APHL 2019 POSTER ABSTRACTS
Evaluation of the Vitek MS v3.0 System in the Identification
of Clinically Relevant Molds
S. Realegeno, P.M.K. Larkin, A.J. Dayo, D. Contreras, R. Mirasol, L.
Mortimer, K. Gih and O. Garner, University of California, Los Angeles
Molds are important opportunistic pathogens that can cause
severe disease, particularly in immunocompromised populations.
The rapid identification of molds in clinical specimens is critical
for appropriate diagnosis and treatment. Currently, routine
identification of molds in clinical specimens is primarily based
on macromorphology and microscopic examination of cultured
specimens. Some challenges associated with conventional
identification methods include culturing lengths for isolation (up to 6
weeks), the induction of distinctive morphological features in culture
conditions (i.e., sporulation), and the availability of skilled laboratory
personnel trained in mycology. Matrix-assisted laser desorption
ionization-time of flight mass spectrometry (MALDI-TOF MS) is a
tool increasingly being used in clinical laboratories for the rapid
identification of bacteria and fungi. In order to implement MALDI-
TOF MS in our laboratory for the routine identification of molds,
we evaluated the FDA-cleared Vitek MS v3.0 system on cultured
specimens from clinical isolates. Specimens were processed
using the Vitek MS Mold Kit. We first verified microbial inactivation
using the kit’s reagents, which yielded supernatant containing
the extracted protein. Supernatant from 37 isolates spanning
various mycoses were cultured on Inhibitory Mold Agar (IMA) and
examined for growth for a total of 8 weeks. No growth was noted
on all 37 isolates, demonstrating that the components of the Vitek
MS Mold Kit adequately inactivated specimens. Clinical isolates for
identification were subcultured on primary isolation media, which
included IMA and Sabouraud Agar with Brain Heat Infusion (SABHI).
In addition, Potato Flake Agar (PFA), which is used for sporulation,
was also validated on select species. Specimens were collected
from culture media at various time points to determine the earliest
and optimal time point for detection. Mold identifications were
obtained from specimens cultured on SABHI, IMA, and PFA as early
as the first day of visible growth. However, variability in identification
was noted based on target slide spotting for a single extract as well
as the extraction time point. In some instances, no identification
was obtained initially, but repeat extraction of the same culture
on a different day yielded accurate results. MALDI-TOF MS can
improve the current workflow for mold identification by reducing
reporting times through the identification of cultured specimens
at earlier growth stages. A more rapid identification method can
potentially lead to improvement in patient diagnosis and therapeutic
management.
Presenter: Susan Realegeno, CPEP Fellow, University of California,
Los Angeles, [email protected]
Skin Colonization Screening for Carbapenem-Resistant
Acinetobacter baumannii using the EnviroMax Plus ®
Environmental Sampling Swabs
L. Smith 1 , B. Rane 1 , M. Jahan 1 , H. Schuckel 1 , A. Smith 2 , M.
Vowles 2 , L. Rider 2 , A. Rossi 1 ; 1 Utah Public Health Laboratory, 2 Utah
Department of Health
Carbapenem-resistant Acinetobacter baumannii (CRAB) is an
important nosocomial pathogen causing high mortality and
morbidity in debilitated patients worldwide. Identification of CRAB-
colonized patients and environmental sources of infections in
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healthcare facilities is essential for the implementation of infection
control measures. It is widely accepted that Acinetobacter is an
efficient skin colonizer and that this site is optimal for organism
recovery. It has also been shown that collection with moistened
sponges is superior to swabbing with conventional rayon swabs.
Based on this information we assessed whether the EnviroMax
Plus ® (EMP) swabs (Puritan ® ), a foam sponge collecting device
designed for environmental sampling, could be effectively used
for skin colonization studies. Here we evaluated the performance
of EMP swabs for the recovery of Acinetobacter from the skin of
healthy individuals by comparing them to a conventional Amies
medium-based nylon swab system (eSwab™, Copan). We also
report on the successful implementation of EMP swabs in a point
prevalence survey aimed at addressing CRAB colonization in a long-
term care facility (LTCF) with a ventilator unit in Utah.
For the performance evaluation, 29 healthy volunteers at the Utah
Public health Laboratory were swabbed on each forearm, hand
and half of the forehead with either an EMP or an eSwab™ swab.
The swabs were submerged in 10 mL of tryptic soy broth (TSB) and
incubated overnight at 36°C. 100 µL of the enrichment broth was
plated on Leeds Acinetobacter Medium (LAM) and growth scored
the following day. Up to four colonies growing on LAM were used for
bacterial species identification by MALDI-TOF mass spectrometry
with a Brucker Biotyper instrument. During the CRAB-colonization
investigation at the LTCF, one EMP swab was used to sample the
axilla and groin of patients. TSB broth enrichment was conducted
as described above, but in this case a β-lactam-supplemented
chromogenic medium (CHROMAgar™ Acinetobacter with MDR
supplement) was used for selection of CRAB. Species identification
from presumptive CRAB+ colonies was performed through MALDI-
TOF analysis.
Colonization with Acinetobacter spp. (A. ursingii, A. pittii, A.
baumannii and A. schindleri) could be detected in three volunteers
(10.3%) using the EMP swabs. Collection with the eSwab™ swabs
identified only one additional individual colonized with A. pittii
(3.4%). Use of EMP swabs resulted also in greater non-target flora
recovery when compared to eSwab™ swabs (27.5% vs 13.8%). In
the LTCF investigation, 47 patients were sampled using EMP swabs
and CRAB was recovered from the skin of 10 of them (21.3%).
These data reproduce previous observations indicating a better
performance of sponge-collecting devices in CRAB-colonization
screening when compared to conventional swabs and demonstrate
the suitability of EMP swabs for sampling intact skin.
Presenter: Alessandro Rossi, Utah Public Health Laboratory,
Taylorsville, UT, [email protected]
Dissemination of OXA-23 Producing Acinetobacter
baumannii during an Outbreak in a Long-term Care Facility
E. Young, K. Oakeson, A. Rossi and R. Atkinson Dunn, Utah Public
Health Laboratory
Background: Acinetobacter baumannii is a highly adaptive organism
associated with hospital and long-term care facility infections.
A. baumannii readily achieves antibiotic resistance, either through
intrinsic or acquired resistance through transformation.
A. baumannii can colonize almost any surface and survive
commonly used disinfectants, making environment eradication
difficult. Immunocompromised and other vulnerable patients, such
as those in long-term care facilities or nursing homes, are a target
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