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Respiratory Medicine Apr 2018Bacterial pathogens are the most frequent cause of pneumonia after transplantation. Early after transplantation, recipients are at higher risk for nosocomial infections.... (Review)
Review
Bacterial pathogens are the most frequent cause of pneumonia after transplantation. Early after transplantation, recipients are at higher risk for nosocomial infections. The most commonly encountered pathogens during this period are gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa …), but gram-positive coccus such as Staphylococcus aureus or Streptococcus pneumoniae and anaerobic bacteria can also be found. Empirical antibiotic therapy should be guided by previous colonisation of the recipient and bacterial resistance pattern in the hospital. Six months after transplantation, pneumonias are mostly due to community-acquired bacteria (S. pneumonia, H. influenza, Mycoplasma, Chlamydia and others). Opportunistic pathogens take advantage of the state of immunosuppression which is usually highest from one to six months after transplantation. During this period, but also occurring many years later in the setting of a chronically depressed immune system, bacterial pathogens with low intrinsic virulence can cause pneumonia. The diagnosis of pneumonia caused by opportunistic pathogens can be challenging. The delay in diagnosis preventing the early instauration of adequate treatment in kidney transplant recipients with a depressed immune system, frequently coupled with co-morbid conditions and a state of frailty, will affect prognosis and outcome, increasing morbidity and mortality. This review will focus on the most common opportunistic bacterial pathogens causing pneumonia in kidney transplant recipients: Legionella, Nocardia, Mycobacterium tuberculosis/nontuberculous, and Rhodococcus. Recognition of their specificities in the setting of immunosuppression will allow early diagnosis, crucial for initiation of effective therapy and successful outcome. Interactions with immunosuppressive therapy should be considered as well as reducing immunosuppression if necessary.
Topics: Aged; Anti-Bacterial Agents; Bacteria; Cross Infection; Humans; Immunosuppression Therapy; Kidney Transplantation; Legionella; Male; Middle Aged; Mycobacterium; Nocardia; Opportunistic Infections; Pneumonia, Bacterial; Prognosis; Rhodococcus; Transplant Recipients
PubMed: 29605219
DOI: 10.1016/j.rmed.2018.02.022 -
Oxidative Medicine and Cellular... 2022Infected wound is one of the most common and serious problem in wound management. Cold atmospheric plasma (CAP) is considered to have a good effect in wound healing as a...
Infected wound is one of the most common and serious problem in wound management. Cold atmospheric plasma (CAP) is considered to have a good effect in wound healing as a new type medicine. However, there is a key issue that has not been addressed in the treatment of infected wounds by plasma. Bacteria are always found in the deep region of the wound. When plasma is used to treat wounds, it also acts on normal tissue cells while decontaminating. What is the difference between the same dose of plasma acting on bacteria and normal cells? In this study, the most common bacteria (S. aureus, P. aeruginosa, and E. coli) in infected wound and two kinds of normal skin cells (human keratinocyte and human skin fibroblasts (HSF)) were selected to study the difference of the effects of the same dose of plasma on bacteria and cells. The results reveal that three kinds of 10 CFU mL bacteria could be effectively inactivated by 5 order after plasma treatment 3 min, and P. aeruginosa was more sensitive to plasma (could be inactivated 5 order after 2 min treatment). The 10 mL keratinocyte and HSF were treated with the same dose of plasma; keratinocyte can maintain over 90% of the activity and HSF cells can maintain over 70% of the activity. Moreover, the level of collagen I secreted by HSF increased. Therefore, cells can remain a high activity when a plasma dose capable of inactivating bacteria is applied to them.
Topics: Humans; Staphylococcus aureus; Escherichia coli; Wound Infection; Wound Healing; Plasma Gases; Pseudomonas aeruginosa
PubMed: 36506937
DOI: 10.1155/2022/1838202 -
Current Biology : CB Oct 2020The human nasal passages host a distinct community of microbes. Katherine P. Lemon describes this distinct community, and why it matters so much for human health.
The human nasal passages host a distinct community of microbes. Katherine P. Lemon describes this distinct community, and why it matters so much for human health.
