Explore the vast range of titles available.

Moraxella catarrhalis is a pathobiont of the respiratory tract, responsible for ear infections in children and wheezing illnesses in children and adults with chronic respiratory diseases. Detection of M. catarrhalis during wheezing episodes in early life is associated with the development of persistent asthma. Moraxella catarrhalis is found almost exclusively within the human respiratory tract. This pathobiont is associated with ear infections and the development of respiratory illnesses, including allergies and asthma. Given the limited ecological distribution of M. catarrhalis , we hypothesized that we could leverage the nasal microbiomes of healthy children without M. catarrhalis to identify bacteria that may represent potential sources of therapeutics. Rothia was more abundant in the noses of healthy children compared to children with cold symptoms and M. catarrhalis . We cultured Rothia from nasal samples and determined that most isolates of Rothia dentocariosa and “ Rothia similmucilaginosa ” were able to fully inhibit the growth of M. catarrhalis in vitro , whereas isolates of Rothia aeria varied in their ability to inhibit M. catarrhalis . Using comparative genomics and proteomics, we identified a putative peptidoglycan hydrolase called s ecreted a nti g en A (SagA). This protein was present at higher relative abundance in the secreted proteomes of R. dentocariosa and R. similmucilaginosa than in those from non-inhibitory R. aeria , suggesting that it may be involved in M. catarrhalis inhibition. We produced SagA from R. similmucilaginosa in Escherichia coli and confirmed its ability to degrade M. catarrhalis peptidoglycan and inhibit its growth. We then demonstrated that R. aeria and R. similmucilaginosa reduced M. catarrhalis levels in an air-liquid interface culture model of the respiratory epithelium. Together, our results suggest that Rothia restricts M. catarrhalis colonization of the human respiratory tract in vivo . IMPORTANCE Moraxella catarrhalis is a pathobiont of the respiratory tract, responsible for ear infections in children and wheezing illnesses in children and adults with chronic respiratory diseases. Detection of M. catarrhalis during wheezing episodes in early life is associated with the development of persistent asthma. There are currently no effective vaccines for M. catarrhalis , and most clinical isolates are resistant to the commonly prescribed antibiotics amoxicillin and penicillin. Given the limited niche of M. catarrhalis , we hypothesized that other nasal bacteria have evolved mechanisms to compete against M. catarrhalis . We found that Rothia are associated with the nasal microbiomes of healthy children without Moraxella. Next, we demonstrated that Rothia inhibit M. catarrhalis in vitro and on airway cells. We identified an enzyme produced by Rothia called SagA that degrades M. catarrhalis peptidoglycan and inhibits its growth. We suggest that Rothia or SagA could be developed as highly specific therapeutics against M. catarrhalis .

Introduction: Rothia mucilaginosa is a rare cause of endocarditis, typically seen in intravenous (IV) drug users who use needles contaminated with saliva. However, it is rare in individuals who are immunocompetent, have no history of valvular disease, or have not undergone valvular repair. Definitive management of R mucilaginosa endocarditis is valvular repair, but this procedure can be delayed in the setting of intracranial hemorrhage. Case Report: We document the case of a 35-year-old male IV drug user who developed R mucilaginosa endocarditis, resulting in severe neurologic sequelae due to septic emboli. The patient presented to the emergency department (ED) where work-up revealed a clinical presentation consistent with endocarditis resulting in septic emboli. He was later admitted to the neurosurgical and cardiac intensive care units, where he underwent thrombectomy, monitoring ofhis intraparenchymal hemorrhage (IPH), and mitral valve repair. This case highlights the patient’s functional neurologic outcome following delayed mitral valve repair due to IPH. Conclusion: This case report highlights a rare form of R mucilaginosa endocarditis recognized in the ED, with a hospital course including thrombectomy, IPH monitoring, and mitral valve repair. The patient had progressive neurologic sequelae given delayed mitral valve repair due to concerns that procedural heparinization would worsen his IPH. Given functional decline, the patient underwent mitral valve repair on hospital day six without worsening of his IPH, demonstrating that current guidelines to delay mitral valve repair by four weeks in the setting of intracranial hemorrhage may be too strict for patients who are high risk for continued showering of septic emboli.

