The Group A Streptococcal Carrier State Reviewed: Still an Enigma

Amoxicillin vs. placebo to reduce symptoms in children with group A streptococcal pharyngitis: a randomized, multicenter, double-blind, non-inferiority trial

The efficacy of antibiotic therapy for group A streptococcus (GAS) pharyngitis is debated. The role of antibiotics in preventing complications seems limited, with the main potential benefit being symptom duration reduction. Our study aimed to evaluate whether a placebo is non-inferior to amoxicillin in reducing fever duration. We randomized 88 children between 3 and 15 years of age presenting with acute symptoms of pharyngitis and a positive rapid antigen detection test for GAS to receive 6-day treatment with either placebo (n = 46) or amoxicillin (n = 42). The primary outcome was the difference in fever duration, with a non-inferiority threshold set at 12 h. The secondary outcomes included pain intensity and complications of streptococcal pharyngitis. The mean difference in fever duration between the amoxicillin and placebo groups was 2.0 h (95% CI, - 8.3 to 12.3) in the per-protocol analysis and 2.8 h (95% CI, - 6.5 to 12.2) in the intention-to-treat analysis. Treatment failure was observed in six participants in the placebo group and two in the amoxicillin group (relative risk, 2.15; 95% CI, 0.44-10.57). All patients were identified early and recovered well. There was no clinically relevant difference in pain intensity between groups over the 7 days following randomization, with the largest difference of 0.5 (95% CI, - 0.62-1.80) observed on day 3.

CONCLUSION

Placebo appears to be non-inferior to amoxicillin in reducing fever duration. Pain intensity and risk of complications were similar between the two groups. These findings support the restrictive antibiotic treatment for streptococcal pharyngitis.

WHAT IS KNOWN

• Group A streptococcus pharyngitis is a common reason for prescribing antibiotics in pediatric care. • In high-income countries, while antibiotic treatment has not been effective in preventing non-suppurative complications, the primary justification for their use remains the reduction of symptoms.

WHAT IS NEW

• Our results suggest that antibiotics have a limited impact on the duration of fever and the intensity of pain in children with streptococcal pharyngitis. • Considering that suppurative complications can be promptly treated if they arise, we recommend a more judicious approach to antibiotic prescriptions.

TRIAL REGISTRATION

The trial is registered at the US National Institutes of Health (ClinicalTrials.gov) # NCT03264911 on 15.08.2017.

Impact of COVID-19 health precautions on asymptomatic Streptococcus pyogenes carriage in palestinian children: a pre- and post-pandemic study

BACKGROUND

Streptococcus pyogenes (Group A Streptococcus, GAS) is a significant pathogen that causes diverse infections, ranging from pharyngitis to severe invasive diseases. Asymptomatic carriage in children is pivotal for transmission. The COVID-19 pandemic's health measures, including mask wearing and enhanced hand hygiene, likely influenced GAS transmission dynamics. This study evaluated the impact of these precautions on the prevalence of asymptomatic pharyngeal GAS carriage among schoolchildren in the southern West Bank, Palestine.

METHODS

This cross-sectional study was conducted in two phases: pre-COVID-19 (November 2019-January 2020) and post-COVID-19 (November 2023-April 2024). Throat swabs were collected from 701 children (345 pre-COVID-19, 356 post-COVID-19) via cluster sampling. The samples were tested with the ABON Strep A rapid test and confirmed by culture. Sociodemographic, health, and household data were also collected. The statistical analyses included descriptive statistics, chi-square tests, and binary logistic regression.

RESULTS

The prevalence of asymptomatic pharyngeal GAS carriage declined from 15.7% pre-COVID-19 to 10.4% post-COVID-19 (p = 0.038). Significant reductions were observed among urban residents (23.5-10.1%, p = 0.003) and those from medium socioeconomic backgrounds (16.0-9.1%, p = 0.008). Compared with urban residents, rural residents had lower GAS carriage rates (adjusted OR = 0.505, p = 0.023). Carriage rates also decreased among children with frequent sore throats (17.6-7.3%, p = 0.007) and those using private wells (52.5-14.9%, p < 0.001). Higher BMI was a significant risk factor (adjusted OR = 17.68, p < 0.001), whereas frequent tooth brushing (adjusted OR = 0.055, p < 0.001) and hand washing (adjusted OR = 0.367, p < 0.001) were protective factors.

CONCLUSIONS

COVID-19-related health precautions were correlated with a significant reduction in asymptomatic GAS carriage among Palestinian children. These findings suggest that public health measures, such as mask wearing and hand hygiene, can influence the transmission of respiratory pathogens. Ongoing surveillance and targeted interventions are essential for managing GAS infections, particularly in resource-limited settings.

Group A Streptococcal Infections in Pediatric Age: Updates about a Re-Emerging Pathogen

Group A Streptococcus (GAS) presents a significant global health burden due to its diverse clinical manifestations ranging from mild infections to life-threatening invasive diseases. While historically stable, the incidence of GAS infections declined during the COVID-19 pandemic but resurged following the relaxation of preventive measures. Despite general responsiveness to β-lactam antibiotics, there remains an urgent need for a GAS vaccine due to its substantial global disease burden, particularly in low-resource settings. Vaccine development faces numerous challenges, including the extensive strain diversity, the lack of suitable animal models for testing, potential autoimmune complications, and the need for global distribution, while addressing socioeconomic disparities in vaccine access. Several vaccine candidates are in various stages of development, offering hope for effective prevention strategies in the future.

State transitions across the Strep A disease spectrum: scoping review and evidence gaps

The spectrum of diseases caused by Streptococcus pyogenes (Strep A) ranges from superficial to serious life-threatening invasive infections. We conducted a scoping review of published articles between 1980 and 2021 to synthesize evidence of state transitions across the Strep A disease spectrum. We identified 175 articles reporting 262 distinct observations of Strep A disease state transitions. Among the included articles, the transition from an invasive or toxin-mediated disease state to another disease state (i.e., to recurrent ARF, RHD or death) was described 115 times (43.9% of all included transition pairs) while the transition to and from locally invasive category was the lowest (n = 7; 0.02%). Transitions from well to any other state was most frequently reported (49%) whereas a relatively higher number of studies (n = 71) reported transition from invasive disease to death. Transitions from any disease state to locally invasive, Strep A pharyngitis to invasive disease, and chronic kidney disease to death were lacking. Transitions related to severe invasive diseases were more frequently reported than superficial ones. Most evidence originated from high-income countries and there is a critical need for new studies in low- and middle-income countries to infer the state transitions across the Strep A disease spectrum in these high-burden settings.

Group A β-hemolytic Streptococcal Pharyngitis: An Updated Review

BACKGROUND

Group A ß-hemolytic Streptococcus (GABHS) is the leading bacterial cause of acute pharyngitis in children and adolescents worldwide.

OBJECTIVE

This article aims to familiarize clinicians with the clinical manifestations, evaluation, diagnosis, and management of GABHS pharyngitis.

METHODS

A search was conducted in December 2022 in PubMed Clinical Queries using the key term "group A β-hemolytic streptococcal pharyngitis". This review covers mainly literature published in the previous ten years.

RESULTS

Children with GABHS pharyngitis typically present with an abrupt onset of fever, intense pain in the throat, pain on swallowing, an inflamed pharynx, enlarged and erythematous tonsils, a red and swollen uvula, enlarged tender anterior cervical lymph nodes. As clinical manifestations may not be specific, even experienced clinicians may have difficulties diagnosing GABHS pharyngitis solely based on epidemiologic or clinical grounds alone. Patients suspected of having GABHS pharyngitis should be confirmed by microbiologic testing (e.g., culture, rapid antigen detection test, molecular point-of-care test) of a throat swab specimen prior to the initiation of antimicrobial therapy. Microbiologic testing is generally unnecessary in patients with pharyngitis whose clinical and epidemiologic findings do not suggest GABHS. Clinical score systems such as the Centor score and McIssac score have been developed to help clinicians decide which patients should undergo diagnostic testing and reduce the unnecessary use of antimicrobials. Antimicrobial therapy should be initiated without delay once the diagnosis is confirmed. Oral penicillin V and amoxicillin remain the drugs of choice. For patients who have a non-anaphylactic allergy to penicillin, oral cephalosporin is an acceptable alternative. For patients with a history of immediate, anaphylactic-type hypersensitivity to penicillin, oral clindamycin, clarithromycin, and azithromycin are acceptable alternatives.

CONCLUSION

Early diagnosis and antimicrobial treatment are recommended to prevent suppurative complications (e.g., cervical lymphadenitis, peritonsillar abscess) and non-suppurative complications (particularly rheumatic fever) as well as to reduce the severity of symptoms, to shorten the duration of the illness and to reduce disease transmission.

Identifying genetic determinants of Streptococcus pyogenes-host interactions in a murine intact skin infection model

Streptococcus pyogenes is an obligate human pathobiont associated with many disease states. Here, we present a model of S. pyogenes infection using intact murine epithelium. We were able to perform RNA sequencing to evaluate genetic changes undertaken by both the bacterium and host at 5 and 24 h post-infection. Analysis of these genomic data demonstrate that S. pyogenes undergoes genetic adaptation to successfully infect the murine epithelium, including changes to metabolism and activation of the Rgg2/Rgg3 quorum-sensing (QS) system. Subsequent experiments demonstrate that an intact Rgg2/Rgg3 QS cascade is necessary to establish a stable superficial skin infection. QS cascade activation results in increased murine morbidity and bacterial burden on the skin. This phenotype is associated with gross changes to the murine skin and with evidence of inflammation. These experiments offer a method to investigate S. pyogenes-epithelial interactions and demonstrate that a well-studied QS pathway is critical to a persistent infection.

