Recent Perspectives on Gene-Microbe Interactions Determining Predisposition to Otitis Media

A Comprehensive Review on Biofilms in Otorhinolaryngology: Understanding the Pathogenesis, Diagnosis, and Treatment Strategies

Biofilms, structured communities of microorganisms encased in a self-produced matrix, pose significant challenges in otorhinolaryngology due to their role in chronic and recurrent infections affecting the ear, nose, and throat (ENT) region. This review provides an overview of biofilms, emphasizing their formation, pathogenesis, diagnosis, and treatment strategies in otorhinolaryngological disorders. Biofilms are pivotal in chronic rhinosinusitis (CRS), otitis media, laryngopharyngeal reflux (LPR), and tonsillitis, contributing to treatment resistance and disease recurrence. Current diagnostic techniques, including imaging modalities, microbiological cultures, and molecular techniques, are discussed, alongside emerging technologies. Treatment strategies, ranging from conventional antibiotics to alternative therapies, such as biofilm disruptors, phage therapy, and immunomodulation, are evaluated in terms of their efficacy and potential clinical applications. The review underscores the significance of understanding biofilms in otorhinolaryngology and highlights the need for tailored approaches to diagnosis and management to improve patient outcomes.

AMP-Coated TiO2 Doped ZnO Nanomaterials Enhanced Antimicrobial Activity and Efficacy in Otitis Media Treatment by Elevating Hydroxyl Radical Levels

Background

In the past decades, antimicrobial resistance (AMR) has been a major threat to global public health. Long-term, chronic otitis media is becoming more challenging to treat, thus the novel antibiotic alternative agents are much needed.

Methods

ZnO@TiO2@AMP (ATZ NPs) were synthesized through a solvothermal method and subjected to comprehensive characterization. The in vitro and in vivo antibacterial effect and biocompatibility of ATZ NPs were evaluated. For the antibacterial mechanism exploration, we utilized the Electron Paramagnetic Resonance (EPR) Spectrometer to detect and analyze the hydroxyl radicals produced by ATZ NPs.

Results

ATZ NPs exhibited a spherical structure of 99.85 nm, the drug-loading rate for ZnO was 20.73%, and AMP within ATZ NPs was 41.86%. Notably, the Minimum Inhibitory Concentration (MIC) value of ATZ NPs against Staphylococcus aureus (S. aureus), methicillin-resistant Staphylococcus aureus (MRSA), and Streptococcus pneumoniae (S. pneumoniae) were 10 μg/mL, and Minimum Bactericidal Concentration (MBC) value of ATZ NPs against S. aureus, and S. pneumoniae were 50 μg/mL. In comparison to the model group, the treatment of otitis media with ATZ NPs significantly reduces inflammatory exudation in the middle ear cavity, with no observable damage to the tympanic membrane. Both in vivo and in vitro toxicity tests indicating the good biocompatibility of ATZ NPs. Moreover, EPR spectroscopy results highlighted the superior ability of ATZ NPs to generate hydroxyl radicals (·OH) compared to ZnO NPs.

Conclusion

ATZ NPs exhibited remarkable antibacterial properties both in vivo and in vitro. This innovative application of advanced ATZ NPs, bringing great promise for the treatment of otitis media.

Circulating tumor HPV DNA assessments after surgery for human papilloma virus-associated oropharynx carcinoma

PURPOSE

To understand the utility of circulating tumor human papillomavirus DNA (ctHPVDNA) blood testing for HPV-associated oropharynx squamous cell carcinoma (HPV + OPSCC) after definitive surgery.

MATERIALS AND METHODS

Prospective cohort study of HPV(+)OPSCC patients with ctHPVDNA test data to assess its accuracy in detecting biopsy-confirmed disease at various post-treatment time points. Eligible patients had p16(+)/HPV(+) OPSCC and ctHPVDNA testing performed at any time pre-operatively and/or postoperatively. In cases of recurrence, patients were excluded from analysis if ctHPVDNA testing was not performed within 6 months of biopsy.

RESULTS

196 all-treatment-type patients had at least one PT ctHPVDNA test. The initial post-treatment (PT) ctHPVDNA sensitivity, specificity, PPV, and NPV were 69.2 % (9/13), 96.7 % (177/183), 60.0 % (9/15), and 97.8 % (177/181). 61 surgery alone (SA) patients underwent 128 PT tests. The initial PT SA ctHPVDNA sensitivity, specificity, PPV, and NPV were 100 % (2/2), 96.0 % (48/50), 50 % (2/4), and 100 % (48/48). 35 of 61 (57.4 %) SA patients had NCCN-based histopathologic indications for adjuvant (chemo)radiation but declined. 3 of 35 (8.57 %) had a positive PT ctHPVDNA test of which 1 of 3 (33 %) had biopsy-proven recurrence. Prospectively, ten patients had a PreT positive ctHPVDNA, underwent SA, refused adjuvant treatment, had an undetectable ctHPVDNA within 2 weeks of SA, and remained free of disease (mean 10.3 months).

CONCLUSION

The high specificity and NPV of ctHPVDNA after SA suggest ctHPVDNA may have a role in determining the omission of PT adjuvant (chemo)radiation in select patients.

