Combination tests of drug sensitivity for carbapenem-resistant Acinetobacter baumannii
10.13602/j.cnki.jcls.2024.04.06
- VernacularTitle:耐碳青霉烯类鲍曼不动杆菌联合药敏试验研究
- Author:
Aimei SU
1
;
Yongtao WEI
;
Dongping WANG
Author Information
1. 青岛市第八人民医院检验科,山东青岛 266100
- Keywords:
carbapenem-resistant Acinetobacter baumannii;
checkerboard testing;
combined antimicrobial susceptibility test;
fractional inhibitory concentration index
- From:
Chinese Journal of Clinical Laboratory Science
2024;42(4):267-271
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyze the distribution and drug resistance patterns of carbapenem-resistant Acinetobacter baumannii(CRAB),and evaluate the antimicrobial effects in vitro of colistin(COL)combined with cefoperazone/sulbactam(SCF),tigecycline(TGC),imipenem(IPM),meropenem(MEM),amikacin(AK),and levofloxacin(LEV)against CRAB to provide guidance for anti-infective therapy.Methods A total of 75 non-duplicate CRAB strains isolated from clinical specimens in 2022 were collected.WHONET 5.6 software was used for retrospective analysis of their clinical distribution and resistance profiles.Among them,25 strains were selected for combined antimicrobial susceptibility tests using broth microdilution to determine minimum inhibitory concentrations(MICs).The fractional inhibitory concentration(FIC)index was calculated based on checkerboard method to assess the combined effects.Results In 2022,a total of 145 Acinetobacter baumannii strains were isolated,including 75 CRAB(detection rate of 51.7％).CRAB was most prevalent in the patients over 70 years old(40.0％),mainly from blood(41.3％)and sputum(37.3％)specimens,and the intensive care unit was the top isolating department.All the 75 CRAB strains were resistant to piperacillin,piperacillin/tazobactam,ceftriaxone,1PM and MEM with resistance rates of 100％.The resistance rates for ampicillin/sulbactam,cefepime and tri-methoprim/sulfamethoxazole were all exceeded 95％.The resistance rates were 86.7％for LEV,82.7％for SCF,77.4％for AK,2.4％for TGC,and 0.0％for COL.The results of combined tests of 25 strains revealed the synergy rates of 92％and 80％for COL+SCF and COL+TGC respectively with sums of both synergy and additive rates of 100％.Synergy rates for COL combined with IPM,MEM,AK and LEV were 64％,72％,56％and 48％respectively.No antagonism was observed in any combination.Conclusion The drug resist-ance of CRAB exhibited high levels at our hospital,and the elderly and ICU patients were the major susceptible populations.Among all the combinations tests,COL+SCF showed optimal synergy while COL+LEV only had the lowest combined effect with the findings that warrants clinical consideration.
