Comparison of the prevalence of antibiotic-resistant Escherichia coli isolates from commercial-layer and free-range chickens in Arusha district, Tanzania
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Date
2016-09-14
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal of Microbiology Research
Abstract
The antibiotic susceptibility of fecal Escherichia coli isolates from commercial-layer and free-range
chickens in Arusha district, Tanzania were compared. All the chickens were raised by individual
households, but commercial-layer chickens were purchased from commercial vendors, whereas no
systematic breeding system was used to produce free-range chickens. A total of 1,800 E. coli isolates
(1,200 from commercial-layer chickens and 600 from free-range chickens) were tested for susceptibility
to 11 antibiotics by breakpoint assays. All E. coli isolates were susceptible to gentamicin, ceftazidime
and cefotaxime. Isolates from commercial-layer chickens had a high prevalence of resistance (32.4-
74.5%) for amoxicillin, ampicillin, ciprofloxacin, tetracycline, streptomycin, trimethoprim and
sulfamethoxazole, while the prevalence of resistance to these antibiotics was lower (7-31.5%) for freerange
chickens (P<0.05). Both groups had a similar prevalence of resistance to chloramphenicol (1.17-
1.5%; P>0.05). For antibiotic resistant strains, 64.1 and 91.5% of free-range and commercial-layer
isolates, respectively, were resistant to ≥ 2 antibiotics. Commercial-layer chickens harbored
significantly more resistant E. coli isolates (P<0.001) than free-range chickens, consistent with more
exposure to antibiotics when compared with free-range chickens. Efforts should be directed towards
motivating household owners to limit the use of antibiotics when they are investing in these breeds.
Sustainable Development Goals
Research Article published African Journal of Microbiology Research Vol. 10(34), 14 September 2016
Keywords
Antibiotic resistance, commercial-layer, Escherichia coli, free-range