Invasive group A streptococcus infections

Long-term outcomes of patients with toxic shock syndrome: A matched cohort study

OBJECTIVES

We examined long-term outcomes of toxic shock syndrome.

METHODS

We conducted a matched cohort study of 630 patients with toxic shock syndrome and 5009 healthy controls between 2006 and 2021 in Quebec, Canada. Outcomes included hospitalization for renal, cardiovascular, hepatic, and other morbidity during 15 years of follow-up. We estimated adjusted hazard ratios (HR) and 95% confidence intervals (CI) for the risk of these outcomes over time, comparing patients with toxic shock syndrome relative to matched controls.

RESULTS

Compared with healthy controls, rehospitalization rates at 15 years were higher for men with toxic shock syndrome (52.0 vs 30.0 per 100) but not for women (38.7 vs 45.6 per 100). In men, toxic shock syndrome was associated with an elevated risk of renal (HR 17.43, 95% CI 6.35-47.82), cardiovascular (HR 2.57; 95% CI 1.52-4.34), and hepatic hospitalization (HR 19.83, 95% CI 4.72-83.34). In women, toxic shock syndrome was associated with renal hospitalization (HR 4.71, 95% CI 1.94-11.45). Streptococcal toxic shock was associated with a greater risk of rehospitalization than staphylococcal toxic shock.

CONCLUSIONS

Toxic shock syndrome is associated with rehospitalization up to 15 years later, especially in men. These patients may benefit from continued follow-up to prevent long-term morbidity.

Rising clindamycin resistance in group A Streptococcus in an Irish healthcare institution

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.

Outbreak of Streptococcus pyogenes emm89 ST646 in a head and neck surgical oncology ward

Streptococcus pyogenes causes a variety of human infections, and hospital outbreaks with this pathogen have also been reported. The purpose of this study is to describe the clinical characteristics of an outbreak of S. pyogenes involving 15 patients and four healthcare workers (HCWs), as well as the molecular characteristics of the causative isolates. The course and response to the outbreak were reviewed, and information on the characteristics of the patients was extracted retrospectively from the medical records. Whole-genome sequencing of the 16 causative isolates (14 from patients and two from HCWs) was also performed. All 15 patients were postoperative of head and neck cancer with tracheotomy, and 12 had invasive infections, primarily surgical site infections, all of which resolved without causing serious illness. All but the first case was detected more than 7 days after admission. S. pyogenes was detected in two patients after empiric antimicrobial administration was performed on all inpatients and HCWs, and the outbreak was finally contained in approximately 2 months. All isolates detected in patients and HCWs belonged to emm89/clade 3, a hypervirulent clone that has emerged worldwide and was classified as sequence type 646. These isolates had single nucleotide polymorphism (SNP) differences of zero to one, indicating clonal transmission. This study demonstrated an outbreak of S. pyogenes emm89/clade 3 in a ward of patients with head and neck cancer. The global emergence of hypervirulent isolates may increase the risk of outbreaks among high-risk patients.

IMPORTANCE

This study describes an outbreak of Streptococcus pyogenes that occurred in a ward caring for patients with head and neck cancer and tracheostomies. Many cases of invasive infections occurred in a short period, and extensive empiric antimicrobial administration on patients and healthcare workers was performed to control the outbreak. Whole-genome sequencing analysis of the causative strains confirmed that it was a monoclonal transmission of strains belonging to emm89/clade 3. The epidemiology and clinical characteristics of S. pyogenes infections have changed with the replacement of the prevalent clones worldwide. In the 1980s, there was a reemergence of S. pyogenes infections in high-income countries due to the spread of hypervirulent emm1 strains. emm89/clade 3 has recently been spreading worldwide and shares common features with emm1, including increased production of two toxins, NADase, and streptolysin O. The outbreak reported here may reflect the high spreading potential and virulence of emm89/clade 3.

Epidemiological shifts in and impact of COVID-19 on streptococcal toxic shock syndrome in Japan: A genotypic analysis of group A Streptococcus isolates

OBJECTIVES

Streptococcal toxic shock syndrome (STSS) is caused by group A Streptococcus (GAS; Streptococcus pyogenes) strains. In Japan, the number of STSS cases has decreased; however, the underlying reason remains unclear. Moreover, information on distribution and prevalence of specific emm types in STSS cases is scarce. Hence, we investigated the reason for the decreased number of STSS cases in Japan.

METHODS

We genotyped emm of 526 GAS isolates obtained from 526 patients with STSS between 2019 and 2022. The distributions of emm types in each year were compared.

RESULTS

The emm1 type was predominant, with the highest proportion in 2019, which decreased after 2020 following the onset of the coronavirus disease 2019 (COVID-19) pandemic. Strains isolated during the pandemic correlated with strains associated with skin infection, whereas those isolated during the prepandemic period correlated with strains associated with both throat and skin infections. The decrease in the annual number of STSS cases during the COVID-19 pandemic could be due to a decreased proportion of strains associated with pharyngeal infections.

CONCLUSIONS

Potential associations between pandemic and STSS numbers with respect to public health measures, such as wearing masks and changes in healthcare-seeking behavior, may have affected the number of GAS-induced infections.

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

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

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

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

Invasive group A streptococcal infections requiring admission to ICU: a nationwide, multicenter, retrospective study (ISTRE study)

BACKGROUND

Group A Streptococcus is responsible for severe and potentially lethal invasive conditions requiring intensive care unit (ICU) admission, such as streptococcal toxic shock-like syndrome (STSS). A rebound of invasive group A streptococcal (iGAS) infection after COVID-19-associated barrier measures has been observed in children. Several intensivists of French adult ICUs have reported similar bedside impressions without objective data. We aimed to compare the incidence of iGAS infection before and after the COVID-19 pandemic, describe iGAS patients' characteristics, and determine ICU mortality associated factors.

METHODS

We performed a retrospective multicenter cohort study in 37 French ICUs, including all patients admitted for iGAS infections for two periods: two years before period (October 2018 to March 2019 and October 2019 to March 2020) and a one-year after period (October 2022 to March 2023) COVID-19 pandemic. iGAS infection was defined by Group A Streptococcus isolation from a normally sterile site. iGAS infections were identified using the International Classification of Diseases and confirmed with each center's microbiology laboratory databases. The incidence of iGAS infections was expressed in case rate.

