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Current Opinion in Gastroenterology Nov 2023This article aims to provide an up-to-date review of small intestinal bacterial overgrowth (SIBO), including etiology and risk factors, clinical manifestations,... (Review)
Review
PURPOSE OF REVIEW
This article aims to provide an up-to-date review of small intestinal bacterial overgrowth (SIBO), including etiology and risk factors, clinical manifestations, diagnostic evaluation for suspected SIBO, and therapeutic options.
RECENT FINDINGS
Recent advances in breath testing, capsule and urine-based testing have opened new avenues and improved diagnostic yield of SIBO. Nonantibiotic-based treatment strategies have shown promising results in initial trials.
SUMMARY
Small intestinal bacterial overgrowth (SIBO) is a condition defined by the excess bacteria or changes in bacterial composition of the small intestine. These are associated with various gastrointestinal (GI) symptoms such as bloating, abdominal distension, diarrhea, nutrient deficiencies, and even frank weight loss. Small bowel jejunal aspirate of >10 5 CFU/ml has traditionally been considered the gold standard for diagnosis. Glucose and lactulose breath testing have become more common in clinical practice as they are noninvasive, easily accessible, and have lower cost. Treatment focuses on the eradication of excess bacteria in the small bowel and is traditionally done with the use of oral antibiotics. Other emerging therapies may include probiotics, diet manipulation, and prokinetic agents.
Topics: Humans; Intestine, Small; Anti-Bacterial Agents; Lactulose; Bacteria; Diarrhea; Breath Tests
PubMed: 37751393
DOI: 10.1097/MOG.0000000000000971 -
The American Journal of Gastroenterology Apr 2024Antibiotic resistance is one of the main factors that determine the efficacy of treatments to eradicate Helicobacter pylori infection. Our aim was to evaluate the...
INTRODUCTION
Antibiotic resistance is one of the main factors that determine the efficacy of treatments to eradicate Helicobacter pylori infection. Our aim was to evaluate the effectiveness of first-line and rescue treatments against H. pylori in Europe according to antibiotics resistance.
METHODS
Prospective, multicenter, international registry on the management of H. pylori (European Registry on H. pylori Management). All infected and culture-diagnosed adult patients registered in the Spanish Association of Gastroenterology-Research Electronic Data Capture from 2013 to 2021 were included.
RESULTS
A total of 2,852 naive patients with culture results were analyzed. Resistance to clarithromycin, metronidazole, and quinolones was 22%, 27%, and 18%, respectively. The most effective treatment, regardless of resistance, were the 3-in-1 single capsule with bismuth, metronidazole, and tetracycline (91%) and the quadruple with bismuth, offering optimal cure rates even in the presence of bacterial resistance to clarithromycin or metronidazole. The concomitant regimen with tinidazole achieved an eradication rate of 99% (90/91) vs 84% (90/107) with metronidazole. Triple schedules, sequential, or concomitant regimen with metronidazole did not achieve optimal results. A total of 1,118 non-naive patients were analyzed. Resistance to clarithromycin, metronidazole, and quinolones was 49%, 41%, and 24%, respectively. The 3-in-1 single capsule (87%) and the triple therapy with levofloxacin (85%) were the only ones that provided encouraging results.
DISCUSSION
In regions where the antibiotic resistance rate of H. pylori is high, eradication treatment with the 3-in-1 single capsule, the quadruple with bismuth, and concomitant with tinidazole are the best options in naive patients. In non-naive patients, the 3-in-1 single capsule and the triple therapy with levofloxacin provided encouraging results.
Topics: Adult; Humans; Anti-Bacterial Agents; Bismuth; Clarithromycin; Drug Resistance, Microbial; Drug Therapy, Combination; Helicobacter Infections; Helicobacter pylori; Levofloxacin; Metronidazole; Prospective Studies; Tinidazole
PubMed: 37983769
DOI: 10.14309/ajg.0000000000002600 -
Frontiers in Cellular and Infection... 2024
Topics: Bacteria; Polymers; Humans
PubMed: 38725450
DOI: 10.3389/fcimb.2024.1415799 -
NPJ Biofilms and Microbiomes Mar 2024In environments characterized by extended multi-stress conditions, pathogens develop a variety of immune escape mechanisms to enhance their ability to infect the host.... (Review)
Review
In environments characterized by extended multi-stress conditions, pathogens develop a variety of immune escape mechanisms to enhance their ability to infect the host. The capsules, polymers that bacteria secrete near their cell wall, participates in numerous bacterial life processes and plays a crucial role in resisting host immune attacks and adapting to their niche. Here, we discuss the relationship between capsules and bacterial virulence, summarizing the molecular mechanisms of capsular regulation and pathogenesis to provide new insights into the research on the pathogenesis of pathogenic bacteria.
