title: Diagnosing Salmonella enterica Serovar Typhi Infections by Polymerase Chain Reaction Using EDTA Blood Samples of Febrile Patients From Burkina Faso.
abstract: BACKGROUND
  Globally, there are an estimated 22 million cases of Salmonella enterica serovar Typhi infection each year. However, this figure is likely to be an underestimate due to the low sensitivity of blood culture in S. Typhi diagnosis. The aim of this study was to diagnose S. Typhi by conventional polymerase chain reaction (PCR) using patient's blood preserved with ethylenediamine tetraacetic acid (EDTA).
  
  
  METHODS
  From April 2012 to September 2013, typhoid fever surveillance was conducted in Polesgo and Nioko, 2 dry slum areas in Ouagadougou, Burkina Faso. Blood culture was performed for febrile patients using an automated blood culture system. Additional blood was collected in EDTA tubes from those patients and preserved at -80°C. DNA was extracted from EDTA blood and PCR was performed to identify presence of S. Typhi. Randomly selected PCR products were further sequenced to identify S. Typhi-specific amplicons.
  
  
  RESULTS
  Of 1674 patients, S. Typhi was isolated from 18 (1.1%) individuals by blood culture. EDTA blood was collected from 1578 patients, of which 298 EDTA samples were tested by PCR. Salmonella Typhi-specific DNA was identified in 44 (14.8%) samples. The sensitivity of S. Typhi-specific PCR from EDTA blood was 89% (74%-100%) among the blood culture-positive cases. Sixteen S. Typhi-positive PCR products were sequenced, and 13 retrieved the sequence of a S. Typhi-specific amplicon.
  
  
  CONCLUSIONS
  These findings suggest that blood culture-based diagnoses of S. Typhi underestimate the burden of typhoid fever in Burkina Faso. PCR could be considered as an alternative method for the identification and diagnosis of S. Typhi in blood samples.
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine German Center for Infection Research, partner site Hamburg-Borstel-Lübeck, Germany.
authors.forename: Hassan M
authors.initials: HM
authors.lastname: Al-Emran
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hahn
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Jana
authors.initials: J
authors.lastname: Baum
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Ligia Maria
authors.initials: LM
authors.lastname: Cruz Espinoza
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Jessica
authors.initials: J
authors.lastname: Deerin
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Justin
authors.initials: J
authors.lastname: Im
authors.affiliation: Ministry of Health, Ouagadougou.
authors.forename: Samuel
authors.initials: S
authors.lastname: Ibrango
authors.affiliation: Institut Supérieur des Sciences de la Population, University of Ouagadougou, Burkina Faso.
authors.forename: Leon Parfait
authors.initials: LP
authors.lastname: Kabore
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Vera
authors.initials: V
authors.lastname: von Kalckreuth
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Frank
authors.initials: F
authors.lastname: Konings
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Florian
authors.initials: F
authors.lastname: Marks
authors.affiliation: Institut Supérieur des Sciences de la Population, University of Ouagadougou, Burkina Faso.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Sampo
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Ursula
authors.initials: U
authors.lastname: Panzner
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Se Eun
authors.initials: SE
authors.lastname: Park
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Gi Deok
authors.initials: GD
authors.lastname: Pak
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea Institute of Medical Microbiology, University of Cologne.
authors.forename: Heidi
authors.initials: H
authors.lastname: Schütt-Gerowitt
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea Department of Medicine, University Medical Center Hamburg-Eppendorf, Germany.
authors.forename: Christof David
authors.initials: CD
authors.lastname: Vinnemeier
authors.affiliation: International Vaccine Institute, Seoul, Republic of Korea.
authors.forename: Michelle
authors.initials: M
authors.lastname: Warren
authors.affiliation: Institut Supérieur des Sciences de la Population, University of Ouagadougou, Burkina Faso.
authors.forename: Abdramane Bassiahi
authors.initials: AB
authors.lastname: Soura
mesh_terms: D000293:Adolescent; D000328:Adult; D016470:Bacteremia / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology; D002050:Burkina Faso; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004269:DNA, Bacterial / Q000097:blood*; D004492:Edetic Acid; D005260:Female; D005334:Fever / Q000209:etiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D058889:Molecular Typing / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods*; D062486:Public Health Surveillance; D012485:Salmonella typhi / Q000235:genetics*; D014435:Typhoid Fever / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D004492:Edetic Acid
keywords: Burkina Faso; PCR; Salmonella; Typhi; sensitivity