In this pilot study, we investigated the bacterial changes introduced on the subgingival, tongue, and saliva microbiota during fixed orthodontic treatment, with or without daily administration of nitrate-containing beet juice for 2 weeks in 22 individuals with good general health. We followed clinical parameters in combination with microbiota changes before, after 2 weeks, and after 6 months of treatment with fixed orthodontic appliances. In accordance with variations in community composition at the sampling sites, effects to orthodontic treatment differed. Subgingival communities responded promptly to orthodontic treatment with no additional structural changes over time, whereas saliva and tongue communities were affected only after extended treatment. Periodontal pathogens such as Selenomonas sputigena were enriched in subgingival communities, whereas Streptococcus mutans was enriched in saliva. Specifically, Rothia mucilaginosa increased tremendously in relative abundance in both tongue and saliva communities. The effect of beet juice on microbial composition was significant in subgingival samples even though the differences were not mirrored in single differentially distributed genera or species. This indicates changes in the complete subgingival microbial net of interacting species. However, the prevention of Corynebacterium matruchotii enrichment by beet juice may be important for prevention of biofilm formation. Enrichment of Neisseria flavescens group bacteria and Abiotrophia and depletion of different Actinomyces and Stomatobaculum were observed on tongue communities. We conclude that subgingival microbiota are rapidly affected by fixed orthodontic appliances and can be positively influenced by regular administration of nitrate-containing juice. Key points • The subgingival site, tongue, and saliva contain different microbiota • The microbiota react differently to orthodontic treatment and beet juice • Key genera and species affected by treatments were identified

The prevalence of obesity is rapidly increasing among adolescents in Kuwait. The ecological and dynamic changes within the oral microbiota during this developmental stage remain elusive. This study aimed to investigate the impact of body mass index (BMI) on salivary microbiome diversity and composition in Kuwaiti adolescents by utilizing next-generation sequencing technologies. DNA was extracted from saliva samples of 62 Kuwaiti adolescents enrolled in the nationwide Kuwait Healthy Lifestyle Study, categorized as underweight, normal weight, overweight, and obese based on their BMI percentiles. The 16 S metagenomic profiling was performed to identify the key oral lineages and genera associated with obesity through comprehensive analysis involving taxonomic composition, co-occurrence networks, and key metabolic profiles. Our study reveals an inverse relationship between oral bacterial diversity and obesity status in Kuwaiti adolescents. The obese and overweight groups showed comparatively low microbial taxa compared to those of normal weight. We identified three potential microbial biomarkers linked to obesity and overweight: Prevotella melaninogenica , Veillonella dispar , and Veillonella parvula . The abundance of Neisseria subflava and Rothia mucilaginosa in normal weight adolescents indicates their role in weight homeostasis. In- silico analysis of differentially expressed microbiota revealed increased activity of major metabolic enzymes such as glucose- 6- phosphate dehydrogenase, pyruvate oxidase, and glycogen phosphorylase, along with oxidative stress- related enzymes including superoxide reductase and glutathione peroxidase in obese and over-weight adolescents. Conversely, normal weight adolescents exhibited heightened activity of pyruvate synthase and tRNA- methyltransferase, which are linked to antioxidative pathways and balanced energy metabolism. Our study highlights taxonomic and functional shifts in the oral microbiota of Kuwaiti adolescents across varying BMI categories, signifying key microbial markers that could pave the way for future research focused on microbiome- targeted interventions in obesity management.

Multi-drug resistant (MDR) bacterial cells embedded in biofilm matrices can lead to the development of chronic cariogenesis. Here, we isolated and identified three Gram-positive MDR oral cocci, (1) SJM-04, (2) SJM-38, and (3) SJM-65, and characterized them morphologically, biochemically, and by 16S rRNA gene-based phylogenetic analysis as Georgenia sp., Staphylococcus saprophyticus, and Rothia mucilaginosa, respectively. These three oral isolates exhibited antibiotic-resistance against nalidixic acid, tetracycline, cefuroxime, methicillin, and ceftazidime. Furthermore, these Gram positive MDR oral cocci showed significant (p < 0.05) variations in their biofilm forming ability under different physicochemical conditions, that is, at temperatures of 28, 30, and 42 °C, pH of 6.4, 7.4, and 8.4, and NaCl concentrations from 200 to 1000 µg/mL. Exposure of oral isolates to TiO2NPs (14.7 nm) significantly (p < 0.05) reduced planktonic cell viability and biofilm formation in a concentration-dependent manner, which was confirmed by observing biofilm architecture by scanning electron microscopy (SEM) and optical microscopy. Overall, these results have important implications for the use of tetragonal anatase phase TiO2NPs (size range 5–25 nm, crystalline size 13.7 nm, and spherical shape) as an oral antibiofilm agent against Gram positive cocci infections. We suggest that TiO2NPs pave the way for further applications in oral mouthwash formulations and antibiofilm dental coatings.

