Staph Infection: Symptoms, Causes, MRSA, Treatment and Prevention

Staph infections are caused by bacteria belonging to the Staphylococcus group.

There are many types of Staphylococcus bacteria, but Staphylococcus aureus (S. aureus) is responsible for many important human infections.

Staph bacteria commonly live on people's skin and in the nose without causing illness. According to the Centers for Disease Control and Prevention (CDC), approximately 30% of people carry S. aureus in their nose.

Carrying the bacteria does not necessarily mean you have an infection.

Problems can develop when the bacteria enter damaged skin or deeper tissues.

Staph infections range from relatively minor skin infections to potentially life-threatening infections involving the bloodstream, lungs, heart, bones and other parts of the body.

What Is Staphylococcus aureus?

Staphylococcus aureus is a type of bacterium that can live harmlessly on the body.

When someone carries the bacteria without having symptoms or illness, this is called colonisation or being a carrier.

The bacteria can sometimes enter the body through:

• cuts,
• scrapes,
• surgical wounds,
• burns,
• injections,
• catheters,
• or other breaks in the skin.

Once an infection develops, its severity depends partly on where the bacteria have spread and the person's overall health.

Is Carrying Staph the Same as Having an Infection?

No.

This distinction is important.

Colonisation means the bacteria are present on or in the body without causing disease.

Infection means the bacteria are multiplying in tissues and causing illness.

Many healthy people carry staph without knowing it.

Colonisation may sometimes increase the likelihood of infection, particularly during circumstances such as surgery or use of invasive medical devices.

What Types of Infections Can Staph Cause?

Staph can cause many different illnesses.

These include:

• boils,
• abscesses,
• impetigo,
• cellulitis,
• infected wounds,
• bloodstream infections,
• sepsis,
• pneumonia,
• bone infections,
• joint infections,
• endocarditis,
• food poisoning,
• and toxic shock syndrome.

The symptoms therefore depend heavily on which part of the body is affected.

What Does a Staph Skin Infection Look Like?

Skin infections are among the most common staph infections.

They may appear as:

• pimples,
• boils,
• abscesses,
• infected cuts,
• or swollen areas of skin.

The affected area may be:

• red or discoloured,
• swollen,
• painful,
• warm,
• tender,
• or filled with pus or other drainage.

Fever may sometimes accompany a skin infection.

Skin redness can be less obvious on darker skin tones, so warmth, swelling, pain and changes from the person's normal skin appearance are also important.

What Is a Staph Abscess?

An abscess is a collection of pus caused by infection.

It can appear as a:

• painful lump,
• swollen bump,
• boil,
• or pus-filled area beneath the skin.

Staph bacteria are a common cause of skin abscesses.

Some abscesses require professional drainage.

Do not squeeze, puncture or attempt to drain a suspected staph abscess yourself.

Doing so can spread bacteria to surrounding tissues or deeper into the body.

What Is Cellulitis?

Cellulitis is an infection of deeper layers of the skin and underlying tissues.

Staph bacteria are among the organisms that can cause it.

Symptoms may include:

• redness or skin discolouration,
• warmth,
• swelling,
• tenderness,
• and pain.

The affected area may enlarge as the infection spreads.

Some people also develop fever or feel generally unwell.

Rapidly spreading redness or swelling, particularly with fever or severe illness, requires prompt medical assessment.

How Does Staph Spread?

Staph can spread through direct contact with an infected person or contaminated material.

Transmission may occur through:

• skin-to-skin contact,
• contact with infected wounds or drainage,
• shared towels,
• shared razors,
• shared clothing,
• contaminated sporting equipment,
• and contaminated surfaces.

The bacteria may survive on some surfaces for extended periods.

A break in the skin can provide an entry point for infection.

Can You Get Staph From Sharing Towels or Razors?

Yes.

Personal items that contact the skin can become contaminated.

For this reason, avoid sharing:

• towels,
• washcloths,
• razors,
• clothing that directly contacts infected skin,
• and other personal items

with someone who has an active staph or MRSA skin infection.

Shared sports equipment should also be appropriately cleaned and dried.

What Is MRSA?

MRSA stands for methicillin-resistant Staphylococcus aureus.

It is a type of S. aureus that has developed resistance to several antibiotics.

MRSA can cause many of the same infections as other forms of S. aureus.

The important difference is that some antibiotics normally used against staph will not work against MRSA.

Is MRSA a Different Disease From Staph?

No.

MRSA is a type of Staphylococcus aureus.

