Distribution Of Emm Types Research Articles

Epidemiological shifts in and impact of COVID-19 on streptococcal toxic shock syndrome in Japan: A genotypic analysis of group A Streptococcus isolates

ObjectivesStreptococcal toxic shock syndrome (STSS) is caused by group A Streptococcus (GAS; Streptococcus pyogenes) strains. In Japan, the number of STSS cases has decreased; however, the underlying reason remains unclear. Moreover, information on distribution and prevalence of specific emm types in STSS cases is scarce. Hence, we investigated the reason for the decreased number of STSS cases in Japan. MethodsWe genotyped emm of 526 GAS isolates obtained from 526 patients with STSS between 2019 and 2022. The distributions of emm types in each year were compared. ResultsThe emm1 type was predominant, with the highest proportion in 2019, which decreased after 2020 following the onset of the coronavirus disease 2019 (COVID-19) pandemic. Strains isolated during the pandemic correlated with strains associated with skin infection, whereas those isolated during the prepandemic period correlated with strains associated with both throat and skin infections. The decrease in the annual number of STSS cases during the COVID-19 pandemic could be due to a decreased proportion of strains associated with pharyngeal infections. ConclusionsPotential associations between pandemic and STSS numbers with respect to public health measures, such as wearing masks and changes in healthcare-seeking behavior, may have affected the number of GAS-induced infections.

Epidemiological analysis of Group A streptococcus infection diseases among children in Beijing, China under COVID-19 pandemic

BackgroundGroup A streptococcus is human-restricted gram-positive pathogen, responsible for various clinical presentations from mild epidermis infections to life threatened invasive diseases. Under COVID-19 pandemic,. the characteristics of the epidemic strains of GAS could be different.PurposeTo investigate epidemiological and molecular features of isolates from GAS infections among children in Beijing, China between January 2020 and December 2021. Antimicrobial susceptibility profiling was performed based on Cinical Laboratory Sandards Institute. Distribution of macrolide-resistance genes, emm types, and superantigens was examined by polymerase chain reaction.Results114 GAS isolates were collected which were frequent resistance against erythromycin (94.74%), followed by clindamycin (92.98%), tetracycline (87.72%). Emm12 (46.49%), emm1 (25.44%) were dominant emm types. Distribution of ermB, ermA, and mefA gene was 93.85%, 2.63%, and 14.04%, respectively. Frequent superantigenes identified were smeZ (97.39%), speG (95.65%), and speC (92.17%). Emm1 strains possessed smeZ, ssa, and speC, while emm12 possessed smeZ, ssa, speG, and speC. Erythromycin resistance was predominantly mediated by ermB. Scarlet fever strains harbored smeZ (98.81%), speC (94.05%). Impetigo strains harbored smeZ (88.98%), ssa (88.89%), and speC (88.89%). Psoriasis strains harbored smeZ (100%).ConclusionsUnder COVID-19 pandemic, our collections of GAS infection cutaneous diseases decreased dramatically. Epidemiological analysis of GAS infections among children during COVID-19 pandemic was not significantly different from our previous study. There was a correlation among emm, superantigen gene and disease manifestations. Long-term surveillance and investigation of emm types and superantigens of GAS prevalence are imperative.

A global snapshot on the prevalent macrolide-resistant emm types of Group A Streptococcus worldwide, their phenotypes and their resistance marker genotypes during the last two decades: A systematic review.

Watchful epidemiological surveillance of macrolide-resistant Group A Streptococcus (MRGAS) clones is important owing to the evolutionary and epidemiological dynamic of GAS. Meanwhile, data on the global distribution of MRGAS emm types according to macrolide resistance phenotypes and genotypes are scant and need to be updated. For this, the present systematic review analyses a global set of extensively characterized MRGAS isolates from patients of diverse ages and clinical presentations over approximately two decades (2000 to 2020) and recaps the peculiar epidemiological features of the dominant MRGAS clones. Based on the inclusion and exclusion criteria, 53 articles (3593 macrolide-resistant and 15,951 susceptible isolates) distributed over 23 countries were dissected with a predominance of high-income countries over low-income ones. Although macrolide resistance in GAS is highly variable in different countries, its within-GAS distribution seems not to be random. emm pattern E, 13 major emm types (emm12, 4, 28, 77, 75, 11, 22, 92, 58, 60, 94, 63, 114) and 4 emm clusters (A-C4, E1, E6, and E2) were significantly associated with macrolide resistance. emm patterns A-C and D, 14 major emm types (emm89, 3, 6, 2, 44, 82, 87, 118, 5, 49, 81, 59, 227, 78) and 3 well-defined emm clusters (A-C5, E3, and D4) were significantly associated with macrolide susceptibility. Scrutinizing the tendency of each MRGAS emm type to be significantly associated with specific macrolide resistance phenotype or genotype, interesting vignettes are also unveiled. The 30-valent vaccine covers ~95% of MRGAS isolates. The presented data urge the importance of comprehensive nationwide sustained surveillance of MRGAS circulating clones particularly in Low and Middle income countries where sampling bias is high and GAS epidemiology is obfuscated and needs to be demystified.

