Outcomes of Pregnancy with Group B Streptococcal Infections in Najran, Saudi Arabia

Background: The gram-positive, beta-hemolytic, and chain-forming Group B Streptococcus (GBS), commonly known as Streptococcus agalactiae, may asymptomatically invade the human gastrointestinal and vaginal tracts. However, GBS may become very invasive and pathogenic to the mother and baby during pregnancy, having negative effects. Study Aim: This study aims to investigate the pregnancy outcomes of women who tested positive for genitourinary GBS infection during pregnancy in Najran, Saudi Arabia. Methods: Data was collected retrospectively from patient files in Armed Forces Hospital, Najran, Saudi Arabia. Data collected were entered to a Microsoft Excel sheet, then imported and analysed using the Statistical Package for Social Sciences. Results: The study included 272 women of whom 66.5% were 31 to 45 years old. Gestational diabetes was diagnosed in 8.5% of the sample, 71.7% had a normal spontaneous vaginal delivery (NSVD), 1.8% had previous abortions, and 27.2% of new-borns were admitted to the NICU after delivery. There was a significant association between NICU admissions and women employment status (p = 0.001), gravidity (p = 0.001), parity (p = 0.001), history of abortions (p = 0.001), medical conditions (p = 0.049), and mode of delivery (p = 0.049). Conclusion: According to the findings of our study, GBS infection during pregnancy is associated to more NICU admissions. NICU admissions were significantly correlated with gestational diabetes, hypertension, and hypothyroidism in mothers but not with intrapartum antibiotic use.

Invasive group B streptococcal infection in a patient with post splenectomy for hypersplenism secondary to liver cirrhosis and portal hypertension

BACKGROUND:Splenectomy in patients with liver cirrhosis(LC)is expected to become more common owing to its efficacy on portal hemodynamics.In this report we describe an alarming case of group B streptococcus(GBS)infection after splenectomy in a patient with LC.METHODS:A 72-year-old woman with a history of LC was admitted to our emergency department because of respiratory failure.The patient had received left lateral segmentectomy of the liver and splenectomy three months before admission.Pulmonary examination revealed significant wheezing during inspiration and expiration,but no crackles and stridor.Chest radiography and CT showed no infiltrates.A presumptive diagnosis of bronchial asthma caused by upper respiratory infection was made.Four days after admission,GBS infection was confirmed by blood culture and penicillin G was administered.Antibiotics were given intravenously for a total of 12 days.RESULTS:The patient was discharged on the 12th day after admission.CONCLUSIONS:Although efficacy of splenectomy in patients with LC has been reported,immune status should be evaluated for a longer period.Patients who have undergone splenectomy are highly susceptible to bacteria;moreover,LC itself is an independent risk factor for mortality in patients with sepsis.Since prophylaxis against GBS has not been established,immediate action should be taken.Emergency physicians should be aware of invasive GBS infection in the context of the critical risk factors related to splenectomy and LC,particularly the expected increase of splenectomy performed in LC patients.

Group A streptococcal antigen exposed rat model to investigate neurobehavioral and cardiac complications associated with post-streptococcal autoimmune sequelae

Background:The neuropsychiatric disorders due to post-streptococcal autoimmune complications such as Sydenham's chorea(SC)are associated with acute rheumatic fever and rheumatic heart disease(ARF/RHD).An animal model that exhibits char-acteristics of both cardiac and neurobehavioral defects in ARF/RHD would be an important adjunct for future studies.Since age,gender,strain differences,and geno-types impact on the development of autoimmunity,we investigated the behavior of male and female Wistar and Lewis rat strains in two age cohorts(6 weeks and 12 weeks)under normal husbandry conditions and following exposure to group A streptococcus(GAS).Methods:Standard behavioral assessments were performed to determine the impair-ments in fine motor control(food manipulation test),gait and balance(beam walk-ing test),and obsessive-compulsive behavior(grooming and marble burying tests).Furthermore,electrocardiography,histology,and behavioral assessments were per-formed on male and female Lewis rats injected with GAS antigens.Results:For control Lewis rats there were no significant age and gender dependent differences in marble burying,food manipulation,beam walking and grooming be-haviors.In contrast significant age-dependent differences were observed in Wistar rats in all the behavioral tests except for food manipulation.Therefore,Lewis rats were selected for further experiments to determine the effect of GAS.After ex-posure to GAS,Lewis rats demonstrated neurobehavioral abnormalities and cardiac pathology akin to SC and ARF/RHD,respectively.Conclusion:We have characterised a new model that provides longitudinal stability of age-dependent behavior,to simultaneously investigate both neurobehavioral and cardiac abnormalities associated with post-streptococcal complications.

