Clinical significance and distribution of putative virulence markers of 116 consecutive clinical Aeromonas isolates in southern Taiwan.
OBJECTIVE
The objectives of this study were to elucidate the clinical manifestations of Aeromonas infections and the association of putative virulence genes with clinical invasiveness.


METHODS
116 consecutive clinical Aeromonas isolates collected from July 1999 to June 2001 in a medical center in southern Taiwan were included. All isolates were identified by biochemical phenotyping and their genomic sequences encoding eight putative virulence factors, including cytolytic enterotoxin (AHCYTOEN), aerolysin (aerA), hemolysin (hlyA), heat-labile enterotoxin (alt), heat-stable enterotoxin (ast), and components of type III secretion system (ascV, aexT and ascF-ascG) were analyzed using polymerase chain reaction and colony blot hybridization. The association of clinical diseases of the patients with the putative virulence genes in the isolates was analyzed.


RESULTS
Sixty-two percent of Aeromonas isolates caused clinically evident infections, of which the major clinical manifestations were primary bacteremia (40%), followed by soft tissue infections (27%), and hepatobiliary tract infections (15%). Liver cirrhosis (36%), malignancy (25%), and hepatobiliary diseases (13%) were the major underlying diseases in patients with Aeromonas bacteremia. The majority (64%) of patients with Aeromonas hepatobiliary infections had underlying hepatobiliary diseases, whereas 71% of those with soft tissue infections had antecedent water- or soil-related injuries. The crude fatality rate for Aeromonas infections was 26%. Aeromonas hydrophila complex was the most common (52%) of the three major complex groups investigated, followed by Aeromonas sobria complex (24%) and Aeromonas caviae complex (23%). None of the eight putative virulence factors was associated with invasiveness or bacteremia.


CONCLUSIONS
Primary bacteremia, soft tissue infections, and hepatobiliary tract infections are the three major clinical manifestations of invasive Aeromonas infections in southern Taiwan. This study found no association between the presence of AHCYTOEN, aerA, hlyA, alt, ast, ascV, aexT or ascF-ascG genes in Aeromonas isolates and the development of extra-intestinal infections or bacteremia.
Wu
Chi-Jung
CJ
Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Wu
Jiunn-Jong
JJ
Yan
Jing-Jou
JJ
Lee
Hsin-Chun
HC
Lee
Nan-Yao
NY
Chang
Chia-Ming
CM
Shih
Hsin-I
HI
Wu
Hsiu-Mei
HM
Wang
Li-Rong
LR
Ko
Wen-Chien
WC
D000333:Aeromonas / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D016470:Bacteremia / Q000382:microbiology / Q000503:physiopathology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001660:Biliary Tract Diseases / Q000382:microbiology / Q000503:physiopathology; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology / Q000503:physiopathology*; D006785:Hospitals, University; D006801:Humans; D008107:Liver Diseases / Q000382:microbiology / Q000503:physiopathology; D018461:Soft Tissue Infections / Q000382:microbiology / Q000503:physiopathology; D013624:Taiwan / Q000453:epidemiology; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D037521:Virulence Factors