Ginsenoside Rg1 modulates intestinal microbiota and supports re-generation of immune cells in dexamethasone-treated mice

Ginsenoside Rg1 is one of the major ginsenosides found in roots of Panax ginseng and Panax notoginseng. Ginsenoside Rg1 is known to possess various biological activities including immunity enhancement activity. However, it is not clear whether the regulation of immune function by Rg1 is related to the intestinal microbiota. In the present study, the immuno-modulatory and gut microbiota-reshaping effects of ginsenoside Rg1 were evaluated. Ginsenoside Rg1 acts as an immune-enhancing agent to increase spleen index and the number of T, B and dendritic cells in dexamethasone (Dex)-treated mice. Ginsenoside Rg1 also increased the production of sIgA and regulated the expression of interleukin 2 (IL-2), IL-4, IL-10 and IFN-γ. Meanwhile, Rg1 administration regulated the structure of intestinal microbiota. The relative abundance of mouse intestinal microbial groups, such as Alistipes, Ruminococcaceae, Lachnospiraceae, and Roseburia were increased by Rg1 administration, whereas a decrease in the potential pathogens like Helicobacteraceae, Dubosiella, Mycoplasma, Alloprevotella, Allobaculum was observed. Moreover, Rg1 metabolites of Lachnospiraceae bacterium enhanced the proliferation of CD4+ T cells and T regulatory (Treg) cells. Ginsenoside Rg1 improved the inflammatory condition of the colonic tissue and repaired the destructed mucosal barrier. This study suggested that Rg1 strengthens immunity with regulating the homeostasis of intestinal microbiota in mice.

Genomic Stability and Genetic Defense Systems in Dolosigranulum pigrum, a Candidate Beneficial Bacterium from the Human Microbiome

Dolosigranulum pigrum is positively associated with indicators of health in multiple epidemiological studies of human nasal microbiota. Knowledge of the basic biology of D. pigrum is a prerequisite for evaluating its potential for future therapeutic use; however, such data are very limited. To gain insight into D. pigrum's chromosomal structure, pangenome, and genomic stability, we compared the genomes of 28 D. pigrum strains that were collected across 20 years. Phylogenomic analysis showed closely related strains circulating over this period and closure of 19 genomes revealed highly conserved chromosomal synteny. Gene clusters involved in the mobilome and in defense against mobile genetic elements (MGEs) were enriched in the accessory genome versus the core genome. A systematic analysis for MGEs identified the first candidate D. pigrum prophage and insertion sequence. A systematic analysis for genetic elements that limit the spread of MGEs, including restriction modification (RM), CRISPR-Cas, and deity-named defense systems, revealed strain-level diversity in host defense systems that localized to specific genomic sites, including one RM system hot spot. Analysis of CRISPR spacers pointed to a wealth of MGEs against which D. pigrum defends itself. These results reveal a role for horizontal gene transfer and mobile genetic elements in strain diversification while highlighting that in D. pigrum this occurs within the context of a highly stable chromosomal organization protected by a variety of defense mechanisms. IMPORTANCE Dolosigranulum pigrum is a candidate beneficial bacterium with potential for future therapeutic use. This is based on its positive associations with characteristics of health in multiple studies of human nasal microbiota across the span of human life. For example, high levels of D. pigrum nasal colonization in adults predicts the absence of Staphylococcus aureus nasal colonization. Also, D. pigrum nasal colonization in young children is associated with healthy control groups in studies of middle ear infections. Our analysis of 28 genomes revealed a remarkable stability of D. pigrum strains colonizing people in the United States across a 20-year span. We subsequently identified factors that can influence this stability, including genomic stability, phage predators, the role of MGEs in strain-level variation, and defenses against MGEs. Finally, these D. pigrum strains also lacked predicted virulence factors. Overall, these findings add additional support to the potential for D. pigrum as a therapeutic bacterium.

The Versatility of Opportunistic Infections Caused by Gemella Isolates Is Supported by the Carriage of Virulence Factors From Multiple Origins

The molecular basis of the pathogenesis of the opportunistic invasive infections caused by isolates of the Gemella genus remains largely unknown. Moreover, inconsistencies in the current species assignation were detected after genome-level comparison of 16 public Gemella isolates. A literature search detected that, between the two most pathogenic species, Gemella morbillorum causes about twice the number of cases compared to Gemella haemolysans. These two species shared their mean diseases - sepsis and endocarditis - but differed in causing other syndromes. A number of well-known virulence factors were harbored by all species, such as a manganese transport/adhesin sharing 83% identity from oral endocarditis-causing streptococci. Likewise, all Gemellae carried the genes required for incorporating phosphorylcholine into their cell walls and encoded some choline-binding proteins. In contrast, other proteins were species-specific, which may justify the known epidemiological differences. G. haemolysans, but not G. morbillorum, harbor a gene cluster potentially encoding a polysaccharidic capsule. Species-specific surface determinants also included Rib and MucBP repeats, hemoglobin-binding NEAT domains, peptidases of C5a complement factor and domains that recognize extracellular matrix molecules exposed in damaged heart valves, such as collagen and fibronectin. Surface virulence determinants were associated with several taxonomically dispersed opportunistic genera of the oral microbiota, such as Granulicatella, Parvimonas, and Streptococcus, suggesting the existence of a horizontally transferrable gene reservoir in the oral environment, likely facilitated by close proximity in biofilms and ultimately linked to endocarditis. The identification of the Gemella virulence pool should be implemented in whole genome-based protocols to rationally predict the pathogenic potential in ongoing clinical infections caused by these poorly known bacterial pathogens.