RESULTS

Two hundred and twenty-two patients were admitted to ICU for iGAS infections: 73 before and 149 after COVID-19 pandemic. Their case rate during the period before and after COVID-19 pandemic was 205 and 949/100,000 ICU admissions, respectively (p < 0.001), with more frequent STSS after the COVID-19 pandemic (61% vs. 45%, p = 0.015). iGAS patients (n = 222) had a median SOFA score of 8 (5-13), invasive mechanical ventilation and norepinephrine in 61% and 74% of patients. ICU mortality in iGAS patients was 19% (14% before and 22% after COVID-19 pandemic; p = 0.135). In multivariate analysis, invasive mechanical ventilation (OR = 6.08 (1.71-21.60), p = 0.005), STSS (OR = 5.75 (1.71-19.22), p = 0.005), acute kidney injury (OR = 4.85 (1.05-22.42), p = 0.043), immunosuppression (OR = 4.02 (1.03-15.59), p = 0.044), and diabetes (OR = 3.92 (1.42-10.79), p = 0.008) were significantly associated with ICU mortality.

CONCLUSION

The incidence of iGAS infections requiring ICU admission increased by 4 to 5 after the COVID-19 pandemic. After the COVID-19 pandemic, the rate of STSS was higher, with no significant increase in ICU mortality rate.

Toxic Shock Syndrome: Eighteen Years of Experience in a Pediatric Intensive Care Unit

Introduction Toxic shock syndrome (TSS) is a life-threatening disease usually caused by a Staphylococcus aureus or group Aβ-hemolytic Streptococcus infection. Methods In this retrospective study, we included patients with TSS admitted to a tertiary hospital's pediatric intensive care unit (PICU) over the last 18 years. We compared the staphylococcal TSS (Staph-TSS) and streptococcal TSS (Strep-TSS) groups. Results We included 17 patients (64.7% male), with a median age of 6.1 years (3.0 years for streptococcal TSS versus 13.3 years for staphylococcal TSS, p = 0.040), a median of 3.0 days from symptom onset to diagnosis, and a median of 6.0 days of hospitalization. Ten patients met the Centers for Disease Control and Prevention (CDC) criteria for staphylococcal TSS (one menstrual-related) and seven met the criteria for streptococcal TSS (four of them occurring since the COVID-19 pandemic was declared). Fifteen patients had identified risk factors, primarily cutaneous lesions (29.4%). In 15 patients, at least three organs or systems were affected, with fever, rash, and hypotension as universal findings. Mucous membrane hyperemia was present in 16 patients, gastrointestinal symptoms in 14 patients, and desquamation in nine. Muscular involvement was present in seven patients, all with staphylococcal TSS (p = 0.010). All patients received two or more antibiotics, including a protein synthesis inhibitor (except for one), and required fluid resuscitation and vasoactive amines (median three days). Six patients needed invasive mechanical ventilation (median seven days). Albumin infusion was necessary in six patients, significantly more frequently in patients with streptococcal TSS (p = 0.035). Two patients with staphylococcal TSS died, while the seven patients with streptococcal TSS survived hospital discharge. There were no recurrent cases. Conclusions Our study revealed TSS severity and multiorgan involvement, emphasizing the importance of early diagnosis and intervention. Risk factors were prevalent, and we noted an increased frequency of group A streptococcal (GAS) TSS post-COVID-19 pandemic.

Effectiveness of intravenous immunoglobulin therapy for invasive group A Streptococcus infection: A Japanese nationwide observational study

OBJECTIVES

Invasive group A Streptococcus infection (iGAS) is a rare but fatal condition. We aimed to evaluate the effectiveness of intravenous immunoglobulin (IVIG) in the treatment of iGAS.

METHODS

Patients' data were extracted from a Japanese nationwide database between April 2018 and March 2021. The primary outcome was in-hospital mortality rate, whereas the secondary outcomes were 30-day and 7-day mortality rates.

RESULTS

Overall, 481 patients (median age, 65 years; female, 49.7%) were included in the analysis. The overall mortality rate was 31.0%. After adjusting for background factors, we found that IVIG treatment had no effect on in-hospital mortality (adjusted odds ratio [OR]: 0.99, 95% confidence interval [CI]: 0.93-1.04, P = 0.92). Similar results were obtained after propensity score matching (OR: 1.00, 95% CI: 0.62-1.61, P >0.99). The 7-day and 30-day mortality rates were not associated with IVIG treatment.

CONCLUSION

IVIG administration had no survival benefit in iGAS patients. However, these overall findings should not be extrapolated to streptococcal toxic shock syndrome as the effect of IVIG therapy in this condition remains uncertain. Considering the rarity of iGAS, conducting a randomized controlled trial may be impractical. Therefore, an equivalent or more extensive observational study is warranted to validate these findings.

The performance of clinical risk scores in the diagnosis of necrotising fasciitis

OBJECTIVE

Necrotising fasciitis (NF) is a quickly progressing and potentially life-threatening infection, involving the fascia and subcutaneous tissues. The diagnosis of this disease is challenging, especially due to a lack of specific clinical signs. In order to ensure a better and quicker identification of NF patients, a laboratory risk indicator score has been developed for NF (LRINEC). A variant has widened this score by adding clinical parameters (modified LRINEC). This study shows current outcomes of NF and compares the two scoring systems.

METHODS

This study was conducted between 2011 and 2018, and included patient demographics, clinical presentations, sites of infection, comorbidities, microbiological and laboratory findings, antibiotic therapies and LRINEC as well as modified LRINEC scores. The primary outcome was in-hospital mortality.

RESULTS

A cohort of 36 patients, diagnosed with NF, were included in this study. The mean hospital stay was 56 days (±38.2 days). The mortality rate in the cohort was 25%. The sensitivity of the LRINEC score was 86%. Calculation of the modified LRINEC score showed an improvement of the sensitivity to 97%. The average LRINEC score and modified LRINEC score for patients who died and who survived were equal (7.4 versus 7.9 and 10.4 versus 10.0, respectively).

CONCLUSION

The mortality rate of NF remains high. The modified LRINEC score increased the sensitivity in our cohort to 97%, and this scoring system could be supportive in the diagnosis of NF for early surgical debridement.

