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Characterization of recombinant fluoroquinolone-resistant pneumococcus-like isolates
Luz Balsalobre1, Montserrat Ortega, Adela G de la Campa
1Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III and CIBER de Enfermedades Respiratorias, Majadahonda. luzbal@isciii.es
Fluoroquinolone-resistant streptococci were identified as atypical pneumococci. Genetic analysis revealed mosaic DNA topoisomerase genes and a close relationship between these atypical pneumococci and Streptococcus pseudopneumoniae.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Fluoroquinolone resistance is a growing concern in streptococcal infections.
- Streptococcus pneumoniae (pneumococci) are significant human pathogens.
- Atypical pneumococci with recombinant DNA topoisomerase genes require further characterization.
Purpose of the Study:
- To characterize fluoroquinolone-resistant streptococcal isolates with recombinant DNA topoisomerase genes.
- To determine the phylogenetic relationships of these isolates.
- To investigate the genetic basis of their resistance and atypical phenotype.
Main Methods:
- Phenotypic and genotypic analyses were performed on fourteen resistant streptococcal isolates.
- Phylogenetic analysis utilized sequences of seven housekeeping alleles.
- Gene order of the atp operon and recombination evidence were assessed.
Main Results:
- Phenotypic tests classified the isolates as atypical pneumococci.
- Phylogenetic analysis placed isolates with Streptococcus pneumoniae, Streptococcus pseudopneumoniae, and Streptococcus mitis.
- Recombination within housekeeping alleles of the S. pseudopneumoniae population was evident.
Conclusions:
- Confirms the existence of pneumococci among alpha-hemolytic streptococci with mosaic DNA topoisomerase genes.
- Reveals a close evolutionary relationship between atypical pneumococci and S. pseudopneumoniae.
- Highlights the genetic complexity contributing to fluoroquinolone resistance in streptococci.
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