Throat-dwelling bacteria to be a primary source of Strep A transmission

Breakthrough research has found that Group A Streptococcus (GAS) infections are more likely transmitted from asymptomatic throat carriage than skin-to-skin contact in communities with high rates of infection.

GAS (Streptococcus pyogenes), commonly found on the skin and in the throat, can cause infections ranging from sore throats and impetigo (skin infections) to deadly bloodstream infections. In places like remote First Nations communities where the pathogen is widespread, constant exposure to GAS can lead to severe and life-threatening conditions such as rheumatic heart disease.

In this study, published in the journal The Lancet Microbe, the team of scientists sheds new light on GAS transmission dynamics in high-risk settings where the bacteria are prevalent, to inform the development of more effective strategies for prevention and control.

Researchers analyzed the genetic makeup of hundreds of GAS bacterial samples collected 20 years ago from throats and impetigo lesions in remote First Nations communities in the Northern Territory, Australia.

Lead author Dr. Jake Lacey explains, “Our analysis revealed direct connections between isolates recovered from the skin and throat, challenging common thinking that skin-to-skin contact is the primary mode of transmission. In fact, we found that bacteria found in the throat of people who are not showing any symptoms of infections were the likely source of infection in 63 percent of cases,”

Reference: Evaluating the role of asymptomatic throat carriage of Streptococcus pyogenes in impetigo transmission in remote Aboriginal communities in Northern Territory, Australia: a retrospective genomic analysis, The Lancet Microbe, DOI 10.1016/S2666-5247(23)00068-X