Seasonal variation characteristics of inhalable bacteria in bioaerosols and antibiotic resistance genes in Harbin

Bioaerosols have received extensive attention due to their impact on climate, ecological environment, and human health. This study aimed to reveal the driving factors that structure bacterial community composition and the transmission route of antibiotic resistance genes (ARGs) in PM_2.5. The results showed that the bacterial concentration in spring (8.76 × 10⁵ copies/m³) was significantly higher than that in summer (1.03 × 10⁵ copies/m³) and winter (4.74 × 10⁴ copies/m³). Low temperatures and air pollution in winter negatively affected bacterial concentrations. Keystone taxa were identified by network analysis. Although about 50 % of the keystone taxa had low relative abundances, the strong impact of complex interactions between keystone taxa and other taxa on bacterial community structure deserved attention. The bacterial community assembly was dominated by stochastic processes (79.3 %). Interactions between bacteria and environmental filtering together affected bacterial community composition. Vertical gene transfer played an important role in the transmission of airborne ARGs. Given the potential integration and expression of ARGs in recipients, the human exposure risk due to high concentrations of ARGs and mobile genetic elements cannot be ignored. This study highlights human exposure to inhalable bacterial pathogens and ARGs in urban areas.

Hemodialysis Patient with Streptococcal Toxic Shock Syndrome and Penile Necrosis

A 72-year-old man on hemodialysis due to diabetic nephropathy presented with a fever and penile pain. Although his physical examination was unremarkable, his general condition deteriorated. Penile necrosis was observed by evening on the same day of presentation, and the patient died the next morning. Blood cultures revealed the presence of Group G Streptococcus, leading to a diagnosis of streptococcal toxic shock syndrome (STSS). Autopsy suggested penile necrosis due to septic shock. STSS in hemodialysis patients with vascular calcification, even in the absence of calciphylaxis, can lead to severe organ damage due to ischemia.

Maternal death due to serious group A streptococcal toxic shock syndrome reduced after the coronavirus disease pandemic in Japan

Purpose: Serious group A streptococcal (GAS) infections and toxic shock syndrome (TSS) are rare conditions, but their rapid progression often results in death. The purpose of the present study was to clarify recent trend after the coronavirus disease (COVID-19) pandemic of GAS infection in Japan.Materials and Methods: Maternal death statistics were analyzed by the Japan Maternal Death Exploratory Committee.Results: Maternal deaths due to GAS-TSS accounted for 4.2% (n = 22) of all maternal deaths in Japan (n = 525) in the last 12 years. GAS-TSS remains one of the leading causes of maternal death after obstetric hemorrhage and hypertensive disorder. However, no maternal deaths due to GAS-TSS have been reported since the COVID-19 pandemic in Japan after the last death occurred in February 2020.Conclusions: The major change during this period was that most Japanese people wore facemasks at all times and did frequent disinfection. It is considered that the reduction in the incidence of GAS infections itself reduced the number of serious GAS-related maternal deaths. Wearing facemasks and frequent disinfection during pregnancy might to be recommended to prevent various infectious diseases including serious GAS infection, even after the COVID-19 pandemic era.

Prospective bacterial and fungal sources of hyaluronic acid: A review

The unique biological and rheological properties make hyaluronic acid a sought-after material for medicine and cosmetology. Due to very high purity requirements for hyaluronic acid in medical applications, the profitability of streptococcal fermentation is reduced. Production of hyaluronic acid by recombinant systems is considered a promising alternative. Variations in combinations of expressed genes and fermentation conditions alter the yield and molecular weight of produced hyaluronic acid. This review is devoted to the current state of hyaluronic acid production by recombinant bacterial and fungal organisms.

Role of Extracellular Trap Release During Bacterial and Viral Infection

Neutrophils are innate immune cells that play an essential role during the clearance of pathogens that can release chromatin structures coated by several cytoplasmatic and granular antibacterial proteins, called neutrophil extracellular traps (NETs). These supra-molecular structures are produced to kill or immobilize several types of microorganisms, including bacteria and viruses. The contribution of the NET release process (or NETosis) to acute inflammation or the prevention of pathogen spreading depends on the specific microorganism involved in triggering this response. Furthermore, studies highlight the role of innate cells different from neutrophils in triggering the release of extracellular traps during bacterial infection. This review summarizes the contribution of NETs during bacterial and viral infections, explaining the molecular mechanisms involved in their formation and the relationship with different components of such pathogens.

Life-threatening complications of streptococcal sepsis: a PICU contemporary series

Background

Life-threatening streptococcal sepsis nowadays represents an uncommon event in previously healthy infants and children. Critically ill patients suffering from severe streptococcal sepsis complications may present with pre-antibiotic era clinical pictures and require a timely clinical approach to achieve restitutio ad integrum.

Results

We report a series of four patient groups affected by an uncommon life-threatening streptococcal sepsis, each of them exhibiting some distinct features. Streptococcus Agalactiae sepsis was associated with cerebral thrombotic/ischaemic lesions, whereas severe cardiogenic shock was prominent in the Streptococcus Viridans group; Streptococcus Faecalis and β-hemolytic group A Streptococcus patients mostly reported lung complications.

Conclusions

Previous antibiotic treatments should not delay aggressive treatment in the intensive care setting. Early diagnostic suspicion, as well as appropriate and aggressive treatment provided within an intensive care setting are crucial for the clinical outcome.

In Silico Core Proteomics and Molecular Docking Approaches for the Identification of Novel Inhibitors against Streptococcus pyogenes

Streptococcus pyogenes is a significant pathogen that causes skin and upper respiratory tract infections and non-suppurative complications, such as acute rheumatic fever and post-strep glomerulonephritis. Multidrug resistance has emerged in S. pyogenes strains, making them more dangerous and pathogenic. Hence, it is necessary to identify and develop therapeutic methods that would present novel approaches to S. pyogenes infections. In the current study, a subtractive proteomics approach was employed to core proteomes of four strains of S. pyogenes using several bioinformatic software tools and servers. The core proteome consists of 1324 proteins, and 302 essential proteins were predicted from them. These essential proteins were analyzed using BLASTp against human proteome, and the number of potential targets was reduced to 145. Based on subcellular localization prediction, 46 proteins with cytoplasmic localization were chosen for metabolic pathway analysis. Only two cytoplasmic proteins, i.e., chromosomal replication initiator protein DnaA and two-component response regulator (TCR), were discovered to have the potential to be novel drug target candidates. Three-dimensional (3D) structure prediction of target proteins was carried out via the Swiss Model server. Molecular docking approach was employed to screen the library of 1000 phytochemicals against the interacting residues of the target proteins through the MOE software. Further, the docking studies were validated by running molecular dynamics simulation and highly popular binding free energy approaches of MM-GBSA and MM-PBSA. The findings revealed a promising candidate as a novel target against S. pyogenes infections.

