All skin wounds become contaminated with bacteria. This does not mean the wound is infected but simply colonized. This is a normal feature of healing. Bacteria in chronic wounds reside in a community called a biofim. A biofilm is analogous to a squatter village. Imagine a ball of the kid’s toy called slime. In the slime example of a biofilm, skin cells stick to each other and the bacteria adhere to each other and the cells. Surrounding this complex is a soup of fluid containing two components. There is extracellular or body fluid that normally surrounds cells plus a polymeric substance, which is liquid secreted by the microorganisms. This slimy matrix or biofim allows bacteria to hide from the body’s natural defenses and treatments, there becoming resistant to prescribed antibiotics.
In acute or early wounds, harmless bacteria that are normally on our skin are in the majority. Then the bad, more dangerous bacteria invade the wound such as Staph. Aureu, better known for causing boils or abscesses, and Beta-hemolytic Streptococcus, notorious for causing strep throat. After four weeks, wounds become contaminated with organisms that grow with air, oxygen but can also survive without it. These organisms such as Proteus, E. coli, and Klebsiella usually live in the bowel and are commonly found in feces.
Sometimes these organisms can lead to an actual infection. How does one know when a wound is infected and needs an oral or intravenous antibiotic? There are specific signs and symptoms that doctors look for to determine if the wound is infected. These have been known to physicians since antiquity. Two thousand years ago Celsus, a Roman scientist described four signs of acute inflammation; tumor or swelling, rubor or redness, calor or increased local temperature and dolor or local pain. Calen, a Greek physician later recommend looking for functio laesa or a loss of function. Doctors also look for pus but a wound exudates or serum does not necessarily mean the wound is infected.