1. Colorado School of Public Health | 13001 E. 17th Place, B119 | Aurora, CO 80045 | 303.724.4585 | http://publichealth.ucdenver.edu
Reducing Time to Bacterial Identification in Blood Stream Infections
Veronica Ann Broslawik, MLS(ASCP)CM | MPH Candidate – Epidemiology
University of Colorado Hospital | Clinical Laboratory – Microbiology
Discussion
MALDI-TOF MS significantly improves
laboratory processes for the identification
of bacteria causing BSIs. This highly
sensitive and specific test can help
physicians make informed decisions
about antibiotic therapy. While time to
identification is important, steps must also
be taken to decrease time to antibiotic
sensitivity results. Time to appropriate
therapy is one of the most modifiable risk
factors for mortality in patients with gram-
negative bacteremia. Every hour of delay
in appropriate therapy decreases survival
rates by 7.6%.
Public Health Impact
Implementation of MALDI-TOF MS
technology significantly decreased the
time to identification of gram negative
bacteria in the blood stream. Decreased
time to identification can improve patient
outcomes and ultimately play a role in
decreasing antibiotic resistance.
Acknowledgements
•Dr. Nancy Madinger & Dr. Bruce McCollister
•Deborah Havens, MLS(ASCP)
•University of Colorado Hospital Clinical
Microbiology Laboratory Staff especially
Mehdi Bandali and Elizabeth Matthys
•CSPH Fall 2014 Capstone Colleagues
Time to Identification
n
Mean
(hours)
95% CI
(hours)
Before MALDI 153 38.04 35.56 - 40.73
After MALDI 104 26.68 24.61 - 28.76
Background
Delay in identification and treatment of
bacteria in blood stream infections (BSIs)
can negatively impact patient outcomes.
Historically, identification of bacteria in
these infections is slow (18-72 hours).
Matrix Assisted Laser Desorption
Ionization, Time of Flight Mass
Spectrometry (MALDI-TOF MS) can
decrease time to identification of bacteria
in blood stream infections.
Objective
This study examined the time to
identification of gram negative bacteria in
blood stream infections before and after
implementation of MALDI-TOF MS
technology in a clinical microbiology
laboratory.
Methods
•Retrospective, quasi-experimental
before/after study
•Inclusion Criteria:
− Positive blood cultures
− June 2013 to August 2014
− Inpatients
− Gram negative rods
o examples: E. coli or Salmonella
− 1st positive culture
− Not a mixed infection
− Antibiotic sensitivity testing
MALDI-TOF MS identification
takes 7-15 hours less time
compared to phenotypic
identification (p-value <0.001).
Results
0
24
48
72
96
120
HourstoIdentification
Identifications Before and After Implementation of MALDI-TOF MS
Before MALDI After MALDI Mean Time to Identification Before MALDI = 38.04 hours Mean Time to Identification After MALDI = 26.68 hours
BloodCulture
Drawn
BeforeMALDIAfterMALDI
0 12 24 36 48 60 72
Hours After Culture Positivity
Culture
Positive
Timeto
Bacterial
Identification
Timeto
Antibiotic
Susceptibility
Results
38.04
26.68