PCR-enzyme-linked immunosorbent assay and sequencing as an alternative to serology for M-antigen typing of Streptococcus pyogenes

Saunders, Nicholas A.; Hallas, Gillian; Gaworzewska, Eva; Metherell, Louise; Efstratiou, Androulla; Hookey, J.V.; George, Robert C.

doi:10.1128/jcm.35.10.2689-2691.1997

Cited by 20 publications

(9 citation statements)

References 12 publications

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“…Concordance between VT and emm ST is a significant observation because it gives insight into the overall diversity of the virulence locus and allows discrimination of different emm STs. Vir typing has clear-cut advantages over randomly amplified polymorphic DNA analysis (9,12) and M typing with oligonucleotide probes (20,21,26,32). It has recently been proposed that routine emm sequencing may be used to designate the M type (1,2).…”

Section: Discussionmentioning

confidence: 99%

Group A Streptococcal Vir Types Are M-Protein Gene (emm) Sequence Type Specific

et al. 1998

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The M-protein genes (emm genes) of 103 separate impetiginous Streptococcus pyogenes isolates were sequenced and the sequence types were compared to the types obtained by Vir typing. Vir typing is based on restriction fragment length polymorphism (RFLP) analysis of a 4- to 7-kb pathogenicity island encodingemm and other virulence genes. By using bothHaeIII and HinfI to generate RFLP profiles, complete concordance between Vir type and emm sequence type was found. Comparison of the emm sequences with those in GenBank revealed new sequence types sharing less than 90% identity with known types. Diversity in the emm sequence was generated by corrected frameshift mutations, point mutations, and small in-frame mutations.

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Section: Discussionmentioning

confidence: 99%

Group A Streptococcal Vir Types Are M-Protein Gene (emm) Sequence Type Specific

et al. 1998

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“…Sequencing of the 59 end of the emm gene is recommended as the molecular 'gold standard' for GAS typing, and has a 100 % typability rate. In order to achieve similar results with other molecular typing methods, such as capture enzyme immunoassay (EIA) (Saunders et al, 1997), in which specific probes are used, the isolates would have to be tested against a very large range of probes, including those for the subtypes. Although EIA is a very useful technique for screening isolates against the common types, it would not recognize any new emm types that may emerge.…”

Section: Emm Sequence Typingmentioning

confidence: 99%

Molecular characterization of clinical isolates of M non-typable group A streptococci from invasive disease cases

Tanna¹,

Emery²,

Dhami³

et al. 2006

Journal of Medical Microbiology

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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 2000-2002. 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 nontypable (MNT) isolates, were isolated from the London region.

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“…The serological antigen typing introduced by Rebecca Lancefield provided the basis of GAS M typing, and has been further enhanced by the implementation of molecular approaches directed towards Abbreviations: CDC, Centers for Disease Control and Prevention; GAS, group A streptococcus; iGAS, invasive GAS; KTL, National Public Health Institute of Finland; MLST, multilocus sequence typing; NIDR, National Infectious Disease Register; NT, non-typable; SOF, serum opacity factor. the M protein emm gene (Lancefield, 1962;Podbielski et al, 1991;Beall et al, 1996;Saunders et al, 1997;Facklam et al, 1999). emm typing is based on the determination of differences in the 59 end of the emm gene encoding the hypervariable and outward-projecting amino-terminal portion of the M protein (Fischetti, 1989;Beall et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

emm typing of invasive T28 group A streptococci, 1995–2004, Finland

Siljander¹,

Toropainen²,

Muotiala³

et al. 2006

Journal of Medical Microbiology

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A total of 985 group A streptococcus (GAS) bacteraemia isolates collected in Finland during 1995Finland during -2004 were T-serotyped, and of these, 336 isolates of serotype T28 were subjected to further emm typing. The total number of isolates referred per year showed an increase within the study period, from 43 in 1995 to 130 in 2004. The annual incidence of invasive GAS (iGAS) bacteraemia showed a general increase during the study period, from 1?1 to 2?5 per 100 000 population. Serotype T28 remained among the most common serotypes, in addition to serotypes TB3264 and T1. The serotype T28 isolates were found to be distributed across six distinct emm types: emm28, emm77, emm53 (including subtypes 53.2 and 53.4), emm87, emm2 and emm4. The serotype distribution and the emm type distribution of serotype T28 fluctuated over time. Within the study period, the proportion of T28/emm28 isolates became the most prominent. During periods of low emm28 incidence, emm types 77 and 53 seemed to show a resurgence. emm typing revealed T28 isolates to be a genetically heterogeneous group harbouring a variety of distinct M proteins. This study confirms that T serotyping alone is not a sufficient method for epidemiological surveillance of iGAS. INTRODUCTIONStreptococcus pyogenes (group A streptococcus, GAS) causes a variety of diseases ranging in severity from mild respiratory tract infections to invasive infections, including cellulitis, bacteraemia, necrotizing fasciitis and toxic-shock syndrome. Invasive GAS (iGAS) diseases constitute a major global burden, resulting in hundreds of thousands of cases each year, most of which occur in less-developed countries (Carapetis et al., 2005). Population-based surveillance studies, mainly from developed countries, have documented changes in the epidemiology of GAS (Lamagni et al., 2005), and have indicated the importance of type identification for epidemiological studies (Efstratiou, 2000). The availability and application of discriminatory typing methods are essential to these studies.The classical serological typing schemes for GAS are based on the variability of surface-exposed proteins, such as the T protein, the serum opacity factor (SOF) protein and the M protein (Johnson et al., 1996). The T-agglutination test introduced in 1965 has provided a useful tool for initial screening and characterization of GAS when combined with the SOF reaction result (Moody et al., 1965; Maxted et al., 1973;Johnson & Kaplan, 1993; Johnson et al., 1996). However, the value of the serological typing methods is limited by the specificity and availability of typing sera. Conventional methods are therefore being replaced or augmented by molecular methods.The major GAS virulence factor, streptococcal M protein, has multiple functions in the pathogenicity of the bacterium, including its contribution to the antiphagocytic capacity of the bacterium, thereby promoting its invasiveness (Fischetti, 1989). M proteins or M-like proteins have been identified also in group C and G streptococci (Collins et al., 1...

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PCR-enzyme-linked immunosorbent assay and sequencing as an alternative to serology for M-antigen typing of Streptococcus pyogenes

Cited by 20 publications

References 12 publications

Group A Streptococcal Vir Types Are M-Protein Gene (emm) Sequence Type Specific

Group A Streptococcal Vir Types Are M-Protein Gene (emm) Sequence Type Specific

Molecular characterization of clinical isolates of M non-typable group A streptococci from invasive disease cases

emm typing of invasive T28 group A streptococci, 1995–2004, Finland

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