1.Evaluation of Rapid Diagnostic
Tests for Typhoid Fever” J clin
microbial. 2004; 42:1885–89
EMAN ABD ELRAOUF AHMED
INTRODUCTION
Typhoid fever usually is caused by Salmonellae typhi bacteria.
Typhoid fever is contracted by the ingestion o...
Typhoid contamination
Typhoid fever is contracted by the ingestion of the bacteria in
contaminated food or water.
Patients...
diagnosis
Blood test
Bone marrow test
Stool culture test
Widal Test
Antigenic structure for Salmonella
Two sets of antigens
Detection by serotyping
1 Somatic or 0 Antigens contain long chain...
Immune response
statistics
In untreated patients mortality can
be up to 20 %
Salmonella enterica causes
approximately 16 million cases of
...
abstract
Samples were collected from 530 outpatients with axillary temperatures
of ≥37.5°C, and analysis was conducted on ...
Hypothesis and aim of the work
Use a suitable diagnostic tool
Methods (experimental design)
1-Participant recruitment and specimen
collection. Patient recruitment took place
at the Gor...
continue
Molecular detection. DNA extraction was conducted from
200 μl of whole blood using the Qiagen DNeasy blood and
ti...
. Negative and positive controls were included
in each run. A positive result was defined as
a sample having a cycle thres...
Figures and comment
statistics
Discussion and conclusions
demonstrates the value of using the molecular detection of S. Typhi
in blood when evaluating ra...
References:
http://www.ncbi.nlm.nih.gov/pmc/arti
/3491554cles/PMC
THANK you
Upcoming SlideShare
Loading in …5
×

Typhoid

641 views

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
641
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
25
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Typhoid

  1. 1. 1.Evaluation of Rapid Diagnostic Tests for Typhoid Fever” J clin microbial. 2004; 42:1885–89 EMAN ABD ELRAOUF AHMED
  2. 2. INTRODUCTION Typhoid fever usually is caused by Salmonellae typhi bacteria. Typhoid fever is contracted by the ingestion of contaminated food or water. Diagnosis of typhoid fever is made when the Salmonella bacteria is detected with a stool culture. Typhoid fever is treated with antibiotics. Typhoid fever symptoms are poor appetite, headaches, generalized aches and pains, fever, and lethargy. Approximately 3%-5% of patients become carriers of the bacteria after the acute illness.
  3. 3. Typhoid contamination Typhoid fever is contracted by the ingestion of the bacteria in contaminated food or water. Patients with acute illness can contaminate the surrounding water supply through stool, which contains a high concentration of the bacteria. Contamination of the water supply can, in turn, taint the food supply. About 3%-5% of patients become carriers of the bacteria after the acute illness. These patients can become long-term carriers of the bacteria. The bacteria multiplies in the gallbladder, bile ducts, or liver and passes into the bowel. The bacteria can survive for weeks in water or dried sewage. These chronic carriers may have no symptoms .
  4. 4. diagnosis Blood test Bone marrow test Stool culture test Widal Test
  5. 5. Antigenic structure for Salmonella Two sets of antigens Detection by serotyping 1 Somatic or 0 Antigens contain long chain polysaccharides ( LPS ) comprises of heat stable polysaccharide commonly. 2 Flagellar or H Antigens are strongly immunogenic and induces antibody formation rapidly and in high titers following infection or immunization. The flagellar antigen is of a dual nature, occurring in one of the two phases.
  6. 6. Immune response
  7. 7. statistics In untreated patients mortality can be up to 20 % Salmonella enterica causes approximately 16 million cases of typhoid fever worldwide, killing around 500,000 per year.
  8. 8. abstract Samples were collected from 530 outpatients with axillary temperatures of ≥37.5°C, and analysis was conducted on all malaria-negative samples (n = 500). A composite reference standard of blood culture and PCR was used, by which 47 participants (9.4%) were considered typhoid fever positive. The sensitivity and specificity of the Tubex (51.1% and 88.3%, respectively) and TyphiDot (70.0% and 80.1%, respectively) tests were not high enough to warrant their ongoing use in this setting; however, the sensitivity and specificity for the TR-02 prototype were promising (89.4% and 85.0%, respectively). An axillary temperature of ≥38.5°C correlated with typhoid fever (P = 0.014). With an appropriate diagnostic test, conducting typhoid fever diagnosis only on patients with high-grade fever could dramatically decrease the costs associated with diagnosis while having no detrimental impact on the ability to accurately diagnose the illness.
  9. 9. Hypothesis and aim of the work Use a suitable diagnostic tool
  10. 10. Methods (experimental design) 1-Participant recruitment and specimen collection. Patient recruitment took place at the Goroka General Hospital outpatient center and the Lopi Urban Clinic in Goroka, Eastern Highlands Province, Papua New Guinea. Febrile patients (axillary temperature, ≥37.5°C) who reported having fever for at least 2 days were invited to participate in the
  11. 11. continue Molecular detection. DNA extraction was conducted from 200 μl of whole blood using the Qiagen DNeasy blood and tissue extraction kit, according to the manufacturer's instructions for extraction from blood samples. The real-time PCR was conducted in a 20-μl reaction mix containing 2 μl of the DNA extract, 400 nM (each) ST5 and ST6A primers, 400 nM TaqMan probe ST7, 1× QuantiTect Mastermix (Qiagen), and nuclease-free water. All reactions were conducted on a Bio-Rad CFX-96 real-time system with the following cycling parameters: 50°C for 2 min, followed by 40 cycles of 94°C for 1 min and 60°C for 1-minute
  12. 12. . Negative and positive controls were included in each run. A positive result was defined as a sample having a cycle threshold (CT) between 16 and 40 using an autocalculated single-threshold baseline using the Bio-Rad CFX Manager software version 2.0. The specificity of this real-time PCR assay has been previously described, and it was found to be specific for S. Typhi.
  13. 13. Figures and comment
  14. 14. statistics
  15. 15. Discussion and conclusions demonstrates the value of using the molecular detection of S. Typhi in blood when evaluating rapid diagnostic tests. Despite bone marrow culture being the gold standard of typhoid diagnosis, blood culture is universally used as the reference standard when evaluating typhoid diagnostic tests. We have demonstrated a 2.1-fold increase in typhoid fever diagnosis when blood culture and real-time PCR detection were used, relative to blood culture alone. The correlation between typhoid fever and high-grade fever (axillary temperature of ≥38.5°C) may have important implications for typhoid fever diagnosis.
  16. 16. References: http://www.ncbi.nlm.nih.gov/pmc/arti /3491554cles/PMC
  17. 17. THANK you

×