Systematic Review of Group A Streptococcal emm Types Associated with Acute Post-Streptococcal Glomerulonephritis.

Acute post-streptococcal glomerulonephritis (APSGN) is a postinfectious immune-mediated kidney disease associated with group A Streptococcus (GAS). The prevalence of APSGN varies within and between countries and is influenced by socioeconomic, host, and bacterial factors. The disease is more prevalent in developing countries and resource-poor settings of developed countries, such as the Indigenous populations residing in tropical Australia. The M-protein is a universally present GAS surface antigen that is the focus of molecular typing and vaccine research. Early reports suggested that some M-proteins (emm types) are more likely to cause APSGN than others. Here, we present the first systematic review of the global distribution of APSGN-associated GAS emm types. There were 46 emm types among the 676 cases described in 15 reviewed articles. Only 43% APSGN cases would have had theoretical coverage from the experimental M protein-based GAS vaccine. Vaccine coverage was higher in regions such as North America (97%) and the United Kingdom (98%) than Africa (67%) and Australia (38%). Variable vaccine coverage against APSGN- associated emm types highlights the need for further research into this disease, particularly in settings of poverty, where APSGN prevalence is higher. Three GAS emm types (emm49, emm60, and emm55) consistently occur in APSGN cases around the world. Future studies would therefore benefit from examining the genomic epidemiology of these emm types to unravel potential markers of APSGN.

Distribution of emm types of beta hemolytic streptococci associated with necrotizing fascitis: Clinical profile and outcome

Distribution of emm types of beta hemolytic streptococci associated with necrotizing fascitis: Clinical profile and outcome

Group A streptococcal strains isolated in Lao People's Democratic Republic from 2004 to 2013.

Epidemiological data regarding group A streptococcal (GAS) infections in South East Asia are scarce with no information from Laos. We characterized emm types, emm clusters and the antibiotic resistance profile of 124 GAS isolates recovered in Laos during 2004-2013. Most strains were recovered from skin and invasive infections (76% and 19%, respectively). Thirty-four emm types were identified as belonging to 12 emm clusters and no novel emm types were identified. No significant differences were observed in the distribution of emm types or emm clusters according to age or site of recovery (skin or invasive infections). There was moderate strain diversity in this country but considerable differences in emm-type distribution between Laos, Thailand and Cambodia. Vaccine coverage was high for the J8 vaccine candidate. The theoretical coverage for the 30-valent vaccine candidate needs further investigation. Antibiotic resistance was moderate to erythromycin and chloramphenicol (8% and 7%, respectively) and low to ofloxacin (<1%).

Emm types of mutation in scarlet-fever-related group A streptococcal, among children in Beijing, 2011-2014