Topics: Bacteria; Bacterial Infections; Humans; Microbiota; Nasal Cavity
PubMed: 33022252
DOI: 10.1016/j.cub.2020.08.010 -
Applied and Environmental Microbiology Jan 2013Animal guts and plant roots have absorption roles for nutrient uptake and converge in harboring large, complex, and dynamic groups of microbes that participate in... (Comparative Study)
Comparative Study Review
Animal guts and plant roots have absorption roles for nutrient uptake and converge in harboring large, complex, and dynamic groups of microbes that participate in degradation or modification of nutrients and other substances. Gut and root bacteria regulate host gene expression, provide metabolic capabilities, essential nutrients, and protection against pathogens, and seem to share evolutionary trends.
Topics: Animals; Bacteria; Biota; Gastrointestinal Tract; Plant Roots
PubMed: 23104406
DOI: 10.1128/AEM.02553-12 -
Nature Reviews. Microbiology May 2018Lipid research represents a frontier for microbiology, as showcased by hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse... (Review)
Review
Lipid research represents a frontier for microbiology, as showcased by hopanoid lipids. Hopanoids, which resemble sterols and are found in the membranes of diverse bacteria, have left an extensive molecular fossil record. They were first discovered by petroleum geologists. Today, hopanoid-producing bacteria remain abundant in various ecosystems, such as the rhizosphere. Recently, great progress has been made in our understanding of hopanoid biosynthesis, facilitated in part by technical advances in lipid identification and quantification. A variety of genetically tractable, hopanoid-producing bacteria have been cultured, and tools to manipulate hopanoid biosynthesis and detect hopanoids are improving. However, we still have much to learn regarding how hopanoid production is regulated, how hopanoids act biophysically and biochemically, and how their production affects bacterial interactions with other organisms, such as plants. The study of hopanoids thus offers rich opportunities for discovery.
Topics: Bacteria; Cell Membrane; Lipid Metabolism; Lipids; Plants
PubMed: 29456243
DOI: 10.1038/nrmicro.2017.173 -
The Journal of Investigative Dermatology Jul 1976
Review
Topics: Animals; Bacteria; Ecology; Hair; Humans; Skin; Staphylococcus aureus; Streptococcus pyogenes
PubMed: 778287
DOI: 10.1111/1523-1747.ep12513007 -
Journal of Dairy Science Aug 1996With the development of strictly anaerobic techniques and habitat-simulating media, a variety of bacteria were isolated from the rumen in the 1940s and 1950s. Based on... (Review)
Review
With the development of strictly anaerobic techniques and habitat-simulating media, a variety of bacteria were isolated from the rumen in the 1940s and 1950s. Based on standard morphological and physiological characteristics, the microbial ecosystem of the rumen contains a very complex population of bacteria. In recent years, ruminal bacteria have been re-evaluated with newer, more objective, and genetically valid methods of classification. Ribosomes are complicated structures, and their DNA-encoding sequences are relatively free from selective pressure. Because ribosomes have evolved slowly, they provide a long-term natural history of evolution. The invariable and hypervariable regions of rRNA genes can be used to group bacteria into kingdoms, genera, and species. The 16S rRNA sequences have provided a basis for renaming some ruminal species (Bacteroides amylophilus is now Ruminobacter amylophilus and Bacteroides succinogenes is now Fibrobacter succinogenes) and for classifying at least one recently isolated ruminal bacterium (e.g., Clostridium aminophilum). The DNA:DNA hybridization is a more sensitive method of assessing bacterial relatedness than is 16S rRNA. Bacterial strains within a species should have a high degree of DNA:DNA homology, but some species of ruminal bacteria (e.g., Prevotella ruminicola and Butyrivibrio fibrisolvens) had highly unrelated strains. Studies of 16S rRNA and DNA:DNA hybridization indicate that the diversity of ruminal bacteria has been greatly underestimated. Traditional studies of phylogeny of ruminal bacteria were stymied by the fastidious growth requirements of many ruminal bacteria, and enumeration was tedious and inaccurate. Modern methods of bacterial classification do not require in vitro culture and have the potential of detecting even a single cell.
Topics: Animal Nutritional Physiological Phenomena; Animals; Bacteria; DNA, Bacterial; Polymorphism, Restriction Fragment Length; RNA, Bacterial; Rumen
PubMed: 8880472
DOI: 10.3168/jds.S0022-0302(96)76506-2 -
Cell Chemical Biology Jan 2016Recent studies have illuminated a remarkable diversity and abundance of microbes living on and within the human body. While we are beginning to appreciate associations... (Review)
Review
Recent studies have illuminated a remarkable diversity and abundance of microbes living on and within the human body. While we are beginning to appreciate associations of certain bacteria and genes with particular host physiological states, considerable information is lacking about the relevant functional activities of the human microbiota. The human gut microbiome encodes tremendous potential for the biosynthesis and transformation of compounds that are important for both microbial and host physiology. Implementation of chemical knowledge and techniques will be required to improve our understanding of the biochemical diversity of the human microbiota. Such efforts include the characterization of novel microbial enzymes and pathways, isolation of microbial natural products, and development of tools to modulate biochemical functions of the gut microbiota. Ultimately, a molecular understanding of gut microbial activities will be critical for elucidating and manipulating these organisms' contributions to human health and disease.
