Tenacity of Enterococcus cecorum at different environmental conditions

Aims

Our aim was to analyse the survival of Enterococcus cecorum (EC) at various temperatures, relative air humidities and on different substrates commonly existing in broiler houses.

Methods and results

A pathogenic EC isolate (EC14) was used to inoculate sterile litter, polyvinyl chloride (PVC) and dust samples. Incubation at 37, 25 or 15°C with either 32% relative humidity (RH) or 78% RH followed. At defined time points (0-4272 h post-inoculation), samples were examined in triplicate for the total viable count. Selected combinations were repeated for a non-pathogenic and two additional pathogenic EC strains. For EC14, the measured survival time ranged from 48 to 4272 h (178 days) depending on the substrate-humidity-temperature combination. The longevity was the highest on litter, followed by dust and then PVC. Lower temperatures facilitated its survival, lower relative air humidity favoured the survival only in combination with 25 or 15°C. All three pathogenic strains showed longer survival times (up to 432 h, 18 days) compared to the non-pathogenic EC strain (168 h, 7 days) under the same conditions.

Conclusions

Enterococcus cecorum demonstrates a high persistence in the environment especially at 15°C and 32% RH.

Significance and impact of the study

Hygiene management plans should consider the durability of EC and the risk of a carry-over to control consecutive EC outbreaks.