Antibiotic Resistance in Escherichia coli from Broiler Chickens After Amoxicillin Treatment in an Experimental Environment

Abstract

Groupwise antibiotic treatments are common in broiler chicken production. They induce selection for antibiotic resistance in commensal Escherichia coli. This study aimed to investigate antibiotic resistance after individual (I, drenching) or groupwise treatment (G, by water) with amoxicillin, and after contact with I or G (KI or KG), compared with untreated broilers without contact with treated broilers (C), and pretreatment values. Finally, we compared antibiotic resistance from broilers (G) after a second treatment, with a treatment in the contact animals (KG), and a first treatment in the control animals (C). Resistance to ampicillin and other antibiotics was significantly increased in groups G and I within 2 days, suggesting (co-)selection of resistance. The increase was lower in groups KI, KG, and C during the first treatment (days 1-5). The increased resistance in group C was interpreted as a change in the microbiota after initial moving and first feeding. After treatment, resistance rates decreased to initial or lower values in all groups. During the second treatment period (days 34-38), all three groups' (G, KG, and C) resistance levels increased to equally high levels. Cephalosporin resistance was low, and did not change over the experimental period. On days 3 and 38, resistance rates of E. coli from duodenum, jejunum, and cecum did not differ between segments and treatment routes. Overall, the baseline levels of antibiotic resistance in E. coli were high. Amoxicillin triggered an increase in resistance levels, irrespective of the mode of treatment. Substantial resistance dynamics in untreated controls warrant further investigation.

Long-term chemically protected sodium butyrate supplementation in broilers as an antibiotic alternative to dynamically modulate gut microbiota

“…Usually, the inflammatory response coincides with raised levels of pro-inflammatory cytokines, which could be suppressed by the antibiotic treatment ( Hu et al, 2020 ). Previous studies described that the production of pro-inflammatory cytokines such as IL-6 and TNF-α was restrained after antibiotics treatment in the broilers such as Enterococcus cecorum ( Schreier et al, 2022 ) or Escherichia coli ( Burow et al, 2020 ) infection. Whereas, long-term antibiotics exposure induced hyperresponsive of intestinal macrophages and T cell dysfunction, in turn producing excess inflammatory cytokines ( Scott et al, 2018 ).…”

Susceptibility of Commensal E. coli Isolated from Conventional, Antibiotic-Free, and Organic Meat Chickens on Farms and at Slaughter toward Antimicrobials with Public Health Relevance

“…In our work, the resistance to chloramphenicol described in the conventional samplings could be explained by the possible effects of repeated antibiotic treatments with amoxicillin, as described for broilers [ 52 ]. Recently, Burow et al [ 53 ] have experimentally demonstrated an increase in resistance towards several antimicrobials (tetracycline, ciprofloxacin, nalidixic acid, gentamicin) after oral administration of amoxicillin, which is commonly used in poultry practice. Finally, ESBL E. coli strains were higher at slaughter than in the farm.…”

First isolation of verocytotoxin-producing Escherichia coli O157:H7 from sports animals in Southern Thailand

“…As we understand, the use of antimicrobial agents for therapeutic and especially non-therapeutic purposes for farm animals will promote the incidence of antimicrobial agent resistance through selective pressure. The majority of previous research was conducted on farm animals whose sole purpose was to produce food [42][43][44]. Antimicrobial agents used in animal farms for food production are not intended to promote growth; however, if infectious diseases are not treated promptly, they can negatively impact the productivity and economy of affected businesses.…”