A new method to determine if bacteria are susceptible to antibiotics within a few hours could slow the appearance of drug resistance and allow doctors to more rapidly identify the appropriate treatment for patients with life threatening bacterial infections.
According to the Centers for Disease Control and Prevention, antibiotic resistance causes two million illnesses and 23,000 deaths annually, costing the U.S. economy approximately $20-billion a year in direct health care costs and nearly eight million extra days in the hospital. Indeed, bacteria are evolving resistance to antibiotics much more quickly than global biomedical research efforts are delivering new drugs to market, leading to the appearance of infections caused by bacteria that are now resistant to every therapy.
Rapid antimicrobial susceptibility testing allows doctors to discriminate between infections caused by drug sensitive bacteria, which can be treated with safe and effective antibiotics developed in what scientists call the golden age of drug discovery (the mid-20th century) such as penicillin, and those caused by drug resistant bacteria, which might require newer antibiotics, such as daptomycin or cubicin. This approach will decrease the emergence of resistance by reserving the newest drugs for those infections where they are most needed.
In a paper published online this week in the journal EBioMedicine, the scientists from UC San Diego reported the development of a rapid susceptibility test for Staphylococcus aureus, a bacterium that causes some 60 percent of hospital-acquired infections and which has spread in communities, causing pneumonia and a variety of skin and tissue infections in both healthy and immune-compromised individuals.
It's important to rapidly discriminate between drug resistant strains (commonly termed MRSA for methicillin-resistant S. aureus) and drug sensitive strains, since these infections can progress rapidly, especially MRSA strains with additional resistance to newer antibiotics designed to treat pathogens that are now appearing in hospitals.