Viridans Group Streptococci Are Donors in Horizontal Transfer of Topoisomerase IV Genes to
            <i>Streptococcus pneumoniae</i>

Balsalobre, Luz; Ferrándiz, Marı́a José; Liñares, Josefina; Tubau, Fé; Campa, Adela G. de la

doi:10.1128/aac.47.7.2072-2081.2003

Cited by 100 publications

(90 citation statements)

References 54 publications

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“…Four isolates possessed a large number of amino acid substitutions (5 to 10) within the QRDRs. The nature of these changes is evidence of transfer of genetic material from viridans group streptococci to pneumococci, as described previously (2). It would appear that this does not have any effect on fluoroquinolone susceptibility.…”

Section: Discussionmentioning

confidence: 58%

Prevalence and Molecular Analysis of Macrolide and Fluoroquinolone Resistance among Isolates of Streptococcus pneumoniae Collected during the 2000-2001 PROTEKT US Study

2004

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The PROTEKT US (Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin in the United States) surveillance program was established to determine the prevalence and mechanisms of antibacterial resistance among bacterial pathogens from patients with community-acquired respiratory tract infections. In year 1 of the PROTEKT US study, 10,103 isolates of Streptococcus pneumoniae, including 3,133 erythromycin-resistant strains and 81 levofloxacin-resistant strains, were collected from 206 centers. We report on the molecular analyses of these resistant strains. The resistance genotypes among the 3,044 typed macrolide-resistant isolates overall were mef(A) (n ‫؍‬ 2,157; 70.9%), erm(B) (n ‫؍‬ 530; 17.4%), mef(A) erm(B) (n ‫؍‬ 304; 10.0%), and erm(A) subclass erm(TR) (n ‫؍‬ 5; 0.2%). Fifty (1.6%) macrolide-resistant isolates were negative for the mef and the erm resistance genes. Seventy-eight (96.3%) of the 81 levofloxacin-resistant isolates analyzed possessed multiple mutations in the gyrA, gyrB, parC, and/or parE quinolone resistance-determining regions. A total of 43 known multilocus sequence typing (MLST) profiles (or single-or double-locus variants) accounted for 75 of 81 isolates. There was no evidence of dissemination of fluoroquinolone-resistant clones within the United States; however, 12 isolates with the same MLST profile were located in one center in Massachusetts. Almost 90% of the erythromycin-resistant isolates and approximately one-third of the levofloxacin-resistant isolates were multidrug resistant.

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Section: Discussionmentioning

confidence: 58%

Prevalence and Molecular Analysis of Macrolide and Fluoroquinolone Resistance among Isolates of Streptococcus pneumoniae Collected during the 2000-2001 PROTEKT US Study

2004

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“…Table 3 shows that members of the TetR family were detected in 144 microbial genomes belonging to 80 genera and 113 species of gram-positive and ␣-, ␤-, and ␥-proteobacteria, cyanobacteria, and archaea, indicating wide taxonomic distribution. We have found that proteins of the TetR family are encoded both in chromosomes and in plasmids, and the mobility of the latter elements could be a source of the spread of genes in this family via horizontal transfer (147, 383), as is also the case with catabolic genes (77,160,236,410,426), antimicrobial resistance determinants (20,100,124), and 16S rRNA genes (347).…”

Section: Identification Of Tetr Family Members In Dna and Protein Datmentioning

confidence: 99%

The TetR Family of Transcriptional Repressors

Ramos

Martínez-Bueno

Molina‐Henares

et al. 2005

Microbiol Mol Biol Rev

988

1,133

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We have developed a general profile for the proteins of the TetR family of repressors. The stretch that best defines the profile of this family is made up of 47 amino acid residues that correspond to the helix-turn-helix DNA binding motif and adjacent regions in the three-dimensional structures of TetR, QacR, CprB, and EthR, four family members for which the function and three-dimensional structure are known. We have detected a set of 2,353 nonredundant proteins belonging to this family by screening genome and protein databases with the TetR profile. Proteins of the TetR family have been found in 115 genera of gram-positive, α-, β-, and γ-proteobacteria, cyanobacteria, and archaea. The set of genes they regulate is known for 85 out of the 2,353 members of the family. These proteins are involved in the transcriptional control of multidrug efflux pumps, pathways for the biosynthesis of antibiotics, response to osmotic stress and toxic chemicals, control of catabolic pathways, differentiation processes, and pathogenicity. The regulatory network in which the family member is involved can be simple, as in TetR (i.e., TetR bound to the target operator represses tetA transcription and is released in the presence of tetracycline), or more complex, involving a series of regulatory cascades in which either the expression of the TetR family member is modulated by another regulator or the TetR family member triggers a cell response to react to environmental insults. Based on what has been learned from the cocrystals of TetR and QacR with their target operators and from their three-dimensional structures in the absence and in the presence of ligands, and based on multialignment analyses of the conserved stretch of 47 amino acids in the 2,353 TetR family members, two groups of residues have been identified. One group includes highly conserved positions involved in the proper orientation of the helix-turn-helix motif and hence seems to play a structural role. The other set of less conserved residues are involved in establishing contacts with the phosphate backbone and target bases in the operator. Information related to the TetR family of regulators has been updated in a database that can be accessed at www.bactregulators.org

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“…1 and unpublished observations). Quite surprisingly, however, they also hybridized with the ant probe, a gene that is not normally present in S. pneumoniae but that is found in S. mitis and S. oralis (4).…”

Section: Phenotypic Characteristics Of Optmentioning

confidence: 99%

Molecular Characterization of Disease-Associated Streptococci of the Mitis Group That Are Optochin Susceptible

Balsalobre¹,

Hernández-Madrid²,

Llull

et al. 2006

J Clin Microbiol

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Eight optochin-susceptible (Opt s ) alpha-hemolytic (viridans) streptococcus isolates were characterized at the molecular level. These isolates showed phenotypic characteristics typical of both viridans streptococci and Streptococcus pneumoniae. Comparison of the sequence of housekeeping genes from these isolates with those of S. pneumoniae, Streptococcus mitis, Streptococcus oralis, and Streptococcus pseudopneumoniae suggested that the Opt s isolates corresponded to streptococci of the mitis group. Besides, the Opt s streptococci were negative by a Gen-Probe AccuProbe pneumococcus test and hybridized with specific pneumococcal probes (lytA and ply) but also with ant, a gene not present in most S. pneumoniae strains. Moreover, the isolates were insoluble in 1% sodium deoxycholate but completely dissolved in 0.1% deoxycholate. Sequence analysis of the lytA gene revealed that the Opt s streptococci carried lytA alleles characteristic of those present in nonpneumococcal streptococci of the mitis group. The determination of the partial nucleotide sequence embracing the atp operon encoding the F o F 1 H ؉ -ATPase indicated that the optochin susceptibility of the isolates was due to the acquisition of atpC, atpA, and part of atpB from S. pneumoniae by horizontal gene transfer.

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Viridans Group Streptococci Are Donors in Horizontal Transfer of Topoisomerase IV Genes to Streptococcus pneumoniae

Cited by 100 publications

References 54 publications

Prevalence and Molecular Analysis of Macrolide and Fluoroquinolone Resistance among Isolates of Streptococcus pneumoniae Collected during the 2000-2001 PROTEKT US Study

Prevalence and Molecular Analysis of Macrolide and Fluoroquinolone Resistance among Isolates of Streptococcus pneumoniae Collected during the 2000-2001 PROTEKT US Study

The TetR Family of Transcriptional Repressors

Molecular Characterization of Disease-Associated Streptococci of the Mitis Group That Are Optochin Susceptible

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