Group AStreptococcusAntibiotic Resistance in Southern Brazil: A 17-Year Surveillance Study

A global snapshot on the prevalent macrolide-resistant emm types of Group A Streptococcus worldwide, their phenotypes and their resistance marker genotypes during the last two decades: A systematic review

Watchful epidemiological surveillance of macrolide-resistant Group A Streptococcus (MRGAS) clones is important owing to the evolutionary and epidemiological dynamic of GAS. Meanwhile, data on the global distribution of MRGAS emm types according to macrolide resistance phenotypes and genotypes are scant and need to be updated. For this, the present systematic review analyses a global set of extensively characterized MRGAS isolates from patients of diverse ages and clinical presentations over approximately two decades (2000 to 2020) and recaps the peculiar epidemiological features of the dominant MRGAS clones. Based on the inclusion and exclusion criteria, 53 articles (3593 macrolide-resistant and 15,951 susceptible isolates) distributed over 23 countries were dissected with a predominance of high-income countries over low-income ones. Although macrolide resistance in GAS is highly variable in different countries, its within-GAS distribution seems not to be random. emm pattern E, 13 major emm types (emm12, 4, 28, 77, 75, 11, 22, 92, 58, 60, 94, 63, 114) and 4 emm clusters (A-C4, E1, E6, and E2) were significantly associated with macrolide resistance. emm patterns A-C and D, 14 major emm types (emm89, 3, 6, 2, 44, 82, 87, 118, 5, 49, 81, 59, 227, 78) and 3 well-defined emm clusters (A-C5, E3, and D4) were significantly associated with macrolide susceptibility. Scrutinizing the tendency of each MRGAS emm type to be significantly associated with specific macrolide resistance phenotype or genotype, interesting vignettes are also unveiled. The 30-valent vaccine covers ~95% of MRGAS isolates. The presented data urge the importance of comprehensive nationwide sustained surveillance of MRGAS circulating clones particularly in Low and Middle income countries where sampling bias is high and GAS epidemiology is obfuscated and needs to be demystified.

Antimicrobial Resistance among Beta-Hemolytic Streptococcus in Brazil: An Overview

Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus dysgalactiae subsp. equisimilis (SDSE) are the beta-hemolytic streptococci species with the most clinical relevance to humans. These species are responsible for several infections, ranging from mild to life-threatening diseases. Although resistance to recommended drugs has not been so critical as detected in other species, it has occurred in diverse regions. In Brazil, it is possible to observe an increasing macrolide and lincosamide resistance trend due to the spread of polyclonal strains. Macrolide-lincosamide-streptogramin B (MLS) resistance phenotypes have been prevalent among S. agalactiae and S. pyogenes, while M phenotype (resistance only to macrolides) has prevailed among SDSE resistant isolates. Fluoroquinolone resistance is rare in this country, reported only in S.agalactiae and S.pyogenes. This is due to nucleotide substitutions in gyrA and parC genes. Reduced penicillin susceptibility and vancomycin resistance, detected in other regions, have not yet been reported in Brazil. Tetracycline is not a therapeutical option, and resistance has occurred at high levels, especially among S.agalactiae. These findings highlight the need for continuous monitoring in order to track the occurrence of antimicrobial resistance among beta-hemolytic streptococci species circulating in this country.

Invasive Group A Streptococcus Infection in Children in Central Israel in 2012-2019

BACKGROUND

Group A Streptococcus can cause serious and sometimes life-threatening disease in children. The past few years have witnessed a rise in invasive group A Streptococcus infection (iGASi) for unclear reasons. This study attempted to describe the epidemiology, the clinical and demographic characteristics and the outcomes associated with iGASi in hospitalized children in central Israel.

METHODS

We retrospectively analyzed the medical records of children <18 years old discharged with a diagnosis of iGASi between January 2012 and December 2019. Clinical, laboratory and microbiologic data, and immunization status were retrieved. The patients were divided into severe and nonsevere groups based on their clinical presentation. The emm type was determined at the national reference center.

RESULTS

A total of 167 patients with 206 positive cultures for group A Streptococcus were identified. Hospitalizations for iGASi increased from 701 to 958 per 100,000 admissions between 2012-2015 and 2016-2019, respectively, representing an increase of 37%. The majority of the isolates were from the otolaryngologic system followed by blood, deep soft tissue and respiratory sites. Uncomplicated mastoiditis was the most common diagnosis, followed by bacteremia. Pneumonia was the main diagnosis in the severe group (39.4%).

CONCLUSIONS

The admissions because of iGASi in children <18 years old increased during the last 8 years. Surveillance systems and prospective studies should be conducted to expend our understanding of the epidemiology of iGASi in children, better assess the pathogenesis and specific risk factors and monitor changes in emm-type distribution.

Pulse therapy combined with oral corticosteroids in the management of severe rheumatic carditis and rebound

OBJECTIVE

The aim of the present study was to describe the clinical course, laboratory tests, and the cardiac involvement in rheumatic carditis patients in functional class III and IV, submitted to pulse therapy combined with oral prednisone.

METHODS

A total of 120 patients with severe carditis due to acute rheumatic fever were treatment with three cycles of pulse therapy combined with oral corticosteroids. The patients were followed up from the hospital admission until the end of the treatment and returned after 30, 60, and 90 days to control. The patients were evaluated by clinical, laboratory, and transthoracic echocardiogram.

