Microbiological and Clinical Significance of a New Property of Defective Lysis in Clinical Strains of Pneumococci

Differences of Pathophysiology in Experimental Meningitis Caused by Three Strains of Streptococcus Pneumoniae

“…Our results with the cell-wall fractions and previous studies with similar preparations indicate that the bacterial cell wall could play a role in mediating disease in pneumococcal infections [20,39,40]. Similar to endotoxin in the case of gramnegative organisms, cell-wall fragments can induce the release of interleukin-l, and to a lesser extent cachectin, from mononuclear cells [41].…”

“…All strains were sensitive to penicillin (MIC~0.03 mg/l). Strains A and B exhibited a classic lysis-sensitive response to penicillin (>60 %reduction in turbidity at 4 h), while the response of strain C to penicillin paralleled that of a lysis-defective strain lyt 4-4 «20% reduction of turbidity at 4 h) [20].…”

“…Capsular expression was stable in vitro and after passage through rabbits. In vitro doubling times in Todd-Hewitt broth were 27 min for strain A and 33 min for strains Band C. Spontaneous release ofteichoicated cellwall material in vitro was estimated by prelabeling the teichoic acid and lipoteichoic acid of the pneumococcal cell surfaces with 1 11-Cit ml [3H]choline (Amersham Radiochemicals, Arlington Heights, IL) for 6 h, growing the strains in unlabeled medium for 2 h, and then measuring [3H]choline in cell wall precipitated in boiling SDS [20].…”

“…During logarithmic growth in a semisynthetic medium, C + Y [20], release of [3H]choline was on the order of only 4 %-5 % per generation for strains Band C, while strain A lost 12 % per generation.…”

“…Pneumococcal cell wall induces CSF inflammation [21,27], and it has been proposed that the amount and composition of cell-wall fractions released from infecting strains could modulate some aspects of meningitis [20]. We therefore examined the abili- 5.3 ± 3.4 91.3 ± 9.9t 7.56 ± 0.11:1:…”