The Journal of Medical Microbiology, Vol 14, Issue 1 63-76, Copyright © 1981 by Society for General Microbiology
Neuraminidase production by Bacteroidaceae
A. G. Fraser and R. Brown
The production of neuraminidase (EC 3.2.1.18) by 77 strains of
Bacteroidaceae was investigated by techniques previously used to study
neuraminidase production by clostridia. Conditions for culture and assay of
Bacteroides fragilis neuraminidase were characterised. The enzyme is
predominantly cell associated; it is not calcium dependent and the pH
optimum for its production is c. 4.5. Most neuraminidase-positive
Bacteroides strains produced the enzyme well in the test media but a few
strains failed to produce it consistently in one or other of the media.
Because of these occasional variations, strains were grown and tested in at
least two media before being defined as neuraminidase negative. Within the
B. fragilis group of species, B. fragilis, B. vulgatus, B. distasonis, B.
ovatus, B. thetaiotaomicron and B. variabilis were neuraminidase positive
while B. eggerthii, B. uniformis and B. splanchnicus were negative. Two
subspecies of B. melaninogenicus (ss. melaninogenicus and ss. levii) were
positive but the other (ss. intermedius) was negative. Strains of B. oralis
and B. bivius produced the enzyme while B. ruminicola, B. disiens, B.
asaccharolyticus and B. corrodens did not. The microaerophilic B. ochraceus
were also positive. None of the Fusobacterium or Leptotrichia species
tested produced neuraminidase. Our results for neuraminidase production are
consistent for all strains of each species examined and we suggest that
tests for neuraminidase production would be a valuable addition to
biochemical tests currently used in taxonomic studies of the
Bacteroidaceae.
