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Published on: February 23, 2014
Resistance to β-lactams in Streptococcus pneumoniae
Martha von Specht1, Gabriela García Gabarrot2, Marta Mollerach3
1Grupo STREP de la Sociedad Argentina de Bacteriología, Micología y Parasitología Clínicas (SADEBAC), División de la Asociación Argentina de Microbiología, Argentina; Cátedra de Microbiología General, Departamento de Microbiología, Facultad de Ciencias Exactas Químicas y Naturales, Universidad Nacional de Misiones, Posadas, Misiones, Argentina.
Abstract:
Streptococcus pneumoniae is an important causal agent of pneumonia, meningitis, sepsis, bacteremia, and otitis media. Penicillin resistance rates in S. pneumoniae have remained stable in Argentina in the last years. In the late '90s more isolates with MIC of penicillin ≥2μg/ml were observed; however, their frequency has decreased in recent years. The phenotypic expression of penicillin resistance is due to a modification in penicillin-binding proteins associated with a mosaic structure in the coding genes. The expansion of successful resistant clones varies among the different regions and is influenced by the use of antibiotics, vaccines, particularly conjugated ones, as well as population density. Parenteral treatment with high doses of penicillin G continues to be effective for the treatment of pneumonia and bacteremia, oral aminopenicillins for otitis media and sinusitis and third generation cephalosporins for meningitis.
Insights
Penicillin resistance in Streptococcus pneumoniae remains stable in Argentina, with decreasing high-level resistance. Effective treatments include penicillin G for bacteremia and pneumonia, aminopenicillins for otitis, and cephalosporins for meningitis.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Streptococcus pneumoniae causes pneumonia, meningitis, sepsis, bacteremia, and otitis media.
- Penicillin resistance in S. pneumoniae has shown stable rates in Argentina recently.
- High-level penicillin resistance (MIC ≥2μg/ml) peaked in the late '90s but has since declined.
Purpose of the Study:
- To analyze trends in penicillin resistance of Streptococcus pneumoniae in Argentina.
- To understand the mechanisms and factors influencing the spread of resistant strains.
- To provide guidance on effective antibiotic treatments for S. pneumoniae infections.
Main Methods:
- Monitoring of penicillin resistance rates in S. pneumoniae isolates.
- Analysis of phenotypic resistance mechanisms involving penicillin-binding proteins and gene structures.
- Evaluation of factors such as antibiotic usage, vaccination, and population density.
Main Results:
- Penicillin resistance rates in S. pneumoniae have remained stable in Argentina.
- A decrease in the frequency of high-level penicillin resistance (MIC ≥2μg/ml) has been observed.
- Mechanisms of resistance involve modified penicillin-binding proteins and mosaic gene structures.
Conclusions:
- Parenteral penicillin G is effective for pneumonia and bacteremia.
- Oral aminopenicillins are suitable for otitis media and sinusitis.
- Third-generation cephalosporins remain a treatment option for meningitis.
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