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Bacterial Proliferation (bacterial + proliferation)

Distribution by Scientific Domains

Medical Sciences	60%

Selected Abstracts

Cholestatic liver disease: pathophysiology and therapeutic options

LIVER INTERNATIONAL, Issue 2002
AF. Hofmann
Abstract: Cholestasis results from defective canalicular secretion of bile or obstruction to bile flow distal to the canaliculus. In early primary biliary cirrhosis, bile secretion continues, because of the secretory pressure of bile or because some ductules are not obstructed. With complete cholestasis, a bile acid deficiency occurs in the small intestinal lumen leading to lipid maldigestion and fat-soluble vitamin malabsorption. Bacterial proliferation, bacterial translocation to lymph nodes and endotoxemia may also occur leading to an acute phase reaction. Retention of bile acids in the hepatocyte leads to apoptosis. Accumulation of bile acids in the systemic circulation leads to pruritus, and may contribute to endothelial injury in the lungs and kidney. Early attempts to mimic hepatic excretory function by hemoperfusion over adsorbent columns were unsuccessful for a variety of reasons. Extracorporeal dialysis against albumin offers promise of a realistic albeit partial simulation of hepatic excretory function. [source]

Visible light-induced killing of bacteria as a function of wavelength: Implication for wound healing

LASERS IN SURGERY AND MEDICINE, Issue 6 2010
Anat Lipovsky MSc
Abstract Background and objective Visible light (400,800,nm) at high intensity was previously found to kill bacteria that are frequently found in infected wounds, while low-power white light enhances bacterial proliferation. The phototoxic effect was found to involve induction of reactive oxygen species (ROS) production by the bacteria. The aim of the present study was to identify the most effective wavelengths in the visible range for inducing a bactericidal effect. Experimental ROS production in Staphylococcus aureus and Escherichia coli as a function of wavelengths in the visible range (400,500, 500,800, 415, and 455,nm) was studied using the electron paramagnetic resonance (EPR) spin trapping technique. The phototoxicity of 415 and 455,nm light at different fluencies on the survival of S. aureus and E. coli was assessed by colony count of the bacteria following irradiation. Results ROS production following blue (400,500,nm) light illumination was found to be higher than that of red (500,800,nm). Within the blue range, light of 415,nm induced more ROS than 455,nm, which correlated with results obtained for the reduction in colony count of S. aureus and E. coli following illumination using equal intensities of these two wavelengths. At low fluencies, both 415 and 455,nm enhanced proliferation of S. aureus but reduced viability of E. coli. Conclusion Intense blue light, preferably at 415,nm, could be used for bacterial eradication. However, it should be noted that low intensity of visible light can be dangerous since it may promote proliferation of the microorganisms. Lasers Surg. Med. 42:467,472, 2010. © 2010 Wiley,Liss, Inc. [source]

Dynamics of growth and dissemination of Salmonella in vivo

CELLULAR MICROBIOLOGY, Issue 10 2010
Kathryn G. Watson
Summary The last decade has witnessed increasing research on dissemination of bacterial pathogens in their hosts and on the processes that underlie bacterial spread and growth during organ colonization. Here, we discuss work on the mouse model of human typhoid fever caused by Salmonella enterica serovar Typhimurium. This has revealed the use of several routes of systemic dissemination that result in colonization and growth within the spleen and liver, the major sites of bacterial proliferation. We also highlight techniques that enable in vivo analysis of the infecting population at the spatiotemporal and single cell levels. These approaches have provided more detailed insights into the events underlying the dynamics of Salmonella replication, spread and clearance within host organs and tissues. [source]

Modulation of caspases and their non-apoptotic functions by Legionella pneumophila

CELLULAR MICROBIOLOGY, Issue 2 2010
Amal O. Amer
Summary Legionella pneumophila has become a model system to decipher the non-apoptotic functions of caspases and their role in immunity. In permissive cells, the L. pneumophila -containing vacuole evades endosomal traffic and is remodelled by the endoplasmic reticulum. Evasion of the endosomes is mediated by the Dot/Icm type IV secretion system. Upon L. pneumophila infection of genetically restrictive cells such as wild-type (WT) C57Bl/6J murine macrophages, flagellin is sensed by the NOD-like receptor Nlrc4 leading to caspase-1 activation by the inflammasome complex. Then, caspase-7 is activated downstream of the Nlrc4 inflammasome, promoting non-apoptotic functions such as L. pneumophila -containing phagosome maturation and bacterial degradation. Interestingly, caspase-3 is activated in permissive cells during early stages of infection. However, caspase-3 activation does not lead to apoptosis until late stages of infection because it is associated with potent Dot/Icm-mediated anti-apoptotic stimuli that render the infected cells resistant to external apoptotic inducers. Therefore, the role of caspase-1 and non-apoptotic functions of executioner caspases are temporally and spatially modulated during infection by L. pneumophila, which determine permissiveness to intracellular bacterial proliferation. This review will examine the novel activation pathways of caspases by L. pneumophila and discuss their role in genetic restriction and permissiveness to infection. [source]

Significance of human ,-defensins in the epithelial lining fluid of patients with chronic lower respiratory tract infections

CLINICAL MICROBIOLOGY AND INFECTION, Issue 1 2007
S. Yanagi
Abstract Human ,-defensins (hBDs) are the most abundant antimicrobial peptides in epithelial cells, and function in the host immune system. Respiratory epithelial cells express hBDs to inhibit bacterial proliferation during respiratory tract infections. The aim of this study was to investigate the release of hBDs into the respiratory tract and their benefit as a host defence system in chronic Pseudomonas aeruginosa infections. The levels of four hBD peptides (hBD-1,hBD-4) were measured in the bronchial epithelial lining fluid (ELF) of nine patients with chronic lower respiratory tract infection caused by P. aeruginosa. Eight patients with idiopathic pulmonary fibrosis and eight volunteers free of pulmonary disease were recruited as controls. ELF was obtained by bronchoscopic microsampling and hBD levels were measured by radioimmunoassays. The antimicrobial effects of hBDs were studied individually and in combination using an in-vitro colony count assay for P. aeruginosa. Concentrations of hBD-1 and hBD-3 tended to be higher in patients with chronic lower respiratory tract infection than in the controls. hBD-2 and hBD-4 were detected in ELF from five and four of nine patients, respectively, but the hBD levels in controls were all below the limits of detection. All patients with infection caused by mucoid P. aeruginosa had detectable hBD-2 and hBD-4 levels in ELF. In-vitro colony count assays showed a potential synergism between hBD-2 and hBD-4 in inhibiting bacterial proliferation. The findings indicate that hBDs, especially hBD-2 and hBD-4, are pathophysiologically important in infections caused by mucoid strains of P. aeruginosa. [source]