Streptococcal toxic shock syndrome after hemorrhoidectomy: A case report

BACKGROUND Streptococcal toxic-shock syndrome after hemorrhoidectomy is rare but may be catastrophic.Group A streptococci have produced various surface proteins and exotoxins due to genetic changes to fight the human body’s immune response.Though life threatening infection after hemorrhoidectomy rarely occurs,all surgeons should be aware of the potential complications of severe sepsis after hemorrhoidectomy and keep in mind their clinical presenting features in order to diagnose early and administer appropriate and effective therapeutic drugs early.CASE SUMMARY Here,we present a case of a 56-year-old man with a painful thrombotic external hemorrhoid who presented to our outpatient department for management.There was no history of systemic diseases or recent disease infection.Hemorrhoidectomy was suggested and performed.After surgery,the patient developed hypotension,tachycardia,fever with chills and renal function impairment on day 2 post-operation.The clinical condition progressed to severe septic shock and metabolic acidosis.The patient responded poorly to treatment and expired after 1 d even with use of extracorporeal membrane oxygenation.The results of the blood and wound cultures showed group A streptococcus pyogenes.CONCLUSION Although extremely uncommon,all surgeons should be aware of these potential life-threatening septic complications and alert to the presenting features for patients receiving hemorrhoidectomy.

Streptococcal Pyrogenic Exotoxin Genes SpeA and SpeB in Isolates of Streptococcus pyogenes from Children with Pharyngitis, Gezira State, Sudan

Background: Streptococcus pyogenes (group A streptococcus, GAS) is an important human bacterial pathogen. This organism possesses many virulence factors, Streptococcal pyrogenic exotoxinone of these. Aim: Detection of Streptococcal pyrogenic exotoxin SpeA and SpeB in isolated Streptococcus pyogenes. Methods: Tow hundred throat swab samples were collected from children with pharyngitis referred to Pediatric Teaching hospital and ENT hospital Wad medani, Sudan, from January to November 2021. The questionnaire was filled out to collect clinical and demographic data. Throat swabs were collected and processed with the standard microbiological procedure to isolate Streptococcus pyogenes. Antimicrobial susceptibility testing was done on all GAS isolates using the Kirby Bauer disk diffusion method according to clinical laboratory standard institute (CLSI) guidelines. Detection of Spy 1258 gene and Streptococcal pyrogenic exotoxins SpeA and SpeB were done by using Multiplex PCR. Results: Amongst the Tow hundred collected samples fifty-one isolates (25.5%) were identified as S. pyogenes. Antibiotic susceptibility testing showed that all the GAS isolates were sensitive to Azithromycin and Penicillin. Sensitivity to Erythromycin, Gentamicin, Clarithromycin, Amoxicillin and Cephalexin were 88.2%, 86.3%, 45.1%, 41.2%, 13.7%, respectively. SpeA was detected in 17 (33.3%) and SpeB in 48 (94.1%). Conclusion: Streptococcal pyrogenic exotoxin genes SpeA and SpeB were detected in 17 (33.3%) and 48 (94.1%) respectively of Streptococcus pyogenes isolates.

Identification of the Bacterial Gene in Patients Who Repeatedly Develop Streptococcal Pharyngitis

Background: We aimed at determining whether the pathogenic bacteria at the onset of disease are genetically different and whether this affects future choice of the therapeutic methods against group A β-hemolytic streptococcal acute pharyngitis/tonsillitis. Methods: A pharynx swab was collected from pediatric patients who visited our hospital. The swab was cultured, and hemolytic streptococcus was detected 230 times. We isolated pathogenic bacteria of patients infected more than once and examined the bacteria using pulse-field gel electrophoresis. Results: Based on gene search results, we found that if the period of developing relapse was within 1 month from the first infection, all patients had the same gene. However, all patients in whom reinfection occurred after 6 months or later had different pertinent genes. Conclusions: The number of relapse/reinfection is significant for this disease, and considerably caution is essential for its treatment. No changes to antibacterial drug administration may be necessary for the second administration unless more than 6 months have passed since the first infection.

