Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2023

The Missing Piece Surveillance Study: does the pharyngeal microbiome predict risk of acquiring GAS pharyngitis in remote-living children (94066)

Noor-Ul-Huda Dr Ghori 1 2 , Tharushi Pallegedara 1 , Dylan Barth 2 , Janessa Pickering 1 2 , Timothy Barnett 1 2 , Mark Nicol 1 , Asha Bowen 1 2
  1. The University of Western Australia, Perth, WA, Australia
  2. Telethon kids Insititute, Perth, WA, Australia

Introduction

The highly prevalent Group A Streptococcus (GAS) bacterium is responsible for substantial global morbidity and mortality. In Australia, remote-living Aboriginal children are disproportionately affected. Current primary prevention strategies focus on antibiotic treatment of GAS pharyngitis; the stages preceding a sore throat have not been extensively explored. The microbiome is increasingly being acknowledged as having a significant role in human health outcomes. As a component of the Missing Piece Surveillance Study, this sub-study explored the oropharyngeal microbiome before and during oropharyngeal GAS infection using samples collected from school-aged children at two primary schools in the Kimberley region of Western Australia. We hypothesised that there would be a difference in the oropharyngeal microbiome before and during GAS oropharyngeal infection.

 

Methods

We carried out full length 16s rRNA gene sequencing on oropharyngeal samples to address the following aims: (1) compare the microbiome in GAS+ and GAS samples, (2) evaluate the short-term stability of the microbiome in children who remain uninfected with GAS, and (3) explore differences in the baseline oropharyngeal microbiome profile in children who remain uninfected with GAS and children who subsequently develop oropharyngeal GAS infection.

 

Results

From 177 oropharyngeal swabs samples collected from 107 children throughout 2021, 32 were GAS culture-positive. GAS- groups had lower alpha diversity compared to GAS+ groups, indicating dysbiosis. Assessing the short-term stability of the microbiome showed that the microbiome incurred non-significant changes over 3-5 months. Furthermore, compared to the microbiome in children who remained GAS- throughout, children who subsequently developed GAS oropharyngeal infection had lower alpha diversity at baseline, with significant differences in relative abundance of numerous taxa, many of which are opportunistic microbes. As hypothesised, these results indicate that there is a difference in the oropharyngeal microbiome before and during GAS oropharyngeal infection.

These findings support the importance of microbiome studies in understanding disease pathogenesis and may provide opportunities to therapeutically manipulate the oropharyngeal microbiome to prevent infection.

 

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