Transmission of group A streptococci: III. The effect of drying on the infectivity of the organism for man

Abstract

The sources of airborne bacteria within living quarters are minute droplet nuclei which remain suspended in the air following expulsion from a carrier and contaminated particles which have become suspended from dried environmental deposits. Since group A streptococci may be isolated from environmental deposits in populations experiencing an epidemic of streptococcal respiratory disease (Loosli, Lemon, Wise & Robertson, 1952), it has been assumed that contaminated particles of dust serve as an important reservoir of infection. Indeed, many of our measures employed to control respiratory infection in recent years have been directed against this reservoir.

An outbreak of scarlet fever in a primary school

“…Contamination of the environment with GABHS was demonstrated, however this was thought to be an unlikely source of infection. Although streptococci are a relatively hardy organism and can survive in the environment, for example, in bedding17 and dust,18 they dry within hours and appear to be non-infectious for pharyngitis 19. However, environmental persistence is a factor in transmission of streptococcal pyoderma 20.…”

To harm or not to harm? On the evolution and expression of virulence in group A streptococci

“…GAS transmit directly [3], but are also shed into the environment where they remain viable for months, and shedding of large numbers of bacteria is associated with high nasal bacterial load [37,38]. These fomites do not seem to give rise to pharyngitis, however, at least not when dry, but can result in other infections [39][40][41][42][43].…”

Streptococcus pyogenes and re-emergence of scarlet fever as a public health problem

“…Person-to-person transmission involves respiratory droplets and direct contact. The bacterium can readily be found in the air and inanimate environment (such as dust and linen) where there are patients with S. pyogenes infections, 38,39,40,41 though environmental objects such as blankets and dusts appeared to be unimportant sources of human infection, presumably due to a reduction in infectivity after desiccation. 40,41 However, since S. pyogenes may survive on the inanimate objects for up to 4 weeks, 42 environmental hygiene and disinfection should be strictly observed especially within institutions and families.…”