emm gene diversity, superantigen gene profiles and presence of SlaA among clinical isolates of group A, C and G streptococci from western Norway

Streptococcus dysgalactiae subsp. equisimilis infection and its intersection with Streptococcus pyogenes

SUMMARYStreptococcus dysgalactiae subsp. equisimilis (SDSE) is an increasingly recognized cause of disease in humans. Disease manifestations range from non-invasive superficial skin and soft tissue infections to life-threatening streptococcal toxic shock syndrome and necrotizing fasciitis. Invasive disease is usually associated with co-morbidities, immunosuppression, and advancing age. The crude incidence of invasive disease approaches that of the closely related pathogen, Streptococcus pyogenes. Genomic epidemiology using whole-genome sequencing has revealed important insights into global SDSE population dynamics including emerging lineages and spread of anti-microbial resistance. It has also complemented observations of overlapping pathobiology between SDSE and S. pyogenes, including shared virulence factors and mobile gene content, potentially underlying shared pathogen phenotypes. This review provides an overview of the clinical and genomic epidemiology, disease manifestations, treatment, and virulence determinants of human infections with SDSE with a particular focus on its overlap with S. pyogenes. In doing so, we highlight the importance of understanding the overlap of SDSE and S. pyogenes to inform surveillance and disease control strategies.

Presence of Group A streptococcus frequently assayed virulence genes in invasive disease: a systematic review and meta-analysis

Introduction

It is currently unclear what the role of Group A streptococcus (GAS) virulence factors (VFs) is in contributing to the invasive potential of GAS. This work investigated the evidence for the association of GAS VFs with invasive disease.

Methods

We employed a broad search strategy for studies reporting the presence of GAS VFs in invasive and non-invasive GAS disease. Data were independently extracted by two reviewers, quality assessed, and meta-analyzed using Stata®.

Results

A total of 32 studies reported on 45 putative virulence factors [invasive (n = 3,236); non-invasive (n = 5,218)], characterized by polymerase chain reaction (PCR) (n = 30) and whole-genome sequencing (WGS) (n = 2). The risk of bias was rated as low and moderate, in 23 and 9 studies, respectively. Meta-,analyses of high-quality studies (n = 23) revealed a significant association of speM [OR, 1.64 (95%CI, 1.06; 2.52)] with invasive infection. Meta-analysis of WGS studies demonstrated a significant association of hasA [OR, 1.91 (95%CI, 1.36; 2.67)] and speG [OR, 2.83 (95%CI, 1.63; 4.92)] with invasive GAS (iGAS). Meta-analysis of PCR studies indicated a significant association of speA [OR, 1.59 (95%CI, 1.10; 2.30)] and speK [OR, 2.95 (95%CI, 1.81; 4.80)] with invasive infection. A significant inverse association was observed between prtf1 [OR, 0.42 (95%CI, 0.20; 0.87)] and invasive infection.

Conclusion

This systematic review and genomic meta-analysis provides evidence of a statistically significant association with invasive infection for the hasA gene, while smeZ, ssa, pnga3, sda1, sic, and NaDase show statistically significantly inverse associations with invasive infection. SpeA, speK, and speG are associated with GAS virulence; however, it is unclear if they are markers of invasive infection. This work could possibly aid in developing preventative strategies.

Genomic epidemiology of Streptococcus dysgalactiae subsp. equisimilis strains causing invasive disease in Norway during 2018

Background

Streptococcus dysgalactiae subspecies equisimilis (SDSE) is an emerging global pathogen, yet the epidemiology and population genetics of SDSE species have not been extensively characterized.

Methods

We carried out whole genome sequencing to characterize 274 SDSE isolates causing bloodstream infections obtained through national surveillance program in 2018. We conducted multilocus sequence typing (MLST), emm-typing, core genome phylogeny, as well as investigated key features associated with virulence. Moreover, comparison to SDSE from other geographic regions were performed in order to gain more insight in the evolutionary dynamics in SDSE.

