Invasive Streptococcus pyogenes infections in children.

We investigated the epidemiology and clinical features of invasive S. pyogenes infection in a pediatric population over a 7-year period (1984-90) by retrospective review. An increasing frequency in invasive infections had occurred (0-11.81/10,000 admissions). A large proportion (48%) of these were orthopedic infections. An epidemic strain was typed as M1T1. This increase appears to have occurred in the context of an overall increase in S. pyogenes infections ("scarlet fever" 1.47-11.22/10,000 outpatients; "strep throat" 4.41-46.54/10,000 outpatients).     

Global genomic epidemiology of Streptococcus pyogenes

Streptococcus pyogenes is one of the Top 10 human infectious disease killers worldwide causing a range of clinical manifestations in humans. Colonizing a range of ecological niches within its sole host, the human, is key to the ability of this opportunistic pathogen to cause direct and post-infectious manifestations. The expansion of genome sequencing capabilities and data availability over the last decade has led to an improved understanding of the evolutionary dynamics of this pathogen within a global framework where epidemiological relationships and evolutionary mechanisms may not be universal. This review uses the recent publication by Davies et al., 2019 as an updated global framework to address S. pyogenes population genomics, highlighting how genomics is being used to gain new insights into evolutionary processes, transmission pathways, and vaccine design.     

Clonal structure of invasive Streptococcus pyogenes in Northern Scotland.

We have used molecular techniques to characterize 51 group A streptococci from Scotland and 17 ''serious disease'' isolates from other countries, in order to establish the clonal structure of invasive Streptococcus pyogenes strains circulating between 1986 and 1993. Strains were grouped by restriction endonuclease analysis, pulsed field gel electrophoresis and ribotyping patterns, and were examined for the presence of alleles of the speA gene by polymerase chain reaction and DNA sequence analysis. Serious and fatal infections in Scotland were caused by several clones. One clone (9 of 51 strains) was M type 1 and possessed the speA gene allele 2. This was the clone previously identified as causing severe infection in the USA. Another clone (5 of 51 strains) was M type 3 and had speA gene allele 3. In view of the clear association of more than one clone with severe, invasive and fatal infections, horizontal gene exchange between genotypes merits further investigation.     

Erythromycin resistance in Streptococcus pyogenes in Italy

In a prospective study of acute pharyngitis in Italian children, 69 (38.3%) of 180 isolates of Streptococcus pyogenes were resistant to macrolides. S. pyogenes was eradicated in 12 (63.1%) of 19 patients with erythromycin-resistant S. pyogenes treated with clarithromycin and in 22 (88%) of 25 patients with erythromycin-susceptible strains. The constitutive-resistant phenotype was correlated with failure of macrolide treatment.     

Streptococcus pyogenes vulvovaginitis in children in Nottingham

Isolates of Streptococcus pyogenes from vaginal swabs of children with vulvovaginitis received at Nottingham Public Health Laboratory during 1986-9 were studied. A total of 159 isolates was made during the 4 years, increasing from 17 in 1986 to 64 in 1989 and accounting for 11% of all vaginal swabs received from children. The numbers of throat swabs yielding S. pyogenes also showed an increase from 974 in 1986 to 1519 in 1989. A winter peak of isolates was noted for both vaginal swabs and throat swabs. A total of 98 strains from vaginal swabs were serotyped: 22 different types were identified, 61% of which were the common types M4, M6, R28 and M12. Erythromycin sensitivity was done on 89 strains; 84% were highly sensitive (MIC less than 0.03 mg/l). There are no other reports of such large numbers in the literature; the reason for seeing this increase in Nottingham is unclear.     

Antibiotic selection pressure and resistance in Streptococcus pneumoniae and Streptococcus pyogenes

We correlated outpatient antibiotic use with prevalence of penicillin-nonsusceptible Streptococcus pneumoniae (PNSP), macrolide-resistant S. pneumoniae (MRSP), and macrolide-resistant S. pyogenes (MRGAS) in 20 countries. Total antibiotic use was correlated with PNSP (r = 0.75; p < 0.001), as was macrolide use with MRSP (r = 0.88; p < 0.001) and MRGAS (r = 0.71; p = 0.004). Streptococcal resistance is directly associated with antibiotic selection pressure on a national level.     

