Streptococcal pharyngitis and rheumatic heart disease: the superantigen hypothesis revisited.

Group A Beta Hemolytic Streptococci (GAS) is the most critical human pathogen that leads to tonsillopharyngitis. The aims of this study were to identify GAS isolates and to determine emm typing, the coverage rate of available vaccines, and the distribution of superantigen gene profiles. 15 GAS isolates were isolated from throat cultures of 200 patients with tonsillopharyngitis, who were admitted to Canakkale Health Application and Research Hospital between October 2017 and May 2018. Identification of the isolates was performed by conventional methods and 16S rRNA sequence analysis. emm typing and exotoxin profiling of the isolates were performed by polymerase chain reaction. 7.5% GAS was detected in 200 patients. All the GAS isolates were identified as S. pyogenes. emm typing can be carried out in 13 S. pyogenes isolates. emm89 (33.3%), emm44 (20%), emm6 (13.3%), emm84 (6.7%), emm1 (6.7%), and emm18.1 (6.7%) were found to be six emm types. The coverage rate of S. pyogenes strains for 26-valent vaccine was 61.5% and for the 30-valent vaccine 84.6%. The most common exotoxin was speB (86.7%), followed by speC (60%), speF (33.3%), ssa (26.7%), speA (20%), speM (20%), speJ (13.3%), speL (6.7%), and speI (6.7%). As a result of determining the emm types of S. pyogenes species in Canakkale, it was concluded that the potential of 30-valent vaccine should be considered in Turkey and development of vaccines containing exotoxin types may be beneficial.

/pdf/detection-of-group-a-beta-hemolytic-streptococci-species-emm-3rpdc8t4r9.pdf

Detection of Group A Beta Hemolytic Streptococci Species, emm , and Exotoxin Genes Isolated from Patients with Tonsillopharyngitis

Objectives The aim of this review was to provide an updated scenario on the epidemiology of group A streptococci (GAS) in the Middle East and North Africa (MENA) region with a special spotlight on the most prevalent emm  types and macrolide resistance profiles. Methods This review briefly summarises the disease burden for GAS in the MENA region. Results Whilst the burden of invasive GAS infections is difficult to assess in the MENA region, the GAS prevalence ranged from 2.5% up to 42.4% in pharyngitis patients and from 2.4% up to 35.4% in healthy carriers.  emm1, emm12, emm89, emm4, emm28 and emm3  were responsible for the major GAS burden in the MENA region. The coverage rate of the new M protein-based vaccine candidate (30-valent) varied from 42% to 100% according to the country. The rate of erythromycin resistance differed substantially between countries from low to moderate or high. Conclusion These data add more shreds of evidence on the neglected GAS burden in the MENA region. Systematic surveillance of invasive GAS infections along with molecular characterisation of GAS isolates are strongly recommended to track the trends of circulating clones and to evaluate the potential coverage of vaccine candidates.

Distribution of emm types and macrolide resistance determinants among group A streptococci in the Middle East and North Africa region.

Group A streptococci are important pathogens with various virulence factors, such as M protein, superantigens, hemolysins, deoxyribonuclease, and proteases. The aims of this study are to investigate the detection of emm genotypes and other virulence genes, such as SAgs, DNase, protease, antibiotic resistance, and phylogenetic relationships in GAS strains isolated from clinical samples.Test strains were obtained from Çukurova University Balcalı Hospital and regional hospitals in Adana province. The M proteins were detected by sequence analysis of emm genes. SAgs and other virulence gene profiles were determined using the Multiplex-PCR method. The antibiotic susceptibility of the isolates was performed by the disc diffusion method and evaluated according to CLSI criteria. The PFGE method was used to determine the clonal relationship between the strains.The emm gene was positive in 86 isolates. The most common emm genotypes were emm28 (22%), emm1 (18.6%), emm12 (13.9%), and emm3 (11.6%). Also, the most common virulence genes were speG (58.1%), speC (56.9%), sdaB (53.4%), and mac (53.4%). The rates of resistance to erythromycin, clindamycin, levofloxacin, ciprofloxacin and telithromycin were 19.8%, 16.3%, 4.7%, 3.5%, and 3.5%, respectively.As a result, additional regional studies on the detection and prevalence of GAS virulence factors in Turkey are required. We believe that this study will provide valuable information for epidemiological studies on emm sequences, Sags, and other virulence factors of Streptococcus pyogenes in Turkey.