Streptolysin O concentration and activity is central to in vivo phenotype and disease outcome in Group A Streptococcus infection

Group A Streptoccocus (GAS) is among the most diverse of all human pathogens, responsible for a range of clinical manifestations, from mild superficial infections such as pharyngitis to serious invasive infections such as necrotising fasciitis and sepsis. The drivers of these different disease phenotypes are not known. The GAS cholesterol-dependent cytolysin, Streptolysin O (SLO), has well established cell and tissue destructive activity. We investigated the role of SLO in determining disease outcome in vivo, by using two different clinical lineages; the recently emerged hypervirulent outbreak emm type 32.2 strains, which result in sepsis, and the emm type 1.0 strains which cause septic arthritis. Using clinically relevant in vivo mouse models of sepsis and a novel septic arthritis model, we found that the amount and activity of SLO was vital in determining the course of infection. The emm type 32.2 strain produced large quantities of highly haemolytic SLO that resulted in rapid development of sepsis. By contrast, the reduced concentration and lower haemolytic activity of emm type 1.0 SLO led to translocation of bacteria from blood to joints. Importantly, sepsis associated strains that were attenuated by deletion or inhibition of SLO, then also translocated to the joint, confirming the key role of SLO in determining infection niche. Our findings demonstrate that SLO is key to in vivo phenotype and disease outcome. Careful consideration should be given to novel therapy or vaccination strategies that target SLO. Whilst neutralising SLO activity may reduce severe invasive disease, it has the potential to promote chronic inflammatory conditions such as septic arthritis.

Group A Streptococcal Toxic Shock Syndrome after a Routine Gynecological Procedure

Streptococcal toxic shock syndrome (STSS) is a life-threatening illness mainly caused by invasive group A Streptococcus (GAS) infection. Herein, we report a case of a postmenopausal woman who developed STSS from an ascending vaginal GAS infection after cytocervical sampling. The patient complained of vaginal discharge, for which she underwent gynecological examination with vaginal sampling. The following day, there was onset of diarrhea and vomiting. After 7 days, she was admitted to our hospital with septic shock. Necrotizing enterocolitis was suspected and surgical intervention was performed; however, the patient was diagnosed with primary peritonitis and antibiotics were initiated. On day 2, GAS was suspected by blood cultures, and antibiotics were changed in consideration of STSS. On day 4, GAS was confirmed in blood, ascitic fluid, and vaginal swab specimens, and STSS caused by an ascending vaginal GAS infection was diagnosed. This case report indicates that STSS could occur following cytocervical sampling for vaginal discharge. If a woman has unexplained septic shock, especially with gastroenteritis symptoms, STSS should be considered as a differential diagnosis.

Genital Tract GAS Infection ISIDOG Guidelines

There has been an increasing worldwide incidence of invasive group A streptococcal (GAS) disease in pregnancy and in the puerperal period over the past 30 years. Postpartum Group A streptococci infection, and in particular streptococcal toxic shock syndrome (TSS) and necrotizing fasciitis, can be life threatening and difficult to treat. Despite antibiotics and supportive therapy, and in some cases advanced extensive surgery, mortality associated with invasive group A streptococcal postpartum endometritis, necrotizing fasciitis, and toxic shock syndrome remains high, up to 40% of postpartum septic deaths. It now accounts for more than 75,000 deaths worldwide every year. Postpartum women have a 20-fold increased incidence of GAS disease compared to non-pregnant women. Despite the high incidence, many invasive GAS infections are not diagnosed in a timely manner, resulting in potentially preventable maternal and neonatal deaths. In this paper the specific characteristics of GAS infection in the field of Ob/Gyn are brought to our attention, resulting in guidelines to improve our awareness, early recognition and timely treatment of the disease. New European prevalence data of vaginal GAS colonization are presented, alongside two original case histories. Additionally, aerobic vaginitis is proposed as a supplementary risk factor for invasive GAS diseases.

Molecular characterization and antimicrobial resistance of group A streptococcus isolates in streptococcal toxic shock syndrome cases in Japan from 2013 to 2018

Streptococcal toxic shock syndrome (STSS) is a severe invasive infection characterized by the sudden onset of shock, multi-organ failure, and puerperal sepsis and shows high mortality. Its primary cause is group A streptococcus (GAS, Streptococcus pyogenes). In this study, we genotyped the cell-surface M virulence protein gene (emm) from 621 GAS isolates obtained from patients with STSS in Japan in 2013-2018 and performed antimicrobial susceptibility testing using the broth microdilution method. The predominant emm type was found to be 1, followed by 89, 12, and 3, which were identified in more than 70 % of STSS isolates. The proportions of emm3 and emm89 increased from 2.4 % and 12.0 %, respectively, during 2010-2012 to 5.6 % and 23.3 % during 2013-2018. In contrast, the proportion of emm1 decreased from 60.6 % to 39.3 % during the same two periods. Some emm types showed increasing proportions and were not isolated from patients with STSS in 2010-2012. Among these, an emm76 type increased in prevalence and was not included in the 30-valent M protein-based vaccine. Continual investigation of changes in the epidemiology of GAS which causes STSS can provide useful monitoring information such as future vaccination strategies and the emergence status of antimicrobial-resistant bacteria.

Early intravenous immunoglobulin therapy for group A β-haemolytic streptococcal meningitis with toxic shock syndrome

A woman in her forties was transferred to a Sydney (Australia)-based tertiary hospital, following presentation to a regional hospital with group A Streptococcus (GAS) otomastoiditis; complicated by meningitis, venous sinus thrombosis, haemorrhagic cerebral infarction and subdural empyema. She rapidly deteriorated with profound cardiovascular collapse. Despite initiation of high dose vasoactive therapy, she remained shocked and developed multiorgan dysfunction syndrome. Early intravenous immunoglobulin therapy (140 g in two doses) was initiated as an adjunct to antimicrobial, surgical and supportive care for refractory streptococcal toxic shock syndrome. Over the course of a twelve-day intensive care unit stay she made good progress with de-escalation of her vasoactive supportive care and reversal of her organ injuries. She was subsequently discharged to ward-based care. At her three-month follow-up appointment she had significantly reduced neurological deficit. Five months following her presentation to hospital she had returned to full-time work.

