Evaluation of RESEP device treatment for antibiotic removal on homogenized tissues

Purpose: To evaluate the use of RESEP device (ALCHIMIA S.r.l.), intended for antibiotic removal from liquid samples, on tissue homogenates.

Material and method
RESEP treatment of tissues:
– Homogenization: 1 gr in 10 ml of BASE solution with IKA ULTRA TURRAX homogenizer
– 2 passages in RESEP, 20 min/each at RT RESEP was evaluated for the following parameters:
1. Bacterial retention: sterile human fresh aorta fragments were homogenized, contaminated with P.aeruginosa (3 doses) and treated with RESEP.
2. Interference with bacterial growth: sterile human fresh aorta and pericardium fragments were contaminated with P.aeruginosa and S.aureus (3 doses).
3. Antibiotic removal ability: decontamination (BASE 128_125ml/g: 14 h, 37°C) washing (BASE 6,5 ml/g. 2×5 mln, 1x6h, 4°C) and homogenization procedures were applied on sterile porcine cardiovascular tissues. Microbial strains were spiked on RESEP treated/untreated homogenates.
All the homogenates were tested on agar plates for microbal quantification and in BactAlert.

Results: Two sequential passages of the homogenates on RESEP only slightly reduced P.aeruginosa load tested on agar plates. Samples were positive in BacAlert.
P.aeruginosa and S.aures in RESEP treated and untreated homogenates showed similar growth capability on agar plates and were positive in BacAlert.
RESEP-treated homogenates showed a slightly better bacterial recovery than RESEP-untreated samples both in agar plates and in BactAlert.

Conclusions: RESEP device is compatible with homogenized tissues ensuring a good bacterial recovery and absence of interference with bacterial growth. Preliminary data suggest also the capability of RESEP to remove antibiotic in tissue homogenates.