Validation of prototypes for elimination of antibiotics from tissue and liquid samples undergoing microbiological analysis

Purpose: To validate single-use prototypes for elimination of antibiotics from tissue and liquid samples undergoing microbiological analysis to prevent interference with microbial growth.

Methods: The “Syringe ResEP” and “Tissue ResEP” prototypes were used for liquid and tissue samples, respectively. The efficacy of antibiotic removal from 5 ml of BASE.128 (AL.CHI.MI.A.S.r.l.), two bank’s homemade antibiotic cocktails and cardiovascular tissue homogenates was determined by HPLC after 5, 10, 30, 60 min. of treatment. The recovery of S. Aureus, P. Aeruginosa, C. Albicans, B. Subtilis, A. Niger and C. Sporogenes was determined by dilution plating of inoculants containing 1-10, 10-100 and 100-1000 CFU, 20 min. after treatment.

Results: The HPLC analysis of the “Syringe ResEP” treated samples showed complete antibiotic removal from the BASE.128 within 5 min. of treatment. The bank’s homemade antibiotic cocktails showed removal of 95% of antibiotics within 15 min. The “Tissue ResEP” prototype, under continuous stirring, cleared tissue samples decontaminated with either BASE.128 or bank cocktails from antibiotics within 1 h. With both prototypes, total bacterial recovery was obtained for all investigated inoculants.

Conclusions: The “Syringe ResEP” was validated for easy and quick removal of antibiotic residues from liquid samples undergoing microbiological analysis showing complete microbial recovery and high specificity for BASE.128 medium and BASE.128 treated tissue samples. Futher experiments are in progress for complete validation of “Tissue ResEP”. The prototypes removed efficiently the antibiotic residues also from samples treated with bank’s homemade cocktails.