This review discusses the state-of-the-art of research into biocorrosion and the biofouling of metals and alloys of industrial usage. The key concepts needed to understand the main effects of microorganisms on metal decay, and current trends in monitoring and control strategies to mitigate the deleterious effects of biocorrosion and biofouling are also described. Several relevant cases of biocorrosion studied by our research group are provided as examples: (i) biocorrosion of aluminum and its alloys by fungal contaminants of jet fuels; (ii) sulfate-reducing bacteria (SRB)-induced corrosion of steel; (iii) biocorrosion and biofouling interactions in the marine environment; (iv) monitoring strategies for assessing biocorrosion in industrial water systems; (v) microbial inhibition of corrosion; (vi) use and limitations of electrochemical techniques for evaluating biocorrosion effects. Future prospects in the field are described with respect to the potential of innovative techniques in microscopy (environmental scanning electron microscopy, confocal scanning laser microscopy, atomic force microscopy), new spectroscopic techniques for the study of corrosion products and biofilms (energy dispersion X-ray analysis, X-ray photoelectron spectroscopy, electron microprobe analysis) and electrochemistry (electrochemical impedance spectroscopy, electrochemical noise analysis).
Scientists study the world as it is; engineers create the world that has never beenTheodore von Kármán (1881–1963) The core tenet of synthetic biology is applying engineering principles such as standardization, modularity and rational design to accelerate the design-build-test loop aimed at reprogramming biological systems by endowing them with novel tasks (Endy, 2005). This circumstance has been broadly exploited to engineer whole-cell catalysts able to produce a plethora of added-value molecules (Lee et al., 2012; Nielsen and Keasling, 2016; de Lorenzo et al., 2018). Accordingly, the last few years have witnessed a steady increase in the number and type of molecules that can be accessed through rational modification of biocatalysts (Renata et al., 2015; Smanski et al., 2016; Arnold, 2018) – after all, and as recently pointed out by Prather (2019), biology is a most remarkable and versatile chemist. Yet, only a very limited number of structurally simple metabolites (e.g. the diols 1,4-butanediol and 1,3-propanediol) and a few natural active compounds (e.g. artemisinin) have found their way towards industrial-scale production (Calero and Nikel, 2019). Indeed, commercially relevant bioprocesses account for a mere 3.5% of the total production volume of commodity and specialty chemicals nowadays (Campbell et al., 2017). Accessing new-to-Nature products through synthetic microbiology is not only desirable, but also an actual necessity in a rapidly changing world in which the access to natural, fossil-based resources is becoming critically limited. The European chemical industry can definitely benefit from the purposeful redesign of the ‘biochemical palate’ of bacteria to access products that are difficult to obtain otherwise. Bringing non-biological chemical elements into the biochemical agenda of cell factories, e.g. halogens and silicon (O'Hagan and Deng, 2015; Kan et al., 2016), has the potential of actually revolutionizing bioproduction by multiplying the catalytic power of whole-cell biocatalysts. The biological incorporation of fluorine (F) into organic molecules is a particularly fascinating possibility to break the state-of-the-art in the chemical industry. Current technologies for addition of F into organic structures rely on chemical reactions derived from non-renewable sources, and often require corrosive reagents (Harsanyi and Sandford, 2015) – with the corresponding negative environmental impact that they cause. The expansion of the market of fluorinated molecules in the pharmaceutical [ca. 25% of the drugs currently licensed contain some type of fluorinated structure (Wang et al., 2014)], agriculture and material sectors worldwide (Fig. 1) is not matched by the development of more efficient, safer and milder technologies needed for their production. The global market demand of fluorochemicals is expected to reach >5300 kiloTons by 2024, expanding at a compound annual growth rate of 4.3% during the period 2014–2024. Because of the broad applications of fluoropolymers in essentially all industrial sectors, these fluorinated compounds represent >50% of the increase in the overall demand of fluorochemicals (Fig. 1). Indeed, the global fluoropolymer market was valued at 4700 M€ in 2015, and is expected to reach >7800 M€ by 2022, registering a compound annual growth rate of 7.7% from 2016 to 2022. The Asia–Pacific axis accounted for a >45% share of the total revenue of fluorochemicals in 2015, followed by North America and then Europe. Moreover, developing countries in the Asia–Pacific region are anticipated to register steady growth rates in their individual economies owing to the increasing growth of the overall, worldwide economy. What is the role of synthetic microbiology in tackling these issues, and positioning Europe as a leader region for innovation towards a true bioeconomy based in new-to-Nature products? As of today, there are no alternatives to traditional F chemistry available for