Streptococcus pyogenes carriage acquisition, persistence and transmission dynamics within households in The Gambia (SpyCATS): protocol for a longitudinal household cohort study

Background

Streptococcus pyogenes (StrepA) causes a significant burden of disease globally from superficial infections to invasive disease. It is responsible for over 500,000 deaths each year, predominantly in low- and middle-income countries (LMIC). Superficial StrepA infections of the skin and pharynx can lead to rheumatic heart disease, the largest cause of StrepA-related deaths in LMIC. StrepA can also asymptomatically colonise normal skin and the pharynx (carriage), potentially increasing infection risk. Streptococcus dysgalactiae subsp. equisimilis (SDSE) carriage is also common in LMIC and may interact with StrepA. This study aims to investigate StrepA and SDSE carriage and infection epidemiology, transmission dynamics and naturally acquired immunity within households in The Gambia.

Methods

A longitudinal household observational cohort study will be conducted over one year. 45 households will be recruited from the urban area of Sukuta, The Gambia, resulting in approximately 450 participants. Households will be visited monthly, and available participants will undergo oropharyngeal and normal skin swabbing. Incident cases of pharyngitis and pyoderma will be captured via active case reporting, with swabs taken from disease sites. Swabs will be cultured for the presence of group A, C and G beta-haemolytic streptococci. Isolates will undergo whole genome sequencing. At each visit, clinical, socio-demographic and social mixing data will be collected. Blood serum will be collected at baseline and final visit. Oral fluid and dried blood spot samples will be collected at each visit. Mucosal and serum anti-StrepA antibody responses will be measured.

Outcome

This study will report StrepA and SDSE clinical epidemiology, risk factors, transmission dynamics, and serological responses to carriage and infection. Detailed social mixing behaviour will be combined with phylogenetic relatedness to model the extent of transmission occurring withing and between households. The study will provide data to help meet global strategic StrepA research goals.

Tonsillitis and Sinusitis: A Narrative Review of Pathogenesis, Diagnosis, and Management

The review aims for a comprehensive examination of tonsillitis and sinusitis, covering their pathophysiology, diagnosis, and management, with a focus on recent breakthroughs and therapeutic practices. Tonsillitis, marked by inflammation of the tonsils, can result from viral or bacterial infections, particularly Streptococcus pyogenes, with attention to antibiotic resistance trends. This review discusses clinical manifestations, diagnostic criteria, and the importance of distinguishing viral from bacterial causes. Therapeutic interventions like antibiotics and tonsillectomy indications are evaluated within evolving guidelines. Regarding sinusitis, it explores its origins, contributing factors, and classification based on duration and pathophysiology. Viral infections, allergens, and structural anomalies' roles in pathogenesis are highlighted. Diagnostic modalities like imaging and endoscopic exams are assessed for their efficacy in guiding management decisions. The importance of precise diagnosis through clinical examination, microbiological testing, and imaging is emphasized for informed treatment choices. This review also delves into minimally invasive surgical procedures, particularly endoscopic sinus surgery and tonsillectomy, showcasing progress in these areas. In summary, it provides insights into tonsillitis and sinusitis, offering perspectives on their aetiology, diagnosis, and treatment while integrating current research and clinical standards to enhance patient care and healthcare resource utilization.

Role of serotype and virulence determinants of Streptococcus pyogenes biofilm bacteria in internalization and persistence in epithelial cells in vitro

Streptococcus pyogenes causes a multitude of local and systemic infections, the most common being pharyngitis in children. Recurrent pharyngeal infections are common and are thought to be due to the re-emergence of intracellular GAS upon completion of antibiotic treatment. The role of colonizing biofilm bacteria in this process is not fully clear. Here, live respiratory epithelial cells were inoculated with broth-grown or biofilm bacteria of different M-types, as well as with isogenic mutants lacking common virulence factors. All M-types tested adhered to and were internalized into epithelial cells. Interestingly, internalization and persistence of planktonic bacteria varied significantly between strains, whereas biofilm bacteria were internalized in similar and higher numbers, and all strains persisted beyond 44 hours, showing a more homogenous phenotype. The M3 protein, but not the M1 or M5 proteins, was required for optimal uptake and persistence of both planktonic and biofilm bacteria inside cells. Moreover, the high expression of capsule and SLO inhibited cellular uptake and capsule expression was required for intracellular survival. Streptolysin S was required for optimal uptake and persistence of M3 planktonic bacteria, whereas SpeB improved intracellular survival of biofilm bacteria. Microscopy of internalized bacteria showed that planktonic bacteria were internalized in lower numbers as individual or small clumps of bacteria in the cytoplasm, whereas GAS biofilm bacteria displayed a pattern of perinuclear localization of bacterial aggregates that affected actin structure. Using inhibitors targeting cellular uptake pathways, we confirmed that planktonic GAS mainly uses a clathrin-mediated uptake pathway that also required actin and dynamin. Clathrin was not involved in biofilm internalization, but internalization required actin rearrangement and PI3 kinase activity, possibly suggesting macropinocytosis. Together these results provide a better understanding of the potential mechanisms of uptake and survival of various phenotypes of GAS bacteria relevant for colonization and recurrent infection.

A pilot study to develop assessment tools for Group A Streptococcus surveillance studies

Introduction

Group A Streptococcus (GAS) causes pharyngitis (sore throat) and impetigo (skin sores) GAS pharyngitis triggers rheumatic fever (RF) with epidemiological evidence supporting that GAS impetigo may also trigger RF in Australian Aboriginal children. Understanding the concurrent burden of these superficial GAS infections is critical to RF prevention. This pilot study aimed to trial tools for concurrent surveillance of sore throats and skins sore for contemporary studies of RF pathogenesis including development of a sore throat checklist for Aboriginal families and pharynx photography.

Methods

Yarning circle conversations and semi-structured interviews were performed with Aboriginal caregivers and used to develop the language and composition of a sore throat checklist. The sore throat story checklist was combined with established methods of GAS pharyngitis and impetigo surveillance (examination, bacteriological culture, rapid antigen detection and serological tests) and new technologies (photography) and used for a pilot cross-sectional surveillance study of Aboriginal children attending their health clinic for a routine appointment. Feasibility, acceptability, and study costs were compiled.

Results

Ten Aboriginal caregivers participated in the sore-throat yarning circles; a checklist was derived from predominant symptoms and their common descriptors. Over two days, 21 Aboriginal children were approached for the pilot surveillance study, of whom 17 were recruited; median age was 9 years [IQR 5.5-13.5], 65% were female. One child declined throat swabbing and three declined finger pricks; all other surveillance elements were completed by each child indicating high acceptability of surveillance assessments. Mean time for screening assessment was 19 minutes per child. Transport of clinical specimens enabled gold standard microbiological and serological testing for GAS. Retrospective examination of sore throat photography concorded with assessments performed on the day.

Conclusion

Yarning circle conversations were effective in deriving culturally appropriate sore throat questionnaires for GAS pharyngitis surveillance. New and established tools were feasible, practical and acceptable to participants and enable surveillance to determine the burden of superficial GAS infections in communities at high risk of RF. Surveillance of GAS pharyngitis and impetgio in remote Australia informs primary RF prevention with potential global translation.

Streptococcus pyogenes carriage acquisition, persistence and transmission dynamics within households in The Gambia (SpyCATS): protocol for a longitudinal household cohort study

Background Streptococcus pyogenes (StrepA) causes a significant burden of disease globally from superficial infections to invasive disease. It is responsible for over 500,000 deaths each year, predominantly in low- and middle-income countries (LMIC). Superficial StrepA infections of the skin and pharynx can lead to rheumatic heart disease, the largest cause of StrepA-related deaths in LMIC. StrepA can also asymptomatically colonise normal skin and the pharynx (carriage), potentially increasing infection risk. Streptococcus dysgalactiae subsp. equisimilis (SDSE) carriage is also common in LMIC and may interact with StrepA. This study aims to investigate StrepA and SDSE carriage and infection epidemiology, transmission dynamics and naturally acquired immunity within households in The Gambia. Methods A longitudinal household observational cohort study will be conducted over one year. 45 households will be recruited from the urban area of Sukuta, The Gambia, resulting in approximately 450 participants. Households will be visited monthly, and available participants will undergo oropharyngeal and normal skin swabbing. Incident cases of pharyngitis and pyoderma will be captured via active case reporting, with swabs taken from disease sites. Swabs will be cultured for the presence of group A, C and G beta-haemolytic streptococci. Isolates will undergo whole genome sequencing. At each visit, clinical, socio-demographic and social mixing data will be collected. Blood serum will be collected at baseline and final visit. Oral fluid and dried blood spot samples will be collected at each visit. Mucosal and serum anti-StrepA antibody responses will be measured. Outcome This study will report StrepA and SDSE clinical epidemiology, risk factors, transmission dynamics, and serological responses to carriage and infection. Detailed social mixing behaviour will be combined with phylogenetic relatedness to model the extent of transmission occurring withing and between households. The study will provide data to help meet global strategic StrepA research goals.

