You get a staph infection when Staphylococcus aureus bacteria enter your body through a break in the skin, such as a cut, scrape, surgical wound, or even a tiny nick from shaving. About 30% of people already carry staph bacteria in their noses or on their skin without any problems. Infection happens when the bacteria move past your skin’s protective barrier and into deeper tissue or the bloodstream.
Staph Already Lives on Your Body
Roughly one in three people carries staph bacteria, usually in the nostrils or on the skin’s surface, and never develops an infection. Your skin acts as a highly effective barrier, with layers of tightly connected cells that keep bacteria on the outside. Staph only becomes a problem when that barrier is compromised. A paper cut, a scraped knee, a surgical incision, a cracked patch of eczema, or even a clogged hair follicle can give the bacteria an opening.
Once inside, staph produces proteins that break down the connections between skin cells, weakening the barrier further and allowing the infection to spread. This is why a small wound that seems insignificant can turn into a red, swollen, painful area within a day or two. The bacteria are essentially dismantling your skin’s defenses from the inside out.
Skin-to-Skin Contact and Shared Items
Staph spreads easily through direct skin contact with someone who carries the bacteria. It also spreads through contaminated objects. Sharing towels, razors, bed sheets, or other personal hygiene items with someone who carries staph is one of the most common ways the bacteria move between people. In household settings, the risk of transmission increases significantly when people share bedrooms, beds, or bath towels.
This is why staph outbreaks are common in close-contact settings: wrestling teams, military barracks, dormitories, and locker rooms. The combination of skin-to-skin contact, shared equipment, and minor skin abrasions from physical activity creates ideal conditions for transmission.
How Long Staph Survives on Surfaces
Staph bacteria are surprisingly durable on surfaces. On indoor materials like polyethylene and synthetic turf, staph can survive anywhere from 22 to 40 days under favorable conditions with limited light and moderate temperatures. Even surfaces treated with antimicrobial agents still harbored live bacteria for at least nine days in controlled studies conducted at Penn State.
Outdoors, the story changes. UV light and higher temperatures kill staph much faster. In outdoor conditions, bacterial counts dropped to nearly undetectable levels within three hours, and no live bacteria were found after 72 hours. This is worth knowing if you use gym equipment, wrestling mats, or shared athletic gear indoors, where the bacteria can linger far longer than most people assume. Wiping down equipment before use is a practical step that actually matters.
Hospital and Healthcare Settings
Healthcare settings carry a heightened risk because patients often have exactly the kind of skin barrier disruptions that staph exploits: surgical incisions, IV lines, catheters, and weakened immune systems. Central venous catheters, which are placed directly into large veins, are a particularly common pathway for staph to enter the bloodstream. Invasive procedures and surgeries involving the heart, bones, joints, or spine also carry elevated risk.
This is also where drug-resistant strains like MRSA become a serious concern. Hospital-onset MRSA bloodstream infections increased during 2020 through 2022, partly driven by patients with recent COVID-19 infections whose immune defenses were already strained. For high-risk surgeries, hospitals now routinely apply antiseptic nasal treatments and antimicrobial body washes before the procedure to reduce the staph bacteria a patient is carrying.
Conditions That Raise Your Risk
Certain health conditions make staph infections more likely because they compromise either your skin barrier or your immune system’s ability to fight off bacteria once they get in. People with eczema or other chronic skin conditions are especially vulnerable. Eczema causes persistent cracks and inflammation in the skin, and research shows this barrier disruption directly increases susceptibility to bacterial infection. The relationship goes both ways: staph bacteria produce substances that further damage the skin barrier, which can trigger more eczema flares.
Diabetes reduces blood flow to the extremities and slows wound healing, giving bacteria more time to establish an infection in even minor cuts or blisters. Immune-suppressing conditions or medications, whether from an autoimmune disease, organ transplant, or cancer treatment, also lower your body’s ability to contain staph before it spreads. People who inject drugs face risk from both the needle punctures themselves and from non-sterile equipment.
Staph in Food
Staph can also make you sick through food, though this works differently from a skin infection. When someone carrying staph bacteria handles food without washing their hands, the bacteria can transfer to the food. If that food then sits at temperatures between 40°F and 140°F, the bacteria multiply and produce a toxin. It is the toxin, not the bacteria themselves, that causes illness, typically rapid-onset nausea, vomiting, and stomach cramps.
An important detail: cooking the food afterward kills the bacteria but does not destroy the toxin. Once the toxin is there, no amount of reheating will make the food safe. Foods that are handled after cooking and then not reheated, like sliced deli meats, sandwiches, pastries, and puddings, carry the highest risk. This type of food poisoning usually resolves on its own within a day or two.
Practical Ways to Reduce Exposure
Most staph infections start with a combination of two things: bacteria on a surface or another person’s skin, and a break in your own skin that lets them in. Addressing either side of that equation lowers your risk substantially.
- Clean wounds promptly. Washing cuts, scrapes, and abrasions with soap and water and keeping them covered with a clean bandage removes bacteria before they can establish an infection.
- Don’t share personal items. Razors, towels, washcloths, and bar soap can all transfer staph between people. This applies at home and especially in shared living situations.
- Wipe down shared equipment. Gym machines, weight benches, and wrestling mats can harbor staph for weeks indoors. Cleaning them before and after use with disinfectant wipes makes a real difference.
- Wash hands before handling food. This is the single most effective step to prevent staph food poisoning, and it matters most for foods that won’t be cooked again before serving.
- Keep chronic skin conditions managed. If you have eczema or another condition that disrupts your skin barrier, consistent treatment reduces the openings available to staph bacteria.