production, and classical chemistry approaches have largely failed to provide an economically and environmentally sustainable route to fluorochemicals. Against this background, the EU project SinFonia (Synthetic biology-guided engineering of Pseudomonas putida for biofluorination), coordinated by P.I.N., brings together 13 partners [including 5 small-to-medium enterprises (SMEs) and a large multinational company] with the common goal of providing a bio-based solution for the production of fluorochemicals (Fig. 2). P. putida is the bacterial chassis of choice to engineer trans-metabolisms for the production of this sort of molecules (Nikel and de Lorenzo, 2018), which require a complex biochemistry that few (if any) bacteria can support. The scope of SinFonia, a Research and Innovation Action embedded in the BIOTEC-03-2018―Synthetic biology to expand diversity of nature's chemical production call, will set the stage for a future economically, ecologically and societally sustainable value chain for the production of novel, bio-based fluoropolymers from renewable substrates. In particular, the markets addressed in the domain of fluoropolymer applications are key for some of the most vital value chains for Europe competitiveness, i.e. electronics, automotive and textiles. Synthetic microbiology lays at the core technologies to be implemented in SinFonia to enable novel biochemistries in the platform strain KT2440. Meanwhile, what is the situation of biotechnology-based companies in Europe to broaden their scope through synthetic microbiology? As recently indicated by Vilanova and Porcar (2019), bio-based production keeps growing in number and revenues in the EU, and the market, traditionally controlled by a handful of big chemical and pharma companies, is expanding through the activities of SMEs that developed creative business models based on research and development as the pillar of competitiveness. UK and Germany form a powerful hub of biotechnology companies – in 2017, around 30% of all venture capital in Europe went to activities based in UK. Scandinavian countries are likewise strong promoters of innovation in the industrial sector. The so-called Medicon Valley is a leading international life sciences cluster in Europe, spanning the Greater Copenhagen region of eastern Denmark and southern Sweden and composed by a large number of life science companies and research institutions. Life science companies in Medicon Valley employed 41 300 individuals in 2015, registering an annual increase in this trend of around 4%. Denmark leads the way in biotechnology-oriented companies: in 2016, for instance, the Danish biotechnology sector was classified as the best in Europe, only behind United States and Singapore globally (Morrison and Lähteenmäki, 2017). Research and innovation in the Scandinavian region (and in Denmark in particular) is fuelled by >2000 M€ of tax contribution. Technology transfer is also an important part of the region-wide initiative: the number of patent applications submitted to the European Patent Office by Danish life science companies rose 16% between 2008 and 2016. Taken together, these figures indicate that the ground for novel, biotechnology-based (and synthetic biology-inspired) entrepreneur endeavours in the Scandinavian region is flourishing. EU-funded research and innovation actions, which bring together diverse academic expertise as well as technical and industrial known-how, will be major facilitators for the much sought academia-to-industry transition. The technology transfer to the industrial sector could take place in many ways, but there are mainly two models of value chain development of bio-based processes. The first model is absorption, where parts or all of the value chain of synthetic microbiology are used within a sector-specific company. This approach implies that an acquisition of facilities, human resources and knowledge is pursued by the company that is aiming to bring the new product(s) and/or process(es) to the market. This also implies either a profound organizational change (usually an extremely complex process in a company – the success of which cannot be taken for granted), or the acquisition of an entire new company (basically an SME). Selling-in, in contrast, does not require a transformational change: a product is designed in a company and sold into the production step of a specific sector. The challenge here is to properly address the question ‘what is to be sold and to whom’. The two strategies can be implemented depending on the dynamics of the market targeted – and, again, a fertile ground for the development of spin-offs and drop-in companies is a pre-requisite for the smooth transition of knowledge-based technologies into actual applications in the industrial sector. The adoption of one model or the other will have a profound influence on this rapidly growing field, shaping the value chain ecosystem that will emerge in the next 20–30 years. The ecosystems resulting from the different options are substantially different; in the first case (absorption), it will be the multinationals to lead the change, with spin-offs and start-ups providing the seeds of innovation without ever growing to a fully mature stage. In the second scenario (selling-in), it is more likely that a more diverse ecosystem will emerge, sustaining new