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World Journal of Gastroenterology Aug 2015Relation between the gut microbiota and human health is being increasingly recognised. It is now well established that a healthy gut flora is largely responsible for... (Review)
Review
Relation between the gut microbiota and human health is being increasingly recognised. It is now well established that a healthy gut flora is largely responsible for overall health of the host. The normal human gut microbiota comprises of two major phyla, namely Bacteroidetes and Firmicutes. Though the gut microbiota in an infant appears haphazard, it starts resembling the adult flora by the age of 3 years. Nevertheless, there exist temporal and spatial variations in the microbial distribution from esophagus to the rectum all along the individual's life span. Developments in genome sequencing technologies and bioinformatics have now enabled scientists to study these microorganisms and their function and microbe-host interactions in an elaborate manner both in health and disease. The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens. Several factors play a role in shaping the normal gut microbiota. They include (1) the mode of delivery (vaginal or caesarean); (2) diet during infancy (breast milk or formula feeds) and adulthood (vegan based or meat based); and (3) use of antibiotics or antibiotic like molecules that are derived from the environment or the gut commensal community. A major concern of antibiotic use is the long-term alteration of the normal healthy gut microbiota and horizontal transfer of resistance genes that could result in reservoir of organisms with a multidrug resistant gene pool.
Topics: Age Factors; Anti-Bacterial Agents; Bacteriological Techniques; Bacteroidetes; Computational Biology; Diet; Firmicutes; Gastrointestinal Microbiome; Health Status; Homeostasis; Host-Pathogen Interactions; Humans; Intestines; Prebiotics; Probiotics; Synbiotics
PubMed: 26269668
DOI: 10.3748/wjg.v21.i29.8787 -
Clinical Microbiology Reviews Dec 2022All modern advances notwithstanding, pneumonia remains a common infection with substantial morbidity and mortality. Understanding of the etiology of pneumonia continues... (Review)
Review
All modern advances notwithstanding, pneumonia remains a common infection with substantial morbidity and mortality. Understanding of the etiology of pneumonia continues to evolve as new techniques enable identification of already known organisms and as new organisms emerge. We now review the etiology of pneumonia (at present often called "community-acquired pneumonia") beginning with classic bacteriologic techniques, which identified Streptococcus pneumoniae as the overwhelmingly common cause, to more modern bacteriologic studies, which emphasize Haemophilus influenzae, Staphylococcus aureus, Moraxella catarrhalis, , Pseudomonas, and normal respiratory flora. Urine antigen detection is useful in identifying and pneumococcus. The low yield of bacteria in recent studies is due to the failure to obtain valid sputum samples before antibiotics are administered. The use of high-quality sputum specimens enables identification of recognized ("typical") bacterial pathogens as well as a role for commensal bacteria ("normal respiratory flora"). Nucleic acid amplification technology for viruses has revolutionized diagnosis, showing the importance of viral pneumonia leading to hospitalization with or without coinfecting bacterial organisms. Quantitative PCR study of sputum is in its early stages of application, but regular detection of high counts of bacterial DNA from organisms that are not seen on Gram stain or grown in quantitative culture presents a therapeutic dilemma. This finding may reflect the host microbiome of the respiratory tract, in which case treatment may not need to be given for them. Finally, host transcriptional signatures might enable clinicians to distinguish between viral and bacterial pneumonia, an important practical consideration.
Topics: Adult; Humans; Bacteriology; Pneumonia, Bacterial; Streptococcus pneumoniae; Pneumonia, Viral; Bacteria; Community-Acquired Infections
PubMed: 36165783
DOI: 10.1128/cmr.00015-22 -
Indian Journal of Medical Microbiology 2013Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and the internal organs. Sometimes instead... (Review)
Review
Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and the internal organs. Sometimes instead of bacteria, inflammatory compounds are responsible for clinical symptoms as in systemic inflammatory response syndrome (SIRS). The difference between sepsis and SIRS is that pathogenic bacteria are isolated from patients with sepsis but not with those of SIRS. Bacterial translocation occurs more frequently in patients with intestinal obstruction and in immunocompromised patients and is the cause of subsequent sepsis. Factors that can trigger bacterial translocation from the gut are host immune deficiencies and immunosuppression, disturbances in normal ecological balance of gut, mucosal barrier permeability, obstructive jaundice, stress, etc. Bacterial translocation occurs through the transcellular and the paracellular pathways and can be measured both directly by culture of mesenteric lymph nodes and indirectly by using labeled bacteria, peripheral blood culture, detection of microbial DNA or endotoxin and urinary excretion of non-metabolisable sugars. Bacterial translocation may be a normal phenomenon occurring on frequent basis in healthy individuals without any deleterious consequences. But when the immune system is challenged extensively, it breaks down and results in septic complications at different sites away from the main focus. The factors released from the gut and carried in the mesenteric lymphatics but not in the portal blood are enough to cause multi-organ failure. Thus, bacterial translocation may be a promoter of sepsis but not the initiator. This paper reviews literature on the translocation of gut flora and its role in causing sepsis.