To understand the distribution of emm gene types related to group A streptococcus-caused scarlet fever among children in Beijing and to analyze the relationship between the mutation of the emm types and scarlet fever. Nasopharyngeal swab samples were collected from the scarlet fever cases diagnosed in 36 hospitals in Beijing to isolate the GAS strains from May to July, betgween 2011 and 2014. Genotyping of emm gene was performed with PCR and N-terminal gene fragments of M protein were sequenced. Data of all the scarlet fever cases in Beijing that reported through the National Notifiable Infectious Disease Surveillance System (NNIDSS) , were gathered and analyzed. Among the collected 2 161 nasopharyngeal swabs, 762 GAS strains were identified (35.3%). In addition, 7 emm types were detected, in which emm12 accounted for 69.4% (529/762) , emm1 accounted for 29.8% (227/762) , and other five types (emm 11, 22, 75, 89, and 128) accounted for 0.8% (6/762) , respctively. Compared with the emm types detected between 2011 and 2014, emm12, emm1 and other types accounted for 82.2% (295/359) , 16.7% (60/359) and 1.1% (4/359, including emm11, 22 and 89) in 2011 respectively.emm12, emm1 and emm75 accounted for 77.3% (123/163) , 23.9% (39/163) and 0.6% (1/163) respectively in 2012. emm12 and emm1 accounted for 50.7% (38/75) and 49.3% (37/75) in 2013 while emm12, emm1 and emm128 accounted for 44.2% (73/165) , 55.2% (91/165) and 0.6% (1/165) respectively in 2014. The differences of the constitution of emm types from 2011 to 2014 appeared statistically significant (P<0.001). In 2011 and 2012, major type appeared as emm12, but in 2014, emm1 became predominant. A total of 6 152 cases were reported in 2011, while 2 908, 2 048 and 3 918 cases were reported in 2012, 2013 and 2014 respectively. Age specific differences were noticed in the distribution of emm types GAS strains in 2011, with the number of emm12 strains detected higher in 1-5 year olds than in age group > 5 years (P<0.05). There were area specific differences in distribution of emm types of GAS strains seen in 2011 and 2013. In 2011, the number of emm1 strains detected in urban area was higher than in suburb area (P<0.05). However, in 2013, the number of emm1 strains detected in suburb area was seen higher than in urban area (P< 0.05). GAS with emm12 and GAS emm1 appeared interchangeably predominant in Beijing from 2011 to 2014. Changes in predominant emm types seemed also related to the trends of incidence rates on scarlet fever.

Epidemiology of invasive group A Streptococcus infections in Sydney, Australia

There is concern of global resurgence of invasive group A Streptococcus (iGAS) infections. We compared the clinical and molecular epidemiology of patients admitted with iGAS over two time periods, 2008 and 2010, in Western Sydney, Australia. The annual incidence was 19 cases per 100,000 admissions in 2008, compared to 33 per 100,000 in 2010. An increasing proportion of patients died (0% versus 13%), had an APACHE II score ≥30 (0% versus 19%), and had no known risk-factors (12% versus 25%). A potential skin source was identified as a trigger in fewer cases in 2010 (36% versus 11%). In total, there were 27 different emm types and 11 different emm clusters. There were some new emm types/clusters in 2010 that were not present in 2008. However, the study was not adequately powered to detect statistically significant differences in the distribution of emm types (p = 0.06) and emm clusters (p = 0.16) between the two years. There were also no clear associations between emm types/clusters and severity and clinical manifestations of iGAS infections. Although the proposed 30-valent M protein vaccine encompasses only 47% of our isolates, it will likely provide coverage for at least 71% of iGAS infections due to cross-opsonisation.

Distribution of emm types among group A Streptococcus isolates from children in Korea

We analyzed 155 clinical group A Streptococcus (GAS) isolates from children at the Seoul National University Children's Hospital between 1991 and 2012 and the Seoul National University Bundang Hospital between 2006 and 2012. The erythromycin resistance rate was 10.3% (16/155), and all isolates during the recent 3years were susceptible to erythromycin. Among isolates, emm1 (19.4%), emm12 (18.7%), and emm4 (18.1%) were the most prevalent emm types. According to clinical disease, emm1 was most common in invasive GAS infections (47.4%), and emm4, in scarlet fever (48.8%). From 2010 to 2012, an increase in invasive GAS infections and scarlet fever that correlated with an increase in emm1 and emm4 types was observed. The speC detection rate was higher in patients with scarlet fever than in those with other GAS infections (P=0.017). Recently, invasive GAS infections and scarlet fever were associated with an increase in emm1 and emm4, respectively.

