title: Horizontal transfer of parC and gyrA in fluoroquinolone-resistant clinical isolates of Streptococcus pneumoniae.
abstract: We have analyzed genetically three clinical isolates (3180, 3870, and 1244) of Streptococcus pneumoniae with high-level ciprofloxacin resistance. Isolates 3180 and 3870 were atypical because of their insolubility in deoxycholate. However, they hybridized specifically with pneumococcal autolysin and pneumolysin gene probes and have typical pneumococcal atpC and atpA gene sequences. Analysis of the complete sequences of the parC and gyrA genes revealed total variations of 8 and 8.7% (isolate 3180) and 7.4 and 3.6% (isolate 3870), respectively, compared to the wild-type strain R6 sequence. The variations observed between the sequences of R6 and isolate 1244 were less than 0.9%. The structure of the gyrA and parC genes from isolates 3180 and 3870 was organized in sequence blocks that show different levels of divergence, suggesting a pattern of recombination. These results are evidence for recombination at the fluoroquinolone target genes in clinical isolates of S. pneumoniae. The genetically related viridans group streptococci could act as a reservoir for fluoroquinolone resistance genes.
authors.affiliation: Unidad de Genética Bacteriana (Consejo Superior de Investigaciones Científicas), Centro Nacional de Biología Fundamental, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Ferrándiz
authors.forename: A
authors.initials: A
authors.lastname: Fenoll
authors.forename: J
authors.initials: J
authors.lastname: Liñares
authors.forename: A G
authors.initials: AG
authors.lastname: De La Campa
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001483:Base Sequence; D015139:Blotting, Southern; D027081:DNA Gyrase; D015342:DNA Probes; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004352:Drug Resistance, Microbial; D024841:Fluoroquinolones; D022761:Gene Transfer, Horizontal; D006801:Humans; D008969:Molecular Sequence Data; D011008:Pneumococcal Infections / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics*
chemical_list: D000890:Anti-Infective Agents; D015342:DNA Probes; D024841:Fluoroquinolones; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II