Results

The phylogenetic analysis indicated a substantial diversity of emm-types and sequence types (STs). Briefly, 17 emm-types and 58 STs were identified that formed 10 clonal complexes (CCs). The predominant ST-types were ST20 (20%), ST17 (17%), and ST29 (11%). While CC17 and CC29 clades showed a substantial heterogeneity with well-separated emm-associated subclades, the CC20 clade harboring the stG62647 emm-type was more homogenous and the most prevalent in the present study. Moreover, we observed notable differences in the distribution of clades within Norway, as well as several disseminated CCs and also distinct geographic variations when compared to data from other countries. We also revealed extensive intra-species recombination events involving surface exposed virulence factors, including the emm gene important for phylogenetic profiling.

Conclusion

Recombination events involving the emm as well as other virulence genes in SDSE, are important mechanisms in shaping the genetic variability in the SDSE population, potentially offering selective advantages to certain lineages. The enhanced phylogenetic resolution offered by whole genome sequencing is necessary to identify and delimitate outbreaks, monitor and properly characterize emerging strains, as well as elucidate bacterial population dynamics.

Neglected gut microbiome: interactions of the non-bacterial gut microbiota with enteric pathogens

A diverse array of commensal microorganisms inhabits the human intestinal tract. The most abundant and most studied members of this microbial community are undoubtedly bacteria. Their important role in gut physiology, defense against pathogens, and immune system education has been well documented over the last decades. However, the gut microbiome is not restricted to bacteria. It encompasses the entire breadth of microbial life: viruses, archaea, fungi, protists, and parasitic worms can also be found in the gut. While less studied than bacteria, their divergent but important roles during health and disease have become increasingly more appreciated. This review focuses on these understudied members of the gut microbiome. We will detail the composition and development of these microbial communities and will specifically highlight their functional interactions with enteric pathogens, such as species of the family Enterobacteriaceae. The interactions can be direct through physical interactions, or indirect through secreted metabolites or modulation of the immune response. We will present general concepts and specific examples of how non-bacterial gut communities modulate bacterial pathogenesis and present an outlook for future gut microbiome research that includes these communities.

Streptococcus dysgalactiae subsp. equisimilis from invasive and non-invasive infections in Spain: combining epidemiology, molecular characterization, and genetic diversity

The purpose of this study was to characterize the antibiotic resistance, virulence, and genetic diversity among invasive and non-invasive Streptococcus dysgalactiae subsp. equisimilis (SDSE) isolates. SDSE were isolated from clinical samples of outpatients and inpatients cares in La Rioja region (Spain) during 2012-2015. The analyses performed were susceptibility testing by disc diffusion, resistance and virulence genes by PCR, emm typing by PCR and sequencing, and other molecular typing by SmaI-PFGE and MLST. Forty-two SDSE isolates were recovered (64.3% non-invasive, 35.7% invasive) that were grouped in 31 PFGE patterns, 17 ST, and 14 emm types, being stC1400, stG6792, and stG62647 the most frequent, and stC74a and stC5345 exclusive in invasive SDSE. Twenty-one SDSE were resistant to at least one antibiotic. The erm(TR) and erm(B) genes were linked with resistance to macrolides; tet(M) and tet(T) to tetracycline; dfrF to trimethoprim; ant(6)-Ia and aph(3')-IIIa to aminoglycosides; and the substitutions Asp80Ala in GyrA and Ser79Phe in ParC with resistance to levofloxacin. The sagA, slo, scpA, and ska virulence genes were amplified in 93% SDSE. Streptococcal superantigenic speG^dys gene was identified in 80% of invasive and 63% of non-invasive SDSE and correlated with certain emm types (e.g., stG62647 or stG6792). SDSE invasive infections were most frequent in elderly patients, and half of our SDSE were resistant to at least one antibiotic tested. This work is the first detection of tet(T), dfrF, and new substitution in GyrA protein in SDSE. A high diversity of circulating genetic lineages was found among our SDSE.

Molecular epidemiology of nonpharyngeal group A streptococci isolates in northern Lebanon

Aim: To characterize the epidemiology of group A Streptococcus (GAS) involved in nonpharyngeal infections sparingly addressed in Lebanon. Materials & methods: A collection of 63 nonpharyngeal GAS isolates recovered between 2010 and 2019 from northern Lebanon were analyzed through emm typing, virulence gene profiling, FCT typing and antibiotic susceptibility analysis. Results & conclusion: A total of 29 emm subtypes was detected, with emm1 being the most dominant. A great intraclonal divergence driven by the loss and gain of superantigens or by the structural variability within the FCT regions was unraveled. The resistance rates for erythromycin and tetracycline were 8 and 20.6%, respectively. The 30-valent vaccine coverage was 76%. This study evidences the complexity of the neglected GAS pathogen in Lebanon.