Background The possibility that smokeless tobacco may contribute to oral carcinogenesis by influencing the oral microbiome has not been explored. This preliminary cross-sectional study sought to assess the effect of using shammah, a form of smokeless tobacco prevalent in Arabia, on the tongue microbiome. Tongue scarping samples were obtained from 29 shammah users (SU; 27.34 ± 6.9 years) and 23 shammah non-users (SNU; 27.7 ± 7.19 years) and analyzed with 16S rRNA gene sequencing (V1-V3). Species-level taxonomy assignment of the high-quality, merged reads was obtained using a previously described BLASTn-based algorithm. Downstream analyses were performed with QIIME, LEfSe, and R. Results A total of 178 species, belonging to 62 genera and 8 phyla were identified. Genera Streptococcus , Leptotrichia , Actinomyces , Veillonella , Haemophilus , Prevotella and Neisseria accounted for more than 60% of the average microbiome. There were no differences between the two groups in species richness and alpha-diversity, but PCoA showed significant separation ( P  = 0.015, ANOSIM). LEfSe analysis identified 22 species to be differentially abundant between the SU and SNU. However, only 7 species maintained a false discovery rate of ≤0.2 and could cluster the two groups separately: Rothia mucilaginosa , Streptococcus sp. oral taxon 66, Actinomyces meyeri , Streptococcus vestibularis Streptococcus sanguinis and a potentially novel Veillonella species in association with SU, and Oribacterium asaccharolyticum with SNU. Conclusion These preliminary results indicate that shammah use induces tongue microbiome changes including enrichment of several species with high acetaldehyde production potential, which warrants further investigation.

The highest number (35.1% of global incident cases) of new oropharyngeal (OP) and hypopharyngeal (HP) cancer cases was reported in South-Central Asia. The highest incidence of HP cancer in India was reported in East Khasi Hills District of Meghalaya, Aizawl District of Mizoram, and Kamrup Urban District of Assam. HP and OP cancer showed the highest mortality rate, worst prognoses and the highest rate of nodal metastases and distant metastases. Thus, research is required to detect specific biomarkers for early prevention and diagnosis for these cancers. Oral microbiome signatures in saliva are considered as a potential diagnostic biomarker for OP and HP cancer. Bacterial profile alterations in OP and HP cancer have not been reported in India population, to establish the association of oral bacteria in the progression of OP and HP cancer; we studied bacterial communities in saliva of eight OP and seven HP cancer patients as compared to healthy controls using 16S rRNA V3–V4 region sequencing. The higher abundance of Haemophilus parainfluenzae, Haemophilus influenzae and Prevotella copri and lower abundance of Rothia mucilaginosa, Aggregatibacter segnis, Veillonella dispar, Prevotella nanceiensis, Rothia aeria, Capnocytophaga ochracea, Neisseria bacilliformis, Prevotella nigrescens and Selenomonas noxia in saliva of OP and HP cancer patients may be considered as a non-invasive diagnostic biomarker for OP and HP cancer patients. Streptococcus anginosus may be considered as a non-invasive diagnostic biomarker for OP cancer patients only. Therefore, evaluation of salivary microbial biomarkers may be informative to understand the pathobiology and carcinogenesis of OP and HP cancer.

Background Previous observational studies have indicated a correlation between the skin microbiome and Type 2 diabetes (T2DM). It is hypothesized that this causal relationship may be influenced by inflammatory responses. However, these factors as determinants of T2DM remain largely unexplored. Method This study incorporated data from the GWAS database on the skin microbiome, 91 types of inflammatory cytokines, and T2DM. We employed two-sample MR and multivariable MR methods to assess the correlation between the skin microbiome and T2DM, and to investigate whether this correlation is affected by inflammatory cytokines. Results The results of the two-sample MR analysis indicate that within the skin microbiome, genetically predicted genus: Acinetobacter, class: Alphaproteobacteria, genus: Bacteroides, ASV005[Propionibacterium granulosum], and ASV072[Rothia mucilaginosa] are associated with an increased risk of T2DM, while phylum: Proteobacteria, genus: Enhydrobacter, family: Clostridiales, ASV006[Staphylococcus hominis] serve as protective factors against T2DM. Among the inflammatory cytokines, levels of Macrophage colony-stimulating factor 1, Tumor necrosis factor receptor superfamily member 9, Urokinase-type plasminogen activator, and C–C motif chemokine 28 are associated with an increased risk of T2DM. Multivariable MR analysis further revealed that Macrophage colony-stimulating factor 1 levels act as a mediating factor between ASV072[Rothia mucilaginosa] and T2DM. Conclusion In this study, we found a connection between the skin microbiome and T2DM, with inflammatory cytokines playing a key role in this relationship. This research helps us better understand this complex link and shows that addressing inflammation is important for preventing and treating diabetes. This could greatly benefit public health by reducing the impact of diabetes and its complications. Our results suggest that future studies should explore the specific biological interactions between the skin microbiome and diabetes to develop more effective risk management and treatment strategies from a microbial perspective.

