Screening for Antibiotic Residues In Bovine's Rumen And Abomasum Popularly Known As Towel From Four-Selected Open Markets In Ghana Using Bioassay Method

The consumption of bovine rumen and abomasum (locally known as towel) is widespread in Ghana, particularly in urban areas. However, concerns about antimicrobial resistance and antibiotic residues in these food products have raised significant public health concerns due to indiscriminate antibiotic use in cattle farming. This study employed the agar well diffusion bioassay screening method to provide preliminary surveillance data on antibiotic residue prevalence. A total of 120 samples (60 rumen and 60 abomasum) were collected from four major markets (Nima, Mallam, Kaneshie, and Ashiaman) in the Greater Accra region of Ghana. Samples were analyzed for antibiotic residues using the agar well diffusion bioassay with Bacillus subtilis ATCC 6633 as the test organism. Additionally, bacterial isolates were tested for antimicrobial susceptibility using the Kirby-Bauer disk diffusion method against commonly used antibiotics. Antibiotic residues were detected in 34.2% (41/120) of the samples tested . Proteus species and Bacillus species isolated from residue-containing samples showed varying degrees of antibiotic resistance. Multi-drug resistance was observed in 86.7% (81/93) of the isolates, with complete resistance to ampicillin (100%) being particularly notable. Specifically, 49 of 56 Bacillus species isolates (87.5%) and 32 of 37 Proteus species isolates (86.5%) exhibited resistance to three or more antibiotic classes. Geographic variations in resistance patterns were observed across the different market locations, though these differences were not statistically significant. All isolates showed susceptibility to gentamicin and ciprofloxacin. The high prevalence of antibiotic residues and multi-drug resistant bacteria in bovine rumen and abomasum from Ghanaian markets poses significant public health risks. These findings highlight the urgent need for enhanced antibiotic stewardship in livestock production, improved regulatory monitoring, and implementation of proper withdrawal periods in Ghana's cattle farming sector.