Topics: Bacterial Capsules; Virulence; Bacteria
PubMed: 38480745
DOI: 10.1038/s41522-024-00497-6 -
Biofilm Dec 2023Biofilm formation and capsule production are known microbial strategies used by bacterial pathogens to survive adverse conditions in the hospital environment. The...
Biofilm formation and capsule production are known microbial strategies used by bacterial pathogens to survive adverse conditions in the hospital environment. The relative importance of these strategies individually is unexplored. This project aims to compare the contributory roles of biofilm formation and capsule production in bacterial survival on hospital surfaces. Representative strains of bacterial species often causing hospital-acquired infections were selected, including , , , and . The importance of biofilm formation and capsule production on bacterial survival was evaluated by comparing capsule-positive wild-type and capsule-deficient mutant strains, and biofilm and planktonic growth modes respectively, against three adverse hospital conditions, including desiccation, benzalkonium chloride disinfection and ultraviolet (UV) radiation. Bacterial survival was quantitatively assessed using colony-forming unit (CFU) enumeration and the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and qualitatively by scanning electron microscopy (SEM). Correlations between capsule production and biofilm formation were further investigated. Biofilm formation contributed significantly to bacterial survival on hospital surface simulators, mediating high resistance to desiccation, benzalkonium chloride disinfection and UV radiation. The role of capsule production was minor and species-specific; encapsulated but not cells demonstrated slightly increased resistance to desiccation, and neither showed enhanced resistance to benzalkonium chloride. Interestingly, capsule production sensitized and to UV radiation. The loss of capsule in and enhanced biofilm formation, possibly by increasing cell surface hydrophobicity. In summary, this study confirms the crucial role of biofilm formation in bacterial survival on hospital surfaces. Conversely, encapsulation plays a relatively minor role and may even negatively impact bacterial biofilm formation and hospital survival.
PubMed: 36711324
DOI: 10.1016/j.bioflm.2023.100105 -
Nature Communications Jun 2023Escherichia coli is a leading cause of invasive bacterial infections in humans. Capsule polysaccharide has an important role in bacterial pathogenesis, and the K1...
Escherichia coli is a leading cause of invasive bacterial infections in humans. Capsule polysaccharide has an important role in bacterial pathogenesis, and the K1 capsule has been firmly established as one of the most potent capsule types in E. coli through its association with severe infections. However, little is known about its distribution, evolution and functions across the E. coli phylogeny, which is fundamental to elucidating its role in the expansion of successful lineages. Using systematic surveys of invasive E. coli isolates, we show that the K1-cps locus is present in a quarter of bloodstream infection isolates and has emerged in at least four different extraintestinal pathogenic E. coli (ExPEC) phylogroups independently in the last 500 years. Phenotypic assessment demonstrates that K1 capsule synthesis enhances E. coli survival in human serum independent of genetic background, and that therapeutic targeting of the K1 capsule re-sensitizes E. coli from distinct genetic backgrounds to human serum. Our study highlights that assessing the evolutionary and functional properties of bacterial virulence factors at population levels is important to better monitor and predict the emergence of virulent clones, and to also inform therapies and preventive medicine to effectively control bacterial infections whilst significantly lowering antibiotic usage.
Topics: Humans; Escherichia coli; Escherichia coli Infections; Virulence; Virulence Factors; Escherichia coli Proteins; Phylogeny
PubMed: 37322051
DOI: 10.1038/s41467-023-39052-w -
Human Vaccines & Immunotherapeutics Dec 2024Like the other invasive encapsulated bacteria, is also covered with a polysaccharide structure. Infants and elderly are most vulnerable to the invasive and noninvasive...
Like the other invasive encapsulated bacteria, is also covered with a polysaccharide structure. Infants and elderly are most vulnerable to the invasive and noninvasive diseases caused by . Although antibodies against polysaccharide capsule are efficient in eliminating , the T cell independent nature of the immune response against polysaccharide vaccines renders them weakly antigenic. The introduction of protein conjugated capsular polysaccharide vaccines helped overcome the weak immunogenicity of pneumococcal polysaccharides and decreased the incidence of pneumococcal diseases, especially in pediatric population. Conjugate vaccines elicit T cell dependent response which involve the interaction of specialized CD4+ T cells, called follicular helper T cells (Tfh) with germinal center B cells in secondary lymphoid organs. Despite their improved immunogenicity, conjugate vaccines still need to be administered three to four times in infants during the first 15 month of their life because they mount poor Tfh response. Recent studies revealed fundamental differences in the generation of Tfh cells between neonates and adults. As the portfolio of pneumococcal conjugate vaccines continues to increase, better understanding of the mechanisms of antibody development in different age groups will help in the development of pneumococcal vaccines tailored for different ages.
