Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 810
Filtrar
1.
Cureus ; 16(7): e63697, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39092363

RESUMO

Bacterial tracheitis (BT) is an uncommon life-threatening condition that results in acute upper airway obstruction. Classical signs include a toxic appearance, stridor, tachypnoea, and fever, often leading to rapid clinical deterioration. Recent studies have shown a shift in BT epidemiology and presentation, where stridor and respiratory distress are now predominant. A poor response to corticosteroids or nebulized epinephrine is also commonly described, along with a need for mechanical ventilation. We present the case of a five-year-old boy admitted to the emergency department with cough, stridor, and dyspnea that had significantly worsened over the previous hours. He presented reasonable general condition, marked retractions, poor air entry, stridor, and wheezing. Investigation revealed a slight elevation of C-reactive protein and leukocytosis with neutrophilia. Anteroposterior x-ray showed narrowing of subglottic airways (steeple sign). There was no response to oral/nebulized corticoids, nebulized adrenaline, or bag-valve-mask oxygenation. Antibiotic therapy with ceftriaxone was initiated. Due to deteriorating clinical conditions with severe respiratory acidosis, orotracheal intubation was required. Later Streptococcus pyogenes was isolated in the bronchial secretions and a targeted antibiotic regimen was administered. Progressive clinical and analytical improvement was observed with no complications. Although uncommon, BT remains a severe infectious condition affecting otherwise healthy children. Our case underscores the severity of the disease and the imperative for invasive interventions to achieve favorable outcomes. It also supports recent findings indicating a shift in predominant symptoms and prognosis. Clinicians must be vigilant and knowledgeable, recognizing that worsening stridor and respiratory distress unresponsive to conservative treatment are key indicators for diagnosing BT.

2.
Zhongguo Dang Dai Er Ke Za Zhi ; 26(8): 893-898, 2024 Aug 15.
Artigo em Chinês | MEDLINE | ID: mdl-39148397

RESUMO

Pharyngitis can be caused by various pathogens, including viruses and bacteria. Group A streptococcus (GAS) is the most common bacterial cause of pharyngitis. However, distinguishing GAS pharyngitis from other types of upper respiratory tract infections is challenging in clinical settings. This often leads to empirical treatments and, consequently, the overuse of antimicrobial drugs. With the advancement of antimicrobial drug management and healthcare payment reform initiatives in China, reducing unnecessary testing and prescriptions of antimicrobial drugs is imperative. To promote standardized diagnosis and treatment of GAS pharyngitis, this article reviews various international guidelines on the clinical diagnosis and differential diagnosis of GAS pharyngitis, particularly focusing on clinical scoring systems guiding laboratory testing and antimicrobial treatment decisions for GAS pharyngitis and their application recommendations, providing a reference for domestic researchers and clinical practitioners.


Assuntos
Faringite , Infecções Estreptocócicas , Streptococcus pyogenes , Humanos , Faringite/microbiologia , Faringite/tratamento farmacológico , Faringite/diagnóstico , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/tratamento farmacológico
3.
J Hand Surg Eur Vol ; : 17531934241268983, 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39169775

RESUMO

We highlight an increase in the number of invasive Group A streptococcal soft tissue infections and present the impact of those on the hand surgery service, based on a single Hand Unit experience at the Pulvertaft Hand Centre.

