What Is Staphylococcus Aureus, And How Can You Test For It?

Staphylococcus aureus (S. aureus), also known as Staphylococcus aureus or Staphylococcus Aureus, is a gram-positive cocci bacteria that can cause infections such as skin abscesses, pneumonia, septicemia, osteomyelitis, and bacteremia.

The organism has become resistant to multiple antibiotics over time, and so testing and identification is crucial for discovering new solutions to manage the bacteria.

What Is Staphylococcus Aureus, And How Can You Test For It?

S. aureus is a common cause of nosocomial infection. In addition, it is responsible for community-acquired infections such as food poisoning, wound infections, and urinary tract infections.

What Is Staphylococcus Aureus?

Staphylococcus aureus is a gram-positive coccus bacterium that belongs to the family Staphylococcaceae.

It is part of the normal flora of human skin and mucosal membranes, and it is often associated with minor skin lesions, as well as being one of the most common pathogens causing hospital-acquired infections, especially those involving surgical wounds; if you have heard of this bacteria, this is the most likely source.

Infections caused by S. aureus are usually treated with antibiotics. Methicillin-resistant S aureus (MRSA), however, are becoming increasingly resistant to many commonly prescribed antibiotics.

As such, MRSA has become a major public health concern, and the subject of a great deal of media attention as scientists and medics work together to find a solution and save lives.

S. aureus is also a leading cause of food poisoning. In addition, some strains of S. aureus are able to produce enterotoxins, which are substances that increase intestinal permeability, allowing toxins to pass into the bloodstream.

This may lead to nausea, vomiting, diarrhea, abdominal pain, or even death.

S. aureus is a very important pathogen in humans. It causes a wide range of diseases, including:

Skin Infection

These include impetigo, folliculitis, furunculosis, cellulitis, abscesses, boils, carbuncles, burns, and wound infections.

Bloodstream Infections

Bloodstream infections are caused by bacteria, such as S. aureus, that invade the bloodstream and circulate throughout the body.

These infections are life-threatening and require immediate medical attention.

They are almost always associated with surgical procedures, catheters, intravenous drug abuse, or other invasive medical techniques, and will need urgent treatment.

Common examples of bloodstream infections include septicemia, endocarditis, osteomyelitis, arthritis, pneumonia, meningitis, bacteremia, and mastoiditis.

Respiratory Tract Infections

Bacterial infections of the respiratory tract are one of the leading causes of illness and death worldwide.

In fact, many of the most common illnesses—such as colds, influenza, bronchitis, pneumonia, tuberculosis, and lung cancer—are caused by respiratory pathogens.

These diseases affect millions of Americans every year, causing billions of dollars in health care costs.

Common examples include bronchitis, tracheobronchitis, sinusitis, otitis media, and peritonsillar abscesses.

Urinary Tract Infection

UTIs are very common in women, particularly those who have recently given birth, and these include cystitis, urethritis, prostatitis, epididymitis, and pyelonephritis.

They also occur frequently in young children, older adults, diabetics, and patients with other medical problems such as kidney disease.

UTIs are caused by bacteria that enter the urinary system through the vagina or anus. Once inside the body, the bacteria travel up into the bladder where they begin to multiply.

If left untreated, UTIs may lead to serious complications including kidney damage, loss of function, and even death.

Gastrointestinal Tract Infection

These infections are less common than conditions such as skin infections but still occur frequently enough to warrant discussion – especially as S. aureus is a very common cause of this type of infection.

Gastrointestinal tract infections are caused by bacteria that invade the digestive tract. They are typically associated with diarrhea, vomiting, stomach cramps, nausea, and fever.

These symptoms may also indicate other illnesses, so it’s important to consult a physician before taking any action.

They include gastroenteritis, colitis, cholecystitis, cholangitis, diverticulitis, ileitis, appendicitis, and peritonitis.

As you can see, the presence of S. aureus can be extremely dangerous for humans, and the ability to identify and test for this bacteria is, therefore, crucial to ensure that we protect ourselves against its harmful effects.

How Can Staphylococcus Aureus Be Identified?

How Can Staphylococcus Aureus Be Identified?

There are two main methods to identify S. aureus. One method involves culturing the bacteria from clinical specimens. This method takes several days to complete.

Another method involves using biochemical tests. These tests take less time to perform, but they cannot differentiate between methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus(MSSA).

Some of the main tests that you can use to identify the presence of Staph include:

Gram Stain

Staphylococcus Aureus can be identified using the Gram stain method, and this involves staining the bacteria with crystal violet dye.

After the sample is stained, a microscope will be used to view the bacteria under a high-power magnification. If there are no other bacteria present in the specimen, then the bacteria will appear purple.

However, if there are other bacteria present, then they will appear blue.

Phenol-Sulfonphthalein Test

The phenol-sulfonphthalein test is an alternative to the Gram stain method. It involves adding a solution containing sodium nitrite and potassium ferricyanide to the culture medium.

The reaction results in the formation of red-colored products which indicate the presence of S. aureus in the sample.


The culture method involves growing the bacteria on nutrient agar plates. Once the bacteria have been grown, they are incubated at 37° C for 24 to 48 hours. A colony of S. aureus appears as a small white spot surrounded by a clear zone.

Vitek 2 System

This system uses a colorimetric assay to detect the production of a substance known as beta hemolysin.

Beta hemolysin is produced by S. aureus and is found in blood samples taken from patients who have suffered from S. aureus infections. The Vitek 2 System uses a card reader to determine the presence of beta hemolysin in the sample.

Molecular Methods

These methods involve identifying specific genes within the genome of the bacteria. They are useful when isolating MRSA strains because they allow for rapid detection of methicillin resistance.

Final Thoughts

Staphylococcus aureus is a bacteria that has the potential to cause serious harm and damage, and knowing how to test for and identify it is important.

Fortunately, there are a number of tests and techniques that you can employ, allowing scientists to understand s. aureus and take the steps to create new medical innovations and solutions.

Jennifer Dawkins

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