Determination of Antibiotic Resistant Bacteria and Antibiotic Residues in Red Meat

Background: Retail red meat may act as a source of foodborne pathogens, antimicrobial resistant bacteria, and antibiotic residues, posing a significant public health concern in Bangladesh. Objectives: This study aimed to isolate and identify major bacterial pathogens from retail red meat, determine their antimicrobial susceptibility patterns, assess the prevalence of antibiotic resistant bacteria, and detect antibiotic residues in meat samples. Methods: A cross-sectional study was conducted from January to June 2019 using 60 retail red meat samples (20 cattle, 20 goat, and 20 buffalo) collected from Rajshahi and Naogaon districts. Bacterial isolates were identified using standard cultural, morphological, staining, and biochemical techniques. Antimicrobial susceptibility was evaluated by the Kirby Bauer disc diffusion method according to CLSI guidelines. Antibiotic residues were screened in 15 representative samples using thin layer chromatography (TLC). Results: Overall prevalence of Escherichia coli, Salmonella spp., and Staphylococcus aureus was 10.0%, 13.3%, and 28.3%, respectively. E. coli showed complete resistance to penicillin (100%) and high resistance to amoxicillin (83.3%), while remaining highly susceptible to ciprofloxacin (83.3%) and gentamicin (66.7%). Salmonella spp. exhibited highest resistance to penicillin (87.5%) and tetracycline (75.0%), whereas gentamicin (87.5%) and ciprofloxacin (75.0%) remained the most effective agents. S. aureus demonstrated marked resistance to penicillin (94.1%), ampicillin (58.8%), tetracycline (47.1%), and amoxicillin (47.1%), but high susceptibility to gentamicin (88.2%) and ceftriaxone (70.6%). TLC detected ciprofloxacin and oxytetracycline residues in one cattle meat sample each (6.7%). Conclusions: Retail red meat marketed in the study areas harbored multidrug-resistant bacterial pathogens and detectable antibiotic residues, highlighting potential risks to food safety and public health. Continuous surveillance, prudent antimicrobial use, improved slaughterhouse hygiene, and strict compliance with antibiotic withdrawal periods are essential to minimize antimicrobial resistance and residue contamination.