Methicillin-resistant Staphylococcus aureus (MRSA) is a type of staph bacteria resistant to several common antibiotics, including methicillin. Many people carry staph without issues, but MRSA can cause infections that are challenging to treat due to this resistance. These infections range from mild skin conditions to more serious illnesses.
How MRSA Spreads and Its Contagious Nature
MRSA primarily spreads through direct skin-to-skin contact with an infected or colonized individual. It can also be transmitted indirectly by touching contaminated surfaces or objects like towels, razors, or athletic equipment. The bacteria can survive on surfaces for days, weeks, or even months. For an infection to establish, MRSA typically needs a break in the skin, such as a cut or scrape.
Individuals can be “colonized” with MRSA, carrying the bacteria without symptoms, or “infected,” having an active illness. Both can spread MRSA. Active infections, especially those with open wounds or drainage, pose a higher transmission risk due to active bacterial shedding. While generally not airborne, MRSA can spread via droplets if a person has MRSA pneumonia and is coughing, particularly in healthcare settings.
Factors Influencing Contagious Duration
The duration an individual remains contagious with MRSA varies. The type of infection plays a significant role; skin and soft tissue infections, like boils or abscesses, are contagious as long as the wound is open, draining, or actively shedding bacteria. More invasive infections, like pneumonia or bloodstream infections, can also be contagious through respiratory droplets or wound discharge, with duration depending on the site and severity.
Effective treatment considerably shortens the contagious period. When appropriate antibiotics are administered and wounds are properly drained, the bacterial load decreases, reducing transmission likelihood. Patients must complete the full course of prescribed treatment, even if symptoms improve, to prevent further resistance. Poor hygiene practices by the individual or their close contacts can prolong contagiousness by facilitating continued spread of the bacteria.
The environment also influences contagiousness. Healthcare settings, such as hospitals and nursing homes, present a persistent challenge due to vulnerable patient populations, frequent contact with healthcare workers, and contaminated surfaces. Rigorous infection control measures are continuously applied in these environments to limit spread.
When Contagion Ends
An individual is considered no longer contagious with an active MRSA infection when symptoms have fully resolved. For skin infections, this means wounds are healed, dry, and no longer producing pus or drainage. Completing the full course of antibiotics or other prescribed treatments is a key indicator that the active infection has been addressed. Adhering to the healthcare provider’s instructions, even if feeling better, helps ensure eradication of the bacteria.
For some individuals, especially those in high-risk professions like healthcare or with recurrent infections, formal clearance testing may be conducted. This involves negative culture tests from specific body sites, such as nasal swabs, to confirm the absence of MRSA colonization. For most community-associated MRSA infections, routine clearance testing is not typically performed. The resolution of visible symptoms and adherence to the full treatment regimen are the primary indicators that the contagious period has ended.
Minimizing MRSA Transmission
Practicing consistent hand hygiene is a primary method to reduce MRSA spread. Frequent and thorough handwashing with soap and water for at least 20 seconds, or using an alcohol-based hand rub when unavailable, helps remove bacteria from the hands. This is especially important after touching wounds or contaminated surfaces.
Proper wound care is another crucial step; cuts, scrapes, and any open sores should be kept clean and covered with dry bandages until healed. This prevents bacteria from spreading to others or surfaces.
Avoid sharing personal items that come into contact with skin or wounds, such as razors, towels, washcloths, or athletic equipment.
Regular cleaning and disinfection of frequently touched surfaces, especially in shared living spaces, also help minimize transmission. Surfaces like doorknobs, light switches, and gym equipment can harbor MRSA for extended periods. Using EPA-registered disinfectants effective against Staphylococcus aureus can reduce the bacterial presence on these surfaces.