4.
Cureus ; 16(7): e65461, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39184708

RESUMO

Background and objectives Group A Streptococcus (GAS) is the most frequent cause of bacterial pharyngitis, and it is advised to selectively use rapid antigen detection testing (RADT). Currently, the decision to perform this test is based on pediatricians' observations, but the criteria are not well-defined. Therefore, we utilized unsupervised learning to categorize patients based on the clinical manifestations of GAS pharyngitis. Our goal was to pinpoint the clinical symptoms that should prompt further examination and treatment in patients diagnosed with pharyngitis. Methods We analyzed categorical data from 305 RADT-positive patients aged three to 15 years using the K-modes clustering method. Each explanatory variable's relationship with cluster variables was statistically examined. Finally, we tested the differences between clusters for continuous variables statistically. Results The K-modes method categorized the cases into two clusters. Cluster 1 included older children with lymph node tenderness, while Cluster 2 consisted of younger children with cough and rhinorrhea. Conclusion Differentiating streptococcal pharyngitis from common cold or upper respiratory tract infection based on clinical symptoms alone is challenging, particularly in young patients. Future research should focus on identifying indicators that can aid in suspecting streptococcal infection in young patients.

5.
Front Med (Lausanne) ; 11: 1438624, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39185468

RESUMO

Streptococcus is one of the common pathogens of suppurative infections. Invasive group A Streptococcus (iGAS) infections often develop from skin or soft tissue infections, and streptococcal toxic shock syndrome is considered the main cause of death in Chinese children with iGAS infectious disease. However, soft tissue infections caused by iGAS infections, especially the formation of abscesses, are relatively rare. A retrospective study was conducted, and pediatric in-patients who were diagnosed with an iGAS infection identified by cultures from normally sterile sites and treated in a tertiary hospital during 2016-2018 were included. A total of 14 patients were identified, which included 10 boys and four girls. The patients had an age range from 3 months to 10 years and were diagnosed with soft tissue infections and a formation of abscesses caused by iGAS infections. The most common sites of infections were the lower limbs. In five patients, the abscess was accompanied by fever, and the local soft tissue showed redness, swelling, tenderness, and an elevated skin temperature. Laboratory findings included an increased white blood cell (WBC) count in 12 patients, an increased C reactive protein (CRP) level in seven patients, and an increased erythrocyte sedimentation rate (ESR) in 10 patients. No patients had an elevated procalcitonin level. For all 14 patients, we performed puncture and drainage of abscesses, and cultured GAS from the drainage fluid. All children also received antibiotic treatment. During 2 months of follow-up, the patients' condition remained stable and no evidence of kidney or heart damage was observed. For pediatric patients with abscesses, early diagnosis, prompt treatment with incision and drainage, and immediate culture of the drainage fluid are important. Upon confirmation of an iGAS infection, ß-lactam antibiotics should be given to provide effective treatment, and in some patients with poor therapeutic outcomes, the use of vancomycin as an alternative can achieve the desired results.

6.
Microb Genom ; 10(8)2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39133528

RESUMO

At the end of 2022 into early 2023, the UK Health Security Agency reported unusually high levels of scarlet fever and invasive disease caused by Streptococcus pyogenes (StrepA or group A Streptococcus). During this time, we collected and genome-sequenced 341 non-invasive throat and skin S. pyogenes isolates identified during routine clinical diagnostic testing in Sheffield, a large UK city. We compared the data with that obtained from a similar collection of 165 isolates from 2016 to 2017. Numbers of throat-associated isolates collected peaked in early December 2022, reflecting the national scarlet fever upsurge, while skin infections peaked later in December. The most common emm-types in 2022-2023 were emm1 (28.7 %), emm12 (24.9 %) and emm22 (7.7 %) in throat and emm1 (22 %), emm12 (10 %), emm76 (18 %) and emm49 (7 %) in skin. While all emm1 isolates were the M1UK lineage, the comparison with 2016-2017 revealed diverse lineages in other emm-types, including emm12, and emergent lineages within other types including a new acapsular emm75 lineage, demonstrating that the upsurge was not completely driven by a single genotype. The analysis of the capsule locus predicted that only 51 % of throat isolates would produce capsule compared with 78% of skin isolates. Ninety per cent of throat isolates were also predicted to have high NADase and streptolysin O (SLO) expression, based on the promoter sequence, compared with only 56% of skin isolates. Our study has highlighted the value in analysis of non-invasive isolates to characterize tissue tropisms, as well as changing strain diversity and emerging genomic features which may have implications for spillover into invasive disease and future S. pyogenes upsurges.