Use of Host Response to Refine the Diagnosis of Group A Streptococcal Pharyngitis

BACKGROUND

Current diagnostic tests for pharyngitis do not distinguish between symptomatic group A Streptococcus (GAS) infection and asymptomatic colonization, resulting in over-diagnosis and unnecessary use of antibiotics. We assessed whether measures of host response could make this distinction.

METHODS

We enrolled 18 children with pharyngitis having Centor scores of 4 or 5 and 21 controls without pharyngitis or other acute infections. Both groups had throat cultures, molecular tests for GAS and respiratory viruses and IgM serology for Epstein-Barr virus. Host response was evaluated with white blood cell count (WBC), C-reactive protein (CRP), procalcitonin (PCT), and sequencing of RNA from peripheral blood leukocytes.

RESULTS

Of 18 cases, 11 had GAS pharyngitis, 3 had adenovirus pharyngitis and 4 had other pharyngitis. Among asymptomatic controls, 5 were positive for GAS. WBC, CRP, and PCT were higher in subjects with pharyngitis compared to asymptomatic controls including those with GAS. Transcriptional profiles from children with symptomatic GAS were clearly distinct from those of children in all other groups. The levels of two genes, CD177 and TLR5 each individually accurately distinguished between symptomatic and asymptomatic GAS. Optimal diagnostic sensitivity and specificity were achieved by the combination of CRP and PCT, and by each of the two gene markers.

CONCLUSION

In this exploratory study, we showed that traditional measures of inflammation and markers of host gene expression distinguish between symptomatic and asymptomatic GAS. These results point to future rapid molecular approaches for improving the diagnosis of GAS pharyngitis, that may help reduce unnecessary antibiotic use.

High Diversity of emm Types and Marked Tetracycline Resistance of Group A Streptococci and Other ß-Hemolytic Streptococci in Gabon, Central Africa

BACKGROUND

Group A ß-hemolytic streptococcus (GABHS) is a leading pathogen worldwide and post-streptococcal sequelae is a major cause of morbidity and mortality in resource-limited countries. The M protein (coded by the emm gene) is a key virulence factor and a component of GABHS vaccine candidates. As data on BHS in Central Africa are scarce, antibiotic resistance, emm diversity and potential vaccine coverage were investigated.

METHODS

In a prospective cross-sectional study, 1014 Gabonese were screened for streptococcal throat carriage, tonsillopharyngitis and pyoderma by throat and skin smear tests. All BHS were isolated, species were identified and analysis of antibiotic resistance, emm types and emm clusters was performed.

RESULTS

One hundred sixty-five BHS were detected, comprising 76 GABHS, 36 group C ß-hemolytic streptococcus (GCBHS) and 53 group G ß-hemolytic streptococcus (GGBHS) in 140 carrier, 9 tonsillopharyngitis and 16 pyoderma isolates. Eighty percentage of GABHS, 78% of GCBHS and 79% of GGBHS were tetracycline resistant. Forty-six emm types were identified. GABHS emm58, emm65 and emm81 were most prevalent (26%). Emm diversity of GABHS was the highest, GCBHS and GGBHS were less divers. Every second GABHS, every third GCBHS and every tenth GGBHS carrier was colonized with emm types detected in tonsillopharyngitis or pyoderma isolates.

CONCLUSIONS

Tetracycline resistance and emm type diversity was high among BHS carriers in Gabon with a potential coverage of 58% by the 30-valent GABHS vaccine. A relevant overlap of carrier emm types with emm types found in tonsillopharyngitis and pyoderma characterizes a shared pool of circulating BHS strains.

Frequency of transmission, asymptomatic shedding, and airborne spread of Streptococcus pyogenes in schoolchildren exposed to scarlet fever: a prospective, longitudinal, multicohort, molecular epidemiological, contact-tracing study in England, UK

BACKGROUND

Despite recommendations regarding prompt treatment of cases and enhanced hygiene measures, scarlet fever outbreaks increased in England between 2014 and 2018. We aimed to assess the effects of standard interventions on transmission of Streptococcus pyogenes to classroom contacts, households, and classroom environments to inform future guidance.

METHODS

We did a prospective, longitudinal, multicohort, molecular epidemiological, contact-tracing study in six settings across five schools in Greater London, UK. Schools and nurseries were eligible to participate if they had reported two cases of scarlet fever within 10 days of each other among children aged 2-8 years from the same class, with the most recent case arising in the preceding 48 h. We cultured throat swabs from children with scarlet fever, classroom contacts, and household contacts at four timepoints. We also cultured hand swabs and cough plates from all cases in years 1 and 2 of the study, and from classroom contacts in year 2. Surface swabs from toys and other fomites in classrooms were cultured in year 1, and settle plates from classrooms were collected in year 2. Any sample with S pyogenes detected was recorded as positive and underwent emm genotyping and genome sequencing to compare with the outbreak strain.

FINDINGS

Six classes, comprising 12 cases of scarlet fever, 17 household contacts, and 278 classroom contacts were recruited between March 1 and May 31, 2018 (year 1), and between March 1 and May 31, 2019 (year 2). Asymptomatic throat carriage of the outbreak strains increased from 11 (10%) of 115 swabbed children in week 1, to 34 (27%) of 126 in week 2, to 26 (24%) of 108 in week 3, and then five (14%) of 35 in week 4. Compared with carriage of outbreak S pyogenes strains, colonisation with non-outbreak and non-genotyped S pyogenes strains occurred in two (2%) of 115 swabbed children in week 1, five (4%) of 126 in week 2, six (6%) of 108 in week 3, and in none of the 35 children in week 4 (median carriage for entire study 2·8% [IQR 0·0-6·6]). Genome sequencing showed clonality of outbreak isolates within each of six classes, confirming that recent transmission accounted for high carriage. When transmissibility was tested, one (9%) of 11 asymptomatic carriers of emm4 and five (36%) of 14 asymptomatic carriers of emm3.93 had a positive cough plate. The outbreak strain was identified in only one (2%) of 60 surface swabs taken from three classrooms; however, in the two classrooms with settle plates placed in elevated locations, two (17%) of 12 and six (50%) of 12 settle plates yielded the outbreak strain.

INTERPRETATION

Transmission of S pyogenes in schools is intense and might occur before or despite reported treatment of cases, underlining a need for rapid case management. Despite guideline adherence, heavy shedding of S pyogenes by few classroom contacts might perpetuate outbreaks, and airborne transmission has a plausible role in its spread. These findings highlight the need for research to improve understanding and to assess effectiveness of interventions to reduce airborne transmission of S pyogenes.

FUNDING

Action Medical Research, UK Research Innovation, and National Institute for Health Research.

Global spatial dynamics and vaccine-induced fitness changes of Bordetella pertussis

As with other pathogens, competitive interactions between Bordetella pertussis strains drive infection risk. Vaccines are thought to perturb strain diversity through shifts in immune pressures; however, this has rarely been measured because of inadequate data and analytical tools. We used 3344 sequences from 23 countries to show that, on average, there are 28.1 transmission chains circulating within a subnational region, with the number of chains strongly associated with host population size. It took 5 to 10 years for B. pertussis to be homogeneously distributed throughout Europe, with the same time frame required for the United States. Increased fitness of pertactin-deficient strains after implementation of acellular vaccines, but reduced fitness otherwise, can explain long-term genotype dynamics. These findings highlight the role of vaccine policy in shifting local diversity of a pathogen that is responsible for 160,000 deaths annually.

Streptococcal Pharyngitis: Compliance With National Testing Guidelines in a Pediatric Emergency Department

OBJECTIVES

The Infectious Diseases Society of America (IDSA) guidelines regarding group A streptococcal (GAS) pharyngitis advise against routine testing for patients younger than 3 years, patients without pharyngitis, and patients with symptoms suggesting a viral infection. Group A streptococcal testing may be overused in some clinical settings; thus, we conducted this study to evaluate compliance with the IDSA guidelines in a pediatric emergency department (ED) setting.

METHODS

This retrospective cohort study describes patients younger than 18 years presenting to 2 urban pediatric EDs in 2016 who underwent rapid antigen detection testing for GAS pharyngitis. Testing was classified as noncompliant with the IDSA guidelines if the chief complaint was not indicative of GAS infection and/or the patient age was younger than 3 years. Appropriate nonparametric tests compared groups by IDSA testing compliance status.

RESULTS

A total of 13,585 patient encounters met inclusion criteria; 5255 (39%) were noncompliant with the IDSA testing guidelines, the majority due to a chief complaint inconsistent with GAS pharyngitis (67%) and secondarily due to the age of younger than 3 years (48%). Among the patients with noncompliant testing, 51% were prescribed an antibiotic, and return encounters were more likely to occur (13% vs 10%, P < 0.001). Return encounters more commonly resulted in respiratory diagnoses in those with noncompliant GAS testing (60% vs 45%, P < 0.001).

CONCLUSIONS

Nearly 40% of all pediatric ED encounters with GAS testing were noncompliant with the IDSA guidelines and were associated with greater return encounter rates. Potential negative outcomes from noncompliant GAS testing include misdiagnosis, inappropriate use of antibiotics, allergic reactions, and loss of school days. Informed interventions to reduce unnecessary GAS testing are warranted.

