About MRSA, MSSA and Related Infections

Why MRSA screening?
Drug-resistant MRSA (methicillin-resistant S. aureus) and MSSA (methicillin-sensitive or susceptible S. aureus) infections are a growing problem in healthcare facilities around the world. Typically harmless, S. aureus pathogens can enter the body and cause serious illness, especially in older adults and people who are ill or have weakened immune systems.

The highly contagious bacteria that cause MRSA infections are resistant to all but the most powerful broad-spectrum antibiotics. The Centers for Disease Control estimates that in 2005, there were approximately 90,000 persons in the U.S. diagnosed with severe MRSA infection, and an estimated 19,000 patients died. The incidence of MRSA infections has been rising and some experts estimate that over 60% of hospital-acquired S. aureus infections are now antibiotic-resistant.

MSSA refers to S. aureus infections that are often serious but that can be treated with a wider range of standard antibiotics than MRSA infections. A screening test that distinguishes MRSA and MSSA infections is particularly important for physicians making treatment decisions in the hospital setting, where these infections are most likely to be serious and potentially lethal.

Individuals colonized with MRSA or MSSA can pass the germ to others, even if not actually infected themselves. MRSA and MSSA infections are spread through direct contact with carriers or with surfaces contaminated with the bacteria. They cause infection when they enter the body through an opening caused by a wound or by a medical intervention.

Patients in hospitals are at an increased risk for MRSA and MSSA infections. The S. aureus pathogen can be spread by medical personnel, medical instruments, or from exposure to bacteria on furniture or other surfaces. Routine invasive medical procedures performed in hospitals create openings for MRSA and MSSA to enter the bloodstream. In addition, many patients have weakened immune systems that put them at increased risk. Once a MRSA or MSSA bloodstream infection is established, it can result in serious illness and death, while lengthening hospital stays and increasing medical costs.

A study from Duke University researchers estimates that compared to patients who do not develop surgical site infections, a surgical patient infected with MRSA increases hospital costs by more than $61,000, and a patient with a MSSA surgical site infection increases hospital costs by over $24,000. These researchers also found a seven-fold increased risk of death within 90 days for patients who developed MRSA-related surgical site infections as compared to those who did not. Another study published in the American Journal of Infection Control showed hospitals could save up to $500 per patient by screening all ICU admissions for MRSA.

In a separate recent study, researchers call for increased preventative interventions to limit invasive S. aureus infections, which were found to occur at high rates in patients undergoing certain surgeries, such as cardiothoracic procedures.

Successful MRSA and MSSA control efforts rely on screening potential carriers to prevent the spread of the disease. Rapid diagnostic screening to identify MRSA and MSSA carriers at the time of patient admission aids in effective control by enabling special precautions to be used with infected patients, their facilities and the personnel who care for them. MRSA typically has been identified using bacterial culture techniques that require at least two days for results, during which time the bacteria can spread through the facility. A number of molecular diagnostic MRSA assays that provide test results more quickly have become available in recent years, but they require special handling and storage, can be complex and costly to run, and may have only moderate accuracy. The Detect-Ready® MRSA Panel provides an accurate, easy-to-use comprehensive solution for screening S. aureus carriers.

The Detect-Ready MRSA Panel also uniquely meets draft FDA guidelines for molecular MRSA testing that were released in January 2011. The guidelines state that to gain FDA approval, MRSA screening tests should be able to routinely distinguish between MRSA and Staphylococcus aureus (SA) variant strains, such as MSSA. The Detect-Ready MRSA Panel is the only screening test on the market or in late-stage development with the proven ability to routinely distinguish between these pathogens.
Copyright 2012 Detect-Ready® and Molecular Detection Inc.