title: [Establishment of a triplex real-time PCR for the detection of cholera toxin gene ctx and heat labile enterotoxin gene elt].
abstract: OBJECTIVE
  To establish a triplex TaqMan real-time PCR system containing internal amplification control (IAC) to detect cholera toxin gene ctxA and enterotoxigenic Escherichia coli (ETEC)heat-labile enterotoxin gene elt.
  
  
  METHODS
  Primers and probes were designed based on the sequences of ctxA, elt and IAC. Both sensitivity and specificity were analyzed and interactions between different reactions were evaluated.
  
  
  RESULTS
  This system showed that the sensitivity of ctxA was 94 copies/reaction while the elt 79 copies/reaction and the amplification efficiency were 94.7% and 98.1%, respectively. Under the ratio of copy numbers on gene ctxA to elt as between 1 : 1-1 : 10, when both targets were detected, with impact was less on each other. However, when the amount of elt or ctxA was 100 times of IAC, the amplification of IAC was significantly inhibited.
  
  
  CONCLUSIONS
  This system showed both satisfactory sensitivity and specificity, thus could be used to detect pathogenic bacteria in diarrhea stools. The detection of IAC could prompt the presence of PCR inhibitors in samples being tested.
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China. Email: zhangjingyun@icdc.cn.
authors.forename: Jingyun
authors.initials: J
authors.lastname: Zhang
mesh_terms: D002772:Cholera Toxin / Q000235:genetics*; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics; D004768:Enterotoxins / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D004768:Enterotoxins; D002772:Cholera Toxin