目的 通过高通量测序法对多重耐药大肠埃希菌HX43进行耐药分子机制的研究。方法 用Illumina Miseq平台对HX43进行高通量测序,用Edena、RAST、ResFinder、MLST和BLAST等生物信息学工具或数据库进行数据分析,获得耐药基因相关序列数据。结果 HX43对多种临床常用抗生素均不敏感,仅对碳氢霉烯类药物敏感。对高通量测序数据的分析研究发现,该菌存在多种耐药基因,包括β-内酰胺类耐药基因3个(blaCMY-42、blaCTX-M-14和blaOXA-30),氨基糖苷类耐药基因5个(aac(3)-IIa、aadA5、 strA、 strB和aac(6′)-Ib-cr),喹诺酮类耐药基因1个(aac(6′)-Ib-cr),磺胺及甲氧苄啶类耐药基因3个(sul1、sul2和dfrA17),四环素耐药基因1个(tet(B)),氯霉素耐药基因2个(catB3和cmlA1),大环内酯类耐药基因2个(erm(B)和mph(A))。对包含blaCMY-42的contigs进行分析,发现该基因与ISEcp1插入序列、blc和sugE等基因相关联。质粒分型发现HX43携带5种不相容群的质粒。多位点序列分型(MLST)分析发现HX43属于ST3835,为国内外较少见的序列型。结论 高通量测序技术可准确获得临床菌株抗生素耐药的相关基因信息,为临床抗菌治疗提供重要的实验室数据支持。
Objective To investigate the molecular resistance mechanism of Escherichia coli HX43 by high-throughput sequencing. Methods HX43 was sequenced by the Illumina Miseq platform, and sequencing data were analyzed by the Edena, RAST, ResFinder, MLST and BLAST softwares and databases. Results HX43 was resistant to most common clinical antibiotics except carbapenems. Analysis of data revealed resistance genes to β-lactams (blaCMY-42, blaCTX-M-14 and blaOXA-30), aminoglycosides (aac(3)-IIa, aadA5, strA, strB and aac(6′)-Ib-cr), quinolones (aac(6′)-Ib-cr), trimethoprim/sulfonamides(sul1, sul2 and dfrA17), tetracyclines (tet(B)), chloramphenicol (catB3 and cmlA1), macrolides(erm(B) and mph(A)). Sequence analysis of the contig containing blaCMY-42 identified correlations of the gene with ISEcp1 insertion sequences, blc and sugE genes. Plasmid typing identified 5 plasmid incompatibility groups in HX43. MLST analysis found that HX43 belonged to ST3835, a relatively rare sequence type in the world. Conclusion Information of resistance genes can be obtained by high-throughput sequencing, which provides important experimental data for clinical antimicrobial treatment.
目的 统计分析2011—2014年我院分离的肠杆菌科细菌数据,探讨耐碳青霉烯肠杆菌科细菌(CRE)的流行特征。方法 收集肠杆菌科细菌,根据药敏结果筛选出CRE菌株,并对相关临床资料进行统计分析。结果 共分离得到CRE菌株187株,标本来源依次为尿液(32.6%)、痰液(28.9%)和血液(10.7%)。从科室分布来看,39.0%的菌株来自重症监护室病区,23.0%的菌株来自泌尿外科病区,在其它病区呈散发分布。菌株的种属分布方面,肺炎克雷伯菌的比例为39.6%, 大肠埃希菌的比例为20.9%;从病人年龄构成来看,50岁以上高龄患者的分离比例达74.4%。CRE的分离数目随年份的递增而不断升高。结论 耐碳青霉烯肠杆菌科细菌的流行率呈现逐年递增的趋势,临床应合理使用相关抗生素,预防和控制CRE在医院环境中的流行。
Objective To investigate the epidemiological features of carbapenem resistant Enterobacteriaceae in a collection of clinical Enterobacteriaceae strains isolated during 2011-2014 from our hospital. Methods The Enterobacteriaceae strains were collected and CRE strains were screened by their resistance to carbapenems. Clinical information was analyzed to characterize the epidemiological traits of CRE strains. Results The total number of CRE isolates was 187. These CRE strains were isolated from various clinical specimens, including urine(32.6%), sputum (28.9%), blood (10.7%), and so on. These strains were frequently isolated from intensive care units (ICU) (39.0%) and department of Urology (23.0%). The most frequently isolated species were Klebsiella pneumoniae (39.6%), Escherichia coli (20.9%). The isolation rate is much higher in elderly patients more than 50 years old (74.4%). The percentage of CRE isolates were kept on increasing by years. Conclusion The prevalence carbapenem resistant Enterobacteriaceae in our hospital is increasing every year and it is important to prevent and control the transmission and outbreaks of CRE in the hospital by proper use of related antibiotics in clinical treatment.
目的 利用基质辅助激光解吸电离飞行时间质谱系统(VITEK-MS)对体液培养阳性瓶进行直接鉴定,探索快速诊断临床致病菌的新策略。方法 收集体液培养阳性瓶,不经琼脂平板培养,直接利用VITEK-MS进行鉴定,并与传统生化鉴定的方法进行比较分析。结果 50例体液培养阳性瓶中,传统细菌鉴定法检出47株阳性菌,3例阴性;而VITEK-MS直接鉴定法检出31株阳性菌,同样3例阴性。VITEK-MS直接鉴定法灵敏度达65.96%,特异度为100%,临床符合率为68%。鉴定时间从24小时缩短到2小时。结论 利用VITEK-MS质谱系统直接鉴定体液培养阳性标本中的病原菌,能有效缩短细菌鉴定时间,准确快速地诊断临床致病菌。
Objective To find a fast method for detection of pathogens in positive culture bottles by using the VITEK-MS system. Methods VITEK-MS microbial identification system was used to directly identify the bacteria in the positive culture bottles, without culture on agar plates. The identification results were further compared with those by the traditional biochemical identification. Results Forty-seven bacterial strains were identified by traditional biochemical methods among 50 positive culture bottles, and 3 of them were negative. Of these 50 samples, thirty-one bacterial strains were identified by VITEK-MS and 3 were also negative. The sensitivity and specificity for direct VITEK-MS identification were 65.96% and 100%, and the clinical coincidence rate was 68%. The turn around time for identification was reduced from 24 to 2 hours. Conclusion Direct identification of bacterial pathogens in positive culture bottles by VITEK-MS could reduce turn around time, and lead to accurate and fast diagnosis.