Distribution, Diversity and Roles of CRISPR-Cas Systems in Human and Animal Pathogenic Streptococci

Streptococci form a wide group of bacteria and are involved in both human and animal pathologies. Among pathogenic isolates, differences have been highlighted especially concerning their adaptation and virulence profiles. CRISPR-Cas systems have been identified in bacteria and many streptococci harbor one or more systems, particularly subtypes I-C, II-A, and III-A. Since the demonstration that CRISPR-Cas act as an adaptive immune system in Streptococcus thermophilus, a lactic bacteria, the diversity and role of CRISPR-Cas were extended to many germs and functions were enlarged. Among those, the genome editing tool based on the properties of Cas endonucleases is used worldwide, and the recent attribution of the Nobel Prize illustrates the importance of this tool in the scientific world. Another application is CRISPR loci analysis, which allows to easily characterize isolates in order to understand the interactions of bacteria with their environment and visualize species evolution. In this review, we focused on the distribution, diversity and roles of CRISPR-Cas systems in the main pathogenic streptococci.

COVID-19 and Acute Otitis Media in Children: A Case Series

Background:

The association of SARS-CoV-2 with acute otitis media (AOM) in children is poorly understood.

Methods:

Cases were identified as a subpopulation within the NO TEARS prospective AOM study in Denver, CO from March to December 2020. Children enrolled were 6 to 35 months of age with uncomplicated AOM; those with AOM and SARS-CoV-2 were included. Data was obtained from electronic medical records and research case report forms.

Results:

A total of 108 patients enrolled in the NO TEARS study from May 2019 through December 2020 (all subsequently tested for SARS CoV-2). During the COVID-19 pandemic study period (March-December 2020), 16 patients enrolled, and 7 (43.6%) were identified with AOM/COVID-19 co-infection. Fever was present in 3 of 7 children (29%). Four children (57%) attended daycare. Only 2 children (29%) had SARS CoV-2 testing as part of their clinical workup. Mean AOM-SOS^© scores were similar among SARS CoV-2 positive and negative patients with no statistical significance with two-sided t-tests: 13.6 (±4.5) versus 14.2 (±4.9) at enrollment, 1.4 (±1.8) versus 4.2 (±4.9) on Day 5, and 0.6 (±0.9) versus 2.5 (±6.1) on Day 14. Among the 7 cases, no child had an AOM treatment failure or recurrence within 3 to 14 or 15 to 30 days respectively. Of the 6 patients with completed bacterial and viral testing, a bacterial pathogen was identified in all 6, and a viral pathogen in 3 (50%).

Conclusions:

COVID-19 and AOM can co-exist. Providers should maintain a high index of suspicion for COVID-19 even in patients with clinical AOM and should not use a diagnosis of AOM to exclude COVID-19.

Pattern and appropriateness of antibiotic prescriptions for upper respiratory tract infections in primary care paediatric patients

OBJECTIVES

The aim of this cross-sectional study was to investigate the pattern of antibiotic prescriptions for upper respiratory tract infections (URTIs) in children seen by primary care paediatricians (PCPs).

METHODS

Data were collected from face-to-face interviews administered to a sample of parents of outpatient children aged 0-14 years in two regions in Southern Italy. To be eligible, children had to be diagnosed with sinusitis, pharyngotonsillitis, otitis media, bronchitis, influenza or a common cold. The presence of an indication of antibiotic therapy was evaluated according to national and international guidelines.

RESULTS

An antibiotic prescription was indicated in 57 (10.1%) of the sampled patients, of whom 33.3% did not receive an antibiotic prescription; among the 508 patients for whom an antibiotic prescription was not indicated, 27.4% received a prescription. Of all PCP consultations, 72% were appropriate (an antibiotic was prescribed when indicated and not prescribed when not indicated), whilst an antibiotic prescription not indicated by guidelines was given to 24.6% of the participants, and 3.4% of the sample did not receive an antibiotic prescription when indicated. The most frequently prescribed antibiotic was amoxicillin with clavulanic acid. A rapid microbiological examination was performed in two patients.

CONCLUSIONS

The study findings highlight a high rate of sub-optimal antibiotic therapeutic profile. Over-prescription of antibiotic therapy and the use of broad-spectrum molecules are widespread in children with URTIs. Antibiotic under-prescription, which may deprive paediatric patients of an effective treatment when indicated, also occurs.

Comparison of group A streptococcal titres in healthy children and those with pharyngitis and skin infections

OBJECTIVES

Rates of acute rheumatic fever, a sequelae of group A Streptococcal (GAS) infection, remain unacceptably high in Indigenous Māori and Pacific children in New Zealand. This prospective study aimed to describe GAS antibody titres in healthy children (5-14 years) by ethnicity, and to determine how paired titres vary with GAS culture positive and negative pharyngitis, and GAS skin infections.

METHODS

Analysis included 887 children (32% Māori, 36% Pacific, 33% European/Other) from Auckland, New Zealand. Cases comprise 772 children who had a sore throat or skin infection, which resulted in a swab taken for culture. Healthy controls were asymptomatic (N = 154) and matched by age, ethnicity and region. All participants had a serum sample, with a second sample collected from cases only. Sera were analysed for anti-streptolysin O (ASO) and anti-DNase-B (ADB) antibodies.

RESULTS

Healthy Māori and Pacific children had higher GAS antibody titres than healthy European/Other children. Children with GAS-positive sore throat had the highest mean ASO titres and children with GAS-positive skin infection had the highest mean ADB titres. When a two-fold increase or an upper limit of normal cut-off (ASO 450 IU/ml, ADB 400 U/ml) was applied to titres from children with GAS-positive sore throat, 62.1% were classified as having serologically confirmed GAS pharyngitis and 37.9% had GAS detected without serological response.

CONCLUSIONS

Elevated ASO titres were associated with GAS pharyngitis and elevated ADB titres were associated with GAS skin infections in New Zealand children. Higher ASO/ADB titres in healthy Māori and Pacific children could indicate a greater prior exposure to GAS infections.

Incidence of Pharyngitis, Sinusitis, Acute Otitis Media, and Outpatient Antibiotic Prescribing Preventable by Vaccination Against Group A Streptococcus in the United States

BACKGROUND

Group A Streptococcus (GAS) is a leading cause of acute respiratory conditions that frequently result in antibiotic prescribing. Vaccines against GAS are currently in development.

METHODS

We estimated the incidence rates of healthcare visits and antibiotic prescribing for pharyngitis, sinusitis, and acute otitis media (AOM) in the United States using nationally representative surveys of outpatient care provision, supplemented by insurance claims data. We estimated the proportion of these episodes attributable to GAS and to GAS emm types included in a proposed 30-valent vaccine. We used these outputs to estimate the incidence rates of outpatient visits and antibiotic prescribing preventable by GAS vaccines with various efficacy profiles under infant and school-age dosing schedules.

RESULTS

GAS pharyngitis causes 19.1 (95% confidence interval [CI], 17.3-21.1) outpatient visits and 10.2 (95% CI, 9.0-11.5) antibiotic prescriptions per 1000 US persons aged 0-64 years, annually. GAS pharyngitis causes 93.2 (95% CI, 82.3-105.3) visits and 53.2 (95% CI, 45.2-62.5) antibiotic prescriptions per 1000 children ages 3-9 years, annually, representing 5.9% (95% CI, 5.1-7.0%) of all outpatient antibiotic prescribing in this age group. Collectively, GAS-attributable pharyngitis, sinusitis, and AOM cause 26.9 (95% CI, 23.9-30.8) outpatient visits and 16.1 (95% CI, 14.0-18.7) antibiotic prescriptions per 1000 population, annually. A 30-valent GAS vaccine meeting the World Health Organization's 80% efficacy target could prevent 5.4% (95% CI, 4.6-6.4%) of outpatient antibiotic prescriptions among children aged 3-9 years. If vaccine prevention of GAS pharyngitis made the routine antibiotic treatment of pharyngitis unnecessary, up to 17.1% (95% CI, 15.0-19.6%) of outpatient antibiotic prescriptions among children aged 3-9 years could be prevented.

CONCLUSIONS

An efficacious GAS vaccine could prevent substantial incidences of pharyngitis infections and associated antibiotic prescribing in the United States.

The treatment of streptococcal tonsillitis/pharyngitis in young children

Pharyngitis is common in children, accounting for nearly 12 million visits annually in the United States. Streptococcus pyogenes or group A streptococcus (GAS) is the most common bacterial cause of pharyngitis for which antibiotics are indicated. Antibiotic treatment of streptococcal pharyngitis virtually eliminates the presence of bacteria from the pharynx and thus removes the risk of subsequent rheumatic fever. GAS is spread from person to person via respiratory droplets with a short incubation period of 2∼5 days. GAS pharyngitis peaks in the late winter and early spring months when children are predominately indoors for school and sports. Colonization is also higher in winter months, and while up to 20% of school age children are colonized with GAS in their throat during this time, colonization has not been shown to contribute to the spread of disease. In low- and middle-income countries and other situations in which crowding is common (e.g., schools), outbreaks of pharyngitis are common. GAS pharyngitis can occur at all ages and it is most common in school-aged children with a peak at 7∼8 years of age. Pharyngitis caused by GAS is rare in children <3 years of age and becomes much less common in late adolescence through adulthood.

Impact of Streptococcus pyogenes infection in susceptibility to psoriasis: A systematic review and meta-analysis

BACKGROUND

Psoriasis is one of the most common chronic systemic diseases, mainly appearing as lesions on the skin and joints, and is associated with a high mortality due to a lack of standard treatment. The exact mechanism of this disease is not fully understood, but the inflammatory response and dysregulation of the immune system are the most important molecular processes that trigger this disease. The skin microflora is one of the main factors involved in inducing, maturing, and dysregulating the immune system, which may underly the development of psoriasis.

