Newly Developed Rapid Diagnostics Can Help Stop the Spread of Disease

By Ron Sills, Nerac Analyst

With the FDA’s recent approval of the BD Diagnostics’ GeneOhm StaphSR, a rapid blood test for detecting methicillin-resistant Staphylococcus aureus (MRSA), we now have a device that can simultaneously detect both S. aureus and its MRSA form in patient blood cultures. BD Diagnostics, a division of Becton Dickinson that has focused its efforts on detecting MRSA and other pathogens responsible for healthcare acquired infections, says that this assay can accurately detect the superbug in two hours. Early detection is critical, because MRSA bloodstream infections are aggressive and can be fatal.

BD Diagnostics elevated its efforts to increase market share in pathogen diagnosis after it acquired GeneOhm Sciences in 2006. In addition, BD also gained the rights to negotiate for a business relationship to develop Accelr8’s BACcel rapid diagnostic platform, giving it exclusive rights through March 31, 2008. Meanwhile, the companies will explore a possible joint product development relationship.

Several other companies have developed and marketed assays and test kits to detect MRSA and other pathogens. Cepheid led the way with its GeneXpert Systems and Xpert Molecular Diagnostic Tests, including Xpert MRSA. These molecular diagnostic assays are based on polymerase chain reactions that also identify specific pathogens within two hours. However, instead of looking at blood cultures, samples are taken from nasal passages or skin sites, including wounds.

These devices are equally as fast and accurate as BD’s GeneOhmStaphSR, but MRSA colonization does not always imply a positive blood culture or an established infection. The BD assay is more discriminating, because it tests directly for the presence of staph and MRSA in blood cultures.

Biomerieux, Invitrogen and 3M also recently entered the market for rapid diagnosis of MRSA and other pathogens.

Leading Cause of Health Problems

Antibiotic-resistant pathogens have emerged as one of the leading health problems in the United States and abroad. Over 70 percent of pathogenic bacteria exhibit resistance to various antibiotics. Significant pathogens such as Mycobacterium tuberculosis, Escherichia coli, Streptococcus pneumoniae, Treponema pallidum (syphilis), Neisseria gonorrhea, and Chlamydia trachomatis each have mutated into strains resistant to traditional antibiotics. Resistant virus strains are also well established, including HIV and hepatitis. The influenza virus is perhaps the most dynamic, altering its surface proteins every few years, often resulting in new strains that cannot be controlled through treatments or vaccines.

More recently, MRSA, or methicillin-resistant Staphylococcus aureus (S. aureus), has become the best-known resistant bacteria. Outbreaks have been reported across the country in recent years, affecting hospital patients, students, and athletes. S. aureus is a common skin organism that occurs naturally in up to 30 percent of the population without causing infection or disease. However, when it invades the body through open cuts or wounds, suppressed immunity, or overall poor health, it can cause localized infections such as pimples or abscesses. More aggressive infections include toxic shock syndrome.

Methicillin, a semi-synthetic penicillin formulation, was extremely effective in treating staph infections until mutant strains of S. aureus resistant to this antibiotic evolved. Vancomycin is often given as a second line therapy against MRSA. However resistance to this antibiotic has been reported as well. Drug resistance among this species has become so prevalent that the term MRSA can now refer to multidrug resistant S. aureus.

How the Disease Spreads

MRSA infections are predominantly seen in hospitals or other healthcare settings such as nursing homes or outpatient clinics, which are often plagued by nosocomial, or secondary infections acquired through poor infection control practices. Other populations in close proximity in classrooms, dormitories, and locker rooms are also at risk. Skin organisms such as MRSA can be transmitted easily from person to person. Sharing personal items such as towels, razors, or toothbrushes can also promote swift transmission. Athletic contact during football, basketball or soccer has been implicated in several outbreaks of MRSA.

The Centers for Disease Control and Prevention estimates that close to 2 million nosocomial infections annually result in nearly 20,000 deaths and associated costs close to $50 billion. Concurrently, nearly 100,000 people are hospitalized for MRSA infections annually, accounting for approximately 5,000 deaths and associated costs up to $2.5 billion. While the number of people affected by nosocomial and MRSA infections pales in comparison with the global pandemics of tuberculosis, AIDS or malaria, the continued emergence of these infections is a valid concern.

IP Investment Indicates Increased Interest

BD, Cepheid, Biomerieux, Invitrogen, 3M and other companies are investing in intellectual property to protect their technologies and business interests. A total of 77 patents and patent applications for rapid detection systems for MRSA and other antibiotic resistant organisms have been filed in the past five years, but the number of those which are eventually commercialized is hard to know. Rapid diagnostics are expected to gain additional momentum due to heightened attention on bioterrorism, food safety, and hospital-acquired infections.