Other S. aureus bacteria remain susceptible to methicillin-related antibiotics and are sometimes called MSSA — methicillin-susceptible Staphylococcus aureus.

Both resistant and susceptible staph can cause serious disease.

Antibiotic resistance does not mean MRSA always causes a more severe infection; it means treatment choices are more limited because certain antibiotics will not kill the bacteria.

Can You Tell MRSA by Looking at a Wound?

No.

You cannot reliably determine whether a skin infection is MRSA simply by looking at it.

MRSA skin infections may resemble:

• boils,
• pimples,
• abscesses,
• infected cuts,
• or other skin infections.

Laboratory testing of an appropriate clinical sample may be needed to identify the bacteria and determine antibiotic susceptibility.

Who Is at Increased Risk of Staph Infection?

Anyone can develop a staph infection.

However, risk can be higher among people who:

• have diabetes,
• have cancer,
• have vascular disease,
• have eczema or other damaged skin,
• have a weakened immune system,
• receive chemotherapy,
• undergo dialysis,
• have recently had surgery,
• are hospitalized,
• have burns,
• use catheters or other invasive medical devices,
• have artificial joints, heart valves or other implanted devices,
• inject drugs,
• or participate in activities involving frequent skin-to-skin contact.

Risk factors vary according to the type of infection.

Staph Infections in Hospitals

Staph infections can occur both in communities and healthcare facilities.

Hospital patients may be particularly vulnerable because they may have:

• surgical wounds,
• intravenous lines,
• urinary catheters,
• breathing tubes,
• implanted devices,
• or weakened immune systems.

Healthcare facilities use infection-control measures such as:

• hand hygiene,
• environmental cleaning,
• appropriate use of protective equipment,
• careful management of medical devices,
• and specific precautions for resistant organisms.

Staph and Diabetes

People with diabetes can have an increased risk of certain infections.

Persistently high blood glucose can affect:

• immune function,
• circulation,
• nerve function,
• and wound healing.

A foot wound can be particularly serious when someone has diabetes.

People with diabetes should seek appropriate medical care for wounds that become:

• red or discoloured,
• swollen,
• warm,
• painful,
• draining,
• or slow to heal.

Staph and Weakened Immunity

People with weakened immune systems may be more vulnerable to serious staph infections.

This can include people receiving:

• chemotherapy,
• immune-suppressing medicines,
• treatment following organ transplantation,
• or treatment for certain immune disorders.

People living with advanced or poorly controlled HIV may also be at increased risk of some infections.

The modern approach is to describe the person's immune status and clinical circumstances rather than treating everyone living with HIV as though they have the same infection risk.

What Is a Staph Bloodstream Infection?

Staph bacteria can sometimes enter the bloodstream.

This is known as bacteraemia.

A bloodstream infection can spread bacteria to other parts of the body and can lead to severe complications such as:

• sepsis,
• endocarditis,
• bone infection,
• joint infection,
• and infection of implanted medical devices.

Bloodstream infections require urgent medical treatment.

What Is Sepsis?

Sepsis is the body's extreme and potentially life-threatening response to an infection.

Staph infections are among the infections that can cause sepsis.

Warning signs can include:

• confusion,
• difficulty breathing,
• very rapid breathing,
• severe weakness,
• fever or unusually low temperature,
• rapid heart rate,
• clammy or mottled skin,
• and reduced urine production.

Sepsis is a medical emergency.

Seek urgent medical care if it is suspected.

Can Staph Infect the Heart?

Yes.

Staph can cause infective endocarditis, an infection involving the inner lining of the heart and particularly the heart valves.

Symptoms can include:

• fever,
• chills,
• fatigue,
• shortness of breath,
• rapid heartbeat,
• and other signs of systemic illness.

Endocarditis is a serious condition requiring medical treatment, usually with intravenous antibiotics and sometimes surgery.

Can Staph Cause Pneumonia?

Yes.

S. aureus can cause pneumonia.

Symptoms may include:

• fever,
• chills,
• cough,
• chest pain,
• and difficulty breathing.

Some staph pneumonias can be severe, particularly in people with underlying illnesses or those receiving hospital care.

Difficulty breathing requires prompt medical assessment.

Can Staph Infect Bones?

Yes.

A bone infection is called osteomyelitis.

S. aureus is an important cause.

Symptoms can include:

• localized bone pain,
• swelling,
• warmth,
• redness or skin discolouration,
• fever,
• and chills.

Treatment may require prolonged antibiotics and, in some cases, surgery.

Can Staph Infect Joints?