Assuntos
Infecções Estreptocócicas , Streptococcus pyogenes , Streptococcus pyogenes/genética , Streptococcus pyogenes/classificação , Streptococcus pyogenes/isolamento & purificação , Humanos , Reino Unido , Infecções Estreptocócicas/microbiologia , Proteínas da Membrana Bacteriana Externa/genética , Antígenos de Bactérias/genética , Faringe/microbiologia , Escarlatina/microbiologia , Escarlatina/epidemiologia , Proteínas de Transporte/genética , Estreptolisinas/genética , Sequenciamento Completo do Genoma/métodos , Proteínas de Bactérias/genética , Filogenia , Criança , Adulto , NAD+ Nucleosidase/genética , NAD+ Nucleosidase/metabolismo , Pele/microbiologia , Pré-Escolar , Masculino
7.
Int J Mol Sci ; 25(15)2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39125755

RESUMO

The recent increase in Group A Streptococcus (GAS) incidences in several countries across Europe and some areas of the Unites States (U.S.) has raised concerns. To understand GAS diversity and prevalence, we conducted a local genomic surveillance in Eastern North Carolina (ENC) in 2022-2023 with 95 isolates and compared its results to those of the existing national genomic surveillance in the U.S. in 2015-2021 with 13,064 isolates. We observed their epidemiological changes before and during the COVID-19 pandemic and detected a unique sub-lineage in ENC among the most common invasive GAS strain, ST28/emm1. We further discovered a multiple-copy insertion sequence, ISLgar5, in ST399/emm77 and its single-copy variants in some other GAS strains. We discovered ISLgar5 was linked to a Tn5801-like tetM-carrying integrative and conjugative element, and its copy number was associated with an ermT-carrying pRW35-like plasmid. The dynamic insertions of ISLgar5 may play a vital role in genome fitness and adaptation, driving GAS evolution relevant to antimicrobial resistance and potentially GAS virulence.


Assuntos
Infecções Estreptocócicas , Streptococcus pyogenes , Streptococcus pyogenes/genética , Streptococcus pyogenes/patogenicidade , North Carolina/epidemiologia , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/microbiologia , Humanos , Genoma Bacteriano , COVID-19/epidemiologia , COVID-19/virologia , Genômica/métodos , Filogenia , Elementos de DNA Transponíveis/genética , SARS-CoV-2/genética
8.
Vaccine ; 42(22): 126205, 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39141987

RESUMO

BACKGROUND: Group A Streptococcus (Strep A) causes both uncomplicated and severe invasive infections, as well as the post-infection complications acute rheumatic fever and rheumatic heart disease. Despite the high global burden of disease resulting from Strep A infections, there is not a licensed vaccine. A 30-valent M protein-based vaccine has previously been shown to be immunogenic in animal models and in a Phase I clinical trial (NCT02564237). Here, we assessed the immunogenicity of a 30-valent messenger (m)RNA vaccine designed to express the same M peptide targets as the 30-valent protein vaccine and compared it with the protein vaccine. METHODS: Female New Zealand white rabbits were immunized with one of four vaccine formulations (3 doses of each formulation at days 1, 28, and 56): soluble mRNA (100 µg/animal), C-terminal transmembrane mRNA (100 µg/animal), protein vaccine (400 µg/animal), or a non-translatable RNA control (100 µg/animal). Serum was collected one day prior to the first dose and on days 42 and 70. Rabbit serum samples were assayed for antibody levels against synthetic M peptides by ELISA. HL-60 opsonophagocytic killing (OPK) assays were performed to assess functional antibody levels. RESULTS: Serum IgG levels were similar for the mRNA and protein vaccines. The CtTM version of the mRNA vaccine elicited slightly higher antibody levels than the mRNA designed to express soluble proteins. OPK activity was similar for the mRNA and protein vaccines, regardless of M type. CONCLUSIONS: The total antibody responses and functional antibody levels elicited by the 30-valent mRNA Strep A vaccines were similar to those observed following immunization with the analogous protein vaccine. The mRNA vaccine platform provides potential advantages to protein-based vaccines including inherent adjuvant activity, increased production efficiency, lower cost, and the potential to rapidly change epitopes/peptides, all of which are important considerations related to multivalent Strep A vaccine development.


