Searching for Strep A in the clinical environment during a human challenge trial: a sub-study protocol

Stephanie L Enkel; Thel K Hla; Bernadette Wong; Janessa Pickering; Timothy C Barnett; Hannah M M Thomas; Nina Lansbury; Jonathan R Carapetis; Laurens Manning; Asha C Bowen

doi:10.1099/acmi.0.000650.v3

Searching for Strep A in the clinical environment during a human challenge trial: a sub-study protocol

Access Microbiol. 2023 Sep 20;5(9):000650.v3. doi: 10.1099/acmi.0.000650.v3. eCollection 2023.

Authors

Stephanie L Enkel^{1

2}, Thel K Hla^{1

2

3}, Bernadette Wong¹, Janessa Pickering^{1

4}, Timothy C Barnett^{1

4}, Hannah M M Thomas¹, Nina Lansbury⁵, Jonathan R Carapetis^{1

2

6}, Laurens Manning^{1

2

3}, Asha C Bowen^{1

2

5

7}

Affiliations

¹ Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Nedlands, WA, Australia.
² Medical School, University of Western Australia, Crawley, WA, Australia.
³ Department of Infectious Diseases, Fiona Stanley Hospital, Murdoch, WA, Australia.
⁴ Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Nedlands, WA, Australia.
⁵ School of Public Health, University of Queensland, Brisbane, QLD, Australia.
⁶ Department of Infectious Diseases, Perth Children's Hospital, Nedlands, WA, Australia.
⁷ Menzies School of Health Research, Darwin, NT, Australia.

Abstract

Streptococcus pyogenes (also known as group A Streptococcus , Strep A) is an obligate human pathogen with significant global morbidity and mortality. Transmission is believed to occur primarily between individuals via respiratory droplets, but knowledge about other potential sources of transmission via aerosols or the environment is limited. Such knowledge is required to design optimal interventions to control transmission, particularly in endemic settings. We aim to detail an experimental methodology to assess the transmission potential of Strep A in a clinical environment. We will examine potential sources of transmission in up to 20 participants recruited to the Controlled human infection for penicillin against Streptococcus pyogenes (CHIPS) Trial. Three approaches to understanding transmission will be used: the use of selective agar settle plates to capture possible droplet or airborne spread of Strep A; measurement of the possible distance of Strep A droplet spread during conversation; and environmental swabbing of personal and common high-touch items to detect the presence of Strep A on hard and soft surfaces. All methods are designed to allow for an assessment of transmission potential by symptomatic, asymptomatic and non-cases. Ethical approval has been obtained through Bellberry Human Research Ethics Committee (approval 2021-03-295). Trial registration number: ACTRN12621000751875. Any results elicited from these experiments will be of benefit to the scientific literature in improving our knowledge of opportunities to prevent Strep A transmission as a direct component of the primordial prevention of rheumatic fever. Findings will be reported at local, national and international conferences and in peer-reviewed journals.

Keywords: Streptococcus pyogenes; epidemiology; infection; transmission.