Analysis of the DNA region mediating increased thermotolerance at 58°C in Cronobacter sp. and other enterobacterial strains
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Cronobacter spp. are opportunistic pathogens associated with serious infections in neonates. The increased stress tolerance, including thermoresistance, of some Cronobacter strains can promote their survival in production facilities and thus raise the possibility of contamination of dried infant milk formula, which has been identified as a potential source of infection. In this study, we characterized a DNA region which is present in some Cronobacter strains and which contributes to their prolonged survival at 58°C. The 18 kbp long region containing 22 open reading frames was sequenced in Cronobacter sakazakii ATCC 29544. The major feature of the region contained a cluster of conserved genes, most of them having significant homologies with bacterial proteins involved in some type of stress response, including heat, oxidation and acid stress. The same thermoresistance DNA region was detected in strains belonging to the genera Cronobacter, Enterobacter, Citrobacter and Escherichia and its presence positively correlated with increased thermotolerance.
KeywordsCronobacter Enterobacter sakazakii Heat resistance Food
This publication is the result of the project implementation: Centre of excellence for utilization of information bio-macromolecules in disease prevention and in improving of quality of life (ITMS 26240120027) supported by the Research & Development Operational Programme funded by the ERDF. This work was also supported by Slovak Research and Development Agency under the contract No. APVV-27-009705 and by Slovak Ministry of Education under the contract No. VEGA 1/0344/10. Tomáš Kuchta and Katarína Oravcová from the Food Research Institute Bratislava are acknowledged for the critical reading of the manuscript.
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