272. Impact of Matrix-Assisted Laser Desorption Ionization Time-of-flight Mass Spectrometry (MALDI-TOF MS) on Time to Optimal Antimicrobial Therapy in Pediatric Patients with Positive Blood Cultures at Children’s Cancer Hospital-Egypt (CCHE-57357)

Abstract

BackgroundThe clinical microbiology laboratory at CCHE-57357 implemented the MALDI-TOF MS for pathogen identification directly from positive blood cultures in 2016. Prior to that conventional method was used. The purpose of this study was to evaluate the impact of using the MALDI-TOF MS on the time to pathogen identification, time to administration of the optimal antimicrobial treatment and on the clinical outcomes for pediatric patients at CCHE-57357.MethodsThis was a retrospective, descriptive, observational study design. Data were collected for children admitted to CCHE-57357 with positive blood cultures identified by traditional culture method from July 1, 2015 to September 30, 2015 and by MALDI-TOF MS from July 1, 2016 to September 30, 2016. Outcome measures included time from reporting of a positive blood culture until organism identification and susceptibilities, time to optimal antimicrobial treatment, and clinical outcome across the two study periods (before and after the use of MALDI-TOF MS).ResultsA total of 172 positive blood cultures were included in the analysis: 64 before and 108 after the implementation of MALDI-TOF MS. The mean time to blood cultures positivity detected by BACTEC system was similar in both time periods, while the mean time to organism identification decreased significantly by 35% from 60 to 39 hours (P = 0.001) after the use of MALDI-TOF MS. Concurrently, the time to susceptibilities was significantly reduced by 30% from 82 to 57 hours (P = 0.001) and the time to starting optimal antimicrobial therapy was reduced significantly by 33% from 81 to 54 hours (P = 0.001). Optimal antimicrobial therapy was initiated within 72 hours from the time of blood culture inoculation in 37% of pediatric patients before and 76% after the use of MALDI-TOF MS (P = 0.01). Thirty-day all-cause mortality was lower after the use of MALDI-TOF, but the difference was not statistically significant (9.2% vs. 16.9%, P = 0.122).ConclusionThe study concluded that applying MALDI-TOF technology significantly reduced the time needed to pathogen identification and to initiate optimal antimicrobial therapy. This will eventually improve patient clinical outcomes, and reduce mortality in our immunocompromised pediatric population. Disclosures All authors: No reported disclosures.