全国碳青霉烯类耐药肺炎克雷伯菌对抗菌药物的敏感性、耐药机制和分子特征研究

National study on the antimicrobial susceptibility,resistance mechanisms,and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae

目的了解全国临床分离碳青霉烯类耐药肺炎克雷伯菌对抗菌药物的敏感性、耐药机制和分子特征。方法收集自我国31个省、市和自治区151所医疗机构2021年1—6月临床分离的碳青霉烯类耐药肺炎克雷伯菌,按区域统一运送至3个中心实验室。中心实验室按照统一的实验方案进行菌种复核鉴定,肉汤微量稀释法测定碳青霉烯类耐药肺炎克雷伯菌(CRKP)对抗菌药物的敏感性,所有菌株进行全基因组测序,分析菌株产生的碳青霉烯酶基因和多位点序列分型。结果共收集CRKP菌株4314株,CRKP57.7%(2396/4152)分离自呼吸道标本,其次为泌尿道标本(12.3%,510/4152)和血液标本(10.40%,432/4152)。药敏试验结果显示,氨曲南-阿维巴坦、黏菌素E、多黏菌素B和替加环素对CRKP具有高度抗菌活性(敏感率90.3%~96.4%)。头孢他啶-阿维巴坦及亚胺培南-瑞来巴坦在成人分离株中的敏感率高于儿童[分别为88.9%(3399/3822)和75.9%(2902/3822),51.4%(253/492)和50.4%(248/492)],而阿米卡星及复方磺胺甲基异噁唑在儿童分离株中的敏感率更高(65.2%,321/492和65.2%,321/492比25.5%,975/3822和36.8%,1407/3822)。KPC-2基因(85.9%,3705/4314)仍是我国CRKP中主要流行的碳青霉烯酶基因类型,其次为NDM(7.8%,336/4314)及OXA-48-like(1.3%,56/4314)基因。此外,部分菌株携带KPC-3、KPC-12、KPC-21、KPC-33和KPC-71等基因。虽然产KPC-2是成人与儿童分离CRKP的主要耐药机制,但检出率差别大,分别为90.2%(3447/3822)和52.2%(257/492),儿童患者中CRKP携带NDM基因的比例明显高于成人,分别为41.9%(206/492)和3.4%(130/3822)。多位点序列分型结果显示,我国临床分离的CRKP仍以ST11克隆型流行为主。结论不同省市之间分离CRKP的耐药机制和多位点序列分型有所差异。

Objective This study aims to evaluate the susceptibility,resistance mechanisms,and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae(CRKP)strains clinically isolated across various regions in the country with respect to antimicrobial drugs.Methods From January to June 2021,CRKP strains were collected from 151 medical institutions across 31 provinces,municipalities,and autonomous regions.These samples were transported to three central laboratories,divided by region.Each laboratory performed strain rechecking and identification based on a standardized experimental protocol.The broth microdilution method was employed to determine the susceptibility of CRKP strains to various antibacterial drugs.All strains were subjected to whole-genome sequencing and analysis,including the identification of carbapenemase genes and multilocus sequence typing.Results A total of 4314 CRKP strains were collected.Of these,57.7%(2396/4152)were isolated from respiratory tract specimens,12.3%(510/4152)from urinary tract specimens,and 10.4%(432/4152)from blood specimens.Susceptibility testing revealed that aztreonam-avibactam,colistin E,polymyxin B,and tigecycline demonstrated high antibacterial activity against CRKP,with susceptibility ranging from 90.3%to 96.4%.The susceptibility rates of ceftazidime-avibactam and imipenem-relebactam were notably higher in adult isolates(88.9%,3399 out of 3822,and 75.9%,2902 out of 3822)compared to children(51.4%,253 out of 492 and 50.4%,248 out of 492,respectively).Conversely,pediatric isolates showed higher susceptibility rates to amikacin and trimethoprim-sulfamethoxazole,at 65.2%each,compared to 25.5%and 36.8%among adult isolates.The KPC-2 gene predominated in 85.9%(3705/4314)of CRKP strains,followed by NDM and OXA-48-like genes at 7.8%(336/4314)and 1.3%(56/4314),respectively.Other genes identified included KPC-3,KPC-12,KPC-21,KPC-33,and KPC-71.Although KPC-2 was the primary resistance mechanism in both adults and children,detection rates varied significantly between these groups,at 90.2%(3447/3822)and 52.2%(257/492),respectively.Pediatric patients had a notably higher proportion of NDM genes,at 41.9%(206/492),compared to 3.4%in adults(130/3822).Multilocus sequence typing indicated that the ST11 sequence type remains the dominant strain among clinically isolated CRKP in the country.Conclusion There are notable regional differences in the resistance mechanisms and multilocus sequence typing of CRKP isolates across the country,underscoring the need for targeted approaches in managing infections caused by this pathogen.