Yes.

Staph bacteria can infect a joint, causing septic arthritis.

Possible symptoms include:

• sudden severe joint pain,
• swelling,
• warmth,
• redness or skin discolouration,
• difficulty moving the joint,
• and fever.

Septic arthritis can rapidly damage a joint and requires urgent medical treatment.

Can Staph Cause Food Poisoning?

Yes, but staphylococcal food poisoning works differently from a typical skin infection.

S. aureus can contaminate food and produce toxins.

If contaminated food is eaten, the toxin can cause sudden illness.

Symptoms commonly include:

• nausea,
• vomiting,
• stomach cramps,
• and diarrhoea.

Symptoms can begin relatively quickly after eating contaminated food.

Antibiotics do not treat the toxin already present in food.

Treatment generally focuses on replacing lost fluids and preventing dehydration.

How Can Staph Contaminate Food?

People carrying S. aureus on their skin or in their nose can contaminate food if appropriate food hygiene is not followed.

Food safety measures include:

• washing hands thoroughly,
• keeping food-preparation surfaces clean,
• storing foods at safe temperatures,
• avoiding food preparation for others when you have certain active infections,
• and following appropriate food-handling practices.

What Is Toxic Shock Syndrome?

Toxic shock syndrome (TSS) is a rare but potentially life-threatening illness caused by toxins produced by certain bacteria, including some strains of S. aureus.

Symptoms may include:

• sudden high fever,
• low blood pressure,
• vomiting,
• diarrhoea,
• confusion,
• muscle aches,
• and a widespread rash.

TSS can progress rapidly and cause organ failure.

It requires emergency medical treatment.

Are Tampons a Cause of Staph Infection?

The old article lists “the type of tampons used” as a general way of contracting staph.

That is misleading.

Tampons are primarily relevant to the risk of menstrual toxic shock syndrome, not ordinary staph skin infections.

Risk can be reduced by following product instructions, using the lowest absorbency needed and changing tampons at recommended intervals.

Toxic shock syndrome can also occur in people who are not menstruating.

How Are Staph Infections Diagnosed?

Diagnosis depends on the type and location of the infection.

A healthcare professional may use:

• physical examination,
• wound samples,
• blood cultures,
• tissue samples,
• nasal or throat swabs in selected circumstances,
• imaging tests,
• and other laboratory tests.

A sample can sometimes be tested to determine which antibiotics are likely to work against the bacteria.

How Are Staph Infections Treated?

Treatment depends on:

• where the infection is located,
• how severe it is,
• whether an abscess is present,
• the person's health,
• and whether the bacteria are resistant to antibiotics.

Treatment may involve:

• drainage of an abscess,
• topical treatment in selected cases,
• oral antibiotics,
• intravenous antibiotics,
• wound care,
• or surgery for certain deep infections.

Not every staph infection requires exactly the same treatment.

Do All Staph Skin Infections Need Antibiotics?

No.

Some uncomplicated abscesses may primarily require professional drainage, while others require antibiotics as well.

Other forms of infection require antibiotic treatment.

A healthcare professional should determine the appropriate treatment based on the infection and the individual patient.

Why Antibiotic Resistance Matters

Some staph bacteria have developed resistance to antibiotics.

MRSA is the best-known example.

Antimicrobial resistance makes infections more difficult to treat because medicines that previously worked may no longer be effective.

Using antibiotics unnecessarily or incorrectly can contribute to antimicrobial resistance.

Take antibiotics:

• only when appropriately prescribed,
• at the prescribed dose,
• and according to professional instructions.

Do not use leftover antibiotics or antibiotics prescribed for someone else.

Should You Pop a Staph Boil?

No.

Do not squeeze, puncture or pop a suspected boil or abscess.

Pus from an infected wound can contain staph bacteria and may spread the infection.

Instead:

• keep the area clean,
• cover draining wounds with a clean, dry dressing,
• wash your hands after touching the dressing,
• and seek professional advice when appropriate.

How Can Staph Infections Be Prevented?

You cannot prevent every staph infection, but several measures can reduce risk.

Keep Your Hands Clean

Wash your hands regularly with soap and water.

An alcohol-based hand sanitizer can be useful when soap and water are unavailable and the hands are not visibly dirty.

Hand hygiene is particularly important:

• before preparing food,
• after touching wounds,
• before and after changing dressings,
• and after contact with potentially contaminated items.

Keep Cuts and Wounds Covered

Clean cuts and scrapes appropriately.

Keep open or draining wounds covered with clean, dry bandages until healed.

