TY - JOUR
T1 - Combined sigB allelic typing and multiplex PCR provide improved discriminatory power and reliability for Listeria monocytogenes molecular serotyping
AU - Nightingale, Kendra
AU - Bovell, Liselle
AU - Grajczyk, Ashley
AU - Wiedmann, Martin
N1 - Funding Information:
This work was supported by USDA Special Research Grants 2001-34459-10296 and 2002-34459-11758 (to M.W.). We thank Q. Sun (Computational Biology Service Unit, Cornell University) for his expertise in setting up the computing system to perform evolutionary analyses. We are also indebted to K. Lyles and A. Ho for their expert technical assistance with DNA sequencing as well as L. Graves and M. Samadpour for serotyping.
PY - 2007/1
Y1 - 2007/1
N2 - Conventional serotyping has traditionally been used to subtype Listeria monocytogenes, but has several limitations, including low discriminatory power and poor reproducibility. Molecular serotyping methods have been developed for L. monocytogenes, but generally show limited discriminatory power and high misclassification rates. We selected 157 Listeria isolates to evaluate a combination of a previously described multiplex PCR assay and sigB allelic typing as an alternative molecular serotyping and subtyping strategy for L. monocytogenes. While the multiplex PCR assay differentiated five L. monocytogenes subtypes (Simpson's Index of Discrimination [SID] = 0.78), including classification of the most common disease-associated serotypes (1/2a, 1/2b, 1/2c, and lineage I 4b) into four distinct groups, it misclassified 3.8% of the isolates studied here. sigB allelic typing differentiated 29 subtypes (SID = 0.87) and also allowed identification of lineage III L. monocytogenes, which could not be differentiated from the other Listeria spp. by the multiplex PCR assay. sigB allelic typing failed to differentiate serotype 1/2c and 1/2a isolates and one sigB allelic type included serotype 4b and 1/2b isolates. A molecular serotyping approach that combines multiplex PCR and sigB sequence data showed increased discriminatory power (SID = 0.91) over either method alone as well as conventional serotyping (SID = 0.87) and classifies the four major serotypes (i.e., 1/2a, 1/2b, 1/2c, and 4b) into unique subgroups with a lower misclassification rate as compared to the multiplex PCR assay. This combined approach also differentiates lineage I serotype 4b isolates from the genetically distinct serotype 4b isolates classified into lineage III.
AB - Conventional serotyping has traditionally been used to subtype Listeria monocytogenes, but has several limitations, including low discriminatory power and poor reproducibility. Molecular serotyping methods have been developed for L. monocytogenes, but generally show limited discriminatory power and high misclassification rates. We selected 157 Listeria isolates to evaluate a combination of a previously described multiplex PCR assay and sigB allelic typing as an alternative molecular serotyping and subtyping strategy for L. monocytogenes. While the multiplex PCR assay differentiated five L. monocytogenes subtypes (Simpson's Index of Discrimination [SID] = 0.78), including classification of the most common disease-associated serotypes (1/2a, 1/2b, 1/2c, and lineage I 4b) into four distinct groups, it misclassified 3.8% of the isolates studied here. sigB allelic typing differentiated 29 subtypes (SID = 0.87) and also allowed identification of lineage III L. monocytogenes, which could not be differentiated from the other Listeria spp. by the multiplex PCR assay. sigB allelic typing failed to differentiate serotype 1/2c and 1/2a isolates and one sigB allelic type included serotype 4b and 1/2b isolates. A molecular serotyping approach that combines multiplex PCR and sigB sequence data showed increased discriminatory power (SID = 0.91) over either method alone as well as conventional serotyping (SID = 0.87) and classifies the four major serotypes (i.e., 1/2a, 1/2b, 1/2c, and 4b) into unique subgroups with a lower misclassification rate as compared to the multiplex PCR assay. This combined approach also differentiates lineage I serotype 4b isolates from the genetically distinct serotype 4b isolates classified into lineage III.
KW - Listeria monocytogenes
KW - Molecular subtyping
KW - Serotyping
UR - http://www.scopus.com/inward/record.url?scp=33846011872&partnerID=8YFLogxK
U2 - 10.1016/j.mimet.2006.06.005
DO - 10.1016/j.mimet.2006.06.005
M3 - Article
C2 - 16887224
AN - SCOPUS:33846011872
SN - 0167-7012
VL - 68
SP - 52
EP - 59
JO - Journal of Microbiological Methods
JF - Journal of Microbiological Methods
IS - 1
ER -