Group A Streptococcus (GAS) is the bacterium responsible for common infections like strep throat. This highly contagious pathogen spreads primarily through person-to-person contact via respiratory droplets. Understanding how long GAS remains viable outside the human body, especially on household items, is important for minimizing the risk of spreading the infection at home.
How Long Strep Bacteria Survive on Surfaces
The duration Group A Strep bacteria can persist on a surface varies widely depending on the material and environment. On porous materials like clothing, towels, and linens, the bacteria’s lifespan is generally shorter than on hard, non-porous surfaces. Studies suggest that on fabrics, the bacteria can remain viable for a few hours up to several days.
Environmental factors significantly influence bacterial survival. Moisture and high humidity tend to favor and extend the bacteria’s longevity. Conversely, a dry environment combined with typical room temperature dramatically shortens the pathogen’s survival time. The presence of organic material, such as respiratory secretions, can also provide a protective environment, allowing the bacteria to persist longer. Under laboratory conditions, some strains of Streptococcus pyogenes have survived on dry surfaces for up to a month.
Transmission Through Contaminated Objects
While direct spread through coughing or sneezing remains the dominant mode of transmission, contaminated clothing can play a role in indirect spread, known as fomite transmission. A fomite is any inanimate object capable of carrying infectious organisms. This pathway occurs when an infected person’s respiratory or wound secretions contaminate fabric, such as a shirt or blanket.
The bacteria transfers to a new host when a person touches the contaminated fabric and subsequently touches their mouth, nose, or eyes. Although this is a less common route than direct contact, cleaning items that have been in close contact with a sick individual is a prudent measure. Contaminated fabrics are a particular concern in shared environments where multiple individuals may handle the same item, such as towels or bedding.
Laundry and Cleaning Protocols
Decontaminating clothes and linens used by an infected person requires specific laundry practices. Handle all soiled items as little as possible before washing to prevent the dispersal of bacteria into the air. Avoid shaking the items out, which can release contaminated particles and increase the risk of spread. Soiled laundry should be placed directly into a designated container or bag until it can be washed.
For effective decontamination, the use of hot water is suggested because high temperatures destroy microorganisms. A temperature of at least 71°C (160°F) is commonly recommended for a minimum of 25 minutes to achieve microbial reduction. Adding chlorine bleach to the wash cycle, if safe for the fabric, provides additional safety against the pathogen.
The drying process is an important step in the cleaning protocol. The heat generated by a clothes dryer is highly effective at killing any remaining bacteria, regardless of the wash water temperature. Linens and clothing should be dried completely on a high-heat setting to leverage this microbicidal action.