Relationships between emm and multilocus sequence types within a global collection of Streptococcus pyogenes

Bessen, Debra E.; McGregor, Karen F.; Whatmore, Adrian M.

doi:10.1186/1471-2180-8-59

Cited by 40 publications

(53 citation statements)

References 51 publications

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“…Similar to observations made with S. pyogenes (1,5), in at least some cases the S. dysgalactiae subsp. equisimilis emm type is not predictive of genetic relatedness.…”

Section: Discussionsupporting

confidence: 70%

“…equisimilis isolates, our study included multiple members of 25 different emm types. It has been known for at least the past decade that certain S. pyogenes emm types are associated with multiple clonal types that can easily be resolved by phenotypic or genotypic testing (1,4,5,34). For example, based upon a combination of phenotypic and genotypic data (T typing, antiopacity factor testing, macrorestriction profile analysis, sof gene sequence typing), classic M44-M61 and M27-M77 S. pyogenes reference strain pairs are obviously divergent clones that share the same emm sequence types (1, 2, 4).…”

Section: Discussionmentioning

confidence: 99%

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Genetic Relationships Deduced from emm and Multilocus Sequence Typing of Invasive Streptococcus dysgalactiae subsp. equisimilis and S. canis Recovered from Isolates Collected in the United States

Ahmad

Gertz

et al. 2009

J Clin Microbiol

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Beta-hemolytic group C and G streptococci cause a considerable invasive disease burden and sometimes cause disease outbreaks. Little is known about the critical epidemiologic parameter of genetic relatedness between isolates. We determined the emm types of 334 Streptococcus dysgalactiae subsp. equisimilis isolates, and attempted emm typing of 5 Streptococcus canis isolates from a recent population-based surveillance for invasive isolates. Thirty-four emm types were observed, including one from S. canis. We formulated multilocus sequence typing (MLST) primers with six of the seven loci corresponding to the Streptococcus pyogenes MLST scheme. We performed MLST with 65 of the 334 surveillance isolates (61 S. dysgalactiae subsp. equisimilis isolates, 4 S. canis isolates) to represent each emm type identified, including 2 to 3 isolates for each of the 25 redundantly represented emm types. Forty-one MLST sequence types (STs) were observed. Isolates within 16 redundantly represented S. dysgalactiae subsp. equisimilis emm types shared identical or nearly identical STs, demonstrating concordance between the emm type and genetic relatedness. However, seven STs were each represented by two to four different emm types, and 7 of the 10 S. dysgalactiae subsp. equisimilis eBURST groups represented up to six different emm types. Thus, S. dysgalactiae subsp. equisimilis isolates were similar to S. pyogenes isolates, in that strains of the same emm type were often highly related, but they differed from S. pyogenes, in that S. dysgalactiae subsp. equisimilis strains with identical or closely similar STs often exhibited multiple unrelated emm types. The phylogenetic relationships between S. dysgalactiae subsp. equisimilis and S. pyogenes alleles revealed a history of interspecies recombination, with either species often serving as genetic donors. The four S. canis isolates shared highly homologous alleles but were unrelated clones without evidence of past recombination with S. dysgalactiae subsp. equisimilis or S. pyogenes.

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“…Similar to observations made with S. pyogenes (1,5), in at least some cases the S. dysgalactiae subsp. equisimilis emm type is not predictive of genetic relatedness.…”

Section: Discussionsupporting

confidence: 70%

Section: Discussionmentioning

confidence: 99%

Genetic Relationships Deduced from emm and Multilocus Sequence Typing of Invasive Streptococcus dysgalactiae subsp. equisimilis and S. canis Recovered from Isolates Collected in the United States

Ahmad

Gertz

et al. 2009

J Clin Microbiol

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“…The emm-typing method has become the gold-standard of GAS molecular typing for surveillance and epidemiological purposes, and more than 200 emm types have been described so far. Nevertheless, in order to fully discriminate GAS clones, emm-typing should be complemented with other typing methods, like PFGE or MLST [40,41].…”

Section: Single Locus Sequence Typingmentioning

confidence: 99%

Overview of molecular typing methods for outbreak detection and epidemiological surveillance

et al. 2013

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Typing methods for discriminating different bacterial isolates of the same species are essential epidemiological tools in infection prevention and control. Traditional typing systems based on phenotypes, such as serotype, biotype, phage-type, or antibiogram, have been used for many years. However, more recent methods that examine the relatedness of isolates at a molecular level have revolutionised our ability to differentiate among bacterial types and subtypes. Importantly, the development of molecular methods has provided new tools for enhanced surveillance and outbreak detection. This has resulted in better implementation of rational infection control programmes and efficient allocation of resources across Europe. The emergence of benchtop sequencers using next generation sequencing technology makes bacterial whole genome sequencing (WGS) feasible even in small research and clinical laboratories. WGS has already been used for the characterisation of bacterial isolates in several large outbreaks in Europe and, in the near future, is likely to replace currently used typing methodologies due to its ultimate resolution. However, WGS is still too laborious and time-consuming to obtain useful data in routine surveillance. Also, a largely unresolved question is how genome sequences must be examined for epidemiological characterisation. In the coming years, the lessons learnt from currently used molecular methods will allow us to condense the WGS data into epidemiologically useful information. On this basis, we have reviewed current and new molecular typing methods for outbreak detection and epidemiological surveillance of bacterial pathogens in clinical practice, aiming to give an overview of their specific advantages and disadvantages.