Assuntos
Anticorpos Antibacterianos , Antígenos de Bactérias , Infecções Estreptocócicas , Vacinas Estreptocócicas , Streptococcus pyogenes , Animais , Coelhos , Feminino , Vacinas Estreptocócicas/imunologia , Vacinas Estreptocócicas/administração & dosagem , Vacinas Estreptocócicas/genética , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Infecções Estreptocócicas/prevenção & controle , Infecções Estreptocócicas/imunologia , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/genética , Streptococcus pyogenes/imunologia , Streptococcus pyogenes/genética , Imunogenicidade da Vacina , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Transporte/imunologia , Proteínas de Transporte/genética , Vacinas Sintéticas/imunologia , Vacinas Sintéticas/administração & dosagem , RNA Mensageiro/genética , RNA Mensageiro/imunologia
9.
Open Forum Infect Dis ; 11(8): ofae457, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39205925

RESUMO

M1UK is associated with current surges in invasive infection globally, partly due to increased production of superantigen streptococcal pyrogenic exotoxin A. We show that M1UK is now the dominant invasive emm1 lineage in Aotearoa New Zealand and is genomically related to community infections, suggesting that measures that effectively prevent group A Streptococcus pharyngitis in children could reduce invasive disease.

10.
mSphere ; : e0063424, 2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39189777

RESUMO

Group A Streptococcus (GAS) necrotizing fasciitis (NF) is a difficult-to-treat bacterial infection associated with high morbidity and mortality despite extensive surgery and targeted antibiotic treatment. Difficult-to-treat infections are often characterized by the presence of bacteria surviving prolonged antibiotic exposure without displaying genetic resistance, referred to as persisters. In the present study, we investigated the presence of GAS persisters in tissue freshly debrided from patients as well as in an in vivo mouse model of NF and examined the phenomenon of antibiotic tolerance. Time-lapse imaging of GAS plated directly upon isolation from NF debrided tissue and an antibiotic challenge-based persisters assay were used to assess the presence of persisters. We show for the first time that GAS recovered directly from freshly debrided NF tissue is characterized by heterogeneous and overall delayed colony appearance time, suggesting the presence of persisters. Acidic pH or nutrient stress exposure, mimicking the NF-like environment in vitro, led to a similar phenotypic heterogeneity and resulted in enhanced survival upon antibiotic challenge, confirming the presence of GAS persisters. GAS persisters might contribute to NF treatment failure, despite extensive surgery and adequate antibiotic treatment.IMPORTANCEDifficult-to-treat and recurrent infections are a global problem burdening society and the health care system alike. Unraveling the mechanisms by which bacteria can survive antibiotic treatment without developing genetic resistance is of utmost importance to lay the foundation for new, effective therapeutic approaches. For the first time, we describe the phenomenon of antibiotic tolerance in group A Streptococcus (GAS) isolated from necrotizing fasciitis (NF) patients. Dormant, non-replicating cells (persisters) are tolerant to antibiotics and their occurrence in vivo is reported in an increasing number of bacterial species. Tailored treatment options, including the use of persisters-targeting drugs, need to be developed to specifically target dormant bacteria causing difficult-to-treat and recurrent infections.