Topics: Infant; Adult; Infant, Newborn; Child; Humans; Aged; Pneumococcal Vaccines; Streptococcus pneumoniae; Pneumococcal Infections; Vaccines, Conjugate; Antibodies; Polysaccharides; Antibodies, Bacterial
PubMed: 38567485
DOI: 10.1080/21645515.2024.2336358 -
Survey of Ophthalmology 2023Streptococcus is a diverse bacterial genus that is part of the ocular surface microbiome implicated in conjunctivitis, keratitis, endophthalmitis, dacryocystitis, and... (Review)
Review
Streptococcus is a diverse bacterial genus that is part of the ocular surface microbiome implicated in conjunctivitis, keratitis, endophthalmitis, dacryocystitis, and orbital cellulitis that can lead to decreased visual acuity and require surgical intervention. The pathophysiology of S. pneumoniae is well-established and the role of the polysaccharide capsule, pneumolysin, neuraminidases, and zinc metalloproteinases in ocular infections described. Additionally, key virulence factors of the viridans group streptococci such as cytolysins and proteases have been outlined, but there is a paucity of research on the remaining streptococcus species. These virulence factors tend to result in aggressive disease. Clinically, S. pneumoniae is implicated in 2.7-41.2% of bacterial conjunctivitis cases, more predominant in the pediatric population, and is implicated in 1.8-10.7% of bacterial keratitis isolates. Streptococcus bacteria are significantly implicated in acute postoperative, postintravitreal, and bleb-associated endophthalmitis, responsible for 10.3-37.5, 29.4, and 57.1% of cases, respectively. Group A and B streptococcus endogenous endophthalmitis is rare, but has a very poor prognosis. Inappropriate prescription of antibiotics in cases of nonbacterial aetiology has contributed to increasing resistance, and a clinical index is needed to more accurately monitor this. Furthermore, there is an increasing need for prospective, surveillance studies of antimicrobial resistance in ocular pathogens, as well as point-of-care testing using molecular techniques.
Topics: Child; Humans; Prospective Studies; Streptococcus; Anti-Bacterial Agents; Endophthalmitis; Streptococcal Infections; Eye Infections, Bacterial; Streptococcus pneumoniae; Keratitis
PubMed: 36764397
DOI: 10.1016/j.survophthal.2023.02.001 -
Frontiers in Cellular and Infection... 2023The polysaccharide capsule of plays a major role in virulence, adherence to epithelial cells, and overall survival of the bacterium in the human host. Galactose,...
BACKGROUND
The polysaccharide capsule of plays a major role in virulence, adherence to epithelial cells, and overall survival of the bacterium in the human host. Galactose, mannose, and N-acetylglucosamine (GlcNAc) are likely to be relevant for metabolization in the nasopharynx, while glucose is the primary carbon source in the blood. In this study, we aim to further the understanding of the influence of carbon sources on pneumococcal growth, capsule biosynthesis, and subsequent adherence potential.
METHODS
We tested the growth behavior of clinical wild-type and capsule knockout strains, using galactose, GlcNAc, mannose, and glucose as carbon source for growth. We measured capsule thickness and quantified capsule precursors by fluorescein isothiocyanate (FITC)-dextran exclusion assays and P-nuclear magnetic resonance measurements, respectively. We also performed epithelial adherence assays using Detroit 562 cells and performed a transcriptome analysis (RNA sequencing).
RESULTS
We observed a reduced growth in galactose, mannose, and GlcNAc compared to growth in glucose and found capsular size reductions in mannose and GlcNAc compared to galactose and glucose. Additionally, capsular precursor measurements of uridine diphosphate-(UDP)-glucose and UDP-galactose showed less accumulation of precursors in GlcNAc or mannose than in glucose and galactose, indicating a possible link with the received capsular thickness measurements. Epithelial adherence assays showed an increase in adherence potential for a pneumococcal strain, when grown in mannose compared to glucose. Finally, transcriptome analysis of four clinical isolates revealed not only strain specific but also common carbon source-specific gene expression.
CONCLUSION
Our findings may indicate a careful adaption of the lifestyle of according to the monosaccharides encountered in the respective human niche.
Topics: Humans; Streptococcus pneumoniae; Galactose; Carbon; Mannose; Glucose; Uridine Diphosphate; Bacterial Capsules
PubMed: 38094742
DOI: 10.3389/fcimb.2023.1279119