Group A Streptococcal Infections Research Articles

Current scenario of recently rising up cases of invasive group A streptococcal (iGAS) infections in younger children in many European nations: clinical management and prospective counteracting measures – an update

Current scenario of recently rising up cases of invasive group A streptococcal (iGAS) infections in younger children in many European nations: clinical management and prospective counteracting measures – an update

The impact of rapid antigen detection test (RADT) for group A streptococcus on the antibiotic prescription: an observational study from a primary care setting in Lisbon

Introduction: Acute pharyngitis is a common diagnosis in primary care. Although viruses are the most common aetiology, antibiotic therapy is frequently prescribed. The inappropriate antibiotic prescription should be avoided to prevent antibiotic resistance. Many national and international guidelines recommend testing for group A streptococcus (GAS) before antibiotic treatment when clinical presentation suggests GAS infection. Aim: This study aims to describe the feasibility of the implementation of the rapid antigen detection test (RADT) in a primary care setting and its impact on antibiotic prescription. Secondary goals include the evaluation of possible associations between symptoms and RADT results. Methods: From October 2019 to March 2020, patients presenting with acute pharyngitis at USF do Parque were eligible. A questionnaire was applied to divide the individuals into four different groups (clearly viral, probably viral, diagnostic doubt, and probably bacterial), and to assess the previous intention to prescribe antibiotics. We applied 136 questionnaires and performed 133 RADT. Nursing staff classified the specimen collection process and result from interpretation according to its difficulty. The proportion of antibiotics avoided was estimated as the number of times physicians changed their intended antibiotic prescription following a negative RADT result. Results: Among the tests performed, 97.7% were easy to interpret. Without RADT, 45 patients were going to be prescribed an antibiotic. After the test result, 27 antibiotic prescriptions were avoided. Tonsil hypertrophy, palatal petechiae, and fever increased the odds of a positive RADT result. Cough was associated with a negative RADT result. Conclusions: This study showed that RADT is easy to implement and contributed to appropriate antibiotic prescription. Tonsil hypertrophy, palatal petechiae, and fever were significantly associated with a positive RADT result, and cough was associated with a negative RADT result. Primary care centers would benefit from having RADT available when there is strong suspicion or doubt of bacterial pharyngitis.

Scarlet fever and the dental team

Scarlet fever is a mild, but highly contagious disease caused by Group A Streptococcus (GAS) bacteria. Scarlet fever begins with flu-like symptoms and, within the first 12-48 hours, it is common for a rash to develop that feels like sandpaper to the touch. In rare cases, GAS bacteria can cause an invasive infection that can be fatal. Invasive GAS (iGAS) infection occurs when the bacteria are in a place of the body where they are not normally found, such as the blood stream. Scarlet fever is usually treated with antibiotics, which can reduce the chances of the patient developing iGAS and reduce the risk of them spreading the infection to others. The World Health Organization and UK Health Security Agency have announced that the number of scarlet fever and iGAS cases observed in children has been several times higher than pre-pandemic levels for the equivalent period of time. As healthcare professionals, it is important that the dental team understand key aspects of scarlet fever. Here, scarlet fever symptoms, transmission, clinical manifestations, antibiotic treatment, and risks to the dental team are reviewed. CPD/Clinical Relevance: To describe epidemiology of scarlet fever and discuss the implications for the dental team.

Structural basis underlying the synergism of NADase and SLO during group A Streptococcus infection

Group A Streptococcus (GAS) is a strict human pathogen possessing a unique pathogenic trait that utilizes the cooperative activity of NAD+-glycohydrolase (NADase) and Streptolysin O (SLO) to enhance its virulence. How NADase interacts with SLO to synergistically promote GAS cytotoxicity and intracellular survival is a long-standing question. Here, the structure and dynamic nature of the NADase/SLO complex are elucidated by X-ray crystallography and small-angle scattering, illustrating atomic details of the complex interface and functionally relevant conformations. Structure-guided studies reveal a salt-bridge interaction between NADase and SLO is important to cytotoxicity and resistance to phagocytic killing during GAS infection. Furthermore, the biological significance of the NADase/SLO complex in GAS virulence is demonstrated in a murine infection model. Overall, this work delivers the structure-functional relationship of the NADase/SLO complex and pinpoints the key interacting residues that are central to the coordinated actions of NADase and SLO in the pathogenesis of GAS infection.