11.
J Clin Microbiol ; : e0076624, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39194268

RESUMO

Since 2022, many countries have reported an upsurge in invasive group A streptococcal (iGAS) infections. We explored whether changes in Streptococcus pyogenes carriage rates or emergence of strains with potentially altered virulence, such as emm1 variants M1UK and M1DK, contributed to the 2022/2023 surge in the Netherlands. We determined emm (sub)type distribution for 2,698 invasive and 351 S. pyogenes carriage isolates collected between January 2009 and March 2023. Genetic evolution of emm1 was analyzed by whole-genome sequencing of 497 emm1 isolates. The nationwide iGAS upsurge coincided with a sharp increase of emm1.0 from 18% (18/100) of invasive isolates in Q1 2022 to 58% (388/670) in Q1 2023 (Fisher's exact test, P < 0.0001). M1UK became dominant among invasive emm1 isolates in 2016 and further expanded from 72% in Q1 2022 to 96% in Q1 2023. Phylogenetic comparison revealed evolution and clonal expansion of four new M1UK clades in 2022/2023. DNase Spd1 and superantigen SpeC were acquired in 9% (46/497) of emm1 isolates. S. pyogenes carriage rates and emm1 proportions in carriage isolates remained stable during this surge, and the expansion of M1UK in iGAS was not reflected in carriage isolates. During the 2022/2023 iGAS surge in the Netherlands, expansion of four new M1UK clades was observed among invasive isolates, but not carriage isolates, suggesting increased virulence and fitness of M1UK compared to contemporary M1 strains. The emergence of more virulent clades has important implications for public health strategies such as antibiotic prophylaxis for close contacts of iGAS patients.IMPORTANCEThis study describes the molecular epidemiology of invasive group A streptococcal (iGAS) infections in the Netherlands based on >3,000 Streptococcus pyogenes isolates from both asymptomatic carriers and iGAS patients collected before, during, and after the COVID-19 pandemic period (2009-2023) and is the first to assess whether changes in carriage rates or carried emm types contributed to the alarming post-COVID-19 upsurge in iGAS infections. We show that the 2022/2023 iGAS surge coincided with a sharp increase of emm1, particularly the toxicogenic M1UK variant, in invasive isolates, but not in carriage isolates. These findings suggest that increased virulence and fitness of M1UK likely contributes to an increased dissemination between hosts. The emergence of a more virulent and fit lineage has important implications for iGAS control interventions such as antibiotic prophylaxis for close contacts of iGAS patients and calls for a reappraisal of iGAS control interventions and guidelines.

12.
Eur J Pediatr ; 2024 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-39215861

RESUMO

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.

13.
Intern Med ; 2024 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-38987181

RESUMO

Necrotizing fasciitis (NF) is a life-threatening disease with high mortality and rapidly progressive clinical manifestations1. Early detection and surgical management coupled with antibiotic treatment are crucial for the survival, and the patient survival is heavily dependent on clinical decisions2,3. However, it is not widely known that NF does not always follow a typical clinical course, and there have been no case reports of NF following an atypical clinical course. Although the course of the disease depends on the individual patient, it remains a challenge for physicians to determine the precise timing when patients are most likely to survive multiple surgical interventions. We encountered a challenging case presenting with an atypical clinical course. We herein report a 31-year-old man who followed a deteriorating biphasic-like clinical course and presented with extensive NF and streptococcal toxic shock syndrome due to Group A Streptococcus. This case serves to inform physicians of the existence of NF with an atypical and deteriorating biphasic-like clinical course, emphasizing the need for a careful evaluation of the patient condition.

