Contribution of the thermotolerance genomic island to increased thermal tolerance in Cronobacter strains
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Cronobacter spp. are opportunistic pathogens associated with serious infections in neonates. Increased stress tolerance, including the thermotolerance of some Cronobacter strains, can promote their survival in production facilities and thus raise the possibility of contamination of dried infant formula which has been identified as a potential source of infection. Some Cronobacter strains contain a genomic island, which might be responsible for increased thermotolerance. By analysis of Cronobacter sequenced genomes this determinant was found to be present in only 49/73 Cronobacter sakazakii strains and in 9/14 Cronobacter malonaticus strains. The island was also found in 16/17 clinical isolates originating from two hospitals. Two configurations of the locus were detected; the first one with the size of 18 kbp containing the thrB-Q genes and a shorter version (6 kbp) harbouring only the thrBCD and thrOP genes. Strains containing the thermotolerance island survived significantly better at 58 °C comparing to a C. sakazakii isogenic mutant lacking the island and strains with the longer version of the island were 2–10 times more tolerant than those with the shortened sequence. The function of the genomic island was further confirmed by its cloning into a low-copy vector and transforming it into the isogenic mutant. Different levels of rpoS, encoding for stress-response sigma factor, expression were also associated with variability in strain thermotolerance.
KeywordsCronobacter spp. Heat stress rpoS Thermotolerance Thermotolerance island
This publication is the result of the project implementation (ITMS 26240220086) supported by the Research & Development Operational Programme funded by the ERDF and by Slovak Ministry of Education under the Contract No. VEGA 1/0709/12. Project supported by Research Support Foundation, Vaduz - Grant project No. 801100021/39 - Surveillance of Infectious Complications in Hemato-Oncological Patients.
- Alsonosi A, Hariri S, Kajsik M, Orieskova M, Hanulik V, Roderova M, Petrzelova J, Kollarova H, Drahovska H, Forsythe S, Holy O (2015) The speciation and genotyping of Cronobacter isolates from hospitalised patients. Eur J Clin Microbiol Infect Dis 34:1979–1988PubMedCentralCrossRefPubMedGoogle Scholar
- Caubilla-Barron J, Forsythe S (2007) Dry stress and survival time of Enterobacter sakazakii and other Enterobacteriaceae in dehydrated powdered infant formula. J Food Prot 70:2111–2117Google Scholar
- Caubilla-Barron J, Hurrell E, Townsend S, Cheetham P, Loc-Carrillo C, Fayet O, Prere MF, Forsythe SJ (2007) Genotypic and phenotypic analysis of Enterobacter sakazakii strains from an outbreak resulting in fatalities in a neonatal intensive care unit in France. J Clin Microbiol 45:3979–3985PubMedCentralCrossRefPubMedGoogle Scholar
- Iversen C, Lehner A, Mullane N, Bidlas E, Cleenwerck I, Marugg J, Fanning S, Stephan R, Joosten H (2007) The taxonomy of Enterobacter sakazakii: proposal of a new genus Cronobacter gen. nov. and descriptions of Cronobacter sakazakii comb. nov. Cronobacter sakazakii subsp. sakazakii, comb. nov., Cronobacter sakazakii subsp. malonaticus subsp. nov., Cronobacter turicensis sp. nov., Cronobacter muytjensii sp. nov., Cronobacter dublinensis sp. nov. and Cronobacter genomospecies 1. BMC Evol Biol 7:64PubMedCentralCrossRefPubMedGoogle Scholar
- Iversen C, Mullane N, McCardell B, Tall BD, Lehner A, Fanning S, Stephan R, Joosten H (2008) Cronobacter gen. nov., a new genus to accommodate the biogroups of Enterobacter sakazakii, and proposal of Cronobacter sakazakii gen. nov., comb. nov., Cronobacter malonaticus sp. nov., Cronobacter turicensis sp. nov., Cronobacter muytjensii sp. nov., Cronobacter dublinensis sp. nov., Cronobacter genomospecies 1, and of three subspecies, Cronobacter dublinensis subsp. dublinensis subsp. nov., Cronobacter dublinensis subsp. lausannensis subsp. nov. and Cronobacter dublinensis subsp. lactaridi subsp. nov. Int J Syst Evol Microbiol 58:1442–1447CrossRefPubMedGoogle Scholar
- Joseph S, Cetinkaya E, Drahovska H, Levican A, Figueras MJ, Forsythe SJ (2012a) Cronobacter condimenti sp. nov., isolated from spiced meat, and Cronobacter universalis sp. nov., a species designation for Cronobacter sp. genomospecies 1, recovered from a leg infection, water and food ingredients. Int J Syst Evol Microbiol 62:1277–1283CrossRefPubMedGoogle Scholar
- Joseph S, Desai P, Ji Y, Cummings CA, Shih R, Degoricija L, Rico A, Brzoska P, Hamby SE, Masood N, Hariri S, Sonbol H, Chuzhanova N, McClelland M, Furtado MR, Forsythe SJ (2012b) Comparative analysis of genome sequences covering the seven Cronobacter species. PLoS ONE 7:e49455PubMedCentralCrossRefPubMedGoogle Scholar
- Orieskova M, Gajdosova J, Oslanecova L, Ondreickova K, Kaclikova E, Stuchlik S, Turna J, Drahovska H (2013) Function of thermotolerance genomic island in increased stress resistance of Cronobacter sakazakii. J Food Nutr Res 52:37–44Google Scholar
- Stephan R, Grim CJ, Gopinath GR, Mammel MK, Sathyamoorthy V, Trach LH, Chase HR, Fanning S, Tall BD (2014) Re-examination of the taxonomic status of Enterobacter helveticus, Enterobacter pulveris and Enterobacter turicensis as members of the genus Cronobacter and their reclassification in the genera Franconibacter gen. nov. and Siccibacter gen. nov. as Franconibacter helveticus comb. nov., Franconibacter pulveris comb. nov. and Siccibacter turicensis comb. nov., respectively. Int J Syst Evol Microbiol 64:3402–3410PubMedCentralCrossRefPubMedGoogle Scholar