Antonie van Leeuwenhoek

, Volume 109, Issue 3, pp 405–414

Contribution of the thermotolerance genomic island to increased thermal tolerance in Cronobacter strains

  • Maria Orieskova
  • Michal Kajsik
  • Tomas Szemes
  • Ondrej Holy
  • Stephen Forsythe
  • Jan Turna
  • Hana Drahovska
Original Paper

Abstract

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.

Keywords

Cronobacter spp. Heat stress rpoThermotolerance Thermotolerance island 

Supplementary material

10482_2016_645_MOESM1_ESM.docx (101 kb)
Supplementary material 1 (DOCX 100 kb)

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Maria Orieskova
    • 1
  • Michal Kajsik
    • 1
  • Tomas Szemes
    • 1
  • Ondrej Holy
    • 2
  • Stephen Forsythe
    • 3
  • Jan Turna
    • 1
  • Hana Drahovska
    • 1
  1. 1.Department of Molecular Biology, Faculty of Natural SciencesComenius UniversityBratislavaSlovak Republic
  2. 2.Department of Preventive Medicine, Faculty of Medicine and DentistryPalacký University, OlomoucOlomoucCzech Republic
  3. 3.Pathogen Research Group, School of Science and TechnologyNottingham Trent UniversityNottinghamUK

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