostics, postdoctor of immunology, director of the laboratory of Yongchuan Hospital affiliated to Chongqing Medical University, head of the bacterial resistance mechanism team of the innovation team of Heilongjiang University, professional clinical laboratory diagnostics, Mainly engaged in microbiological testing and diagnosis.

Chunjiang Li, Doctor of Science, postdoctoral fellow, supervisor of master student, professor, member of the Standing Committee of the Party Committee of Jiamusi University, vice president, and minister of the Ministry of Medicine Main research directions: bacterial resistance.

Data availability statement

Data available within the article

Additional information

Funding

This work was supported by Excellent Team of Young Teachers Foundation of Heilongjiang Province under Grant [number 2018-KYYWF-0916], Heilongjiang Province Undergraduate College and University funded the outstanding innovation team construction plan and Heilongjiang Provincial Health and Family Planning Commission on Scientific Research Project under Grant [number 2018-290].