Hypothesizing That Pediatric Autoimmune Neuropsychiatric Associated Streptococcal (PANDAS) Causes Rapid Onset of Reward Deficiency Syndrome (RDS) Behaviors and May Require Induction of “Dopamine Homeostasis”

Pediatric autoimmune neuropsychiatric disorders associated with group A streptococcal infections (PANDAS) is a concept that is used to characterize a subset of children with neuropsychiatric symptoms, tic disorders, or obsessive-compulsive disorder (OCD), whose symptoms are exacerbated by group A streptococcal (GAS) infection. PANDAS has been known to cause a sudden onset of reward deficiency syndrome (RDS). RDS includes multiple disorders that are characterized by dopaminergic signaling dysfunction in the brain reward cascade (BRC), which may result in addiction, depression, avoidant behaviors, anxiety, tic disorders, and/or OCD. According to research by Blum et al., the dopamine receptor D2 (DRD2) gene polymorphisms are important prevalent genetic determinants of RDS. The literature demonstrates that infections like Borrelia and Lyme, as well as other infections like group A beta-hemolytic streptococcal (GABHS), can cause an autoimmune reaction and associated antibodies target dopaminergic loci in the mesolimbic region of the brain, which interferes with brain function and potentially causes RDS-like symptoms/behaviors. The treatment of PANDAS remains controversial, especially since there have been limited efficacy studies to date. We propose an innovative potential treatment for PANDAS based on previous clinical trials using a pro-dopamine regulator known as KB220 variants. Our ongoing research suggests that achieving “dopamine homeostasis” by precision-guided DNA testing and pro-dopamine modulation could result in improved therapeutic outcomes.

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.

The role of myeloid cells in prevention and control of group A streptococcal infections

Group A Streptococcus(GAS;Streptococcus pyogenes)is one of the most versatile bacteria among human pathogens.Non-invasive GAS infections can cause common diseases,such as pharyngitis and impetigo.Severe invasive GAS infections can lead to rapid progressive and life-threatening manifestations,including necrotizing fasciitis and streptococcal toxic shock syndrome with high mortality rates ranging from 30%to 70%.Therefore,GAS is also known as"killer microbes"or"flesh-eating bacteria".During severe invasive GAS infections,anti-bacterial immunity is impeded by attenuation of the cellular components of innate immune responses.However,this loss of protection is compensated for by interferon-γ-producing immature myeloid cells,which are recruited upon severe invasive GAS infections in mouse models.In this review,we discuss and summarize the current knowledge on the role of interferon-γ-producing myeloid cells and other myeloid cells in the prevention and control of severe invasive GAS infections.

Perianal infectious dermatitis: An underdiagnosed, unremitting and stubborn condition

Perianal infectious dermatitis(PID) represents a super-ficial inflammation of the perianal skin, which is of bac-terial origin(classically, group A beta-hemolytic strepto-cocci). This narrative review aims to critically review and summarize the available scientific literature regarding pediatric PID, being the first of its kind, to the best of the author's knowledge. It also reports the first cases of Romanian children with PID. Multiple databases were subjected to systematic literature search(from 1966 to April 30, 2018) to identify studies and case reports of children with PID. As such, this review provides up-dated information about essential aspects of PID(epi-demiology, etiology, pathogenesis, as well as clinical features, required investigations and therapeutic options) and of diagnostic pitfalls. Although a well-defined entity, PID remains largely underdiagnosed. PID may mimic other common conditions with skin manifestations(like candidiasis, pinworms, eczema, irritant dermatitis, anal fissure, hemorrhoids, Crohn's disease, psoriasis, sebor-rheic dermatitis, zinc deficiency dermatosis and even sexual abuse), with consequent unnecessary, sometimes expensive and invasive investigations and futile therapies, which cause patients and families discomfort and distress. Since PID has an unremitting course, early recognition is imperative, as it allows for prompt and efficacious antibiotic therapy. However, PID represents a stubborn condition and, even if properly treated, its recurrence rate remains high. Further well-designed prospective randomized controlled trials, with adequate follow-up, are required in order to formulate the optimum personalized antibiotic therapy(oral alone or in association with topical medication), able to prevent recurrences. Awareness of this condition by healthcare professionals should improve patient outcomes.

