Upregulation of the PatAB Transporter Confers Fluoroquinolone Resistance to Streptococcus pseudopneumoniae
We characterized the mechanism of fluoroquinolone-resistance in two isolates of Streptococcus pseudopneumoniae having fluoroquinolone-efflux as unique mechanism of resistance. Whole genome sequencing and genetic transformation experiments were performed together with phenotypic determinations of the...
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| Language: | English |
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Frontiers Media S.A.
2017-10-01
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| Series: | Frontiers in Microbiology |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fmicb.2017.02074/full |
| _version_ | 1811325415107592192 |
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| author | María Alvarado Antonio J. Martín-Galiano María J. Ferrándiz Ángel Zaballos Adela G. de la Campa Adela G. de la Campa |
| author_facet | María Alvarado Antonio J. Martín-Galiano María J. Ferrándiz Ángel Zaballos Adela G. de la Campa Adela G. de la Campa |
| author_sort | María Alvarado |
| collection | DOAJ |
| description | We characterized the mechanism of fluoroquinolone-resistance in two isolates of Streptococcus pseudopneumoniae having fluoroquinolone-efflux as unique mechanism of resistance. Whole genome sequencing and genetic transformation experiments were performed together with phenotypic determinations of the efflux mechanism. The PatAB pump was identified as responsible for efflux of ciprofloxacin (MIC of 4 μg/ml), ethidium bromide (MICs of 8–16 μg/ml) and acriflavine (MICs of 4–8 μg/ml) in both isolates. These MICs were at least 8-fold lower in the presence of the efflux inhibitor reserpine. Complete genome sequencing indicated that the sequence located between the promoter of the patAB operon and the initiation codon of patA, which putatively forms an RNA stem-loop structure, may be responsible for the efflux phenotype. RT-qPCR determinations performed on RNAs of cultures treated or not treated with subinhibitory ciprofloxacin concentrations were performed. While no significant changes were observed in wild-type Streptococcus pneumoniae R6 strain, increases in transcription were detected in the ciprofloxacin-efflux transformants obtained with DNA from efflux-positive isolates, in the ranges of 1.4 to 3.4-fold (patA) and 2.1 to 2.9-fold (patB). Ciprofloxacin-induction was related with a lower predicted free energy for the stem-loop structure in the RNA of S. pseudopneumoniae isolates (−13.81 and −8.58) than for R6 (−15.32 kcal/mol), which may ease transcription. The presence of these regulatory variations in commensal S. pseudopneumoniae isolates, and the possibility of its transfer to Streptococcus pneumoniae by genetic transformation, could increase fluoroquinolone resistance in this important pathogen. |
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| institution | Directory Open Access Journal |
| issn | 1664-302X |
| language | English |
| last_indexed | 2024-04-13T14:32:34Z |
| publishDate | 2017-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Microbiology |
| spelling | doaj.art-3c0fc34a62914a349253f770f1b2ea5a2022-12-22T02:43:08ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2017-10-01810.3389/fmicb.2017.02074299885Upregulation of the PatAB Transporter Confers Fluoroquinolone Resistance to Streptococcus pseudopneumoniaeMaría Alvarado0Antonio J. Martín-Galiano1María J. Ferrándiz2Ángel Zaballos3Adela G. de la Campa4Adela G. de la Campa5Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, SpainUnidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, SpainUnidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, SpainUnidad de Genómica, Instituto de Salud Carlos III, Madrid, SpainUnidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, SpainPresidencia, Consejo Superior de Investigaciones Científicas, Madrid, SpainWe characterized the mechanism of fluoroquinolone-resistance in two isolates of Streptococcus pseudopneumoniae having fluoroquinolone-efflux as unique mechanism of resistance. Whole genome sequencing and genetic transformation experiments were performed together with phenotypic determinations of the efflux mechanism. The PatAB pump was identified as responsible for efflux of ciprofloxacin (MIC of 4 μg/ml), ethidium bromide (MICs of 8–16 μg/ml) and acriflavine (MICs of 4–8 μg/ml) in both isolates. These MICs were at least 8-fold lower in the presence of the efflux inhibitor reserpine. Complete genome sequencing indicated that the sequence located between the promoter of the patAB operon and the initiation codon of patA, which putatively forms an RNA stem-loop structure, may be responsible for the efflux phenotype. RT-qPCR determinations performed on RNAs of cultures treated or not treated with subinhibitory ciprofloxacin concentrations were performed. While no significant changes were observed in wild-type Streptococcus pneumoniae R6 strain, increases in transcription were detected in the ciprofloxacin-efflux transformants obtained with DNA from efflux-positive isolates, in the ranges of 1.4 to 3.4-fold (patA) and 2.1 to 2.9-fold (patB). Ciprofloxacin-induction was related with a lower predicted free energy for the stem-loop structure in the RNA of S. pseudopneumoniae isolates (−13.81 and −8.58) than for R6 (−15.32 kcal/mol), which may ease transcription. The presence of these regulatory variations in commensal S. pseudopneumoniae isolates, and the possibility of its transfer to Streptococcus pneumoniae by genetic transformation, could increase fluoroquinolone resistance in this important pathogen.http://journal.frontiersin.org/article/10.3389/fmicb.2017.02074/fullDNA topoisomerasesefflux pumpsfluoroquinolonestranscription regulationStreptococcus pseudopneumoniae |
| spellingShingle | María Alvarado Antonio J. Martín-Galiano María J. Ferrándiz Ángel Zaballos Adela G. de la Campa Adela G. de la Campa Upregulation of the PatAB Transporter Confers Fluoroquinolone Resistance to Streptococcus pseudopneumoniae Frontiers in Microbiology DNA topoisomerases efflux pumps fluoroquinolones transcription regulation Streptococcus pseudopneumoniae |
| title | Upregulation of the PatAB Transporter Confers Fluoroquinolone Resistance to Streptococcus pseudopneumoniae |
| title_full | Upregulation of the PatAB Transporter Confers Fluoroquinolone Resistance to Streptococcus pseudopneumoniae |
| title_fullStr | Upregulation of the PatAB Transporter Confers Fluoroquinolone Resistance to Streptococcus pseudopneumoniae |
| title_full_unstemmed | Upregulation of the PatAB Transporter Confers Fluoroquinolone Resistance to Streptococcus pseudopneumoniae |
| title_short | Upregulation of the PatAB Transporter Confers Fluoroquinolone Resistance to Streptococcus pseudopneumoniae |
| title_sort | upregulation of the patab transporter confers fluoroquinolone resistance to streptococcus pseudopneumoniae |
| topic | DNA topoisomerases efflux pumps fluoroquinolones transcription regulation Streptococcus pseudopneumoniae |
| url | http://journal.frontiersin.org/article/10.3389/fmicb.2017.02074/full |
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