La recrudescenza delle infezioni (anche) da streptococco beta-emolitico di gruppo A?

Since the beginning of December 2022, unusually high number of Group A Streptococcus (GAS) infec-tions among children have been reported across at least five Member States in the European Region (France, Ireland, Sweden, Holland and the United Kingdom). At the moment in Italy there has not yet been a report of an increase in cases of GAS infections, which could be either real or due to the lack of adequate monitoring. It is essential to implement adequate population monitoring systems also for GAS infections and pay particular attention to the clinical pictures that GAS can determine, both slight and dangerously invasive infections (iGAS). The increase in the cases of iGAS, as well as those from viral respiratory infections, is clearly related to the restrictions that have been adopted during the Covid-19 pandemic and only the return to the normal circulation of microbial agents will be able to avoid fur-ther infectious endemic clusters by restoring the “immune debt” phenomenon that has occurred.

Патогенетические механизмы тяжелых клинических форм стрептококковой инфекции у детей

Currently, there is a significant increase in the morbidity of streptococcal infections, including the severe cases with a fatal outcomes. In this article we show the general information on the modern features of diseases caused by Streptococcus pyogenes (Group A Streptococcal (GAS) Infections), pathogenicity factors of the microbe and its strain diversity. Various aspects of immunopathogenesis in various clinical forms of streptococcal infection, such as tonsillitis, acute rheumatic fever, toxic shock syndrome, neurological and myocardial complications are discussed. The issues of association between the severe course of GAS infection against the background of previous chickenpox, influenza, infectious mononucleosis are described. Possible mechanisms of interaction of pathogens in combined virus-streptococcal infection are presented. The ways of avoiding streptococcus from the host's protective reactions, the features of the innate and adaptive immune response in various clinical forms of streptococcal infections, as well as the role of viruses in the pathogenesis of severe disease in children are reflected. The tactics of pathogenetic therapy using the medicine of complex action cytoflavin, which allows optimizing the course of generalized streptococcal infection, is noted. Key words: streptococcal infections, viruses, immunopathogenesis, clinic, cytoflavin, strains

Group A Streptococcus Infections: Their Mechanisms, Epidemiology, and Current Scope of Vaccines.

Group A streptococci (GAS) are gram-positive, cocci-shaped bacteria that cause a wide variety of infections and are a cause of significant health burden, particularly in lower- and middle-income nations. The GAS genome contains a number of virulence factors such as the M-protein, hyaluronic acid, C5a peptidase, etc. Despite its significant health burden across the globe, a proper vaccine against GAS infections is not yet available. Various candidates for an effective GAS vaccine are currently being researched. These are based on various parts of the streptococcal genome. These include candidates based on the N-terminal region of the M protein, the conserved C-terminal region of the M protein, and other parts of the streptococcal genome. The development of a vaccine against GAS infections is hampered by certain challenges, such as extensive genetic heterogeneity and high protein sequence variation. This review paper sheds light on the various virulence factors of GAS, their epidemiology, the different vaccine candidates currently being researched, and the challenges associated with M-protein and non-M-protein-based vaccines. This review also sheds light on the current scenario regarding the status of vaccine development against GAS-related infections.

