Cytotoxic and haemagglutinating activities of motile Aeromonas species

Abstract

Summary. Cytotoxic and haemagglutinating properties were determined in 1 14 Aeromonas strains isolated from various sites in slaughtered lambs and from processed lamb meat. Cytotoxic activity on Vero cells was observed in 48 (42 YO) of the strains. It was more common in A . sobria and A . hydrophila isolates than with A . caviae isolates. Haemagglutination (HA) activity was found frequently in motile aeromonads irrespective of species; it was present in 50 YO of A . sobria strains, 51 YO of A. hydrophila strains and 48 YO of A. caviae strains. HA was inhibited by fucose, galactose and mannose at low concentration and, in most cases, two or three of these sugars were inhibitory. A significant association was found between certain HA-inhibition patterns and the production of cytotoxin by Aeromonas spp.

Prevalence, species differentiation, haemolytic activity, and antibiotic susceptibility of aeromonads in untreated well water

“…Three of these, namely hydrophila, caviae and sobria, are most commonly associated with disease in humans. A number of virulence factors have been associated with these organisms and may be responsible for their enteropathogenicity, these include the production of cytotoxins, enterotoxins and haemolysins (Gracey et al 1982, Singh & Sanyal 1992, Majeed & Macrae 1994. Burke et al (1983b) have shown that haemolytic aeromonads are also enterotoxigenic and suggested that the detection of the haemolytic activity is sufficient to discriminate enterotoxigenic Aeromonas species.…”

Production of an enterotoxin by a gastro-enteritis-associated Aeromonas strain

“…It is also used frequently for the detection of aeromonas enterotoxin [22][23][24][25]37]. The SMT allows for enterotoxin detection on a larger scale than is possible with the rabbit ileal loop test [30,37,38].…”

“…This has resulted in a great deal of controversy and confusion. However, such extracellular biologically active factors as enterotoxins, cytotoxins, haemolysins and proteases have been reported to be produced by motile aeromonads [21][22][23][24][25]. These properties are found more frequently, or better expressed, in strains isolated from diarrhoeal individuals than in those isolated from healthy control individuals or from the environment [26].…”

Virulence properties of motile aeromonads isolated from farmed frogs Rana tigerina and R. rugulosa

“…In the past Vero cells have been recommended as the cell line most appropriate for screening Aeronlonas cytotoxins (Kuijper et al 1989, Noterdaeme et al 1991. Many studies have used Vero cells alone to screen for cytotoxins (Vadivelu et al 1991, Majeed & MacRae 1994. While this assay may be appropriate for studies on human isolates, caution should be exercised when interpreting results for isolates of aquatic origin.…”

“…produce a range of extracellular toxins and enzymes and studies have attempted to correlate the production of potential virulence determinants with the pathogenicity and source of Aeromonas isolates (Hsu et al 1981, Santos et al 1988, Kirov et al 1994, Majeed & MacRae 1994, Pin et al 1994, Esteve et al 1995, Vadivelu et al 1995. Production of protease and haemolysin in particular have been implicated as key extracellular activities associated with pathogenicity of infections in both animals and humans (Cahill 1990, Janda 1991, Janda et al 1994.…”