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A study of pathogenic factors of Streptococcus pneumoniae strains causing meningitis
N N Kostyukova1, M O Volkova, V V Ivanova
1Gamaleya Institute of Epidemiology and Microbiology of Russian Academy of Medical Sciences, Moscow.
Abstract:
Pneumococcal meningitis in St. Petersburg in the period 1985-1991 occurred in 1.7-2.3 children per 100,000 annually. The most common serotypes among pneumococcal strains isolated from patients with meningitis were 19, 1, 6, 15, and 2, whereas, among the capsulated strains isolated from carriers, type 3 predominated. Only one third of strains from cases of meningitis were highly virulent for mice (types 1, 2, 3). Hyaluronidase 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 (11.5 +/- 2.8%) out of 130 strains isolated from carriers. Non-capsulated strains lacked this enzyme. Results of intranasal inoculation of pneumococcal strains with different hyaluronidase activity and addition of exogenous hyaluronidase to strains which did not produce the enzyme confirm the hypothesis that this enzyme plays an important role in bacterial dissemination and breaching of the blood brain barrier by pneumococci. It was concluded that high hyaluronidase activity, presence of capsule, and pneumolysin or serotype (1, 2, and 19) despite hyaluronidase titer, are the most important factors contributing to the development of pneumococcal meningitis. The role of the mouse toxic factor is unclear.
Insights
Pneumococcal meningitis is linked to specific bacterial factors like hyaluronidase and capsule presence. These elements, along with certain serotypes, are key in developing this serious infection in children.
Area of Science:
- Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Pneumococcal meningitis incidence in St. Petersburg (1985-1991) was 1.7-2.3 cases per 100,000 children annually.
- Common serotypes in meningitis cases included 19, 1, 6, 15, and 2.
- Serotype 3 predominated in capsulated strains from carriers.
Purpose of the Study:
- To investigate the role of hyaluronidase in pneumococcal meningitis development.
- To identify key factors contributing to the pathogenesis of pneumococcal meningitis.
Main Methods:
- Analysis of pneumococcal strains isolated from meningitis patients and carriers.
- Assessment of hyaluronidase production by different strains.
- Intranasal inoculation studies in mice with varying hyaluronidase activity.
Main Results:
- Hyaluronidase was produced by all strains from meningitis and otitis media patients, but by only 11.5% of strains from carriers.
- Non-capsulated strains lacked hyaluronidase.
- Studies confirmed hyaluronidase's role in bacterial spread and crossing the blood-brain barrier.
Conclusions:
- High hyaluronidase activity, capsule presence, and pneumolysin are crucial for pneumococcal meningitis.
- Specific serotypes (1, 2, 19) are significant, irrespective of hyaluronidase levels.
- The role of mouse toxic factor in meningitis pathogenesis remains undetermined.