AIM

To determine the impact of Streptococcus pyogenes (S. pyogenes) infection and susceptibility to psoriasis using available case-control studies.

METHODS

In this study, we conducted a comprehensive literature search using PubMed, Scopus, Web of science, and Google scholar databases to obtain all available relevant studies on the association between S. pyogenes and psoriasis. We pooled the data using Comprehensive Meta-analysis software to investigate the role of S. pyogenes infection in the development of psoriasis. The probable connection between S. pyogenes and susceptibility to psoriasis was assessed using the odds ratio (OR) with corresponding 95% confidence intervals (CIs).

RESULTS

Data from 781 cases were evaluated in this study. Our results showed that the rate of infection with S. pyogenes in psoriatic patients and healthy individuals was 33.4% (95%CI: 27.8-39.6) and 16.2% (95%CI: 9.7-25.9), respectively. S. pyogenes infection significantly increased the risk of psoriasis (OR: 6.58; 95%CI: 3.64-11.87; P = 0.001).

CONCLUSION

S. pyogenes infection can significantly increase the risk of psoriasis. Thus, infection with S. pyogenes is a risk factor for the initiation and development of psoriatic events.

Structured review of primary interventions to reduce group A streptococcal infections, acute rheumatic fever and rheumatic heart disease

Rheumatic heart disease (RHD) is a large, preventable, global public health burden. In New Zealand (NZ), acute rheumatic fever (ARF) and RHD rates are highest for Māori and Pacific children. This structured review explores the evidence for primary prevention interventions to diagnose and effectively treat group A Streptococcus (GAS) pharyngitis and skin infections to reduce rates of ARF and RHD. Medline, EMBASE and Scopus databases were searched as well as other electronic publications. Included were 50 publications from 1980 onwards. This review has identified that there is little available evidence for effective primary prevention strategies to reduce ARF rates in NZ. However, two primary intervention strategies that should be considered by communities at high-risk of ARF are: the use of school-based clinics to identify and treat GAS pharyngitis and GAS skin infections; and intramuscular benzathine penicillin G with lignocaine analgesia in children who present with a GAS positive throat.

Modes of transmission and attack rates of group A Streptococcal infection: a protocol for a systematic review and meta-analysis

BACKGROUND

Group A Streptococcus (Strep A) is an important cause of mortality and morbidity globally. This bacterium is responsible for a range of different infections and post-infectious sequelae. Summarising the current knowledge of Strep A transmission to humans will address gaps in the evidence and inform prevention and control strategies. The objective of this study is to evaluate the modes of transmission and attack rates of group A streptococcal infection in human populations.

METHODS

This systematic review protocol was prepared according to the Preferred Reporting Items for Systematic reviews and Meta-analysis Protocols (PRISMA-P) 2015 Statement. Using a comprehensive search strategy to identify any transmission studies that have been published in English since 1980, full-text articles will be identified and considered for inclusion against predefined criteria. We will include all studies reporting on Strep A transmission, who have identified a mode of transmission, and who reported attack rates. Risk of bias will be appraised using an appropriate tool. Our results will be described narratively and where feasible and appropriate, a meta-analysis utilizing the random-effects model will be used to aggregate the incidence proportions (attack rates) for each mode of transmission. In addition, we will also evaluate the emm genotype variants of the M protein causing Strep A infection and the association with transmission routes and attack rates, if any, by setting, socioeconomic background and geographical regions.

DISCUSSION

We anticipate that this review will contribute to elucidating Strep A modes of transmission which in turn, will serve to inform evidence-based strategies including environmental health activities to reduce the transmission of Strep A in populations at risk of severe disease.

TRIAL REGISTRATION

Systematic review registration: PROSPERO ( CRD42019138472 ).

Paediatrics: how to manage pharyngitis in an era of increasing antimicrobial resistance

The goal of this narrative review of pharyngitis is to summarize the practical aspects of the management of sore throat in children in high- and middle-income countries. A traditional review of the literature was performed. Most cases of pharyngitis are viral and self-limited, although rarely viral pharyngitis due to Epstein–Barr leads to airway obstruction. Bacterial pharyngitis is usually due to group A streptococcus (GAS), occurs primarily in children aged 5–15 years, and presents as sore throat in the absence of rhinitis, laryngitis or cough. Again, most cases are self-limited; antibiotics hasten recovery by only 1–2 days. Guidelines vary by country, but antibiotics are commonly recommended for proven GAS pharyngitis as they may prevent rare but severe complications, in particular rheumatic fever (RF). In this era of antimicrobial stewardship, it should be extremely rare that antibiotics are prescribed for presumed GAS pharyngitis until GAS has been detected. Even with proven GAS pharyngitis, it is controversial whether children at low risk for RF should routinely be prescribed antibiotics as the number needed to treat to prevent one case of RF is undoubtedly very large. When treatment is offered, the antibiotics of choice are penicillin or amoxicillin as they are narrow spectrum and resistance resulting in clinical failure is yet to be documented. A 10-day oral course is recommended as shorter courses appear to be less likely to clear carriage of GAS. However, the evidence that one needs to clear carriage to prevent RF is low quality and indirect.

A Review of Streptococcus pyogenes: Public Health Risk Factors, Prevention and Control

Streptococcus pyogenes, (colloquially named "group A streptococcus" (GAS)), is a pathogen of public health significance, infecting 18.1 million people worldwide and resulting in 500,000 deaths each year. This review identified published articles on the risk factors and public health prevention and control strategies for mitigating GAS diseases. The pathogen causing GAS diseases is commonly transmitted via respiratory droplets, touching skin sores caused by GAS or through contact with contaminated material or equipment. Foodborne transmission is also possible, although there is need for further research to quantify this route of infection. It was found that GAS diseases are highly prevalent in developing countries, and among indigenous populations and low socioeconomic areas in developed countries. Children, the immunocompromised and the elderly are at the greatest risk of S. pyogenes infections and the associated sequelae, with transmission rates being higher in schools, kindergartens, hospitals and residential care homes. This was attributed to overcrowding and the higher level of social contact in these settings. Prevention and control measures should target the improvement of living conditions, and personal and hand hygiene. Adherence to infection prevention and control practices should be emphasized in high-risk settings. Resource distribution by governments, especially in developed countries, should also be considered.

Association of Group A Streptococcus Exposure and Exacerbations of Chronic Tic Disorders: A Multinational Prospective Cohort Study

OBJECTIVE

To examine prospectively the association between group A Streptococcus (GAS) pharyngeal exposures and exacerbations of tics in a large multicenter population of youth with chronic tic disorders (CTD) across Europe.

METHODS

We followed up 715 children with CTD (age 10.7 ± 2.8 years, 76.8% boys), recruited by 16 specialist clinics from 9 countries, and followed up for 16 months on average. Tic, obsessive-compulsive symptom (OCS), and attention-deficit/hyperactivity disorder (ADHD) severity was assessed during 4-monthly study visits and telephone interviews. GAS exposures were analyzed using 4 possible combinations of measures based on pharyngeal swab and serologic testing. The associations between GAS exposures and tic exacerbations or changes of tic, OC, and ADHD symptom severity were measured, respectively, using multivariate logistic regression plus multiple failure time analyses and mixed effects linear regression.

RESULTS

A total of 405 exacerbations occurred in 308 of 715 (43%) participants. The proportion of exacerbations temporally associated with GAS exposure ranged from 5.5% to 12.9%, depending on GAS exposure definition. We did not detect any significant association of any of the 4 GAS exposure definitions with tic exacerbations (odds ratios ranging between 1.006 and 1.235, all p values >0.3). GAS exposures were associated with longitudinal changes of hyperactivity-impulsivity symptom severity ranging from 17% to 21%, depending on GAS exposure definition.

CONCLUSIONS

This study does not support GAS exposures as contributing factors for tic exacerbations in children with CTD. Specific workup or active management of GAS infections is unlikely to help modify the course of tics in CTD and is therefore not recommended.

Streptococcal Throat Carriage among Primary School Children Living in Uyo, Southern Nigeria

Surveillance of the carrier state for β-hemolytic streptococcal (BHS) throat infections remains essential for disease control. Recent published works from Sub-Saharan Africa have suggested a changing epidemiology in the burden of BHS throat infections. The objective of the present study was therefore to determine the prevalence and pattern of BHS throat carriage in school-aged children in Uyo, Akwa Ibom State. This was a prospective cross-sectional study of 276 primary school children in Uyo. Subjects were recruited by multistage random sampling. Obtained throat swabs were cultured on 5% sheep blood agar. Lancefield grouping on positive cultures was done by using the Oxoid Streptococcal Grouping Latex Agglutination Kit, United Kingdom. Antimicrobial susceptibility testing was done with the disk diffusion method. Associations were tested with Fischer's exact test. The prevalence of BHS carriage was 3.3%. Group C Streptococcus was identified in 89% of isolates and Group G Streptococcus in 11%. Younger age and larger household size were associated with asymptomatic streptococcal throat infections. Antimicrobial susceptibility was highest with cefuroxime and clindamycin (89% of isolates each), while 78% of isolates were susceptible to penicillin. None of the tested isolates was susceptible to co-trimoxazole. The prevalence of streptococcal throat carriage in the study area was low. There were no Group A Streptococcus isolates suggesting an evolving epidemiology of BHS disease in the study area.

