What is Staphylococcus aureus Infection?
Staphylococcus aureus is a major bacterial germ that affects humans, causing a wide range of health problems. These infections can occur in both community settings and hospitals, and they can be difficult to treat because some strains, like MRSA (Methicillin-Resistant Staphylococcus aureus), have become resistant to multiple drugs.
Staphylococcus aureus is present in our environment and even on our own bodies, often living harmlessly on our skin and in our nasal passageways. Normally, it doesn’t cause any problems on healthy skin. However, if Staphylococcus aureus enters into our blood or other parts of our body, it can potentially cause serious infections.
The bacteria is typically spread through direct contact with a person who has the infection. However, it can also spread in different ways in some cases.
What Causes Staphylococcus aureus Infection?
Staphylococcus aureus is a type of bacteria that has a purple color when tested and is round in shape, often arranged in clusters similar to grapes. It can grow in salty environments and is often golden or yellow in color. This bacteria can live with or without oxygen, and it survives in temperatures between 18 C and 40 C. It’s recognized by certain chemical reactions such as being catalase and coagulase positive, which differentiates it from other bacteria, and sensitive to the antibiotic novobiocin which distinguishes it from another Staphylococcus species called Staphylococcus saprophyticus.
Some strains of Staphylococcus aureus carry a gene known as the ‘mec’ gene, causing them to be resistant to several antibiotics. This mec gene is part of a larger region of the bacterial chromosome that varies between different strains. This gene makes a protein called PBP-2a, which is crucial for the bacteria to build its cell wall. This protein is unique because, unlike other proteins, it doesn’t easily bind with antibiotics derived from penicillin. This means that these strains of the bacteria continue growing even when many antibiotics are present, leading them to be resistant to these drugs. These strains are known as MRSA, and they’re known to resist drugs like methicillin, nafcillin, oxacillin, and cephalosporins.
Risk Factors and Frequency for Staphylococcus aureus Infection
Staphylococcus aureus, which includes drug-resistant strains like MRSA, are bacteria that can be found on the skin and in mucous membranes. Humans are their main nesting spot. It’s thought that up to half of all adults carry these bacteria without showing any symptoms, and around 15% of people always have S. aureus in their noses. Certain groups have a higher chance of carrying these bacteria, as much as 80%. These include health care workers, people who inject medications or drugs (like diabetics and people who use drugs intravenously), patients in the hospital, and people with weakened immune systems. S. aureus bacteria can be passed from person to person through direct touch or by coming into contact with contaminated items.
Signs and Symptoms of Staphylococcus aureus Infection
Getting a complete understanding of a patient’s history and a detailed physical examination is crucial for correctly diagnosing and treating an infection. Please note that the specific details can vary widely depending on the type of infection.
Testing for Staphylococcus aureus Infection
To check for a S. aureus infection, doctors usually focus on the signs and symptoms of the infection and a person’s medical history and physical examination outcomes. In a lot of situations, conducting simple tests on samples, like blood or mucus, is enough to identify the infection. However, sometimes a more specialized test, known as RT-PCR for 16S rRNA genes, might be necessary.
It’s often essential to perform a drug susceptibility test too. This helps determine which medicines would be most effective in treating the infection. If tests are conducted on samples taken from a patient for detection of S. aureus in the lab, it’s important to remember that their presence doesn’t always mean an infection is present. This is because S. aureus can actually be a part of the normal flora, or the micro-organisms that naturally live on our skin and mucous membranes.
Treatment Options for Staphylococcus aureus Infection
The proper treatment for S. aureus infections, a type of bacteria that can cause a range of diseases, depends on the specific type of infection, as well as whether the bacteria are resistant to certain drugs. If needed, medication to kill or inhibit the bacteria is typically used, but the length and method of treatment will vary due to factors such as the infection type.
In many cases, penicillin, a common antibiotic, is the preferred choice if the infection is caused by a strain of S. aureus that is sensitive to methicillin (this is referred to as a MSSA or methicillin-sensitive S. aureus strain). For S. aureus infections that are resistant to methicillin (known as MRSA strains), the antibiotic vancomycin is often used.
In some situations, additional treatments may be necessary along with antibiotics. For instance, if the illness is brought about by toxins, fluid-replacement treatments may be needed. In cases where an infection involves a foreign device like a prosthetic heart valve or catheter, it might be necessary to remove the device.
Because many MRSA bacteria have become resistant to multiple antibiotics, infections caused by these strains are becoming increasingly severe and common in both hospitals and communities.
What else can Staphylococcus aureus Infection be?
There are several medical conditions that can occur in children and adults alike. These include:
- Bacteremia (Bacteria in the blood)
- Chemical Burns
- Impetigo (a common skin infection)
- Juvenile Idiopathic Arthritis (a type of arthritis that affects children)
- Kawasaki Disease (a rare condition in children that causes inflammation in blood vessels)
- Leptospirosis (a bacterial disease)
- Parvovirus B19 Infection (a viral infection)
- Pediatric Bacterial Endocarditis (an infection of the heart’s inner lining in children)
- IBS or Irritable Bowel Syndrome
- Pediatric Osteomyelitis (a bone infection in children)
- Pediatric Serum Sickness (an immune complex-mediated hypersensitivity reaction in children)