Invasive Streptococcus pyogenes after allograft implantation--Colorado, 2003

Allograft tissues are used for various orthopedic procedures (e.g., ligament reconstruction, meniscal transplantation, and spinal surgery). In 2002, approximately one million allografts were distributed for transplantation (American Association of Tissue Banks [AATB], unpublished data, 2002). Recent reports of allograft-associated infections have prompted evaluation of the processing and quality-control methods employed by tissue processors. This report describes a case of invasive disease with Streptococcus pyogenes (i.e., group A streptococcus [GAS]), after reconstructive knee surgery using contaminated allograft tissue and provides recommendations to reduce the risk for allograft-associated infections. Although allograft infections are rare, they highlight the need for improved tissue evaluation and processing standards.     

Clonal differences among erythromycin-resistant Streptococcus pyogenes in Spain

The aim of this study was to determine whether the high levels of erythromycin resistance in Streptococcus pyogenes found in Spain are due to the introduction and spread of one or more clones. Phenotypic and genotypic techniques were used to characterize all erythromycin-resistant S. pyogenes (ErR) isolated in Gipuzkoa, Spain, in the last 10 years and 128 ErR isolated in Vitoria and Madrid during 1996. Of 437 ErR, 97% had the M phenotype; all 283 of the strains studied had the mefA determinant of resistance. After biotyping, T serotyping, emm typing, and genotyping, four major clones were detected. Clones B (biotype I, type T4, emm4, pulsed-field gel electrophoresis [PFGE] II) and D (biotype V, type T8.25, emm75, PFGE IV) comprised 78.8% of all ErR. The resistance of S. pyogenes to erythromycin was mainly due to an efflux mechanism of resistance (M phenotype); few clones were responsible for it.     

Antimicrobial Drug Use and Macrolide-Resistant Streptococcus pyogenes, Belgium

In Belgium, decreasing macrolide, lincosamide, streptogramins B, and tetracycline use during 1997-2007 correlated significantly with decreasing macrolide-resistant Streptococcus pyogenes during 1999-2009. Maintaining drug use below a critical threshold corresponded with low-level macrolide-resistant S. pyogenes and an increased number of erm(A)-harboring emm77 S. pyogenes with low fitness costs.     

Toxic shock-like syndrome associated with necrotizing Streptococcus pyogenes infection

Two patients with toxic shock-like syndrome are presented. Both patients had necrotizing cellulitis due to Streptococcus pyogenes, and both patients required extensive surgical debridement. The association of Streptococcus pyogenes infection and toxic shock-like syndrome is discussed.     

Azithromycin-sulfonamide conjugates as inhibitors of resistant Streptococcus pyogenes strains

Novel hybrid compounds 6a-6d, conjugates of 15-membered azalides and sulfonamides, i.e. unsubstituted, 4-aryl- and 4-heteroaryl-aminosulfonyl derivatives of 9a-[N'-(phenylcarbamoyl)]-9-deoxo-9-dihydro-9a-aza-9a-homoerythromycin A were synthesized and characterized by IR, one- and two-dimensional NMR spectroscopies and MALDI-TOF and MS/MS mass spectrometry. The new compounds were evaluated in vitro against a panel of sensitive and resistant Gram-positive and Gram-negative bacterial strains. 9a-{N'-[4-(Aminosulfonyl)phenyl]carbamoyl}--(6a) and 9a-{N'-[4-(phenylaminosulfonyl)phenyl]carbamoyl}--(6b) derivatives showed improvements in activity against inducible resistant Streptococcus pyogenes in comparison with macrolide antibiotic azithromycin and starting material 9-deoxo-9-dihydro-9a-aza-9a-homoerythromycin A (2). In addition, the synthesized azithromycin-sulfonamide conjugates 6a-6d showed good antibacterial activity against sensitive S. pyogenes and Streptococcus pneumoniae strains. The kinetics of degradation in the artificial gastric juice showed that the most active compounds, 6a and 6b, exhibited azithromycin like stability. The cleavage of the cladinose sugar was found to be the main decomposition pathway leading to inactive 7a and 7b, prepared also as analytical standards by the alternative synthetic route together with 7c and 7d.     

Streptococcus pyogenes: an outbreak on a burns unit

An outbreak of infection with Streptococcus pyogenes (Group A beta-haemolytic streptococcus) on a burns unit described. The control measures taken are outlined, and the route of spread of infection is discussed along with possible preventative measures.