A STUDY OF PATHOGENIC FACTORS OF STREPTOCOCCUS-PNEUMONIAE STRAINS CAUSING MENINGITIS

Pneumococcal meningitis in St. Petersburg in the period 1985-1991 occu rred in 1.7-2.3 children per 100000 annually. The most common serotype s among pneumococcal strains isolated from patients with meningitis we re 19, 1, 6, 15, and 2, whereas, among the capsulated strains isolated from carriers, type 3 predominated. Only one third of strains from ca ses of meningitis were highly virulent for mice (types 1, 2, 3). Hyalu ronidase was produced by all the 39 studied strains, 22 (84.6 +/- 7.1% ) out of 26 strains from patients with otitis media, and only by 15 (1 1.5 +/- 2.8%) out of 130 strains isolated from carriers. Non-capsulate d strains lacked this enzyme. Results of intranasal inoculation of pne umococcal strains with different hyaluronidase activity and addition o f exogenous hyaluronidase to strains which did not produce the enzyme confirm the hypothesis that this enzyme plays an important role in bac terial dissemination and breaching of the blood brain barrier by pneum ococci. It was concluded that high hyaluronidase activity, presence of capsule, and pneumolysin or serotype (1, 2, and 19) despite hyaluroni dase titer, are the most important factors contributing to the develop ment of pneumococcal meningitis. The role of the mouse toxic factor is unclear.