Changes in emm types and superantigen gene content of Streptococcus pyogenes causing invasive infections in Portugal

Friães, Ana; Melo‐Cristino, José; Ramírez, Mario

doi:10.1038/s41598-019-54409-2

Cited by 22 publications

(14 citation statements)

References 40 publications

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“…Nonetheless, different patterns of toxin gene profiling within multiple emm types are usually reflected by ongoing horizontal transfer of phage-encoded superantigen genes over time [60].…”

Section: Tablementioning

confidence: 99%

Distribution of virulence genes and the molecular epidemiology of Streptococcus pyogenes clinical isolates by emm and multilocus sequence typing methods

Hamzah

Desa

Jasni

et al. 2020

Preprint

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Background: Streptococcus pyogenes has a variety of virulence factors and the predominant invasive strains differ according to specific emm types and geographical orientation. Although emm typing is commonly used as the gold standard method for the molecular characterization, multilocus sequence typing (MLST) has become an important tool for comparing the genetic profiles globally. This study aimed to screen selected virulence genes from invasive and non-invasive clinical samples and to characterize the molecular epidemiology by emm typing and MLST methods. Methods: A total of 42 S. pyogenes isolates from invasive and non-invasive samples collected from 2014 to 2015 from two different tertiary hospitals were investigated for the distribution of virulence factors and their molecular epidemiology by emm and multilocus sequence typing methods. Detection of five virulence genes (speA , speB , speJ , ssa and sdaB) was performed using multiplex polymerase chain reaction (PCR) using the standard primers and established protocol. Results: Multiplex PCR analysis revealed that sdaB/speF (78.6%) and speB (61.9%) were the predominant virulence genes. Regardless of the type of invasiveness, diverse distribution of emm types/subtypes was noted which comprised of 27 different emm types/subtypes. The predominant emm types/subtypes were emm63 and emm18 with each gene accounted for 11.8% whereas 12% for each gene was noted for emm28, emm97.4 and emm91. The MLST revealed that the main sequence type (ST) in invasive samples was ST402 (17.7%) while ST473 and ST318 (12% for each ST) were the major types in non-invasive samples. Out of 18 virulotypes, Virulotype A (five genes, 55.6%) and Virulotype B (two genes, 27.8%) were the major virulotypes found in this study. Phylogenetic analysis indicated the presence of seven different clusters of S. pyogenes. Interestingly, Cluster VI showed that selected emm/ST types such as emm71/ST318 (n=2), emm70.1/ST318 (n=1), emm44/ST31 (n=1) and emm18/ST442 (n=1) have clustered within a common group (Virulotype A) for both hospitals studied. Conclusion: The present study showed that group A streptococci (GAS) are genetically diverse and possess virulence genes regardless of their invasiveness. Majority of the GAS exhibited no restricted pattern of virulotypes except for a few distinct clusters. Therefore, it can be concluded that virulotyping is partially useful for characterizing a heterogeneous population of GAS in hospitals.

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“…Nonetheless, different patterns of toxin gene profiling within multiple emm types are usually reflected by ongoing horizontal transfer of phage-encoded superantigen genes over time [60].…”

Section: Tablementioning

confidence: 99%

Distribution of virulence genes and the molecular epidemiology of Streptococcus pyogenes clinical isolates by emm and multilocus sequence typing methods

Hamzah

Desa

Jasni

et al. 2020

Preprint

View full text Add to dashboard Cite

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“…Interestingly, the proportion of emm12 and emm1 in this study was similar to that reported previously. These results showed that the emm genotypes of GAS isolates changed significantly in recent years as compared to those identified in the (8%), and emm6 (7%) [31]. Furthermore, the isolates of emm60.1 and emm63.0 genotypes were prevalent in the children from the villages of Guizhou Province in China, which led to the outbreak of acute glomerulonephritis in 2005 [40].…”

Section: Antimicrobial Susceptibility Testing Resultsmentioning

confidence: 87%

Molecular epidemiology and antimicrobial resistance of group A streptococcus recovered from patients in Beijing, China

