I. TYPING METHODS FOR CLOSTRIDIUM
13
and faeces for lysogeny. Seventeen per cent of the strains were lysogenic,
but the host range of the phages was very narrow. In a later paper Hirano
and Imamura (1972b), examining 17 strains of known toxin types A to F,
found lysogeny in only types B, C and E. These results differ from Smith’s
(1959) indicating that lysogeny is not restricted to certain toxin types.
T h e potential of phage typing C. perfringens was shown by Imbert
(1968). With a battery of 15 phages isolated from sewer water, 85% of
181 strains of C. perfringens could be divided into 51 lysotypes. The most
frequent typing pattern represented 13% of the typable cultures, while
many of the typing patterns contained only one or two strains.
Hirano and Yonekura (1967) presented electron microscopy data on 15
free phages and 16 temperate phages. All virulent phages had a head
diameter of 40 nm and a contractile tail 30-40 nm long, while temperate
phages had much longer tail structures of 140-220 nm which were relatively
simple in design. A temperate phage of the latter morphology, described
by Mahony and Kalz (1968) exhibited a latent period of 45 min and a 17fold yield. Lysogenisation by this phage resulted in the production of an
increased number of heat resistant spores by the lysogenised strain and an
altered sporulation time (Stewart and Johnson, 1977). A second phage
(Mahony and Easterbrook, 1970) also showed a latent period of 45 min.
Head forms were visible intracellularly 30 min post-infection and tails by
35 min. Assembly seemed complete 40 min post-infection. In 1971, Bradley and Hoeniger noted structural changes in C. perfringens infected with a
short-tailed bacteriophage originally isolated by Vieu et ul. in 1965. Ionesco
et al. (1974) demonstrated a lag period of 50 min for phage induced by UV
light in a strain which was both lysogenic and bacteriocinogenic. Differences in the production of these two elements were described.
Yonekura et ul. (1972) described the isolation of 22 virulent bacteriophages of C. perfringens from sewage and concluded that the host ranges of
nine such phages were quite restricted. Some 50% of the strains were
resistant to any phage. T h e host range was variable partially due to hostinduced modification and other unexplained factors. These authors concluded that phage typing of C. perfringens was not feasible.
Imamura and Nakama (1974) tried to isolate phages of C. perfringens from
human intestinal contents and faeces but found phages in only three of
48 samples. These phages possessed the same morphology as that described
for temperate phages (Hirano and Yonekura, 1967). Four of 30 isolates of
C. perfringens were lysogenic and the morphologies of the phages carried
by these strains were similar to those of the temperate group. I n 1976,
Grant and Riemann described four temperate phages isolated from C.
perfringens type C which belonged to two classes. Three of the phages
were homoimmune and serologically related to the other phages. One was
13
and faeces for lysogeny. Seventeen per cent of the strains were lysogenic,
but the host range of the phages was very narrow. In a later paper Hirano
and Imamura (1972b), examining 17 strains of known toxin types A to F,
found lysogeny in only types B, C and E. These results differ from Smith’s
(1959) indicating that lysogeny is not restricted to certain toxin types.
T h e potential of phage typing C. perfringens was shown by Imbert
(1968). With a battery of 15 phages isolated from sewer water, 85% of
181 strains of C. perfringens could be divided into 51 lysotypes. The most
frequent typing pattern represented 13% of the typable cultures, while
many of the typing patterns contained only one or two strains.
Hirano and Yonekura (1967) presented electron microscopy data on 15
free phages and 16 temperate phages. All virulent phages had a head
diameter of 40 nm and a contractile tail 30-40 nm long, while temperate
phages had much longer tail structures of 140-220 nm which were relatively
simple in design. A temperate phage of the latter morphology, described
by Mahony and Kalz (1968) exhibited a latent period of 45 min and a 17fold yield. Lysogenisation by this phage resulted in the production of an
increased number of heat resistant spores by the lysogenised strain and an
altered sporulation time (Stewart and Johnson, 1977). A second phage
(Mahony and Easterbrook, 1970) also showed a latent period of 45 min.
Head forms were visible intracellularly 30 min post-infection and tails by
35 min. Assembly seemed complete 40 min post-infection. In 1971, Bradley and Hoeniger noted structural changes in C. perfringens infected with a
short-tailed bacteriophage originally isolated by Vieu et ul. in 1965. Ionesco
et al. (1974) demonstrated a lag period of 50 min for phage induced by UV
light in a strain which was both lysogenic and bacteriocinogenic. Differences in the production of these two elements were described.
Yonekura et ul. (1972) described the isolation of 22 virulent bacteriophages of C. perfringens from sewage and concluded that the host ranges of
nine such phages were quite restricted. Some 50% of the strains were
resistant to any phage. T h e host range was variable partially due to hostinduced modification and other unexplained factors. These authors concluded that phage typing of C. perfringens was not feasible.
Imamura and Nakama (1974) tried to isolate phages of C. perfringens from
human intestinal contents and faeces but found phages in only three of
48 samples. These phages possessed the same morphology as that described
for temperate phages (Hirano and Yonekura, 1967). Four of 30 isolates of
C. perfringens were lysogenic and the morphologies of the phages carried
by these strains were similar to those of the temperate group. I n 1976,
Grant and Riemann described four temperate phages isolated from C.
perfringens type C which belonged to two classes. Three of the phages
were homoimmune and serologically related to the other phages. One was