January 29, 2011

Staphilococcus: The good, the bad and the ugly

By Sola Ogundipe

Morayo had never heard of the resistant bacteria infection called “staph” as it is commonly known, until her three-year-old daughter, Enitan who had been sick much more often than any of her siblings was diagnosed of the infection.

It seemed like as soon as she finished one course of antibiotics, she got sick again and went on another course. But it was not until after two weeks of incisive tests showed resistant bacteria infection that she found out the reason why her daughter wasn’t getting better.

Only then did Morayo discover the void of information available about this bacterial infection.
She spoke to the Ear, Nose & Throat (ENT) doctor, the infectious disease specialist, and the paediatrician. They all had the same story to tell about the infections and their unusual characteristics.


For the majority of diseases caused by S. aureus, experts say it is difficult to determine precisely the role of any given factor. However, there are correlations between strains isolated from particular diseases and expression of particular virulence determinants, which suggests their role in a particular diseases.

Human staphylococcal infections are frequent, but usually remain localized such as a hair follicle, but usually it is a break in the skin which may be a minute needle-stick or a surgical wound. Foreign bodies, including sutures, are readily colonized by staphylococci, which may make infections difficult to control. Another portal of entry is the respiratory tract.

Only recently, findings showed that there were rising concerns about the staph superbug within the local hospital community. For years, the incidence of staph, has been a sore point in Nigeria.

Staphylococcus is a group of bacteria that can cause a multitude of diseases as a result of infection of various tissues of the body. Staphylococcus is more familiarly known as “Staph.” Staph-related illness can range from mild and requiring no treatment to severe and potentially fatal Statistics say there are over 30 different types of staphylococci infecting humans, but most infections are caused by the Staphylococcus aureus. Staphylococci can be found normally in the nose and on the skin (and less commonly in other locations) of 25%-30% of healthy adults. In the majority of cases, the bacteria do not cause disease. However, damage to the skin or other injury may allow the bacteria to overcome the natural protective mechanisms of the body, leading to infection.

Who is at risk?

Anyone can develop a Staph infection, although certain groups of people are at greater risk, including newborn infants, breast feeding women, and people with chronic conditions such as diabetes, cancer, vascular disease, and lung disease. Injecting drug users, those with skin injuries or disorders, intravenous catheters, surgical incisions, and those with a weakened immune system all have an increased risk of developing Staph infections.
Symptoms and signs
Staphylococcal disease of the skin usually results in a localized collection of pus, known as an abscess, boil, or furuncle. The affected area may be red, swollen, and painful. Drainage or pus is common. When Staph is in the blood (bacteremia or sepsis) it can cause high fevers, chills, and low blood pressure. Skin infections are the most common type of disease produced by Staphylococcus. Staph infections of the skin can progress to impetigo (a crusting of the skin) or cellulitis (inflammation of the connective tissue under the skin, leading to swelling and redness of the area). In rare cases, a serious complication known as scalded skin syndrome can develop. In breastfeeding women, Staph can result in mastitis (inflammation of the breast) or in abscess of the breast.

Spread of the organisms to the bloodstream is known as bacteremia or sepsis. Staphylococcal pneumonia predominantly affects people with underlying lung disease and can lead to abscess formation within the lungs. Infection of the heart valves (endocarditis) can lead to heart failure. Spread of Staphylococci to the bones can result in severe inflammation of the bones known as osteomyelitis. When Staph bacteria are present in the blood, a condition known as Staphylococcal sepsis (widespread infection of the bloodstream) or Staphylococcal bacteremia exists. Staphylococcal sepsis is a leading cause of shock and circulatory collapse, leading to death, in people with severe burns over large areas of the body. When untreated, Staph aureus sepsis carries a mortality (death) rate of over 80 percent.

Staphylococcal infections should be contagious and can be transmitted from person to person. Pus from infected wounds may contain the bacteria, proper hygiene and handwashing is required when caring for Staph-infected wounds.

