Oxytetracycline-loaded food and toxic manifestations in humans and petsAuthor(s): Alessandro Di Cerbo
According to a recent World Health Organization (WHO) report the term “antimicrobial resistance” is referred to the change of a microorganism once exposed to antimicrobial drugs. Nowadays, antimicrobial resistance represents a serious concern particularly in two correlated fields, i.e. medical and agriculture. In poultry, for instance, antibiotics are used to promote growth and to treat, control and prevent overcrowding diseases. A routine exposure to antibiotics induces a selection for resistant bacteria that can persist on meat and in animal waste with a vertical transmission through maternal generations of breeding stocks. Such bacteria can get in contact with humans in food-animal production facilities, in meat processing plants but also consuming contaminated meat. Recently, Mueller et al. hypothesized that food allergens e.g. beef, fish and chicken could drag antibiotics and hormones thus representing the cause for the onset of dermatological symptoms in cats. Among pharmacologically active substances, tetracyclines (in particular oxytetracycline, OTC) and their metabolites present in meats and meat-based foods for humans and pets were considered and studied. We firstly hypothesized and observed the role of OTC as an underlying cause of some chronic inflammatory pathology. Due to its low cost and high efficacy, OTC is widely employed in the intensive farming of poultry, livestock and aquaculture. However, OTC has a high affinity for calcium, mainly present within bones, and a very low and long clearance in treated animals. Further, pet food production, which mainly relies on poultry by-products, also avails itself as an important percentage of bone meal (20-30%) with a consequent dragging of OTC residues that are frequently found within commercially available diets. Despite the setting of maximum residue limits in foods by Food and Drug Administration and World Health Organization OTC residues may still persist since bone is not considered as an edible tissue, thus making pet food potentially dangerous. We evaluated the toxicity of OTC present within bones of only OTC-treated chicken according to standard withdrawal times and investigated the OTC form responsible for such toxicity.