SAN DIEGO – Adoption of rapid diagnostic testing in conjunction with an antimicrobial stewardship program reduced time to initiation of optimal antibiotic therapy and markedly improved clinical outcomes in patients admitted with Gram-negative bacteremia at two Houston-area community hospitals.
Indeed, in-hospital mortality in patients with Gram-negative bacteremia plummeted from 26% immediately prior to acquisition of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry, when lab testing of bloodstream organisms was done the traditional way, to just 2% post intervention, Ashley M. Lockwood, Pharm.D., reported at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
Bruce Jancin/Frontline Medical News
Dr. Ashley M. Lockwood
Moreover, average overall hospital costs dropped from $18,644 to $15,234, for a savings of $3,410 per patient attributable to MALDI-TOF plus the pharmacist-led antimicrobial stewardship program, added Dr. Lockwood, who performed the before-and-after comparison study while at Houston Methodist Hospital System and is now the infectious disease pharmacist at Bayfront Health in St. Petersburg, Fla.
Prior studies have shown big benefits for MALDI-TOF and other rapid diagnostic tests in combination with antimicrobial stewardship, but all the research was done at tertiary medical centers. It was unclear whether the results were generalizable to the thousands of community hospitals across the nation. The new study removes any doubts on that score, Dr. Lockwood said in an interview.
“The use of MALDI-TOF coupled with near real-time antimicrobial stewardship should be incorporated in the community setting to improve time to therapeutic optimization in patients with Gram-negative bacteremia,” she declared.
The study compared outcomes in 149 patients with Gram-negative bacteremia admitted to the two community hospitals prior to acquisition of a shared MALDI-TOF system and 241 admitted post acquisition. Prior to MALDI-TOF, when the traditional culture and susceptibility results came back, the information would simply be entered into the electronic medical record. Post-MALDI-TOF, when the lab results get entered into the EMR, a third-party surveillance program known as Vigilanz Real-Time Surveillance notifies a clinical pharmacist, who then goes into the EMR to make sure the patient is on appropriate antibiotic therapy. If not, a call is made to the attending physician, who can either accept or reject the pharmacist’s recommended medication change.
Both pre- and post-MALDI-TOF it took about 20 hours from the time of the blood draw to a positive culture. But the time from that point to identification of the infecting pathogen dropped from 32 hours using the traditional method to 6.5 hours with MALDI-TOF. Time to results of susceptibility testing decreased from 48 to 22 hours. Time to antibiotic optimization for patients who weren’t already on effective therapy dropped from an average of 71 hours to 30 hours – and that’s what accounts for the dramatic reduction in mortality, according to Dr. Lockwood.
“With Gram-negative bacteremia, every hour counts. The mortality increases by 7.6% each hour, so I definitely think that reduction in mortality is real,” she said.
Although Dr. Lockwood and her coinvestigators expected to see a reduction in hospital length of stay post-MALDI-TOF, the average stay turned out to be 6.4 days in both groups. That’s probably because 6 days is already at the low end of the spectrum for patients admitted to a community hospital for bacteremia, she observed.
The initial investment for MALDI-TOF technology is roughly $250,000. That’s a drop in the bucket considering the reduced overall per-patient hospital cost and marked reduction in mortality, Dr. Lockwood observed.
She reported having no financial conflicts regarding her study, which was an unfunded research project.