14.
Access Microbiol ; 6(6)2024.
Artigo em Inglês | MEDLINE | ID: mdl-39045238

RESUMO

Group A streptococcus (GAS) can cause serious invasive disease in humans with a high mortality rate. An increase in GAS infections was reported in Ireland in 2022, and this increase has been sustained in 2023 and is paralleled by similar trends in Europe. Rising antimicrobial resistance is a global problem and presents significant challenges to clinicians treating GAS infection. There was a reported increase in clindamycin resistance in GAS isolates in Ireland in 2022. We examined antimicrobial susceptibility patterns of GAS isolates in our institution in 2022. Although all GAS isolates included in our study were susceptible to penicillin, we noted a high clindamycin resistance rate of 28 % in our invasive GAS isolates. We also noted high tetracycline and erythromycin resistance, 43 and 30 %, respectively. Our results could have implications for empiric antimicrobial prescribing guidelines for skin and soft tissue infections, which often include clindamycin as it inhibits the production of many virulence factors associated with GAS. In addition, macrolides are often the first line recommended antibiotic for patients with anaphylaxis to penicillin. This study emphasises the importance of continuous surveillance and antimicrobial susceptibility testing of invasive and non-invasive isolates in order to monitor trends in increasing antimicrobial resistance.

17.
J Surg Case Rep ; 2024(7): rjad708, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38966684

RESUMO

Necrotising fasciitis (NF) is a rare but life-threatening skin and soft tissue infection. It requires urgent surgical debridement. The most common cause of monomicrobial NF is invasive Group A Streptococcus (IGAS). We present eight patients who were all treated in a single trauma unit within a 9-month period. All cases required surgical debridement and had positive microbiology testing for IGAS. The eight patients did not present typically for NF, nor did they all have typical risk factors for the development of NF. The in-hospital mortality rate was 37.5%. This series represents an epidemiological spike of IGAS infections causing NF. The findings from this series could inform future practice if similar spikes were to be encountered.

18.
Infect Microbes Dis ; 6(2): 65-73, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38952747

RESUMO

Vitamin A and its biologically active derivative, retinoic acid (RA), are important for many immune processes. RA, in particular, is essential for the development of immune cells, including neutrophils, which serve as a front-line defense against infection. While vitamin A deficiency has been linked to higher susceptibility to infections, the precise role of vitamin A/RA in host-pathogen interactions remains poorly understood. Here, we provided evidence that RA boosts neutrophil killing of methicillin-resistant Staphylococcus aureus (MRSA). RA treatment stimulated primary human neutrophils to produce reactive oxygen species, neutrophil extracellular traps, and the antimicrobial peptide cathelicidin (LL-37). Because RA treatment was insufficient to reduce MRSA burden in an in vivo murine model of skin infection, we expanded our analysis to other infectious agents. RA did not affect the growth of a number of common bacterial pathogens, including MRSA, Escherichia coli K1 and Pseudomonas aeruginosa; however, RA directly inhibited the growth of group A Streptococcus (GAS). This antimicrobial effect, likely in combination with RA-mediated neutrophil boosting, resulted in substantial GAS killing in neutrophil killing assays conducted in the presence of RA. Furthermore, in a murine model of GAS skin infection, topical RA treatment showed therapeutic potential by reducing both skin lesion size and bacterial burden. These findings suggest that RA may hold promise as a therapeutic agent against GAS and perhaps other clinically significant human pathogens.

19.
Front Cell Infect Microbiol ; 14: 1337861, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39055978

RESUMO

Introduction: It is currently unclear what the role of Group A streptococcus (GAS) virulence factors (VFs) is in contributing to the invasive potential of GAS. This work investigated the evidence for the association of GAS VFs with invasive disease. Methods: We employed a broad search strategy for studies reporting the presence of GAS VFs in invasive and non-invasive GAS disease. Data were independently extracted by two reviewers, quality assessed, and meta-analyzed using Stata®. Results: A total of 32 studies reported on 45 putative virulence factors [invasive (n = 3,236); non-invasive (n = 5,218)], characterized by polymerase chain reaction (PCR) (n = 30) and whole-genome sequencing (WGS) (n = 2). The risk of bias was rated as low and moderate, in 23 and 9 studies, respectively. Meta-,analyses of high-quality studies (n = 23) revealed a significant association of speM [OR, 1.64 (95%CI, 1.06; 2.52)] with invasive infection. Meta-analysis of WGS studies demonstrated a significant association of hasA [OR, 1.91 (95%CI, 1.36; 2.67)] and speG [OR, 2.83 (95%CI, 1.63; 4.92)] with invasive GAS (iGAS). Meta-analysis of PCR studies indicated a significant association of speA [OR, 1.59 (95%CI, 1.10; 2.30)] and speK [OR, 2.95 (95%CI, 1.81; 4.80)] with invasive infection. A significant inverse association was observed between prtf1 [OR, 0.42 (95%CI, 0.20; 0.87)] and invasive infection. Conclusion: This systematic review and genomic meta-analysis provides evidence of a statistically significant association with invasive infection for the hasA gene, while smeZ, ssa, pnga3, sda1, sic, and NaDase show statistically significantly inverse associations with invasive infection. SpeA, speK, and speG are associated with GAS virulence; however, it is unclear if they are markers of invasive infection. This work could possibly aid in developing preventative strategies.