Granadaene Photobleaching Reduces the Virulence and Increases Antimicrobial Susceptibility of Streptococcus agalactiae

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is increasingly recognized as a major cause of soft tissue and invasive diseases in the elderly and diabetic populations. Antibiotics like penicillin are used with great frequency to treat these infections, although antimicrobial resistance is increasing among GBS strains and underlines a need for alternative methods not reliant on traditional antibiotics. GBS granadaene pigment is related to the hemolysin/cytolysin of GBS, which is critical for the pathogenesis of GBS diseases. Here, we show that photobleaching granadaene dampens the hemolytic activity of GBS. Furthermore, photobleaching of this antioxidant was found to increase GBS susceptibility to killing by reactive oxygen species like hydrogen peroxide. Treatment with light was also shown to affect GBS membrane permeability and contribute to increased susceptibility to the cell membrane-targeting antibiotic daptomycin. Overall, our study demonstrates dual effects of photobleaching on the virulence and antimicrobial susceptibility of GBS and suggests a novel approach for the treatment of GBS infection.

Risk factors associated with necrotizing fasciitis of the lower limbs: A multicenter case-control study

OBJECTIVE

The aim of this case-control study was to identify risk factors associated with necrotizing fasciitis (NF) of the lower limbs.

PATIENTS AND METHODS

We conducted a prospective case-control study in hospital dermatology departments in 5 sub-Saharan African countries over a 2-year period (April 2017 to July 2019). The cases were patients with NF of the lower limbs and the controls were patients with leg erysipelas. Each case was matched with two controls for age (±5 years) and sex. We analyzed local and general factors.

RESULTS

During the study period, 159 cases (73 females, 86 males) were matched with 318 controls. The mean age was 48.5±15.8 years for cases and 46.5±16.2 years for controls (P=0.24). The main local signs of NF were cutaneous necrosis (83.7%), pain (75.5%) and induration (42.1%). Multivariate analysis showed the following to be independent risk factors associated with NF of the lower limbs: obesity (odds ratio [OR]=2.10; 95% confidence interval [CI]: 1.21-3.42), diabetes (OR=3.97; 95% CI: 1.95-6.13), nicotine addiction (OR=5.07; 95% CI: 2.20-11.70), use of non-steroidal anti-inflammatory drugs (NSAIDs) (OR=7.85; 95% CI 4.60-14.21) and voluntary cosmetic depigmentation (OR=2.29; 95% CI: 1.19-3.73).

CONCLUSION

Our study documents the role of NSAID use at the onset of symptoms as a risk factor for NF of the lower limbs. However, the originality of our study consists in the identification of voluntary cosmetic depigmentation as a risk factor for NF of the lower limbs in sub-Saharan Africa patients. Our results also identified typical overarching factors such as diabetes, obesity and nicotine addiction. Knowing these factors and taking them into account will enable optimization of management strategies for these conditions.

Necrotizing Soft Tissue Infections

Necrotizing soft tissue infections occur after traumatic injuries, minor skin lesions, nonpenetrating injuries, natural childbirth, and in postsurgical and immunocompromised patients. Infections can be severe, rapidly progressive, and life threatening. Survivors often endure multiple surgeries and prolonged hospitalization and rehabilitation. Despite subtle nuances that may distinguish one entity from another, clinical approaches to diagnosis and treatment are highly similar. This review describes the clinical and laboratory features of necrotizing soft tissue infections and addresses recommended diagnostic and treatment modalities. It discusses the impact of delays in surgical debridement, antibiotic use, and resuscitation on mortality, and summarizes key pathogenic mechanisms.

Antioxidant and antibacterial effects of medicinal plants and their stick-type medicinal concentrated beverages

Nine medicinal plants and their stick-type medicinal concentrated beverages (SMCB-I and SMCB-II) with different combination ratio were evaluated on antioxidant, nitric oxide (NO) inhibitory, and antibacterial effects against pathogenic bacteria involved in respiratory system illnesses. Antioxidant activity was high in Syzygium aromaticum, Pueraria lobata, Plantago asiatica, and Kalopanax pictus which have higher contents of total phenolics and total flavonoids. The NO inhibitory activity was high in Syzygium aromaticum, Plantago asiatica, and Glycyrrhiza uralensis. Syzygium aromaticum, Plantago asiatica, Kalopanax pictus and Glycyrrhiza uralensis showed higher antibacterial activity than the other five medicinal plants against Staphylococcus aureus, Corynebacterium diphtheriae, and Mycobacterium sp. SMCB-II exhibited higher antioxidant, NO inhibitory, and antibacterial effects than SMCB-I, since Syzygium aromaticum, Pueraria lobata, and Kalopanax pictus were only used for the production of SMCB-II. The SMCBs would be expected to contribute to an easy-to-carry, easy-to-consume, and high value-added health beverage for the modern people.

[Invasive Streptococcus pyogenes infections (2011-2018): EMM-type and clinical presentation]

INTRODUCTION

Streptococcus pyogenes (S. pyogenes) is an important human pathogen that is responsible for a broad range of infections, from uncomplicated to more severe and invasive diseases with high morbidity/mortality. The M protein (emm type) is a critical virulence factor. Several studies have shown an increased incidence of invasive S. pyogenes disease. This was associated with an increase in the prevalence of M1 and M3 types, well-recognised virulent M types. The aim of the present study was to confirm the resurgence of invasive S. pyogenes disease during 2011-2018 and to identify the relationship between specific M types with disease presentation.

MATERIAL AND METHODS

Isolates were confirmed using standard techniques: colony morphology, β-haemolysis, biochemical tests, and agglutination with specific antisera (DiaMondiaL Strep Kit, DiaMondiaL, Langenhagen, Germany). The antibiotic sensitivity was performed using microdilution (Vitek®2 Compact, bioMeriéux, Inc., Durham, NC). Molecular analysis included the determination of the emm gene and superantigen profile.

RESULTS

A total of 29 invasive isolates were collected (2011-2018) from blood (16), pleural fluid (9), synovial fluid (3), and cerebrospinal fluid (1). One strain per year was isolated between 2011 and 2013, with 2, 5, 4, 6, and 9 strains being isolated between 2014 and 2018, respectively. The most frequent clinical presentations were bacteraemia and pneumonia (10 and 9 cases). The predominant types were M1 (11 isolates) and M3 (3 isolates). A correlation was found between M1 and M3 types, and pneumonia (6/7 cases) and deep soft tissue infections (3/3 cases).

