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Background Information Gene Salmonella Resides Macrophages Role Salmonella Pathogenesis
Seebio Colanic acid polymer generated the rspA knockout strain and complement strain in S. Typhimurium 14028. Ex-vivo and in-vivo infectivity was looked at macrophage and epithelial cell lines and Caenorhabditis elegans (C. elegans). The mutant strain differentially formed the biofilm at different temperatures by altering the expression of genes involved in the synthesis of cellulose and curli. Besides, the mutant strain is hyperproliferative intracellularly and showed increased bacterial burden in C.

elegans. The mutant strain became more infectious and lethal, causing faster death of the worms than the wild type, and also modulates the worm's innate immunity. Thus, we found that the rspA deletion mutant was more pathogenic. In this study, we concluded that the rspA gene differentially regulates the biofilm formation in a temperature dependent manner by modulating the genes involved in the synthesis of cellulose and curli and negatively regulates the Salmonella virulence for longer persistence inside the host. Conflict of interest statement: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The authors have no conflict of interest to declare related to this article. Vidya Devi Negi reports financial provided by National Institute of Technology Rourkela. Vibrio cholerae O1 strain TSI-4 produces the exopolysaccharide materials that Vibrio cholerae O1 strain TSI-4 (El Tor, Ogawa) can shift to a rugose colony morphology from its normal translucent colony morphology in response to nutrient starvation.

We have investigated differences between the rugose and translucent forms of V. cholerae O1 strain TSI-4. Electron microscopic examination of the rugose form of TSI-4 (TSI-4/R) revealed thick, electron-dense exopolysaccharide materials surrounding polycationic ferritin-stained cells, while the ferritin-stained material was absent around the translucent form of TSI-4 and D-galactose (7:10:2:3). The expression of an amorphous exopolysaccharide promotes biofilm development under static culture conditions. Colanic acid compound by the rugose strain was determined by scanning electron microscopy, and most of the surface of the film was colonized by actively dividing rod cells. The corresponding rugose and translucent strains were compared for stress resistance. By having exopolysaccharide materials, the rugose strains acquired resistance to osmotic and oxidative stress.

Our data indicated that an exopolysaccharide material on the surface of the rugose strain promoted biofilm formation and resistance to the effects of two stressing Comparative proteomic analysis of biofilm and planktonic cells of Neisseria Neisseria meningitidis is a commensal of the human nasopharynx occasionally causing invasive disease. In vitro biofilms have been employed to model meningococcal carriage. A proteomic analysis of meningococcal biofilms was conducted and metabolic changes related to oxygen and nutrient limitation and upregulation of proteins involved in ROS defense were observed. The upregulated MntC which protects against ROS was shown to be required for meningococcal biofilm formation, but not for planktonic growth. ROS-induced proteomic changes might train the biofilm to cope with immune effectors. Clinical isolates of Acinetobacter baumannii from a Portuguese hospital: PFGE characterization, antibiotic susceptibility and biofilm-forming ability. Acinetobacter baumannii is an emerging pathogen associated with nosocomial infections that in addition has shown an increasing resistance to antibiotics.

In this work the genetic diversity of A. baumannii isolates from a Portuguese hospital, their antibiotic resistance profiles and ability to form biofilms was studied. Seventy-nine clinical A. baumannii isolates were characterized by pulsed-field gel electrophoresis (PFGE) with 9 different PFGE profiles being were resistant to 12 of the 17 tested antibiotics and classified as multidrug-resistant (MDR). In addition, 74% of the isolates showed biofilm formation ability, however no statistical significance with antibiotic resistance was observed. In contrast, urine samples isolates were more likely to form biofilms than strains isolated from other sources. Our findings highlight the high number of MDR A.

baumannii isolates and the importance of the formation of biofilms as a potential virulence factor. Effects of green tea compound epigallocatechin-3-gallate against Stenotrophomonas maltophilia infection and biofilm.
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