Search Results (216)

Schaalia canis is a Gram-positive, facultatively anaerobic, rod-shaped bacterium originally isolated from the mucosa and skin of dogs. While it is a part of the normal canine oral flora, it has rarely been implicated in human disease, with only one prior case of cellulitis reported following a dog bite. Case Presentation: We present the case of a 57-year-old immunocompetent man who developed osteomyelitis of the left index finger following a delayed presentation after a dog bite. Despite initial conservative management with empirical oral antibiotics, the infection progressed, eventually requiring surgical debridement and the terminalisation of the finger at the proximal interphalangeal joint. Cultures from intraoperative bone specimens yielded the growth of Schaalia canis, with no other pathogenic organisms identified on the extended culture. Conclusions: This is the first documented case of Schaalia canis-associated osteomyelitis in a human and the first to necessitate a surgical intervention, expanding the known clinical spectrum of this organism. This case underscores the risks of delayed intervention in polymicrobial animal bite wounds and highlights the emerging role of Schaalia species as opportunistic zoonotic pathogens, particularly in the setting of deep, refractory infections. Full article

Periodontal diseases in pediatric subjects represent a challenging and relatively underexplored area compared to the extensive data available about periodontal diseases in adults. The present narrative review aims to explore the periodontal status and the related subgingival and/or salivary microbial profiles in pediatric subjects (≤18 years), focusing also on the state of health or systemic diseases. In healthy periodontium, early colonizers, such as Streptococcus and Actinomyces spp., dominate the subgingival microbiota, supporting an eubiosis state. Low levels of Candida albicans and latent Herpesviridae may be detected. In gingivitis, the microbial profile shifts towards more pathogenic species, including Prevotella intermedia and Fusobacterium nucleatum. In necrotizing gingivitis, typically affecting systemically compromised children, the microbial profile is characterized by spirochetes, Fusobacterium, and Prevotella intermedia. Viral coinfections—especially with HSV, CMV, and EBV—are more frequently detected. In periodontitis, the microbiota was dominated by red complex pathogens along with Aggregatibacter actinomycetemcomitans in the aggressive forms, especially in systemically compromised children, as Herpesviridae reactivation and co-infections. Fungal involvement is less well characterized; Candida albicans may be present, particularly in cases of severe immune suppression. Nevertheless, the lack of pediatric longitudinal studies investigating periodontal disease progression after periodontal treatment and related changes in microbiological composition limited the understanding and exploration of the oral microbiota over time. Full article

Currently, due to the complexity of obtaining samples, specific features of laboratory processing and analysis of the results, there is a lack of data on the microbial signature of the small intestine in healthy and diseased states of the upper gastrointestinal tract. Objective: To investigate the characteristics of the small intestinal microbiome in acute pancreatitis of varying severity and to identify correlations with clinical factors. Methods: This study included 30 patients with acute pancreatitis of varying severity treated between 1 January 2019 and 31 December 2021. The composition of the microbiota was analyzed by metagenomic sequencing of the 16S rRNA gene from jejunal samples. Results: The mortality rate in the study group was 23.3%. The small intestinal microbiome was dominated by Streptococcus (median relative abundance 19.2%, interquartile range 6.4–35.1%), Veillonella (3.4%; 0.6–7%), Granulicatella (2.7%; 0.6–5%), Fusobacterium (2.2%; 0.3–5.9%), Prevotella (1.5%; 0.3–8%), Haemophilus (0.9%; 0.2–10%), Gemella (0.8%; 0.2–4.3%), and Lactobacillus (0.2%; 0.1–0.9%). More severe disease was associated with decreased abundance of Neisseria mucosa, Parvimonas micra, and Megasphaera micronuciformis. In contrast, the relative abundance of the genera Streptococcus (species S. rubneri/parasanguinis/australis), Actinomyces, and several genera within the family Enterobacteriaceae was higher in these patients. Conclusions: The state of the microbiota has important prognostic value and correlates with the duration from the onset of the pain syndrome to the time of receiving qualified care in the hospital. Full article

Background/Objectives: The formation of oral biofilms in periodontal pockets and around dental implants with induction of periodontitis or peri-implantitis is an increasing problem in dental health. The intelligent design of a biofilm makes the bacteria embedded in the biofilm matrix highly tolerant to antiseptic therapy, often resulting in tooth or implant loss. The question therefore arises as to which mouthwashes have eradication potential against oral biofilm. Methods: A human oral biofilm model was developed based on donated blood plasma combined with buffy coats, inoculated with oral pathogenic bacterial species found in periodontal disease (Actinomyces naeslundii, Fusobacterium nucleatum, Streptococcus mitis, and Porphyromonas gingivalis). Over a span of 7 days, we tested different mouth rinsing and antiseptic solutions (Chlorhexidine, Listerine^®, NaOCl, Octenisept^®, and Octenident^®) covering the matured biofilm with 24 h renewal. Phosphate-buffered saline (PBS) was used as a control. Bacterial growth patterns were detected via quantitative polymerase chain reaction (qPCR) after 2, 4, and 7 days of treatment. Results: While all groups showed initial bacterial reduction, the control group demonstrated strong regrowth from day 2 to 4. Listerine showed a near-significant trend toward bacterial suppression. Additionally, strain-specific efficacy was observed, with Octenisept^® being most effective against Streptococcus mitis, Octenident^® and NaOCl showing superior suppression of Actinomyces naeslundii, and Listerine^® outperforming other solutions in reducing Fusobacterium nucleatum. Donor-specific, individual variability further influenced treatment outcomes, with distinct trends in bacterial suppression and regrowth observed across donors. Conclusions: These findings underscore the complexity of biofilm-associated infections and highlight the importance of targeted therapeutic approaches for managing bacterial biofilms. In this experiment, the donor-specific outcomes of the antimicrobial effects of the solutions may indicate that genetic predisposition/tolerance to oral infections appears to play a critical role in the control of oral biofilms. Full article

Declining kidney function contributes to the accumulation of uraemic toxins produced by gut microbiota, leading to the uraemic syndrome. This study aimed to identify associations between uraemic toxins, diet quality, symptoms and the gut microbiota in individuals initiating peritoneal dialysis. A cross-sectional analysis of baseline data from participants in a longitudinal study was conducted. Symptom scores using the Integrated Palliative Care Outcomes Scale-Renal were recorded. