血流感染病原菌的分布与耐药性分析

Distribution and antimicrobial susceptibility profile of the pathogens isolated from bloodstream infections

目的了解上海长海医院血流感染患者的病原菌分布及其对抗菌药物的耐药性,为临床合理用药提供依据。方法采用自动化仪器法和纸片扩散法(K-B法)对分离于2013年1月至2014年12月的菌株进行药物敏感性试验,参照2014版CLSI M100-S24标准判断药敏结果,替加环素的判读参照FDA标准,头孢哌酮-舒巴坦的判读参照头孢哌酮标准(2014年CLSI M100-S24)。结果从血流感染患者中共分离出非重复细菌1 048株,排名前3位的为大肠埃希菌(29.5%)、凝固酶阴性葡萄球菌(15.8%)和肺炎克雷伯菌(13.8%)。细菌总数位于前5位的科室分别为消化内科、血液内科、普外科、泌尿外科和感染科。不同科室分离出的细菌种类和数目不同。药敏结果显示,产超广谱β内酰胺酶(ESBL)的大肠埃希菌和肺炎克雷伯菌分别为63.8%和38.6%,耐甲氧西林凝固酶阴性葡萄球菌占该菌总数的77.6%。泌尿外科分离的大肠埃希菌对头孢菌素耐药率高于总体水平,而消化内科分离的大肠埃希菌对β内酰胺类-酶抑制剂复合制剂和碳青霉烯类抗生素的耐药率高于总体水平和其他科室。血液内科、泌尿外科和神经外科分离的凝固酶阴性葡萄球菌对甲氧西林的耐药率较高,神经外科分离菌耐药率更为100%。烧伤监护室的肺炎克雷伯菌对所有检测抗菌药物的耐药率均高于总体水平,消化内科的肺炎克雷伯菌对碳青霉烯类和替加环素的耐药率高于总体水平。结论不同科室分离出的血流感染细菌分布及其对常用抗菌药物的耐药性呈现不同特点,应加强监测各重点病区的病原菌分布及其耐药性,以指导抗生素的合理应用。

Objective To investigate the distribution and antimicrobial susceptibility of the bacteria isolated from bloodstream infections during 2013-2014 in Changhai Hospital for rational use of antibacterial agents. Methods The bacterial strains from blood samples were collected during the period from January 2013 through December 2014, and subjected to antimicrobial susceptibility testing by using automated system or Kirby-Bauer method. The results were interpreted according to CLSI M100-S24 breakpoints or FDA breakpoints. The data were analyzed by WHONET 5.6 software. Results A total of 1 048 nonduplicate isolates were collected, of which Escherichia coli, coagulase-negative Staphylococcus （CNS） and Klebsiella pneumoniae accounted for 29.5%, 15.8% and 13.8%, respectively. Gastroenterology, Hematology, General surgery, Urology and Department of Infectious Diseases are the top 5 departments according to their total number of bacterial isolates. The results of antimicrobial susceptibility testing showed thatESBLs-producing E. coli and K. pneumoniae accounted for 63.8% and 38.6%, respectively. The prevalence of methicillin- resistant CNS （MRCNS） was 77.6%. The E. coli strains isolated from Urology showed higher resistance rates to cephalosporins than the total E. coli strains, while the E. coli strains isolated from Gastroenterology showed higher resistance rates to beta- lactam/beta-lactamase inhibitor combinations and carbapenemsthan the total E. coli strains. Higher prevalence of MRCNS was found in departments of Hematology, Urology and Neurosurgery. All the CNS strains isolated from Neurosurgery were resistant to methicillin. The K. pneumoniae strains isolated from Burn ICU had higher resistance rates to all the antibacterial agents tested than the total K. pneumoniae strains, while the K. pneumoniae strains isolated from Gastroenterology showed higher resistance rates to carbapenems and tigecycline than the total K. pneumoniae strains. Conclusions The pathogenic bacteria isolated from bloodstream infections vary with departments in terms of species distribution and antimicrobial susceptibility profile. It is necessary to strengthen the surveillance of antimicrobial resistance in hospital for rational use of antibiotics.