companies to grow to a mature stage. Currently in Europe, the pharmaceutical industry has shown preference for the absorption model, while the chemical industry is still waiting to see the first large batch of bio-based commodities to be developed – and which of the options will be preferred in this case is still a matter of debate. Considering the lessons learnt from the first wave of synthetic biology-related products and the public debate associated, it is likely that a mixed scenario will emerge, and this would be also be preferable and more sustainable in the long run. One way or the other, some long-sought goals for sustainable bio-based production of chemical building blocks are expected to be attained in the near future. Synthetic microbiology will not only underpin these developments, but it will also become increasingly pervasive throughout the full spectrum of research and development of new-to-Nature, added-value molecules – tackling some issues that have been almost neglected in the field, such scaling up of synthetic biology constructs and processes (de Lorenzo and Couto, 2019). Combined with the creation of jobs and enterprises, synthetic microbiology holds the promise to decisively contribute to the much-wanted shift from a petrochemical-based to a bio-based society and economy in Europe. Wide public acceptance will be essential in this respect; at the same time, a diverse ecosystem supported by a dynamic community of both SMEs and large companies is more likely to sustain European competitiveness. Considering the critical point of public acceptance of disruptive technologies and science innovation, and in the particular case of synthetic microbiology, lessons can be learnt from the past, when we saw how agricultural biotechnology had met reluctance or rejection among the public. With the new technologies brought about by synthetic biology, the question many people ask themselves is whether history will repeat itself, i.e. whether there will be public controversy when the resulting products start to be commercialized (Torgersen, 2009). The commitment of the scientific community to divulge a correct and effective communication on the matter is vital in this sense. For such innovations to boost European industry competitiveness at the current stage of development, it will be essential to pursue the debate on (i) what a synthetic (micro)biology actually is, (ii) where does its value come from, (iii) what is to be sold and to whom (i.e. future value chains) and (iv) the standardization of such products (ensuring market reproducibility of the new product). Such a case-by-case debate should be started already at very low TRLs (technology readiness levels) and should include a coherent policy for the protection of knowledge (Chiarotti, Portaluri and Martinelli, unpublished data). From a broader perspective, the impact on synthetic (micro)biology on the future of jobs in Europe is an important topic that raises many interesting questions, e.g. will this new wave create new and qualified jobs?, or how existing job profiles will be affected? This kind of reasoning is strictly interlinked with both the model of adoption of synthetic biology products by the industry and the impact that such products will have on the market. Some job profiles might disappear, some might require substantial re-learning, some others will be new, including completely different skills and background knowledge. The extent and speed of this transformation is a function of business adoption, government and education – and thus a function of human decisions (Gulbranson, 2018). The scenario we have drafted implicitly considers technology development as a social process, over which many different factors play a key role. The outcome can only be forecasted by taking into consideration an integrated and wider perspective, e.g. the Research Responsible Innovation (Owen et al., 2013). Emerging in the last decade, this approach dares to take into account the difficult dilemma between thinking and reasoning on the future trajectories that an innovation can take, how to control it, and the need to allow enough freedom of movement for an innovation to unfold. Far from trying to impose limitations, we believe that considering a perspective of inclusiveness, anticipation and responsiveness to the possible impacts of synthetic microbiology by the relevant stakeholders could effectively contribute to its success as a socially positive transformation and value creation at the same time. In fact, all the scenarios discussed in this article lead to an emerging picture in EU, where the advances in synthetic (micro)biology approaches to chemistry is paired with a likewise impactful growth in the creation of new enterprises (or new activities in established enterprises) and the creation of employment – building into an authentic circular, bio-based economy. The financial support from The Novo Nordisk Foundation (NNF10CC1016517) and from the European Union's Horizon2020 Research and Innovation Programme under grant agreement No. 814418 (SinFonia) to P.I.N. is gratefully acknowledged. The responsibility of this article lies with the authors. The NNF and the European Union are not responsible for any use that may be made of the information contained therein. The authors have no conflict of interest to declare.
