Standardization of Epidemiological Surveillance of Invasive Group A Streptococcal Infections

Abstract

Invasive group A streptococcal (Strep A) infections occur when Streptococcus pyogenes, also known as beta-hemolytic group A Streptococcus, invades a normally sterile site in the body. This article provides guidelines for establishing surveillance for invasive Strep A infections. The primary objective of invasive Strep A surveillance is to monitor trends in rates of infection and determine the demographic and clinical characteristics of patients with laboratory-confirmed invasive Strep A infection, the age- and sex-specific incidence in the population of a defined geographic area, trends in risk factors, and the mortality rates and rates of nonfatal sequelae caused by invasive Strep A infections. This article includes clinical descriptions followed by case definitions, based on clinical and laboratory evidence, and case classifications (confirmed or probable, if applicable) for invasive Strep A infections and for 3 Strep A syndromes: streptococcal toxic shock syndrome, necrotizing fasciitis, and pregnancy-associated Strep A infection. Considerations of the type of surveillance are also presented, noting that most people who have invasive Strep A infections will present to hospital and that invasive Strep A is a notifiable disease in some countries. Minimal surveillance necessary for invasive Strep A infection is facility-based, passive surveillance. A resource-intensive but more informative approach is active case finding of laboratory-confirmed Strep A invasive infections among a large (eg, state-wide) and well defined population. Participant eligibility, surveillance population, and additional surveillance components such as the use of International Classification of Disease diagnosis codes, follow-up, period of surveillance, seasonality, and sample size are discussed. Finally, the core data elements to be collected on case report forms are presented.

Getting to grips with invasive group A streptococcal infection surveillance in Australia: are we experiencing an epidemic?

“…Global experts offer a broader iGAS case definition, which recommends capturing confirmed (isolation of GAS from a sterile site) as well as probable cases (clinically congruent with severe GAS illness with GAS isolated from a non‐sterile site; for example, maternal sepsis with GAS isolated from the cervix or the placenta). These definitions are intended to provide a comprehensive picture of the burden of iGAS that is consistent with traditional surveillance definitions 31 …”

“…These definitions are intended to provide a comprehensive picture of the burden of iGAS that is consistent with traditional surveillance definitions. 31 Given that the national CDNA case definition does not capture some forms of iGAS, and the relative infancy and the incompleteness of surveillance across all states and territories, the iGAS numbers reflected currently in the NCDS dashboard are likely to be a significant underestimate of the true burden of disease.…”

Fifteen-minute consultation: Group A streptococcal pharyngitis, diagnosis and treatment in children

“…An important additional consideration is the potential prevention of disseminated iGAS disease 13. iGAS manifests in multiple ways including empyema, bacteraemia with pneumonia or skin and soft tissue infection, peritonitis, osteomyelitis, septic arthritis and less commonly meningitis 14. Patients with iGAS may also develop streptococcal toxic shock syndrome, a toxin-mediated GAS complication 14.…”

“…iGAS manifests in multiple ways including empyema, bacteraemia with pneumonia or skin and soft tissue infection, peritonitis, osteomyelitis, septic arthritis and less commonly meningitis 14. Patients with iGAS may also develop streptococcal toxic shock syndrome, a toxin-mediated GAS complication 14. iGAS contributes significantly to GAS global morbidity and has a case fatality rate up to 20% 14.…”

A rise in invasive and non‐invasive group A streptococcal disease case numbers in Melbourne in late 2022

“…The twenty blood culture isolates collected during 2022 were subjected to M‐protein gene ( emm ) typing, a technique for defining the clonal structure of GAS populations 5 . emm type diversity (ten emm types) indicated a non‐clonal outbreak; the most frequent type was emm 1.0 (five isolates).…”