OK-432 INHIBITED B16 MELANOMA GROWTH AND INDUCED A TH1 DOMINANT STATE IN TUMOR BEARING MOUSE

Objective: To investigate the antitumor mechanisms of the streptococcal preparation OK-432. Methods: Using C57BL/6 mouse bearing B16 melanoma, we observed the antitumor activity of OK-432 and investigated the effect of OK-432 on multi-cytokine (IL-2, IL-4, IL-6, IL-10, IL-12, IFN-g) production of mouse splenocyte both in vitro and in vivo. Results: As compared with control, OK-432 significantly inhibited B16 melanoma growth and lengthened mice survival time (P<0.05). In vitro OK-432 could stimulate splenocyte from tumor bearing mice to secrete IL-6, IL-12, IFN-g and IL-10 remarkably (P<0.01). In vivo OK-432 led to the increased production of IL-2, IL-12 and IFN-g but decreased production of IL-10 (P<0.05). When the splenocytes harvested from OK-432 treated mice were stimulated with OK-432 again in vitro, the production of IFN-g increased and IL-10 decreased significantly (P<0.05). Conclusion: OK-432 could boost multiple cytokines production, especially IL-12 which skewed T cells in a Th1 dominant state and enhanced the host antitumor activities.

Characterization of NADase-Inactive NAD⁺Glycohydrolase in <i>Streptococcus pyogenes</i>

Background: Streptococcus pyogenes secretes NAD+ glycohydrolase (NADase, also known as SPN or Nga). All S. pyogenes strains examined to date possess the gene that encodes SPN (spn), but some strains produce SPN that lacks detectable NADase activity. Although there is much evidence to support that SPN’s NADase activity contributes to virulence, there is very little evidence that NADase-inactive SPN has detectable functions. Results: In order to characterize the NADase-inactive SPN, we firstly attempted to clone the NADase-inactive spn allele in Escherichia coli. Although we obtained recombinants which were shown to have the correct size insert, all had some mutations in the spn allele. Therefore, we attempted to change the mutated nucleotides back to the original nucleotides. While a nucleotide mutagenesis (inverse PCR method) easily changed a target nucleotide of control genes back to the original nucleotides, the mutations of NADase-inactive spn allele were never successfully converted back to the original nucleotides. Finally the mutant spn alleles were sub-cloned into another vector (pLZ12-Km2), which is maintained in both E. coli and S. pyogenes. The resultant plasmids were subjected to nucleotide mutagenesis using inverse PCR;the resultant mutagenized plasmid DNAs were used to transform both E. coli and S. pyogenes strains. We observed successful nucleotide substitutions back to the original spn nucleotide sequence in S. pyogenes transformants, but not in E. coli transformants. Thus, the NADase-inactive spn allele was successfully cloned in S. pyogenes, but not in E. coli. However, we could not find an association with NADase-inactive spn allele and virulence in a mouse infection model. Conclusions: These results suggest that NADase-inactive spn allele has some toxic effect to E. coli, but not S. pyogenes. This effect may due to an as of yet unknown function attributable to NADase-inactive SPN.

Streptococcus agalactiae:Sensitivity profile in pregnant women attending health units in northeastern Brazil

