Lab Matters Summer 2019 - Page 69

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, 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 PublicHealthLabs @APHL 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, 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 Summer 2019 LAB MATTERS 67