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目的研究荚膜多糖分型K1型肺炎克雷伯菌的毒力基因及其分子分型情况。方法收集2013年3—12月期间浙江大学医学院附属第二医院健康体检中心429份健康体检者粪便标本,按不同年龄组计算肺炎克雷伯菌肠道分离率;“拉丝”试验检测高产黏液菌株;聚合酶链反应(PCR)扩增K1、K2、K5、K20、K54、K57、rmp A、mag A和wca G;K-B纸片法检测K1型菌株药物敏感性;采用多位点序列分型(MLST)对K1型肺炎克雷伯菌进行分型。结果粪便标本肺炎克雷伯菌分离率为22.61%。97株肺炎克雷伯菌中“拉丝”阳性率为39.18%。共检测到11株携带K1毒力基因的肺炎克雷伯菌,4株同时携带mag A、wca G和rmp A,9株同时携带wca G和rmp A。<12岁组中未发现毒力基因存在。药敏结果显示K1型菌株除对氨苄西林耐药以外,对碳青霉烯类、喹诺酮类和头孢菌素类等抗生素均敏感。11株K1型菌株中有7株“拉丝”试验阳性。K1型菌株MLST分型结果,除1株为ST600外,其他均为ST23。结论粪便中分离的K1型肺炎克雷伯菌往往同时携带毒力基因rmp A、mag A和wca G,对临床常用抗菌药物敏感,ST23为其主要的临床流行株。
Objective To study the virulence genes and molecular typing of capsular polysaccharides in K1 pneumoniae Klebsiella pneumoniae. Methods Stool samples of 429 healthy subjects in the Second Affiliated Hospital of Zhejiang University from March 2013 to December 2013 were collected, and the intestinal separation rate of Klebsiella pneumoniae was calculated according to different age groups. The “Brushed” test K1, K2, K5, K20, K54, K57, rmp A, mag A and wca G were amplified by polymerase chain reaction (PCR); drug sensitivity of K1 strain was detected by KB disk method; Sequence typing (MLST) was used to classify Klebsiella pneumoniae K1. Results Staphylococcus aureus Klebsiella pneumoniae isolated rate was 22.61%. 97 strains of Klebsiella pneumoniae “drawing ” positive rate was 39.18%. Eleven strains of Klebsiella pneumoniae carrying K1 virulence genes were detected. Four strains carrying mag A, wca G and rmp A simultaneously and 9 strains carrying wca G and rmp A simultaneously. No virulence genes were found in the 12-year-old group. Susceptibility results showed that K1 strains were susceptible to antibiotics such as carbapenems, quinolones and cephalosporins in addition to ampicillin resistance. Seven out of 11 strains of type K1 were positive for “drawing” test. K1 strain MLST typing results, in addition to a ST600, the other are ST23. Conclusion Klebsiella pneumoniae K1 isolated from feces tend to carry virulence genes rmp A, mag A and wca G at the same time, which are sensitive to the commonly used antibiotics in clinical practice. ST23 is the main clinical epidemic strain.