Recent recommendations for biology education highlight the role of authentic research experiences early in undergraduate education as a means of increasing the number and quality of biology majors. These experiences will inform students on the nature of science, increase their confidence in doing science, as well as foster critical thinking skills, an area that has been lacking despite it being one of the desired outcomes at undergraduate institutions and with future employers. With these things in mind, we have developed an introductory biology laboratory course where students design and execute an authentic microbiology research project. Students in this course are assimilated into the community of researchers by engaging in scholarly activities such as participating in inquiry, reading scientific literature, and communicating findings in written and oral formats. After three iterations of a semester-long laboratory course, we found that students who took the course showed a significant increase in their understanding of the nature of authentic research and their level of critical thinking skills.
The critical nature of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician and the microbiologists who provide enormous value to the health care team. This document, developed by experts in both adult and pediatric laboratory and clinical medicine, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. Sections are divided into anatomic systems, including Bloodstream Infections and Infections of the Cardiovascular System, Central Nervous System Infections, Ocular Infections, Soft Tissue Infections of the Head and Neck, Upper Respiratory Infections, Lower Respiratory Tract infections, Infections of the Gastrointestinal Tract, Intraabdominal Infections, Bone and Joint Infections, Urinary Tract Infections, Genital Infections, and Skin and Soft Tissue Infections; or into etiologic agent groups, including arboviral Infections, Viral Syndromes, and Blood and Tissue Parasite Infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. In addition, the pediatric needs of specimen management are also addressed. There is redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a reference to guide physicians in choosing tests that will aid them to diagnose infectious diseases in their patients.
The multidisciplinary nature of food microbiology is one of the things that make it so fascinating as a career. Food microbiologists must understand basic microbiology, the roles of beneficial microbes, food safety regulations and policy, and the proper practices that ensure safe and healthy food for billions of people. They must also be nimble thinkers, willing to embrace new analytical methods, eager to solve problems, and ever vigilant about keeping the food supply safe. The fourth edition of Food Microbiology: An Introduction is designed for undergraduate courses in food science, nutrition, and microbiology. This edition has been substantially updated with new information on topics like the Food Safety Modernization Act and the use of bacteriophage as antimicrobial agents, while retaining the pedagogy that students and professors appreciate. Written in a clear and easy-to-understand style, the textbook is divided into four sections: Basics of food microbiology presents the growth processes of food microorganisms, the biology of spores and sporeformers, and the establishment of microbiological criteria in food safety programs, and it introduces students to some of the methods used to detect and enumerate microbes in food and food handling equipment. Foodborne pathogenic bacteria opens with a discussion about the regulatory agencies and surveillance systems responsible for keeping the United States food supply safe. The remainder of the section is a rogue's gallery of pathogenic bacteria found in food. Other microbes important in food examines the many beneficial and detrimental ways that microorganisms affect our food supply. The section opens with a look at numerous foods, like beer, bread, pickles, and cheeses, created by the fermentation reactions of lactic acid bacteria and yeast. The rest of the section looks at microbes that are less desirable: the spoilers of food, toxigenic molds, and foodborne parasites. This section closes with a look at viruses and prions. Control of microorganisms in food discusses the tactics used to inhibit microbial growth in food. The section ends with a chapter on the essentials of developing quality sanitation and HACCP programs in food processing facilities.