The efficacy and safety of a shortened duration of antimicrobial therapy for group A Streptococcus bacteremia

ObjectivesTo determine if shorter courses of antibiotic therapy for group A Streptococcus (GAS) bacteremia are associated with excess mortality. MethodsIn this retrospective study of consecutive cases of GAS bacteremia in tropical Australia, the duration of antibiotic therapy was correlated with 90-day all-cause mortality. ResultsThere were 286 episodes of GAS bacteremia; the patients’ median (interquartile range) age was 60 (48-71) years and 169/286 (59.1%) patients identified as an Indigenous Australian. There were 227/286 (79.4%) patients with a significant comorbidity. The all-cause 90-day mortality was 16/286 (5.6%); however, 12/16 (81.3%) patients died while still receiving their initial course of antibiotics and only 7/16 (43.8%) deaths were directly attributable to the GAS infection. After excluding patients who died while taking their initial course of antibiotics and those in whom the duration of therapy was uncertain, there was no difference in 90-day mortality between patients receiving ≤5 days of intravenous antibiotics and those receiving longer courses (1/137 [0.7%] vs 3/107 [2.8%], P-value = 0.32) nor in patients receiving ≤10 days of total therapy and those receiving longer courses (1/67 [1.5%] vs 3/178 [1.7%], P-value = 1.0). ConclusionEven among patients with significant comorbidity, shorter antibiotic courses for GAS bacteremia are not associated with excess mortality.

Pathogenetic correlation of severe sepsis and multiple organ dysfunction syndrome provoked by multiple infections in perinatal period of women

Introduction. Despite significant advances in diagnosis, medical management and antimicrobial therapy, sepsis in the puerperium remains an important cause of maternal morbidity and mortality. The abnormalities associated with the clinical syndrome of sepsis result from a nonspecific innate inflammatory response. This is due to the fact that sepsis represents a systemic inflammatory response syndrome (SIRS) to infection or injury; therefore, it can rapidly progress to septic shock and death despite aggressive treatment. Severe sepsis with MODS has a mortality rate of 20– 40%, rising to around 60% if septicemic shock develops. Symptoms of sepsis may be less distinctive than in the non-pregnant population and are not necessarily present in all cases; therefore, a high index of suspicion is necessary. The major pathogens causing sepsis in the puerperium are: group A streptococcus (GAS), also known as Streptococcus pyogenes, Escherichia coli, Staphylococcus aureus, Streptococcus pneumonia, methicillin-resistant S. aureus (MRSA), Clostridium septicum, Morganella morganii and antibiotic-resistant Stenotrophomonas Moltrophilia. Multiple risk factors for maternal sepsis have been identified: obesity, impaired glucose tolerance/diabetes, impaired immunity/immunosuppressant medication, anemia, vaginal discharge, history of pelvic infection, amniocentesis and other invasive procedures, cervical cerclage, prolonged spontaneous rupture of membranes, caesarean section, wound hematomas, retained products of conception, GAS infection, vaginal trauma. Material and methods. Presentation of case report using the following key-words: „infection”, „systemic inflammatory response syndrome (SIRS)”, „severe sepsis”, „septic shock”, „multiorgan dysfunction syndrome (MODS)”. Results. We present a case of perinatal infections complicated with MODS. Conclusions. The presence of pelvic hematomas triggers the sepsis caused by multiple infections in perinatal period and can significantly increase the morbidity related to bleeding, infection, surgery and blood product transfusion. The clinical situation may worsen in the presence of pre-existing pathological conditions before pregnancy.

Genome-Wide Transposon Mutagenesis Screens Identify Group A Streptococcus Genes Affecting Susceptibility to β-Lactam Antibiotics.

