The discrimination of d-tartrate positive and d-tartrate negative S. enterica subsp. enterica serovar Paratyphi B isolated in Malaysia by phenotypic and genotypic methods
- Author:
Norazah Ahmad
;
Shirley Tang Gee Hoon
;
Mohamed Kamel Abd Ghani
;
Koh Yin Tee
- Publication Type:Journal Article
- Keywords:
S. Paratyphi B, d-tartrate, lead acetate test, multiplex PCR
- From:The Malaysian Journal of Pathology
2012;34(1):35-39
- CountryMalaysia
- Language:English
-
Abstract:
Serotyping is not suffi cient to differentiate between Salmonella species that cause paratyphoid
fever from the strains that cause milder gastroenteritis as these organisms share the same serotype
Salmonella Paratyphi B (S. Paratyphi B). Strains causing paratyphoid fever do not ferment d-tartrate
and this key feature was used in this study to determine the prevalence of these strains among the
collection of S. Paratyphi B strains isolated from patients in Malaysia. A total of 105 isolates of S.
Paratyphi B were discriminated into d-tartrate positive (dT+) and d-tartrate negative (dT-) variants
by two lead acetate test protocols and multiplex PCR. The lead acetate test protocol 1 differed
from protocol 2 by a lower inoculum size and different incubation conditions while the multiplex
PCR utilized 2 sets of primers targeting the ATG start codon of the gene STM3356. Lead acetate
protocol 1 discriminated 97.1% of the isolates as S. Paratyphi B dT+ and 2.9% as dT- while test
protocol 2 discriminated all the isolates as S. Paratyphi B dT+. The multiplex PCR test identifi ed all
105 isolates as S. Paratyphi B dT+ strains. The concordance of the lead acetate test relative to that
of multiplex PCR was 97.7% and 100% for protocol 1 and 2 respectively. This study showed that
S. Paratyphi B dT+ is a common causative agent of gastroenteritis in Malaysia while paratyphoid
fever appears to be relatively uncommon. Multiplex PCR was shown to be a simpler, more rapid
and reliable method to discriminate S. Paratyphi B than the phenotypic lead acetate test.
- Full text:W020151218424753729125.pdf
