Clostridium oedematiens (Clostridium novyi) is an anaerobic spore
forming bacillus. The organism is an important pathogen of sheep
and cattle, and can be responsible for gas gangrene in humans. Four
tykes designated A, B, C and D are recognised on the basis of serological neutralisation tests. Cl. oedematiens is generally regarded
as being very difficult to handle in the laboratory; thus, the recent
introduction of a commercially available fluorescent globulin for the
identification of this organism has encouraged. workers to disregard
the necessity for confirmatory isolation and typing procedures.
Reliable techniques for the isolation and subculture of Ci. oedematiens
are an essential prerequisite for a study of the occurrence
of this organism, and my initial work soon confirmed that type B, C
and D strains of Cl. oedematiens are Lifficul.t to subculture with
confidence on solid media. It became clear that much preliminary
laboratory work is necessary before a field investigation could yield
The writer considered that the irregular growth of this organism
on solid media might be related to (i) failures in the anaerobic
environment; (ii) a requirement for a particularly complex nutritional
medium; or (iii) the viability of the inoculu'E and each of
these variables is carefully studied in the present work. The first
part describes a reappraisal of the technique for setting up a modern anaerobic jar. Variations in the technique are assessed, and it is
concluded that the irregular growth of these strains is not necessarily
related to faults in normal anaerobic procedure.
A variety of culture media are tested for the ability to support
regular growth of Cl. oedematiens. The aim. of these experiments is
to determine whether the organism crows better on complex media than
on relatively simple media; it is found that irregular growth occurs
on both types of media.
The viability of a number of different inocula are studied in
order to test the assumption that an inoculum containing spores shoul
be viable. The results of these experiments are compatible with the
view that consistent growth of Cl. oedematiens on solid media may be
related to the spore content of the inoculum; however, it is likely
that other factors are involved, and a theory is developed that a low
redox potential in the mioroenvironment is also necessary for the
successful outgrowth of viable particles.
The epidemiological distribution of this organism can be assessed
only if adequate descriptions and techniques of identification are
available. Thus, the characters of the Cl. oedematiens group are
confirmed and extended during the present work. These studies inelude
(i) a critical evaluation of the fluorescent staining procedure
(ii) a reappraisal of the fermentation reactions of the group;
(iii) an assessment of the value of solid indicator media in the
identification of this organism; (iv) an intensive study of the soluble products of Cl. oedematiens; and (v) the development of a practical system of typing with cultures grown in cooked-meet medium.
The soluble products of the organism are investigated in various
types of media, and particular attention is paid to the production of
the factors that are responsible for the pathogenic effects in-vivo.
Culture products of Ci. oedematiens are fractionated and it is found
that the biological activities are readily separated. by Orel-filtration
procedures. A thin-layer chromatographic technique is developed in
an attempt to identify more precisely the factors that affect egg -
yolk emulsion. A cytopathic effect that is produced by the soluble
products of Cl. oedematiens is investigated, and is provisionally
attributed to the presence of the alpha antigen.
The experimental observations are discussed in relation to our
present knowledge of Cl. oede .atiens e d future lines of research are