Prevalence and molecular diversity of invasive Streptococcus dysgalactiae and Streptococcus pyogenes in a German tertiary care medical centre

Prevalence of invasive ß-haemolytic streptococci (BHS) at a tertiary care hospital and molecular diversity of S. pyogenes and S. dysgalactiae was studied. Between 2012 and 2016, all blood culture sets (n = 55,839), CSF (n = 8413) and soft tissue (n = 20,926) samples were analysed for BHS positivity using HYBASE software. Molecular profiles of 99 S. pyogenes and S. dysgalactiae were identified by sequencing of M protein genes (emm types) and multiplex PCR typing of 20 other virulence determinants. Streptococci contributed to 6.2% of blood, 10.7% of CSF and 14.5% of soft tissue isolates, being among the most common invasive isolates. The overall rates of invasive S. pyogenes, S. agalactiae, S. dysgalactiae and S. pneumoniae were 2.4, 4.4, 2.1, and 5.3%. Whereas S. pneumoniae was 1.5% more common in CSF samples, BHS isolates were 2-fold and 11-fold higher in bacteraemia and invasive soft tissue infections. Genetic BHS typing revealed wide molecular diversity of invasive and noninvasive group A and group G BHS, whereas one emm-type (stG62647.0) and no other virulence determinants except scpA were detected in invasive group C BHS. BHS were important invasive pathogens, outpacing S. pneumoniae in bacteraemia and invasive soft tissue infections. The incidence of S. dysgalactiae infections was comparable to that of S. pyogenes even with less diversity of molecular virulence. The results of this study emphasise the need for awareness of BHS invasiveness in humans and the need to develop BHS prevention strategies.

Foodborne Outbreak of Group G Streptococcal Pharyngitis in a School Dormitory in Osaka, Japan

In September 2016, 140 patients with primary symptoms of sore throat and fever were identified in a school dormitory in Osaka, Japan. Epidemiological and laboratory investigations determined that these symptomatic conditions were from a foodborne outbreak of group G streptococcus (GGS), with GGS being isolated from samples from patients, cooks, and foods. The strain of GGS was identified as Streptococcus dysgalactiae subsp. equisimilis of two emm types (stG652.0 and stC36.0). The causative food, a broccoli salad, was contaminated with the two types of S. dysgalactiae subsp. equisimilis, totaling 1.3 × 10⁴ CFU/g. Pulsed-field gel electrophoresis (PFGE) of samples from patients, cooks, and foods produced similar band patterns among samples with the same emm type. This result suggested the possibility of exposure from the contaminated food. The average onset time was 44.9 h and the prevalence rate was 62%. This is the first report to identify the causative food of a foodborne outbreak by Streptococcus dysgalactiae subsp. equisimilis.

Emergence of a Streptococcus dysgalactiae subspecies equisimilis stG62647-lineage associated with severe clinical manifestations

Increasing incidence rates of invasive Streptococcus dysgalactiae subspecies equisimilis (SDSE) infections have been reported worldwide, but the evolutionary mechanisms underlying this development remain elusive. Through prospective surveillance of invasive SDSE infections in western Norway, we observed the emergence of a novel and virulent SDSE genotype, stG62647. This emm-type, rarely encountered as a cause of invasive disease during 1999–2012, emerged in 2013 as the predominant SDSE-genotype. The stG62647-infections were associated with an aggressive clinical course, including the occurrence of streptococcal toxic shock syndrome, necrotizing soft-tissue infections and endocarditis. All the invasive stG62647-isolates were subjected to whole genome sequencing, attempting to explore the genetic events underpinning its epidemicity. Although 10% of the genomes was unique for stG62647-genotype, notably 18 out of 19 isolates contained a disrupted streptococcal invasive locus (sil) due to the insertion of a transposase, IS1548, into the silB-gene. We postulate that the virulence of stG6267-isolates could be partly attributable to the abrogation of the attenuating control normally exerted by this regulon, although experimental verification was not performed. To the best of our knowledge, this is the first study employing large scale whole genome sequencing to illuminate the genetic landscape of epidemic lineages in SDSE.

