替加环素、米诺环素、多黏菌素B对碳青霉烯类敏感性降低和不敏感鲍曼不动杆菌体外抗菌活性

In vitro activity of tigecycline,minocycline and polymyxin B against Acinetobacter baumannii with decreased susceptibility or nonsusceptibility to carbapenems

目的调查替加环素、米诺环素、多黏菌素B等对碳青霉烯类抗生素敏感性降低鲍曼不动杆菌（CDSAB）和碳青霉烯不敏感鲍曼不动杆菌（CNSAB）体外抗菌活性，为临床治疗该类菌感染提供依据。方法采用琼脂稀释法检测替加环素、米诺环素、多黏菌素B等15种抗菌药物对2002-2009年深圳市人民医院临床分离56株CDSAB（美罗培南和亚胺培南MIC=1～4mg／L）和178株CNSAB（美罗培南或亚胺培南MIC≥8mg／L）的最低抑菌浓度（MIC），采用WHONET5．6软件分析处理数据。结果多黏菌素B对CDSAB和CNSAB体外抗菌活性最高，细菌对其均100％敏感，MIC50和MIC90均为1mg／L，其次为替加环素和米诺环素，约80％CDSAB对二者敏感或中介，MIC50／MIC90分别为4／8mg／L和8／16mg／L；约95％CNSAB对替加环素和米诺环素敏感或中介，MIC50／MIC90分别为4／4mg／L和4／8mg／L。结论多黏菌素B、替加环素和米诺环素对碳青霉烯类抗生素敏感性降低和不敏感鲍曼不动杆菌具有较强的体外抗菌活性。

Objective The in vitro activity of tigecycline, minocycline, polymyxin B and other comparators against Acinetobact-er baumannii with decreased susceptibility or nonsusceptihility to carbapenems was compared {or better clinical management of such infections. Methods Agar dilution method was used to determine the minimum inhibitory concentrations （MICs） of 15 an-timicrobial agents against A. baumannii collected during the period from 2002 to 2009 in Shenzhen People＇s Hospital. A total of 56 strains were found with decreased susceptibility to carbapenems, which was defined as imipenem MIC = 1 to 4 mg/L and meropenem MIC = 1 to 4 mg/L. Overall, 178 strains were identified as carbapenem-non-susceptible A. baumannii, which was defined as imipenem MIC ≥ 8 mg/L or meropenem MIC ≥ 8 mg/L. The data were analyzed by WHONET 5.6 software. Results Polymyxin B showed the highest activity against the A. baurnctnnil strains with decreased susceptihility or nonsuscepti-bility to carbapenems. All the strains were susceptible to poiymyxin B in vitro. Both MIC50 and MIC90 values were 1 mg/L.Tigecycline and minocycline could inhibit about 80% of the A. baumannii strains with decreased susceptibility to carbapenems. The MIC50/MIC90 ratio was 4/8 mg/L and 8/ 16mg/L, respectively. About 95% of the carbapenem-non-susceptible A. baumannii strains were susceptible or inter-mediate to tigecycline and minocycline. The MICso/MICgo ratio was 4/4 mg/L and 4/8 mg/L. Conclusions Polymyxin B, tigecycline and minocycline have relatively higher antibac-terial activity against the A. baumannii strains with de-creased susceptibility or nonsusceptibility to carbapenems.