Epidemiology investigation of carbapenems-resistant Klebsiella pneumoniae in burn care unit
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摘要:
目的 研究烧伤监护室抗碳青霉烯类抗生素肺炎克雷伯菌(CRKP)的耐药机制及基因分型。 方法 收集陆军军医大学(第三军医大学)第一附属医院全军烧伤研究所(以下称笔者科室)2017年1—12月烧伤监护室初次分离的来自22例烧伤患者[男20例、女2例,年龄(42±16)岁]的27株CRKP。菌株鉴定后统计检出月份和来源样本分布。选用15种抗生素行药物敏感试验。采用PCR法检测耐药基因,采用脉冲场凝胶电泳(PFGE)和多位点序列分型(MLST)分析菌株基因分型。 结果 (1)2017年全年中,笔者单位8月(8株)、9月(6株)和10月(5株)CRKP检出数量居多,1、3、6、11、12月没有CRKP检出,其中病床单元的5株CRKP分别在8月检出2株、9月检出1株、10月检出2株。(2)27株CRKP中40.7%(11/27)来自血液样本,18.5%(5/27)来自创面分泌物样本,11.1%(3/27)来自深静脉导管样本,7.4%(2/27)来自痰液样本,3.7%(1/27)来自尿液样本,18.5%(5/27)来自病床单元样本。(3)27株CRKP对头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、头孢唑林、头孢曲松、头孢吡肟、厄他培南和复方磺胺甲唑7种抗生素的耐药率均为100.0%,对替加环素100.0%敏感,对其余7种抗生素的耐药率均高于81.0%。(4)27株CRKP的
bla CTX-M-10、
bla SHV、
bla TEM、
bla CTX-M-14、
bla ACT、
bla KPC基因的检出率均>92.5%。(5)经PFGE检测,27株CRKP被分为A、A1、A2、B、C和D共6个型别,其中A型检出率为37.0%(10/27),集中在2、5、9月检出;C型检出率为48.1%(13/27),集中在7、8、10月检出;A1型、A2型、B型和D型的检出率均为3.7%(1/27),为散在检出。经MLST检测,27株CRKP共获得6个ST型,其中ST11型检出率最高,为74.1%(20/27),集中在8—10月检出;ST395、ST2230、ST215、ST260和STnew型检出率为3.7%(1/27)~7.4%(2/27),为散在检出。 结论 笔者科室烧伤监护室分离的CRKP以血液来源为主,所有CRKP菌株均显示高耐药率且耐药机制复杂,A型、C型和ST11型CRKP检出率高且在病房中引起了小范围的暴发流行,应引起临床治疗及感染控制的高度重视。
Abstract:Objective To explore the resistance mechanism and gene type of carbapenems-resistant
Klebsiella pneumoniae (CRKP) in burn care unit. Methods A total of 27 CRKP strains were primarily isolated from 22 patients [20 males, 2 females, aged (42±16) years] admitted to burn care unit of Institute of Burn Research of the First Affiliated Hospital of Army Medical University (the Third Military Medical University, hereinafter referred to as our department) from January to December 2017. After identification of bacteria, the months of detection and distribution of sample source were analyzed. Drug resistance tests of 15 antibiotics were conducted. Polymerase chain reaction was used to detect the drug resistant genes. Pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were used to analyze the gene type of strains. Results (1) During the whole year of 2017, CRKP strains were mostly detected in August (8 strains), September (6 strains), and October (5 strains), with no CRKP in January, March, June, November, and December. Five strains from bed units were detected in August (2 strains), September (1 strain), and October (2 strains). (2) Twenty-seven CRKP strains were derived from blood samples (40.7%, 11/27), wound exudate samples (18.5%, 5/27), deep vein catheter samples (11.1%, 3/27), sputum samples (7.4%, 2/27), urine samples (3.7%, 1/27), and bed unit samples (18.5%, 5/27). (3) The 27 CRKP strains were detected with drug-resistance rates of 100.0% to 7 antibiotics including cefoperazone/sulbactam, piperacillin/tazobactam, cefazolin, ceftriaxone, cefepime, ertapenem, and compound sulfamethoxazole, no drug-resistance to tigecycline, with drug-resistance rates higher than 81.0% to the rest 7 antibiotics. (4) Detection rates for resistance gene
bla CTX-M-10,
bla SHV,
bla TEM,
bla CTX-M-14,
bla ACT, and
bla KPC were all above 92.5%. (5) According to PFGE, the 27 CRKP strains had 6 types (A, A1, A2, B, C, and D). Strains of type A were mainly detected in February, May, and September, with detection rate of 37.0% (10/27). Strains of type C were mainly detected in July, August, and October, with detection rate of 48.1% (13/27). Strains of types A1, A2, B, and D were scatteredly detected, with detection rate of 3.7% (1/27) respectively. According to MLST, the 27 CRKP strains had 6 STs. ST11 was the most frequent type, accounting for 74.1% (20/27), which was detected in August to October. The detection rate of ST395, ST2230, ST215, ST260, and STnew ranged from 3.7%(1/27) to 7.4%(2/27), and the strains were scatteredly detected. Conclusions The main source of CRKP from burn care unit of our department was bloodstream. All the CRKP strains showed high drug-resistance rate and complicated resistance mechanism. There were small scale outbreaks caused by CRKP of type A, type C, and ST11, which should be paid more attention to in clinical treatment and infection control.
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Key words:
- Burns /
- Klebsiella pneumoniae /
- Drug resistance /
- Cross infection /
- Carbapenems
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