Prevalence of Transferable Oxytetracycline Resistance Factors in Aeromonas hydrophila in Fish Hatcheries
Prevalence of Transferable Oxytetracycline Resistance Factors in Aeromonas hydrophila in Fish Hatcheries
Date
2013
Authors
Bharathkumar, G.
Abraham, T. Jawahar
Journal Title
Journal ISSN
Volume Title
Publisher
Society of Fisheries Technologists (India)Cochin
Abstract
The distribution of motile aeromonads and
prevalence of transferable oxytetracycline resistance
factors in Aeromonas hydrophila of Indian major carp
and catfish hatcheries in West Bengal, India were
studied. Counts of motile aeromonads in carp
hatching pool water (4.23 - 4.54 log cfu ml-1), carp
larval rearing water (3.36 - 3.93 log cfu ml-1) and
catfish larval rearing water (5.41 - 5.85 log cfu
ml-1) of different hatcheries did not vary much. The
motile aeromonad counts in the range of 2.81 - 4.28
log cfu carp larva-1 and 6.08 - 6.69 log cfu g-1 catfish
larvae were recorded. The sensitivity of 48
Aeromonas strains to six antibiotics was observed
to be in the following descending order: gentamycin,
chloramphenicol, ciprofloxacin, nitrofurantoin, oxytetracycline
and co-trimoxazole. The incidence of
multiple antibiotic resistance (MAR) in motile
aeromonads was significantly high (p<0.05) in
catfish hatcheries (95%) than in carp hatcheries
(41%). The prevalence of MAR in A. hydrophila
(69%) was high, but not significant (p>0.05) than
in A. caviae (55%). The mutation frequency of A.
hydrophila strains to oxytetracycline (25 μg ml-1)
was in the range of 6.71×10-9 - 1.60×10-6. The
oxytetracycline resistance factors of size 20.13 and
25.41 kb from A. hydrophila were transferred to
Escherichia coli K12 at a frequency of 2.70×10-6 -
5.35×10-3. It is probable that these bacteria carrying
resistant factors may be the source of spreading
antibiotic resistance to other environmental and
pathogenic bacteria, which share the same aquatic
environment.
Description
Keywords
Aeromonas hydrophila, fish hatchery, antibiotic resistance, oxytetracycline, mutation frequency, R-plasmids
Citation
Fishery Techn 50(4):324-330