Invasive group A streptococcal infection in children: clinical manifestations and molecular characterization in a French pediatric tertiary care center

Global Streptococcus pyogenes strain diversity, disease associations, and implications for vaccine development: a systematic review

The high strain diversity of Streptococcus pyogenes serves as a major obstacle to vaccine development against this leading global pathogen. We did a systematic review of studies in PubMed, MEDLINE, and Embase that reported the global distribution of S pyogenes emm-types and emm-clusters from Jan 1, 1990, to Feb 23, 2023. 212 datasets were included from 55 countries, encompassing 74 468 bacterial isolates belonging to 211 emm-types. Globally, an inverse correlation was observed between strain diversity and the UNDP Human Development Index (HDI; r=-0·72; p<0·0001), which remained consistent upon subanalysis by global region and site of infection. Greater strain diversity was associated with a lower HDI, suggesting the role of social determinants in diseases caused by S pyogenes. We used a population-weighted analysis to adjust for the disproportionate number of epidemiological studies from high-income countries and identified 15 key representative isolates as vaccine targets. Strong strain type associations were observed between the site of infection (invasive, skin, and throat) and several streptococcal lineages. In conclusion, the development of a truly global vaccine to reduce the immense burden of diseases caused by S pyogenes should consider the multidimensional diversity of the pathogen, including its social and environmental context, and not merely its geographical distribution.

Bacterial biofilm in adenoids of children with chronic otitis media. Part II: a case-control study of nasopharyngeal microbiota, virulence, and resistance of biofilms in adenoids

Background: We previously described that adenoid tissue in children with chronic otitis media (COM) contained more mucosal biofilms than adenoid tissue removed for hypertrophy.Aims/objectives: The aim of the second part was to characterize nasopharyngeal microbiota and explore virulence of the most common middle ear pathogens.Material and methods: Bacteriological analysis was performed following a culture-based approach on the samples recovered from 30 patients of COM group (15 biofilm-positive and 15 biofilm-negative) and from 30 patients of a control group (15 biofilm-positive and 15 biofilm-negative). Virulence factors of Streptococcus pneumoniae, Streptococcus pyogenes, and Haemophilus influenzae were investigated.Results: The most frequent species were Firmicutes followed by Proteobacteria and Actinobacteria. The presence of biofilm was statistically associated with an increase of the number of bacterial species and Firmicutes phylum regardless of the condition (case/control). No virulence factors associated with invasive isolates were found for the most common middle ear pathogens.Conclusions and significance: This case-control study demonstrated that the presence of COM plus biofilm was associated with a given microbiota which contained more Firmicutes. Our study allows a better understanding of physiopathological mechanisms involved in chronic otitis media and paves the way for further investigations.

Molecular Characterization of Streptococcus pyogenes Causing Invasive Disease in Pediatric Population in Spain A 12-year Study

OBJECTIVES

To perform a comprehensive description of the epidemiology of Streptococcus pyogenes invasive disease in the pediatric population in 2 regions of Spain (Catalonia and Gipuzkoa) through 12 years.

METHODS

All S. pyogenes isolates causing invasive disease in pediatric patients between 2005 and 2016 were included. The emm-type and the presence of 13 exotoxin genes (speA, speB, speC, speF, speG, speH, speI, speJ, speK, speL, speM, smeZ, ssa and slo) were determined in all 93 available isolates and the Multi Locus Sequece Typing in 10% of isolates of each different emm-type.

RESULTS

Overall, 103 cases of S. pyogenes invasive infections were detected: 77 in Catalonia and 26 in Gipuzkoa, being 50.5% females. The incidence rate per 100,000 children was 2.5 for Gipuzkoa and 2.6 for Catalonia, with no significant temporal trends. The median age was 30 months. The most frequent clinical presentations were: pneumonia (26.2%), bacteremia/sepsis (23.3%), septic arthritis/osteomyelitis (22.3%), cellulitis/mastoiditis (12.6%) and meningitis (6.8%). Eight children developed streptococcal toxic shock syndrome. Nine cases were preceded by varicella infection. The associated mortality rate was 3.9%. Three isolates were resistant to erythromycin, being one of them also resistant to clindamycin and 4 isolates were resistant to levofloxacine. Forteen different emm-types were detected being emm1/ST28 (40.9%) the most frequent clone in both regions followed by emm12/ST36-ST242, emm6/ST382, emm3/ST15, emm75/ST150 and emm4/ST38-39. speA gene was only detected in emm1 and emm3 isolates. Eight exotoxins were enough to assign an emm-type with a very high degree of accuracy (95%). The 30-valent vaccine would include 96.8% of isolates.

