Macrophages provide the first line of defense against invading pathogens. The aim of this study was to determine the role of macrophages during infection with group A streptococci (Streptococcus pyogenes) in mice. Here, we report that resident macrophages can efficiently take up and kill S. pyogenes during in vivo infection, as demonstrated by immunofluorescence and electron microscopy, as well...

Many studies have shown a correlation between higher consumption of long-acting macrolides and the development of resistance of S. pyogenes but, to our knowledge, no studies have reported the disappearance of S. pyogenes macrolide resistance. We evaluated the possible relationship between the rational use of long-acting macrolide consumption and the disappearance of S. pyogenes erythromycin res...

Pharyngitis caused by Streptococcus pyogenes is one of the most common bacterial infections in humans and is also a starting point for invasive S. pyogenes infection. Here, we describe that tonsil fluid from patients with streptococcal pharyngitis contains high amounts of the interferon (IFN)-dependent CXC chemokine known as monokine induced by IFN- gamma (MIG)/CXCL9. Also in vitro, inflamed ph...

The lbp gene, which encodes a laminin-binding protein (Lbp) of Streptococcus pyogenes, was found in all S. pyogenes M types. An Lbp-deficient mutant showed a significantly lower efficiency of adhesion to HEp-2 cells than did the wild-type strain. These results indicate that Lbp is one of the important S. pyogenes adhesins.

We report 16 bacitracin-resistant Streptococcus pyogenes isolates recovered from pharyngitis patients in Belgium, 14 of which belonged to a particular emm type (emm28). All 16 isolates were constitutively resistant to macrolides and carried erm(B). The emergence of a bacitracin-resistant S. pyogenes clone raises questions about the continued reliability of bacitracin susceptibility testing for ...

Streptococcus pyogenes, one of the major human pathogens, is a unique species since it has acquired diverse strain-specific virulence properties mainly through the acquisition of streptococcal prophages. In addition, S. pyogenes possesses clustered regularly interspaced short palindromic repeats (CRISPR)/Cas systems that can restrict horizontal gene transfer (HGT) including phage insertion. The...

Recent studies have shown that activation of complement and contact systems results in the generation of antibacterial peptides. Streptococcus pyogenes, a major bacterial pathogen in humans, exists in >100 different serotypes due to sequence variation in the surface-associated M protein. Cases of invasive and life-threatening S. pyogenes infections are commonly associated with isolates of the M...

Streptococcus pyogenes is a globally prominent bacterial pathogen that exhibits strict tropism for the human host, yet bacterial factors responsible for the ability of S. pyogenes to compete within this limited biological niche are not well understood. Using an engineered recombinase-based in vivo expression technology (RIVET) system, we identified an in vivo-induced promoter region upstream of...

The serum opacity factor (SOF) of Streptococcus pyogenes is a serotyping tool and pathogenesis factor. Using SOF-coated latex beads in cell adherence assays and antiserum directed against SOF in S. pyogenes-HEp-2 cell adherence inhibition experiments, we demonstrate SOF involvement in the fibronectin-mediated adherence of S. pyogenes to epithelial cells. SOF exclusively targets the 30-kDa N-ter...

OBJECTIVES To type mef genes in a nationwide collection of clinical isolates of Streptococcus pneumoniae and Streptococcus pyogenes as well as pharyngeal carrier strains of viridans streptococci in Norway. METHODS Erythromycin-resistant mef-positive multilocus sequence-typed (MLST) clinical isolates of S. pneumoniae (n = 36) and S. pyogenes (n = 12) from the National Surveillance Program for ...