Changes in Streptococcus pyogenes causing invasive disease in Portugal: Evidence for superantigen gene loss and acquisition

The emergence of highly virulent and successful Streptococcus pyogenes (group A streptococci – GAS) clones has been attributed to the exchange of virulence factors by lateral gene transfer mechanisms, which strongly contribute to genomic diversity. We characterized a collection of 191 GAS isolates recovered from normally sterile sites in Portugal during 2006–2009 and compared them to invasive isolates obtained during 2000–2005. Antimicrobial resistance rates did not change significantly between the two periods and were generally low. In 2006–2009, emm1, emm89, emm3, and emm6 represented 60% of the isolates. The chromosomally encoded superantigen (SAg) genes speG and smeZ were present in the majority (>90%) of the isolates, while speJ was found in only 45%. The phage encoded SAgs varied greatly in prevalence (2–53%). The distribution of emm types, pulsed-field gel electrophoresis profiling (PFGE) clusters, and SAg profiles changed significantly between the periods, although there were no statistically supported changes in the prevalence of individual types. While the macrolide susceptible clone emm1-T1-ST28 remained dominant (28%), there was a significant decrease in clonal diversity as indicated by both PFGE profiling and emm typing. This was accompanied by intra-clonal divergence of SAg profiles, which was statistically confirmed for isolates representing emm1, emm28, and emm44. This diversification was associated with the loss and acquisition of SAg genes, carried by phages and of chromosomal origin. These data suggest an ongoing genomic diversification of GAS invasive isolates in Portugal that may contribute to the persistence of clones with improved fitness or virulence.

Comparative analysis of emm types, superantigen gene profiles and antibiotic resistance genes among Streptococcus pyogenes isolates from ocular infections, pharyngitis and asymptomatic children in south India

Group A Streptococcus (Streptococcus pyogenes) is responsible for a wide array of infections and incidence is high in developing countries like India. Although distribution of emm types of S. pyogenes in India has been described, its association with the virulence genes and ocular isolates is less concentrated. In the present study emm type surveillance as well as its association with toxin gene profile was analyzed. Ocular infected cases such as lacrimal abscess, corneal ulcers, mucocoele showed the presence of 20 S. pyogenes isolates. For noninvasive isolates, we screened 370 pharyngitis cases and 400 asymptomatic school children and recovered 33 pharyngitis and 14 carrier isolates respectively. 14 Emm type distributions were observed in ocular isolates, 11 emm types each in pharyngitis and asymptomatic carrier isolates. The two dominant emm types, emm49 and emm63 were accounted for 33% of the total S. pyogenes isolates. Among ocular isolates, slo, smeZ, speB and speG were found in >50% of isolates, in pharyngitis smeZ (48%), speB (45%) and speG (42%) genes were found to be prevalent. Alarmingly, carrier isolates showed more prevalence to virulence genes than the ocular and pharyngitis isolates with speF (79%), speB, speG (64%), slo and sil (64%). Among the three groups, pharyngitis isolates harbored more prtF1 (33%) and prtF2 (94%) than the asymptomatic carriers (28% and 71%) and the ocular isolates (45% and 40%). 450bp Size band in prtF1 and 350bp size band in prtF2 showed dominance. Among the three groups tested, the distribution of ermB and mefA was high in pharyngitis isolates (30%) where 10 isolates showed the presence of both genes. None of the isolates showed the presence of ermA and tetO genes. Dendrogram generated based on the virulence and antibiotic resistance gene profiles revealed that except one cluster, all other clusters showed some correlation with ocular, pharyngitis and asymptomatic carrier isolates, irrespective of their emm types.

Unique distribution of emm types and superantigen gene profiles of group A streptococci isolated in Thailand

Unique distribution of emm types and superantigen gene profiles of group A streptococci isolated in Thailand

Distribution of emm types in invasive and non-invasive group A and G streptococci

Our study describes the emm type distributions of invasive and non-invasive group A streptococci (GAS) and group G streptococci (GGS) strains in one of the biggest Health Districts in Finland. A total of 571 GAS or GGS were recovered from patients with invasive or non-invasive infections during a 1-year period in 2008-2009 in Pirkanmaa Health District in Finland. We describe here the emm type distributions of GAS and GGS collected from throat (n = 246), pus (n = 217), deep tissue (n = 56) and blood (n = 52). The most common emm types among GAS were emm77, emm1, emm28, emm89 and emm12. Among GGS, the most common emm types were stG480, stG643, stG6, stC6979 and stG485. Some emm types were found to associate with certain infection focus. In GAS, emm77 associated with pus isolates, whereas emm1 and emm12 were more frequent among throat isolates. In GGS, stG480 was more commonly found from throat isolates.

