Tag Archives: Skin Infections

Dr. C’s Journal: MRSA- Methicillin Resistant Staphylococcus Aureus

Staphylococcus aureus is a highly successful – eg.BAD – disease producing bacterium, or “pathogen”. From the standpoint of the bacterium, it didn’t know it was so bad, and was merely producing factors that break down its surroundings to produce food for multiplication. Unfortunately, the proteins-ENZYMES- produced by the staphylococcus, In its effort to survive, can cause anything from diarrhea, abscesses, high fevers, shock, and kidney failure to death.

The staphylococcus was very successful for thousands of years, until slowed down by penicillin.

Penicillin attached itself to a critical part of the staphylococcal cell wall, which stopped the bacterium from functioning. The staphylococcus retaliated by producing an enzyme, penicillinase, that destroys penicillin. Humans responded by producing methicillin, which resisted destruction by the penicillinase. The Staph responded again by a genetic change in the target of penicillin, PBP, so that the Methicillin wouldn’t attach, hence the term methicillin resistant staphylococcus aureus, MRSA.

Interestingly, the MRSA can send little packets of genes called “plasmids” to other bacteria, even other species, which take in the packets and allow them to resist methecillin also. This is called horizontal transfer of resistance.

The staphylococcus aureus has many other ways of protecting itself, and is a good example of the various ways a bacterium can deal with antibiotics.

It can prevent the antibiotic from gaining entrance, or pump it out of the cell faster. It can destroy the antibiotic, as with penicillinase. It can modify the bacterial target of the antibiotic, as in the PBP that protects from penicillin. It can also develop an alternative metabolic pathway or structure to bypass the effect of the antibiotic.

THIS IS WAR, similar to the human kind. The offense develops the sword. The defense develops the shield. The offense develops mounted archery. The defense develops the castle and so on.

We’re not so very different from the bacteria, and in fact every single cell of our bodies has descended from an ancestral  bacterial cell that engulfed another bacterium, which became the mitochondrion, a “slave cell” dedicated to producing thousands of times more energy than the simple bacterium, and leading to multicellular organisms.

Each organism develops appropriate defenses. Penicillium molds developed penicillin to protect themselves from bacteria and we took advantage of this. But it is a dynamic process, with both offense and defense having to adapt repeatedly over time.

In the next article, I will be discussing the bacterium Pseudomonas aeruginosa which is not as dynamic as the staph aureus; It specializes in people with problems, and is called a “facultative pathogen”.

However Pseudomonas is particularly good at exploiting its specialized habitat, which is increasing with the popularity of immunosuppressants and insertion of surgical hardware.

—Dr. C.

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Swelling of the ankles becomes increasingly common as you get older. This swelling can be caused by thrombophlebitis, or skin infections which have been discussed in previous articles. Otherwise it is usually part of a condition called edema.

Edema is commonly caused by problems in the cardiovascular system, kidneys, or liver. Edema can occur in the face and abdominal cavity or elsewhere, But because of gravity and the fact that we are  usually upright-on our feet, it is usually is most prominent in the legs, especially the ankles. Edema can be caused by a normal pregnancy. The developing baby puts quite a strain on the heart and circulatory system.

Chronic accumulation of fluid in the tissues usually occurs because of heart and blood vessel problems, liver disease (albumin lack), diet (excess salt intake), kidney disease (deficient salt excretion), vein problems (valve malfunction), and lymphatic problems (surgical lymph node excision).

Obesity contributes by impacting the heart and liver primarily. Proper sleep, diet and exercise help in most of these areas, and edema is rare in healthy people.

I have always considered sugar(obesity, cardiovascular effects) and salt(hypertension, cardiovascular and  kidney load) as poisonous. I discovered the valve incompetence in the veins of my left leg because it became more blue than my right leg. With good exercise, sleep, diet program and compression stockings, edema never occurred.

The swelling and stretched shiny skin in the ankles that I see in many of my overweight friends makes a tempting target for germs of all kinds. and small skin sores often follow.

If you developed swelling in your ankles or other areas, it’s best to check with your doctor to get an explanation.

—Dr. C.


The skin is the protective barrier between the inside of our bodies and the outside world of microorganisms, parasites and toxins. It is often the site of inflammation and infections.

In past times, before the advent of cleanliness and antibiotics, mankind was plagued by erysipelas, boils, carbuncles, and other severe infections of the skin, which are rarely seen now. The beta hemolytic streptococcus and Staphylococcus aureus were ubiquitous in the past, and mostly are contained today.

Severe Infections presently require some skin abnormality, immune deficiency, neglect, animal bite or other breach of skin integrity to be a problem. Antibiotic resistance, however, is allowing some organisms like MERSA to make a comeback.

ECZEMA. or Atopic Dermatitis, was common in my medical practice. This condition weakens the skin barrier, allowing Staphylococcal infection to gain a foothold. In my day, If there were a flare of eczema severity, antibiotics would often help. Leg edema and swelling. such as from heart failure, especially coupled with diabetes and blood vessel disease is also an invitation to infection, such as cellulitis.

Redness, swelling, warmth and pain- the classic rubor, tumor, calor and dolor- as well as swollen local lymph nodes and fever often betray infection of the skin. Please see the recently posted infographic on celulitis.

IMMUNE DEFICIENCY raises the likelihood and risk of severe skin infections. Infection from “flesh-eating bacteria”, often beta hemolytic streptococci in deep tissue planes , is a medical emergency. Immediate surgery is often needed.

Disproportionate PAIN after injury or surgery is often a clue. Certain age groups have characteristic skin infections, such as the scalded skin syndrome of infants, and the acne of adolescents. Viruses, molds, and arthropods can also infect the skin.

Viruses, such as herpes in particular can simulate bacterial infection. Ringworm from fungi is easy to distinguish, but arthropod bites, and especially bee sting can look very much like bacterial infection. Scabies and mite infestation are so itchy as to be distinct.

Topical antibiotics applied on skin breaks like cuts or breaks are useful in preventing infection. These ointments and creams are like “artificial skin”. Once again, prevention is key.

–Dr. C.