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Genetic diversity of penicillin-resistant Neisseria meningitidis
J Campos1, M C Fusté, G Trujillo
1Department of Microbiology, Hospital de Sant Joan de Deu, Barcelona, Spain.
Abstract:
The genetic relatedness of 42 penicillin-resistant Neisseria meningitidis isolates obtained during a 2-year period from a single hospital was studied by multilocus enzyme electrophoresis and by restriction fragment length polymorphism (RFLP) analysis of penicillin-binding protein (PBP) 2 genes. The PBP 2 genes of 7 susceptible strains gave identical RFLP profiles. Sixteen different PBP 2 RFLP profiles were found among the 42 resistant strains, but 4 were found in greater than 1 resistant isolate. Multilocus enzyme electrophoresis revealed a high level of genetic diversity. Four clusters of resistant strains could be distinguished at a genetic distance of 0.75. Resistant strains with the most common PBP 2 RFLP profile were restricted to one of these clusters and may be derived from a common ancestral strain. However, resistant strains with the 3 other common RFLP profiles were distributed in two or more of the clusters.
Insights
Genetic analysis of penicillin-resistant Neisseria meningitidis reveals high diversity. While some resistant strains may share a common ancestor, most exhibit varied genetic profiles, indicating complex evolutionary pathways.
Area of Science:
- Microbiology
- Genetics
- Epidemiology
Background:
- Penicillin resistance in Neisseria meningitidis poses a significant public health concern.
- Understanding the genetic relatedness of resistant strains is crucial for tracking outbreaks and informing treatment strategies.
Purpose of the Study:
- To investigate the genetic diversity and relatedness of 42 penicillin-resistant Neisseria meningitidis isolates from a single hospital over two years.
- To differentiate between susceptible and resistant strains using genetic markers.
Main Methods:
- Multilocus enzyme electrophoresis (MEE) was employed to assess overall genetic diversity.
- Restriction fragment length polymorphism (RFLP) analysis of penicillin-binding protein (PBP) 2 genes was used to examine specific genetic variations.
Main Results:
- Penicillin-susceptible strains showed identical PBP 2 RFLP profiles.
- Sixteen distinct PBP 2 RFLP profiles were identified among the 42 resistant isolates.
- MEE revealed significant genetic diversity, with four main clusters of resistant strains identified.
- While one common PBP 2 RFLP profile was linked to a single cluster, suggesting a common ancestor, other common profiles were spread across multiple clusters.
Conclusions:
- Neisseria meningitidis exhibits substantial genetic diversity, even within isolates from a single hospital.
- The genetic makeup of penicillin-resistant strains is complex, with evidence of both common ancestry and independent evolution.
- Further research is needed to fully elucidate the evolutionary dynamics of antimicrobial resistance in Neisseria meningitidis.