Antimicrobial resistance of invasive pneumococci in Finland in 1999-2000
Marja Pihlajamäki1, Jari Jalava, Pentti Huovinen
1Antimicrobial Research Laboratory, National Public Health Institute, Turku, Finland. mapihla@utu.fi
Antimicrobial Agents and Chemotherapy
|May 23, 2003
Abstract:
The resistance patterns and macrolide resistance mechanisms of 910 Finnish invasive pneumococci isolated during 1999 and 2000 were studied. Macrolide resistance was detected in 6.9% of isolates. Penicillin resistance was detected in 1.5% of isolates, and penicillin intermediate resistance was detected in 4.0% of isolates. Active macrolide efflux, mediated by the mef(A) gene, was the most common macrolide resistance mechanism. Four macrolide-resistant isolates had mutations in rRNA or ribosomal protein L22.
Insights
Macrolide resistance in Finnish invasive pneumococci was 6.9%, primarily due to active efflux mediated by the mef(A) gene. A small percentage of resistant strains also showed mutations in rRNA or ribosomal protein L22.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Invasive pneumococcal disease remains a significant public health concern.
- Understanding antimicrobial resistance patterns, particularly to macrolides, is crucial for effective treatment.
- The prevalence and mechanisms of macrolide resistance in Streptococcus pneumoniae require ongoing surveillance.
Purpose of the Study:
- To investigate the resistance patterns of Finnish invasive pneumococci.
- To identify the macrolide resistance mechanisms employed by these isolates.
- To determine the prevalence of macrolide and penicillin resistance in the studied population.
Main Methods:
- Analysis of 910 invasive pneumococcal isolates collected in Finland during 1999-2000.
- Phenotypic detection of macrolide and penicillin resistance.
- Molecular identification of macrolide resistance mechanisms, including mef(A) gene detection and analysis of rRNA and ribosomal protein L22 mutations.
Main Results:
- Macrolide resistance was observed in 6.9% of the isolates.
- Penicillin resistance was detected in 1.5% and intermediate resistance in 4.0% of isolates.
- Active macrolide efflux via the mef(A) gene was the predominant resistance mechanism; four resistant isolates exhibited rRNA or ribosomal protein L22 mutations.
Conclusions:
- The mef(A) gene-mediated efflux is the primary mechanism of macrolide resistance in Finnish invasive pneumococci.
- A low but present level of macrolide resistance necessitates continued monitoring.
- Mutations in rRNA or ribosomal protein L22 represent alternative, less common, macrolide resistance pathways in these isolates.
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