Zhang

Zhao

et al. 2020

Preprint

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Background: Group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern. The objective of this study was to investigate the molecular epidemiological characteristics and antimicrobial resistance of GAS isolates from patients in Children’s Hospital in Beijing. Methods: From 2016 to 2017, pharyngeal swab samples were collected from the outpatients in Children’s Hospital, Capital Institute of Pediatrics, who were diagnosed with scarlet fever. Antimicrobial susceptibility test was performed according to the distribution of conventional antibiotics and Clinical and Laboratory Standards Institute (CLSI) recommendations. The distribution of the macrolide-resistance genes (ermB, ermA, mefA), emm (M protein-coding gene) typing, and superantigens (SAg) gene profiling were examined by polymerase chain reaction (PCR). Results: A total of 297 GAS isolates were collected. The susceptibility of the isolates to penicillin, ceftriaxone, and levofloxacin was 100%. The resistance rate to erythromycin and clindamycin was 98.3% and 96.6%, respectively. The dominant emm types were emm12 (65.32%), emm1 (27.61%), emm75 (2.69%), and emm89 (1.35%). Of the 297 isolates, 290 (97.64%) carried the ermB gene, and 5 (1.68%) carried the mefA gene, while none carried the ermA gene. The most common superantigen genes identified from GAS isolates were smeZ (96.97%), speC (92.59%), speG (91.58%), ssa (85.52%), speI (54.55%), speH (52.19%), and speA (34.34%). Isolates with the genotype emm1 possessed speA, speC, speG, speJ, speM, ssa, and smeZ, while emm12 possessed speC, speG, speH, speI, speM, ssa, and smeZ superantigens. Conclusions: The prevalent strain of GAS isolates in Beijing has a high resistance rate to macrolides; however, penicillin can still be the preferred antibiotic for treatment. Erythromycin resistance was predominantly mediated by ermB. The common emm types were emm12 and emm1. There was a correlation between emm and the superantigen gene. Thus, long-term monitoring and investigation of the emm types and superantigen genes of GAS prevalence are imperative.

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“…(8%), and emm6 (7%) [31]. Furthermore, the isolates of emm60.1 and emm63.0 genotypes were prevalent in the children from the villages of Guizhou Province in China, which led to the outbreak of acute glomerulonephritis in 2005 [39].…”

Section: Discussionmentioning

confidence: 99%

Molecular epidemiology and antimicrobial resistance of group A streptococcus recovered from patients in Beijing, China

Zhang

Zhao

et al. 2020

Preprint

View full text Add to dashboard Cite

Background: Group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern. The objective of this study was to investigate the molecular epidemiological characteristics and antimicrobial resistance of GAS isolates from patients in Children's Hospital in Beijing. Methods: From 2016 to 2017, pharyngeal swab samples were collected from the outpatients in Children's Hospital, Capital Institute of Pediatrics, who were diagnosed with scarlet fever. Antimicrobial susceptibility test was performed according to the distribution of conventional antibiotics and Clinical and Laboratory Standards Institute (CLSI) recommendations. The distribution of the macrolide-resistance genes ( ermB, ermA, mefA ), emm (M protein-coding gene) typing, and superantigens (SAg) gene profiling were examined by polymerase chain reaction (PCR). Results: A total of 297 GAS strains were collected. The susceptibility of the strains to penicillin, ceftriaxone, and levofloxacin was 100%. The rate of antimicrobial resistance to erythromycin and clindamycin was 98.3% and 96.6%, respectively. The dominant emm types were Streptococcus pyogenes (Lancefield group A streptococcus; GAS) is a major pathogen causing infectious diseases in children. It causes suppurative and non-suppurative diseases, such as erysipelas, suppurative tonsillitis, scarlet fever, rheumatic fever, and glomerulonephritis [1]. Globally, there are about 616 million cases of GAS pharyngitis every year, among which, 17,800 cases are new infections, and about 517,000 patients with severe GAS are deceased every year [2]. Recently, the positive rate of GAS was estimated at 21.2% in the pharyngeal culture of patients diagnosed as "streptococcal infection/tonsillitis/angina" [3]. Moreover, the incidence of streptococcal pharyngitis is common in children aged 0-14 years. From 2012 to 2014, the average number of positive cases of streptococcal culture was 2685.1/100,000 children in Beijing, including 1652.7 outpatient visits [4]. In 2011, scarlet fever broke out in mainland China and Hong Kong, with a sharp increase in incidence [5,6]. Penicillin is the preferred clinical treatment of GAS infection, while erythromycin is the first alternative antibiotic for patients allergic to penicillin, followed by clindamycin. The drug resistance rate to macrolides, used as alternative antibiotics, is gradually increasing, which might be related to the overuse of such antibiotics [7,8]. In our previous study, 95 isolates were recovered from suppurative tonsillitis, acute glomerulonephritis, scarlet fever and streptococcal dermatitis. The resistance rates of the isolates to erythromycin, clindamycin and tetracycline were 98.9%, 100%, 94.7% respectively [9] .The M protein encoded by the emm gene is the main pathogenic factor of GAS, and different types vary in pathogenicity. Therefore, emm typing is employed to track outbreak and routinely mo...

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Changes in emm types and superantigen gene content of Streptococcus pyogenes causing invasive infections in Portugal

Cited by 22 publications

References 40 publications

Distribution of virulence genes and the molecular epidemiology of Streptococcus pyogenes clinical isolates by emm and multilocus sequence typing methods

Distribution of virulence genes and the molecular epidemiology of Streptococcus pyogenes clinical isolates by emm and multilocus sequence typing methods

Molecular epidemiology and antimicrobial resistance of group A streptococcus recovered from patients in Beijing, China

Molecular epidemiology and antimicrobial resistance of group A streptococcus recovered from patients in Beijing, China

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