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What about antibiotic resistance in Neisseria lactamica?
L Arreaza1, C Salcedo, B Alcalá
1Servicio de Bacteriología, Laboratorio de Referencia de Meningococos, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
Abstract:
The in vitro activity of penicillin, ampicillin, cefotaxime, ceftriaxone, rifampicin and ciprofloxacin against 286 Neisseria lactamica isolates was determined by agar dilution and the category of susceptibility was analysed in accordance with the criteria used for Neisseria meningitidis. All isolates were considered to have intermediate susceptibility to penicillin. A total of 1.7% of the isolates were resistant to ampicillin but all were susceptible to cefotaxime and ceftriaxone. Rifampicin MICs ranged between 0.12 and 2 mg/L. Six isolates (2.1%) showed decreased susceptibility to ciprofloxacin.
Insights
This study assessed antibiotic susceptibility in Neisseria lactamica. Most isolates were susceptible to common antibiotics, but some showed resistance to ampicillin and decreased susceptibility to ciprofloxacin.
Area of Science:
- Microbiology
- Antimicrobial Resistance
- Bacterial Pathogenesis
Background:
- Neisseria lactamica is a commensal bacterium.
- Understanding its antibiotic susceptibility is crucial for differentiating it from pathogenic Neisseria meningitidis.
- Emerging resistance patterns in commensal bacteria can provide early warnings of resistance in related pathogens.
Purpose of the Study:
- To determine the in vitro antibiotic susceptibility profile of Neisseria lactamica isolates.
- To compare susceptibility patterns with established criteria for Neisseria meningitidis.
Main Methods:
- Agar dilution method was used to test the activity of six antibiotics: penicillin, ampicillin, cefotaxime, ceftriaxone, rifampicin, and ciprofloxacin.
- Susceptibility categories were analyzed based on Neisseria meningitidis criteria.
- Minimum Inhibitory Concentrations (MICs) were determined for rifampicin.
Main Results:
- All 286 Neisseria lactamica isolates showed intermediate susceptibility to penicillin.
- 1.7% of isolates were resistant to ampicillin.
- All isolates remained susceptible to cefotaxime and ceftriaxone.
- Rifampicin MICs ranged from 0.12 to 2 mg/L.
- 2.1% of isolates exhibited decreased susceptibility to ciprofloxacin.
Conclusions:
- Neisseria lactamica generally remains susceptible to third-generation cephalosporins like cefotaxime and ceftriaxone.
- The emergence of ampicillin resistance and reduced ciprofloxacin susceptibility warrants ongoing surveillance.
- Standardized susceptibility testing criteria for Neisseria meningitidis are applicable to Neisseria lactamica.