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Moderate resistance to penicillin in Neisseria meningitidis
1Servicio de Bacteriología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. jasaez@isciii.es
Abstract:
Meningococcal moderate resistance to penicillin (MICs 0.12 to 1 mg/l) was rarely reported before the 1980's in Spain. The frequency of isolation of resistant strains increased from 0.4% in 1985 to 42.6% in 1990. In the last few years, these strains have been reported in several countries, which suggests a change in the meningococcal response to penicillin. The resistance is due, at least in part, to a decreased affinity of penicillin binding protein 2 (PBP2) for penicillin. This decreased affinity has also been found in commensal Neisseriae. Population genetic studies demonstrate that recombinational events, replacing parts of the PBP2 gene by the corresponding regions of commensal species, followed by a rapid spread of the clones could be the origin of such resistant strains.
Insights
Meningococcal penicillin resistance has surged globally since the 1980s due to genetic changes in penicillin binding protein 2 (PBP2). This resistance likely stems from Neisseria recombination, impacting treatment strategies.
Area of Science:
- Microbiology
- Genetics
- Epidemiology
Background:
- Meningococcal resistance to penicillin was rare in Spain before the 1980s.
- A significant increase in resistant strains was observed between 1985 and 1990 in Spain.
- Recent reports indicate the emergence of resistant strains in multiple countries.
Purpose of the Study:
- To investigate the emergence and potential mechanisms of penicillin resistance in Neisseria meningitidis.
- To understand the genetic basis of altered penicillin susceptibility in meningococci.
Main Methods:
- Monitoring the frequency of penicillin-resistant Neisseria meningitidis isolates.
- Investigating the penicillin binding protein 2 (PBP2) in resistant strains.
- Conducting population genetic studies to identify genetic exchange events.
Main Results:
- Penicillin resistance in meningococci increased dramatically in Spain from 0.4% in 1985 to 42.6% in 1990.
- Reduced affinity of penicillin binding protein 2 (PBP2) for penicillin is a key factor in resistance.
- Similar PBP2 alterations were observed in commensal Neisseria species.
- Population genetic data suggests that recombination events involving the PBP2 gene, with sequences from commensal Neisseria, followed by clonal spread, are responsible for resistance.
Conclusions:
- The rise in meningococcal penicillin resistance is linked to genetic modifications in PBP2.
- Recombination with commensal Neisseria species appears to be the primary mechanism driving this resistance.
- The findings highlight the dynamic nature of antimicrobial resistance and the need for ongoing surveillance.