Assuntos
Infecções Estreptocócicas , Streptococcus pyogenes , Fatores de Virulência , Streptococcus pyogenes/genética , Streptococcus pyogenes/patogenicidade , Fatores de Virulência/genética , Infecções Estreptocócicas/microbiologia , Humanos , Virulência/genética , Sequenciamento Completo do Genoma , Proteínas de Bactérias/genética
20.
mBio ; 15(8): e0084024, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-38953375

RESUMO

While genome-wide transposon mutagenesis screens have identified numerous essential genes in the significant human pathogen Streptococcus pyogenes (group A Streptococcus or GAS), many of their functions remain elusive. This knowledge gap is attributed in part to the limited molecular toolbox for controlling GAS gene expression and the bacterium's poor genetic transformability. CRISPR interference (CRISPRi), using catalytically inactive GAS Cas9 (dCas9), is a powerful approach to specifically repress gene expression in both bacteria and eukaryotes, but ironically, it has never been harnessed for controlled gene expression in GAS. In this study, we present a highly transformable and fully virulent serotype M1T1 GAS strain and introduce a doxycycline-inducible CRISPRi system for efficient repression of bacterial gene expression. We demonstrate highly efficient, oligo-based single guide RNA cloning directly to GAS, enabling the construction of a gene knockdown strain in just 2 days, in contrast to the several weeks typically required. The system is shown to be titratable and functional both in vitro and in vivo using a murine model of GAS infection. Furthermore, we provide direct in vivo evidence that the expression of the conserved cell division gene ftsZ is essential for GAS virulence, highlighting its promise as a target for emerging FtsZ inhibitors. Finally, we introduce SpyBrowse (https://veeninglab.com/SpyBrowse), a comprehensive and user-friendly online resource for visually inspecting and exploring GAS genetic features. The tools and methodologies described in this work are poised to facilitate fundamental research in GAS, contribute to vaccine development, and aid in the discovery of antibiotic targets. IMPORTANCE: While group A Streptococcus (GAS) remains a predominant cause of bacterial infections worldwide, there are limited genetic tools available to study its basic cell biology. Here, we bridge this gap by creating a highly transformable, fully virulent M1T1 GAS strain. In addition, we established a tight and titratable doxycycline-inducible system and developed CRISPR interference (CRISPRi) for controlled gene expression in GAS. We show that CRISPRi is functional in vivo in a mouse infection model. Additionally, we present SpyBrowse, an intuitive and accessible genome browser (https://veeninglab.com/SpyBrowse). Overall, this work overcomes significant technical challenges of working with GAS and, together with SpyBrowse, represents a valuable resource for researchers in the GAS field.


Assuntos
Sistemas CRISPR-Cas , Infecções Estreptocócicas , Streptococcus pyogenes , Streptococcus pyogenes/genética , Streptococcus pyogenes/patogenicidade , Animais , Camundongos , Infecções Estreptocócicas/microbiologia , Virulência/genética , Regulação Bacteriana da Expressão Gênica , Modelos Animais de Doenças , Feminino , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA