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.
Introduction
Irrational use of antimicrobials has now been identified as a major global health threat especially in developing countries where regulation of antibiotic use is not adequately considered. One such unregulated application is the feeding of antibiotics to food-chain animals such as poultry. The benefits of antibiotic use in poultry feed and water, has been practiced and supported for many years. However, the negative impacts of this practice, without considering the withdrawal period, may lead to the risk of antibiotic residues existing in meat tissues. The presence of these residues in food poses a risk to human health because it may be associated with allergic reaction, adverse effect on gut flora and the development of antimicrobial resistance.
A number of studies have demonstrated that bacterial resistance to new antimicrobials can emerge due to selective pressure resulting from their un-regulated use, leading to increasing resistance in human and animal isolates over time. Furthermore, a direct relationship between antibiotic consumption and the emergence and dissemination of resistant bacterial strains in humans and the environment have been shown in many studies. Consumption of antibiotic-treated livestock was highlighted as a major cause of the spread of resistant bacteria to humans. Transmission of resistant bacteria to humans by farm animals was confirmed when high rates of antibiotic resistance were found in the intestinal flora of both farm animals and farm workers. Molecular characterization methods have recently shown that resistant bacteria and resistant genes in food chain animals reach the human body through consumption of their meat.
Food chain animals may serve as important reservoirs of resistant zoonotic bacteria that can colonize the human intestinal tract and transfer resistance genes to the commensal flora. Salmonella is a frequent enteric pathogen in poultry, and is one of the major foodborne pathogens of zoonotic importance to public health. Among Salmonella spp, S. enterica is a ubiquitous pathogen with a large host range causing various diseases. Hosts include food chain animals or companion animals and humans, and disease symptoms range from limited gastroenteritis to invasive systemic infections with a high mortality rate.
Animal-derived Salmonella is highly pathogenic and have been commonly implicated in outbreaks of gastroenteritis in Egyptian patients, resulting from the consumption of contaminated food.
The presence of antibiotic residues in chicken meat and chicken products has been reported in several Egyptian cities. Understanding the complex interplay between antibiotic use and the effects of residues in food chain animals such as chickens, in relation to the development of antibiotic resistance is critical to implementing effective approaches to mitigate this growing public health threat. Therefore, it is of utmost significance to study bacterial content of zoonotic importance and residual presence of antibacterial substances in poultry products. The current study investigated the relationship between the presence of three residual antibiotics in commercial chicken meat and antibiotic resistance of Salmonella isolates from the same chicken samples. This work aims to highlight the multifaceted nature of antibiotic use and emphasizes the importance of adopting sustainable practices in the poultry industry to monitor and control residual levels of antibiotics, significantly, to protect the effectiveness of antibiotics for future generations.
by: scientific reports, Hala R. Ali, Esraa G. Hefny, Naglaa F. Koraney, Samah F. Ali, Mohamed I. AbdAllah, Mai A. Fadel, Sara M. Elnomrosy & Momataz A. Shahein