Staphylococcus aureus, often called Staph, is a common bacterium found in diverse environments. This spherical microorganism frequently resides as part of the body’s microbiota, inhabiting many niches both within and outside living hosts.
On Human Skin and Mucous Membranes
Staphylococcus aureus commonly resides on healthy human skin and mucous membranes. The nasal passages, particularly the anterior nares, are the most frequent site of colonization, along with other warm, moist areas like the armpits, groin, and perineum. Many individuals carry S. aureus without symptoms, a state known as colonization. Approximately 20% to 30% of the population are persistent carriers, meaning they almost always have S. aureus present. Another 60% are intermittent carriers, carrying the bacterium on and off over time.
In Healthcare Environments
Healthcare settings like hospitals, clinics, and nursing homes are common locations for Staphylococcus aureus. The bacterium can be found on various surfaces, including bed rails, medical equipment, and doorknobs, and may also be present in the air. S. aureus can persist on dry inanimate surfaces for considerable periods, often for months. It can remain viable for at least one week on materials like glass, polyvinyl chloride, stainless steel, and aluminum. The hands of healthcare workers and patients can also harbor Staphylococcus aureus, contributing to its presence.
In Community Settings
Staphylococcus aureus is prevalent in community environments, including public spaces like homes, schools, gyms, and public transportation. The bacterium can survive on inanimate objects and frequently touched surfaces, such as shared gym equipment, doorknobs, and personal items like towels and razors. While its survival on dry surfaces in public areas can be limited, it is commonly found in households, with over 40% potentially colonized.
In Food and Animal Reservoirs
Staphylococcus aureus can be found in certain food products and animal populations. It is commonly present in raw or undercooked meats, poultry, and dairy products. Ready-to-eat foods like salads, cream-filled pastries, and sandwiches are also implicated. Contamination often occurs through improper handling by individuals who carry the bacterium. In animal reservoirs, S. aureus resides on the skin and in the nasal passages of livestock such as cattle, pigs, and poultry. Pets, including dogs and cats, also commonly carry this bacterium, and animals can serve as sources for the bacterium, potentially transmitting it to humans.