Group A streptococcus (GAS) is a Gram-positive human bacterial pathogen responsible for more than 700 million infections annually worldwide. Beta-lactam antibiotics are the primary agents used to treat GAS infections. Naturally occurring GAS clinical isolates with decreased susceptibility to beta-lactam antibiotics attributed to mutations in PBP2X have recently been documented. This prompted us to perform a genome-wide screen to identify GAS genes that alter beta-lactam susceptibility in vitro. Using saturated transposon mutagenesis, we screened for GAS gene mutations conferring altered in vitro susceptibility to penicillin G and/or ceftriaxone, two beta-lactam antibiotics commonly used to treat GAS infections. In the aggregate, we found that inactivating mutations in 150 GAS genes are associated with altered susceptibility to penicillin G and/or ceftriaxone. Many of the genes identified were previously not known to alter beta-lactam susceptibility or affect cell wall biosynthesis. Using isogenic mutant strains, we confirmed that inactivation of clpX (Clp protease ATP-binding subunit) or cppA (CppA proteinase) resulted in decreased in vitro susceptibility to penicillin G and ceftriaxone. Deletion of murA1 (UDP-N-acetylglucosamine 1-carboxyvinyltransferase) conferred increased susceptibility to ceftriaxone. Our results provide new information about the GAS genes affecting susceptibility to beta-lactam antibiotics. IMPORTANCE Beta-lactam antibiotics are the primary drugs prescribed to treat infections caused by group A streptococcus (GAS), an important human pathogen. However, the molecular mechanisms of GAS interactions with beta-lactam antibiotics are not fully understood. In this study, we performed a genome-wide mutagenesis screen to identify GAS mutations conferring altered susceptibility to beta-lactam antibiotics. In the aggregate, we discovered that mutations in 150 GAS genes were associated with altered beta-lactam susceptibility. Many identified genes were previously not known to alter beta-lactam susceptibility or affect cell wall biosynthesis. Our results provide new information about the molecular mechanisms of GAS interaction with beta-lactam antibiotics.

Influenza A Virus Exacerbates Group A Streptococcus Infection and Thwarts Anti-Bacterial Inflammatory Responses in Murine Macrophages.

Seasonal influenza epidemics pose a considerable hazard for global health. In the past decades, accumulating evidence revealed that influenza A virus (IAV) renders the host vulnerable to bacterial superinfections which in turn are a major cause for morbidity and mortality. However, whether the impact of influenza on anti-bacterial innate immunity is restricted to the vicinity of the lung or systemically extends to remote sites is underexplored. We therefore sought to investigate intranasal infection of adult C57BL/6J mice with IAV H1N1 in combination with bacteremia elicited by intravenous application of Group A Streptococcus (GAS). Co-infection in vivo was supplemented in vitro by challenging murine bone marrow derived macrophages and exploring gene expression and cytokine secretion. Our results show that viral infection of mice caused mild disease and induced the depletion of CCL2 in the periphery. Influenza preceding GAS infection promoted the occurrence of paw edemas and was accompanied by exacerbated disease scores. In vitro co-infection of macrophages led to significantly elevated expression of TLR2 and CD80 compared to bacterial mono-infection, whereas CD163 and CD206 were downregulated. The GAS-inducible upregulation of inflammatory genes, such as Nos2, as well as the secretion of TNFα and IL-1β were notably reduced or even abrogated following co-infection. Our results indicate that IAV primes an innate immune layout that is inadequately equipped for bacterial clearance.

The Bacterial Markers of Identification of Invasive CovR/CovS-Inactivated Group A Streptococcus.