BACKGROUNDG roup B Streptococcus agalactiae (GBS) is the main etiologic agent associated withearly-onset neonatal sepsis, and of all newborns of parturients colonized by GBS,approximately 1%-2% develop invasive, early-onset disease. The risk of infectionincreases to 15.2% in premature neonates, to 10.7% when the parturient haschorioamnionitis or premature rupture of membranes for more than 24 h and to9.7% if the mother has postpartum bacteremia. In addition to causing perinatal,neonatal and postnatal deaths, neonatal hospital infection is associated with highcosts, as hospitalization is three times longer than in uninfected children. Theidentification of pregnant women colonized by GBS, through universal screening,associated with the adoption of appropriate antibiotics at the time of delivery arethe most successful preventive measures.AIMTo evaluate the sensitivity profile of GBS isolated from pregnant womenattending Vitória da Conquista-BA.METHODS This is a cross-sectional study with a quantitative approach carried out in themunicipality of Vitória da Conquista-Bahia between February 2017 and March2018. The study population was composed of 210 pregnant women, with agestational age of 32 to 40 wk, who were aged 18 years or older living in the urbanarea of the municipality of Vitória da Conquista. After a brief explanation aboutthe research and obtaining a signed an informed consent form, data andvaginorectal swabs were collected from the women for GBS research. Examinationof the samples in order to identify the presence of GBS was by culture on sheep blood agar and chromogenic agar for GBS and then, seeded on plates containingstreptococcal culture medium and incubated for 18 h to 24 h at 35°C. Theantimicrobial sensitivity profile of positive GBS samples was determined by thedisk diffusion technique, according to the Clinical and Laboratory StandardsInstitute manual (2017). The data obtained were stored in a database usingMicrosoft Office Excel spreadsheets and a descriptive analysis was performedwith the aid of the EPI-INFO statistical package (version 3.5.2).RESULTSAmong the 210 pregnant women participating in the study, 38 (18.1%) had apositive GBS culture. All strains isolated from GBS were sensitive to 10 Upenicillin, 10 μg ampicillin, 30 μg cefotaxime and 30 μg vancomycin. Seven strains(18.4%) resistant to clindamycin 2 μg and eight (21.1%) resistant to erythromycin15 μg were found. Of these, six were concomitantly resistant to erythromycin andclindamycin, two resistant only to erythromycin and one resistant only toclindamycin. All nine GBS isolates that showed resistance to erythromycin and/orclindamycin showed negative results on the D-test. Two thirds of the isolatesshowed cMLSB phenotype and resistance only to erythromycin in specimens inthis study (02), refers to strains with phenotype M and resistance to clindamycin(01) only with phenotype L.CONCLUSIONChemoprophylaxis for GBS in pregnant women, especially for those allergic topenicillin, should be guided by an antimicrobial susceptibility test as resistantGBS strains were reported in this study.

Tonsillitis in children: unnecessary laboratory studies and antibiotic use

Background:The Finnish Current Care Guidelines on diagnostics and treatment of sore throat recommend the treatment of only group A streptococcus(GAS)positive cases with penicillin.The aim of the study was to evaluate how these guidelines are followed in the pediatric emergency unit.Methods:We analyzed retrospectively the data on microbiological studies and blood tests done,and data on prescribing of antibiotics,of 200 children admitted for febrile exudative tonsillitis.Results:After the clinical diagnosis of exudative tonsillitis,antigen test and/or culture for GAS identifi cation was done in>95%of cases.All the 32(16%)children with GAS infection,but also 52(38%)of the 137 children without any evidence of bacterial infection received antibiotics.Additional laboratory studies were done in 96%of children.Serum C-reactive concentrations or white blood cell counts were not able to separate streptococcal from non-streptococcal tonsillitis.No serious bacterial infection was diagnosed.Conclusions:The Finnish Current Care Guidelines lead to over-treatment with antibiotics.None of the 200 children returned after discharge,suggesting that undertreatment did not happen.

A novel colloidal gold immunochromatography assay strip for the diagnosis of schistosomiasis japonica in domestic animals

