Five-assay microbiological system for the screening of antibiotic residues

• Published in: Revista argentina de microbiología 2019-10, Vol.51 (4), p.345-353
• Main Authors: Tumini, Melisa, Nagel, Orlando G., Althaus, Rafael L.
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - analysis; Antibiotic; Antibiótico; Bioassay; Bioensayo; Biological Assay; Clasificación; Classification; Detección; Detection; Drug Residues - analysis; Leche; Microbiological system; Microbiological Techniques; Milk; Milk - chemistry; Sistema microbiológico
• ISSN: 0325-7541
• DOI: 10.1016/j.ram.2019.01.002

A novel microbiological system in microtiter plates consisting of five bioassays is presented for the detection and classification of antibiotic residues in milk. The bioassays were optimized for the detection of beta-lactams (Bioassay B: Geobacillus stearothermophilus), macrolides (Bioassay M: Bacillus megaterium with fusidic acid), tetracyclines (Bioassay T: B. megaterium with chloramphenicol), quinolones (Bioassay Q: Bacillus licheniformis) and sulfamides (Bioassay QS: B. licheniformis with trimethoprim) at levels near the maximum residue limits (MRL). The response of each bioassay was interpreted visually (positive or negative) after 4–5.5h of incubation. The system detects and classifies beta-lactams (5μg/l of amoxicillin, 4μg/l of ampicillin, 36μg/l of cloxacillin, 22μg/l of amoxicillin, 3μg/l of penicillin, 114μg/l of cephalexin, 89μg/l of cefoperazone and 116μg/l of ceftiofur), tetracyclines (98μg/l of chlortetracycline, 92μg/l of oxytetracycline and 88μg/l of tetracycline), macrolides (33μg/l of erythromycin, 44μg/l of tilmicosin and 50μg/l of tylosin), sulfonamides (76μg/l of sulfadiazine, 85μg/l of sulfadimethoxine, 77μg/l of sulfamethoxazole and 87μg/l of sulfathiazole) and quinolones (94μg/l of ciprofloxacin, 98μg/l of enrofloxacin and 79μg/l marbofloxacin). In addition, the specificity values were high for B, T, Q (99.4%), M (98.8%) and QS (98.1%) bioassays. The control of antibiotics through this system can contribute to improving the quality and safety of dairy products. Se presenta un novedoso sistema microbiológico en placas de microtitulación compuesto por 5 bioensayos para la detección y clasificación de residuos de antibióticos en leche. Los bioensayos fueron optimizados para la detección de betalactámicos (bioensayo B: Geobacillus stearothermophilus), macrólidos (bioensayo M: Bacillus megaterium con ácido fusídico), tetraciclinas (bioensayo T: Bacillus megaterium con cloranfenicol), quinolonas (bioensayo Q: Bacillus licheniformis) y sulfamidas (bioensayo QS: Bacillus licheniformis con trimetoprima), a niveles cercanos a los límites máximos de residuos (LMR). La respuesta de cada bioensayo se interpretó visualmente (positiva o negativa) después de 4 a 5,5h de incubación. El sistema detecta y clasifica betalactámicos (5μg/l de amoxicilina, 4μg/l de ampicilina, 36μg/l de cloxacilina, 22μg/l de amoxicilina, 3μg/l de penicilina, 114μg/l de cefalexina, 89μg/l de cefoperazona y 116μg/l de ceftiofur), tetraciclinas (98μg/l de clortetraciclina