Prevalence and predicting factors of Group A beta-hemolytic Streptococcus carrier state in primary schoolchildren

Introduction:

Aim and Objectives:

Material and Methods:

Results:

Conclusion:

Perianal streptococcal disease in childhood: systematic literature review

Group A Streptococcus has been associated with a perianal infection. We conducted a systematic review of the literature on childhood streptococcal perianitis in three databases: Excerpta Medica, National Library of Medicine, and Web of Science. The main purposes were to document the clinical features, the tendency to recur, the association with an asymptomatic streptococcal throat carriage, the accuracy of rapid streptococcal tests, and the mechanism possibly underlying the acquisition of this infection. More than 80% of cases are boys ≤7.0 years of age with defecation disorders, perianal pain, local itch, rectal bleeding, or fissure and a sharply demarcated perianal redness. Perianitis is associated with a streptococcal tonsillopharyngitis in about every fifth case. The time to diagnosis is ≥3 weeks in 65% of cases. Recurrences occur within 3½ months in about 20% of cases. An asymptomatic group A streptococcal throat carriage occurs in 63% of cases. As compared with perianal Streptococcus A culture, the rapid streptococcal tests have a positive predictive value of 80% and a negative predictive value of 96%. It is hypothesized that digital inoculation from nasopharynx to anus underlies perianitis. Many cases are likely caused directly by children, who are throat and nasal carriers of Streptococcus A. Some cases might occur in children, who have their bottoms wiped by caregivers with streptococcal tonsillopharyngitis or carriage of Streptococcus.Conclusion: Perianitis is an infection with a distinctive presentation and a rather long time to diagnosis. There is a need for a wider awareness of this condition among healthcare professionals. What is Known: • Group A Streptococcus may cause perianitis in childhood. • Systemic antimicrobials (penicillin V, amoxycillin, or cefuroxime) are superior to topical treatment. What is New: • The clinical presentation is distinctive (defecation disorders, perianal pain, local itch, rectal bleeding, or fissure and a sharply demarcated perianal redness). • The time to diagnosis is usually ≥3 weeks. Recurrences occur in about 20% of cases.

Rheumatic heart disease: A review of the current status of global research activity

Rheumatic heart disease (RHD) is a serious and long-term consequence of acute rheumatic fever (ARF), an autoimmune sequela of a mucosal infection by Streptococcus pyogenes (Group A Streptococcus, Strep A). The pathogenesis of ARF and RHD is complex and not fully understood but involves host and bacterial factors, molecular mimicry, and aberrant host innate and adaptive immune responses that result in loss of self-tolerance and subsequent cross-reactivity with host tissues. RHD is entirely preventable yet claims an estimated 320 000 lives annually. The major burden of disease is carried by developing nations and Indigenous populations within developed nations, including Australia. This review will focus on the epidemiology, pathogenesis and treatment of ARF and RHD in Australia, where: streptococcal pyoderma, rather than streptococcal pharyngitis, and Group C and Group G Streptococcus, have been implicated as antecedents to ARF; the rates of RHD in remote Indigenous communities are persistently among the highest in the world; government register-based programs coordinate disease screening and delivery of prophylaxis with variable success; and researchers are making significant progress in the development of a broad-spectrum vaccine against Strep A.

School-based Streptococcal A Sore-throat Treatment Programs and Acute Rheumatic Fever Amongst Indigenous Māori: A Retrospective Cohort Study

BACKGROUND

Acute rheumatic fever (ARF) predominantly affects indigenous Māori schoolchildren in Bay of Plenty region, and more so male Māori students, especially when socioeconomically deprived. We evaluated the effectiveness of strategies for reducing ARF with group A streptococcal pharyngitis treatment in 2011-18.

METHODS

We retrospectively assessed outcomes of 3 open cohorts of Māori schoolchildren receiving different interventions: Eastern Bay rural Cohort 1, mean deprivation decile 9.80, received school-based sore-throat programs with nurse and general practice (GP) support; Eastern Whakatane township/surrounds Cohort 2, mean deprivation 7.25, GP management; Western Bay Cohort 3, mean deprivation 5.98, received predominantly GP care, but 3 highest-risk schools received school-based programs. Cases were identified from ICD10 ARF-coded hospital discharges, notifications to Ministry of Health, and a secondary-prevention penicillin database. Primary outcomes were first-presentation ARF cohorts' incidence preintervention (2000-10) and postintervention (2011-18) with cases over annual school rolls' Māori students-year denominators.

RESULTS

Overall, ARF in Maori schoolchildren declined in the cohorts with school-based programs. Cohort 1 saw a postintervention (2011-18) decline of 60%, 148 to 59/100,000/year, rate ratio (RR) = 0.40(CI 0.22-0.73) P = 0.002. Males' incidence declined 190 to 78 × 100,000/year RR = 0.41(CI 0.19-0.85) P = 0.013 and females too, narrowing gender disparities. Cohort 3 ARF incidence decreased 48%, 50 to 26/100,000/year RR = 0.52(CI 0.27-0.99) P = 0.044. In contrast, ARF doubled in Cohort 2 students with GP-only care without school-based programs increasing 30 to 69/100,000/year RR = 2.28(CI 0.99-5.27) P = 0.047, especially for males 39/100,000/year to 107/100,000/year RR = 2.71(CI 1.00-7.33) P = 0.0405.

CONCLUSIONS

School-based programs with indigenous Māori health workers' sore-throat swabbing and GP/Nurse support reduced first-presentation ARF incidence in Māori students in highest-risk settings.

Dissecting Streptococcus pyogenes interaction with human

Streptococcus pyogenes is a species of Gram-positive bacteria. It is also known as Group A Streptococcus (GAS) that causes pathogenesis to humans only. The GAS infection has several manifestations including invasive illness. Current research has linked the molecular modes of GAS virulence with substantial sequencing determinations for the isolation of genomes. These advances help to comprehend the molecular evolution resulting in the pandemic strains. Thus, it is indispensable to reconsider the philosophy that involves GAS pathogenesis. The recent investigations involve studying GAS in the nasopharynx and its capability to cause infection or asymptomatically reside in the host. These advances have been discussed in this article with an emphasis on the natural history of GAS and the evolutionary change in the pandemic strains. In addition, this review describes the unique functions for major pathogenicity determinants to comprehend their physiological effects.

Clinical Features of Group A Streptococcus in Children With Pharyngitis: Carriers versus Acute Infection

BACKGROUND

Among children with pharyngitis who test positive for group A Streptococcus (GAS), 10%-25% are GAS carriers. Current laboratory methods cannot distinguish acute infection from colonization.

METHODS

We examined 2 separate longitudinal studies of children with symptomatic pharyngitis associated with a positive GAS throat culture (illness culture). In cohort 1, children presented with pharyngitis symptoms to a clinician, then had follow-up cultures at regular intervals. In cohort 2, throat cultures were performed at regular intervals and with pharyngitis symptoms. Illness cultures were categorized as acute infection or carrier based on follow-up culture results. In cohort 2, carriers were further categorized as a GAS carrier with a new emm-type or a GAS carrier with a previous emm-type based on typing data from prior culture results. For each cohort, symptoms were compared at the time of illness culture between carriers and those with acute infection.

RESULTS

Cohort 1 (N = 75 illness cultures): 87% of the children were classified as acutely infected versus 13% carriers. Carriers were more likely to have upper respiratory (URI) symptoms [odds ratio (OR): 5.5; 95% confidence interval (CI): 1.4-22.1], headache (OR: 6.0; 95% CI: 1.2-40.5) or vomiting (OR: 5.5; 95% CI: 1.2-24.5). Cohort 2 (N = 122 illness cultures): 79% were acutely infected and 21% were carriers. Children determined to be carriers with a previous detected emm-type were more likely to have URI symptoms compared with those with acquisition of a new emm-type.

CONCLUSIONS

Children with symptomatic pharyngitis and GAS on throat culture identified as carriers were more likely to present with URI and atypical symptoms than children who were acutely infected.

The effect of group A streptococcal carrier on the epidemic model of acute rheumatic fever

Background

Group A streptococcus (GAS) is the most frequent cause of bacterial pharyngitis in school-aged children. The postinfection sequel as acute rheumatic fever (ARF) and rheumatic heart disease that cause morbidity and mortality among young people is public health concerns in several developing countries. Asymptomatic carriage state of GAS is not fully understood in terms of host and bacterial factors. Although the ability of transmitting GAS of the asymptomatic carriers is relatively low, they may present the reservoir of the epidemic. A fraction of GAS carriers is difficult to estimate in practice and may greatly vary between populations. Understanding the role of carriage on the transmission dynamic of GAS is important for assessing the public health impact of the ARF.

Method

This study investigates the effect of GAS carriers on both the transmission and dynamic of ARF cases by using a mathematical model.

Result

We derive the sufficient conditions for which the GAS can spread or extinct from the naive population under the variation of the fraction of symptomatic cases over the incidence of GAS. The threshold is possible to occur in general, but the last condition which is rather restrictive and involves parameter uncertainty. The increasing of carriers in the endemic state leads to the reduction in magnitude of the reproduction number and the number of ARF patients. We demonstrate that the adjustment of parameters can be carried out by the use of endemic state and some specific data.