Wash your hands before and after changing a dressing.

Dispose of used dressings appropriately.

Avoid Sharing Personal Items

Avoid sharing items that directly contact skin, particularly:

• razors,
• towels,
• washcloths,
• and clothing.

This is especially important when someone has an active skin infection.

Clean Shared Equipment

Shared equipment that contacts bare skin should be appropriately cleaned.

This is particularly relevant in:

• gyms,
• sports facilities,
• schools,
• healthcare settings,
• and other shared environments.

Use a barrier such as clothing or a clean towel between bare skin and shared surfaces when appropriate.

Shower After Exercise

Good personal hygiene can reduce the spread of skin bacteria.

Showering after activities involving:

• heavy sweating,
• close skin contact,
• or shared sports equipment

can be particularly useful.

Do not share towels after showering.

Can Washing Clothes Prevent Staph?

Clothes, towels and bedding contaminated with drainage from infected skin should be appropriately laundered.

Follow fabric-care instructions and dry items thoroughly.

There is no need to assume that every item belonging to someone carrying staph must be washed in extremely hot water.

The more important measures are:

• appropriate laundering,
• drying,
• hand hygiene,
• wound covering,
• and avoiding sharing contaminated personal items.

Should Everyone Carrying Staph Receive Treatment?

No.

Because many healthy people carry S. aureus without illness, routine treatment to remove the bacteria is not appropriate for everyone.

In selected circumstances, healthcare professionals may recommend decolonisation.

This can involve treatments such as:

• antiseptic skin washes,
• and medication applied inside the nose.

Decolonisation should be used according to professional guidance rather than attempted routinely at home.

When Should You See a Healthcare Professional?

Seek medical assessment for a suspected skin infection that:

• is painful,
• contains pus,
• is getting larger,
• becomes increasingly red or swollen,
• is not improving,
• repeatedly returns,
• or is accompanied by fever.

People with:

• diabetes,
• weakened immunity,
• implanted medical devices,
• recent surgery,
• or other significant health conditions

may need earlier assessment.

When Is a Staph Infection an Emergency?

Seek urgent medical care if an infection is accompanied by signs such as:

• difficulty breathing,
• confusion,
• fainting,
• severe weakness,
• rapidly worsening illness,
• rapidly spreading skin changes,
• very high or unusually low body temperature,
• severe joint pain and swelling,
• severe chest symptoms,
• or other signs suggesting sepsis or a serious invasive infection.

Toxic shock syndrome and suspected sepsis are medical emergencies.

Contact the appropriate emergency medical service where you live.

The Bottom Line

Staphylococcus bacteria commonly live harmlessly on human skin and in the nose.

Staphylococcus aureus can nevertheless cause infections when it enters damaged skin or other parts of the body.

Skin infections are common and may cause:

• painful red or discoloured bumps,
• swelling,
• warmth,
• pus,
• and abscesses.

More serious infections can involve the:

• bloodstream,
• lungs,
• heart,
• bones,
• and joints.

Staph can also cause food poisoning and toxic shock syndrome through bacterial toxins.

MRSA is a type of S. aureus resistant to several antibiotics. It cannot reliably be identified simply by looking at an infected wound.

Good hand hygiene, appropriate wound care, avoiding shared personal items and properly cleaning shared equipment can help reduce transmission.

Do not squeeze or pop suspected staph abscesses.

Seek appropriate medical care for worsening infections and urgent care for symptoms suggesting sepsis or other invasive disease.

Medical Disclaimer

This article provides general health information for an international audience and does not replace individualized diagnosis or treatment by a qualified healthcare professional. Staph infections vary greatly in severity and treatment. Do not take antibiotics without appropriate medical guidance or attempt to drain an abscess yourself. Seek urgent medical care for rapidly worsening infection, difficulty breathing, confusion, severe weakness, suspected sepsis, toxic shock syndrome or other serious symptoms.

Sources and Further Reading

Centers for Disease Control and Prevention — Staphylococcus aureus Basics

https://www.cdc.gov/staphylococcus-aureus/about/

Centers for Disease Control and Prevention — MRSA Basics

https://www.cdc.gov/mrsa/about/index.html

Centers for Disease Control and Prevention — Preventing MRSA

https://www.cdc.gov/mrsa/prevention/index.html

MedlinePlus — Staphylococcal Infections

https://medlineplus.gov/staphylococcalinfections.html

World Health Organization — Antimicrobial Resistance

https://www.who.int/health-topics/antimicrobial-resistance