ABSTRACTNecrotizing fasciitis is a severe infectious disease that results in significant mortality. Streptococcus pyogenes (group A Streptococcus, GAS) is one of the most common bacterial pathogens of monomicrobial necrotizing fasciitis. The early diagnosis of necrotizing fasciitis is crucial; however, the typical cutaneous manifestations are not always presented in patients with GAS necrotizing fasciitis, which would lead to miss- or delayed diagnosis. GAS with spontaneous inactivating mutations in the CovR/CovS two-component regulatory system is significantly associated with destructive diseases such as necrotizing fasciitis and toxic shock syndrome; however, no specific marker has been used to identify these invasive clinical isolates. This study evaluated the sensitivity and specificity of using CovR/CovS-controlled phenotypes to identify CovR/CovS-inactivated isolates. Results showed that the increase of hyaluronic acid capsule production and streptolysin O expression were not consistently presented in CovS-inactivated clinical isolates. The repression of SpeB is the phenotype with 100% sensitivity of identifying in CovS-inactivated isolates among 61 clinical isolates. Nonetheless, this phenotype failed to distinguish RopB-inactivated isolates from CovS-inactivated isolates and cannot be utilized to identify CovR-inactivated mutant and RocA (Regulator of Cov)-inactivated isolates. In this study, we identified and verified that PepO, the endopeptidase which regulates SpeB expression through degrading SpeB-inducing quorum-sensing peptide, was a bacterial marker to identify isolates with defects in the CovR/CovS pathway. These results also inform the potential strategy of developing rapid detection methods to identify invasive GAS variants during infection.IMPORTANCE Necrotizing fasciitis is rapidly progressive and life-threatening; if the initial diagnosis is delayed, deep soft tissue infection can progress to massive tissue destruction and toxic shock syndrome. Group A Streptococcus (GAS) with inactivated mutations in the CovR/CovS two-component regulatory system are related to necrotizing fasciitis and toxic shock syndrome; however, no bacterial marker is available to identify these invasive clinical isolates. Inactivation of CovR/CovS resulted in the increased expression of endopeptidase PepO. Our study showed that the upregulation of PepO mediates a decrease in SpeB-inducing peptide (SIP) in the covR mutant, indicating that CovR/CovS modulates SIP-dependent quorum-sensing activity through PepO. Importantly, the sensitivity and specificity of utilizing PepO to identify clinical isolates with defects in the CovR/CovS pathway, including its upstream RocA regulator, were 100%. Our results suggest that identification of invasive GAS by PepO may be a strategy for preventing severe manifestation or poor prognosis after GAS infection.

RARE CASE OF SEVERE NECROTIZING PNEUMONIA DUE TO STREPTOCOCCUS PYOGENES RESULTING IN REFRACTORY HYPOXEMIA

RARE CASE OF SEVERE NECROTIZING PNEUMONIA DUE TO STREPTOCOCCUS PYOGENES RESULTING IN REFRACTORY HYPOXEMIA

Reader Response: Lack of Association of Group A Streptococcal Infections and Onset of Tics: European Multicenter Tics in Children Study.

Schrag et al.1 reported that Group A streptococcal (GAS) exposure is unrelated to tics in children at risk for tic disorders. The critical limitations of this study are that only children with genetic risks for tics were studied, and information about risk for autoimmunity, infection susceptibility, and antibiotics use is absent.1 The European Multicenter Tics in Children Study (EMTICS) home page states that many patients refused to participate when told that antibiotic use would be limited. This would introduce a negative selection bias against families who perceive themselves as high risk and patients procuring antibiotics outside the trial.2 GAS infections trigger autoimmune disorders through mechanisms mediated by superantigens and adaptive immunity.3 Studies in rodent models for GAS-induced neuropsychiatric symptoms showed that Th17 lymphocytes and autoantibodies, generated in response to multiple infections, targeted the brain and triggered neuroinflammation. They also caused blood-brain barrier damage and neuronal circuitry dysfunction, which elicited behavioral abnormalities.4 We have witnessed the transformative effect of antibiotic treatment in a small group of patients with Obsessive-Compulsive Disorder (OCD) and/or movement disorders secondary to GAS infections.5 Consequently, we are concerned that results from the EMTICS study may be incorrectly extrapolated to children and adolescents with acute onset of tics, resulting in effective treatment being withheld.

Should Linezolid Replace Clindamycin as the Adjunctive Antimicrobial of Choice in Group A Streptococcal Necrotizing Soft Tissue Infection and Toxic Shock Syndrome? A Focused Debate.

Group A Streptococcus (GAS) necrotizing soft tissue infections and toxic shock syndrome remain high-mortality conditions. In vitro and animal model data, as well as multiple observational studies, suggest adjunctive clindamycin (ie, given with a beta-lactam) reduces invasive GAS infection mortality by inhibiting exotoxin production. Unfortunately, clindamycin resistance in GAS has been rapidly increasing in the United States since the mid-2010s, although the clinical significance of this remains unclear. Linezolid is a promising alternative adjunctive agent to which US GAS isolates remain near-universally susceptible, with a similar mechanism of action and similar in vitro evidence of GAS virulence factor attenuation. However, the clinical data supporting linezolid's value in severe GAS infections are far more limited. Here the authors review the data and reasoning behind a general preference for clindamycin or linezolid in a focused, pro-con debate format.

