耐碳青霉烯类肠杆菌属细菌的抗菌药物耐药性及氨曲南联合阿维巴坦体外杀菌试验研究

Study on antimicrobial resistance profile and in vitro bactericidal assays of aztreonam combined with avibactam for carbapenem-resistant Enterobacter spp.

目的调查耐碳青霉烯类肠杆菌属细菌(carbapenem-resistant Enterobacter spp.,CREn)的耐药情况以及氨曲南联合阿维巴坦对其的杀菌作用。方法对四川大学华西医院2016年-2021年自临床分离到的CREn菌株通过gyrB基因扩增测序鉴定菌种。汇总这些菌株的药物敏感性结果、标本类型和相关患者科室分布。选择多黏菌素耐药和中介菌株进行多黏菌素E和氨曲南联合阿维巴坦的杀菌试验。结果共纳入110株CREn临床菌株,最多的菌种为香坊肠杆菌(91株),占比最高的科室为重症监护病房(27.27%),呼吸道来源的标本占比超过40%。药物敏感性结果显示,所有CREn均对碳青霉烯类耐药,对多黏菌素的耐药率为23.64%,对氨曲南联合阿维巴坦的耐药率为0;其他抗菌药物中仅阿米卡星和替加环素的耐药率低于10%。时间-杀菌曲线显示,对于多黏菌素中介菌株,多黏菌素相比氨曲南联合阿维巴坦能在更短时间内达到杀菌效果;但无论菌株是否对多黏菌素耐药,2μg/mL的氨曲南联合阿维巴坦在24 h的杀菌率均能超过99%。结论CREn对临床常用的绝大多数抗菌药物耐药,但对氨曲南联合阿维巴坦保持敏感,且氨曲南联合阿维巴坦对其具有杀菌作用。

Objective To investigate antimicrobial resistance profiles of carbapenem-resistant Enterobacter spp.(CREn)and the bactericidal effects of aztreonam combined with avibactam.MethodsThe CREn strains isolated from the West China Hospital of Sichuan University between 2016 and 2021 were identified by gyrB gene amplification and subsequent sequencing.The drug sensitivity results,sample types and distribution of relevant patient departments of these strains were summarized.Colistin-resistant and-intermediate strains were selected to carry out the bactericidal test of colistin and aztreonam combined with avibactam.Results A total of 110 clinical strains of CREn were included.The most common strain was Enterobacter xiangfangensis(91 strains),the highest proportion was in the intensive care unit(27.27%),and the proportion of respiratory tract samples was more than 40%.The antimicrobial sensitivity results showed that CREns were all resistant to carbapenems,the resistance rate to colistin was 23.64%,and the resistance rate to aztreonam combined with avibactam was 0.Among other antimicrobial agents,the antimicrobial resistance rate of amikacin and tigecycline were less than 10%.The time-kill curve showed that for colistin-intermediate strains,colistin could achieve bactericidal effect in a shorter time than aztreonam combined with avibactam.However,whether the strain was resistant to colistin or not,the bactericidal rate of 2μg/mL aztreonam combined with avibactam in 24 hours could exceed 99%.Conclusion CREn is resistant to most commonly used clinical antibacterial drugs,but remains sensitive to aztreonam combined with avibactam,and aztreonam combined with avibactam has bactericidal effect on it.