Association of Aeromonas sobria with human infection

Abstract

Fifteen Aeromonas isolates from various human infections and nine isolates from polluted water were identified as either Aeromonas hydrophila or Aeromonas sobria and examined for cytotoxigenicity, enterotoxigenicity, adherence to epithelial cells, and other virulence-associated factors, including proteases, lipases, elastases, and hemolysins. Two groups cf organisms (I and II) were distinguishable based on differences in median lethal doses in mice and cytotoxicity for Y-1 adrenal cells. Group I clinical and environmental strains had median lethal doses of <107 colony-forming units, were cytotoxic, frequently possessed several virulence-associated factors, and had lysine decarboxylase-positive or Voges-Proskauer-positive phenotypes or both. Piliation of Aeromonas was associated strongly with ability to adhere to human buccal cells, and these characteristics were associated with group I strains. Group Il clinical and environmental strains had median lethal doses of '107 colony-forming units, were not cytotoxic, and usually were lysine decarboxylase negative or Voges-Proskauer negative or both. Clinical strains in group II exhibited enterotoxigenicity, which was not detected in group Il environmental strains. A. sobria was more frequently associated with human infections; 13 of the 15 clinical strains were A. sobria, and 2 were A. hydrophila. On the other hand, the majority of the environmental strains (seven of nine) were A. hydrophila.Aeromonas species are ubiquitous, waterborne microorganisms that have been implicated repeatedly as the causative agents of clinical illnesses, often serious, ranging from gastrointestinal and wound infections to septicemia (4,8,9,12,18,25,26). In compromised patients these illnesses may be fatal. Whereas a small proportion of humans, approximately 1%, are carriers of Aeromonas (26), infections frequently are acquired as a direct result of exposure to water harboring this microorganism (8,9,12,27).

Purification and Characterization of Enterotoxin Produced by Aeromonas sobria

“…Motile Aeromonas species, particularly A. hydrophila and A. sobria, are pathogens associated with acute gastroenteritis in both adults and children (2,7). Of these two pathogens, the virulence factors of A. hydrophila associated with diarrhea have been studied extensively.…”

Pili of Aeromonas hydrophila: Purification, Characterization, and Biological Role

“…The production of a cholera toxin-like enterotoxin by Aeromonas was reported on occasion (8,12,31,32), and recently, Rose et al reported purification and characterization of cholera toxin-like enterotoxin produced by Aeromonas hydrophila (27,28). On the other hand, HONMA AND N. NAKASONE there have been only a few reports on the colonization factors of Aeromonas thus far (6,10). Many kinds of pili as well as hemagglutinins of various pathogens have been shown to be responsible for the adhesion and to be colonization factors (11,17,26,30,33).…”

“…Although one of the hemagglutinins reported by Atkinson et al (A6-type hemagglutinin isolated from outer membrane proteins of Aeromonas) is probably important in adhesion to the intestinal epithelium (7), the role of other hemagglutinins and pili is still unclarified. The pili of Aeromonas have been studied by several investigators (6,10,29,35…”

Diversity of Aeromonas sp. in Flemish drinking water production plants as determined by gas‐liquid chromatographic analysis of cellular fatty acid methyl esters (FAMEs)

“…1992; Krovacek et a/. 1992a) as well as from clinical specimens (Daily et al 1981;Namdari and Bottone 1990;Joseph et al 1991;Kokka et al 1992). In fact, Aeromonas hydrophila and Aer.…”