First description of Lachnoanaerobaculum orale as a possible cause of human bacteremia

Anaerobe. 2022 Feb:73:102506. doi: 10.1016/j.anaerobe.2021.102506. Epub 2021 Dec 28.


Lachnoanaerobaculum spp. is an obligate anaerobic, gram-positive, spore-forming, rod-shaped bacillus. Here, we report the first known case of bacteremia due to L. orale, which was detected in a patient with acute lymphoblastic leukemia. A 69-year-old man developed neutropenic fever with severe stomatitis during chemotherapy for leukemia. The bacteria strain isolated from blood culture was successfully identified as L. orale via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Susceptibility testing revealed that the strains showed low minimum inhibitory concentrations (MICs) of beta-lactams, clindamycin, and metronidazole, but higher MICs of fluoroquinolones. The present case study indicates that Lachnoanaerobaculum can be a cause of human infection, including bloodstream infection.

Keywords: Anaerobe; Bacteremia; Lachnoanaerobaculum orale; MALDI-TOF MS.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Bacteremia* / diagnosis
  • Bacteremia* / drug therapy
  • Bacteremia* / microbiology
  • Blood Culture
  • Clostridiales*
  • Humans
  • Male
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods

Supplementary concepts

  • Lachnoanaerobaculum orale