Prevalence of M75 Streptococcus pyogenes Strains Harboring slaA Gene in Patients Affected by Pediatric Obstructive Sleep Apnea Syndrome in Central Italy

Recently we reported an association between pediatric obstructive sleep apnea syndrome (OSAS) and Group A streptococcus (GAS) sub-acute chronic tonsil colonization. We showed that GAS may contribute to tonsil hyperplasia via a streptolysin O (SLO)-dependent cysteinyl leukotrienes (CysLTs) production, which can trigger T and B cell proliferation. In the present study, we characterized the GAS strains isolated from pediatric OSAS patients in comparison with a panel of age and sex matched GAS strains unrelated to OSAS, but isolated in the same area and during the same period ranging from 2009 to 2013. We found that slaA gene, previously reported to be associated to CysLTs production pathway, was significantly associated to GAS OSAS strains. Moreover, the most numerous group (32%) of the GAS OSAS strains belonged to M75 type, and 6 out of 7 of these strains harbored the slaA gene. Multilocus Sequence Typing (MLST) experiments demonstrated that the clone emm75/ST49/ smeZ, slaA was associated to OSAS cases. In conclusion, we found an association between slaA gene and the GAS OSAS strains, and we showed that the clone emm75/ST49 harboring genes smeZ and slaA was exclusively isolated from patients affected by OSAS, thus suggesting that this genotype might be associated to the pathogenesis of OSAS, although further studies are needed to elucidate the possible role of SlaA in tonsil hypertrophy development.

Molecular characterization and antibiotic resistance of clinical Streptococcus dysgalactiae subsp. equisimilis in Beijing, China

Streptococcus dysgalactiae subsp. equisimilis (SDSE) is presently considered as a human pathogen associated with clinical infection. We characterized 56 SDSE isolates collected from two tertiary hospitals in Beijing, China. Sixteen distinct emm types/subtypes were detected, dominated by stG245.0 (32.1%), stG652.0 (10.7%), stG6.1 (10.7%) and stG485.0 (10.7%), and a novel stG840.0 variant type was identified. All isolates possessed virulence genes of sagA and scpA, and most carried slo (98.2%), ska (98.2%) and speG(dys) (35.7%). By multilocus sequence typing (MLST) analysis, 17 individual sequence types (STs) were distinguished, including 7 newly-identified STs (26.8% of isolates), of which ST127 (30.4%), ST7 (12.5%) and ST44 (10.7%) dominated. Meanwhile, pulsed-field gel electrophoresis (PFGE) analysis revealed 33 pattern types (PTs), which were further combined into 16 pattern clusters (PCs), and 59.3% of isolates were distributed into 2 dominant PCs. Notably, emm types had both close relationship and consistency with STs and PFGE PCs. Furthermore, of 56 SDSE isolates, the predominant antibiotic resistances were erythromycin (71.4%), clindamycin (71.4%) and tetracycline (60.7%). Correspondingly, the prevalent resistance genes of macrolide and tetracycline were erm(B) (78.6%) and tet(M) (73.2%). In addition, multiple point mutations of parC, one of fluoroquinolone resistance genes, were observed (accounting for 75%), and were divided into 12 types, with parC 07 as the predominant type. Our data suggested the wide molecular diversity and distinctive regional features of SDSE from clinical infection in Beijing, China.

Prevalence of emm types and antimicrobial susceptibility of Streptococcus dysgalactiae subsp. equisimilis in Austria

OBJECTIVES

An increase of severe infections caused by Streptococcus dysgalactiae subsp. equisimilis (SDSE) similar to infections caused by Streptococcus pyogenes has been reported over the last years. Little is known about infections with SDSE in Austria. Therefore, we investigated a collection of 113 SDSE invasive and non-invasive isolates from different infection sites and type of infections as well as patients' characteristics.

METHODS

The isolates were phenotypically identified and emm typed using the enlarged emm database from the Centers for Disease Control and Prevention. Additionally, 13 antimicrobial agents were tested using EUCAST guidelines and virulence genes were investigated.

