Antibiotic residues correlate with antibiotic resistance of Salmonella typhimurium isolated from edible chicken meat

Abstract

Irrational application and overuse of antibiotics in poultry production is associated with antibiotic residues in meat tissues which lead to the development of antibiotic resistance in pathogenic bacteria such as Salmonella. This study investigated the co-existence of multi-drug resistant Salmonella typhimurium (S. typhimurium) and residual traces of antibiotics in chilled chicken meat collected from Fayoum province in Egypt. Our data reported that 22.2% of chicken meat and liver were contaminated with S. typhimurium with 100% being drug resistant to a wide range of antimicrobials including tylosin, chloramphenicol, and oxytetracycline (OTC). The residual analysis of chicken meat samples revealed that they contained residues of 3antibacterial drugs including tylosin, chloramphenicol, OTC and its metabolite (4-epi-OTC). The statistical analysis of obtained data also revealed a relationship between S. typhimurium resistance and the presence of antibiotic residues in chicken samples, as isolates derived from samples with residual drug content higher than maximum residue levels (MRL) were found to be resistant to the same antibiotic. This confirms the importance of integrating sustainable practices in the veterinary field with a strict commitment to monitoring the bacterial content and residual antibiotics in foods of animal origin before marketing them, to protect the effectiveness of antibiotics for future generations.

Keywords: S. typhimurium; Salmonella; Antibiotic residues; Antimicrobials.

Fig. 1

The PCR amplicon of Inva gene in Salmonella isolates with positive band at 284 bp. Lane M: is 100 bp ladder, Lane 1–4, 7 and10–13: positive, Lane 5, 6 and 8: negative, −Ve: negative control and + Ve control.

Fig. 2

The prevalence rate of S. enterica serovar typhimurium among the different tested chicken parts.

Fig. 3

Phylogenetic analysis of invasion protein (inva) gene, of S. enterica subsp. The partial nucleotide sequences from different strains of S. enterica subsp., were obtained via NCBI Resource. The phylogenetic analysis was performed using MEGA6. Construction with the maximum-likelihood (ML) analysis of evolutionary distances determined by the GTR + G + I model. NJ and ML bootstrap (×1000) Consensus neighbour-joining trees were obtained from 1000 bootstrap replicates. The red-rhombus indicates strains under study.

Fig. 4

Nucleotide identities of partial Inva gene, compared to other selected Egyptian strains, field, and strains available on GenBank.

Fig. 5

The incidence of antibiotics residues among the analyzed chicken parts (L: Liver, B: Breast & T: Thigh).

Fig. 6

Average concentrations of antibiotic residues in tested chicken samples (L: Liver, B: Breast & T: Thigh) from Fayoum.