Dr Ken Thomson has been involved in the field of antibiotic research for over 25 years. As a clinical professor at the University of Louisville’s Department of Pathology and Laboratory Medicine, he has seen antimicrobial resistance in carbapenamase-producing organisms (CPOs) – so named for their ability to produce an enzyme that counteracts the effects of powerful carbapenem antibiotics – turn from a rare evolutionary quirk into an ever-present threat to the effective treatment of an infection. "We’re running out of antibiotics," says Thomson. "And we’re running out of time."

The result has been a high-mortality global pandemic of infections by CPOs, and without the development of new antibiotics, microbiology labs have been left to hold the line. "If labs cannot detect CPOs, patients are going to receive inappropriate therapy," explains Thomson, resulting in an enormous, uncontrollable resistance problem. "Labs therefore require rapid, accurate systems capable of identifying CPOs."

"The BD Phoenix system is based on a unique detection technology that provides accurate, automated susceptibility and bacterial infection results," explains Bill Folkerts, head of ID/AST global marketing at BD Life Sciences – Diagnostic Systems. "The BD Phoenix CPO detect test has been incorporated into the routine panels that are used for testing. It is the only automated phenotypic-based, rapid approach towards carbapenamase detection in the market."

Reduced uncertainty

The incorporation of the BD Phoenix CPO detect test into a routine panel is in response to the seriousness of the problem confronting microbiologists – it’s also unique in the marketplace when it comes to detection technology. "It’s a clear differentiator," says Folkerts. "Currently, the approach with other systems is that you get a susceptibility result. There may be an indication that there could be a CPO-resistant organism, but then offline testing is needed in order to clearly identify that. The BD Phoenix CPO detect test, meanwhile, allows that process to occur in a routine fashion."

The fact that the presence of a CPO is determined by the BD Phoenix on an automated system, and not individual microbiologists, also serves to diminish uncertainty and increase sample throughput. "Manual tests rely on someone at the bench to interpret them and when a borderline result occurs, it is difficult, sometimes impossible, for microbiologists to interpret them accurately," Thomson explains. "The BD Phoenix CPO detect test does a carbapenamase test on a Gram-negative isolate that has an antibiotic susceptibility test. The machine reads the test, so you don’t have any problems with laboratory staff not knowing whether a borderline test is really positive or negative."

In addition, the BD Phoenix instrument is capable of automatically classifying the type of CPO present in the sample. "That, again, is unique," says Folkerts. "The ability to not only determine the presence of a CPO, but also to identify its Ambler classification, drastically impacts the appropriate therapeutic choice for the patient."

New agents have now been developed that are effective against CPOs that produce Class A carbapenamase. "These new agents should only be used on infections with Class A carbapenamases," affirms Thomson. "If there’s a Class B carbapenamase, these organisms are intrinsically resistant. The BD Phoenix system can let you know when to use these new agents."

Above all, the BD Phoenix is practical. "You just inoculate a panel to put into the machine, and walk away," says Thomson. "It will incubate for six to eleven hours and then it’ll give you a result. So, there’s not much hands-on time, especially compared with other state-of-the-art rapid tests that require manual use."