Applied and Environmental Microbiology (AEM) publishes descriptions of all aspects of applied microbial research, basic research on microbial ecology, and research of a genetic and molecular nature that focuses on microbial topics of practical value. Research must address salient microbiological principles, fundamental microbial processes, or basic questions in applied or environmental microbiology. Topics that are considered include microbiology in relation to foods, agriculture, industry, biotechnology, public health, plants, and invertebrates and basic biological properties of bacteria, fungi, algae, protozoa, and other simple eukaryotic organisms as related to microbial ecology. Manuscripts should report new and significant findings that advance the understanding of microbiology and upon which other scientists may build.
Thirteen years after the first bacterial genome was sequenced, Rino Rappuoli, Stanley Falkow and colleagues review what has changed in microbiology research as a consequence of genomics and address the implications of the genomic era for the future of microbiology. Genomics has revolutionized every aspect of microbiology. Now, 13 years after the first bacterial genome was sequenced, it is important to pause and consider what has changed in microbiology research as a consequence of genomics. In this article, we review the evolving field of bacterial typing and the genomic technologies that enable comparative analysis of multiple genomes and the metagenomes of complex microbial environments, and address the implications of the genomic era for the future of microbiology.
暂无摘要（点击查看原文获取完整内容）
The quantitative deep-tissue microbiology of the infected feet of 32 patients with diabetes mellitus was studied, and the clinical features of the patients were analyzed. Techniques of specimen collection designed to avoid contamination from surface flora were used to study amputated lower limbs. Cultures of deep tissue from six patients yielded only aerobes, and for one patient, only anaerobes. Cultures for 25 patients yielded a mixture of aerobes and anaerobes. A mean of 4.81 species (2.84 aerobes and 1.97 anaerobes) were isolated from each patient. The density of growth of anaerobes, however, was significantly higher than that of aerobes. Culture specimens obtained by curettage of the base of the ulcer correlated better with results of deep-tissue culture than did those obtained by needle aspiration or swab of the ulcers. The most frequently isolated organisms were Bacteroides species, anaerobic streptococci, group D streptococci, Clostridium species, and Proteus species. The presence of anaerobes was associated with a higher frequency of fever and foul-smelling lesions and with the presence of a foot ulcer. Prior antibiotic therapy did not appear to influence the nature of the microorganisms isolated. The polymicrobial nature of this disease should be considered when antimicrobial therapy is indicated.
The prevalence of multidrug-resistant microbial pathogens due to the continued misuse and overuse of antibiotics in agriculture and medicine is raising the prospect of a return to the preantibiotic days of medicine at the time of diminishing numbers of drug leads. The good news is that an increased understanding of the nature and extent of microbial diversity in natural habitats coupled with the application of new technologies in microbiology and chemistry is opening up new strategies in the search for new specialized products with therapeutic properties. This review explores the premise that harsh environmental conditions in extreme biomes, notably in deserts, permafrost soils and deep-sea sediments select for micro-organisms, especially actinobacteria, cyanobacteria and fungi, with the potential to synthesize new druggable molecules. There is evidence over the past decade that micro-organisms adapted to life in extreme habitats are a rich source of new specialized metabolites. Extreme habitats by their very nature tend to be fragile hence there is a need to conserve those known to be hot-spots of novel gifted micro-organisms needed to drive drug discovery campaigns and innovative biotechnology. This review also provides an overview of microbial-derived molecules and their biological activities focusing on the period from 2010 until 2018, over this time 186 novel structures were isolated from 129 representatives of microbial taxa recovered from extreme habitats.
