Aerobic bacteria as Escherichia coli can survive in ESwabTM medium after a 3 month-freezing at -80°C but not after multiple thawing

Abstract

Pretesting of procedures for specimen conservation should be part of preliminary studies for trials especially when quantification of bacteria must be performed in a second time. Quantitative epidemiological studies of multidrug resistant organisms sampled from rectal swabs could be then particularly favored. The aim of this preliminary study, was to evaluate the performance of the flocked swab with liquefied Amies transport medium ESwab, for the survival evaluation of aerobic bacteria, from rectal swab sampling according to the number of freezing at -80{degrees}C and thawing cycles and the time of freezing. We first observed that quantification was not reliable after F/T cycles whereas a unique freezing could be performed especially when studying E. coli isolates. The second experiment allowed us to observe that this stability could be obtained until 3 month-freezing. Our study represents a preliminary study, confirming the utility of ESwab in microbiological diagnostics and research studies, not only for molecular bacterial tests, but also, for the maintenance of bacterial viability in clinical specimens.