1444 - Characterization of a Novel Pathogen in Immunocompromised Patients: Elizabethkingia Anopheles

Background: A 60-year-old woman with acute myeloid leukemia developed fever and cough post induction chemotherapy. Meropenem and vancomycin were administered as empiric therapy. A bloodstream infection due to resistant E. meningoseptica was initially identified. Ceftazidime-avibactam and aztreonam (ATM) were next administered. Minocycline and trimethoprim/sulfamethoxazole (TMP/SMX) were added as the patient deteriorated and died ten days later.

Methods: MIC testing /disc diffusion assays were done according to CLSI guidelines. Whole genome sequencing (WGS) was performed, assembled, and annotated using PATRIC.org and compared to Institute Pasteur cgMLST instance of the BIGSdb database tool. Resistant genes and plasmids were identified by the Center for Genomic epidemiology.

Results: Core genome MLST and average nucleotide identity of 99.46% revealed the organism as E. anophelis, not E. meningoseptica. The WGS assembly resulted in 118 contigs with a chromosome of 4,110,726 bp. Plasmids were not identified. Resistance genes bla_B11, bla_GOB-13 (a metallo beta-lactamase) and bla_CME-1 were detected. E. anophelis was resistant to multiple drug classes including aminoglycosides, vancomycin, cephalosporins, and carbapenems. Mechanism based susceptibility testing using double-disc diffusion assays demonstrated susceptibility to cefiderocol (MIC 1 µg/ml), minocycline, TMP/SMX, linezolid, and modestly wider zones of inhibition with the addition of ATM. Susceptibility results are shown in Table 1.Antimicrobial susceptibility testing using various BLIs and combinations with Aztreonam


Conclusion: This is one of the first reports describing E. anophelis in immunocompromised hosts. More thorough testing methods are needed for distinguishing between species in the Elizabethkingia genus in hospital settings as there is concern that this may represent a novel opportunistic infection. Per CDC, E. anophelis outbreaks have occurred in three Midwestern states in 2016. Vigilance is warranted to the role of this pathogen in immunocompromised hosts.