Distribution of emm, superantigen and other virulence genotypes and detection of phylogenetic relationships in group A streptococcal isolates.

Abstract Objective The aim of this study is to evaluate echocardiographic evidence of latent rheumatic heart disease and Group A β hemolytic Streptococcus carriage in family members of acute rheumatic fever patients and asses the importance of screening for this conditions. Methods Children with diagnosis of acute rheumatic fever aged between 5 and 18 years and their family members and household relatives were screened with echocardiography for latent rheumatic heart disease and Group A β hemolytic Streptococcus carriage with throat culture test. Results In the study period, 46 index cases and their 124 relatives were evaluated. Echocardiographic screening of 22 (17.7%) family members revealed latent rheumatic heart disease.Ten (8.1%) cases had positive throat culture results for Group A β hemolytic Streptococcus and 2 of them, 20% of all culture positive cases, had latent rheumatic heart disease findings in echocardiographic evaluation. Conclusions The family members of children with rheumatic heart disease have increased relative risk for rheumatic heart disease. Screening programs for throat culture test and echocardiographic evaluation of household, family members and relatives, of children with acute rheumatic fever should be planned for determination of definite or latent rheumatic heart disease and asymptomatic Streptococcal throat carriage and if detected, Group A β hemolytic Streptococcal carriage should be treated to decrease the risk of recurrent acute rheumatic fever for index case. 

Screening of Latent Rheumatic Heart Disease and Pharyngeal Group a Streptococci Carriage in Family Members of Children With Rheumatic Heart Disease

M-protein and pyrogenic toxins are the most important virulence factors of Streptococcus pyogenes, and they play significant role in the pathophysiology of acute rheumatoid fever and scarlet fever, respectively. In this study, the pharyngeal carriage of S.pyogenes of the primary school children, clonal relationship of the strains, M-protein types, and the presence of pyrogenic toxin genes were aimed to be investigated. A total of 668 throat cultures obtained from children (age range: 6-16 years) in two primary schools in our region, were included in the study. The clonal relationships of the isolated group A streptococci (GAS) strains were investigated by DiversiLab assay (BioMerieux, France), and the clonal relatedness was confirmed by pulsed-field gel electrophoresis (PFGE) method. M-protein (emm) typing was performed by DNA sequencing as suggested by Centers for Disease Control and Prevention (CDC). The genes encoding pyrogenic toxins, speA and speC, were investigated by an in-house multiplex polymerase chain reaction (PCR) method. S.pyogenes was isolated from 134 (20.05%) of the throat samples. The GAS carriage rate of the students aged ≥10 was statistically higher than those 7-9 years age group (%22 vs %16.4, p<0.05). The M protein gene could be characterized only among 123 isolates by DNA sequencing, and 20 different emm types were detected. The most frequent emm type was emm1 (n=38, 30.9%) followed by emm12 (n=18, 14.6%), emm89 (n=10, 8.1%), emm118 (n=9, 7.3%), and emm4 (n=7, 5.7%). Pyrogenic toxin genes were found in 25 (18.6%) of the isolates, including speA in 11 isolates (8.2%) and speC in 12 isolates (8.9%) and both genes were detected in 2 isolates (1.5%). Sixty-two different Rep (Repetitive extragenic palindromic)-PCR profiles were detected in 134 S.pyogenes isolates by DiversiLab method. Thirteen different clusters were formed by a total of clonally related 36 isolates revealing a strain clustering ratio of 26.9%. Clonal relationship of all isolates in the same cluster was confirmed by PFGE method. In this study, relatively high percentage of GAS carriage was observed among primary school children in our region. The coverage rate of the 30-valent vaccine was determined to be over 90% with respect to M-protein types. Since the pyrogenic toxin-encoding genes were found in one fifth of the isolates from the studied subjects, we concluded that the carrier population may also have high risk for scarlet fever. We also concluded that, the clonal relationship ratio determined among the isolates may be a risk in school transmission of GAS.

/pdf/carriage-of-streptococcus-pyogenes-in-primary-school-2cel3iovkk.pdf

[Carriage of Streptococcus pyogenes in primary school children: M-protein types, pyrogenic toxin genes, and investigation of the clonal relationships between the isolates].

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[Carriage of Streptococcus pyogenes in primary school children: M-protein types, pyrogenic toxin genes, and investigation of the clonal relationships between the isolates].