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

Publication ,  Journal Article
Borkar, DS; Acharya, NR; Leong, C; Lalitha, P; Srinivasan, M; Oldenburg, CE; Cevallos, V; Lietman, TM; Evans, DJ; Fleiszig, SMJ
Published in: BMC Ophthalmol
April 24, 2014

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.

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Published In

BMC Ophthalmol

DOI

EISSN

1471-2415

Publication Date

April 24, 2014

Volume

14

Start / End Page

54

Location

England

Related Subject Headings

  • Visual Acuity
  • Pseudomonas aeruginosa
  • Prognosis
  • Ophthalmology & Optometry
  • Middle Aged
  • Microbial Sensitivity Tests
  • Male
  • Humans
  • Glucocorticoids
  • Genotype
 

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Borkar, D. S., Acharya, N. R., Leong, C., Lalitha, P., Srinivasan, M., Oldenburg, C. E., … Fleiszig, S. M. J. (2014). Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones. BMC Ophthalmol, 14, 54. https://doi.org/10.1186/1471-2415-14-54
Borkar, Durga S., Nisha R. Acharya, Chelsia Leong, Prajna Lalitha, Muthiah Srinivasan, Catherine E. Oldenburg, Vicky Cevallos, Thomas M. Lietman, David J. Evans, and Suzanne M. J. Fleiszig. “Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones.BMC Ophthalmol 14 (April 24, 2014): 54. https://doi.org/10.1186/1471-2415-14-54.
Borkar DS, Acharya NR, Leong C, Lalitha P, Srinivasan M, Oldenburg CE, et al. Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones. BMC Ophthalmol. 2014 Apr 24;14:54.
Borkar, Durga S., et al. “Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones.BMC Ophthalmol, vol. 14, Apr. 2014, p. 54. Pubmed, doi:10.1186/1471-2415-14-54.
Borkar DS, Acharya NR, Leong C, Lalitha P, Srinivasan M, Oldenburg CE, Cevallos V, Lietman TM, Evans DJ, Fleiszig SMJ. Cytotoxic clinical isolates of Pseudomonas aeruginosa identified during the Steroids for Corneal Ulcers Trial show elevated resistance to fluoroquinolones. BMC Ophthalmol. 2014 Apr 24;14:54.
Journal cover image

Published In

BMC Ophthalmol

DOI

EISSN

1471-2415

Publication Date

April 24, 2014

Volume

14

Start / End Page

54

Location

England

Related Subject Headings

  • Visual Acuity
  • Pseudomonas aeruginosa
  • Prognosis
  • Ophthalmology & Optometry
  • Middle Aged
  • Microbial Sensitivity Tests
  • Male
  • Humans
  • Glucocorticoids
  • Genotype