Hospital acquired infections (HAIs), also called nosocomial infections to better describe the range of places they can occur, have become a major health concern. In the U.S., between 5% and 10% of patients admitted to acute care hospitals acquire infections. This accounts for over two million patients per year, and these infections result in over 90,000 deaths per year. Over one-quarter of HAIs occur in ICUs, but nursing homes and rehabilitation centers are also impacted.
The cost of HAIs is significant and troubling; in 2005, it was estimated at $4.7 billion per year in the U.S. alone. Given the increased incidence in certain medical conditions and the growth in hospital populations and cost of stays, as well as the expense of treating some advanced cases, Kalorama estimates that nearly $6 billion per year is spent on treatment and extended hospital stays.
Yet, despite the cost and negative impact on patients, pharmaceutical companies have not responded as we would expect. This, in our view, leaves open an opportunity for new treatments from innovative biopharmaceutical companies.
The type of infections vary, with the most common being pneumonias and urinary tract infections, accounting for 60% of hospital acquired infections, but conditions like MRSA continue to increase. It is estimated that MRSA cases have doubled over this decade. Drug-resistant pneumonia, Clostridium difficile, Acinetobacter baumannii, and MRSA are the most prevelant hospital acquired infections.
Pneumonia is a leading cause of death among the elderly and people who are chronically and terminally ill, and are therefore, normally hospitalized in acute care, short-stay, or extended-care hospitals. Nosocomial pneumonia is pneumonia acquired during or after hospitalization for another illness or procedure with onset at least 72 hours after admission. Up to 10% of patients admitted to a hospital for other causes subsequently develop pneumonia.
C. difficile is a bacterium that can cause symptoms ranging from diarrhea to life-threatening inflammation of the colon. From 1996 through 2003, there were an estimated 264,000 hospital discharges for which Clostridium difficile-associated disease was listed as a diagnosis.
Acinetobacter baumannii is emerging as a cause of numerous global outbreaks and is displaying ever-increasing rates of resistance. There are reports of multidrug resistant (MDR) A. baumannii from hospitals around the world. More recently, military and nonmilitary personnel returning from operations in Iraq and Afghanistan have harbored infections caused by MDR A. baumannii.
Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for difficult-to-treat infections in humans. It may also be referred to as multiple-resistant Staphylococcus aureus (as methicillin is no longer on the market). MRSA is, by definition, a strain of Staphylococcus aureus that is resistant to a large group of antibiotics called the beta-lactams, which include the penicillins and the cephalosporins.
MRSA is especially troublesome in nosocomial infections. In hospitals, patients with open wounds, invasive devices, and weakened immune systems are at greater risk for infection than the general public.
Recent reports indicate that there is a nationwide epidemic of MRSA in the United States. A 2007 CDC report on emerging infectious diseases estimated that the number of MRSA infections treated in hospitals doubled nationwide, from approximately 127,000 in 1999 to 278,000 in 2005, while at the same time deaths increased from 11,000 to more than 17,000.