Project description:Sepsis resulting from microbial colonization of the bloodstream is a serious health concern associated with high mortality rates. The objective of this study was to define the physiologic requirements of Citrobacter freundii in the bloodstream as a model for bacteremia caused by opportunistic Gram-negative pathogens. A genetic screen in a murine host identified 177 genes that contributed significantly to fitness, the majority of which were broadly classified as having metabolic or cellular maintenance functions. Among the pathways examined, the Tat protein secretion system conferred the single largest fitness contribution during competition infections and a putative Tat-secreted protein, SufI, was also identified as a fitness factor. Additional work was focused on identifying relevant metabolic pathways for bacteria in the bloodstream environment. Mutations that eliminated the use of glucose or mannitol as carbon sources in vitro resulted in loss of fitness in the murine model and similar results were obtained upon disruption of the cysteine biosynthetic pathway. Finally, the conservation of identified fitness factors was compared within a cohort of Citrobacter bloodstream isolates and between Citrobacter and Serratia marcescens, the results of which suggest the presence of conserved strategies for bacterial survival and replication in the bloodstream environment.
Project description:The ability of a bacterial population to survive in different niches, as well as in stressful and rapidly changing environmental conditions, depends greatly on its genetic content. To survive such fluctuating conditions, bacteria have evolved different mechanisms to modulate phenotypic variations and related strategies to produce high levels of genetic diversity. Laboratories working in microbiological diagnosis have shown that Citrobacter freundii is very versatile in its colony morphology, as well as in its biochemical, antigenic and pathogenic behaviours. This phenotypic versatility has made C. freundii difficult to identify and it is frequently confused with both Salmonella enterica and Escherichia coli. In order to determine the genomic events and to explain the mechanisms involved in this plasticity, six C. freundii isolates were selected from a phenotypic variation study. An I-CeuI genomic cleavage map was created and eight housekeeping genes, including 16S rRNA, were sequenced. In general, the results showed a range of both phenotypes and genotypes among the isolates with some revealing a greater similarity to C. freundii and some to S. enterica, while others were identified as phenotypic and genotypic intermediary states between the two species. The occurrence of these events in natural populations may have important implications for genomic diversification in bacterial evolution, especially when considering bacterial species boundaries. In addition, such events may have a profound impact on medical science in terms of treatment, course and outcomes of infectious diseases, evading the immune response, and understanding host-pathogen interactions.
Project description:Citrobacter freundii is an opportunistic pathogen responsible for many urinary tract infections acquired in hospitals and is thus a concern for public health. C. freundii phage Stevie might prove beneficial as a treatment against these infections. The complete genome of Stevie and its key features are described here.
Project description:Citrobacter braakii and Citrobacter freundii are Gram-negative opportunistic pathogens associated with many infectious diseases, including septicemia, in humans and animals. Here, we report the draft genome sequences of seven C. braakii strains and one C. freundii strain isolated from Canadian wastewater treatment facilities.
Project description:Citrobacter freundii is responsible for various opportunistic nosocomial infections. Phage therapies against C. freundii may prove useful in human medicine for treatment of infections caused by the ubiquitous bacteria. Here, we announce the complete genome sequence of the C. freundii Felix O1-like myophage Mijalis and present its features.
Project description:Bacteriophage Merlin is a T4-like myophage which infects Citrobacter freundii, a member of the Enterobacteriaceae family. C. freundii is an opportunistic pathogen that is a common cause of nosocomial infections. This report announces the complete genome of myophage Merlin and describes its features.
Project description:Citrobacter freundii is a Gram-negative opportunistic pathogen that causes dangerous infections such as neonatal meningitis. C. freundii also harbors antibiotic resistance, making phages infecting this host valuable tools. Here, we announce the complete genome of the C. freundii FelixO1-like myophage Michonne and describe its notable features.
Project description:As an opportunistic pathogen, Citrobacter freundii is involved in a wide spectrum of nosocomial infections. C. freundii phages may prove useful as therapeutics for treating infections caused by multidrug-resistant C. freundii strains. Here, we report the complete genome sequence of C. freundii siphophage Sazh, which is closely related to Enterobacteria phages T1 and TLS.
Project description:Citrobacter freundii is a Gram-negative opportunistic pathogen that is associated with urinary tract infections. Bacteriophages infecting C. freundii can be used as an effective treatment to fight these infections. Here, we announce the complete genome sequence of the C. freundii Felix O1-like myophage Mordin and describe its features.
Project description:Citrobacter freundii is a Gram-negative, opportunistic pathogen that can be fatal to newborns or immunocompromised patients. Bacteriophages against this bacterium can be useful for therapeutic purposes. Here, we describe the complete genome and the key features of the pseudo T-even C. freundii bacteriophage Miller.