RESULTS

Severe SDSE infections were most common in elderly men with underlying diseases especially diabetes mellitus. With VitekMS identification of SDSE isolates was successful to the species level only. Emm typing revealed 24 different emm types, one new type and one new subtype. StG485, stG6, stC74a, stG643, and stG480 were the predominant types in this study, stC74a and stG652 in invasive infections and stG643, stC74a and stG485 in non-invasive infections. Resistance was observed to tetracycline (62%), macrolides (13%) with one M phenotype, and clindamycin (12%) presenting 6 constitutive MLS(B) phenotypes and 8 inducible MLS(B) phenotypes. Levofloxacin resistance was detected only in one isolate. All isolates tested for virulence genes were positive for scpA, ska, saga and slo. Superantigenic genes were negative except speG(dys) (positive 17/34; 50%).

CONCLUSION

This paper presents the first report of SDSE infections in Austria. Severe SDSE infections were found mainly in elderly men with underlying diseases. SDSE isolates demonstrated substantial emm type diversity without association with infections site or invasiveness. Analysis of virulence genes showed no significant difference between invasive and non-invasive infections.

Beta-haemolytic group A, C and G streptococcal infections in Western Norway: a 15-year retrospective survey

Pyogenic streptococci cause significant morbidity and mortality, and the incidence of invasive group C and G streptococcal disease appears to be increasing. In this retrospective study we describe the epidemiological characteristics of invasive group A, C and G, along with non-invasive group C and G streptococcal infections in Western Norway from 1999 to 2013. A total of 512 invasive streptococcal infections were identified, of these 297 (58%) were group A (GAS), 24 (5%) group C (GCS) and 188 (37%) group G streptococci (GGS). In the non-invasive group, 4935 GCS and GGS-infections were identified. GCS and GGS were treated as one group (GCGS) for statistical purposes. All microbial categories displayed increasing incidence with age, seasonal variation and a male predominance. The incidence of invasive GCGS infections increased significantly from 1.4/100,000 inhabitants in 1999 to 6.3/100,000 in 2013 (p <0.001). Conversely, the annual rates of invasive GAS infection exhibited marked fluctuations, ranging from 2.7/100,000 (2000) to 8.3/100,000 (1999), but no significant temporal trends were observed. The incidence of non-invasive GCGS infections decreased significantly during the study period (p <0.001). The most frequently encountered emm-types among the 209 iGAS-isolates analysed were emm1 (24%), emm3 (14%) and emm28 (14%); whereas stG643 (19%), stG485 (15%) and stG6 (13%) were most prevalent among the 122 iGCGS-isolates available for typing. The increasing burden of invasive β-haemolytic streptococcal disease in our community calls for sustained attentiveness to the clinical and molecular aspects of GAS, GCS and GGS infections.

Current views of haemolytic streptococcal pathogenesis

PURPOSE OF REVIEW

Increasing disease caused by beta-haemolytic streptococci indicates the need for improved understanding of pathogenesis.

RECENT FINDINGS

Streptococcus pyogenes, or group A Streptococcus (GAS), causes significant disease worldwide. The closely related Streptococcus dysgalactiae subspecies equisimilis (SDSE) is increasingly recognized as causing a similar disease spectrum. Whole-genome sequencing applied to the study of outbreaks may reveal factors that contribute to pathogenesis and changes in epidemiology. The role of quorum sensing in biofilm formation, and interspecies communication with other streptococci, is discussed. GAS has evolved multiple mechanisms to evade the humoral arm of innate immunity, including complement, which is well known in protecting the host from bacteria, and the coagulation-fibrinolytic system, which is increasingly recognized as an innate immune effector.

SUMMARY

Molecular biology has enhanced our understanding of the intricate balance of host-pathogen interactions that result in clearance or establishment of invasive streptococcal infection. Although the skin and oropharynx remain the usual ecological niche of GAS and SDSE, occasionally the bacteria find themselves within deeper tissues and blood. Recent research has armed us with better knowledge of bacterial adaptations to this alternative environment. However, the challenge is to translate this knowledge into clinical practice, through the development of novel therapeutic options and ultimately a vaccine against GAS.

