Detection of Typhoidal and Paratyphoidal Salmonella in Blood by Real-time Polymerase Chain Reaction.
Clin Infect Dis
; 61 Suppl 4: S241-50, 2015 Nov 01.
Article
em En
| MEDLINE
| ID: mdl-26449938
ABSTRACT
BACKGROUND:
The gold standard for diagnosis of enteric fever caused by Salmonella Typhi or Salmonella Paratyphi A or B is bone marrow culture. However, because bone marrow aspiration is highly invasive, many hospitals and large health centers perform blood culture instead. As blood culture has several limitations, there is a need for novel typhoid diagnostics with improved sensitivity and more rapid time to detection.METHODS:
We developed a clyA-based real-time polymerase chain reaction (qPCR) method to detect Salmonella Typhi and Salmonella Paratyphi A simultaneously in blood. The sensitivity and specificity of this probeset was first evaluated in vitro in the laboratory and then in a typhoid-endemic population, in Karachi, Pakistan, and in healthy US volunteers.RESULTS:
We optimized a DNA extraction and real-time PCR-based method that could reliably detect 1 colony-forming unit/mL of Salmonella Typhi. The probe set was able to detect clinical Salmonella Typhi and Salmonella Paratyphi A strains and also diarrheagenic Escherichia coli, but not invasive E. coli or other invasive bacteria. In the field, the clyA qPCR diagnostic was 40% as sensitive as blood culture. However, when qPCR-positive specimens were considered to be true positives, blood culture only exhibited 28.57% sensitivity. Specificity was ≥90% for all comparisons and in the healthy US volunteers. qPCR was significantly faster than blood culture in terms of detection of typhoid and paratyphoid.CONCLUSIONS:
Based on lessons learned, we recommend that future field trials of this and other novel diagnostics that detect typhoidal and nontyphoidal Salmonella employ multiple methodologies to define a "positive" sample.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Salmonella paratyphi A
/
Salmonella typhi
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Febre Tifoide
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Febre Paratifoide
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Reação em Cadeia da Polimerase em Tempo Real
Tipo de estudo:
Diagnostic_studies
/
Evaluation_studies
Limite:
Adolescent
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Child
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Child, preschool
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Female
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Humans
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Male
País/Região como assunto:
Asia
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article