Pathogenic bacteria are bacteria that can cause disease. Pathogens inflict damage on their hosts by secreting toxins. These toxins act on cell membranes or translocate across the cell membrane and disrupt normal cellular functions. However, what distinguishes a pathogen from a non-pathogen is not clear-cut. Although some organisms clearly are potentially harmful, our bodies are host to many microbes, most of which do not cause disease and many of which are beneficial. Sometimes, however, an organism in the wrong ecological niche can cause harm.
Pathogenic bacteria that tend to hit news headlines are Escherichia coli, Salmonella species, and Staphylococcus aureus (as the Methicillin-resistant form). There are other, bigger killers. For example, with the disease tuberculosis where Mycobacterium tuberculosis bacteria, which kills about 2 million people a year, mostly in sub-Saharan Africa. Other pathogenic bacteria cause infections such as tetanus, typhoid fever, diphtheria, syphilis, and leprosy.
One overlooked organism, according to microbiologists working at the University of Bath, U.K., is an organism closely related to S. aureus called Staphylococcus epidermidis. The researchers have been tracking incidents of this bacterium in relation to surgery and post-surgical infections.
S. epidermidis is normally harmless. However, the researchers have identified 61 genes that enable this normally innocuous skin bacterium to cause life-threatening illness. This information was gathered from taking samples from people who had suffered infections following hip or knee joint replacement and fracture fixation operations.
The analysis has led the lead researcher Professor Sam Sheppard to state: “Staphlococcus epidermidis is a deadly pathogen in plain sight. “Post-surgical infections can be incredibly serious and can be fatal. Infection accounts for almost a third of deaths in the UK so I believe we should be doing more to reduce the risk if we possibly can.” He has called for additional hygiene precautions to be taken in hospitals.
The research paper has been published in the journal Nature Communications and it is titled “Disease-associated genotypes of the commensal skin bacterium Staphylococcus epidermidis.”
