Identifying the Strep Threat
The bacteria most commonly associated with surface survival concerns is Streptococcus pyogenes, also known as Group A Streptococcus (GAS). This Gram-positive bacterium often colonizes the throat and skin, and it is responsible for a variety of infections ranging from mild to severe. The most common illness is streptococcal pharyngitis, or strep throat.
GAS is also the causative agent of scarlet fever, a rash-producing illness, and skin infections such as impetigo. Less commonly, it can lead to severe, life-threatening conditions, including necrotizing fasciitis or streptococcal toxic shock syndrome. GAS is the primary public health concern regarding environmental transmission. The spread of GAS typically occurs when an infected person coughs or sneezes, releasing respiratory droplets that contaminate the surrounding environment.
Environmental Factors Determining Survival Time
Survival time is highly dependent on environmental conditions, but under optimal circumstances, the bacteria can persist for hours to several days, and sometimes even for weeks. The primary variables influencing this persistence include moisture, temperature, and the composition of the surface material.
Moisture is a significant factor in bacterial longevity, as GAS is generally fragile outside of its host environment. The bacteria are often contained within respiratory secretions or saliva. The organic components within this dried matter can provide a layer of protection, allowing the organisms to remain viable longer than if they were exposed to dry air alone.
Temperature also plays a role, with cooler conditions typically prolonging the bacteria’s survival time. It can persist longer at room temperature than at elevated temperatures. The type of surface is also important. Porous materials like fabric and paper tend to absorb moisture quickly, which accelerates bacterial death. In contrast, non-porous, hard surfaces such as plastic, glass, and stainless steel may allow the bacteria to survive for several days or even up to a month under laboratory conditions.
Common High-Risk Surfaces and Transfer Methods
The transfer of Group A Streptococcus occurs through a mechanism known as fomite transmission. This involves touching a surface contaminated with respiratory droplets or secretions and then transferring the bacteria to the mouth, nose, or eyes. High-touch surfaces that are frequently handled by multiple people are the most likely vectors for this type of spread.
In a household, common items that can harbor the bacteria include shared personal care items and high-use objects. Shared utensils, dinnerware, and drinking glasses can become contaminated if not properly cleaned between uses.
Objects that are frequently touched, especially by children, pose a risk. These include:
Remote controls
Light switches
Doorknobs
Toys
Stuffed animals, blankets, and bedding
The risk is elevated when these items are touched by an infected person and then quickly handled by a susceptible individual.
Sanitation Protocols for Eradication
Targeted cleaning protocols are the most effective way to eliminate GAS from the home environment. GAS is susceptible to most common household disinfectants, but they must be used correctly to ensure eradication. Cleaning must always precede disinfection, as dirt and organic matter can shield the bacteria from the chemical agent.
Hard Surfaces
For hard, non-porous surfaces, a dilute solution of household bleach is highly effective. General disinfection can be achieved with a bleach solution and a contact time of at least two to five minutes. Alcohol-based disinfectants containing at least $70\%$ alcohol are also suitable for use on metallic surfaces and electronics.
Porous Items and Laundry
Cleaning porous items requires specific measures, especially for laundry and bedding. Soiled linens, towels, and clothing used by an infected person should be washed on a separate cycle. Using the hot water setting, ideally at $60^\circ$C ($140^\circ$F), can effectively destroy the bacteria within the fabric. When hot water washing is not possible for delicate fabrics, the use of a chlorine bleach product in the wash cycle is recommended.