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MALDI-TOF identification demonstrated direct clinical result
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WASHINGTON, D.C. — Researchers have found that using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, or MALDI-TOF, to identify organisms on day 1 can have a direct clinical result, according to a poster presentation here at ICAAC 2014.
“Faster identification using MALDI-TOF assists the clinician in assessing the significance of a blood culture isolate on day 1,” Kathryn French, PhD, of Public Health England Laboratory in Birmingham, United Kingdom, and colleagues wrote. “It can allow earlier appropriate choice of antimicrobial agent even in the absence of susceptibility testing and help narrow down the potential source, providing a focus for investigation in a more timely way than conventional techniques alone.”
French and colleagues evaluated 115 cases of positive blood cultures during a 4-week time that had organisms seen on Gram’s stain. They compared the clinical advice given on day 1, before the organism identification, with the clinical advice given on day 2, after the organisms were identified. They then compared culture results with results of direct MALDI-TOF identification on day 1.
Among the 115 cases, 73 had MALDI-TOF identification. Among those, 70 (95.5%) had results that were concordant with the results on culture. The researchers found that in 28 of the 115 cases, the early MALDI-TOF identification would have resulted in a clinical benefit. In 11 of the cases, a different source of infection would have been identified, and 11 would have had a different antibiotic indication. For five of those patients, they would have received appropriate antibiotics 24 hours earlier. For 14 cases, additional clinical input would not have been required.
“By facilitating the use or more narrow-spectrum antibiotics, the direct MALDI-TOF method can be viewed as contributing positively to antimicrobial stewardship,” the researchers wrote. “When considering the cases where broader spectrum antibiotics are indicated, the organism identification allowed more prompt appropriate antimicrobial therapy, which may otherwise have been delayed.”
For more information:
French K. Abstract D-903. Presented at: Interscience Conference on Antimicrobial Agents and Chemotherapy; Sept. 5-9, 2014; Washington, D.C.
Disclosure: The researchers report no relevant financial disclosures.