Emergence of uncommon emm types of Streptococcus pyogenes among adult patients in southern Taiwan

Streptococcus pyogenes isolated from adult patients during a 12-year period in southern Taiwan were analyzed to estimate the distribution of emm types and their correlation with disease manifestations and patient age. Three hundred thirty-four invasive and noninvasive isolates collected from patients older than 20 years between 1997 and 2008 at National Cheng Kung University Hospital were included for emm typing. A correlation between emm type, disease manifestations, and patient ages was analyzed. The nine most prevalent types were emm11, emm12, emm4, emm1, Sp9458/VT8, emm81, emm106, emm13, and emm75. Formerly rare emm types, including emm11, emm81, and emm102, emerged dramatically after 2004 in southern Taiwan. Type emm11 was significantly associated with both superficial infections and cellulitis. In addition, types emm13, emm81, and emm106 were more prevalent in patients older than 50 years and significantly associated with specific invasive disease manifestation. These results suggest new emm types (emm11, emm81, and emm102) of Spyogenes were introduced into the adult population in southern Taiwan after 2004. The rarely reported emm types, including emm13, emm81, and emm106, caused invasive diseases more often in adult patients.

Invasive infection caused by Streptococcus dysgalactiae subsp. equisimilis: characteristics of strains and clinical features

Among clinically isolated β-hemolytic streptococci, Streptococcus pyogenes and S. agalactiae were considered the main pathogens in humans until recently. In 1996, S. dysgalactiae subsp. equisimilis (SDSE) was proposed as a novel taxon among human-derived streptococcal isolates. SDSE has Lancefield group C or G antigens, exhibits strong β-hemolysis, and exerts streptokinase activity upon human plasminogen and proteolytic activity upon human fibrin. Similarly to group A streptococci, SDSE possesses virulence factors including M protein, streptolysin O, streptolysin S, streptokinase, hyaluronidase, C5a peptidase, and others. SDSE may exist among the normal flora of the skin, oropharynx, and gastrointestinal and genitourinary tracts. In the twenty-first century, invasive SDSE infection (i.e., cellulitis, urosepsis, and pneumonia) leading to various disseminated diseases is being diagnosed increasingly in Japan, elsewhere in Asia, in Europe, and in America. Particularly, among elderly patients, these invasive diseases are encountered increasingly in Japanese hospital emergency departments. Analysis of the part of the emm gene encoding the amino acid sequence at the N-terminal end of the M protein is used to determine the molecular epidemiology of SDSE. The distribution of emm types from patients with invasive or noninvasive infections differs between surveillance results from different countries. In this review, we summarize the characteristics of phenotypes and virulence factors in SDSE strains; the review also focuses on emerging SDSE infectious disease and future vaccination research.

Prevalence of emm types of Group A streptococci recovered from school children and hospital patients in Bangalore City, India

A total of sixty non repetitive isolates of group A streptococci (GAS) recovered from throat cultures of asymptomatic school children (n = 36), school children with clinical pharyngitis (n = 9) and hospital patients with clinical pharyngitis (n = 4) as well as diverse clinical samples from invasive GAS disease (n = 11) were subjected to emm typing. A total of 35 emm types including 3 new subtypes were identified among them. Types emm 12 (16.6%) and emm 71 (6.6%) were the most prevalent. The distribution of emm types identified among school children were similar to those encountered among invasive isolates but was significantly different from those reported elsewhere in India. Our study confirms the high diversity among Indian GAS isolates as well as significant regional differences among the distribution of emm types.

Diversity of emm sequence types in group A beta-haemolytic streptococci in two remote Northern Territory Indigenous communities: Implications for vaccine development

There is a high burden of disease due to group A streptococcus (GAS) in remote Northern Territory (NT) Indigenous communities. A proposed 26-valent GAS M-type vaccine covers 80–90% of pharyngeal and invasive isolates in the US. We examined the diversity and distribution of emm types in two remote Indigenous communities in the NT Top End over a 17-year period and compared them to the proposed vaccine types. Eighty emm types were identified between 1991 and 2007. Diversity in both communities was high (overall Simpson's index 0.976), but varied between communities. Prior to 2004, 71 emm types were identified and an additional 9 emm types were identified during a period of active surveillance in 2004–2005. The proposed 26-valent vaccine would be expected to cover only 20% of emm types recovered in this study. Of the 80 emm types, 16 (20%) were new sequence types identified since the last assignment of M types in 2002. The diversity of streptococcal isolates was higher than that reported from most industrialized countries, and similar to that described in several developing countries. A vaccine based on such a variable antigen is unlikely to provide effective protection in the highest risk populations.

