2038. Invasive Mucormycosis Management: Mucorales PCR Provides Important, Novel Diagnostic Information
Session: Poster Abstract Session: Diagnostics: Mycology
Saturday, October 6, 2018
Room: S Poster Hall
Posters
  • MM 0839 REV0 0918 IDWeek 2018 Mucor Abstract Poster FINAL APPROVED.pdf (90.6 kB)
  • Background: In immunocompromised patients, high mortality and morbidity of invasive mucormycosis (IM) remain significant healthcare issues due in part to confusion of IM with invasive aspergillosis (IA) and failure to initiate appropriate therapy. A validated Mucorales (MUC) PCR detects the causative agents of IM with good sensitivity and specificity, as reported previously (M-227, ICAAC 2013). Published studies have not definitively determined the frequency of patients for whom pulmonary IA is suspected but IM is present. We aimed to (1) estimate the frequency of MUC PCR positivity in bronchoalveolar lavage (BAL) samples submitted for Aspergillus (ASP) PCR panel testing.

    Methods: We identified 1067 clinical BAL specimens originally submitted to a reference laboratory for ASP PCR panel testing. Eluates from DNA extraction were tested by MUC PCR, which detects known pathogens from 7 Mucorales genera (Apophysomyces, Cunninghamella, Lichtheimia [previously Absidia], Mucor, Rhizomucor, Rhizopus and Saksenaea).

    Results: The proportions of MUC PCR and ASP PCR positive BAL specimens were 1.5% (16) and 6.9% (74), respectively. 87.5% (14/16) of the MUC positive (POS) were ASP negative (NEG). One patient had 2 MUC PCR POS BAL samples within the testing period. The MUC quantification averaged 20,000 copies per mL BAL (range 24 to 266,000), which is >1000-fold above the assay the 20 copies/mL limit of detection (LOD). Two of the ASP POS’s were MUC POS (~400 and 20-fold above LOD). For patients with MUC POS BALs, physicians requested on average 6.3 pneumonia-related tests (e.g. ASP PCR, Galactomannan, Legionella PCR, etc) within two weeks of the tested BAL. In total 94.0% (85/91) of these orders yielded NEG results. The MUC PCR was physician-ordered in only one (6.25%) of the MUC POS BALs.

    Conclusion: In BAL samples submitted for IA testing, 16 cases (1.5%) had POS MUC PCR. The observed 5:1 (ASP:MUC) ratio approximates published literature on invasive mould incidence. MUC POS concurrent with NEG results for other pathogens suggest potential missed opportunities for MUC early diagnosis and treatment in cases of suspected invasive mould.

    Kyle Wilgers, BS1, Joel Waddell, DO2, Aaron Tyler, BS1, Michelle Altrich, PhD1, Allyson Hays, MD3, Steve Kleiboeker, PhD1, Dwight Yin, MD, MPH4 and Mark Wissel, PhD1, (1)Viracor Eurofins Clinical Diagnostics, Lees Summit, MO, (2)Children's Mercy Hospitals & Clinics, Kansas City, MO, (3)Hematology/Oncology, Children's Mercy Hospital - Kansas City, Kansas City, MO, (4)Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO

    Disclosures:

    K. Wilgers, Viracor Eurofins Clinical Diagnostics: Employee , Salary .

    J. Waddell, Viracor-Eurofins: Collaborator , No financial benefit .

    A. Tyler, Viracor Eurofins Clinical Diagnostics: Employee , Salary .

    M. Altrich, Viracor Eurofins Clinical Diagnostics: Employee , Salary .

    A. Hays, None

    S. Kleiboeker, Viracor Eurofins Clinical Diagnostics: Employee , Salary .

    D. Yin, Viracor-Eurofins: Collaborator , No financial benefit . Marion Merrell Dow Fund: Grant Investigator , Research grant . Astellas: Investigator , Research grant . Merck: Investigator , Research grant .

    M. Wissel, Viracor Eurofins Clinical Diagnostics: Employee , Salary .

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.