Citrobacter Freundii Bacteria Research Articles

The application of ultrafiltration for separation of glycerol solution fermented by bacteria

Abstract A biotechnological synthesis generated a fermentation broth containing the dissociated forms of organic compounds and residual mineral salts. An effective method of selective removal of the ionic species and organic compounds from solutions comprises nanofiltration and reverse osmosis. Ultrafiltration (UF) was used in this work as a pre-treatment method for the preparation of feed for these processes. The UF study was carried out with a real broth, which was obtained using Citrobacter freundii bacteria for the fermentation of glycerol solutions, resulting in the UF permeate with turbidity below 0.1 NTU. However, a significant decline of the permeate flux was observed during the UF process. The influence of the transmembrane pressure on the fouling intensity of used ceramic membranes was investigated. A periodical membrane cleaning was carried out by rinsing with water and a 1 wt % solution of sodium hydroxide. The applied cleaning procedures permitted to restore the initial permeate flux.

Morphological alterations on Citrobacter freundii bacteria induced by erythrosine dye and laser light

The effect of the laser irradiation (532 nm) on films prepared from Citrobacter freundii mixed with erythrosine dye was investigated by using atomic force microscopy. It was observed that morphological changes of bacterial surfaces after irradiations, which were attributed to cellular damage of the outer membranes, are a result of a photodynamic effect. The results suggested that the combination of erythrosine and laser light at 532 nm could be a candidate to a photodynamic therapy against C. freundii.

Gene expression profiling in the skin of zebrafish infected with Citrobacter freundii

Skin is considered the largest immunologically active organ, but its molecular mechanism remains unclear in fish. Here, Affymetrix Zebrafish GeneChip was used to assess gene expression in the skin of zebrafish ( Danio rerio) infected with the bacterium Citrobacter freundii. The results showed that 229 genes were differentially expressed, of which 196 genes were upregulated and 33 genes were downregulated. Gene Ontology and KEGG pathway analyses indicated 88 genes significantly associated with skin immunity involved in complement activation and acute phase response, defense and immune response, response to stress and stimulus, antigen processing and presentation, cell adhesion and migration, platelet activation and coagulation factors, regulation of autophagy and apoptosis. When compared with transcriptional profiles of previously reported carp ( Cyprinus carpio) skin, a similar innate immunity (e.g., interferon, lectin, heat shock proteins, complements), and several different acute phase proteins (transferrin, ceruloplasmin, vitellogenin and alpha-1-microglobulin, etc.) were detected in zebrafish skin. The validity of the microarray results was verified by quantitative real-time PCR analysis of nine representative genes. This is first report that skin play important roles in innate immune responses to bacterial infection, which contribute to understanding the defense mechanisms of the skin in fish.

Citrobacter freundii cause of the disease of rainbow trout (Ncorhynchus Mykiss Wallbaum) in Serbia

In this paper we have demonstrated and described disease affecting one-year-old rainbow trout characterized with gastroenteritis and progressive mortality rate, indicating no typical bacteriological septicemical infection. Gastroenteritis of rainbow trout was isolated with Gramm mobile bacteria Citrobacter freundii. Citrobacter freundii cultures were identified by investigation of key phenotypic traits and biochemical methods - Api 20E system. Pathohistological investigation determined inflammatory changes on intestines. By artificial infection with pure Citrobacter freundii culture we have reproduced this disease. This was the first finding of Citrobacter freundii as inducer of disease affecting rainbow trout in Serbia.

Citrobacter freundii as a cause of disease in fish

The paper describes an illness of one-year rainbow trout fry that was characterized by gastroenteritis and progressively high mortality, but which did not indicate a typical bacterial infection; and a clinical illness of cyprinids that indicated typical acute bacterial septicemia caused by Gram-negative bacteria. These diseases of rainbow trout and cyprinids were caused by the Gram-negative motile bacterium Citrobacter freundii. Cultures of Citrobacter freundii were isolated and identified on the basis of key phenotypic characters and with the aid of the Api 20 E system. Pathohistological examination confirmed inflammatory changes in the intestine of rainbow trout; and inflammatory and necrotic changes in the internal organs of cyprinids. We were able to reproduce the illness by means of artificial infection with a pure culture of Citrobacter freundii. This is the first published report confirming Citrobacter freundii as a cause of fish disease in Serbia.

Sistemic Citrobacter Freundii infection in carp

The paper describes ta clinical disease in carp fish species which indicated a typical acute bacterial septicemia caused by the gram-negative bacteria Citrobacter freundii. An unusual mortality of carp fish species was observed during low water temperatures at the beginning of the year. A total of 39 samples were taken for laboratory examinations from diseased fish which had become darker, with expressed exophthalmus bleedings on the skin and eyes and 10 samples from clinically healthy fish. Part of the altered organs gills, parenchymatous organs and intestines were used for isolating the causes. The usal methods of bacteriological examinations were used for the investigations. Cultures were identified by examining key phenotype markings and using an Api 20E system as Citrobacter freundii. Other parts of parenchymatous organs and intestines were fixed in 10% formaline prepared according to the standard histological method. Pathohistological examinations established inflammatory and necrotic changes in internal organs. We succeeded in reproducing the disease with an artificial infection using a pure culture of Citrobacter freundii. This is the first published report on establishing Citrobacter freundii as the cause of carp diseases in Serbia.