Rapid screening of Salmonella enterica serovars Enteritidis, Hadar, Heidelberg and Typhimurium using a serologically-correlative allelotyping PCR targeting the O and H antigen alleles.
BACKGROUND
Classical Salmonella serotyping is an expensive and time consuming process that requires implementing a battery of O and H antisera to detect 2,541 different Salmonella enterica serovars. For these reasons, we developed a rapid multiplex polymerase chain reaction (PCR)-based typing scheme to screen for the prevalent S. enterica serovars Enteritidis, Hadar, Heidelberg, and Typhimurium.


RESULTS
By analyzing the nucleotide sequences of the genes for O-antigen biosynthesis including wba operon and the central variable regions of the H1 and H2 flagellin genes in Salmonella, designated PCR primers for four multiplex PCR reactions were used to detect and differentiate Salmonella serogroups A/D1, B, C1, C2, or E1; H1 antigen types i, g, m, r or z10; and H2 antigen complexes, I: 1,2; 1,5; 1,6; 1,7 or II: e,n,x; e,n,z15. Through the detection of these antigen gene allele combinations, we were able to distinguish among S. enterica serovars Enteritidis, Hadar, Heidelberg, and Typhimurium. The assays were useful in identifying Salmonella with O and H antigen gene alleles representing 43 distinct serovars. While the H2 multiplex could discriminate between unrelated H2 antigens, the PCR could not discern differences within the antigen complexes, 1,2; 1,5; 1,6; 1,7 or e,n,x; e,n,z15, requiring a final confirmatory PCR test in the final serovar reporting of S. enterica.


CONCLUSIONS
Multiplex PCR assays for detecting specific O and H antigen gene alleles can be a rapid and cost-effective alternative approach to classical serotyping for presumptive identification of S. enterica serovars Enteritidis, Hadar, Heidelberg, and Typhimurium.
Hong
Yang
Y
Department of Population Health, The University of Georgia, Athens, GA 30602, USA. yang.hong@primuslabs.com
Liu
Tongrui
T
Lee
Margie D
MD
Hofacre
Charles L
CL
Maier
Marie
M
White
David G
DG
Ayers
Sherry
S
Wang
Lihua
L
Berghaus
Roy
R
Maurer
John J
JJ
D000483:Alleles; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics*; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D002645:Chickens / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics; D005408:Flagellin / Q000235:genetics; D006801:Humans; D019081:O Antigens / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D019779:Salmonella enterica / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D012703:Serotyping
D000942:Antigens, Bacterial; D004269:DNA, Bacterial; C022863:H antigen; D019081:O Antigens; D005408:Flagellin