Biochemical Test of Bacteroides fragilis

Biochemical Test of Bacteroides fragilis

Basic Characteristics Properties (Bacteroides fragilis)
Capsule Positive (+ve)
Catalase Positive (+ve)
Flagella Negative (-ve)
Gelatin Hydrolysis Weakly Positive (+ve)
Gram Staining Gram-negative (-ve)
Growth in Bile (20%) Positive (+ve)
Hemolysis Negative (-ve)
Indole Variable
Motility Negative (-ve)
Nitrate Reduction Negative (-ve)
Oxidase Variable
Pigment Negative (-ve)
Shape Rod-shaped cells with rounded ends.
Spore Negative (-ve)
Thioglycolate with bile Positive (+ve)
Urease Negative (-ve)

Fermentation of

Arabinose Negative (-ve)
Cellobiose Variable
Glucose Positive(+ve)
Glycogen Positive(+ve)
Inositol Negative (-ve)
Lactose Positive(+ve)
Maltose Positive(+ve)
Mannitol Negative (-ve)
Mannose Positive(+ve)
Melibiose Weakly Positive (+ve)
Raffinose Positive(+ve)
Rhamnose Negative (-ve)
Ribose Negative (-ve)
Salicin Negative (-ve)
Starch Positive (+ve)
Sucrose Positive (+ve)
Trehalose Negative (-ve)
Xylan Negative (-ve)
Xylose Positive (+ve)

Enzymatic Reactions

Alanine arylamidase Positive (+ve)
Esculin Hydrolysis Positive (+ve)
Glutamic acid decarboxylase Positive (+ve)
Glycine arylamidase Negative (-ve)
Leucine arylamidase Positive (+ve)
Leucyl glycine arylamidase Positive (+ve)
N-Acety1- b-glucosaminidase Positive (+ve)
ONPG (β-galactosidase) Positive (+ve)


  1. Editors: Krieg, N.R., Ludwig, W., Whitman, W., Hedlund, B.P., Paster, B.J., Staley, J.T., Ward, N., Brown, D., Parte, A. (2010). Bergey’s Manual of Systematic Bacteriology. Volume 4: The Bacteroidetes, Spirochaetes, Tenericutes (Mollicutes), Acidobacteria, Fibrobacteres, Fusobacteria, Dictyoglomi, Gemmatimonadetes, Lentisphaerae, Verrucomicrobia, Chlamydiae, and Planctomycetes.
  5. microbiology/bacteroides-fragilis
  6. Draper, D. L., & Barry, A. L. (1977). Rapid identification of Bacteroides fragilis with bile and antibiotic disks. Journal of clinical microbiology5(4), 439-43.

About Author

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Sagar Aryal

Sagar Aryal is a microbiologist and a scientific blogger. He is doing his Ph.D. at the Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal. He was awarded the DAAD Research Grant to conduct part of his Ph.D. research work for two years (2019-2021) at Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Saarbrucken, Germany. Sagar is interested in research on actinobacteria, myxobacteria, and natural products. He is the Research Head of the Department of Natural Products, Kathmandu Research Institute for Biological Sciences (KRIBS), Lalitpur, Nepal. Sagar has more than ten years of experience in blogging, content writing, and SEO. Sagar was awarded the SfAM Communications Award 2015: Professional Communicator Category from the Society for Applied Microbiology (Now: Applied Microbiology International), Cambridge, United Kingdom (UK).

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