Topics: Bacterial Translocation; Gastrointestinal Tract; Humans; Sepsis
PubMed: 24064638
DOI: 10.4103/0255-0857.118870 -
EMBO Reports Jul 2006The intestinal microflora is a positive health asset that crucially influences the normal structural and functional development of the mucosal immune system. Mucosal... (Review)
Review
The intestinal microflora is a positive health asset that crucially influences the normal structural and functional development of the mucosal immune system. Mucosal immune responses to resident intestinal microflora require precise control and an immunosensory capacity for distinguishing commensal from pathogenic bacteria. In genetically susceptible individuals, some components of the flora can become a liability and contribute to the pathogenesis of various intestinal disorders, including inflammatory bowel diseases. It follows that manipulation of the flora to enhance the beneficial components represents a promising therapeutic strategy. The flora has a collective metabolic activity equal to a virtual organ within an organ, and the mechanisms underlying the conditioning influence of the bacteria on mucosal homeostasis and immune responses are beginning to be unravelled. An improved understanding of this hidden organ will reveal secrets that are relevant to human health and to several infectious, inflammatory and neoplastic disease processes.
Topics: Animals; Bacteria; Digestive System; Digestive System Diseases; Germ-Free Life; Homeostasis; Humans; Immunity, Mucosal; Intestinal Mucosa; Models, Biological
PubMed: 16819463
DOI: 10.1038/sj.embor.7400731 -
Frontiers in Cellular and Infection... 2020Yeasts of the genus, , formerly known as , are lipophilic yeasts, which are a part of the normal skin flora (microbiome). colonize the human skin after birth and must... (Review)
Review
Yeasts of the genus, , formerly known as , are lipophilic yeasts, which are a part of the normal skin flora (microbiome). colonize the human skin after birth and must therefore, as commensals, be normally tolerated by the human immune system. The yeasts also have a pathogenic potential where they can, under appropriate conditions, invade the stratum corneum and interact with the host immune system, both directly but also through chemical mediators. The species distribution on the skin and the pathogenetic potential of the yeast varies between different related diseases such as head and neck dermatitis, seborrheic dermatitis, pityriasis versicolor, and folliculitis. The diagnostic methods used to confirm the presence of yeasts include direct microcopy, culture based methods (often a combination of morphological features of the isolate combined with biochemical test), molecular based methods such as Polymerase Chain Reaction techniques, and Matrix Assisted Laser Desorption/Ionization-Time Of Flight mass spectrometry and the chemical imprint method Raman spectroscopy. Skin diseases caused by are usually treated with antifungal therapy and if there are associated inflammatory skin mechanisms this is often supplemented by anti-inflammatory therapy. The aim of this paper is to provide an overview of related skin disease, diagnostic methods and treatment options.
Topics: Dermatitis, Seborrheic; Folliculitis; Humans; Malassezia; Skin; Tinea Versicolor
PubMed: 32266163
DOI: 10.3389/fcimb.2020.00112 -
Frontiers in Cellular and Infection... 2023With the development of endoscopic technology, an increasing number of patients with esophageal disease are being diagnosed, although the underlying pathogenesis of many... (Review)
Review
With the development of endoscopic technology, an increasing number of patients with esophageal disease are being diagnosed, although the underlying pathogenesis of many esophageal diseases remains unclear. In recent years, a large number of studies have demonstrated that the occurrence and development of various intestinal diseases were related to intestinal flora. As a result, researchers have shifted their focus towards investigating esophageal flora to better understand the pathogenesis, early diagnosis, and treatment of esophageal diseases. This paper reviewed the normal esophageal flora and the changes of esophageal flora under different esophageal disease states. It was observed that there are distinct differences in the composition of esophageal microflora among Gastroesophageal Reflux, Barrett's esophagus, eosinophilic esophagitis and normal esophagus. The normal esophageal flora was dominated by gram-positive bacteria, particularly , while the esophageal flora under esophagitis was dominated by gram-negative bacteria. Furthermore, the diversity of esophageal flora is significantly decreased in patients with esophageal cancer. Several potential microbial biomarkers for esophageal cancer have been identified, among which showed a close association with esophageal squamous cell carcinoma's pathological stage and clinical stage.
Topics: Humans; Esophageal Neoplasms; Esophageal Squamous Cell Carcinoma; Barrett Esophagus; Esophageal Diseases
PubMed: 37274313
DOI: 10.3389/fcimb.2023.1145791 -
The Journal of Clinical and Aesthetic... Mar 2014Malassezia (Pityrosporum) folliculitis is a fungal acneiform condition commonly misdiagnosed as acne vulgaris. Although often associated with common acne, this condition... (Review)
Review
Malassezia (Pityrosporum) folliculitis is a fungal acneiform condition commonly misdiagnosed as acne vulgaris. Although often associated with common acne, this condition may persist for years without complete resolution with typical acne medications. Malassezia folliculitis results from overgrowth of yeast present in the normal cutaneous flora. Eruptions may be associated with conditions altering this flora, such as immunosuppression and antibiotic use. The most common presentation is monomorphic papules and pustules, often on the chest, back, posterior arms, and face. Oral antifungals are the most effective treatment and result in rapid improvement. The association with acne vulgaris may require combinations of both antifungal and acne medications. This article reviews and updates readers on this not uncommon, but easily missed, condition.
PubMed: 24688625
DOI: No ID Found