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“…The N terminus consists of a highly variable amino acid sequence, resulting in antigenic diversity, and is the basis for a nucleotide-based emm-typing scheme (9). There are at least 220 different emm types and subtypes of GAS, and new types are still being identified (8,10,11). Temporal, geographic, and seasonal variations in the dominant strains are well described and can result in variable epidemiological characteristics of disease (12).…”

mentioning

confidence: 99%

Streptococcus pyogenes emm Types and Clusters during a 7-Year Period (2007 to 2013) in Pharyngeal and Nonpharyngeal Pediatric Isolates

et al. 2015

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Group A streptococcus (GAS) is an important cause of morbidity and mortality worldwide. Surveillance of emm types has important implications, as it can provide baseline information for possible implementation of vaccination. A total of 1,349 GAS pediatric isolates were collected during a 7-year period (2007 to 2013); emm typing was completed for 1,282 pharyngeal (84%) or nonpharyngeal (16%) isolates, and emm clusters and temporal changes were analyzed. Thirty-five different emm types, including 14 subtypes, were identified. The most prevalent emm types identified were 1 (16.7%), 12 (13.6%), 77 (10.9%), 4 (10.8%), 28 (10.4%), 6 (6.8%), 3 (6.6%), and 89 (6.6%), accounting for 82.3% of total isolates. Rheumatogenic emm types comprised 16.3% of total isolates. The emm types 12, 4, and 77 were more prevalent among pharyngeal isolates, and the emm types 1, 89, 6, 75, and 11 were more prevalent among nonpharyngeal isolates. The emm types identified belonged to 13 emm clusters, and the 8 most prevalent clusters comprised 97% of all isolates. There were statistically significant decreases in the prevalence of emm types 12, 4, 5, and 61 and increases in the prevalence of emm types 89, 75, and 11, compared with the period 2001 to 2006. The proposed 30-valent GAS vaccine, which is currently in preclinical studies, encompasses 97.2% of the emm types detected in our study and 97.4% of the erythromycin-resistant strains. In addition, it includes 93.3% of the emm types involved in bacteremia. A much greater diversity of GAS emm types was identified in our area than described previously. Seasonal fluctuations and the introduction of new emm types were observed. Continuous surveillance of emm types is needed in order to evaluate the possible benefits of an M protein-based GAS vaccine. Streptococcus pyogenes (group A streptococcus [GAS]) is an important cause of morbidity and mortality worldwide (1). GAS causes a broad spectrum of diseases, ranging from mild to lifethreatening invasive infections. GAS infections can also lead to immune-mediated sequelae such as rheumatic fever and glomerulonephritis, with long-term complications (2, 3).In order to yield such a diversity of clinical manifestations, GAS possesses a large number of virulence mechanisms, with a high degree of variability in virulence determinants among different GAS serotypes (4, 5). The cell wall-associated M protein, encoded by the emm gene, is a major antigenic epitope and virulence factor of GAS and forms the basis for the serotyping of GAS isolates (6). The M protein acts as an epithelial adhesion factor, inhibits phagocytosis, and allows the organism to overcome innate immune responses (7,8). The N terminus consists of a highly variable amino acid sequence, resulting in antigenic diversity, and is the basis for a nucleotide-based emm-typing scheme (9). There are at least 220 different emm types and subtypes of GAS, and new types are still being identified (8,10,11). Temporal, geographic, and seasonal variations in the dominant strains are well described and can ...

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Relationships between emm and multilocus sequence types within a global collection of Streptococcus pyogenes

Cited by 40 publications

References 51 publications

Genetic Relationships Deduced from emm and Multilocus Sequence Typing of Invasive Streptococcus dysgalactiae subsp. equisimilis and S. canis Recovered from Isolates Collected in the United States

Genetic Relationships Deduced from emm and Multilocus Sequence Typing of Invasive Streptococcus dysgalactiae subsp. equisimilis and S. canis Recovered from Isolates Collected in the United States

Overview of molecular typing methods for outbreak detection and epidemiological surveillance

Streptococcus pyogenes emm Types and Clusters during a 7-Year Period (2007 to 2013) in Pharyngeal and Nonpharyngeal Pediatric Isolates

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