CONCLUSIONS

An increased incidence of invasive S. pyogenes disease was observed during the study period, with M1 and M3 types being those most commonly isolated and associated with pneumonia and deep soft tissue infections.

Group A Streptococcal Toxic Shock-Like Syndrome in a Male Presenting as Primary Peritonitis: A Case Report and a Review in Japan

BACKGROUND

Streptococcal toxic shock-like syndrome (TSLS) is a severe infection caused by group A hemolytic streptococcus. It is clinically characterized by rapidly progressive septic shock and multiple organ failure within just a few hours. TSLS presenting as primary peritonitis is rare, especially in a male. Herein, we report a case of TSLS in a male presenting with primary peritonitis, with a review of 25 cases in Japan.

CASE PRESENTATION

A 51-year-old male was referred to our hospital with abdominal pain and hypotension. We made a preoperative diagnosis of peritonitis with septic shock and performed an emergency operation. Intraoperative findings indicated no marked origin of the peritonitis. Preoperative blood culture showed the presence of group A hemolytic streptococcus. The patient required intensive care involving artificial respiration, abdominal drainage and cytokine absorption therapy, and was discharged on postoperative day 25.

CONCLUSION

TSLS in a male presenting as primary peritonitis is rare. Although this condition is a severe infection, it can be treated by multimodal therapy.

Fibronectin and Its Role in Human Infective Diseases

Fibronectin is a multidomain glycoprotein ubiquitously detected in extracellular fluids and matrices of a variety of animal and human tissues where it functions as a key link between matrices and cells. Fibronectin has also emerged as the target for a large number of microorganisms, particularly bacteria. There are clear indications that the binding of microorganism’ receptors to fibronectin promotes attachment to and infection of host cells. Each bacterium may use different receptors which recognize specific fibronectin domains, mostly the N-terminal domain and the central cell-binding domain. In many cases, fibronectin receptors have actions over and above that of simple adhesion: In fact, adhesion is often the prerequisite for invasion and internalization of microorganisms in the cells of colonized tissues. This review updates the current understanding of fibronectin receptors of several microorganisms with emphasis on their biochemical and structural properties and the role they can play in the onset and progression of host infection diseases. Furthermore, we describe the antigenic profile and discuss the possibility of designing adhesion inhibitors based on the structure of the fibronectin-binding site in the receptor or the receptor-binding site in fibronectin.

Streptococcus pyogenes peritonitis: a rare, lethal imitator of appendicitis

Streptococcus pyogenes is a common cause of infection. Since 2010, the Centers for Disease Control has noted a 24% rise in invasive S. pyogenes infections with a mortality rate of 10%. We present a case series and review of the English literature. Two patients presented with findings concerning for appendicitis, each underwent laparoscopic appendectomies. Both had diffuse peritoneal inflammation without appendicitis, cultures grew S. pyogenes and both recovered with appropriate antibiotics. Thirty cases were identified in a review of the English literature. The average age was 27 years, 75% were in women, 9% were immunocompromised, 15% had rashes and 88% underwent surgical intervention. Previous work identified female gender, immunosuppression and preceding varicella infection as risk factors for invasive S. pyogenes. Given the similarities to appendicitis, early suspicion can influence antibiotic therapy and possibly improve outcomes.

Recent Advances in the Development of Peptide Vaccines and Their Delivery Systems Against Group A Streptococcus

Group A Streptococcus (GAS) infection can cause a variety of diseases in humans, ranging from common sore throats and skin infections, to more invasive diseases and life-threatening post-infectious diseases, such as rheumatic fever and rheumatic heart disease. Although research has been ongoing since 1923, vaccines against GAS are still not available to the public. Traditional approaches taken to develop vaccines for GAS failed due to poor efficacy and safety. Fortunately, headway has been made and modern subunit vaccines that administer minimal bacterial components provide an opportunity to finally overcome previous hurdles in GAS vaccine development. This review details the major antigens and strategies used for GAS vaccine development. The combination of antigen selection, peptide epitope modification and delivery systems have resulted in the discovery of promising peptide vaccines against GAS; these are currently in preclinical and clinical studies.

Increase in Invasive Group A Streptococcal Disease and Emergence of Mucoid Strains in a Pediatric Population: February-June 2017

Background

Infection with group A Streptococcus (GAS) can cause severe systemic and locally invasive disease. Invasive group A streptococcal (iGAS) disease incidence varies both seasonally and year-to-year, and it may exhibit clustered outbreaks. We observed an upswing in iGAS cases at a tertiary care Children’s Hospital, prompting further characterization of local iGAS disease.

Methods

Cases of iGAS disease were abstracted from the medical record by manual chart review of all positive screening tests and cultures for GAS over a 4-year span. Incidence rates per 1000 hospital admissions and per 100 positive GAS tests were calculated and compared. Selected isolates were further characterized by whole-genome sequencing.

Results

Significant year-to-year differences in per-admission iGAS incidence rate were observed in February and June, although per-positive test incidence rates were not significantly different. Whole-genome sequencing revealed 2 dominant serotypes—emm3 and emm6—with high rates of mucoid phenotype and systemic bacteremia.

Conclusions

We document a significant but transient increase in iGAS disease incidence in 2 months of 2017. Genome sequencing revealed 2 dominant serotypes associated with mucoid phenotypes and severe disease, highlighting the dynamic nature of iGAS disease pattern.

Vaccine Approaches To Protect against Group A Streptococcal Pharyngitis

Streptococcal pharyngitis (or strep throat) is a common childhood disease affecting millions of children each year, but it is one of the only childhood diseases for which a vaccine does not exist. While for decades the development of a vaccine has been the center of attention in many laboratories worldwide, with some successes, no corporate development has yet to be initiated. The reason for this probably lies in our inability to conclusively identify the streptococcal molecule or molecules responsible for the heart cross-reactive antibodies observed in the serum of rheumatic fever patients. Without this specific knowledge, any streptococcal vaccine antigen is suspect and thus not the target for a billion-dollar investment, despite the fact that the exact role of cross-reactive antibodies in rheumatic fever is still questionable. This article will describe the development of several approaches to protect against Streptococcus pyogenes infections over the past several decades.