Topics: Bacteria; Biological Products; Gastrointestinal Microbiome; Gastrointestinal Tract; Health; Humans; Metabolic Networks and Pathways
PubMed: 26933733
DOI: 10.1016/j.chembiol.2015.12.008 -
Microbiology Spectrum Dec 2022Bacteria can be associated with male infertility. Antibacterial substances (e.g., zinc-containing proteins, antimicrobial peptides) in ejaculates might impair the growth...
Bacteria can be associated with male infertility. Antibacterial substances (e.g., zinc-containing proteins, antimicrobial peptides) in ejaculates might impair the growth of bacteria in culture. We therefore wanted to test if removing antibacterial substances by washing the ejaculate could improve the detection of bacteria in culture. All ejaculates from patients ≥18 years old, which were obtained for routine diagnostics to assess male infertility were included in this study (no exclusion criteria were applied). Test samples were diluted with 2 mL sterile 0.45% saline, vortexed, and centrifuged (5 min; 7.5 × ). After the removal of 2 mL of the supernatant and resuspension, 10 μL of the pellet was used for aerobic and anaerobic culture. Control samples were cultured identically but without washing. Species identification was done with matrix-assisted laser desorption ionization-time of flight mass spectrometry. A total of 186 samples were included. The data set was stratified into five groups (Gram-negative rods [GNR], anaerobes [AN], spp. [EC], coagulase-negative staphylococci [CNS], and viridans streptococci [VS]). Compared to the control arm, the test arm revealed significant lower proportions for CNS (59.1% versus 44.6%, < 0.01) and VS (53.8% versus 41.9%, = 0.03). Similarly, slightly lower proportions of GNR (16.1% versus 15.1%, = 0.89), AN (19.9% versus 17.2%, = 0.5), and EC (25.3% versus 23.1%, = 0.63) were observed. The medians of CFU were lower in test samples compared to the control samples (6.5 × 10 versus 2.5 × 10, < 0.01) for any bacterial growth. Lower colony counts were also observed for individual bacterial groups. In conclusion, preculture washing of ejaculates results in a decrease in total bacteria count and culture-positive samples. This study compares two methods for processing ejaculate samples from men undergoing investigations for infertility. The method of sample washing and centrifugation was compared to the standard method of direct inoculation and culture. The study hypothesis was that preprocessing of samples may increase bacterial yield by removing bactericidal substances from semen. However, we found that washing ejaculate samples before microbiological culture did not improve the detection of bacteria and led to a reduction in colony counts.
Topics: Humans; Male; Adolescent; Bacteria; Semen; Anti-Bacterial Agents; Gram-Negative Bacteria; Bacteria, Anaerobic; Infertility, Male; Staphylococcus
PubMed: 36321892
DOI: 10.1128/spectrum.03269-22 -
Journal of Medical Microbiology Nov 2019Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial... (Review)
Review
Over the past century, numerous studies have used oral biofilm models to investigate growth kinetics, biofilm formation, structure and composition, antimicrobial susceptibility and host-pathogen interactions. animal models provide useful models of some oral diseases; however, these are expensive and carry vast ethical implications. Oral biofilms grown or maintained offer a useful platform for certain studies and have the advantages of being inexpensive to establish and easy to reproduce and manipulate. In addition, a wide range of variables can be monitored and adjusted to mimic the dynamic environmental changes at different sites in the oral cavity, such as pH, temperature, salivary and gingival crevicular fluid flow rates, or microbial composition. This review provides a detailed insight for early-career oral science researchers into how the biofilm models used in oral research have progressed and improved over the years, their advantages and disadvantages, and how such systems have contributed to our current understanding of oral disease pathogenesis and aetiology.
Topics: Animals; Bacteria; Bacterial Physiological Phenomena; Biofilms; Humans; Mouth
PubMed: 31524581
DOI: 10.1099/jmm.0.001063