Multiantibiotic residues in commercial fish from Argentina. The presence of mixtures of antibiotics in edible fish, a challenge to health risk assessment.

The occurrence of 46 antibiotics (amphenicols, cephalosporins, dihydrofolate reductase inhibitors, fluroquinolones, macrolides, nitrofurans, penicillins, quinolones, sulfamides and tetracyclines) in Argentinean market fish were investigated by UPLC-MS/MS. Veterinary and human antimicrobials enrofloxacin, clarithromycin, roxithromycin, doxycycline and oxytetracycline were detected in 100% of the samples, being to our knowledge the first report of clarithromycin in edible fish muscle. Maximum Residual Limits were exceeded for at least one antibiotic in 82% of pacú, 57% of shad, 57% of trout and 50% of salmon samples. Chloramphenicol, furazolidone and nitrofurantoin (banned compounds in food items) were detected in 41%, 22% and 4% of the samples, respectively. Based on the estimated daily intake calculation, samples do not pose a serious risk to public health. Further investigation on the chronic impact and risk calculation of the mixture of antibiotics on the aquatic environment and human health is urgently needed.