Sepsis: mechanisms of bacterial injury to the patient

In bacteremia the majority of bacterial species are killed by oxidation on the surface of erythrocytes and digested by local phagocytes in the liver and the spleen. Sepsis-causing bacteria overcome this mechanism of human innate immunity by versatile respiration, production of antioxidant enzymes, hemolysins, exo- and endotoxins, exopolymers and other factors that suppress host defense and provide bacterial survival. Entering the bloodstream in different forms (planktonic, encapsulated, L-form, biofilm fragments), they cause different types of sepsis (fulminant, acute, subacute, chronic, etc.). Sepsis treatment includes antibacterial therapy, support of host vital functions and restore of homeostasis. A bacterium killing is only one of numerous aspects of antibacterial therapy. The latter should inhibit the production of bacterial antioxidant enzymes and hemolysins, neutralize bacterial toxins, modulate bacterial respiration, increase host tolerance to bacterial products, facilitate host bactericidal mechanism and disperse bacterial capsule and biofilm.

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

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

Sepsis and Pleural Empyema Caused by Streptococcus pyogenes after Influenza A Virus Infection

Streptococcus pyogenes (also referred to as group A streptococci, GAS) causes severe invasive diseases such as bacteremia, necrotizing fasciitis, pneumonia, osteomyelitis, septic arthritis, and toxic shock syndrome in children. However, there are only a few reports on pleural empyema caused by GAS in children. Here, we report the case of a 4-year-old boy who presented with pleural empyema due to GAS after influenza A virus infection. With intravenous antibiotic administration and continuous chest-tube drainage, followed by video-assisted thoracoscopic surgery, his condition improved. During the clinical course, cytokines induced in response to the influenza virus, especially IL-1β and IL-10, were elevated 1 week after influenza A infection, but these decreased as the symptoms improved. Reportedly, the IL-10 production increases during influenza virus-bacteria superinfection. These observations suggest that the immunological mechanisms induced by the influenza virus can play an important role in influencing the susceptibility to secondary bacterial infections, such as GAS, in children.

Group A Streptococcal bacteraemia. Experience at King Fahad Medical City in Riyadh, Saudi Arabia

Objectives:

To identify clinical presentation, predisposing factors, and the outcome in patients with Group A Streptococcal bacteremia.

Methods:

This is a retrospective study of 33 pediatric and adult patients with Streptococcus pyogenes bacteremia, admitted at King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia from 2007 to 2015.

Results:

Thirty-three patient records, documenting bacteremia with group A beta-hemolytic streptococcus, were reviewed. Approximately 51.5% were pediatric and 48.5% were adult patients, with a male to female ratio of 2:1. The most frequently reported complications were renal impairment (45.5%) and acute respiratory distress (21.2%), followed by localized infection (15.2%), pleural effusion (6.1%), abscess (9.1%), necrotizing fasciitis (9.1%), septic arthritis, and osteomyelitis (3%). There were 10 episodes of shock: 6 were in pediatric and 4 were in adult patients. At the end of the study period, 12.1% patients died from the illness, 81.1% recovered from illness with no sequelae, while 6.1% recovered with sequelae. Mortality was observed in 4 patients; of them, 3 were pediatric patients and one was an adult with co-morbidities.

Conclusions:

We have noted a minimal change in the disease pattern over the 28 years in Saudi Arabia. The management of invasive GAS infection depends on an accurate and timely diagnosis with an appropriate use of antimicrobial therapy. The highest risks appear to be related to chronic illness. Invasive Group A Streptococcal infection is known to have a high mortality rate.

Foodborne Outbreak of Group G Streptococcal Pharyngitis in a School Dormitory in Osaka, Japan

In September 2016, 140 patients with primary symptoms of sore throat and fever were identified in a school dormitory in Osaka, Japan. Epidemiological and laboratory investigations determined that these symptomatic conditions were from a foodborne outbreak of group G streptococcus (GGS), with GGS being isolated from samples from patients, cooks, and foods. The strain of GGS was identified as Streptococcus dysgalactiae subsp. equisimilis of two emm types (stG652.0 and stC36.0). The causative food, a broccoli salad, was contaminated with the two types of S. dysgalactiae subsp. equisimilis, totaling 1.3 × 10⁴ CFU/g. Pulsed-field gel electrophoresis (PFGE) of samples from patients, cooks, and foods produced similar band patterns among samples with the same emm type. This result suggested the possibility of exposure from the contaminated food. The average onset time was 44.9 h and the prevalence rate was 62%. This is the first report to identify the causative food of a foodborne outbreak by Streptococcus dysgalactiae subsp. equisimilis.

Seasonal variation characteristic of inhalable microbial communities in PM2.5 in Beijing city, China

Bacteria and fungi are primary constituents of airborne microbes in fine particulate matter (PM_2.5) and significantly impact human health. However, hitherto, seasonal variation and effect of air pollution on microbial community composition and structure are poorly understood. This study analyzed the bacterial and fungal composition of PM_2.5 under different air pollution levels during different seasons in Beijing. We altogether collected 75PM_2.5 samples during four seasons from April 2014 to January 2015, under different air pollution levels and employed high-throughput sequencing methods to analyze microbial composition. The results showed that air pollution decreased species richness and community diversity of bacteria in PM_2.5. The variation in bacterial and fungal community composition and structure was significantly related to the season but there was no correlation between their abundance and pollution levels. Pathogenic bacteria and fungi were more abundant in winter than other seasons. To best of our knowledge, this is the first study that demonstrates seasonal variation characteristics of bacteria and fungi in PM_2.5 in heavy haze contaminated areas and highlights the effects of air pollution on the atmospheric microbial community. This study would be useful to other bioaerosol studies focusing on the role of the atmospheric particulate matter on human health.

Enzyme-linked immunosorbent assay for group A Streptococcal anti-DNase B in human sera, using recombinant proteins - Comparison to the DNA methyl green micromethod

Among the four known Streptococcal nucleases comprising of DNase A, B, C and D; DNase B is the most common, and determination of the levels of antibody to DNase B (ADB) is often used to confirm a clinical diagnosis of Streptococcus pyogenes/group A Streptococcal (GAS) infection. The commonly used assays for antibodies that neutralize DNase B or streptolysin O activity use partially purified antigens that often fail to detect antibody changes subsequent to culture documented infections. Therefore, an enzyme-linked immunosorbent assay (ELISA) was developed employing his-tagged recombinant DNase B as plate antigen for comparison to the commonly used DNA methyl green micromethod (DMGM). DNAs from various Streptococcal species were screened for presence of dnaseB gene by PCR. Measurements of ADB in sera collected from subjects belonging to different ages, and ethnic groups were used to compare the two methods. dnaseB was not detected by PCR in DNA samples isolated from different strains of group B (GBS), C (GCS) and G (GGS) Streptococci. The ADB based ELISA proved to be highly sensitive and more responsive to changes in antibody concentration than DMGM. Use of recombinant DNase B eliminates the variability associated with the enzyme, partially purified from Streptococcal culture supernatants from various commercial sources and may provide a more reliable source of antigen to a wider group of laboratories concerned with GAS diagnosis.

