title: Group A streptococci in the 1990s.
abstract: The last decade has witnessed a remarkable change in the epidemiology of group A streptococcal infections. There has been a marked increase globally in the reporting of invasive infections caused by Streptococcus pyogenes, Lancefield group A streptococci. Many of these cases were deep-seated infections associated with shock and multi-organ failure and are defined as streptococcal toxic shock syndrome. In addition, reports of streptococcal sequelae, in particular, acute rheumatic fever, have re-emerged and remain a serious health threat in developed countries. It appears that these infections are related to the type distributions of the organism among the general population, with the re-emergence of more 'virulent' strains, such as the M1 serotype which in earlier decades was primarily seen in cases of either superficial disease or scarlet fever. Population-based surveillance studies have clearly indicated the importance and relevance of type identification for epidemiological purposes. There have also been suggestions that certain extracellular products and toxins play a major role in the so-called 'increased virulence' of the organism; these include cell surface molecules such as the M protein, opacity factor, the hyaluronic acid capsule, C5a peptidase and streptococcal inhibitor of complement (SIC), in addition to secreted proteins, pyrogenic exotoxins, cysteine proteinase, streptolysins O and S, hyaluronidase, streptokinase and other enzymes. All these factors, and events during the last decade, strongly emphasize the need for a better understanding of the epidemiology, pathogenesis, treatment and prevention of group A streptococcal infections.
authors.affiliation: WHO Collaborating Centre for Diphtheria and Streptococcal Infections, PHLS Respiratory and Systemic Infection Laboratory, Central Public Health Laboratory, London, UK. aefstratiou@phls.nhs.uk
authors.forename: A
authors.initials: A
authors.lastname: Efstratiou
mesh_terms: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D004739:England / Q000453:epidemiology; D006801:Humans; D012703:Serotyping; D013290:Streptococcal Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000145:classification / Q000276:immunology / Q000472:pathogenicity; D014774:Virulence; D014852:Wales / Q000453:epidemiology
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein