title: Evaluation of TUBEX-TF and OnSite Typhoid IgG/IgM Combo rapid tests to detect Salmonella enterica serovar Typhi infection during a typhoid outbreak in Harare, Zimbabwe.
abstract: BACKGROUND
  Salmonella enterica serovar Typhi, the causative agent of typhoid, is endemic in most parts of the world especially in Africa. Reliable and rapid diagnosis of the bacterium is therefore critical for confirmation of all suspected typhoid cases. In many parts of Zimbabwe, laboratory capacity to isolate the microorganism by culture method as a way of diagnosis has limitations. In this study, two rapid serological kits, TUBEX-TF and OnSite Typhoid IgG/IgM Combo, were evaluated for possible expeditious diagnosis of Salmonella enterica serovar Typhi infection during a typhoid outbreak in Zimbabwe.
  
  
  METHODS
  Blood was collected from patients with clinical signs and symptoms of typhoid in Harare, Zimbabwe during an outbreak. The standard culture method was used to diagnose the disease. Two rapid kits, the TUBEX-TF and OnSite Typhoid IgG/IgM Combo, were also used in parallel to diagnose typhoid according to manufacturers' instructions. The diagnostic accuracy of the two kits was evaluated using the culture method as the gold standard.
  
  
  RESULTS
  From all the cases diagnosed by the blood culture (n = 136), we enrolled 131 patients for the TUBEX-TF and 136 for the OnSite Typhoid IgG/IgM Combo tests. With the culture method as a reference standard, we found that TUBEX-TF test was 100% sensitive and 94.12% specific, with 63.16% positive and 100% negative predictive values (NPVs) and the OnSite Typhoid IgG/IgM Combo test was 100% sensitive and 94.35% specific, with 63.16% positive and 100% NPVs.
  
  
  CONCLUSIONS
  Our results indicated that TUBEX-TF and OnSite Typhoid IgG/IgM Combo rapid tests were useful tools for the rapid diagnosis of Salmonella enterica serovar Typhi infection during typhoid outbreaks in Zimbabwe. The tests performed very well in laboratory evaluations of blood culture-confirmed typhoid cases in Harare, Zimbabwe.
authors.affiliation: National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe. tarupiwaa@nmrl.org.zw.
authors.forename: Andrew
authors.initials: A
authors.lastname: Tarupiwa
authors.affiliation: National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe. Taperas@nmrl.org.zw.
authors.forename: Simba
authors.initials: S
authors.lastname: Tapera
authors.affiliation: National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe. zinyoweras@nmrl.org.zw.
authors.forename: Sekesai
authors.initials: S
authors.lastname: Mtapuri-Zinyowera
authors.affiliation: National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe. gumbop@nmrl.org.zw.
authors.forename: Peter
authors.initials: P
authors.lastname: Gumbo
authors.affiliation: Department of Medical Microbiology, College of Health Sciences, University of Zimbabwe, P.O. Box A178, Avondale, Zimbabwe. vruhanya@gmail.com.
authors.forename: Vurayai
authors.initials: V
authors.lastname: Ruhanya
authors.affiliation: National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe. mugabem@nmrl.org.zw.
authors.forename: Muchaneta
authors.initials: M
authors.lastname: Gudza-Mugabe
authors.affiliation: National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe. majurun@nmrl.org.zw.
authors.forename: Ngoni Xmas
authors.initials: NX
authors.lastname: Majuru
authors.affiliation: Department of Medical Microbiology, College of Health Sciences, University of Zimbabwe, P.O. Box A178, Avondale, Zimbabwe. Nyasha.Chinombe@gmail.com.
authors.forename: Nyasha
authors.initials: N
authors.lastname: Chin'ombe
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood*; D008297:Male; D011933:Reagent Kits, Diagnostic; D012485:Salmonella typhi / Q000276:immunology; D012680:Sensitivity and Specificity; D014435:Typhoid Fever / Q000175:diagnosis* / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology; D015030:Zimbabwe / Q000453:epidemiology
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011933:Reagent Kits, Diagnostic