Staphylococcus aureus: what it is and how to treat it

It is a very common bacterium, often harmless, but can cause various infections. Hygiene, attention and appropriate care are the best strategy to effectively manage the majority of cases, reducing risks and complications

Marta and Luca are the parents of Flavia, 11 years old. After some recurring pimples on the skin, the pediatrician speaks of “staphylococcus”. The word scares them: is it contagious? Is it serious? And, above all, can it be cured?

Staphylococcus is a very common, often harmless bacterium that normally lives on our skin and in the mucous membranes. Only in some circumstances can it become the cause of infection. Knowing it better helps reduce unfounded fears and correctly manage situations in which treatment is really needed.

What is staphylococcus

Staphylococci are Gram-positive bacteria with a rounded shape, arranged in clusters (hence the name, from the Greek staphyle“grape”). There are many species, some of which coexist peacefully with us: in this case we are talking about saprophytic bacteria, that is, normally present on the skin, in the nostrils or in the intestinal tract, without causing disease.

The best known and clinically relevant species is lo Staphylococcus aureusalso called staphylococcus aureus, a coagulase positive bacterium, capable of producing an enzyme that distinguishes it from other less aggressive species. Next to him there are numerous coagulase-negative staphylococci such as S. epidermidis, S. hominis, S. capitis, S. warneri And S. lugdunensis: mostly harmless, but capable in rare cases of causing infections, especially in the presence of medical devices or fragile conditions.

It should be clarified that staphylococcus is a different bacterium than streptococcus or pneumococcus (Streptococcus pneumoniae), responsible instead for pneumonia and ear infections: these are different bacteria, even if they are both Gram-positive.

Staphylococcal infections: symptoms

Staphylococcal infections can affect different organs and tissues, but the most common in children are skin infections.

• Staphylococcal skin infection: often manifests itself with boils, impetigo (yellowish vesicles and crusts often around the mouth and nose, but also in other parts of the body, very contagious) or folliculitis, an inflammation of the hair follicles. In rare cases, staphylococcal dermatitis may occur, which worsens pre-existing eczema conditions.
• In other cases the bacterium can colonize the throat or nose, causing a sore throat, persistent stuffy nose or small local infections (pharyngitis).
• More rarely it can be found in the urine, especially in subjects with catheters or after invasive procedures.

Overall, symptoms range from mild skin lesions to deeper infections, but in most cases they resolve with targeted therapy and without complications.

Staphylococcus epidermidis

Staphylococcus epidermidis is one of the most common bacteria in the skin flora: it normally lives on the skin and is usually harmless. It belongs to the group of coagulase-negative staphylococci, so it is less aggressive than Staphylococcus aureus, but can become pathogenic in some circumstances.

When defenses are reduced or medical devices such as catheters, prostheses or shunts are present, it can cause opportunistic infections (i.e. infections caused by bacteria, viruses, fungi or protozoa in subjects with compromised immune systems; the same pathogens, under normal immune conditions, do not cause disease), especially in a hospital environment. In these cases the bacterium forms a biofilm that protects it from antibiotics and the immune system.

In hospitalized infants and children, S. epidermidis can cause catheter-related infections or, more rarely, sepsis (an acute condition due to an excessive inflammatory response of the entire body to an infection). In healthy children, however, it rarely causes problems.
Treatment involves removal of the infected device and use of targeted antibiotics.

In summary, it is a common skin microbe that can only turn into a pathogen under particular conditions.

Staphylococcus in pregnancy

During pregnancy, it Staphylococcus aureus it can be present on the skin or in the mucous membranes (especially of the nose and throat) without causing symptoms: in this case we speak of healthy carriers. In most cases it does not pose any risks, but in some situations it can cause skin infections, mastitis or, more rarely, systemic infections, which must be treated with antibiotics compatible with pregnancy.

In newborns and young children, staphylococcus can instead cause more varied manifestations. The most common are skin infections, such as impetigo, folliculitis or staphylococcal dermatitis. In more severe cases, especially in newborns, it can cause staphylococcal scalded skin syndrome (staphylococcal scalded skin syndrome), characterized by fever, redness and peeling of the skin.

In the presence of persistent fever, extensive skin lesions or signs of deep infection, it is important to promptly contact your pediatrician to establish a correct diagnosis and start adequate treatment.

How is staphylococcus caught?

Staphylococcus is a widespread bacterium in the environment and can be found on the skin, nasal mucosa and throat of many healthy people, without causing disease. Transmission occurs mainly through direct contact with infected skin lesions or, more rarely, through contaminated objects such as towels, sheets or medical instruments.

For this reason, staphylococcus is considered moderately contagious, especially in closed communities (schools, gyms, hospital wards). However, the simple presence of the bacterium is not enough to cause an infection: predisposing conditions are also needed, such as small wounds, irritated skin or a weakened immune system.

