Antimicrobial susceptibility, serotype and genotype distribution of meningococci in Portugal, 2001-2002
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1Antibiotic Resistance Unit, Centre of Bacteriology, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal.
Abstract:
One hundred and eighteen Neisseria meningitidis isolates were recovered from patients with invasive meningococcal disease in Portugal, over one year. Our study was undertaken to evaluate antimicrobial susceptibility, serogroup, serotype and genotype of isolates. One quarter (24.6%) of the isolates showed moderate resistance to penicillin and 47.4% were resistant to sulphadiazine. The two most common serosubtypes were C:2b:P1.5,2 (31.3%) and B:4:P1.15 (3.4%). Half (53.6%) of the isolates with moderate resistance to penicillin were phenotype C:2b:P1.5,2 (n=14), C:2b:P1.2 (n=1) or C:2b:NST (n=1); Pulsed-field gel electrophoresis (PFGE) showed that all these isolates were genetically related. Multilocus sequence typing (MLST) analysis of representative clones from each PFGE pattern showed the predominance of the ST-8 complex/cluster A4 among N. meningitidis with moderate resistance to penicillin. This clonal complex has been principally found in Southern Europe. The apparent emergence and dissemination of the hypervirulent ST-8 complex/cluster A4 among serogroup C strains increases the need for a continued surveillance of antimicrobial susceptibility of meningococci and of genotypic markers in Portugal.
Insights
Meningococcal disease surveillance in Portugal revealed moderate penicillin resistance in 24.6% of isolates, primarily linked to the ST-8 complex. This highlights the need for ongoing monitoring of antimicrobial resistance and genetic markers.
Area of Science:
- Microbiology
- Epidemiology
- Infectious Diseases
Background:
- Invasive meningococcal disease (IMD) remains a significant public health concern.
- Neisseria meningitidis is the causative agent of IMD.
- Antimicrobial resistance and genotypic characterization are crucial for effective disease management and prevention.
Purpose of the Study:
- To evaluate the antimicrobial susceptibility, serogroup, serotype, and genotype of Neisseria meningitidis isolates from invasive meningococcal disease cases in Portugal.
- To identify prevalent serosubtypes and genetic lineages associated with antimicrobial resistance.
- To assess the emergence and dissemination of specific clonal complexes.
Main Methods:
- Isolation and characterization of 118 Neisseria meningitidis strains from IMD patients.
- Antimicrobial susceptibility testing for penicillin and sulphadiazine.
- Serogrouping and serotyping.
- Pulsed-field gel electrophoresis (PFGE) for genetic relatedness assessment.
- Multilocus sequence typing (MLST) for genotypic analysis and clonal complex identification.
Main Results:
- 24.6% of isolates showed moderate resistance to penicillin; 47.4% were resistant to sulphadiazine.
- The most common serosubtypes were C:2b:P1.5,2 (31.3%) and B:4:P1.15 (3.4%).
- Penicillin-resistant isolates were predominantly associated with the ST-8 complex/cluster A4, a lineage prevalent in Southern Europe.
Conclusions:
- The study identified a concerning prevalence of moderate penicillin resistance in Neisseria meningitidis isolates in Portugal.
- The emergence and spread of the hypervirulent ST-8 complex/cluster A4 among serogroup C strains warrants attention.
- Continuous surveillance of antimicrobial susceptibility and genotypic markers is essential for controlling meningococcal disease in Portugal.
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