514
Antonie van Leeuwenhoek
13-Haemolysis by Streptococcus
45 (1979)
mutans
J. WOLTJES 1, D . M . M A C L A R E N 2 AND J. DE GRAAFF 1 Departments of Oral Microbiology 1 and Medical Microbiology 2, Schools o f Medicine and Dentistry, Free University, Amsterdam, The Netherlands
The pyogenic streptococci from the upper respiratory tract and the oral cavity have attracted considerable interest because of their pathogenic potential. The strains belonging to this group almost invariably are [3-haemolytic, producing haemolysins which have been related to their virulence (Wannamaker and Matsen, 1972). On the other hand, little attention has been paid to the incidence and the nature of haemolysis among other streptococci. [3-Haemolytic strains of Streptococcus mutans can be found in low frequency. We have studied 8 [3-haemolytic strains from the oral cavity. These strains formed acid from mannitol and sorbitol, produced dextrans from sucrose and formed clear haemolytic zones on blood agar plates. The haemolytic zones closely resembled the [3-haemolytic zones produced by the pyogenic streptococci. By using a modification of the method of Ginsburg, Harris and Grossowicz (1963) for the detection of streptolysin S, we were able to solubilize haemolytic activity from the cells of 6 S. mutans strains. The cells were incubated overnight in phosphate buffered saline containing maltose and Tween 80. After titration, haemolytic activity could be demonstrated ranging between 8 and 64 Units/ml depending on the strains tested. One Haemolytic Unit was defined as the amount that completely lysed a red cell suspension (final concentration, 0.5 ~ v/v) within 30 minutes at 37 °C. In contrast with streptolysin S from the pyogenic streptococci, the substitution of other detergents, of human serum or o f yeast R N A for Tween 80 (Ginsburg et al., 1963) did not result in solubilization of any haemolytic activity. On the other hand, maltose could be replaced by glucose without a change in haemolytic activity. Furthermore, the haemolytic activity from S. mutans cells was not affected by the addition of Mg ÷ +ions or cysteine. This Tween 80-dependent haemolytic activity remained unchanged after 30 minutes of incubation at 100 °C as well as after 30 minutes of incubation at pH 4 or pH 10. No haemolytic activity could be demonstrated in the supernatants of growing and stationary cultures of the haemolytic S. mutans strains. This observation is in contrast with the results of Wolff and Liljemark (1978), who reported the demonstration of a soluble haemolytic activity in the supernatants of haemolytic S. mutans cultures. Studies are in progress to characterize further this haemolytic activity ofS. mutans and to see whether this property contributes to the virulence of these strains. WANNAMAKER, L. W., and MATSEN, J. M. 1972. Streptococci and streptococcal diseases. - - Academic Press, New York and London. GINSBURG, I., HARRIS, T. N. and GROSSOWICZ, N. 1963. Oxygen-stable haemolysins of group A s t r e p t o c o c c i . - J. Exp. Med. 118: 905-917. WOLFF, L. and LILJEMARK,W. F. 1978. Observation of ~3-hemolysis among three strains of Streptococcus mutans. - - Infect. Immun. 19: 745-748.
Antonie van Leeuwenhoek
13-Haemolysis by Streptococcus
45 (1979)
mutans
J. WOLTJES 1, D . M . M A C L A R E N 2 AND J. DE GRAAFF 1 Departments of Oral Microbiology 1 and Medical Microbiology 2, Schools o f Medicine and Dentistry, Free University, Amsterdam, The Netherlands
The pyogenic streptococci from the upper respiratory tract and the oral cavity have attracted considerable interest because of their pathogenic potential. The strains belonging to this group almost invariably are [3-haemolytic, producing haemolysins which have been related to their virulence (Wannamaker and Matsen, 1972). On the other hand, little attention has been paid to the incidence and the nature of haemolysis among other streptococci. [3-Haemolytic strains of Streptococcus mutans can be found in low frequency. We have studied 8 [3-haemolytic strains from the oral cavity. These strains formed acid from mannitol and sorbitol, produced dextrans from sucrose and formed clear haemolytic zones on blood agar plates. The haemolytic zones closely resembled the [3-haemolytic zones produced by the pyogenic streptococci. By using a modification of the method of Ginsburg, Harris and Grossowicz (1963) for the detection of streptolysin S, we were able to solubilize haemolytic activity from the cells of 6 S. mutans strains. The cells were incubated overnight in phosphate buffered saline containing maltose and Tween 80. After titration, haemolytic activity could be demonstrated ranging between 8 and 64 Units/ml depending on the strains tested. One Haemolytic Unit was defined as the amount that completely lysed a red cell suspension (final concentration, 0.5 ~ v/v) within 30 minutes at 37 °C. In contrast with streptolysin S from the pyogenic streptococci, the substitution of other detergents, of human serum or o f yeast R N A for Tween 80 (Ginsburg et al., 1963) did not result in solubilization of any haemolytic activity. On the other hand, maltose could be replaced by glucose without a change in haemolytic activity. Furthermore, the haemolytic activity from S. mutans cells was not affected by the addition of Mg ÷ +ions or cysteine. This Tween 80-dependent haemolytic activity remained unchanged after 30 minutes of incubation at 100 °C as well as after 30 minutes of incubation at pH 4 or pH 10. No haemolytic activity could be demonstrated in the supernatants of growing and stationary cultures of the haemolytic S. mutans strains. This observation is in contrast with the results of Wolff and Liljemark (1978), who reported the demonstration of a soluble haemolytic activity in the supernatants of haemolytic S. mutans cultures. Studies are in progress to characterize further this haemolytic activity ofS. mutans and to see whether this property contributes to the virulence of these strains. WANNAMAKER, L. W., and MATSEN, J. M. 1972. Streptococci and streptococcal diseases. - - Academic Press, New York and London. GINSBURG, I., HARRIS, T. N. and GROSSOWICZ, N. 1963. Oxygen-stable haemolysins of group A s t r e p t o c o c c i . - J. Exp. Med. 118: 905-917. WOLFF, L. and LILJEMARK,W. F. 1978. Observation of ~3-hemolysis among three strains of Streptococcus mutans. - - Infect. Immun. 19: 745-748.
