PATHOGENIC GUT MICROBIOTA ASSOCIATED WITH STRIPED CATFISH, PANGASIANODON HYPOPHTHALMUS CULTURED IN BANGLADESH AND THEIR ANTIBIOTIC SENSITIVITY PATTERN

Abstract

To identify the gut bacteria of Pangasianodon hypophthalmus (striped catfish;
Pangas) using classical and molecular approach was carried out. Total bacterial
count (TBC) in the gut of pangas from farm and market samples were found 5.07
± 1.70 × 106 and 1.40 ± 0.47 × 106 cfu/g, respectively. The gut microbiota of pangas
was dominated by members of the Gram-negative genera. Only three isolates
(MyF1/1, MyF1/4 and GaW1/2) were found to be Gram-positive among the 16
representative isolates. Using 16S rRNA gene sequencing; Bacillus, Macrococcus,
Citrobacter, Aeromonas, Proteus, Klebsiella, Enterobacter, Escherichia and Edwardsiella
were found to be associated with the gut of this fish. Among them, Aeromonas
was the most dominant genus (5 out of 16). Antibiotic sensitivity pattern
reflected that all the isolates were sensitive to gentamycin. Multiple antibiotics
resistant isolates were also identified of which MyF3/13 (identified as Citrobacter
amalonaticus) was found resistant against seven tested antibiotics. The presence of
pathogenic bacteria in fish gut revealed the improper handling practices in fish
market and unhygienic condition in the culture sites which might be a reason of
fish-borne disease outbreaks. On the other hand, widespread use of various
antibiotics in aquaculture without proper awareness may lead to resistance to
multiple antibiotics.