The use of antimicrobials in poultry farming began in the 1940s and has since played a pivotal role in supporting the growth of the global poultry industry, where bacterial infections in broiler flocks can cause production losses of up to 20% [1]. Poultry currently ranks as the second most consumed meat worldwide, accounting for approximately 36% of total meat production [2]. The increasing demand for poultry products such as chicken meat and eggs is largely attributed to their affordability, nutritional value, and wide consumer acceptance [3].
In modern poultry production, veterinary antimicrobials are extensively used for the prevention and treatment of infections, stress reduction, and growth promotion [4]. However, improper administration and failure to observe recommended withdrawal periods can lead to the accumulation of antimicrobial residues in edible tissues and eggs [5, 6]. These residues may occur in both egg white and yolk following therapeutic treatment or accidental contamination of feed [7]. Consumption of residue-contaminated products can cause hypersensitivity reactions in susceptible individuals, disrupt the intestinal microbiota, and contribute to the development of antimicrobial resistance [8]. Despite rules and regulations in Nepal, misuse of veterinary drugs remains widespread; an estimated 71% of poultry farmers obtain antimicrobials without veterinary prescription or supervision [9]. Various antibiotic classes—including aminoglycosides, tetracyclines, β-lactams, fluoroquinolones, macrolides, nitrofurans, sulfonamides, and trimethoprim—have been detected as residues in animal-derived foods such as meat, milk, and eggs, posing toxicological and public health risks [10].
Quinolones, critically important antimicrobials, pose public health risks due to potential antimicrobial resistance, allergic reactions, and other toxicities when residues persist in food. This study aimed to qualitatively and quantitatively assess quinolone residues in chicken meat and eggs supplied to Kathmandu, Nepal. Additionally, data on antibiotic usage trends were collected through a standardized questionnaire using Epicollect + Android application. A total of 120 chicken meat and 120 eggs were collected from five designated sectors. Initial screening for quinolone residues was performed using Enzyme-Linked Immunosorbent Assay, and samples exceeding the maximum residue limit (MRL) were further analyzed using High-Performance Liquid Chromatography.
Fluoroquinolones, synthetic broad-spectrum antimicrobials, are among the most widely used agents in veterinary medicine. Enrofloxacin, the first fluoroquinolone developed for animal use, is commonly applied to treat systemic bacterial infections of the respiratory, gastrointestinal, urinary, and integumentary systems [11, 12]. Ciprofloxacin, its principal metabolite, exhibits similar antibacterial activity against both Gram-positive and Gram-negative bacteria with fewer adverse effects. However, excessive or indiscriminate use of these drugs can result in persistent residues in animal products and promote the emergence of drug-resistant pathogens, raising significant food safety and public health concerns [13]. Notably, due to the rise of fluoroquinolone-resistant Campylobacter species associated with human infections, the U.S. Food and Drug Administration banned the use of Enrofloxacin in poultry in 2005 [14]. Many countries have since established Maximum Residue Limits (MRLs) and withdrawal periods for fluoroquinolones to ensure food safety, such as an MRL of 100 µg/kg for the sum of enrofloxacin and ciprofloxacin in muscle tissue [15].
In Nepal, poultry contributes approximately 8% of total meat production, with over 1,000 broiler farms supplying around 150,000 kg of chicken meat daily, ranking the country 112th globally in poultry production [16]. Despite this growth, limited data exist regarding antibiotic residue levels in poultry products, raising concerns about food safety and public health. Therefore, this study aims to assess the presence and concentration of antimicrobial residues, particularly fluoroquinolones, in chicken meat and eggs marketed within the Kathmandu Valley. The outcomes are expected to provide essential evidence to inform national policies promoting the prudent use of veterinary antimicrobials. Furthermore, the findings will contribute to raising awareness among veterinarians, feed consultants, poultry producers, and consumers, supporting the broader objectives of the One Health initiative by integrating human, animal, and environmental health perspectives.
Quinolone residues were detected in 88.3% of chicken meat and 80% of egg samples. Three chicken meat samples from Kathmandu exceeded the MRL (> 100ppb), with Enrofloxacin found in commercial and education sectors and both Enrofloxacin and Ciprofloxacin in the health sector. In eggs, residue prevalence was 83.9% in Kathmandu followed by Bhaktapur (76.9%) and Lalitpur (65%). Household eggs had the most residues (100%), and the education sector had the least (66.7%) (p = 0.0219). These findings indicate widespread and unregulated quinolone use in poultry production, highlighting the urgent need for prudent antibiotic stewardship to reduce antimicrobial resistance and associated health risks.
Source;
Shrestha, N., Layalu, S., Amatya, S. et al. Quinolones residue in poultry meat and eggs; an alarming public health issue in Nepal. BMC Res Notes 19, 49 (2026). https://doi.org/10.1186/s13104-025-07627-z
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