The communication language of the human oral microbiota is vastly underexplored. However, a few studies have shown that specialized small molecules encoded by BGCs have critical roles such as in colonization resistance against pathogens and quorum sensing. Here, by using a genome mining approach in combination with compound screening of growth cultures, we identified that the commensal oral community member R. mucilaginosa harbors a catecholate-siderophore BGC, which is responsible for the biosynthesis of enterobactin. The iron-scavenging role of enterobactin is known to have positive effects on the host’s iron pool and negative effects on host immune function; however, its role in oral health remains unexplored. R. mucilaginosa was previously identified as an abundant community member in cystic fibrosis, where bacterial iron cycling plays a major role in virulence development. With respect to iron’s broad biological importance, iron-chelating enterobactin may explain R. mucilaginosa ’s colonization success in both health and disease. Next-generation sequencing studies of saliva and dental plaque from subjects in both healthy and diseased states have identified bacteria belonging to the Rothia genus as ubiquitous members of the oral microbiota. To gain a deeper understanding of molecular mechanisms underlying the chemical ecology of this unexplored group, we applied a genome mining approach that targets functionally important biosynthetic gene clusters (BGCs). All 45 genomes that were mined, representing Rothia mucilaginosa , Rothia dentocariosa , and Rothia aeria , harbored a catechol-siderophore-like BGC. To explore siderophore production further, we grew the previously characterized R. mucilaginosa ATCC 25296 in liquid cultures, amended with glycerol, which led to the identification of the archetype siderophore enterobactin by using tandem liquid chromatography-mass spectrometry (LC-MS/MS), high-performance liquid chromatography (HPLC), and nuclear magnetic resonance (NMR) spectroscopy. Normally attributed to pathogenic gut bacteria, R. mucilaginosa is the first commensal oral bacterium found to produce enterobactin. Cocultivation studies including R. mucilaginosa or purified enterobactin revealed that enterobactin reduced growth of certain strains of cariogenic Streptococcus mutans and pathogenic strains of Staphylococcus aureus . Commensal oral bacteria were either unaffected, reduced in growth, or induced to grow adjacent to enterobactin-producing R. mucilaginosa or the pure compound. Taken together with Rothia ’s known capacity to ferment a variety of carbohydrates and amino acids, our findings of enterobactin production add an additional level of explanation to R. mucilaginosa ’s prevalence in the oral cavity. Enterobactin is the strongest Fe(III) binding siderophore known, and its role in oral health requires further investigation. IMPORTANCE The communication language of the human oral microbiota is vastly underexplored. However, a few studies have shown that specialized small molecules encoded by BGCs have critical roles such as in colonization resistance against pathogens and quorum sensing. Here, by using a genome mining approach in combination with compound screening of growth cultures, we identified that the commensal oral community member R. mucilaginosa harbors a catecholate-siderophore BGC, which is responsible for the biosynthesis of enterobactin. The iron-scavenging role of enterobactin is known to have positive effects on the host’s iron pool and negative effects on host immune function; however, its role in oral health remains unexplored. R. mucilaginosa was previously identified as an abundant community member in cystic fibrosis, where bacterial iron cycling plays a major role in virulence development. With respect to iron’s broad biological importance, iron-chelating enterobactin may explain R. mucilaginosa ’s colonization success in both health and disease.

Background: Rothia mucilaginosa is appearing as an alarming pathogen for respiratory tract infection, infection of prosthetic devices and endocarditis. Over the past few years, Rothia sp. are frequently identified in a tertiary hospital of northern Bangladesh. Biochemical properties and antibiotic susceptibility pattern of the isolates were determined. Methods: A total 22 isolates of R. mucilaginosa were studied to observe the fermentation status of carbohydrate and protein substrates for identification by using BD Phoenix M50 system. Antibiotic susceptibility was tested by disk diffusion method. Results: All isolates of R. mucilaginosa showed variable reaction to almost 50% of the carbohydrate and around 50% of protein- amino acid substrates used. Amikacin, meropenem, imipenem and moxifloxacin showed maximum sensitivity in vitro. Conclusion: Biochemical characteristics of R. mucilaginosa can reveal the vital information necessary for accurately identifying the organism within a sample. This depends on production of various enzymes by the organism. Antibiotic susceptibility test is essential for proper management of patient. Bangladesh Journal of Medical Science Vol. 22 No. 04 October’23 Page : 827-832