Comparison of the prevalence of antibiotic-resistant Escherichia coli isolates from commercial-layer and free-range chickens in Arusha district, Tanzania

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.

Caractérisation d’<em>Escherichia coli</em> résistant aux antibiotiques dans différents systèmes avicoles de la province de l’Est et de la ville de Kigali au Rwanda

“…A similar observation was made by Naliaka (2011) who reported identical rates of multiple antibiotic resistance in different poultry farming systems in Kenya. On the contrary, in Tanzania, a clear difference of resistance to different antibiotics was noted between free-range poultry farms and commercial layer farms (Rugumisa et al, 2016). The findings of this study can be explained by the possibility that poultry in the visited free-range farms might be exposed to populations of resistant bacteria in the environment (Wellington et al, 2013).…”

“…The presence of antibiotic resistant E. coli isolates in poultry farms has also been documented in different African countries (Kikuvi et al, 2006;Majalija et al, 2010;Naliaka, 2011;Hamisi et al, 2012;Zeryehun and Bedada, 2013;Mshana et al, 2013;Rugumisa et al, 2016).…”

“…But in other African countries, several studies have established the prevalence of resistant E. coli strains in poultry farms (Kikuvi et al, 2006;Majalija et al, 2010;Naliaka, 2011;Hamisi et al, 2012;Alonso et al, 2017). Other studies showed differences in the antibiotic resistance of E. coli between various farming systems (Okoli, 2006;Naliaka, 2011;Rugumisa et al, 2016). Investigations of antibiotic resistance of E. coli are useful to identify types of resistance present in the region and better understand the challenge to establish appropriate and effective interventions (Omulo et al, 2015).…”

The Role of Mobile Genetic Elements in the Spread of Antimicrobial-Resistant Escherichia coli From Chickens to Humans in Small-Scale Production Poultry Operations in Rural Ecuador

“…A small number of studies have studied AMR patterns in chickens and/or humans associated with small-scale production operations in developing countries (14)(15)(16). We add a new a Models compared isolates from humans associated with small-scale production birds (n = 45) to isolates from humans associated with household birds in villages without small-scale production operations (n = 369) and humans associated with household birds in villages with small-scale production operations (n = 385) to isolates from humans associated with household birds in villages without small-scale production operations (n = 369).…”

“…However, poultry farms worldwide are dominated by small-scale production operations (<100 birds), particularly in developing nations where poultry are raised for income and/or household consumption (12,13). While a small number of studies have documented high levels of AMR in poultry in small-scale production operations (14)(15)(16), not all of these studies have appropriate nonproduction bird or human comparisons (nonclinical, from the immediate surrounding community), and so less is known about AMR development and transmission within these settings.…”