Beta-hemolytic streptococcal infections in trauma patients

PURPOSE

β-hemolytic streptococci (βHS) causes a diverse array of human infections. The molecular epidemiology of β-hemolytic streptococcal infections in trauma patients has not been studied. This study reports the molecular and clinical epidemiology of β-hemolytic streptococcal infections at a level 1 trauma centre of India.

METHODS

A total of 117 isolates of βHS were recovered from clinical samples of trauma patients. The isolates were identified to species level and subjected to antimicrobial susceptibility testing. Polymerase chain reaction (PCR) assay was done to detect exotoxin virulence genes. The M protein gene (emm gene) types of GAS strains were ascertained by sequencing.

RESULTS

Group A Streptococcus (GAS) was the most common isolate (64 %), followed by group G Streptococcus (23 %). A large proportion of GAS produced speB (99 %), smeZ (91 %), speF (95 %) and speG (87 %). smeZ was produced by 22 % of GGS. A total of 25 different emm types/subtypes were seen in GAS, with emm 11 being the most common. Resistance to tetracycline (69 %) and erythromycin (33 %) was commonly seen in GAS.

CONCLUSIONS

β-hemolytic streptococcal infections in Indian trauma patients are caused by GAS and non-GAS strains alike. A high diversity of emm types was seen in GAS isolates, with high macrolide and tetracycline resistance. SpeA was less commonly seen in Indian GAS isolates. There was no association between disease severity and exotoxin gene production.

Streptococcus dysgalactiae subsp. equisimilis bacteremia: an emerging infection

The importance of group C and G Streptococcus dysgalactiae subspecies equisimilis (S. dysgalactiae subsp. equisimilis) as a significant pathogen has recently been better recognized. S. dysgalactiae subsp. equisimilis disease can range in severity from milder skin and soft-tissue conditions such as wound infection, erysipelas, and cellulitis, to life-threatening necrotizing fasciitis and streptococcal toxic shock syndrome, thus sharing the clinical picture with S. pyogenes. The most common clinical manifestation of bacteremia is cellulitis. An increase in the incidence of S. dysgalactiae subsp. equisimilis bacteremia has been recognized. Invasive forms of this infection are most commonly found in elderly patients with underlying comorbidities and skin breakdown. The case fatality in bacteremia has been reported to be 15-18%. In this review, the epidemiology, clinical characteristics, and emm types of S. dysgalactiae subsp. equisimilis bacteremia are summarized.

Antibiotic susceptibilities, streptococcal pyrogenic exotoxin gene profiles among clinical isolates of group C or G Streptococcus dysgalactiae subsp. equisimilis & of group G S. anginosus group at a tertiary care centre

BACKGROUND & OBJECTIVES

Group C and group G streptococci (together GCGS) are often regarded as commensal bacteria and their role in streptococcal disease burden is under-recognized. While reports of recovery of GCGS from normally sterile body sites are increasing, their resistance to macrolides, fluoroquinolone further warrants all invasive β haemolytic streptococci to be identified to the species level and accurately tested for antimicrobial susceptibility. This study was aimed to determine the prevalence, clinical profile, antimicrobial susceptibility and streptococcal pyrogenic exotoxin gene profile (speA, speB, speC, speF, smeZ, speI, speM, speG, speH and ssa) of GCGS obtained over a period of two years at a tertiary care centre from north India.

METHODS

The clinical samples were processed as per standard microbiological techniques. β-haemolytic streptococci (BHS) were characterized and grouped. Antimicrobial susceptibility of GCGS was performed using disk diffusion method. All GCGS were characterized for the presence of streptococcal pyrogenic exotoxins (spe) and spe genes were amplified by PCR method.

