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Author Notes:

Address correspondence to Ashok K. Chopra, achopra@utmb.edu

We thank the Genomics Core (specifically, Tom Wood and Steven Widen), UTMB, for sequencing several of the aeromonad genomes.

Subjects:

Research Funding:

The financial support provided to A.K.C. through Leon Bromberg and Robert E. Shope and John S. Dunn Distinguished Chair in Global Health endowments, UTMB, is gratefully acknowledged.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Biotechnology & Applied Microbiology
  • Microbiology
  • BIOTECHNOLOGY & APPLIED MICROBIOLOGY
  • MICROBIOLOGY
  • SECRETION SYSTEM EFFECTOR
  • INTESTINAL EPITHELIAL-CELLS
  • N-ACYLHOMOSERINE LACTONES
  • SOFT-TISSUE INFECTIONS
  • AERUGINOSA EXOTOXIN-A
  • IN-VIVO VIRULENCE
  • PSEUDOMONAS-AERUGINOSA
  • BIOFILM FORMATION
  • CYTOTOXIC ENTEROTOXIN
  • CLINICAL ISOLATE

Functional Genomic Characterization of Virulence Factors from Necrotizing Fasciitis-Causing Strains of Aeromonas hydrophila

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Journal Title:

Applied and Environmental Microbiology

Volume:

Volume 80, Number 14

Publisher:

, Pages 4162-4183

Type of Work:

Article | Final Publisher PDF

Abstract:

The genomes of 10 Aeromonas isolates identified and designated Aeromonas hydrophila WI, Riv3, and NF1 to NF4; A. dhakensis SSU; A. jandaei Riv2; and A. caviae NM22 and NM33 were sequenced and annotated. Isolates NF1 to NF4 were from a patient with necrotizing fasciitis (NF). Two environmental isolates (Riv2 and -3) were from the river water from which the NF patient acquired the infection. While isolates NF2 to NF4 were clonal, NF1 was genetically distinct. Outside the conserved core genomes of these 10 isolates, several unique genomic features were identified. The most virulent strains possessed one of the following four virulence factors or a combination of them: cytotoxic enterotoxin, exotoxin A, and type 3 and 6 secretion system effectors AexU and Hcp. In a septicemic-mouse model, SSU, NF1, and Riv2 were the most virulent, while NF2 was moderately virulent. These data correlated with high motility and biofilm formation by the former three isolates. Conversely, in a mouse model of intramuscular infection, NF2 was much more virulent than NF1. Isolates NF2, SSU, and Riv2 disseminated in high numbers from the muscular tissue to the visceral organs of mice, while NF1 reached the liver and spleen in relatively lower numbers on the basis of colony counting and tracking of bioluminescent strains in real time by in vivo imaging. Histopathologically, degeneration of myofibers with significant infiltration of polymorphonuclear cells due to the highly virulent strains was noted. Functional genomic analysis provided data that allowed us to correlate the highly infectious nature of Aeromonas pathotypes belonging to several different species with virulence signatures and their potential ability to cause NF.

Copyright information:

© 2014, American Society for Microbiology.

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