Strep throat is a common bacterial infection caused by Streptococcus pyogenes, also known as Group A Streptococcus (GAS). This bacterium typically lives in the nose and throat of an infected person, causing symptoms like sore throat and fever. Since the infection spreads via respiratory droplets, people often wonder how long the bacteria can survive outside the body and contaminate the environment. Understanding the survival capacity of this pathogen on porous surfaces like bedding is important for effective household infection control. This article explores the evidence for Group A Strep’s ability to survive on bedding and outlines practical measures to reduce potential risk.
Viability of Group A Streptococcus on Surfaces
Group A Streptococcus can remain viable on inanimate objects, known as fomites, for long periods after being shed. Scientific studies show that the survival time of S. pyogenes on a dry surface is highly variable, potentially ranging from a few days up to several months. This extended survival is concerning for porous materials that are difficult to clean, such as textiles.
The specific type of material and environmental conditions heavily influence how long the bacteria persist. On synthetic fibers like polyester, S. pyogenes has been observed to survive for over 200 days in laboratory settings. Even on cotton, a common bedding material, the bacteria can remain viable for over a month. Paradoxically, the bacteria’s survival is enhanced in desiccated conditions, which helps explain its persistence outside the moist environment of the human body.
Assessing the Actual Risk of Fomite Transmission
Despite the bacteria’s ability to survive for long periods on surfaces, direct person-to-person contact remains the primary route of Strep transmission. The bacteria are most often spread through respiratory droplets released when an infected person coughs or sneezes, or through direct contact with their secretions. Transmission via contaminated objects, or fomites, is considered a possible but less common route for the spread of Group A Strep.
For infection to occur from a surface, a sufficient number of live bacteria must be transferred from the fomite to a person and then enter the body, typically through the mouth or nose. This required amount is known as the infectious dose. The bacterial load transferred from touching a contaminated blanket is usually much lower than the load received from a direct cough. Studies involving people with Strep pharyngitis have shown minimal evidence of Strep A transmission via environmental surfaces.
Essential Cleaning and Disinfection Protocols
Given the confirmed viability of S. pyogenes on textiles, cleaning and disinfection protocols are important for mitigating the risk of spread within the household. All bedding, including sheets, pillowcases, and blankets used by an infected person, should be washed separately from other household laundry. The most effective method for eliminating the bacteria from fabric is using high heat during the wash cycle.
Many modern washing machines feature a dedicated sanitize cycle, which uses extra-hot water to eliminate a high percentage of common bacteria, including Strep. If a sanitize cycle is not available, the hottest water setting appropriate for the fabric should be used. Adding an EPA-registered disinfectant, such as liquid chlorine bleach, to the wash cycle can further ensure bacterial elimination.
For items that cannot tolerate high heat or bleach, a commercial laundry sanitizer should be used according to the product’s instructions. Beyond bedding, surrounding high-touch, hard surfaces, such as nightstands, doorknobs, and light switches, should also be disinfected. Use an appropriate surface disinfectant with a kill claim against bacteria, following the required contact time listed on the product label.