IV. INVESTIGATION OF C . DIPHTHERIAE
107
typing as an independent marker to subdivide phage types and serotypes
respectively. Strains which were untypable by other methods were also
classified.
Zamiri and McEntegart (1973) and Toshach et al. (1972) used this method
successfully for the classification of untypable C . diphtheriae strains.
Meitert (1972, 1975) uses the contact method described by Hamon
(1965) and adapted by her to the growth requirements of C . diphtheriae. She
proposed a bacteriocin typing scheme permitting the classification of
different sensitivity patterns of the strains, against a set of 20 bacteriocin
producers selected from among different Corynebacterium species namely :
14 C . diphtheriae strains, one C . ulcerans, four C . hofmannii and one C .
xerosis strain.
Rurka (1974) devised a technique whereby producer strains were grown
on a quadrant of filter paper placed on the culture medium surface. The
bacteriocins would diffuse through this paper which was then removed and
the indicator strains applied with a multipoint applicator. This modification allowed all indicator strains to be applied in a single operation.
Following the typing of 588 Canadian strains, and 64 other C . diphtheriae
strains from different countries (U.S.A., England) the method was found
to be reproducible, but still of limited value. Only 24.4% of the strains
examined were typable and 86-8y0 of the typable strains were of the same
type.
The bacteriocin typing scheme proposed by Meitert (1975) contains
16 bacteriocin groups A-P, 12 of which are subdivided into types specified
by Arabic numerals (Fig. 20a, b). Most of the 1171 C . diphtheriae and
C . ulcerans strains, isolated chiefly from carriers between 1969 and 1972,
proved to belong to bacteriocin group A (69.5%). The rest belonged to
other bacteriocin groups: E, G, F, D, B, I, C, H, P, 0, L, N, J, K and M.
According to Meitert, the bacteriocin type is not concordant either with
the biotype or species C . diphtheriae, for example, the same bacteriocin
type may include gravis, mitis or intermedius strains of C . diphtheriae and
even C . ulcerans. However a correlation could be observed by the authors
between a certain bacteriocin type and phage type in the case of strains
isolated at a given moment and in a certain community.
Gibson and Colman (1973), using Gillies’s bacteriocin typing technique
(1964), found a correlation between bacteriocin type and phage-, sero-, and
biotype.
2. C. diphtheriae bacteriocin typing scheme
The bacteriocin typing scheme, established by Meitert (1972, 1973)
(Fig. 20) is based upon determination of the sensitivity of strains tested
against a set of 20 constant bacteriocin producer strains, labelled 1-20.
107
typing as an independent marker to subdivide phage types and serotypes
respectively. Strains which were untypable by other methods were also
classified.
Zamiri and McEntegart (1973) and Toshach et al. (1972) used this method
successfully for the classification of untypable C . diphtheriae strains.
Meitert (1972, 1975) uses the contact method described by Hamon
(1965) and adapted by her to the growth requirements of C . diphtheriae. She
proposed a bacteriocin typing scheme permitting the classification of
different sensitivity patterns of the strains, against a set of 20 bacteriocin
producers selected from among different Corynebacterium species namely :
14 C . diphtheriae strains, one C . ulcerans, four C . hofmannii and one C .
xerosis strain.
Rurka (1974) devised a technique whereby producer strains were grown
on a quadrant of filter paper placed on the culture medium surface. The
bacteriocins would diffuse through this paper which was then removed and
the indicator strains applied with a multipoint applicator. This modification allowed all indicator strains to be applied in a single operation.
Following the typing of 588 Canadian strains, and 64 other C . diphtheriae
strains from different countries (U.S.A., England) the method was found
to be reproducible, but still of limited value. Only 24.4% of the strains
examined were typable and 86-8y0 of the typable strains were of the same
type.
The bacteriocin typing scheme proposed by Meitert (1975) contains
16 bacteriocin groups A-P, 12 of which are subdivided into types specified
by Arabic numerals (Fig. 20a, b). Most of the 1171 C . diphtheriae and
C . ulcerans strains, isolated chiefly from carriers between 1969 and 1972,
proved to belong to bacteriocin group A (69.5%). The rest belonged to
other bacteriocin groups: E, G, F, D, B, I, C, H, P, 0, L, N, J, K and M.
According to Meitert, the bacteriocin type is not concordant either with
the biotype or species C . diphtheriae, for example, the same bacteriocin
type may include gravis, mitis or intermedius strains of C . diphtheriae and
even C . ulcerans. However a correlation could be observed by the authors
between a certain bacteriocin type and phage type in the case of strains
isolated at a given moment and in a certain community.
Gibson and Colman (1973), using Gillies’s bacteriocin typing technique
(1964), found a correlation between bacteriocin type and phage-, sero-, and
biotype.
2. C. diphtheriae bacteriocin typing scheme
The bacteriocin typing scheme, established by Meitert (1972, 1973)
(Fig. 20) is based upon determination of the sensitivity of strains tested
against a set of 20 constant bacteriocin producer strains, labelled 1-20.