Z. Rahim et Kms. Aziz, ENTEROTOXIGENICITY, HEMOLYTIC-ACTIVITY AND ANTIBIOTIC-RESISTANCE OF AEROMONAS SPP ISOLATED FROM FRESH-WATER PRAWN MARKETED IN DHAKA, BANGLADESH, Microbiology and immunology, 38(10), 1994, pp. 773-778
Aeromonas spp. were isolated from gills, swimmerets, eggs, stomachs an
d ventral muscles of freshwater prawns (Macrobrachium malcolmsonii) av
ailable in the local fish market of Dhaka, Bangladesh. The density of
Aeromonas spp. on these different body parts of the prawn samples rang
ed from 1.1 0.2 X 10(4) to 1.5 +/-0.16 x 10(7) cfu per gram. The viabl
e counts of aeromonads, fecal coliforms (FC) and Escherichia coli grad
ually increased in prawn samples when stored at 4 C. At - 20 C, the vi
able counts gradually decreased and became zero on the 12th day of sto
rage. The isolation of A. sobria (56%) was more frequent than that of
A. hydrophila (31%) and A. caviae (13%). In the rabbit ileal loop (RIL
) model, fluid accumulation induced by live cultures and cell-free cul
ture filtrates of 11 strains ranged from 0.5 to 1.5 and 0.5 to 1.7 ml/
cm of gut, respectively. Of 11 enterotoxigenic strains, 7 were A. sobr
ia and 4 were A. hydrophila. Enterotoxigenicity correlated with hemoly
tic activity on blood agar. All enterotoxigenic strains were uniformly
sensitive to chloramphenicol and gentamicin and resistant to novobioc
in and vancomycin. Isolation of enterotoxigenic and antibiotic-resista
nt Aeromonas from these prawn samples indicates possible public health
problems for their handlers as well for raw prawn consumers.