Isolation ofFusobacterium nucleatumfrom human feces using immunomagnetic separation coupled with fastidious anaerobe agar

Abstract

Aim Fusobacterium nucleatum (F. nucleatum) is associated with the initiation, development, and metastasis of colorectal cancer. However, it is difficult to isolate F. nucleatum from clinical specimens. In this study, we aimed to develop an effective and rapid method for isolating F. nucleatum from human feces using polyclonal antibody (PAB)-coated immunomagnetic beads (IMBs) with selective media. Methods and results IMBs conjugated with PAB were prepared and used to isolate F. nucleatum from human feces, and the bacteria were cultured with selective culture media (fastidious anaerobe agar + nalidixic acid + vancomycin). Under optimized experimental conditions, IMBs could selectively recover F. nucleatum from fecal microbiota samples spiked with Peptostreptococcus or Bacteroides fragilis. In artificial fecal samples, the detection sensitivity of IMBs for F. nucleatum was 103 CFU mL−1. In addition, IMBs combined with selective media could rapidly isolate F. nucleatum from human feces. Conclusions This study successfully established an effective method for the rapid isolation of F. nucleatum from human feces by IMBs. The whole procedure requires 2–3 days, and has a sensitivity of 103 CFU mL−1 feces.

Screening for colorectal cancer: Study on the shedding cells of feces

“…[ 22 ] These limitations have been overcome by a methodology combining whole-feces elution and immunomagnetic beads to extract fecal exfoliated cells, allowing observation of the exfoliated intact cells from feces, and has been applied to the research of other colorectal cancer-related analytical markers. [ 23 ] However, the cell enrichment rate was still low, and a large number of enriched cells were squamous epithelial cells exfoliated from the anal canal. [ 24 ] Nanomagnetic materials are nanoscale particles with a diameter of about 1–100 nm possessing unique magnetic and quantum size effects.…”