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Journal of Clinical Microbiology, 02 1995, 356-363, Vol 33, No. 2
N Schnitzler, A Podbielski, G Baumgarten, M Mignon and A Kaufhold
Many group G streptococci (GGS) isolated from infected humans (but not from
animal sources) express M or M-like proteins with biological,
immunochemical, and genetic features similar to those of group A
streptococci (GAS). To further elucidate the recently proposed M-like
protein gene (emmL gene) polymorphisms in GGS, Southern blots of genomic
DNAs from 38 epidemiologically unrelated GGS strains isolated from human
specimens and 12 GGS strains recovered from animal sources were hybridized
with oligonucleotide probes designed to specifically detect GAS M class I
and M class II M protein (emm) genes. All human- associated GGS strains
showed DNA homology to the GAS M class I emm gene probe, whereas no
hybridization was found with DNA from any of the animal-associated strains.
The emmL genes from all human isolates were amplified by PCR, and the
complete sequence of the emmL gene of the Rebecca Lancefield grouping
strain D166B was determined. Again, this gene exhibited the structural
features typical for emm genes of M class I GAS. The 5' regions of the
PCR-amplified emmL genes of the remaining 37 human GGS strains were
sequenced. This region showed a sequence diversity similar to that known
for GAS emm genes. When strains whose N- terminal emmL gene sequences
showed a homology of > 95% were defined as belonging to one genetic
type, 30 strains were segregated into six distinct genetic types, whereas
the remaining 8 strains each exhibited a unique emmL gene
sequence.(ABSTRACT TRUNCATED AT 250 WORDS)
Copyright © 1995 by the American Society for Microbiology. All rights reserved.
M or M-like protein gene polymorphisms in human group G streptococci
Institute of Medical Microbiology, Technical University RWTH Aachen, Germany.
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