Introduction

Extract

Staphylococcus aureus is a non-motile, gram-positive cocci that colonizes in clusters. It is found world wide and is a leading cause of disease. It can normally only transiently colonize the outside and entry portals of the human body (skin, ears, eye, nasal passages, etc.), but it is estimated that 20% of humans are carriers (asymptomatic permanent colonization)¹. However, even transient colonization can lead to infection if the conditions are right; such as a breach in the protective layer of epithelial cells, or a compromised immune system. The ability to cause disease is via two mechanisms: 1) toxin production, and/or 2) proliferation of the organism, which causes tissue destruction.

Most infections remain localized at entry portals and are usually self-limiting and non-life threatening. Much less frequently, more serious infections may occur when the organism is able to invade deeper into the body (osteomyelitis, septicemia, pneumonia, etc.) (Fig. 1). These deeper infections may be extremely serious and even fatal. Because infections of S. aureus occur at a higher rate than that of many bacteria, the costs that are incurred for hospitalization and treatment can be tremendous. In just one year, 1995, in New York City, it was estimated that there were at least 13,550 cases of S. aureus infections resulting in an estimated cost of about $435.5 million².

In a study that was published in 2007 with data from the year 2003, it was found that nearly 390,000 people in the U.S. were hospitalized with S. aureus infections, with the average hospital…