Biofilms and public health Choisy, Claude
Bulletin de l'Académie nationale de médecine,
2011 Apr-May, 20110401, Volume:
195, Issue:
4-5
Journal Article
Peer reviewed
Micro-organisms do not always exist in planctonic forms (single cells or small groups). To survive, especially in limiting media, they may adhere to inert or living surfaces. This enables them to ...multiply within a community protected by an extracellular matrix, thus forming a biofilm which protects them from antimicrobials. Biofilms have many potential consequences for public health. Some are positive, such as the commensal biofilms that protect against pathogenic bacteria, while environmental biofilms may be a source of outbreaks of respiratory or gastrointestinal diseases or infections associated with implanted medical devices. Respiratory tract infection can be caused by aerosols of fragmented biofilms growing in warm humid conditions (air cooling towers, hot springs, showers, etc.). Digestive tract infection can arise from biofilms formed during food manufacturing or packaging processes. Colonized implanted medical devices can lead to sepsis. This article examines the role of central venous catheters, taking into account the surgical site. In vivo studies show that the source of catheter infection may be exogenous or endogenous, while in vitro studies of biofilms show that ablation of the device is the best solution. Prevention is difficult, as biofilm formation is multifactorial. Physical and biological knowledge of biofilms may help to limit their formation and growth.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Fourier-transform infrared spectroscopy was used to explore structural changes in bacteria under different incubation conditions. In particular, differences between
Bradyrhizobium japonicum (BRJ) ...grown in liquid and on solid media were investigated, as well as the rearrangement of BRJ after transfer from one medium to the other. The FT-IR absorption bands located between 1200 and 900 cm
−1 region, vary in spectral shape and intensity when BRJ were suspended in solution medium or plated on solid medium. In agreement with the electronic micrograph data, these spectroscopic changes are due to the changes involving the bacterial wall (peptidoglycan) when BRJ are plated in agar medium. By means of this FT-IR ultrastructural study of
Bradyrhizobium japonicum bacteria, it has been possible to follow and to evaluate the rate of the molecular change in bacteria without any destructive interference. This indicates that FT-IR spectroscopy can prove to be a valuable technique in the monitoring of metabolic events in bacterial cells relevant to agriculture as well as environmental and health sciences.
Choisy Claude. Le botaniste de Damas : Lafleuriel-Zakri (Simone), La Botaniste de Damas (roman), 2010. In: Revue d'histoire de la pharmacie, 99e année, N. 375, 2012. pp. 398-399.
Fourier-transform infrared spectroscopy was used to examine bacterial characteristic structural differences under different incubation conditions (media). The data obtained with bacteria grown in ...liquid medium then plated on solid medium agree with those previously obtained using other techniques: increase in sugar level inside (reserve) and/or around the bacteria (slime). In particular, it was found that the transition from solid to liquid medium immediately induced the decrease of this sugar level. Whereas in the transition from liquid to solid medium, sugar level increase was slower to occur.
Membrane-bound proteinase 3 (PR3m) is the main target antigen of anti-neutrophil cytoplasmic autoantibodies (ANCA) in granulomatosis with polyangiitis, a systemic small-vessel vasculitis. Binding of ...ANCA to PR3m triggers neutrophil activation with the secretion of enzymatically active PR3 and related neutrophil serine proteases, thereby contributing to vascular damage. PR3 and related proteases are activated from pro-forms by the lysosomal cysteine protease cathepsin C (CatC) during neutrophil maturation. We hypothesized that pharmacological inhibition of CatC provides an effective measure to reduce PR3m and therefore has implications as a novel therapeutic approach in granulomatosis with polyangiitis. We first studied neutrophilic PR3 from 24 patients with Papillon–Lefèvre syndrome (PLS), a genetic form of CatC deficiency. PLS neutrophil lysates showed a largely reduced but still detectable (0.5–4%) PR3 activity when compared with healthy control cells. Despite extremely low levels of cellular PR3, the amount of constitutive PR3m expressed on the surface of quiescent neutrophils and the typical bimodal membrane distribution pattern were similar to what was observed in healthy neutrophils. However, following cell activation, there was no significant increase in the total amount of PR3m on PLS neutrophils, whereas the total amount of PR3m on healthy neutrophils was significantly increased. We then explored the effect of pharmacological CatC inhibition on PR3 stability in normal neutrophils using a potent cell-permeable CatC inhibitor and a CD34+ hematopoietic stem cell model. Human CD34+ hematopoietic stem cells were treated with the inhibitor during neutrophil differentiation over 10 days. We observed strong reductions in PR3m, cellular PR3 protein, and proteolytic PR3 activity, whereas neutrophil differentiation was not compromised.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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Cathepsin C (CatC) is a tetrameric cysteine dipeptidyl aminopeptidase that plays a key role in activation of pro-inflammatory serine protease zymogens by removal of a N-terminal ...pro-dipeptide sequence. Loss of function mutations in the CatC gene is associated with lack of immune cell serine protease activities and cause Papillon-Lefèvre syndrome (PLS). Also, only very low levels of elastase-like protease zymogens are detected by proteome analysis of neutrophils from PLS patients. Thus, CatC inhibitors represent new alternatives for the treatment of neutrophil protease-driven inflammatory or autoimmune diseases. We aimed to experimentally inactivate and lower neutrophil elastase-like proteases by pharmacological blocking of CatC-dependent maturation in cell-based assays and in vivo. Isolated, immature bone marrow cells from healthy donors pulse-chased in the presence of a new cell permeable cyclopropyl nitrile CatC inhibitor almost totally lack elastase. We confirmed the elimination of neutrophil elastase-like proteases by prolonged inhibition of CatC in a non-human primate. We also showed that neutrophils lacking elastase-like protease activities were still recruited to inflammatory sites. These preclinical results demonstrate that the disappearance of neutrophil elastase-like proteases as observed in PLS patients can be achieved by pharmacological inhibition of bone marrow CatC. Such a transitory inhibition of CatC might thus help to rebalance the protease load during chronic inflammatory diseases, which opens new perspectives for therapeutic applications in humans.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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