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Antimicrobial susceptibility of Streptococcus pneumoniae isolated from pediatric carriers in Spain
J García-de-Lomas1, C Gimeno, E Millás
1Department of Microbiology, School of Medicine, University Hospital, Valencia, Spain.
Abstract:
The in vitro activity of several beta-lactam agents, macrolides, and cotrimoxazole was investigated against 53 Streptococcus pneumoniae isolates recovered from healthy children. The rates of resistance to penicillin or amoxicillin, cefaclor, and cefuroxime were 30%, 51%, and 37%, respectively. No cefotaxime-resistant isolates were found. Rates of resistance to erythromycin, clarithromycin, and cotrimoxazole were 22.6%, 13.2%, and 83%, respectively. Pneumococci with divergent antimicrobial susceptibility profiles (susceptible or moderately resistant vs. resistant isolates) coexisted in 32% samples, with divergencies more often involving beta-lactam agents and/or macrolides. In five of these samples, isolates belonged to different serotypes.
Insights
High resistance rates to common antibiotics like penicillin and cotrimoxazole were found in Streptococcus pneumoniae from children. Some samples showed mixed resistance levels, indicating complex antibiotic susceptibility patterns.
Area of Science:
- Microbiology
- Pediatric Infectious Diseases
- Antimicrobial Resistance
Background:
- Streptococcus pneumoniae is a leading cause of childhood bacterial infections.
- Understanding antimicrobial resistance patterns in pediatric isolates is crucial for effective treatment.
- Previous studies indicate emerging resistance, necessitating ongoing surveillance.
Purpose of the Study:
- To determine the in vitro antimicrobial activity of key antibiotic classes against Streptococcus pneumoniae isolates from healthy children.
- To assess the prevalence of resistance to beta-lactams, macrolides, and cotrimoxazole.
- To investigate the coexistence of divergent antimicrobial susceptibility profiles within samples.
Main Methods:
- In vitro susceptibility testing of 53 Streptococcus pneumoniae isolates.
- Evaluation of beta-lactam agents (penicillin, amoxicillin, cefaclor, cefuroxime, cefotaxime), macrolides (erythromycin, clarithromycin), and cotrimoxazole.
- Analysis of resistance rates and identification of mixed susceptibility profiles in samples.
Main Results:
- High resistance rates observed: penicillin/amoxicillin (30%), cefaclor (51%), cefuroxime (37%), erythromycin (22.6%), clarithromycin (13.2%), and cotrimoxazole (83%).
- No cefotaxime resistance detected.
- Divergent antimicrobial susceptibility profiles (mixed resistance) found in 32% of samples, frequently involving beta-lactams and macrolides.
- Different serotypes coexisted in 5 samples with divergent profiles.
Conclusions:
- Significant in vitro resistance to several commonly used antibiotics in pediatric Streptococcus pneumoniae isolates.
- High cotrimoxazole resistance is a major concern.
- The presence of mixed resistance profiles highlights the complexity of pneumococcal populations and potential challenges in empirical therapy.