[Invasive disease due to Streptococcus pyogenes: Changes in incidence and prognostic factors]

INTRODUCTION

Invasive group A streptococcal disease (iGASD) is a serious infection in children. Several studies have shown an increased incidence in the past years.

OBJECTIVE

To evaluate the characteristics and outcome of iGASD in children, and to determine changes in incidence or severity.

MATERIAL AND METHODS

A retrospective study was conducted on children≤16 years evaluated in a tertiary paediatric hospital in Madrid, and diagnosed with iGASD (June 2005-July 2013). An analysis was made of the demographics, symptomatology, microbiology, and treatment. The changes throughout the period studied were evaluated, as well as parameters associated with disease severity.

RESULTS

The study included a total of 55 children with iGASD, with 33 (60%) females, and a median age of 48.5 (20.5-88.9) months. The most frequent clinical syndromes were cellulitis/subcutaneous abscess (21.8%), ENT abscess (20%), pneumonia (16.4%), osteoarticular infection (16.4%), and mastoiditis (12.7%). The incidence of iGASD (cases/10⁵ emergencies/year) increased from 5.6 (4.2-7.2) between June 2005-May 2009 to 18.9 (15.1-26) between June 2009-May 2013; P=.057. Surgery and admission to PICU was required by 35 (63.6%) and 10 (18.2%) patients, respectively. Children in PICU were younger (26.5 vs 52.6 months, P=.116), had a higher C-reactive protein (24.5 vs 10.7mg/dl, P<.001) and higher frequency of pneumonia (60 vs 7%, P<.001). In the multivariate analysis, only C-reactive protein was a risk factor for admission to PICU (OR: 1.14 [1.004-1.286], P=.04). There were no sequelae.

CONCLUSIONS

An increased incidence of iGASD was observed in the children in this study. Lower age, pneumonia, and higher C-reactive protein were associated with disease severity in this series.

Invasive disease by Streptococcus pyogenes: patients hospitalized for 6 years

INTRODUCTION AND OBJECTIVE

The last years an increase of severe cases of invasive disease (ID) due to Streptococcus pyogenes or streptococcus b-hemolytic group A (SGA) had been detected. The aim of this study was to analyze the epidemiology and the clinical features of ID due to SGA in a tertiary Pediatric Hospital.

MATERIAL AND METHODS

Retrospective study in a Pediatric hospital, of all in-patients with final diagnosis of ID due to SGA during 6 years (2009-2014). To consider ID, SGA had to be isolated in sterile samples; in patients with fascitis necroticans in skin samples or in any sample in patients with the diagnostic of Streptococcal Toxic Shock Syndrome (STSS). The SSTS was defined as hypotension and at least 2 of these criteria: renal failure, hepatic failure, acute respiratory distress, tissue necrosis or desquamative erythematous rash. Demographic data, type of infection, risk factors, clinical presentation, analytical data at admission, treatment, need for admission to a pediatric intensive care unit, microbiological data, hospital stay and evolution were collected.

RESULTS

Fifty-two (52) cases were included (12/10,000 of all inpatients); 3 years-old was the medium age (p25-75: 1.4-6.9 years); 28 (53.8%) were boys. Fourteen patients (26.9%) had risk factors. Fever was the major symptom (51 patients, 98.1%). The skin lesions were the most frequent clinical manifestations found (21; 40.4%). In 50 (96%) cases, SGA was isolated in at least one sterile sample. Skin and soft tissue infections were diagnosed in 14 patients (26.9%), 14 (26.9%) pneumonias, 12 (23.1%) bones and joints infections, 10 (19.2%) SSTS, 6 (11.5%) occult bacteremia, 4 (7.7%) meningitis and 2 (3.8%) sepsis. Surgery was required in 18 cases (34.6%) and 17 patients (32.7%) needed intensive care. The medium hospital stay was 9.5 days (p25-75: 8-15 days). Three patients presented sequels and one patient died.

