Antimicrobial inhibition monitor

An adaptation of the CFT for use with 96-well microtiter plates is the so-called antimicrobial inhibition monitor (AIM-96). This test has been recently evaluated for potential application in muscle analysis (71). Unformnately, its sensitivity for most antimicrobials, with the exception of penicillin G, was not found sufficient to monitor at MRLs and, thus, the manufacturer of the test is continuing developmental work. 

The calf antibiotic and sulfa test (CAST), the fast antimicrobial screen test (FAST), and the swab test on premises (STOP) are all bacterial inhibition tests developed at the US Department of Agriculture Food Safety and Inspection Services to screen kidneys for antimicrobial drug residues at slaughter (97-101). For CAST and FAST, an incision is made with a knife, whereas for STOP the tissue is macerated with the shaft of the swab. For all three tests, cotton swabs are inserted into kidney tissue to soak up fluids. Swabs are then incubated on inoculated medium with a disc containing an antibiotic standard used to monitor the viability of the organism and its growth inhibition. 

Bioautography is a method developed for the study and analysis of biologically active substances from simple samples to complex biological matrices. Antimicrobial activity is the monitored parameter, and it can be either growth-inhibiting or growth-promoting. 

A preservative is a substance that extends the shelf-life of drug products by preventing oxidation or inhibiting microbial growth.14 Preservatives must be monitored in the products since they are considered to be active components. Generic HPLC assays are typically developed for preservatives such as buty-lated hydroxytoluene (BHT), an antioxidant for solid dosage forms, and antimicrobials such as parabens, sodium benzoate, or sorbic acid in liquid formulations. For these additive components, typical assay specifications are 85-115% of label claim. 

---