IV. INVESTIGATION OF C. DIPHTHERIAE
95
phage typingcentre of Wernigerode(Endemann 1960; Kische andEndemann,
1962). The typing phages are arranged in order and grouped according to
their lytic activity against the three biotypes, mitis, intermedius and gravis.
The first group of typing phages contains the 1-6 phage preparations
which are active against the mitis type strains; the second from 7 and 8 are
active on intermedius and gravis tox- and 9 attacks only intermedius
strains. All phage preparations from position 10-22 possess lytic properties
againstgravis type strains. Only two of thegravis phages, i.e. nos 10 and 16,
show sporadic and very weak reactions against two of the mitis reference
strains C. diphtheriae 192 and 1180 (phage types Ia and 11).
The number of gravis typing phages from the basic set is outstanding
(Fig. 8). This is explained by the prevalence and large variety of gravis
type strains in Romania, during the time this scheme was developed.
3 . Phage sensitive (indicator) strains
The vertical rows on the left of the scheme (Fig. 8) include the phagesensitive strains (prototypes of the different phage types) arranged in
order and grouped according to the biotype to which they belong. Each
phage type is characterised by one, two or more specific lytic reactions,
grouped according to a certain “lytic pattern”. The second, third and
fourth vertical rows record the number, origin and biotype to which the
strains belong. Their toxinogenic properties are also shown. For each
phage type, one or more sensitive strains of different geographical origin
are recorded. Each phage type is designated by a Roman numeral in the
right vertical row.
Thus, with the help of the 22 typing phages, biotype mitis strains can be
divided into four phage types: I, Ia, I1 and 111; intermedius strains into
three types: IV, V, VI; and gravis strains into 14 types, called for convenience, VII, VIII, VIII “a”, IX, XIV, XIV “a”, XIV “b”, XIV “c”,
XVI, XII, XIII, XIII “a”, XVII and XIX. The strict relationship
between phage type and the biotype of each individual strain is remarkable.
An exception is that of phage type VI, which, may characterise either
gravis, or intermedius tox+ or tox-. It is worthy of note that, besides the
well-established “lytic patterns” presented by this scheme there are
a number of mitis and intermedius C. diphtheriae strains which are irregularly sensitive against some phages, irrespective of the biotype specificity of the phages.
Such strains were called “allosensitive”. They are infrequent.
4. Properties of the orkina1 phage typing scheme
The principal properties of a good typing system are the following:
95
phage typingcentre of Wernigerode(Endemann 1960; Kische andEndemann,
1962). The typing phages are arranged in order and grouped according to
their lytic activity against the three biotypes, mitis, intermedius and gravis.
The first group of typing phages contains the 1-6 phage preparations
which are active against the mitis type strains; the second from 7 and 8 are
active on intermedius and gravis tox- and 9 attacks only intermedius
strains. All phage preparations from position 10-22 possess lytic properties
againstgravis type strains. Only two of thegravis phages, i.e. nos 10 and 16,
show sporadic and very weak reactions against two of the mitis reference
strains C. diphtheriae 192 and 1180 (phage types Ia and 11).
The number of gravis typing phages from the basic set is outstanding
(Fig. 8). This is explained by the prevalence and large variety of gravis
type strains in Romania, during the time this scheme was developed.
3 . Phage sensitive (indicator) strains
The vertical rows on the left of the scheme (Fig. 8) include the phagesensitive strains (prototypes of the different phage types) arranged in
order and grouped according to the biotype to which they belong. Each
phage type is characterised by one, two or more specific lytic reactions,
grouped according to a certain “lytic pattern”. The second, third and
fourth vertical rows record the number, origin and biotype to which the
strains belong. Their toxinogenic properties are also shown. For each
phage type, one or more sensitive strains of different geographical origin
are recorded. Each phage type is designated by a Roman numeral in the
right vertical row.
Thus, with the help of the 22 typing phages, biotype mitis strains can be
divided into four phage types: I, Ia, I1 and 111; intermedius strains into
three types: IV, V, VI; and gravis strains into 14 types, called for convenience, VII, VIII, VIII “a”, IX, XIV, XIV “a”, XIV “b”, XIV “c”,
XVI, XII, XIII, XIII “a”, XVII and XIX. The strict relationship
between phage type and the biotype of each individual strain is remarkable.
An exception is that of phage type VI, which, may characterise either
gravis, or intermedius tox+ or tox-. It is worthy of note that, besides the
well-established “lytic patterns” presented by this scheme there are
a number of mitis and intermedius C. diphtheriae strains which are irregularly sensitive against some phages, irrespective of the biotype specificity of the phages.
Such strains were called “allosensitive”. They are infrequent.
4. Properties of the orkina1 phage typing scheme
The principal properties of a good typing system are the following: