Cargando…

Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones

BACKGROUND: To determine the relationship between type three secretion genotype and fluoroquinolone resistance for P. aeruginosa strains isolated from microbial keratitis during the Steroids for Corneal Ulcers Trial (SCUT) and for two laboratory strains, PA103 and PAO1. METHODS: Confirmed P. aerugin...

Descripción completa

Detalles Bibliográficos
Autores principales: Borkar, Durga S, Acharya, Nisha R, Leong, Chelsia, Lalitha, Prajna, Srinivasan, Muthiah, Oldenburg, Catherine E, Cevallos, Vicky, Lietman, Thomas M, Evans, David J, Fleiszig, Suzanne M J
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008435/
https://www.ncbi.nlm.nih.gov/pubmed/24761794
http://dx.doi.org/10.1186/1471-2415-14-54
_version_ 1782314449046077440
author Borkar, Durga S
Acharya, Nisha R
Leong, Chelsia
Lalitha, Prajna
Srinivasan, Muthiah
Oldenburg, Catherine E
Cevallos, Vicky
Lietman, Thomas M
Evans, David J
Fleiszig, Suzanne M J
author_facet Borkar, Durga S
Acharya, Nisha R
Leong, Chelsia
Lalitha, Prajna
Srinivasan, Muthiah
Oldenburg, Catherine E
Cevallos, Vicky
Lietman, Thomas M
Evans, David J
Fleiszig, Suzanne M J
author_sort Borkar, Durga S
collection PubMed
description BACKGROUND: To determine the relationship between type three secretion genotype and fluoroquinolone resistance for P. aeruginosa strains isolated from microbial keratitis during the Steroids for Corneal Ulcers Trial (SCUT) and for two laboratory strains, PA103 and PAO1. METHODS: Confirmed P. aeruginosa isolates from the SCUT were divided into exoU(+) or exoU(−). The exoU(+) strains contained the gene encoding ExoU, a powerful phospholipase toxin delivered into host cells by the type three secretion system. Isolates were then assessed for susceptibility to fluoroquinolone, cephalosporin, and aminoglycoside antibiotics using disk diffusion assays. Etest was used to determine the MIC of moxifloxacin and other fluoroquinolones. Laboratory isolates in which the exoU gene was added or deleted were also tested. RESULTS: A significantly higher proportion of exoU(+) strains were resistant to ciprofloxacin (p = 0.001), gatifloxacin (p = 0.003), and ofloxacin (p = 0.002) compared to exoU(−) isolates. There was no significant difference between exoU(+) or exoU(−) negative isolates with respect to susceptibility to other antibiotics except gentamicin. Infections involving resistant exoU(+) strains trended towards worse clinical outcome. Deletion or acquisition of exoU in laboratory isolates did not affect fluoroquinolone susceptibility. CONCLUSIONS: Fluoroquinolone susceptibility of P. aeruginosa isolated from the SCUT is consistent with previous studies showing elevated resistance involving exoU encoding (cytotoxic) strains, and suggest worse clinical outcome from infections involving resistant isolates. Determination of exoU expression in clinical isolates of P. aeruginosa may be helpful in directing clinical management of patients with microbial keratitis.
format Online
Article
Text
id pubmed-4008435
institution National Center for Biotechnology Information
language English
publishDate 2014
publisher BioMed Central
record_format MEDLINE/PubMed
spelling pubmed-40084352014-05-03 Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones Borkar, Durga S Acharya, Nisha R Leong, Chelsia Lalitha, Prajna Srinivasan, Muthiah Oldenburg, Catherine E Cevallos, Vicky Lietman, Thomas M Evans, David J Fleiszig, Suzanne M J BMC Ophthalmol Research Article BACKGROUND: To determine the relationship between type three secretion genotype and fluoroquinolone resistance for P. aeruginosa strains isolated from microbial keratitis during the Steroids for Corneal Ulcers Trial (SCUT) and for two laboratory strains, PA103 and PAO1. METHODS: Confirmed P. aeruginosa isolates from the SCUT were divided into exoU(+) or exoU(−). The exoU(+) strains contained the gene encoding ExoU, a powerful phospholipase toxin delivered into host cells by the type three secretion system. Isolates were then assessed for susceptibility to fluoroquinolone, cephalosporin, and aminoglycoside antibiotics using disk diffusion assays. Etest was used to determine the MIC of moxifloxacin and other fluoroquinolones. Laboratory isolates in which the exoU gene was added or deleted were also tested. RESULTS: A significantly higher proportion of exoU(+) strains were resistant to ciprofloxacin (p = 0.001), gatifloxacin (p = 0.003), and ofloxacin (p = 0.002) compared to exoU(−) isolates. There was no significant difference between exoU(+) or exoU(−) negative isolates with respect to susceptibility to other antibiotics except gentamicin. Infections involving resistant exoU(+) strains trended towards worse clinical outcome. Deletion or acquisition of exoU in laboratory isolates did not affect fluoroquinolone susceptibility. CONCLUSIONS: Fluoroquinolone susceptibility of P. aeruginosa isolated from the SCUT is consistent with previous studies showing elevated resistance involving exoU encoding (cytotoxic) strains, and suggest worse clinical outcome from infections involving resistant isolates. Determination of exoU expression in clinical isolates of P. aeruginosa may be helpful in directing clinical management of patients with microbial keratitis. BioMed Central 2014-04-24 /pmc/articles/PMC4008435/ /pubmed/24761794 http://dx.doi.org/10.1186/1471-2415-14-54 Text en Copyright © 2014 Borkar et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Borkar, Durga S
Acharya, Nisha R
Leong, Chelsia
Lalitha, Prajna
Srinivasan, Muthiah
Oldenburg, Catherine E
Cevallos, Vicky
Lietman, Thomas M
Evans, David J
Fleiszig, Suzanne M J
Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones
title Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones
title_full Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones
title_fullStr Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones
title_full_unstemmed Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones
title_short Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones
title_sort cytotoxic clinical isolates of pseudomonas aeruginosa identified during the steroids for corneal ulcers trial show elevated resistance to fluoroquinolones
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4008435/
https://www.ncbi.nlm.nih.gov/pubmed/24761794
http://dx.doi.org/10.1186/1471-2415-14-54
work_keys_str_mv AT borkardurgas cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT acharyanishar cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT leongchelsia cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT lalithaprajna cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT srinivasanmuthiah cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT oldenburgcatherinee cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT cevallosvicky cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT lietmanthomasm cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT evansdavidj cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones
AT fleiszigsuzannemj cytotoxicclinicalisolatesofpseudomonasaeruginosaidentifiedduringthesteroidsforcornealulcerstrialshowelevatedresistancetofluoroquinolones