Antimicrobial Susceptibility of Escherichia coli and ESBL-Producing Escherichia coli Diffusion in Conventional, Organic and Antibiotic-Free Meat Chickens at Slaughter

Abstract

As a result of public health concerns regarding antimicrobial resistance in animal-based food products, conventional poultry companies have turned to ‘raised without antibiotics’ (ABF) and organic farming systems. In this work, we evaluated the influence of rearing systems on antimicrobial susceptibility in E. coli and extended-spectrum β-lactamase (ESLB) E. coli diffusion in conventional (C), organic (O) and antibiotic free (ABF) chicken samples collected from cloacal swabs and skin samples in slaughterhouse. The E. coli isolates from conventional (135), antibiotic-free (131) and organic (140) samples were submitted to the Kirby–Bauer method and ESBL E. coli were analyzed by the microdilution test. Conventional samples showed the highest number of strains resistant to ampicillin (89.6%; p < 0.01), cefotaxime (43.7%; p < 0.01), nalidixic acid (57.8%; p < 0.01), ciprofloxacin (44.4%; p < 0.001), and trimethoprim/sulfamethoxazole (62.2%; p < 0.01), with patterns of multi-resistance to three (35.1%) and to four antimicrobials (31.3%), whereas most of the E. coli isolated from antibiotic-free and organic chicken samples revealed a co-resistance pattern (29.2% and 39%, respectively). The highest number of ESBL E. coli was observed in conventional, in both cloacal and skin samples and the lowest in organic (p < 0.001). Our results are consistent with the effect of conventional farming practices on E. coli antimicrobial resistance and ESBL E. coli number, due to the use of antimicrobials and close contact with litter for most of the production cycle.

Antimicrobial Resistance Profile and Extended Spectrum Beta-Lactamase Resistance Genes in Escherichia coli from Poultry Droppings in Nasarawa, Nigeria

“…*MAR isolates are those with resistance to at least two antibiotics [24] From this study, E. coli isolates were more resistant to streptomycin, sulphamethoxazole /trimethoprim, and ampicillin, which is similar to studies by [27], [31], and [32], but less resistant to imipenem, cefotaxime and ceftazidime. This finding is similar to a study by [33].The observed resistance of the E. coli from this study to commonly used antibiotics is not extraordinary as many studies worldwide have reported it [34,35] .…”

Prevalence and Antimicrobial Resistance of Enteropathogenic Bacteria in Yellow-Legged Gulls (Larus michahellis) in Southern Italy

“…Actually, Stedt et al [ 12 ] highlighted a south-to-north gradient in Europe (valid for E. coli from humans, food production animals and gulls), characterized by higher levels of resistance in Mediterranean countries and lower levels of resistance in northern Europe, with few local variations. These results, including ours, reflect the overuse of antibiotics in veterinary and human medicine over the years [ 12 , 14 ], and suggest that gulls might act as vectors but also as victims, acquiring resistant strains that potentially originate from humans or animals, which are often subjected to antibiotic administration [ 37 , 38 ].…”

Genetic Profiles and Antimicrobial Resistance Patterns of Salmonella Infantis Strains Isolated in Italy in the Food Chain of Broiler Meat Production

“…On this matter it should be highlighted that in recent years most of the large Italian conventional poultry-producing companies have progressively turned to antibiotic-free and organic lines of products. However, in an our previous work [ 20 ] we found high prevalence of E. coli commensal strains resistant to tetracycline and nalidixic acid in both in antibiotic free and organic farming due likely to the vertical transmission and/or early contamination at hatch. Furthermore, an external environment contamination by resistant bacteria could be considered in an organic farm.…”