Potential Wound Pathogens

Majority of all microorganisms are less than 0.1mm in diameter. No wonder they are called microorganisms and can only be seen with a microscope.

Microorganisms can be classified into groups such as bacteria, fungi, protozoa and viruses. This categorization is on the basis of structure and metabolic capabilities of these microorganisms. Let’s look at these microorganisms in more detail.


Bacteria are relatively simple cells and can be further categorized on the basis of their shape and cell wall. There are Cocci that have a spherical shaped cell, bacilli that are rod shaped and sprirochaetes that are spiral. These three can be categorized together. Cocci and bacilli however, are also found in pairs, chains and irregular clusters.

These bacteria can be seen using a bacteriological staining process called Gram staining. After this process Gram-positive bacteria appear purple and Gram-negative bacteria appear red, thus helping in the identification.

There are also certain species of bacteria that are not stained with the Gram reaction. These bacteria e.g. Clostridia, need specialized stains.


Fungi are larger and more complex cells as compared to bacteria. Fungi can either be single celled yeast or a multi-cellular organism that have nuclei within a cell membrane. Fungi are usually produce superficial infections that are found on the skin, nails and hair.


Protozoa is another single celled organism that has a fragile membrane but does not have A cell wall. The most significant association of protozoa is found with infected skin ulcers.


Viruses are composed of nucleic acid which is a genetic material. This is enclosed in a protein coat or a membranous envelope. We do not see viruses generally causing  wound  infections however, bacteria might infect skin lesions which are formed during the course of a viral disease.

One should clearly note that different microorganisms are able to exist in polymicrobial communities. This is usually the case within the margins of a  wound .


First found in the United Kingdom in the 1980s, Methicillin resistant Staphylococcus aureus or MRSA is still a cause of concern for healthcare practitioners.

Today many different strains of Methicillin resistant Staphylococcus aureus can be found. These affect a large number of individuals in various healthcare settings. The degree of infections can range in severity from simple  wound  colonization that does not need aggressive treatment to a systemic infection such as bronchopneumonia that can prove to be fatal. Evidence suggests that this microbe is no more pathogenic in a  wound  than the non-resistant version.