RESULTS

GCGS (23 GGS, 2GCS) comprised 16 per cent of β haemolytic streptococci (25/142 βHS, 16%) isolated over the study period. Of the 25 GCGS, 22 (88%) were recovered from pus, two (8%) from respiratory tract, whereas one isolate was recovered from blood of a fatal case of septicaemia. Of the total 23 GGS isolates, 18 (78%) were identified as Streptococcus dysgalactiae subsp equisimilis (SDSE, large-colony phenotype), five (21%) were Streptococcus anginosus group (SAG, small-colony phenotype). The two GCS were identified as SDSE. All GCGS isolates were susceptible to penicillin, vancomycin, and linezolid. Tetracycline resistance was noted in 50 per cent of SDSE isolates. The rates of macrolide and fluoroquinolone resistance in SDSE were low. Twelve of the 20 SDSE isolates were positive for one or more spe genes, with five of the SDSE isolates simultaneously carrying speA+ speB+ smeZ+ speF or speB+ smeZ+speF, speI+speM+speG+speH or, speI+spe M+speH or speA+ speB+ speC+ smeZ+ speF. One notable finding was the presence of spe B in four of the five isolates of the Streptococcus anginosus group. No isolate was positive for ssa.

INTERPRETATION & CONCLUSIONS

Our study showed no association between GCGS isolates harbouring streptococcal pyrogenic exotoxins and disease severity. This might be attributed to the small sample size of spe-positive isolates.

Sequence diversity of sicG among group C and G Streptococcus dysgalactiae subspecies equisimilis isolates associated with human infections in western Norway

Streptococcal inhibitor of complement (SIC) and distantly related to SIC (DRS) are well-characterized extracellular virulence factors produced by only a few emm types among group A streptococci. The prevalence and sequence variations of the sic-like gene (sicG) in clinical samples of group C and G Streptococcus dysgalactiae subspecies equisimilis (SDSE), however, have not been widely investigated. We constructed primers targeting sicG and screened 129 geographically matched and previously emm-typed non-invasive (n = 64) and invasive (n = 65) SDSE isolates for the presence of this gene. sicG was detected in seven non-invasive and eight invasive isolates belonging to eight different emm types. Within five of these emm types, sicG-negative isolates were also detected. All three isolates of stG2078.0 possessed sicG and were associated with severe soft tissue infections. Altogether, six sicG alleles (sicG1-6) were identified, and sequence variations were mainly caused by single nucleotide polymorphisms and deletion/insertion mutations. sicG1-6 were predicted to encode SICG proteins of varying length, composition, and homology with SIC and DRS proteins of group A streptococci. Our findings indicate an unpredictable association between sicG and emm type, a limited distribution and substantial sequence diversity of sicG, and no obvious relation between its presence and disease severity.

Adult invasive and noninvasive infections due to Streptococcus dysgalactiae subsp. equisimilis in France from 2006 to 2010

We characterized 182 Streptococcus dysgalactiae subsp. equisimilis isolates and analyzed the epidemiological data on the corresponding infections. stG6, stG485, and stG6792 were the 3 most prevalent invasive emm types among the 27 different emm types recovered. High rates of antimicrobial resistance were observed for macrolides (26.4%) and tetracycline (34.6%).

Prevalence of β-hemolytic Streptococcus in children with special health care needs

Pharyngotonsillitis by β-hemolytic Streptococcus mostly affects children and immunocompromised, being Streptococcus pyogenes (Group A) the most common agent in bacterial pharyngotonsillitis.

AIM

This work targeted the research of β-hemolytic Streptococcus Group-A (SBHGA) and No-A (SBHGNA) in the oropharynx of individuals with special health needs from the APAE (Maceió-AL).

METHOD

A prospective study with oropharynx samples from patients with Down syndrome and other mental disorders (test) and students from a private school (control) aged 5-15 years. Cultures in blood agar (5%) were identified through Gram/catalase tests and bacitracin/trimethoprim-sulfamethoxazole disk diffusion method, applying the chi-squared statistical analysis.

RESULTS

A total of 222 bacterial colonies were isolated in 74 individuals from APAE and 65 in the control group. In the test group, previous episodes of pharyngotonsillitis were reported by 36.49% (27/74) and 9.46% (7/74) were diagnosed with symptoms and/or signs suggestive of oropharynx infection. No positive sample of S. pyogenes was confirmed at APAE, being all samples classified as SBHGNA, with 5 SBHGA in the control group.

CONCLUSION

The early identification of β-hemolytic Streptococcus is important for the fast treatment of pharyngotonsillitis and the absence of S. pyogenes avoid future suppurative or not-suppurative sequels in the group from APAE.