Conclusion

We show theoretically that the presence of asymptomatic carriers may induce the epidemic threshold and reduce the virulence of GAS and the prevalence of ARF.

Understanding group A streptococcal pharyngitis and skin infections as causes of rheumatic fever: protocol for a prospective disease incidence study

BACKGROUND

Group A Streptococcal (GAS) infections cause the autoimmune disease acute rheumatic fever (ARF), which can progress to chronic rheumatic heart disease (RHD). Treating pharyngitis caused by GAS with antibiotics is important in preventing ARF. However, it is difficult to distinguish these infections from GAS carriers. There is growing evidence for GAS skin infections as a cause of ARF. This study will identify the incidence of true GAS pharyngitis and serological responses to GAS skin infections. The effectiveness of antibiotics for these conditions will be explored, and modifiable risk factors. Serum antibody titres indicating the upper limits of normal (ULN for ASO/ADB antibodies) will be established alongside carriage rates in asymptomatic children.

METHODS

This is a prospective disease incidence study, with an associated case-control study. The study population includes 1000 children (5-14 years) from Auckland, New Zealand, 800 of whom have visited their healthcare professional, resulting in a throat or skin swab for GAS, and 200 who are asymptomatic. The conditions of interest are GAS throat swab positive pharyngitis (n = 200); GAS carriage (n = 200); GAS negative throat swab (n = 200); GAS skin infections (n = 200); and asymptomatic controls (n = 200). All participants, except asymptomatic controls, will have acute and convalescent serological testing for ASO/ADB titres (collected < 9 days, and 2-4 weeks following symptom onset, respectively), alongside viral PCR from throat swabs. Asymptomatic controls will have ASO/ADB titres measured in one blood specimen and a throat swab for microbial culture. Caregivers of children will be interviewed using a questionnaire and any GAS isolates identified will be emm typed. The persistence of GAS antibodies will also be investigated.

DISCUSSION

Findings from this study will fill critical gaps in scientific knowledge to better understand the pathophysiology of ARF, improve clinical management of GAS infections, and design more effective ARF prevention programmes. In particular it will measure the incidence of true, serologically confirmed GAS pharyngitis; assess the immune response to GAS skin infections and its role as a cause of ARF; examine the effectiveness of oral antibiotics for treating GAS pharyngitis and carriage; and identify whether risk factors for GAS infections might provide intervention points for reducing ARF.

Transcriptomic Analysis of Streptococcus pyogenes Colonizing the Vaginal Mucosa Identifies hupY, an MtsR-Regulated Adhesin Involved in Heme Utilization

Colonization of the host requires the ability to adapt to an environment that is often low in essential nutrients such as iron. Here we present data showing that the transcriptome of the important human pathogen Streptococcus pyogenes shows extensive remodeling during in vivo growth, resulting in, among many other differentially expressed genes and pathways, a significant increase in genes involved in acquiring iron from host heme. Data show that HupY, previously characterized as an adhesin in both S. pyogenes and the related pathogen Streptococcus agalactiae, binds heme and affects intracellular iron concentrations. HupY, a protein with no known heme binding domains, represents a novel heme binding protein playing an important role in bacterial iron homeostasis as well as vaginal colonization.

Streptococcus pyogenes (group A streptococcus [GAS]) is a serious human pathogen with the ability to colonize mucosal surfaces such as the nasopharynx and vaginal tract, often leading to infections such as pharyngitis and vulvovaginitis. We present genome-wide transcriptome sequencing (RNASeq) data showing the transcriptomic changes GAS undergoes during vaginal colonization. These data reveal that the regulon controlled by MtsR, a master metal regulator, is activated during vaginal colonization. This regulon includes two genes highly expressed during vaginal colonization, hupYZ. Here we show that HupY binds heme in vitro, affects intracellular concentrations of iron, and is essential for proper growth of GAS using hemoglobin or serum as the sole iron source. HupY is also important for murine vaginal colonization of both GAS and the related vaginal colonizer and pathogen Streptococcus agalactiae (group B streptococcus [GBS]). These data provide essential information on the link between metal regulation and mucosal colonization in both GAS and GBS.

Modeling Streptococcus pyogenes Pharyngeal Colonization in the Mouse

Streptococcus pyogenes, or Group A Streptococcus (GAS), is a human-restricted pathogen most commonly found in the posterior oropharynx of the human host. The bacterium is responsible for 600 million annual cases of pharyngitis globally and has been found to asymptomatically colonize the pharynxes of 4-30% of the population. As such, many studies have utilized animals as models in order to decipher bacterial and host elements that contribute to the bacterial-pharyngeal interaction and determine differences between acute infection and asymptomatic colonization. The aim of this review is to first describe both bacterial and host factors that are important for the pharyngeal persistence of GAS in humans, then to detail the bacterial and host factors that are important for colonization in murine model, and finally to compare the two in order to evaluate the strength of murine pharyngeal colonization as a model for the human-GAS pharyngeal interaction.

Increased Risk for Invasive Group A Streptococcus Disease for Household Contacts of Scarlet Fever Cases, England, 2011-2016

The incidence of scarlet fever in England and Wales is at its highest in 50 years. We estimated secondary household risk for invasive group A Streptococcus (iGAS) disease within 60 days after onset of scarlet fever. Reports of scarlet fever in England during 2011–2016 were matched by residential address to persons with laboratory-confirmed iGAS infections. We identified 11 iGAS cases in ≈189,684 household contacts and a 60-day incidence rate of 35.3 cases/100,000 person-years, which was 12.2-fold higher than the background rate (2.89). Infants and contacts >75 years of age were at highest risk. Three cases were fatal; sepsis and cellulitis were the most common manifestations. Typing for 6 iGAS cases identified emm 1.0 (n = 4), emm 4.0 (n = 1), and emm 12.0 (n = 1). Although absolute risk in household contacts was low, clinicians assessing household contacts should be aware of the risk to expedite diagnosis and initiate life-saving treatment.

Intracellular Streptococcal Uptake and Persistence: A Potential Cause of Erysipelas Recurrence

Erysipelas is a severe streptococcal infection of the skin primarily spreading through the lymphatic vessels. Penicillin is the treatment of choice. The most common complication consists in relapses which occur in up to 40% or more of patients despite appropriate antibiotic treatment. They cause lymphatic damage resulting in irreversible lymphedema and ultimately elephantiasis nostras and lead to major health restrictions and high socio-medical costs. Prevention of relapses is an unmet need, because even long-term prophylactic penicillin application does eventually not reduce the risk of recurrence. In this article we assess risk factors and causes of erysipelas recurrence. A systematic literature search for clinical studies addressing potential causes and measures for prevention of erysipelas recurrence was combined with a review of experimental and clinical data assessing the ability and clinical relevance of streptococci for intracellular uptake and persistence. The literature review found that venous insufficiency, lymphedema, and intertrigo from fungal infections are considered to be major risk factors for recurrence of erysipelas but cannot adequately explain the high recurrence rate. As hitherto unrecognized likely cause of erysipelas relapses we identify the ability of streptococci for intracellular uptake into and persistence within epithelial and endothelial cells and macrophages. This creates intracellular streptococcal reservoirs out of reach of penicillins which do not reach sufficient bactericidal intracellular concentrations. Incomplete streptococcal elimination due to intracellular streptococcal persistence has been observed in various deep tissue infections and is considered as cause of relapsing streptococcal pharyngitis despite proper antibiotic treatment. It may also serves as endogenous infectious source of erysipelas relapses. We conclude that the current antibiotic treatment strategies and elimination of conventional risk factors employed in erysipelas management are insufficient to prevent erysipelas recurrence. The reactivation of streptococcal infection from intracellular reservoirs represents a plausible explanation for the frequent occurrence erysipelas relapses. Prevention of erysipelas relapses therefore demands for novel antibiotic strategies capable of eradicating intracellular streptococcal persistence.

Infections of the Neck

Infection of the neck is a relatively common emergency department complaint. If not diagnosed and managed promptly, it may quickly progress to a life-threatening infection. These infections can result in true airway emergencies that may require fiberoptic or surgical airways. This article covers common, as well as rare but emergent, presentations and uses an evidence-based approach to discuss diagnostic and treatment modalities.

Effect of Oral Probiotic Streptococcus salivarius K12 on Group A Streptococcus Pharyngitis: A Pragmatic Trial in Schools

BACKGROUND

The aim of this study was to examine effectiveness of oral probiotic Streptococcus salivarius K12 in preventing group A streptococcus pharyngitis in 5- to 14-year-old children at high risk of acute rheumatic fever. New Zealand has high rates of acute rheumatic fever among Māori and Pacific children. Children were already enrolled in a school-based Ministry of Health throat swabbing and treatment program. Children self-identified and reported sore throats daily and were swabbed twice weekly.

METHODS

A total of 1314 children were quasirandomized (based on odd or even birthdates) to receive either K12 (2.5 × 10(9) cfu per lozenge) or placebo lozenges and continued observed daily treatment (in the school week, during school time) for one school year.

RESULTS

A total of 801 children (61.0%) reported a sore throat on one or more occasions resulting in 2927 pharyngeal swabs. Of these swabs, 1525 (52.1%) were taken from 411 children receiving K12 and 119 (7.8%) of these were positive for group A streptococcus on routine culture. In addition, 1402 (47.8%) swabs were taken from 390 children receiving placebo and 124 (8.8%) were positive. Overall there was a nonsignificant 11.2% relative reduction in positive swabs among children receiving K12. This relative reduction was greater for older children, 7-9 years of age, 15.6%, and for children 10 years and older, 30.2%.

