Abstract
This study discussed the use of antimicrobials in the commercial chicken production system and the possible factors influencing the presence of Extended-spectrum β-lactamase (ESBL)/AmpC producers strains in the broiler production chain. The aim of this study was to perform longitudinal monitoring of ESBL-producing and fosfomycin-resistant Escherichia coli from poultry farms in southern Brazil (Paraná and Rio Grande do Sul states) and determine the possible critical points that may be reservoirs for these strains. Samples of poultry litter, cloacal swabs, poultry feed, water, and beetles (Alphitobius sp.) were collected during three distinct samplings. Phenotypic and genotypic tests were performed for characterization of antimicrobial resistant strains. A total of 117 strains were isolated and 78 (66%) were positive for ESBL production. The poultry litter presented ESBL positive strains in all three sampled periods, whereas the cloacal swab presented positive strains only from the second period. The poultry litter represents a significant risk factor mainly at the beginning poultry production (odds ratio 6.43, 95% confidence interval 1–41.21, p < 0.05). All beetles presented ESBL positive strains. The predominant gene was blaCTX–M group 2, which occurred in approximately 55% of the ESBL-producing E. coli. The cit gene was found in approximately 13% of the ESBL-producing E. coli as AmpC type determinants. A total of 19 out of 26 fosfomycin-resistant strains showed the fosA3 gene, all of which produced ESBL. The correlation between fosA3 and blaCTX–M group 1 (blaCTX–M55) genes was significant among ESBL-producing E. coli isolated from Paraná (OR 3.66, 95% CI 1.9–9.68) and these genetic determinants can be transmitted by conjugation to broiler chicken microbiota strains. Our data revealed that poultry litter and beetles were critical points during poultry production and the presence of fosfomycin-resistant strains indicate the possibility of risks associated with the use of this antimicrobial during production. Furthermore, the genetic determinants encoding CTX-M and fosA3 enzymes can be transferred to E. coli strains from broiler chicken microbiota, thereby creating a risk to public health.
Highlights
Antimicrobial resistance is one of the most alarming public health problems in recent years
E. coli samples grown in MacConkey agar (MC)/CTX were obtained from poultry litter in all periods in both states, whereas it was only present in cloacal samples isolated from the second period (Table 1)
Among the 117 samples, ESBL-producing E. coli strains were detected in poultry litter in all sampling periods: first period, second period, and third period
Summary
Antimicrobial resistance is one of the most alarming public health problems in recent years. The widespread use of antimicrobial drugs, both in humans and animals (including livestock animals), has favored the selection and dissemination of bacterial resistance worldwide (World Health Organization, 2014). Extended-spectrum β-lactamase (ESBL) and AmpC-like enzymes are among the best-known mechanisms of bacterial resistance, which are both mediated by plasmid genes (Ceccarelli et al, 2019) and can be achieved through the horizontal transfer of mobile genetic elements, in both intestinal and extra-intestinal environments (Lazarus et al, 2014). ESBL/AmpC enzymes are found in Enterobacteriaceae family members, such as Escherichia coli, which have often been isolated in livestock, especially during poultry production (Blanc et al, 2006; Carattoli, 2008; Li et al, 2015). Among the most relevant β-lactamases, CTX-M is one of the main enzymes present in E. coli that colonize and infect poultry (Olsen et al, 2014)
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