Diagnostics Are Helping Counter Antimicrobial Resistance, But More Work Is Needed

Antimicrobial resistance (AMR) threats to patient health are becoming more widely recognized and diagnostics manufacturers are making significant progress in combatting the overuse of antibiotics. There is still a lot of work to be done, however. A recent health scare for Rick Bright, Ph.D., director of the Biomedical Advanced Research and Development Authority (BARDA), HHS, the very agency working to combat emerging infectious diseases (EID) and other threats, highlights the lingering risks. 

During the 10th Public Meeting of the Presidential Advisory Council on Combating Antibiotic-Resistant Bacteria (PACCARB) in September, Bright recounted his own experience with a multidrug-resistant organism (MDRO). Having contracted the MDRO from a scratch while gardening, he ended up seeking treatment from a number of urgent care clinics before finding one that would treat and culture the wound. According to minutes from the council meeting, Bright described facing potential surgery and even amputation of his thumb. “Costly” rounds of two new antibiotics eventually proved effective, but Bright had to work to track down his culture results, which were positive for methicillin-resistant Staphylococcus aureus (MRSA), he shared. 

“The experience demonstrates the need for new standard procedures, such as immediate culturing and point-of-care diagnostics in the emergency department, so providers can prescribe the right treatment. In Dr. Bright’s case, this approach would have resulted in immediate, effective treatment; dramatically lower costs; much less risk of exposing others in the hospital to infection; and preservation of hospital resources,” according to the PACCARB meeting minutes.

Sherrie Smartt, medical director, clinical studies manager, and regulatory affairs manager at Thermo Fisher Scientific, tells MD+DI that national initiatives such as the PACCARB “have recently brought increasing focus to the area of appropriate antibiotic use and the call for better tools for clinicians to make informed decisions on antibiotic prescription.”  

One of those tools is “precision medicine,” a term the National Research Council, which leads the Precision Medicine Initiative with the National Institutes of Health (NIH) and other research centers, prefers over the older term, “personalized medicine,” Smartt said. “They define this term as a discipline that ‘aims to understand how a person's genetics, environment, and lifestyle can help determine the best approach to prevent or treat disease.’ Precision medicine utilizes population health research and big data to ‘predict more accurately which treatment and prevention strategies for a particular disease will work in which groups of people.’ ”  

Smartt (at left) said that precision medicine allows “healthcare providers to customize therapies based on each individual patient’s diagnosis, clinical condition, and response to therapy via unique biomarker measurements—including laboratory and other diagnostic tests. The term has primarily been used when referring to cancer treatments, but today many healthcare providers are also using a ‘personalized’ or precision medicine approach to tailor the best drugs to  help fight an infection and to determine how long those drugs should be given to each patient for the best effect.”

Diagnostics are playing a central role in precision medicine. “New diagnostic devices for micro-organism identification, antibiotic sensitivity, and patient response to therapy can aid in clinical decision-making and enhance the practice of personalized or precision medicine,” Smartt said. “Especially in light of growing antibiotic resistance, doctors need more tools to help quickly determine if their patient is presenting with a bacterial infection, if an antibiotic is truly needed and how long it should be given.”

One relatively new assay could prove particularly useful. “In 2017, the BRAHMS procalcitonin or PCT assay was FDA cleared for use in antibiotic stewardship, as an aid to improve the use of antimicrobial medications,” she said. “A sensitive PCT assay can be used to help determine when to start and stop antibiotics in lower respiratory tract infections and when to stop antibiotics in suspected or confirmed sepsis, thereby personalizing appropriate antibiotic treatment. Using PCT—to help know when to treat patients using antibiotics and when enough [of] the correct antibiotics have been used to adequately control the infection—may help to reduce adverse events associated with the overuse of antibiotics. In addition, an increasing PCT can help identify the risk of a patient progressing to severe sepsis or septic shock—a more severe form of infection resulting in organ system dysfunction with a high risk of death. This alerts the physician to reevaluate the patient and treatment and make sure they are transferred to the best location for appropriate level of care.

“Since the typical PCT test can be done in under an hour, trending PCT levels will support physicians in knowing if their treatment choice is the correct one,” she continued. “The PCT trend is the patient’s and physician’s friend, as the PCT values will be routinely low in viral infections and elevates in bacterial infections.   In bacterial infections, the PCT will decrease over time with the correct antibiotic therapy. In cases where PCT values are still on the rise after 12-24 hours of antibiotics, the physician will need to re-evaluate the treatment options and consider changing antibiotics as the bacteria causing the infection may be resistant to the first treatment given to the patient. All of these decisions can assist the physician to ensure precise personalized medicine is being delivered quickly, before a molecular test or bacterial cultures results are available.”

Additional medical devices to combat infectious diseases are needed, too. “Other examples of innovation in medical devices combatting infectious disease include ultraviolet blood irradiation (UVBI) for the treatment of hepatitis C, improvements in polymerase chain reaction that are helping to detect infectious disease and pathogens more quickly, and new hemopurifying devices.”

Smartt said that Thermo Fisher Scientific remains committed to joining the global health challenge effort to fight AMR and is an official signatory of the AMR Industry Alliance. “The company recognizes the importance of all five areas of commitment for the AMR Challenge; however, a specific area of focus includes the commitment to improve appropriate antibiotic use, thereby ensuring access to these drugs,” she said. “PCT provides physicians a valuable diagnostic aid in antibiotic decision making for lower respiratory tract infections (LRTI) and sepsis supporting appropriate use of antimicrobials. PCT acts as a sensitive and specific biomarker for the body’s inflammatory response to bacterial infection. The biomarker helps stratify the severity of infection as well as the effectiveness of source control; thus, supporting physicians in decisions to safely and appropriately initiate (LRTI) and discontinue antimicrobial treatment (LRTI, Sepsis).”     


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