CONCLUSION

The ID due to SGA was a rare but serious reason for hospital admission. Skin and soft tissue infections, and pleuroneumonia were the most common forms of ID. The mortality of our sample was low despite the serious clinical manifestations.

When should clinicians suspect group A streptococcus empyema in children? A multicentre case-control study in French tertiary care centres

BACKGROUND

The incidence of invasive group A streptococcus (GAS) infections is increasing worldwide, whereas there has been a dramatic decrease in pneumococcal invasive diseases. Few data describing GAS pleural empyema in children are available.

OBJECTIVE

To describe the clinical and microbiological features, management and outcome of GAS pleural empyema in children and compare them with those of pneumococcal empyema.

DESIGN, SETTING AND PATIENTS

Fifty children admitted for GAS pleural empyema between January 2006 and May 2013 to 8 hospitals participating in a national pneumonia survey were included in a descriptive study and matched by age and centre with 50 children with pneumococcal empyema.

RESULTS

The median age of the children with GAS pleural empyema was 2 (range 0.1-7.6) years. Eighteen children (36%) had at least one risk factor for invasive GAS infection (corticosteroid use and/or current varicella). On admission, 37 patients (74%) had signs of circulatory failure, and 31 (62%) had a rash. GAS was isolated from 49/50 pleural fluid samples and from one blood culture. The commonest GAS genotype was emm1 (n=17/22). Two children died (4%). Children with GAS empyema presented more frequently with a rash (p<0.01), signs of circulatory failure (p=0.01) and respiratory disorders (p=0.02) and with low leucocyte levels (p=0.04) than children with pneumococcal empyema. Intensive care unit admissions (p<0.01), drainage procedures (p=0.04) and short-term complications (p=0.01) were also more frequent in patients with GAS empyema.

CONCLUSIONS

Pleural empyema following varicella or presenting with rash, signs of circulatory failure and leucopenia may be due to GAS. These features should prompt the addition to treatment of an antitoxin drug, such as clindamycin.

Invasive Group A Streptococcal Infections in Children: A Nationwide Survey in Finland

BACKGROUND

The incidence of invasive group A streptococcus (iGAS) infections varies in time and geographically for unknown reasons. We performed a nationwide survey to assess the population-based incidence rates and outcomes of children with iGAS infections.

METHODS

We collected data on patients from hospital discharge registries and the electronic databases of microbiological laboratories in Finland for the period 1996-2010. We then recorded the emm types or serotypes of the strains. The study physician visited all university clinics and collected the clinical data using the same data entry sheet.

RESULTS

We identified 151 children with iGAS infection. Varicella preceded iGAS infection in 20% of cases and fasciitis infection in 83% of cases. The annual incidence rate of iGAS infection was 0.93 per 100,000 in 1996-2000, 1.80 in 2001-2005 and 2.50 in 2006-2010. The proportion of emm 1.0 or T1M1 strains peaked in 1996-2000 and again in 2006-2010, to 44% and 37% of all typed isolates. The main clinical diagnoses of the patients were severe soft-tissue infection (46%), sepsis (28%), empyema (10%), osteoarticular infection (9%) and primary peritonitis (5%). Severe pain was the most typical symptom for soft-tissue infections. More than half of the patients underwent surgery and received clindamycin. The readmission rate was 7%, and the case fatality rate was 2%.

CONCLUSIONS

The incidence rate of pediatric iGAS infections tripled during our study. The increase was not, however, the result of a change in the strain types causing iGAS. Varicella immunization would likely have prevented a significant number of the cases.

Pediatric invasive streptococcal infection in northern and eastern regions of Hokkaido, Japan from 2010 to 2012

BACKGROUND

The frequency of occurrence of pediatric invasive streptococcal infection in Japan has not been studied, therefore the aim of this study was to survey the northern and eastern regions of Hokkaido from 2010 to 2012.

METHOD

Survey sheets were sent to the pediatric departments at 17 facilities where children in the subject region can be hospitalized. Responses were obtained from all of the 17 facilities.