The critical nature of the microbiology laboratory in infectious disease diagnosis calls for a close, positive working relationship between the physician/advanced practice provider and the microbiologists who provide enormous value to the healthcare team. This document, developed by experts in laboratory and adult and pediatric clinical medicine, provides information on which tests are valuable and in which contexts, and on tests that add little or no value for diagnostic decisions. This document presents a system-based approach rather than specimen-based approach, and includes bloodstream and cardiovascular system infections, central nervous system infections, ocular infections, soft tissue infections of the head and neck, upper and lower respiratory infections, infections of the gastrointestinal tract, intra-abdominal infections, bone and joint infections, urinary tract infections, genital infections, and other skin and soft tissue infections; or into etiologic agent groups, including arthropod-borne infections, viral syndromes, and blood and tissue parasite infections. Each section contains introductory concepts, a summary of key points, and detailed tables that list suspected agents; the most reliable tests to order; the samples (and volumes) to collect in order of preference; specimen transport devices, procedures, times, and temperatures; and detailed notes on specific issues regarding the test methods, such as when tests are likely to require a specialized laboratory or have prolonged turnaround times. In addition, the pediatric needs of specimen management are also emphasized. There is intentional redundancy among the tables and sections, as many agents and assay choices overlap. The document is intended to serve as a guidance for physicians in choosing tests that will aid them to quickly and accurately diagnose infectious diseases in their patients.
Whole genome sequencing (WGS) promises to be transformative for the practice of clinical microbiology, and the rapidly falling cost and turnaround time mean that this will become a viable technology in diagnostic and reference laboratories in the near future. The objective of this article is to consider at a very practical level where, in the context of a modern diagnostic microbiology laboratory, WGS might be costeffective compared to current alternatives. We propose that molecular epidemiology performed for surveillance and outbreak investigation and genotypic antimicrobial susceptibility testing for microbes that are difficult to grow represent the most immediate areas for application of WGS, and discuss the technical and infrastructure requirements for this to be implemented.
Until recently, microbial identification in clinical diagnostic laboratories has mainly relied on conventional phenotypic and gene sequencing identification techniques. The development of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) devices has revolutionized the routine identification of microorganisms in clinical microbiology laboratories by introducing an easy, rapid, high throughput, low-cost, and efficient identification technique. This technology has been adapted to the constraint of clinical diagnostic laboratories and has the potential to replace and/or complement conventional identification techniques for both bacterial and fungal strains. Using standardized procedures, the resolution of MALDI-TOF MS allows accurate identification at the species level of most Gram-positive and Gram-negative bacterial strains with the exception of a few difficult strains that require more attention and further development of the method. Similarly, the routine identification by MALDI-TOF MS of yeast isolates is reliable and much quicker than conventional techniques. Recent studies have shown that MALDI-TOF MS has also the potential to accurately identify filamentous fungi and dermatophytes, providing that specific standardized procedures are established for these microorganisms. Moreover, MALDI-TOF MS has been used successfully for microbial typing and identification at the subspecies level, demonstrating that this technology is a potential efficient tool for epidemiological studies and for taxonomical classification.