Background:Schistosomiasis remains a major public health concern in China and an epidemiological survey has revealed that schistosome-infected bovines and goats are the main transmission sources for the disease.Therefore,development of a sensitive technique for the diagnosis of schistosomiasis in domestic animals is necessary.Method:A novel colloidal gold immunochromatography assay(GICA)strip was developed for detecting Schistosoma japonicum in domestic animals.The colloidal gold was conjugated with recombinant streptococcal protein G(rSPG).As the test and control lines,the schistosome soluble egg antigen and rSPG,respectively,were blotted on nitrocellulose membrane.Results:The lowest detectable serum dilution was 1∶640 for schistosome-infected buffaloes.The cross-reaction rate of GICA was 14.29%with Paramphistomum sp.in buffaloes,16.67%with Haemonchus sp.in goats,and 33.33%with Orientobilharzia sp.in goats.These results were slightly lower and similar to those obtained through ELISA.Moreover,the strips for detecting S.japonicum in mice,rabbits,buffaloes,and goats showed high sensitivity(100.00%,100.00%,100.00%,and 100.00%,respectively)and specificity(100.00%,100.00%,94.23%,and 88.64%,respectively).And the sensitivity or specificity of the GICA strips did not present any significant differences after storage for 12 months at room temperature.When compared with ELISA,the GICA strips exhibited similar sensitivity and specificity in the diagnosis of schistosomiasis in mice,rabbits,buffaloes,and goats.Besides,only 5μl of serum are required for the test and the detection can be completed within 5 min.Conclusion:This study is the first to develop a GICA strip using gold-rSPG conjugate for the diagnosing of schistosomiasis in domestic animals,and preliminary results showed that the developed strip may be suitable for large-scale screening of schistosomiasis in endemic areas.

Erythema nodosum

Background Erythema nodosum can be associated with a number of systemic diseases. There is, however, a paucity of information in the pediatric literature on this condition. The purpose of this article is to familiarize pediatricians with the evaluation, diagnosis, and treatment of erythema nodosum. Data sources A PubMed search was completed in Clinical Queries using the key terms 'erythema nodosum'. Results Clinically, erythema nodosum presents with a sudden onset of painful, erythematous, subcutaneous nodules mainly localized to the pretibial areas. Lesions are usually bilateral and symmetrical, ranging from 1 to 5 cm in diameter. Erythema nodosum may be associated with a variety of conditions such as infection, medications, sarcoidosis, pregnancy, inflamma-tory bowel disease, vaccination, autoimmune disease, malignancy, and miscellaneous causes. The condition is idiopathic in approximately 50% of cases. The diagnosis is mainly clinical with biopsy reserved for atypical cases. To evaluate for the underlying cause, some basic laboratory screening studies are worthwhile in most cases and include a complete blood cell count, erythrocyte sedimentation rate and/or C-reactive protein, throat swab culture, antistreptococcal O titers, and a chest radiograph. Other tests should be individualized, guided by the history and physical examination results. Most cases of ery-thema nodosum are self-limited and require no treatment. Bed rest and leg elevation are generally recommended to reduce the discomfort. Nonsteroidal anti-inflammatory drugs are the first-line treatment for pain management. Conclusions As erythema nodosum is often a cutaneous manifestation of a systemic disease, a thorough search should be performed to reveal the underlying cause.

Prevention of Perinatal Group B Streptococcus Infections

Group B streptococcus(GBS)is a leading cause of neonatal infection.Maternal vaginal-rectal colonization with GBS during the intrapartum period is a prerequisite for GBS early-onset disease(EOD).The obstetric measures for effective prevention of GBS EOD include universal prenatal screening by vaginal-rectal culture,correct specimen collection and processing,appropriate implementation of intrapartum antibiotic prophylaxis,and coordination with pediatric care providers.It is now recommended to universal screen GBS between 36^(0/7)and 37^(6/7)weeks of gestation and to identify groups of women who are eligible for intravenous intrapartum antibiotic prophylaxis as a means of preventing GBS EOD.

Genetic Characterization of Streptococcus pyogenes emm89 Strains Isolated in Japan From 2011 to 2019

Invasive infection caused by Streptococcus pyogenes emm89 strains has been increasing in several countries linked to a recently emergent clade of emm89 strains,designated clade 3.In Japan,the features of emm89 S.pyogenes strains,such as clade classification,remains unknown.In this study,we collected emm89 strains isolated from both streptococcal toxic shock syndrome(STSS)(89 STSS isolates)and noninvasive infections(72 non-STSS isolates)in Japan from 2011 to 2019,and conducted wholegenome sequencing and comparative analysis,which resulted in classification of a large majority into clade 3 regardless of disease severity.In addition,invasive disease-associated factors were found among emm89 strains,including mutations of control of virulence sensor,and absence of the hylP1 gene encoding hyaluronidase.These findings provide new insights into genetic features of emm89 strains.