The effects of air pollutants exposure on the transmission and severity of invasive infection caused by an opportunistic pathogen Streptococcus pyogenes

Currently, urbanization is associated with an increase in air pollutants that contribute to invasive pathogen infections by altering the host's innate immunity and antimicrobial resistance capability. Streptococcus pyogenes, also known as Group A Streptococcus (GAS), is a gram-positive opportunistic pathogen that causes a wide range of diseases, especially in children and immunosuppressed individuals. Diesel exhaust particle (DEP), a significant constituent of particulate matter (PM), are considered a prominent risk factor for respiratory illness and circulatory diseases worldwide. Several clinical and epidemiological studies have identified a close association between PM and the prevalence of viral and bacterial infections. This study investigated the role of DEP exposure in increasing pulmonary and blood bacterial counts and mortality during GAS M1 strain infection in mice. Thus, we characterized the upregulation of reactive oxygen species production and disruption of tight junctions in the A549 lung epithelial cell line due to DEP exposure, leading to the upregulation of GAS adhesion and invasion. Furthermore, DEP exposure altered the leukocyte components of infiltrated cells in bronchoalveolar lavage fluid, as determined by Diff-Quik staining. The results highlighted the DEP-related macrophage dysfunction, neutrophil impairment, and imbalance in pro-inflammatory cytokine production via the toll-like receptor 4/mitogen-activated protein kinase signaling axis. Notably, the tolerance of the GAS biofilms toward potent antibiotics and bacterial resistance against environmental stresses was also significantly enhanced by DEP. This study aimed to provide a better understanding of the physiological and molecular interactions between exposure to invasive air pollutants and susceptibility to invasive GAS infections.

Distribution of emm genotypes in group A streptococcus isolates of Korean children from 2012 to 2019.

Changes in the epidemiology of group A streptococcus (GAS) infection is related to emm genotype. We studied the distribution of emm genotypes and their antibiotic susceptibility among Korean children. Isolates from children with GAS infection between 2012 and 2019 were collected. emm typing and cluster analysis was performed according to the Centers for Disease Control emm cluster classification. Antimicrobial susceptibility was tested using the E-test and resistance genes were analyzed for macrolide resistant phenotypes. Among 169 GAS isolates, 115 were from children with scarlet fever. Among invasive isolates, emm1 (6/22, 27.3%), emm12 (4/22, 18.2%), and emm4 (4/22, 18.2%) were most common. In scarlet fever, although emm4 (38/115, 33.0%) was the most prevalent throughout the study period, emm4 was replaced by emm3 (28/90, 31.1%) during an outbreak in 2017-2018. Among all isolates, only 2 (1.2%) exhibited erythromycin resistance and harbored both ermA and ermB genes. In this analysis of GAS isolated from Korean children, emm1 was the most prevalent in invasive infection. In scarlet fever, emm4 was prevalent throughout the study period, with an increase in emm3 during 2017-2018. GAS isolates during 2012-2019 demonstrated low erythromycin resistance.

