Giuseppe
Emeritus
[Source: Antimicrobial Agents and Chemotherapy, full text: (LINK). Abstract, edited.]
------
Characterization of recombinant fluoroquinolone-resistant pneumococcus-like isolates
Luz Balsalobre 1,*, Montserrat Ortegaand 1 and Adela G. de la Campa 1,2
Author Affiliations: <SUP>1</SUP>Unidad de Gen?tica Bacteriana, Centro Nacional de Microbiolog?a, Instituto de Salud Carlos III and CIBER de Enfermedades Respiratorias, Majadahonda; <SUP>2</SUP>Consejo Superior de Investigaciones Cient?ficas, Madrid, Spain
ABSTRACT
Fourteen fluoroquinolone-resistant streptococcal isolates with recombinant DNA topoisomerase genes, preliminary identified as pneumococci, were further characterized using phenotypic and genotypic approaches. Phenotypic tests classified them as atypical pneumococci. Phylogenetic relationships were analyzed by using the sequences of seven housekeeping alleles from these isolates and those of Streptococcus pneumoniae, Streptococcus mitis, Streptococcus oralis, and Streptococcus pseudopneumoniae isolates. Four isolates grouped with S. pneumoniae, seven with S. pseudoneumoniae, and three with S. mitis. These results generally agreed with those obtained with the optochin susceptibility test and with the organization of the atp operon chromosomal region, encoding the F<SUB>0</SUB>F<SUB>1</SUB> H<SUP>+</SUP>-ATPase (the target of optochin). All seven isolates grouping with S. pseudopneumoniae share the same spr1368-atpC-atpA gene order; all four grouping with S. pneumoniae share the spr1368-IS1239-atpC-atpA, and two out of the three grouping with S. mitis share the spr1284-atpC-atpA. In addition, evidences for recombination within the seven housekeeping alleles of the S. pseudoneumoniae population were provided by several methods: the index of association (0.4598, P< 0.001), the pairwise homoplasy index, and the split decomposition method. This study confirms the existence of pneumococci among the α-hemolytic streptococci with DNA topoisomerase genes showing a mosaic structure, and reveals a close relationship between atypical pneumococci and S. pseudopneumoniae.
FOOTNOTES
* Corresponding author. Mailing address: Unidad de Gen?tica Bacteriana, Centro Nacional de Microbiolog?a, Instituto de Salud Carlos III, Crta. de Majadahonda a Pozuelo s/n, 28220 Majadahonda, Madrid, Spain. Phone: (+34) 91 822 3902. Fax: (+34) 91 509 7919. E-mail: luzbal@isciii.es
Copyright ? 2012, American Society for Microbiology. All Rights Reserved.
-Author Affiliations: <SUP>1</SUP>Unidad de Gen?tica Bacteriana, Centro Nacional de Microbiolog?a, Instituto de Salud Carlos III and CIBER de Enfermedades Respiratorias, Majadahonda; <SUP>2</SUP>Consejo Superior de Investigaciones Cient?ficas, Madrid, Spain
ABSTRACT
Fourteen fluoroquinolone-resistant streptococcal isolates with recombinant DNA topoisomerase genes, preliminary identified as pneumococci, were further characterized using phenotypic and genotypic approaches. Phenotypic tests classified them as atypical pneumococci. Phylogenetic relationships were analyzed by using the sequences of seven housekeeping alleles from these isolates and those of Streptococcus pneumoniae, Streptococcus mitis, Streptococcus oralis, and Streptococcus pseudopneumoniae isolates. Four isolates grouped with S. pneumoniae, seven with S. pseudoneumoniae, and three with S. mitis. These results generally agreed with those obtained with the optochin susceptibility test and with the organization of the atp operon chromosomal region, encoding the F<SUB>0</SUB>F<SUB>1</SUB> H<SUP>+</SUP>-ATPase (the target of optochin). All seven isolates grouping with S. pseudopneumoniae share the same spr1368-atpC-atpA gene order; all four grouping with S. pneumoniae share the spr1368-IS1239-atpC-atpA, and two out of the three grouping with S. mitis share the spr1284-atpC-atpA. In addition, evidences for recombination within the seven housekeeping alleles of the S. pseudoneumoniae population were provided by several methods: the index of association (0.4598, P< 0.001), the pairwise homoplasy index, and the split decomposition method. This study confirms the existence of pneumococci among the α-hemolytic streptococci with DNA topoisomerase genes showing a mosaic structure, and reveals a close relationship between atypical pneumococci and S. pseudopneumoniae.
FOOTNOTES
* Corresponding author. Mailing address: Unidad de Gen?tica Bacteriana, Centro Nacional de Microbiolog?a, Instituto de Salud Carlos III, Crta. de Majadahonda a Pozuelo s/n, 28220 Majadahonda, Madrid, Spain. Phone: (+34) 91 822 3902. Fax: (+34) 91 509 7919. E-mail: luzbal@isciii.es
Copyright ? 2012, American Society for Microbiology. All Rights Reserved.
------