Cronobacter Support
05-15-2009, 07:44 PM
1st International Conference on Cronobacter Poster Abstract 33
Heat adaptation improves the survival potential of Cronobacter spp. to heat stress, but not dry stress.
For the vast majority of the population, Cronobacter spp. (formally Enterobacter sakazakii) are of little significance. However, for a particularly vulnerable group of low birthweight and immunocompromised infants, this pathogen can cause a rare and potentially fatal illness with symptoms including neonatal meningitis, septicaemia and enterocolitis. The mortality rate is about 30 – 80%, and for those that survive the consequences are severe. Most bacteria have been shown to exhibit an adaptive response, where exposure to a mild stress confers resistance to severe stress either with the same or additional stressors. The survival of Cronobacter spp. at 52°C after an adaptive period of 30 min. at 46°C was investigated for milk and broth-grown cells. Adapted and unadapted cells were inoculated into dry powder and survival was monitored over time. The effect of reconstitution on Cronobacter spp. survival was also monitored. On adaptation, survival after 5 min. at 52°C of milk-grown cells was increased by about 1.5-log whereas survival of broth-grown cells was increased by about 3-log. While adaptation increased the survival potential of heat stress, it did not increase the survival potential in dry stress or during reconstitution of deliberately contaminated powder using microwave heating or conventional heating. Since adaptation increased the growth potential of Cronobacter spp. in the presence of the membrane active antibiotic ampicillin (but not in the presence of RNA polymerase/protein inhibitors rifampicin or tetracycline), it is likely that membrane changes during adaptation are responsible for the increased survival. Adaptation of Cronobacter spp. to heat does not increase the survival potential in powder or during reconstitution.
Benedict Arku1, Séamus Fanning2 and Kieran Jordan1
1Teagasc, Moorepark Food Research Centre, Fermoy, Cork, Ireland and 2Centre for Food Safety, UCD Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland.
Heat adaptation improves the survival potential of Cronobacter spp. to heat stress, but not dry stress.
For the vast majority of the population, Cronobacter spp. (formally Enterobacter sakazakii) are of little significance. However, for a particularly vulnerable group of low birthweight and immunocompromised infants, this pathogen can cause a rare and potentially fatal illness with symptoms including neonatal meningitis, septicaemia and enterocolitis. The mortality rate is about 30 – 80%, and for those that survive the consequences are severe. Most bacteria have been shown to exhibit an adaptive response, where exposure to a mild stress confers resistance to severe stress either with the same or additional stressors. The survival of Cronobacter spp. at 52°C after an adaptive period of 30 min. at 46°C was investigated for milk and broth-grown cells. Adapted and unadapted cells were inoculated into dry powder and survival was monitored over time. The effect of reconstitution on Cronobacter spp. survival was also monitored. On adaptation, survival after 5 min. at 52°C of milk-grown cells was increased by about 1.5-log whereas survival of broth-grown cells was increased by about 3-log. While adaptation increased the survival potential of heat stress, it did not increase the survival potential in dry stress or during reconstitution of deliberately contaminated powder using microwave heating or conventional heating. Since adaptation increased the growth potential of Cronobacter spp. in the presence of the membrane active antibiotic ampicillin (but not in the presence of RNA polymerase/protein inhibitors rifampicin or tetracycline), it is likely that membrane changes during adaptation are responsible for the increased survival. Adaptation of Cronobacter spp. to heat does not increase the survival potential in powder or during reconstitution.
Benedict Arku1, Séamus Fanning2 and Kieran Jordan1
1Teagasc, Moorepark Food Research Centre, Fermoy, Cork, Ireland and 2Centre for Food Safety, UCD Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland.