Cronobacter Support
05-19-2009, 03:06 PM
1st International Conference on Cronobacter Poster Abstract 43
Genetic analysis of biofilm formation in Cronobacter sakazakii
Cronobacter spp. are opportunistic foodborne pathogens that can cause severe disease such as meningitis, sepsis and necrotizing enterocolitis in neonates. Mortality is high, and survivors often suffer irreversible brain damage. In a number of outbreaks, the most likely source of infection was found to be powdered infant formula. The organisms’ desiccation resistance and ability to form biofilms on different surfaces could contribute to their survival in formula powder and persistence in the hospital and production environment. So far, nothing is known about the genetic basis of biofilm formation and little about typical biofilm structure in these organisms. To genetically investigate biofilm development of Cronobacter spp., a random transposon mutant library of strain C. sakazakii ES5 was screened for altered biofilm formation. Identified mutations affected genes involved in flagellum structure and biogenesis, cellulose biosynthesis, c-d-GMP-signalling and basic cellular processes. Furthermore, a considerable proportion of identified mutations were located in poorly or uncharacterized genes. Interestingly, mutations were found in two uncharacterized genes localized next to each other in the genome. These mutants display a distinctive phenotype on congo red agar, which could indicate a role of this locus in extracellular matrix composition or regulation. Additionally, biofilm architecture was characterized by growing wildtype and mutant biofilms in a flow chamber system and subsequent investigation by CLSM. A model of Gram-negative biofilm formation developed in Pseudomonas aeruginosa seems to also largely apply to C. sakazakii biofilms. However, the number of uncharacterized genes found in this study illustrates that many questions remain to be answered.
Isabel Hartmann1, Paula Carranza2, Roger Stephan1, Kathrin Riedel2 and Angelika Lehner1
1 Institute for Food Safety and Hygiene, University of Zürich, Winterthurerstrasse 272, 8057 Zürich, Switzerland, 2 Department of Microbiology, Institute of Plant Biology, University of Zürich, 8057 Zürich, Switzerland.
Genetic analysis of biofilm formation in Cronobacter sakazakii
Cronobacter spp. are opportunistic foodborne pathogens that can cause severe disease such as meningitis, sepsis and necrotizing enterocolitis in neonates. Mortality is high, and survivors often suffer irreversible brain damage. In a number of outbreaks, the most likely source of infection was found to be powdered infant formula. The organisms’ desiccation resistance and ability to form biofilms on different surfaces could contribute to their survival in formula powder and persistence in the hospital and production environment. So far, nothing is known about the genetic basis of biofilm formation and little about typical biofilm structure in these organisms. To genetically investigate biofilm development of Cronobacter spp., a random transposon mutant library of strain C. sakazakii ES5 was screened for altered biofilm formation. Identified mutations affected genes involved in flagellum structure and biogenesis, cellulose biosynthesis, c-d-GMP-signalling and basic cellular processes. Furthermore, a considerable proportion of identified mutations were located in poorly or uncharacterized genes. Interestingly, mutations were found in two uncharacterized genes localized next to each other in the genome. These mutants display a distinctive phenotype on congo red agar, which could indicate a role of this locus in extracellular matrix composition or regulation. Additionally, biofilm architecture was characterized by growing wildtype and mutant biofilms in a flow chamber system and subsequent investigation by CLSM. A model of Gram-negative biofilm formation developed in Pseudomonas aeruginosa seems to also largely apply to C. sakazakii biofilms. However, the number of uncharacterized genes found in this study illustrates that many questions remain to be answered.
Isabel Hartmann1, Paula Carranza2, Roger Stephan1, Kathrin Riedel2 and Angelika Lehner1
1 Institute for Food Safety and Hygiene, University of Zürich, Winterthurerstrasse 272, 8057 Zürich, Switzerland, 2 Department of Microbiology, Institute of Plant Biology, University of Zürich, 8057 Zürich, Switzerland.