Development of a lateral flow immunoassay using antibody cocktail for the detection of the various epidemic subtypes of group A Streptococcus in clinical samples

Group A Streptococcus (GAS), a major pathogen, causes various respiratory diseases with substantial morbidity and mortality worldwide. In this study, we develop an immunoassay for the early screening and diagnosis of GAS infections. A latex beads-based lateral flow immunoassay (LBs-LFIA) and a fluorescent beads-based LFIA (FBs-LFIA) using an antibody cocktail that was coated on the test line (T line), the limit of detection (LoD) of LBs-LFIA was 105 CFU mL−1 and FBs-LFIA was 103 CFU mL−1. Furthermore, the use of the antibody cocktail led to the detection of the various epidemic clinical types of GAS with high sensitivity (100%) and specificity (＞95%). To devise a point-of-care testing (POCT) platform for mass screening in low-resource areas, a mobile phone-based portable strip reader capable of visually interpreting the results was developed and the LoD of LBs-LFIA and FBs-LFIA were calculated as 104 CFU mL−1 and 102 CFU mL−1, respectively. Taken together, we suggest that the developed LBs-LFIA and FBs-LFIA using the antibody cocktail can be used for the clinical emergency detection of GAS infections.

Clindamycin but not Intravenous Immunoglobulins reduces mortality in a retrospective cohort of critically ill patients with bacteremic Group A Streptococcal infections.

ObjectivesMortality of patients requiring Intensive Care Unit (ICU) admission for an invasive group A streptococcal (GAS) infection continues being high. In critically ill patients with bacteremic GAS infection we aimed at determining risk factors for mortality.Patients and methodsRetrospective multicentre study carried out in nine ICU in Southern Spain. All adult patients admitted to the participant ICUs from January 2014 to June 2019 with one positive blood culture for S. pyogenes were included in this study. Patient characteristics, infection-related variables, therapeutic interventions, failure of organs, and outcomes were registered. Risk factors independently associated with ICU and in-hospital mortalities were determined by multivariate regression analyses.ResultsFifty-seven patients were included: median age was 63 (45-73) years, median SOFA score at admission was 11 (7-13). The most frequent source was skin and soft tissue infection (n=32) followed by unknown origin of bacteremia (n=12). In the multivariate analysis, age (OR 1.079; 95% CI 1.016-1.145), SOFA score (OR 2.129; 95% CI 1.339-3.383) were the risk factors for ICU mortality and the use of clindamycin was identified as a protective factor (OR 0.049; 95% CI 0.003-0.737). Age and SOFA were the independent factors associated with hospital mortality however the use of clindamycin showed a strong trend but without reaching statistical significance (OR 0.085; 95% CI 0.007-1.095).ConclusionIn this cohort of critically ill patients the use of intravenous immunoglobulin was not identified as a protective factor for ICU or hospital mortality treatment with clindamycin significantly reduced mortality after controlling for confounders.

Prevalence and identification of antibiotic-resistant scarlet fever group A Streptococcus strains in some paediatric cases at Shenzhen, China

This study aimed to investigate the annual incidence, molecular epidemiological characteristics, and antimicrobial resistance of group A Streptococcus (GAS) clinical isolates from paediatric patients at Shenzhen Children's Hospital during 2016-2020. Clinical samples were collected from paediatric patients with a suspected diagnosis of GAS infections. We studied the annual incidence and characteristics of GAS infections using the GAS antigen detection method. Additionally, 250 GAS isolates were randomly selected for genotyping of the emm gene, and antimicrobial susceptibility assay was performed using the Kirby-Bauer paper dispersion strategy. Among 43 593 collected samples, 9313 were positive for the GAS antigen. The main emm type was emm12, followed by emm1, emm6, and emm 4, which were used for distinguishing 90% of the scarlet fever isolated strains. The percentage of emm1 increased from 36% in 2016 to 44% in 2019, whereas the percentage of emm12 decreased from 62% to 50%. Several unusual emm types isolated from scarlet fever patients showed an increase in proportions from 2016 to 2020. These GAS isolates were sensitive to penicillin, ceftriaxone, and vancomycin and were highly resistant to erythromycin and clindamycin. There was a high incidence of GAS infections during 2016-2020 in Shenzhen, China. The GAS isolates had a high resistance rate to erythromycin and clindamycin; penicillin was the antibiotic of choice for GAS infections. The common emm types were emm12 and emm1. Future studies should investigate the clonal structure and superantigen profiles of the population of GAS isolates associated with scarlet fever.