RESULTS

Seven patients developed group A streptococcal infection over the 3 years, and their ages ranged from 1 day after the birth to 15 years old. Sepsis was diagnosed in five children, and empyema and arthritis in the knee were found in one child each, respectively. The number of cases in children under 15 years old was six excluding the child who was 15 years old, and the incidence rate per 100,000 population was 1.00. Eight children developed group B streptococcal infection, and their ages ranged from 0 days to 2 months after birth. Two cases were the early onset type (age within 7 days) and six cases were the late onset type. Five children developed sepsis and three children developed meningitis. The frequency of occurrence was 0.24 per 1000 births; which was 0.06 per 1000 births for the early onset type and was 0.18 per 1000 births for the late onset type. No reports for group C or group G hemolytic streptococcal infection were obtained.

CONCLUSIONS

The incidence rates identified in the present survey are similar to those in other advanced countries, and appear to be valid.

Susceptibility and emm type of Streptococcus pyogenes isolated from children with severe infection

Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of various antimicrobial agents were measured against 12 strains of Streptococcus pyogenes isolated from children with invasive infections between 2003 and 2012. The patients ranged in age from 1 day to 15 years, with patients younger than 5 years, including three neonates, accounting for a half of the patients. The disease was sepsis in four patients, skin and soft tissue infection in three patients, retropharyngeal abscess in two patients, pneumonia plus sepsis in one patient, empyema in one patient, and pyogenic arthritis in one patient. One patient with sepsis died, while cure without sequelae was achieved in all the remaining patients. When classified by type, emm1 (six strains) was the most prevalent type, followed by emm12 (two strains). The MIC₉₀/MBC₉₀ values were 0.015/0.015 μg/mL for penicillin G, 0.03/0.03 μg/mL for ampicillin, 0.015/0.03 μg/mL for cefotaxime, 0.03/0.03 μg/mL for ceftriaxone, 0.008/0.008 μg/mL for panipenem, 0.008/0.008 μg/mL for meropenem, and ≤0.004/≤0.004 μg/mL for doripenem, indicating the superior antimicrobial activities of carbapenem.

Current insights in invasive group A streptococcal infections in pediatrics

A rising incidence of invasive group A Streptococcus infections (IGASI) has been noted in children in the past three decades. The relative frequency of the infection types showed marked differences to IGASI in adults, and severity of the disease resulted in a mortality rate usually comprising between 3.6% and 8.3%. The emm1-type group A Streptococcus (GAS) subclone displaying a particular pattern of virulence factors was widely disseminated and prevalent in children with IGASI while the emm3-type GAS subclone appeared as a recent emerging genotype. However, the implication of these hypervirulent clones in the increase of IGASI in children is still controversial. Recent advances in our knowledge on pathogenesis of IGASI underlined that deregulation of virulence factor production, individual susceptibility, as well as exuberant cytokine response are important factors that may account for the severity of the disease in children. Future changes in IGASI epidemiology are awaited from current prospects for a safe and effective vaccine against GAS. IGASI are complex infections associating septic, toxic, and immunological disorders. Treatment has to be effective on both the etiologic agent and its toxins, due to the severity of the disease associated to the spread of highly virulent bacterial clones. More generally, emergence of virulent clones responsible for septic and toxic disease is a matter of concern in pediatric infectiology in the absence of vaccination strategy.

Assessment of cellular immune parameters in paediatric toxic shock syndrome: a report of five cases

Toxic shock syndrome (TSS) and septic shock (SS) share many clinical signs of an exacerbated inflammatory response. In this report, we investigated whether TSS presents similar features of delayed immunosuppression as described in SS. Five children with TSS from paediatric intensive care units in a university hospital were monitored. TSS cases were defined by the association of standardized clinical signs of TSS and confirmed by measurement of specific Vbeta expansions corresponding to toxin gene profile of the isolated strains. As in SS, an increased percentage of circulating regulatory T cells (Treg) was observed in patients with TSS. However, in contrast to SS, neither lymphopenia nor decreased HLA-DR expression on monocytes was measured. In conclusion, whereas SS and TSS exhibited similar clinical presentation, the present observation suggests that respective pathophysiological mechanisms induce different immune alterations. Future studies must isolate and better characterize the phenotypic and functional properties of Treg subsets during TSS to understand the mechanisms sustaining their increase, especially the putative role of superantigens.