Preface Acknowledgments Part I: The Nature of Infection Section 1. Key Issues in Hospital Medicine Section 2. Patient Safety Section 3. Quality Improvement Section 4. Leadership and Practice Management Skills Section 5. Professionalism and Medical Ethics Section 6. Medical Legal Issues and Risk Management Section 7. Teaching and Development Part II: Medical Consultation and Co-Management Section 1. Core Tenets of Medical Consultation Section 2. Key Issues Relating to Surgery Section 3. Anesthesia Section 4. Perioperative Assessment and Management Section 5. Perioperative Antithrombotic Management and Prevention Section 6. Medical Management of Neurosurgical Patients Section 7. Medical Management of Orthopedic Surgery Patients Section 8. Bariatric Surgery Part III: Clinical Problem-Solving in Hospital Medicine Part IV: Approach to the Patient at the Bedside Part V: Hospitalist Skills Section 1. Interpretation of Common Tests Section 2. Optimizing Utilization of Radiology Services Section 3. Procedures Part VI: Clinical Conditions Section 1. Emergency Medicine Section 2. Cardiovascular Medicine Section 3. Critical Care Section 4. Dermatology Section 5. Endocrinology Section 6. Gastroenterology Section 7. Geriatrics Section 8. Hematology Section 9. Oncology Section 10. Infectious Diseases Section 11. Neurology Section 12. Palliative Care Section 13. Pregnancy Section 14. Psychiatry Section 15. Addiction Section 16. Pulmonary and Allergy Immonology Section 17. Renal Section 18. Rheumatology Section 19. Vascular Medicine Section 20. Wartime Medicine Index
In a world where most emerging and reemerging infectious diseases are zoonotic in nature and our contacts with both domestic and wild animals abound, there is growing awareness of the potential for human acquisition of animal diseases. Like other Pasteurellaceae, Pasteurella species are highly prevalent among animal populations, where they are often found as part of the normal microbiota of the oral, nasopharyngeal, and upper respiratory tracts. Many Pasteurella species are opportunistic pathogens that can cause endemic disease and are associated increasingly with epizootic outbreaks. Zoonotic transmission to humans usually occurs through animal bites or contact with nasal secretions, with P. multocida being the most prevalent isolate observed in human infections. Here we review recent comparative genomics and molecular pathogenesis studies that have advanced our understanding of the multiple virulence mechanisms employed by Pasteurella species to establish acute and chronic infections. We also summarize efforts being explored to enhance our ability to rapidly and accurately identify and distinguish among clinical isolates and to control pasteurellosis by improved development of new vaccines and treatment regimens.
The phyllosphere represents the habitat provided by the aboveground parts of plants, and on a global scale supports a large and complex microbial community. Microbial interactions in the phyllosphere can affect the fitness of plants in natural communities, the productivity of agricultural crops, and the safety of horticultural produce for human consumption. The structure of phyllosphere communities reflects immigration, survival and growth of microbial colonists, which is influenced by numerous environmental factors in addition to leaf physico-chemical properties. The recent use of culture-independent techniques has demonstrated considerable previously unrecognized diversity in phyllosphere bacterial communities. Furthermore, there is significant recent evidence that plant genotype can play a major role in determining the structure of phyllosphere microbial communities. The main aims of this review are: (i) to discuss the diversity of phyllosphere microbial populations; (ii) to consider the processes by which microbes colonize the phyllosphere; (iii) to address the leaf characteristics and environmental factors that determine the survival and growth of colonists; (iv) to discuss microbial adaptations that allow establishment in the phyllosphere habitat and (v) to evaluate evidence for plant genotypic control of phyllosphere communities. Finally, we suggest approaches and priority areas for future research on phyllosphere microbiology.
SUMMARY: The human gingival niche is a unique microbial habitat. In this habitat, biofilm organisms exist in harmony, attached to either enamel or cemental surfaces of the tooth as well as to the crevicular epithelium, subjacent to a rich vascular plexus underneath. Due to this extraordinary anatomical juxtaposition, plaque biofilm bacteria have a ready portal of ingress into the systemic circulation in both health and disease. Yet the frequency, magnitude, and etiology of bacteremias due to oral origin and the consequent end organ infections are not clear and have not recently been evaluated. In this comprehensive review, we address the available literature on triggering events, incidence, and diversity of odontogenic bacteremias. The nature of the infective agents and end organ infections (other than endocarditis) is also described, with an emphasis on the challenge of establishing the link between odontogenic infections and related systemic, focal infections.