Galectin-3 Inhibits Galectin-8/Parkin-Mediated Ubiquitination of Group A Streptococcus

Group A streptococcus (GAS) is an important human pathogen that causes a wide variety of cutaneous and systemic infections. Although originally thought to be an extracellular bacterium, numerous studies have demonstrated that GAS can trigger internalization into nonimmune cells to escape from immune surveillance or antibiotic-mediated killing. Epithelial cells possess a defense mechanism involving autophagy-mediated targeting and killing of GAS within lysosome-fused autophagosomes. In endothelial cells, in contrast, we previously showed that autophagy is not sufficient for GAS killing. In the present study, we showed higher galectin-3 (Gal-3) expression and lower Gal-8 expression in endothelial cells than in epithelial cells. The recruitment of Gal-3 to GAS is higher and the recruitment of Gal-8 to GAS is lower in endothelial cells than in epithelial cells. We further showed that Gal-3 promotes GAS replication and diminishes the recruitment of Gal-8 and ubiquitin, the latter of which is a critical protein for autophagy sequestration. After knockdown of Gal-3 in endothelial cells, the colocalization of Gal-8, parkin, and ubiquitin-decorated GAS is significantly increased, as is the interaction of Gal-8 and parkin, an E3 ligase. Furthermore, inhibition of Gal-8 in epithelial cells attenuates recruitment of parkin; both Gal-8 and parkin contribute to ubiquitin recruitment and GAS elimination. Animal studies confirmed that Gal-3-knockout mice develop less-severe skin damage and that GAS replication can be detected only in the air pouch and not in organs and endothelial cells. These results demonstrate that Gal-3 inhibits ubiquitin recruitment by blocking Gal-8 and parkin recruitment, resulting in GAS replication in endothelial cells.

In epithelial cells, GAS can be efficiently killed within the lysosome-fused autophaosome compartment. However, we previously showed that, in spite of LC-3 recruitment, the autophagic machinery is not sufficient for GAS killing in endothelial cells. In this report, we provide the first evidence that Gal-3, highly expressed in endothelial cells, blocks the tagging of ubiquitin to GAS by inhibiting recruitment of Gal-8 and parkin, leading to an enhancement of GAS replication. We also provide the first demonstration that Gal-8 can interact with parkin, the critical E3 ligase, for resistance to intracellular bacteria by facilitating the decoration of bacteria with ubiquitin chains. Our findings reveal that differential levels of Gal-3 and Gal-8 expression and recruitment to GAS between epithelial cells and endothelial cells may contribute to the different outcomes of GAS elimination or survival and growth of GAS in these two types of cells.

Streptococcal Immunity Is Constrained by Lack of Immunological Memory following a Single Episode of Pyoderma

The immunobiology underlying the slow acquisition of skin immunity to group A streptococci (GAS), is not understood, but attributed to specific virulence factors impeding innate immunity and significant antigenic diversity of the type-specific M-protein, hindering acquired immunity. We used a number of epidemiologically distinct GAS strains to model the development of acquired immunity. We show that infection leads to antibody responses to the serotype-specific determinants on the M-protein and profound protective immunity; however, memory B cells do not develop and immunity is rapidly lost. Furthermore, antibodies do not develop to a conserved M-protein epitope that is able to induce immunity following vaccination. However, if re-infected with the same strain within three weeks, enduring immunity and memory B-cells (MBCs) to type-specific epitopes do develop. Such MBCs can adoptively transfer protection to naïve recipients. Thus, highly protective M-protein-specific MBCs may never develop following a single episode of pyoderma, contributing to the slow acquisition of immunity and to streptococcal endemicity in at-risk populations.

GAS skin infections pose a significant health problem in the tropics. They are highly prevalent in developing countries as well as amongst the Indigenous populations of developed countries. In at-risk impoverished communities the epidemiology of GAS infections is very dynamic, leading to very high rates of streptococcal-associated serious pathology including rheumatic heart disease, glomerulonephritis and invasive GAS disease. Immunity to GAS takes over 20 years to develop and this has been attributed to sequence diversity of the type-specific surface M-protein. There are more than 250 different strains of GAS and it known that antibodies to the amino-terminal segment of the M-protein can kill organisms in a strain-specific manner in vitro. In the present study, using four different strains of GAS isolated from the skin lesions of Aboriginal patients in the Northern Territory of Australia, we make the discovery that skin infection does not induce long-lived type-specific immunity. However, following reinfection with the same strain memory B cells are generated and long-term strain-protective immunity then develops. The dependence on reinfection for the development of strain-specific immunity compounds with antigenic diversity of the M-protein and provides a rational explanation for the very slow acquisition of streptococcal immunity.

Toxic Shock Syndrome

Toxic shock syndrome (TSS) represents a heterogeneous group of disorders that results in hypotension, multiorgan system involvement, and a characteristic rash or soft tissue infection caused by staphylococcal or streptococcal exotoxins and enterotoxins. Staphylococcal TSS emerged in the late 1970s as an illness associated with highly absorbent tampons; subsequently it has been described with postoperative infections, burns, and various viral illnesses. Although the morbidity rate associated with staphylococcal TSS may be high, the mortality rate approximates 5%. Streptococcal TSS has emerged in the 1980s and into the 1990s as a disorder that results in rapid progression of soft tissue infection in the form of cellulitis, myositis, or necrotizing fasciitis due to pyogenic streptococcal group A exotoxin. The rapidity of progression of local infection to hypotension and multiorgan failure results in a mortality rate of 30–70%. In both forms of TSS, staphylococcal and streptococcal exotoxins function as superantigens, a unique mechanism of immune activation that results in an exuberant T-cell response and profound cytokine expression. The role of antibiotics is reviewed. The use of clindamycin in streptococcal TSS and the potential therapeutic role of intravenous immunoglobulin in both forms of this disorder are discussed as well.