J Med Microbiol 55 (2006), 1419-1423; DOI: 10.1099/jmm.0.46465-0
© 2006 Society for General Microbiology
ISSN 1473-5644
Molecular characterization of clinical isolates of M non-typable group A streptococci from invasive disease cases
Asha Tanna1,
Michaela Emery1,
Chenchal Dhami1,
Eve Arnold2 and
Androulla Efstratiou1
Respiratory and Systemic Infection Laboratory1 , and Statistics, Modelling and Bioinformatics Department2 , Health Protection Agency Centre for Infections, 61 Colindale Avenue, London NW9 5HT, UK
Correspondence
Asha Tanna
asha.tanna{at}hpa.org.uk
Received 12 December 2005
Accepted 4 July 2006
Currently there are 93 validated M serotypes of Streptococcus pyogenes, Lancefield group A streptococcus (GAS), and >130 emm genotypes. A marked increase in the number of non-typable GAS isolates (2 % in 2000, 4 % in 2001 and 9 % in 2002) from invasive disease cases referred to the authors' reference laboratory was noted during 20002002. A total of 217 (92 %) were from blood cultures, 14 (6 %) from deep abscesses and five (2 %) from aspirates. The clinical manifestations included bacteraemia, septicaemia, cellulitis, meningitis, necrotizing fasciitis and toxic-shock syndrome. In order to establish whether this increase was due to the emergence of novel types or the unavailability of M-typing sera, these isolates were subjected to emm sequencing. A total of 144 isolates (61 %) belonged to M types for which sera were no longer available; 112 (48 %) belonged to higher M types, including emm83.1 (9 %), emm94 (8 %) emm87 (6 %) and emm89 (6 %); and 32 (13 %) belonged to lower M types that were not commonly isolated in the UK, and included M25, M43, M49, M64, M73 and M74. Sixty-six (28 %) of the isolates belonged to newly designated emm types. Other isolates belonged to the novel emm types st2147, STNS1033 and st854, recently registered in the Centers for Disease Control (CDC) database by other laboratories. One novel emm type, st2161, was isolated from an injecting drug user. There were differences in the type distribution of these isolates according to geographic location. However, 90 % of emm93, one of seven predominant emm types identified amongst the collection of M non-typable (MNT) isolates, were isolated from the London region.
Abbreviations: GAS, group A streptococcus; HPA, UK Health Protection Agency; IDU, intravenous drug user; MNT, M non-typable.
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2249 - 2256.
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Copyright © 2006 Society for General Microbiology.