Application of PCR-based serogrouping of selected Salmonella serotypes in Malaysia.
BACKGROUND
Differentiation of Salmonella enterica into its serogroups is important for epidemiological study. The objective of the study was to apply a multiplex PCR targeting serogroups A, B, C1, D, E and Vi-positive strains of Salmonella enterica commonly found in Malaysia. A separate H-typing multiplex PCR which identified flagellar antigen "a", "b" or "d" was also optimized to confirm clinical serotypes, S. Paratyphi A and S. Typhi.


METHODS
Sixty-seven laboratory Salmonella enterica strains were tested. Six sets of primers targeting defined regions of the O antigen synthesis genes (rfb gene cluster) and Vi antigen gene (viaB) were selected and combined into a multiplex PCR for O-grouping. Four primers (H-for, Ha-rev, Hb-rev and Hd-rev) were used in the second step multiplex PCR for H-typing. The optimized mPCR assays were further evaluated with 58 blind-coded Salmonella strains.


RESULTS
The multiplex PCR results obtained showed 100% concordance to the conventionally typed serogroups. Validation with 58 blind coded Salmonella strains yield 100% accuracy and specificity.


CONCLUSIONS
Based on this study, PCR serogrouping proved to be a rapid, alternative method for further differentiation of Salmonella enterica.
Lim
Bee Kim
BK
Biomedical Science and Molecular Typing Laboratory, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
Thong
Kwai Lin
KL
D015373:Bacterial Typing Techniques / Q000379:methods*; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D005407:Flagella / Q000235:genetics; D006801:Humans; D008296:Malaysia; D019081:O Antigens / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods*; D011135:Polysaccharides, Bacterial / Q000235:genetics; D019779:Salmonella enterica / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D012703:Serotyping
D017931:DNA Primers; D004269:DNA, Bacterial; D019081:O Antigens; D011135:Polysaccharides, Bacterial