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[Presence of plasmids in Neisseria meningitidis]
Abstract:
The plasmid content of twenty-nine Neisseria meningitidis strains, isolated from CSF and blood cultures, was investigated by agarose gel electrophoresis. The strains (twenty-seven from serogroup B and two from serogroup C) were sensitive to antibiotics, but 50% were resistant to sulphonamide (MIC greater than or equal to 16 mg/l). Two serogroup-B strains from CSF harboured an extrachromosomal element. These two cryptic plasmids differed in size: 8.4 Kb for pNMT1 and 82 Kb for pNMT2.
Insights
Agarose gel electrophoresis revealed that two Neisseria meningitidis serogroup B strains from cerebrospinal fluid harbored distinct cryptic plasmids, pNMT1 (8.4 Kb) and pNMT2 (82 Kb). Fifty percent of the strains showed sulphonamide resistance.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Neisseria meningitidis is a significant bacterial pathogen.
- Understanding meningococcal plasmid content is crucial for tracking antibiotic resistance.
- Previous studies have characterized various meningococcal plasmids.
Purpose of the Study:
- To investigate the plasmid content of Neisseria meningitidis strains isolated from clinical samples.
- To identify and characterize any extrachromosomal elements present in these strains.
- To assess the antibiotic resistance profiles, particularly to sulphonamide, in conjunction with plasmid carriage.
Main Methods:
- Agarose gel electrophoresis was used to analyze plasmid DNA.
- Neisseria meningitidis strains were isolated from cerebrospinal fluid (CSF) and blood cultures.
- Minimum Inhibitory Concentration (MIC) testing was performed for antibiotic susceptibility, specifically for sulphonamide.
Main Results:
- Twenty-nine Neisseria meningitidis strains (27 serogroup B, 2 serogroup C) were analyzed.
- Fifty percent of the strains exhibited resistance to sulphonamide (MIC ≥ 16 mg/l).
- Two serogroup B strains isolated from CSF contained extrachromosomal DNA elements, identified as cryptic plasmids pNMT1 (8.4 Kb) and pNMT2 (82 Kb).
Conclusions:
- The presence of distinct cryptic plasmids (pNMT1 and pNMT2) in Neisseria meningitidis strains was confirmed.
- A significant proportion of the investigated strains displayed sulphonamide resistance.
- Further research is warranted to understand the role of these plasmids in meningococcal pathogenicity and antibiotic resistance.