Bacterial Persistence and Biofilms - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Bacterial Persistence and Biofilms write by Phillip Richard Palmer. This book was released on 2022. Bacterial Persistence and Biofilms available in PDF, EPUB and Kindle. Bacterial persistence is a transient state of dormancy exhibited by a small subset of cells that allow them to survive antibiotic treatment. This is a ubiquitous phenomenon exhibited by all bacteria to all known classes of antibiotics which can result in chronic and relapsing infections. Persister cells are bacteria that are metabolically tolerant, not genetically resistant to antibiotics. However, because they confer survival in the presence of antibiotics, they pose a risk of developing resistance. Antibiotic resistance is currently a world-wide problem as resistant infections are becoming more numerous and the discovery rate of novel antibiotics is decreasing. Biofilms contain increased levels of persisters due to the nutrient limiting conditions in the interior of the biofilm due to limiting diffusion rates through the dense extracellular polymeric matrix. The specific mechanisms that lead to persistence are redundant making them difficult to overcome pharmacologically. Stress responses are thought to push the cell towards a dormant state in response to either accidental damage from cellular processes, or to antibiotics. Toxin-antitoxin systems have been shown to increase levels of persister cells increasing the lag time after inoculation from overnight cultures. Persisters are difficult to study because they appear at such low frequencies in metabolically heterogenous populations. Experimenters are thus forced to choose between scale and resolution as single-cell experiments fail to observe sufficient numbers of cells. Many labs utilize methods of enriching for persisters, though the largest problem is that persisters cannot be identified except by surviving antibiotic treatments. This thesis discusses novel methods that can be used to study persistence and chronic bacterial infection. Recent advances in CRISPR biotechnology have created a large toolbox of molecular techniques. CRISPR-Cas9 is best known for creating gene knockouts with ease, but an enzymatically inactivated Cas9 has been developed and repurposed as a tool for gene knockdown. The gene target can be customized by modifying the CRISPR gRNA that is responsible for targeting the Cas9 to a gene by base-pair complementarity. This technology was validated in our lab by confirming knockdown of lacZ expression with blue-white selection. A detailed method for creating gRNA was reproduced from the original paper. Novel gRNAs were designed and cloned into the CRISPRi system to target the stringent response genes relA and spoT. These genes control the levels of the alarmone (p)ppGpp in the cell which when in abundance downregulates genes associated with growth and division and upregulates genes associated with survival. Targeting these genes with CRISPRi was explored as a mechanism of decreasing persistence to antibiotics in preliminary experiments. A top-down analysis was also used to investigate genes associated with chronic infections in nontypeable Haemophilus influenzae (NTHi). A large NTHi genomic dataset containing the whole genome sequences for thousands of clinical isolates, for which clinical metadata are available, is a valuable asset of our lab. Recently, Facebook published a machine learning model for classifying protein variants that had been trained one 250,000,000 proteins. We applied this model to all unique protein sequences in our NTHI genomic collection. These data were used to examine each gene for clusters of variants that correlated with the clinical metadata. A pipeline was developed to assess the strength of correlation with categories including health state, infection type, and patient age. Top hits were identified from significant hits with particular interest in clusters containing a single category of metadata (e.g., only sick isolates).
Bacterial Persistence
Bacterial Persistence - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Bacterial Persistence write by Jan Michiels. This book was released on 2015-10-15. Bacterial Persistence available in PDF, EPUB and Kindle. This volume presents a comprehensive collection of methods that have been instrumental to the current understanding of bacterial persisters. Chapters in the book cover topics ranging from general methods for measuring persister levels in Escherichia coli cultures, protocols for the determination of the persister subpopulation in Candida albicans, quantitative measurements of Type I and Type II persisters using ScanLag, to in vitro and in vivo models for the study of the intracellular activity of antibiotics. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Bacterial Persistence: Methods and Protocols brings together the most respected researchers in bacterial persistence whose studies will remain vital to understanding this field for many years to come.
Bacterial Biofilms
Bacterial Biofilms - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Bacterial Biofilms write by Tony Romeo. This book was released on 2008-02-26. Bacterial Biofilms available in PDF, EPUB and Kindle. Throughout the biological world, bacteria thrive predominantly in surface-attached, matrix-enclosed, multicellular communities or biofilms, as opposed to isolated planktonic cells. This choice of lifestyle is not trivial, as it involves major shifts in the use of genetic information and cellular energy, and has profound consequences for bacterial physiology and survival. Growth within a biofilm can thwart immune function and antibiotic therapy and thereby complicate the treatment of infectious diseases, especially chronic and foreign device-associated infections. Modern studies of many important biofilms have advanced well beyond the descriptive stage, and have begun to provide molecular details of the structural, biochemical, and genetic processes that drive biofilm formation and its dispersion. There is much diversity in the details of biofilm development among various species, but there are also commonalities. In most species, environmental and nutritional conditions greatly influence biofilm development. Similar kinds of adhesive molecules often promote biofilm formation in diverse species. Signaling and regulatory processes that drive biofilm development are often conserved, especially among related bacteria. Knowledge of such processes holds great promise for efforts to control biofilm growth and combat biofilm-associated infections. This volume focuses on the biology of biofilms that affect human disease, although it is by no means comprehensive. It opens with chapters that provide the reader with current perspectives on biofilm development, physiology, environmental, and regulatory effects, the role of quorum sensing, and resistance/phenotypic persistence to antimicrobial agents during biofilm growth.
Persister Cells and Infectious Disease
Persister Cells and Infectious Disease - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Persister Cells and Infectious Disease write by Kim Lewis. This book was released on 2019-11-13. Persister Cells and Infectious Disease available in PDF, EPUB and Kindle. This volume is a collection of chapters from the leading experts in the relatively new and burgeoning field of persister cell studies. Persisters play a leading role in the recalcitrance of chronic infections, and enable the development of classical antibiotic resistance. The focus of the book is on studies that provide an understanding of the mechanisms of persister formation, antibiotic tolerance and role in disease, at the molecular level.
Biofilm Infections
Biofilm Infections - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Biofilm Infections write by Thomas Bjarnsholt. This book was released on 2014-10-11. Biofilm Infections available in PDF, EPUB and Kindle. This book will cover both the evidence for biofilms in many chronic bacterial infections as well as the problems facing these infections such as diagnostics and treatment regimes. A still increasing interest and emphasis on the sessile bacterial lifestyle biofilms has been seen since it was realized that that less than 0.1% of the total microbial biomass lives in the planktonic mode of growth. The term was coined in 1978 by Costerton et al. who defined the term biofilm for the first time.In 1993 the American Society for Microbiology (ASM) recognised that the biofilmmode of growth was relevant to microbiology. Lately many articles have been published on the clinical implications of bacterial biofilms. Both original articles and reviews concerning the biofilm problem are available.
