Neisseria meningitidis Antimicrobial Resistance in Italy, 2006 to 2016

Area of Science:

• Microbiology
• Infectious Diseases
• Epidemiology

Background:

• Neisseria meningitidis is a significant cause of bacterial meningitis and sepsis.
• Monitoring antimicrobial resistance is crucial for effective treatment and public health strategies.
• Invasive meningococcal disease (IMD) surveillance provides critical data on pathogen trends.

Purpose of the Study:

• To assess the antimicrobial susceptibility patterns of invasive Neisseria meningitidis strains in Italy over an 11-year period.
• To identify emerging resistance trends and characterize resistant isolates.
• To inform clinical management and public health interventions against meningococcal disease.

Main Methods:

• Retrospective analysis of 866 invasive Neisseria meningitidis isolates collected over 11 years.
• Antimicrobial susceptibility testing was performed using standard microbiological methods.
• Serogrouping and molecular typing (e.g., clonal complex analysis) were conducted.

Main Results:

• Overall, 866 Neisseria meningitidis strains were analyzed for antimicrobial susceptibility.
• Low-level resistance was detected for ciprofloxacin (2 strains) and rifampin (6 strains).
• Penicillin intermediate resistance was found in 45% of strains, notably associated with hypervirulent serogroup C clonal complex 11.
• All tested strains demonstrated susceptibility to cephalosporins.

Conclusions:

• Neisseria meningitidis in Italy remains highly susceptible to cephalosporins, a key antibiotic class for treatment.
• Emerging resistance to ciprofloxacin and rifampin requires continued monitoring.
• The prevalence of penicillin intermediate strains, particularly within serogroup C CC11, highlights the need for ongoing surveillance and potential treatment guideline adjustments.