Molecular analysis of isolates of Salmonella typhi obtained from fatal, mild and sporadic cases of typhoid fever
Molecular characterization of a total of 52 human isolates of Salmonella typhi from Papua New Guinea was performed by using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with three restriction endonucleases, XbaI (5*-TCTAGA-3*), AvrII (5*-CCTAGG-3*), and SpeI (5*-ACTAG...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | en |
| Published: |
American Society for Microbiology
1996
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| Subjects: | |
| Online Access: | http://eprints.um.edu.my/18588/1/J._Clin._Microbiol.-1996-Thong-1029-33.pdf http://eprints.um.edu.my/18588/ |
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| Summary: | Molecular characterization of a total of 52 human isolates of Salmonella typhi from Papua New Guinea was
performed by using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with three
restriction endonucleases, XbaI (5*-TCTAGA-3*), AvrII (5*-CCTAGG-3*), and SpeI (5*-ACTAGT-3*). Of the 52
isolates tested, 11 were obtained from patients with fatal typhoid fever and 41 were obtained from patients with
nonfatal disease. The 52 isolates showed limited genetic diversity as evidenced by only three different PFGE
patterns detected following digestion with XbaI (patterns X1 to X3; F [coefficient of similarity] 5 0.86 to 1.0),
four patterns detected following digestion with AvrII (patterns A1 to A4; F 5 0.78 to 1.0), and two patterns
detected following digestion with SpeI (patterns S1 and S2; F 5 0.97 to 1.0). Of the 52 isolates, 37 were phage
typed, and all belonged to phage type D2. All 11 isolates obtained from patients with fatal typhoid fever were
identical (F 5 1.0) and possessed the PFGE pattern combination X1S1A1, whereas the 41 isolates from
patients with nonfatal typhoid fever had various PFGE pattern combinations, the most common being X2S1A2
(39%), X1S1A1 (24%), and X1S1A2 (15%). Thus, all the isolates from patients with the fatal disease had the
X1 and A1 patterns, whereas the majority of the isolates from patients with nonfatal typhoid fever possessed
the X2 and A2 patterns. The data suggest that there is an association among strains of S. typhi between
genotype, as assessed by PFGE patterns, and the capability to cause fatal illness. Analysis of blood and fecal
isolates of S. typhi from the same patient also indicated that some genetic changes occur in vivo during the
course of infection. |
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