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[The drug sensitivity of meningococci and the characteristics of its determination]
Abstract:
The results obtained in the study of antibiotic and sulfamide sensitivity of 197 Neisseria meningitidis strains of groups A, B and C, isolated from the spinal fluid and blood of patients with meningococcal infection hospitalized in the 2nd Clinico-Infectious Hospital, Moscow, in 1984-1989 and studied with the use of the disc diffusion method and the method of serial dilutions of antibiotics in solid culture media, are presented. As revealed in this study, N. meningitidis strains retained their high sensitivity to penicillin and ampicillin (MIC50 = 0.016 and 0.032 micrograms/ml respectively). Sensitivity to tetracycline decreased (MIC50 = 0.5 micrograms/ml) and to rifampicin increased (MIC50 = 0.063 micrograms/ml). 48.5% of strains were resistant to streptomycin. In recent years the proportion of N. meningitidis, resistant to sulfanilamide preparations, significantly decreased and MIC50 was equal to 2.5 micrograms/ml in comparison with 5-10 micrograms/ml in the preceding period. The results of testing sensitivity to antibiotics by both methods coincided. Still the disc diffusion method can be used in epidemiological surveillance on meningococcal infection, while for more exact differentiation of N. meningitidis strains the use of the method of serial dilutions is necessary.
Insights
Neisseria meningitidis strains show high sensitivity to penicillin and ampicillin. Antibiotic resistance patterns evolved, with decreased resistance to sulfanilamides and increased resistance to streptomycin observed in meningococcal infection cases.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Meningococcal infection poses a significant public health challenge.
- Understanding Neisseria meningitidis antibiotic sensitivity is crucial for effective treatment and surveillance.
- Changes in antimicrobial resistance patterns necessitate ongoing monitoring.
Purpose of the Study:
- To evaluate the antibiotic and sulfamide sensitivity of Neisseria meningitidis strains.
- To analyze trends in antimicrobial resistance over time.
- To compare the efficacy of disc diffusion and serial dilution methods for sensitivity testing.
Main Methods:
- The study analyzed 197 Neisseria meningitidis strains (groups A, B, C) isolated from patients with meningococcal infection.
- Antibiotic sensitivity was determined using the disc diffusion method and serial dilutions in solid culture media.
- Minimum Inhibitory Concentration 50 (MIC50) values were calculated for various antibiotics and sulfamides.
Main Results:
- Neisseria meningitidis strains maintained high sensitivity to penicillin and ampicillin (MIC50 = 0.016 and 0.032 µg/ml).
- Sensitivity decreased for tetracycline (MIC50 = 0.5 µg/ml) and increased for rifampicin (MIC50 = 0.063 µg/ml).
- 48.5% of strains were resistant to streptomycin, and resistance to sulfanilamide preparations significantly decreased (MIC50 = 2.5 µg/ml).
Conclusions:
- Neisseria meningitidis retains sensitivity to penicillin and ampicillin, but resistance patterns are evolving.
- The disc diffusion method is suitable for epidemiological surveillance, while serial dilutions offer more precise differentiation.
- Continuous monitoring of antimicrobial susceptibility is essential for managing meningococcal infections effectively.