Staphylococcus aureus, in particular, can colonize the nose and throat, becoming a possible source of self-infection: by touching the face or nose and then the skin, the bacterium can pass from one point of the body to another.

Good hand hygiene and the use of non-shared personal objects remain the most effective measures to prevent the spread of the bacterium.

Diagnosis of staphylococcus

The diagnosis of staphylococcal infection is always based on clinical evaluation – type of lesion, symptoms and site of infection – associated, if necessary, with targeted microbiological tests.

The most common test is the swab, which can be skin, nasal or throat, depending on the symptoms. In the presence of skin lesions, the skin swab allows you to identify the responsible bacterium and evaluate its sensitivity to antibiotics via an antibiogram.

In the case of deeper infections (such as osteomyelitis, septic arthritis, or sepsis), blood, urine, or body fluid tests may be necessary to isolate the organism.

It is important to remember that being a carrier of staphylococcus, for example in the nose or on the skin, does not mean being ill: therapy should only be reserved for cases in which the bacterium causes symptoms or active infection.

How is staphylococcus treated?

Treatment of staph infection depends on the type of infection, location, and the patient’s condition.

In mild skin forms, such as small folliculitis or impetigo, topical therapy with local disinfectants or antibiotics (for example mupirocin-based) is often sufficient, always on medical indication.

More extensive or deep infections require oral or intravenous antibiotics. The choice of drug is based on the antibiogram (a test that determines the sensitivity of a microorganism to different antibiotics and helps choose the most effective therapy), since some variants – such as methicillin-resistant Staphylococcus aureus (MRSA) – do not respond to common β-lactam antibiotics.

Some natural remedies can have a supporting role in mild skin infections: for example baths or washing with saline solution, creams based on aloe vera or other soothing products that help reduce inflammation and promote healing of the skin. They do not replace antibiotics and should always be used under medical supervision.

Prevention

Prevention of staphylococcal infections is based above all on good hygiene practices and attention to risk factors.

Key measures include:

• Hand hygiene, i.e. frequent washing with soap and water or use of alcoholic solutions, especially before meals and after touching wounds or potentially contaminated objects.
• Avoid sharing personal items, such as towels, sheets, combs or underwear, which can transmit the bacteria.
• Wound care. Cuts or abrasions should be cleaned, disinfected and covered until completely healed.
• Cleaning of environments. Commonly used surfaces and objects must be regularly cleaned and disinfected, especially in community or hospital environments.
• Colonization control. In children with recurrent infections, the doctor may evaluate nasal or skin decolonization with specific products.

In hospitalized infants and children, it is especially important to follow staff and environmental hygiene protocols to prevent infections with staphylococcus aureus or other coagulase-negative staphylococci.

With these simple precautions it is possible to significantly reduce the risk of infections, protecting children’s health without resorting to preventive antibiotic treatments, which are not indicated in the absence of active infection.

Complications and consequences

In most healthy children, staph infections are mild and localized, such as small skin lesions or folliculitis. However, in some cases the bacterium can cause more serious complications, especially if not treated correctly or if it affects children with reduced immune defenses.

Among the possible consequences we find:

• Staphylococcus in the blood (bacteremia). The bacterium can enter the circulation and cause systemic infections.
• Staphylococcal sepsis. A severe inflammatory response requiring urgent hospital management.
• Staphylococcal scalded skin syndrome. Rarer, typical in newborns and young children, characterized by fever, widespread redness and detachment of the superficial skin.
• Osteomyelitis and septic arthritis. Bone or joint infections, typically in older children, requiring hospitalization and targeted antibiotic therapy.

These complications, while rare, highlight the importance of timely diagnosis and appropriate treatment to prevent a simple skin infection from evolving into a more serious condition.

Scientific research and recent studies

Protein A is one of the most studied characteristics of Staphylococcus aureus. It is a molecule that the bacterium produces to protect itself from the immune system: it binds to antibodies in order to make it more difficult for the body to recognize and attack it. Thanks to this strategy, the bacterium can last longer in the body and cause more persistent infections.

Recent studies have also highlighted that protein A contributes to the formation of biofilms, i.e. adhesive structures that allow the bacterium to attach firmly to skin, mucous membranes or medical devices. These biofilms make infections more difficult to treat and increase the risk of recurrence.

Understanding the role of protein A is important because it allows researchers to develop new drugs and vaccines aimed at neutralizing this bacterium’s defense mechanism, paving the way for more effective therapies against S. aureus infections.

In conclusion, understanding staph and its defense mechanisms, such as protein A, helps prevent, recognize and treat infections promptly. With hygiene, attention and appropriate care, most infections in children can be managed effectively, reducing risks and complications.