RESULTS

In total, 23 (19.2%) patients at first attack of rheumatic fever and 97 (80.8%) with recurrent carditis were evaluated. Cardiac surgery was performed in 8 (6.6%) patients. The patients showed improved laboratory and radiological parameters (p<0.001) and were discharged, 74 (61.7%) in functional class I and 46 (38.3%) in functional class II. Hospitalisation time ranged from 21 to 176 days, with a mean of 69.1 days. Reduction of left atrium and ventricle diameters was observed, measured by means of transthoracic echocardiography, at hospital admission and discharge (p<0.001). None of the patients experienced rebound.

CONCLUSIONS

The pulse therapy was effective in controlling severe rheumatic carditis and the oral corticosteroid prevented rebound episodes. Prolonged hospital stay was required for the clinical stabilisation of patients and to avoid the interruption of medication.

Management of Contacts of Patients With Severe Invasive Group A Streptococcal Infection

BACKGROUND

Conflicting recommendations regarding antibiotic prophylaxis for contacts of patients with invasive group A streptococcal (GAS) infection exist. Close contacts of patients with such severe and rapidly progressive disease often strongly appeal to the treating clinicians for antimicrobial treatment to prevent additional cases. We aimed to use an approach based on pharyngeal culture testing of contacts and targeted antibiotic prophylaxis.

METHODS

A large throat swab survey including 105 contacts was undertaken after a fulminant and fatal case of GAS necrotizing fasciitis. GAS strains were characterized by emm typing and antimicrobial susceptibility to 7 antibiotics. The presence of 30 virulence determinants was determined by polymerase chain reaction and sequencing.

RESULTS

The GAS isolate recovered from the index patient was an M1T1 GAS clone susceptible to all antimicrobial agents tested. The same clone was present in the throat of 36% of close contacts who had exposure to the index patient (family households and classroom contacts) for >24 hours/week, whereas the strain was present in only 2% of the other contacts.

CONCLUSIONS

Although the study does not allow firm conclusions to be drawn as to whether antibiotic prophylaxis is effective, we describe a practical approach, including an educational campaign and targeted antibiotic treatment to close contacts who have been exposed to an index patient for > 24 hours/week before the initial disease onset.

Antimicrobial susceptibility patterns, emm type distribution and genetic diversity of Streptococcus pyogenes recovered in Brazil

Streptococcus pyogenes is responsible for a variety of infectious diseases and immunological complications. In this study, 91 isolates of S. pyogenes recovered from oropharynx secretions were submitted to antimicrobial susceptibility testing, emm typing and pulsed-field gel electrophoresis (PFGE) analysis. All isolates were susceptible to ceftriaxone, levofloxacin, penicillin G and vancomycin. Resistance to erythromycin and clindamycin was 15.4%, which is higher than previous reports from this area, while 20.9% of the isolates were not susceptible to tetracycline. The macrolide resistance phenotypes were cMLSB (10) and iMLSB (4). The ermB gene was predominant, followed by the ermA gene. Thirty-two emm types and subtypes were found, but five (emm1, emm4, emm12, emm22, emm81) were detected in 48% of the isolates. Three new emm subtypes were identified (emm1.74, emm58.14, emm76.7). There was a strong association between emm type and PFGE clustering. A variety of PFGE profiles as well as emm types were found among tetracycline and erythromycin-resistant isolates, demonstrating that antimicrobial resistant strains do not result from the expansion of one or a few clones. This study provides epidemiological data that contribute to the development of suitable strategies for the prevention and treatment of such infections in a poorly studied area.

Draft Genome Sequence of Streptococcus pyogenes Strain 06BA18369, a Human Pathogen Associated with Skin and Soft Tissue Infections in Northern Canada

We report the draft sequence of Streptococcus pyogenes 06BA18369 (emm type 41.2, sequence type 579 [ST579]), isolated from a skin and soft tissue infection (SSTI) mixed with Staphylococcus aureus. This genome provides insight into the genetic composition of S. pyogenes strains associated with mixed SSTIs.

Group A streptococcus meningitis in children

OBJECTIVE

To characterize the epidemiologic burden and the molecular determinants of group A streptococcal (GAS) meningitis among the pediatric population of the state of Paraná, Brazil.

METHODS

Clinical and epidemiologic data were gathered by a compulsory notification system during the period 2003 to 2011. Bacterial identification, antibiotic resistance profile, emm-typing, pulsed-field gel electrophoresis typing and virulence profile were analyzed by a central reference laboratory. A review of published pediatric cases of GAS meningitis from the last 45 years was undertaken and compared with the Brazilian series.

RESULTS

The incidence of GAS meningitis among the pediatric population was 0.06 cases per 100,000 children per year and was associated with a case fatality rate of 43%. Neonatal age and the presence of an associated toxic shock syndrome were identified as risk factors for death. A distant focus of infection was present in more than half of the patients in the literature and in 36% in the Brazilian case series. A high diversity of emm-types was associated with GAS meningitis in Brazil. No single virulence determinant could be associated with death.

CONCLUSIONS

GAS meningitis is associated with high mortality and with a high diversity of GAS emm-types and virulence determinants in Brazil.