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Category: Bacterial Pathogenesis
Biofilms and Device-Related Infections, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555818104/9781555811594_Chap22-1.gif /docserver/preview/fulltext/10.1128/9781555818104/9781555811594_Chap22-2.gifAbstract:
The study of bacterial biofilms is more advanced in the engineering field than in the medical field, but the simple realization that biofilms are involved in chronic infections opens the way for a massive transfer of valuable information from the engineering realm to the medical realm and for its application to the treatment of infectious diseases. Pseudomonas aeruginosa first came to the attention of biofilm microbiologists because it predominates in cold alpine streams and grows predominantly (99.99%) in biofilms in this natural habitat. The Center for Biofilm Engineering (CBE) has established the fact that most biofilms assume this microcolony and water channel structure, including all biofilms formed by the few grampositive species examined to date, and the most significant consequence of this new observation is that we must now explain how these elaborate structures are established and maintained. If we try to imagine the bacterial survival strategies that would have been effective in the earliest stages of the development of life on this planet, growth in stationary biofilms that were protected from unfavorable conditions would prevent bacteria from being swept into acid or boiling downstream pools and from surges of threatening water from upstream sources. The role of host defenses in controlling biofilm infections is discussed in the chapter. There is a growing conviction that antibiotics are losing their ability to control bacterial infections because the bacteria have mobilized all of their survival strategies in the face of this frontal attack.
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Diagrammatic representation of the cellular structure of a microbial biofilm showing the directly ovserved shapes of matrix-enclosed microcolonies and intervening water channels, in which convective flow occurs.
Diagrammatic representation of the cellular structure of a microbial biofilm showing the directly ovserved shapes of matrix-enclosed microcolonies and intervening water channels, in which convective flow occurs.
Isobar map of dissolved oxygen concentration as measured directly in a living biofilm by the use of a microeclectrode, showing that the centers of microcolonies can be essentially anoxic, even when the biofilm is growing in ambient air.
Isobar map of dissolved oxygen concentration as measured directly in a living biofilm by the use of a microeclectrode, showing that the centers of microcolonies can be essentially anoxic, even when the biofilm is growing in ambient air.
Polycrylamide gel electrophoresis gel showing the pattern of production of OMP's by cells of P. aeruginosa in the biofilm mode of growth (lane 5) versus production by cells in the planktonic mode of growth (lanes 1 to 4 and 6). The differences in OMP production between these cells indicate that the biofilm phenotype differs profoundly from the planktonic phenotype (H. Yu and J. W. Costerton, unpublished data)
Polycrylamide gel electrophoresis gel showing the pattern of production of OMP's by cells of P. aeruginosa in the biofilm mode of growth (lane 5) versus production by cells in the planktonic mode of growth (lanes 1 to 4 and 6). The differences in OMP production between these cells indicate that the biofilm phenotype differs profoundly from the planktonic phenotype (H. Yu and J. W. Costerton, unpublished data)
Scanning electron micrograph of an S. aureus biofilm on an endocardial pacemaker lead, showing spherical bacterial cells embedded in dehydration-condensed matrix material. These biofilm cells were resistant to a 6-week course of very high-dose antibiotic therapy.
Scanning electron micrograph of an S. aureus biofilm on an endocardial pacemaker lead, showing spherical bacterial cells embedded in dehydration-condensed matrix material. These biofilm cells were resistant to a 6-week course of very high-dose antibiotic therapy.
Scanning electron micrograph of a mixed-species bacterial biofilm on the copper component of a Copper 7 IUD worn by an asymptomatic patient.
Scanning electron micrograph of a mixed-species bacterial biofilm on the copper component of a Copper 7 IUD worn by an asymptomatic patient.
Transmission electron micrograph of a matrix-enclosed microcolony of cells P. aeruginosa in the lung of a rat with a model infection designed to mimic cystic fibrosis in human patients. Note the dehydration-related shrinkage of the matrix material and the dark “crust” of immune complex material surrounding the microcolony.
Transmission electron micrograph of a matrix-enclosed microcolony of cells P. aeruginosa in the lung of a rat with a model infection designed to mimic cystic fibrosis in human patients. Note the dehydration-related shrinkage of the matrix material and the dark “crust” of immune complex material surrounding the microcolony.
Confocal scanning laser micrograph of a silver-coated sewing cuff fabric designed for a mechanical heart valve. This thread had been exposed to cells of S. epidermidis, which had colonized its surface to produce matrix-enclosed microcolonies containing living (green) and a few dead (orange and red) cells in a developing biofilm.
Confocal scanning laser micrograph of a silver-coated sewing cuff fabric designed for a mechanical heart valve. This thread had been exposed to cells of S. epidermidis, which had colonized its surface to produce matrix-enclosed microcolonies containing living (green) and a few dead (orange and red) cells in a developing biofilm.
Partial list of human infections involving biofilms a
Partial list of human infections involving biofilms a