Antimicrobial susceptibility of flavobacteriaceae isolates from nile tilapia (oreochromis niloticus) in Tanzania
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal of Microbiology Research
Abstract
This study aimed to assess antimicrobial susceptibility of members of the family Flavobacteriaceae
isolated from Nile tilapia (Oreochromis niloticus). Antimicrobial susceptibility of 67 Flavobacteriaceae
isolates originating mainly from ponds and Lake Victoria against 19 antimicrobial agents was
determined by the broth micro dilution method. Overall, most isolates were susceptible to enrofloxacin
(97%; MIC 90 2 μg/ml) followed by novobiocin (85%, MIC 90, 4 μg/ml) and the aminoglycoside streptomycin
(85%; MIC 90 , 128 μg/ml). Some isolates were also susceptible towards trimethoprim/sulfamethoxazole
(77.6%), neomycin and florfenicol both at 62.7%. Susceptibility levels were low for tylosin tartrate
(32.8%), clindamycin and sulphathiazole both at (23.9%), ceftiofur (6%), spectinomycin (6%) and
tetracyclines/oxtetracyclines (4.5%). In contrast, β-Lactams (amoxicillin, penicillin), gentamycin and
erythromycin exhibited very poor activity against Flavobacteriaceae isolates. The extent of antimicrobial
susceptibility did not vary significantly among isolates from farmed and wild fish isolates (P > 0.01). The
highest Multiple Antimicrobial Resistance (MAR) index was observed in Chryseobacterium indologenes
(0.89) and the lowest in Chaetoderma indicum isolates (0.32). Our results indicate that most of
Flavobacteriaceae isolates are multidrug resistance, and this may be associated with intrinsic
resistance mechanisms to a broad range of antimicrobial agents. However, the need remains to
carryout in-depth study to understand better the underlying genetic mechanisms given that the
magnitude and trend for susceptibility was comparable between isolates from aquaculture and
fisheries. The findings from this study give us insight into appropriate choice of antimicrobial agents
for effective treatment of infections caused by these isolates.
Description
Journal article
Keywords
Aquaculture, Fisheries, Intrinsic resistance, Minimum inhibitory concentrations, Ponds, Lake Victoria