IDENTIFICATION AND ANTIBIOTIC PROFILIING OF GRAM-NEGATIVE BACTERIA ISOLATED FROM CULTURED CATFISH (Clarias anguillaris Linnaeus 1758 and Heterobranchus bidorsalis Geoffroy 1809)

Abstract

The present study was conducted to isolate and identify gram-negative bacilli from some African catfish species
and to evaluate the antimicrobial susceptibility of the isolates with a view of making suggestions on treatments.
One hundred and four apparently healthy catfishes (Clarias anguillaris and Heterobranchus longifilis) were
obtained where samples for bacterial cultures from the skin and gastrointestinal tract of the fish. Bacteria species
were identified using standard culture method and biochemical tests respectively. This was followed by
antimicrobial susceptibility test for the bacteria identified using agar disc diffusion method. A total of 8 genera
and 10 species of non-enteric gram-negative rods, and 6 genera and 7 species of Enterobacteriaceae were
identified. Biochemical variations were observed within the following species: Klebsiella pneumoniae, Proteus
mirablis, Enterobacter agglomerans, Aeromonas hydrophila, Alcaligenes faecalis type II, Flavobacterium
menongosepticum, Vibrio alginolyticus, Pseudomonas fluorescens-25 and Pseudomonas fluorescens-35.
Multidrug resistance to two or more antibacterial agents was observed for 89% of the isolates tested. Specifically,
high susceptibility rates to ciptrofloxacin (93%) and gentamycin (75%) by the isolates were observed. Drug
preparations containing ciprofloxacin and gentamycin could be recommended for use in fish culture for bacterial
diseases incriminated by these bacteria.
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