title: Early diagnosis of typhoid fever by nested PCR for flagellin gene of Salmonella enterica serotype Typhi.
abstract: OBJECTIVE
  Typhoid fever caused by Salmonella Typhi continues to be a major health problem in spite of the use of antibiotics and the development of newer antibacterial drugs. Inability to make an early laboratory diagnosis and resort to empirical therapy, often lead to increased morbidity and mortality in cases of typhoid fever. This study was aimed to optimize a nested PCR for early diagnosis of typhoid fever and using it as a diagnostic tool in culture negative cases of suspected typhoid fever.
  
  
  METHODS
  Eighty patients with clinical diagnosis of typhoid fever and 40 controls were included in the study. The blood samples collected were subjected to culture, Widal and nested PCR targeting the flagellin gene of S. Typhi.
  
  
  RESULTS
  The sensitivity of PCR on blood was found to be 100 per cent whereas the specificity was 76.9 per cent. The positive predictive value (PPV) of PCR was calculated to be 76.9 per cent with an accuracy of 86 per cent. None of the 40 control samples gave a positive PCR.
  
  
  CONCLUSIONS
  Due to its high sensitivity and specificity nested PCR can be used as a useful tool to diagnose clinically suspected, culture negative cases of typhoid fever.
authors.affiliation: Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education & Research, Puducherry, India.
authors.forename: S
authors.initials: S
authors.lastname: Khan
authors.forename: B N
authors.initials: BN
authors.lastname: Harish
authors.forename: G A
authors.initials: GA
authors.lastname: Menezes
authors.forename: N S
authors.initials: NS
authors.lastname: Acharya
authors.forename: S C
authors.initials: SC
authors.lastname: Parija
mesh_terms: D001483:Base Sequence; D016022:Case-Control Studies; D017931:DNA Primers; D042241:Early Diagnosis; D005408:Flagellin / Q000235:genetics*; D005798:Genes, Bacterial; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D019779:Salmonella enterica / Q000235:genetics*; D012680:Sensitivity and Specificity; D014435:Typhoid Fever / Q000175:diagnosis*
chemical_list: D017931:DNA Primers; D005408:Flagellin