Comparison of group A streptococcal titres in healthy children and those with pharyngitis and skin infections

Julie Bennett; Nicole J Moreland; Deborah A Williamson; Jonathan Carapetis; Julian Crane; Alana L Whitcombe; Susan Jack; Matire Harwood; Michael G Baker

doi:10.1016/j.jinf.2021.10.014

Comparison of group A streptococcal titres in healthy children and those with pharyngitis and skin infections

J Infect. 2022 Jan;84(1):24-30. doi: 10.1016/j.jinf.2021.10.014. Epub 2021 Oct 25.

Authors

Julie Bennett¹, Nicole J Moreland², Deborah A Williamson³, Jonathan Carapetis⁴, Julian Crane⁵, Alana L Whitcombe², Susan Jack⁶, Matire Harwood⁷, Michael G Baker⁸

Affiliations

¹ Department of Public Health, University of Otago, 23A Mein Street, Newtown, Wellington 6021, New Zealand. Electronic address: julie.bennett@otago.ac.nz.
² Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand; Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand.
³ Peter Doherty Institute for Infection and Immunity, University of Melbourne, Victoria, Australia.
⁴ Telethon Kids Institute and Perth Children's Hospital, University of Western Australia, Perth 6009, Australia.
⁵ Department of Medicine, University of Otago, Wellington, New Zealand.
⁶ Public Health South, Southern District Health Board, Dunedin, New Zealand.
⁷ Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
⁸ Department of Public Health, University of Otago, 23A Mein Street, Newtown, Wellington 6021, New Zealand; Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand.

PMID: 34710392
DOI: 10.1016/j.jinf.2021.10.014

Abstract

Objectives: Rates of acute rheumatic fever, a sequelae of group A Streptococcal (GAS) infection, remain unacceptably high in Indigenous Māori and Pacific children in New Zealand. This prospective study aimed to describe GAS antibody titres in healthy children (5-14 years) by ethnicity, and to determine how paired titres vary with GAS culture positive and negative pharyngitis, and GAS skin infections.

Methods: Analysis included 887 children (32% Māori, 36% Pacific, 33% European/Other) from Auckland, New Zealand. Cases comprise 772 children who had a sore throat or skin infection, which resulted in a swab taken for culture. Healthy controls were asymptomatic (N = 154) and matched by age, ethnicity and region. All participants had a serum sample, with a second sample collected from cases only. Sera were analysed for anti-streptolysin O (ASO) and anti-DNase-B (ADB) antibodies.

Results: Healthy Māori and Pacific children had higher GAS antibody titres than healthy European/Other children. Children with GAS-positive sore throat had the highest mean ASO titres and children with GAS-positive skin infection had the highest mean ADB titres. When a two-fold increase or an upper limit of normal cut-off (ASO 450 IU/ml, ADB 400 U/ml) was applied to titres from children with GAS-positive sore throat, 62.1% were classified as having serologically confirmed GAS pharyngitis and 37.9% had GAS detected without serological response.

Conclusions: Elevated ASO titres were associated with GAS pharyngitis and elevated ADB titres were associated with GAS skin infections in New Zealand children. Higher ASO/ADB titres in healthy Māori and Pacific children could indicate a greater prior exposure to GAS infections.

Keywords: Anti-DNase-B; Anti-streptolysin O; Children; Group A Streptococcus; Pharyngitis; Serology; Skin infection.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Child
Humans
Pharyngitis*
Prospective Studies
Rheumatic Fever*
Streptococcal Infections*
Streptococcus pyogenes