Immunoassays for the rapid detection of gentamicin and micronomicin in swine muscle.

A monoclonal antibody (mAb)-based ELISA and strip test for gentamicin (GEN) and its analogue micronomicin (MIN), are reported in this study. The conjugate gentamicin-glutaraldehyde-bovine serum albumin (GEN-GDA-BSA) was used as an immunogen. The produced anti-GEN mAB exhibited high cross-reactivity with micronomicin (MIN; 131.2%) and slight or negligible crossreactivity with other aminoglycosides. Based on this mAB, an ELISA and a strip test for GEN and MIN were developed and evaluated. The ELISA showed a 50% inhibition concentration (IC50) of 0.75 ng/mL for GEN and 0.58 ng/mL for MIN. For GEN, the average recoveries at 25-200 microg/kg ranged from 73 to 91%, with intraday CVs of 9-16% and interday CVs of 8-15%. For MIN, the average recoveries ranged from 108 to 131%, with intraday CVs of 10-16% and interday CVs of 8-15%. In contrast, the strip test for GEN or MIN had a detection limit of 5 ng/mL in phosphate-buffered saline and 50 microg/kg in muscle (n=24), and the results could be judged within 10 min. The detection results of incurred samples analyzed by the strip test, ELISA, and HPLC indicated that the two immunoassays correlated well with the HPLC method and could be used as convenient tools for the rapid screening of GEN and MIN residues in swine muscle.