In vitro antimicrobial activity of polymyxin B combined with melatonin against polymyxin B-resistant Acinetobacter baumannii
10.11816/cn.ni.2025-240912
- VernacularTitle:多黏菌素B联合褪黑素对多黏菌素B耐药鲍曼不动杆菌的体外抗菌活性
- Author:
Yujie ZHAO
1
;
Qiaoping WU
;
Luozhu FENG
;
Yi LIU
;
Ling QIN
Author Information
1. 宁波大学附属李惠利医院检验科,浙江宁波 315040
- Publication Type:Journal Article
- Keywords:
Polymyxin B;
Melatonin;
Acinetobacter baumannii;
Drug resistance mechanism
- From:
Chinese Journal of Nosocomiology
2025;35(6):834-839
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE To observe the in vitro induced drug resistance mechanisms of polymyxin B-resistant Acin-etobacter baumannii and explore the in vitro antimicrobial activity of polymyxin B combined with melatonin.METHODS Totally 10 strains of polymyxin B-sensitive A.baumannii were clinically isolated from the Affiliated Li Huili Hospital of Ningbo university between Jan.2021 to Dec.2021 and were induced to the polymyxin B-resistant strains by means of in vitro induction method.The drug resistance mechanisms of the polymyxin B-resistant A.baumannii strains were explored by polymerase chain reaction(PCR)combined with sequencing analysis.The minimum inhibitory concentrations(MICs)of the single and joint use of polymyxin B and melatonin were detected by using broth microdilution checkerboard.The antibacterial effect of polymyxin combined with melatonin was e-valuated by calculating fractional inhibitory concentration index(FICI).The strains that showed the remarkable synergistic effect for the antimicrobial activity were chosen to determine the time-kill curves.RESULTS Among the polymyxin B-induced drug-resistant A.baumannii strains,there were gene mutations at various loci of polymyxin resistance genes pmrB,lpxA and lpxD.The MIC of polymyxin B against A.baumannii strains declined after the combined use of polymyxin B and melatonin.The combined use of the two drugs that showed synergistic effect for antimicrobial activity accounted for 80.00％(8/10),the additive effect 20.00％(2/10).The time-kill curve showed that the combined use of polymyxin B and melatonin showed remarkable antibacterial effect at the 24th hour.CONCLUSIONS The drug resistance gene mutations that are mediated by chromosomes are the major drug resist-ance mechanisms of the A.baumannii strains to polymyxin B.The combined use of polymyxin B and melatonin may reverse the drug resistance of the A.baumannii to polymyxin B.
