携带新型金属β-内酰胺酶基因菌株在某患者体内播散及耐药研究

Drug resistance and dissemination of New Delhi metallo-β-lactamase 1 positive bacteria in a patient

目的 分析携带新型金属β-内酰胺酶（NDM-1）基因（blaNDM-1）菌株在患者不同部位间的播散情况和对环境的影响。方法 于2010年，在某51岁男性患者因车祸入院时及整个治疗过程中，采集患者的血液、尿液、痰液、粪便样本，同时对患者病房环境进行取样，按照临床微生物检验的常规操作进行碳青霉烯耐药菌株筛查和分离；利用VITEK微生物鉴定/药物敏感性分析仪和E-test试剂条对分离的耐药菌株进行种属鉴定和药物敏感性检测，利用PCR、PFGE及Sourthern杂交对菌株blaNDM-1进行检测及定位。结果 患者从10月1日入院到11月4日出院，在其血液、痰液、尿液、粪便及病房地面共分离到的9株菌株，血液样本分离到产酸克雷伯菌、植生拉乌尔菌和鲍曼不动杆菌，痰液样本中分离到肺炎克雷伯菌和鲍曼不动杆菌，尿液样本中分离到洛菲不动杆菌，粪便样本中分离到大肠杆菌，病房地面样本中分离到洛菲不动杆菌和不动杆菌属菌株，其中4株菌为blaNDM-1菌株，分别为从患者血液样本中分离的植生拉乌尔菌（RpNDM1），从患者粪便样本中分离到的大肠杆菌（EcNDM1），从病房地面分离的洛菲不动杆菌（AlDNM1）和不动杆菌属菌株（AsNDM1）；4株菌株均对哌拉西林、哌拉西林-他唑巴坦、头孢吡肟、头孢曲松、头孢他啶、亚胺培南、美罗培南、厄他培南耐药，且携带的blaNDM-1均位于质粒上。结论 blaNDM-1可以在短期内实现跨种属传播，在院内感染控制中应考虑blaNDM-1菌株在不同部位间传播的风险，加强对携带该菌株患者的粪便样本的处理。

Objective The aim of this work was to report the surveillance and dissemination of NDM-1 positive bacteria in a patient and ward environment.Methods In 2010, during the therapy for a 51 years old patient, clinical and environmental samples were collected for carbapenem resistant bacterial culture, according to the clinical microbiological examination. Strains identification and antibiotic susceptibility were tested by VITEK Compact 2 system and E-test. The blaNDM-1 was detected by PCR and analyzed by sequencing. Plasmids containing blaNDM-1 were submitted to PFGE-S1 and Southern hybridization.Results During hospitalization from October 1st to November 4th, nine strains were isolated from blood, sputum, urine, fecal, and ward ground samples. The Klebsiella oxytoca, Raoultella planticola, and Acinetobacter baumannii were isolated from blood sample. The Klebsiella pneumonia and Acinetobacter baumannii were isolated from sputum sample. An Acinetobacter lwoffii was isolated from urine sample. An Escherichia coli was isolated from fecal sample. And the Acinetobacter lwoffii and Acinetobacter spp. were isolated from ward ground. Four strains were NDM-1 positive, which were Raoultella planticola （RpNDM1） isolated from blood, Escherichia coli （EcNDM1） isolated from fecal, Acinetobacter lwoffii （AlDNM1） and Acinetobacter spp. （AsNDM1） isolated from ward ground. Four NDM-1 positive strains were resistant to Piperacillin, Piperacillin tazobactam, Cefepime, Ceftriaxone, Ceftazidime, Imipenem, Meropenem, and Ertapenem. Southern hybridization revealed that blaNDM-1 were all located on plasmids in the four positive strains.Conclusion blaNDM-1 can transfer rapidly among different species, resulting in difficult to control and prevent. While isolating patient who is carrying NDM-1 positive strains, more attention should be paid to the disposal of patient＇s excreta, especially stool, should be paid more attention.