Antibiotic Resistance

July 25, 2017

Definitive diagnostics fight AMR

Misdiagnosis and inappropriate use of antibiotics set the scene for antimicrobial resistance (AMR). For respiratory infections like flu and strep, numerous studies have shown that conventional rapid antigen tests have sensitivities in the range of 50 to 60 percent, making the diagnostic call about the same as a coin toss. The results often need to be sent to a lab for confirmation via PCR-based molecular tests or viral culture. This results in the loss of precious time when someone is sick and spreading the virus. In addition, misdiagnosis can lead to the inappropriate use of antibiotics.

Having definitive diagnostics at the point of care (POC) can make a world of difference. CLIA-waived real-time PCR testing can deliver highly accurate lab-quality results for flu, strep, RSV, and more in 20 minutes or less and does not require confirmatory testing. A 2016 study by Nolte that compared a PCR-based POC system to a lab reference standard found that the sensitivity and specificity for flu A and B were 100 percent for the POC system. While these numbers exceeded the claimed performance of the system label, it’s clear that the system gives the clinician definitive answers while the patient is still present. Providing greater certainty about whether antibiotics are needed and ensuring the right antibiotic is delivered can lead to more appropriate antibiotic use—which is the heart of the antibiotic stewardship philosophy.

—Dr. Alan Wright, Chief Medical Officer
Roche Diagnostics
Provider of the cobas Liat PCR System for use at POC

Liquid based microbiology

Institutions around the world are feeling pressure to avoid treatment of preventable readmissions and HAIs. Beyond the obvious need for exemplary patient care, reimbursement is often withheld when patients contract infections during a hospital stay.

One way to decrease the spread of dangerous infections is with robust screening programs which test any admitted patient for infection, such as MRSA, VRE, and C. difficile. When looking for these superbugs, accuracy and efficiency are critical, which is why many laboratories are switching to liquid-based microbiology (LBM) collection and transport systems for their surveillance programs. These multi-use collection systems use flocked swabs to collect and release more sample into the transport media, resulting in improved quality of both traditional and contemporary microbiology assays.

LBM systems standardize and simplify testing, and manufacturers of molecular surveillance tests are taking note, adding LBM products to package inserts as approved collection and transport devices.

—Amanda Schmidt
Sr. Marketing Channel Manager
COPAN Diagnostics, Inc. Manufacturer of FecalSwab and ESwab

Antimicrobial susceptibility testing

Antimicrobial susceptibility testing (AST) is helpful for informing antibiotic selection for organisms in critical illnesses such as bloodstream infections. However, conventional AST techniques typically require days to provide actionable results, delaying appropriate care for critically ill patients, and leading to increased mortality, excessive antimicrobial use, and adverse effects such as C. difficile infection.

Genetic resistance markers can be detected using PCR on automated platforms with results available in 60 to 90 minutes from positive blood cultures. These rapid results can positively impact therapy escalation/de-escalation and clinical outcomes. Additionally, resistance genes have been shown to detect the potential for resistance even in cases where antimicrobials appear active by conventional AST but may not be effective clinically. Moreover, resistance genes also provide epidemiological information that can aid in tracking and controlling outbreaks, and earlier results allow for rapid isolation of patients with resistant infections, improving infection control.

When molecular diagnostics are incorporated into a hospital’s antimicrobial stewardship program (ASP), that has been shown to reduce time to effective therapy, length of hospital stay, and mortality. Therefore, these “game changers” should be routinely utilized to improve patient care and fight antibiotic resistance.

—Tristan Timbrook, PharmD, MBA, BCPS
Post-Doctoral Outcomes Pharmacy Fellow in Antimicrobial Stewardship
Advisor to GenMark Diagnostics

Combat AMR with testing

Antimicrobial resistance (AMR) has drawn significant attention from global health organizations like WHO and the CDC, while state and federal resources in the U.S. have been mobilized to try to address the problem from all angles.

A central theme in many of these efforts is the need for faster, more accurate diagnostics. The CDC includes development of new diagnostic tests as one of its four core actions for addressing AMR.

The development of new molecular tests for the rapid detection of carbapenem-resistant enterobacteriaceae (CRE) is one example of recent progress along these lines, and an example of how clinical labs will continue to play a critical role in the fight against AMR.

—Zack Crowther
Marketing Manager, Healthcare Associated Infections