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[Epidemiological evaluation of the serological grouping of meningococci]
Abstract:
Use of the precipitation and hemagglutination inhibition tests to determine the serological group of 114 meningococcus strains which cannot be grouped by agglutination slide permitted to establish the serological group of 56% of the strains, this pointing to the greater diagnostic value of these tests. Nevertheless, 70% of 307 strains isolated from carriers could not be referred to any of the determinable groups (A, C, X, Y, and Z). Strains (417) isolated from the cerebrospinal fluid of patients with meningitis were grouped depending on the epidemic curve: only half of the cultures could be classified in sporadic cases, but from 80 to 100% of the strains were classified at the "peak" of the meningitis incidence rise. This rise was connected with increase of the incidence of cases caused by meningococcus, group A; at the decline these strains were eliminated, and cases due to the rarely encountered serological groups and nongrouping strains occurred. Marking meningococc by serological groups proved to be of no use for detection of epidemiological relations between the infected persons.
Insights
Precipitation and hemagglutination inhibition tests improve meningococcus serological grouping. However, many strains from carriers and meningitis patients remain unclassified, limiting their use in tracking disease spread.
Area of Science:
- Microbiology
- Epidemiology
- Immunology
Background:
- Accurate serological grouping of Neisseria meningitidis is crucial for understanding meningitis epidemiology.
- Traditional agglutination methods have limitations in classifying all meningococcal strains.
- The diagnostic value of precipitation and hemagglutination inhibition tests for meningococcal serogrouping requires evaluation.
Purpose of the Study:
- To assess the efficacy of precipitation and hemagglutination inhibition tests in serologically grouping meningococcus strains.
- To determine the proportion of meningococcal strains from carriers and meningitis patients that can be serologically classified.
- To investigate the relationship between meningococcal serogroups and meningitis epidemic dynamics.
Main Methods:
- Serological grouping of 114 meningococcus strains using precipitation and hemagglutination inhibition tests.
- Analysis of 307 meningococcal strains isolated from carriers for group classification.
- Grouping of 417 meningococcal strains from cerebrospinal fluid based on epidemic curves.
Main Results:
- Precipitation and hemagglutination inhibition tests successfully serogrouped 56% of previously unclassifiable meningococcus strains.
- 70% of strains from carriers and approximately 50% of strains from sporadic meningitis cases could not be assigned to known groups (A, C, X, Y, Z).
- During meningitis peaks, 80-100% of strains were classifiable, with Group A dominating; during declines, unclassifiable strains and rare serogroups increased.
Conclusions:
- Precipitation and hemagglutination inhibition tests offer improved diagnostic value for meningococcal serogrouping compared to slide agglutination.
- A significant proportion of meningococcal strains, particularly from carriers, remain unclassifiable by current serological methods.
- Serogrouping meningococci has limited utility in establishing direct epidemiological links between infected individuals due to the high number of unclassified strains.