Evaluation of a serum-free transport medium supplemented with cyanobacterial extract, for the optimal survival of Helicobacter pylori from biopsy samples and strains.

The purpose of this work was to evaluate the use of an alternative transport medium supplemented with a cyanobacterial extract (CE), free of animal derivatives, to preserve the viability of Helicobacter pylori strains during long-term transportation and allow its recovery from biopsy samples. The transport media evaluated were Mueller-Hinton broth 0.3% agar (MH) and 0.3% of CE (MH-CE). MH broth 5% fetal calf serum (FCS) was used as the reference medium (MH-FCS). Biopsy samples from 134 patients, H. pylori NCTC 11638 and six clinical isolates were studied. A higher recovery (p ≤ 0.001) at 4°C was obtained in MH-CE than in MH-FCS after 96 h of storage. Only MH-CE allowed recovery after 120 h. The H. pylori recovery at room temperature after 96 h was higher (p ≤ 0.005) in MH-CE than in MH-FCS. Similar survival rates were observed in biopsy samples conserved in MH-CE and MH-FCS at 4°C. The recovery after 48 h at room temperature in MH-CE was higher (p ≤ 0.05) than MH-FCS and was the only medium allowing recovery after 72 h. The MH-CE medium is a simple, inexpensive and animal derivatives-free transport medium that can be used to preserve H. pylori viability and its recovery from biopsy samples.