Distribution of emm types among group A streptococcal isolates from Serbia

This is the first study concerning the molecular epidemiology of group A streptococcus in Serbia and includes 145 isolates from patients with various infections during the period 2001–2007. The emm types, superantigen profile and susceptibility pattern were determined. Among 31 emm types identified, the most prevalent were emm6, emm12, emm1, and emm58. All isolates showed uniform antimicrobial susceptibility to all tested antibiotics, with the exception of tetracycline and erythromycin (41% and 0.7% resistant strains, respectively). Significant heterogeneity of emm types was found, with a high frequency of emm6 and emm58, as well as a considerable prevalence of tetracycline resistance, and a low level of macrolide resistance.

Epidemiological markers of Streptococcus pyogenes strains in Tunisia

To further understand the epidemiology of Streptococcus pyogenes or group A streptococcus (GAS) infections in Tunisia, phenotypic and genomic markers of GAS isolates, including antibiotic susceptibility, biotypes, T and emm types and toxin gene profiles, have been characterized. A total of 103 isolates, collected between 2000 and 2006, were investigated; 47 were recovered from invasive infections, and 56 from non-invasive infections. Rates of resistance to tetracycline, erythromycin, clindamycin and rifampin were 70.8%, 4.8%, 4.8% and 0.9%, respectively. High levels of resistance to streptomycin and kanamycin were observed in 1.9% and 4.8% of isolates, respectively. Biotype 3 was most common. Twenty different T patterns were observed, with a predominance of T3/13/B3264, and 38 different emm types. In both invasive and non-invasive isolates, emm118 (9.7%), emm42 (8.7%), emm1 (7.8%), st432 (6.8%), emm28 (5.8%) and emm76 (5.8%) were the most prevalent types; emm1, emm76 and emm18 were mainly observed among invasive infections, whereas emm118 (12.5%), emm42 (10.7%) and emm28 (8.9%) were predominant among non-invasive infections. The speB gene was detected in all isolates, but there were variable frequencies of speA, speC and ssa (20.3%, 32% and 25.2% respectively). Significant associations of emm1, emm18 and emm3 with speA and of emm4 and st432 with ssa were found. This first report from Tunisia revealed a unique emm distribution of GAS that differs from those of other regions. This information on the distribution of such emm types will be useful for the development of an appropriate vaccine in a country where the incidence of rheumatic fever remains high.

Macrolide resistance in Streptococcus pyogenes: prevalence, resistance determinants, and emm types

To investigate the antimicrobial resistance trends and the distribution of emm types of group A streptococci (GAS), we examined 1160 clinical isolates of GAS collected between 2003 and 2006. Susceptibilities to commonly used antimicrobial agents were determined by Etest, and macrolide resistance genes were detected by polymerase chain reaction (PCR). GAS isolates were typed by polymerase chain reaction PCR and sequencing of emm gene. The rates of resistance to erythromycin (ERY), clindamycin, azithromycin, tetracycline, and chloramphenicol were 14.9%, 1.4%, 14.9%, 18.9%, 0.6%, respectively. None of the isolates exhibited resistance to penicillin, ceftriaxone, linezolid, moxifloxacin, rifampicin, or vancomycin. Macrolide resistance increased from 12.1% in 2003 to 18.8% in 2006 ( P = 0.02). Of 173 ERY-resistant GAS isolates, 93 (53.7%) harbored the mefA gene, 70 (40.4%) the ermA, and 10 (5.8%) the ermB. Eighty percent of the observed emm types are covered by the proposed 26-valent GAS vaccine. Among 173 ERY-resistant isolates, the predominant emm types were 12 (19.5%), 77 (17.9%), and 4 (16.8%), and among 770 ERY-susceptible isolates, the predominant types were 1 (18.8%), 12 (17.5%), 28 (13.8%). The observed antimicrobial resistance trends and the distribution of specific emm types have implications in guiding empiric therapy and in developing vaccine strategies to prevent GAS infections.