Virulence diversity among bacteremic Aeromonas isolates: ex vivo, animal, and clinical evidences.
BACKGROUND
The objective of this study was to compare virulence among different Aeromonas species causing bloodstream infections.


RESULTS
Nine of four species of Aeromonas blood isolates, including A. dhakensis, A. hydrophila, A. veronii and A. caviae were randomly selected for analysis. The species was identified by the DNA sequence matching of rpoD. Clinically, the patients with A. dhakensis bacteremia had a higher sepsis-related mortality rate than those with other species (37.5% vs. 0%, P = 0.028). Virulence of different Aeromonas species were tested in C. elegans, mouse fibroblast C2C12 cell line and BALB/c mice models. C. elegans fed with A. dhakensis and A. caviae had the lowest and highest survival rates compared with other species, respectively (all P values <0.0001). A. dhakensis isolates also exhibited more cytotoxicity in C2C12 cell line (all P values <0.0001). Fourteen-day survival rate of mice intramuscularly inoculated with A. dhakensis was lower than that of other species (all P values <0.0001). Hemolytic activity and several virulence factor genes were rarely detected in the A. caviae isolates.


CONCLUSIONS
Clinical data, ex vivo experiments, and animal studies suggest there is virulence variation among clinically important Aeromonas species.
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Graduate Institute of Clinical Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan.
Po-Lin
PL
Chen
Graduate Institute of Clinical Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan; National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Taipei, Taiwan.
Chi-Jung
CJ
Wu
Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University College of Medicine, Tainan, Taiwan; Research Center of Infectious Disease and Signaling, National Cheng Kung University, Tainan, Taiwan.
Pei-Jane
PJ
Tsai
Department of Medicine, Chi Mei Medical Center, Tainan, Taiwan; Department of Health and Nutrition, Chia Nan University of Pharmacy and Science, Tainan, Taiwan.
Hung-Jen
HJ
Tang
Department of Medicine, Chi Mei Medical Center, Tainan, Taiwan; Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan; Department of Clinical Pathology, Chi Mei Medical Center, Tainan, Taiwan.
Yin-Ching
YC
Chuang
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Nan-Yao
NY
Lee
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Ching-Chi
CC
Lee
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Chia-Wen
CW
Li
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Ming-Chi
MC
Li
Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan.
Chi-Chung
CC
Chen
Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan.
Hung-Wen
HW
Tsai
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Chun-Chun
CC
Ou
Department of Biochemistry and Molecular Biology, National Cheng Kung University College of Medicine, Tainan, Taiwan.
Chang-Shi
CS
Chen
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan; Department of Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan.
Wen-Chien
WC
Ko
D000333:Aeromonas / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D000818:Animals; D016470:Bacteremia; D017173:Caenorhabditis elegans; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D051379:Mice; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
D037521:Virulence Factors