Staphylococcal food poisoning is an illness of the bowels that causes nausea, vomiting, diarrhea, and dehydration. It is caused by eating foods contaminated with toxins produced by Staphylococcus aureus. Symptoms usually develop within one to six hours after eating contaminated food. The illness usually lasts for one to three days and resolves on its own. Patients with this illness are not contagious, since toxins are not transmitted from one person to another.

Toxic shock syndrome is an illness caused by toxins secreted by Staph aureus bacteria growing under conditions in which there is little or no oxygen.

In cases of minor skin infections, Staphylococcal infections are commonly diagnosed by their appearance without the need for laboratory testing. More serious staphylococcal infections such as infection of the bloodstream, pneumonia, and endocarditis require culturing of samples of blood or infected fluids. The laboratory establishes the diagnosis and performs special tests to determine which antibiotics are effective against the bacteria.


Minor skin infections are usually treated with an antibiotic ointment such as a nonprescription triple-antibiotic mixture. In some cases, oral antibiotics may be given for skin infections. Additionally, if abscesses are present, they are surgically drained. More serious and life-threatening infections are treated with intravenous antibiotics. The choice of antibiotic depends on the susceptibility of the particular staphylococcal strain as determined by culture results in the laboratory. Some Staph strains, such as MRSA (see next section), are resistant to many antibiotics.

Persons at most risk

* Staph carriers (many individuals who carry Staphylococcus aureus in the nose, throat or skin; 20-30 per cent of people are colonized persistently, especially health care workers, patients with diabetes and those on dialysis)
* Newborn infants
* Breastfeeding women
* Obese persons
* People living in crowded communities or hot climates
* Those with skin injuries or surgical wounds
* Persons with piercings, fresh tatoos, and skin diseases, like atopic dermatitis
* Persons with weak immune system, diabetes, cancer, vascular, blood or lung disease
* Patients receiving oral steroids or chemotherapy

Are Staph infections contagious?
Staph skin infections are contagious. They can spread by:
* Skin to skin contact with infected person
* Sharing razors, towels, clothes, bed linens, sport equipment (athletes!), toys
* Walking barefoot or sitting around swimming pools
* Contact with infected pets

* Auto-infection by nose picking and skin scratching
* Sneezing – when droplets from the nose of infected person (or staph carrier) fall on an injured skin of another person


Scalded skin syndrome is a potentially serious side effect of infection with Staph bacteria that produce a specific protein which loosens the “cement” holding the various layers of the skin together. This allows blister formation and sloughing of the top layer of skin. If it occurs over large body regions, it can be deadly, similar to a large surface area of the body having been burned. It is necessary to treat scalded skin syndrome with intravenous antibiotics and to protect the skin from allowing dehydration to occur if large areas peel off.

The disease occurs predominantly in children but can occur in anyone. It is known formally as Staphylococcal scalded skin syndrome.


No vaccine is available against Staphylococcus aureus. Since the bacteria are so widespread and cause so many different diseases, prevention of Staph infections requires attention to the risk factors that may increase the likelihood of getting a particular type of Staph infection. For example, it is possible for menstruating women reduce the risk of toxic shock syndrome by frequently changing tampons (at least every four to eight hours), using low-absorbency tampons, and alternating sanitary pad and tampon use. Careful attention to food-handling and food-preparation practices can decrease the risk of Staphylococcal food poisoning.

Prevention of Staph infections can be aided by proper hygiene when caring for skin wounds. Careful hand washing, avoiding close skin contact with possible infected individuals, and proper hygienic care of skin scrapes, cuts, and wounds can all reduce the likelihood of skin infections due to Staph.

Staph infection at a glance

* Staphylococcus is group of bacteria that can cause a multitude of diseases.
* Staph infections may cause disease due to direct infection or due to the production of toxins by the bacteria.
* Boils, impetigo, food poisoning, cellulitis, and toxic shock syndrome are all examples of diseases that may be caused by Staphylococcus.
* Methicillin-resistant Staphylococcus aureus, known as MRSA, is a type of Staphylococcus aureus that is resistant to the antibiotic methicillin and other drugs in this class.
* Staph infections are treated with topical, oral, or intravenous antibiotics, depending upon the type of infection.