CONCLUSIONS

S. salivarius K12 had modest nonsignificant effects on culture-positive sore throats when given at school, during the school day. Based on our pragmatic trial, the routine use of this probiotic in the prevention of pharyngitis associated with GAS detection is not supported.

Acute Pharyngitis Associated With Streptococcus dysgalactiae Subspecies equisimilis in Children

BACKGROUND AND OBJECTIVES

The importance of Streptococcus dysgalactiae subsp. equisimilis (SDSE) in causing sporadic pharyngitis in children remains controversial. The aims of this study were (1) to report the incidence and (2) to compare the epidemiologic and clinical features of patients with SDSE to those with Streptococcus pyogenes (SP).

METHODS

A prospective study was conducted on acute pharyngitis associated with SDSE in children over a 2-year period. SDSE was identified using a phenotypic method, M protein gene (emm) analysis and matrix-assisted laser desorption ionization-time of flight mass spectrometry. Patients with positive SDSE or SP cultures received cephalosporins for 5 days and were followed up. The emm genotyping and specific virulence genes analyses were performed.

RESULTS

From 3416 throat cultures, 67 isolates (2.0%) were identified as SDSE and 515 (15.1%) were identified as SP. The mean age of patients with SDSE (8.3 years) was older than those with SP (6.6 years; P < 0.01). There was minimal seasonal variation in the isolation rates of SDSE. The febrile patients' rates, gender distribution, cervical lymph node adenopathy rates, hospitalization rates, eradication and failure rates and the nonsuppurative sequelae between patients with SDSE and SP were similar. All SDSE isolates possessed important virulence genes. The emm genotyping of SDSE showed high strain diversity.

CONCLUSIONS

The incidence of acute pharyngitis associated with accurately identified SDSE was 2/15 of that with SP. Epidemiologic and clinical features of acute pharyngitis associated with SDSE are indistinguishable from those with SP, with the exception of age and seasonal variation.

Prolonged and large outbreak of invasive group A Streptococcus disease within a nursing home: repeated intrafacility transmission of a single strain

OBJECTIVES

Multiple invasive group A Streptococcus (GAS) infections were reported to public health by a skilled nursing facility (facility A) in Illinois between May 2014 and August 2016. Cases continued despite interventions including antibiotic prophylaxis for all residents and staff. Two other geographically close facilities reported contemporaneous outbreaks of GAS. We investigated potential reasons for ongoing transmission.

METHODS

We obtained epidemiologic data from chart review of cases and review of facility and public health records from previous investigations into the outbreak. Infection control practices at facility A were observed and evaluated. Whole genome sequencing followed by phylogenetic analysis was performed on available isolates from the three facilities.

RESULTS

From 2014 to 2016, 19 invasive and 60 noninvasive GAS infections were identified at facility A occurring in three clusters. Infection control evaluations during clusters 2 and 3 identified hand hygiene compliance rates of 14% to 25%, appropriate personal protective equipment use in only 33% of observed instances, and deficient wound-care practices. GAS isolates from residents and staff of all three facilities were subtype emm89.0; on phylogenetic analysis, facility A isolates were monophyletic and distinct.

CONCLUSIONS

Inadequate infection control and improper wound-care practices likely led to this 28-month-long outbreak of severe infections in a skilled nursing facility. Whole genome sequencing and phylogenetic analysis suggested that intrafacility transmission of a single highly transmissible GAS strain was responsible for the outbreak in facility A. Integration of genomic epidemiology tools with traditional epidemiology and infection control assessments was helpful in investigation of a facility-wide outbreak.

Group A Streptococcus pharyngitis and pharyngeal carriage: A meta-analysis

Objective

Antibiotic treatment of Group A Streptococcus (GAS) pharyngitis is important in acute rheumatic fever (ARF) prevention, however clinical guidelines for prescription vary. GAS carriers with acute viral infections may receive antibiotics unnecessarily. This review assessed the prevalence of GAS pharyngitis and carriage in different settings.

Methods

A random-effects meta-analysis was performed. Prevalence estimates for GAS+ve pharyngitis, serologically-confirmed GAS pharyngitis and asymptomatic pharyngeal carriage were generated. Findings were stratified by age group, recruitment method and country income level. Medline and EMBASE databases were searched for relevant literature published between 1 January 1946 and 7 April 2017. Studies reporting prevalence data on GAS+ve or serologically-confirmed GAS pharyngitis that stated participants exhibited symptoms of pharyngitis or upper respiratory tract infection (URTI) were included. Included studies reporting the prevalence of asymptomatic GAS carriage needed to state participants were asymptomatic.

Results

285 eligible studies were identified. The prevalence of GAS+ve pharyngitis was 24.1% (95% CI: 22.6–25.6%) in clinical settings (which used ‘passive recruitment’ methods), but less in sore throat management programmes (which used ‘active recruitment’, 10.0%, 8.1–12.4%). GAS+ve pharyngitis was more prevalent in high-income countries (24.3%, 22.6–26.1%) compared with low/middle-income countries (17.6%, 14.9–20.7%). In clinical settings, approximately 10% of children swabbed with a sore throat have serologically-confirmed GAS pharyngitis, but this increases to around 50–60% when the child is GAS culture-positive. The prevalence of serologically-confirmed GAS pharyngitis was 10.3% (6.6–15.7%) in children from high-income countries and their asymptomatic GAS carriage prevalence was 10.5% (8.4–12.9%). A lower carriage prevalence was detected in children from low/middle income countries (5.9%, 4.3–8.1%).

Conclusions

In active sore throat management programmes, if the prevalence of GAS detection approaches the asymptomatic carriage rate (around 6–11%), there may be little benefit from antibiotic treatment as the majority of culture-positive patients are likely carriers.

Treating sore throats caused by Group A Streptococcus infections (GAS pharyngitis) with antibiotics is important for preventing acute rheumatic fever (ARF). It is impossible to distinguish patients with true GAS pharyngitis infections from GAS carriers with pharyngitis caused by viral infections when throat swab culturing alone is used to diagnose GAS pharyngitis. Carriers are not likely to benefit from antibiotic treatment, but may receive treatment unnecessarily. Reported rates of GAS pharyngitis and carriage vary considerably depending on the setting. Thus it is difficult to ascertain which groups are likely to benefit significantly from active sore throat management programmes which treat GAS pharyngitis in order to prevent ARF. We performed a meta-analysis to estimate the prevalence of GAS pharyngitis and asymptomatic carriage in different settings. Approximately 10% of all children swabbed for a sore throat in clinical settings have true GAS pharyngitis, but this increases to around 55% if the children have GAS detected in their throat using swab cultures. In active sore throat management programmes, the prevalence of GAS detection is lower than in clinical settings and if it declines towards 8% (the asymptomatic carriage level), there may be little benefit in treating GAS culture-positive patients with antibiotics.

Pediatric psoriasis: Evolving perspectives

BACKGROUND/OBJECTIVES

Childhood-onset psoriasis is a common skin disorder that has recently received increasing attention, particularly because of its significant medical, social, financial, and psychological burdens and its associated comorbidities. With limited data available and lack of standardized management guidelines for pediatric psoriasis, an expert panel desired to provide an updated critical overview and practical guidance for management of the affected population.

METHODS

A panel of pediatric dermatologists with extensive experience in pediatric psoriasis defined and prioritized a core set of topics, performed an English-language literature review, prepared critical evaluations and presentations of topic areas, and carried out a consensus meeting and follow-up consensus manuscript.

RESULTS

The summation of evolving perspectives in pediatric psoriasis includes epidemiology and natural history of the disease, precipitating factors and comorbidities, quality of life and burden of disease, clinical features and disease presentation, differential diagnosis, pathogenesis and treatment, including topical, photo, and systemic therapies.

CONCLUSION

Pediatric psoriasis is an important immune-mediated inflammatory skin disease with potential for significant impact on affected individuals and their caregivers. Current state-of-the-art care is based primarily on experience and expert consensus, but pediatric data are accumulating and therapeutic options are rapidly evolving.

Implications of asymptomatic carriers for infectious disease transmission and control

For infectious pathogens such as Staphylococcus aureus and Streptococcus pneumoniae, some hosts may carry the pathogen and transmit it to others, yet display no symptoms themselves. These asymptomatic carriers contribute to the spread of disease but go largely undetected and can therefore undermine efforts to control transmission. Understanding the natural history of carriage and its relationship to disease is important for the design of effective interventions to control transmission. Mathematical models of infectious diseases are frequently used to inform decisions about control and should therefore accurately capture the role played by asymptomatic carriers. In practice, incorporating asymptomatic carriers into models is challenging due to the sparsity of direct evidence. This absence of data leads to uncertainty in estimates of model parameters and, more fundamentally, in the selection of an appropriate model structure. To assess the implications of this uncertainty, we systematically reviewed published models of carriage and propose a new model of disease transmission with asymptomatic carriage. Analysis of our model shows how different assumptions about the role of asymptomatic carriers can lead to different conclusions about the transmission and control of disease. Critically, selecting an inappropriate model structure, even when parameters are correctly estimated, may lead to over- or under-estimates of intervention effectiveness. Our results provide a more complete understanding of the role of asymptomatic carriers in transmission and highlight the importance of accurately incorporating carriers into models used to make decisions about disease control.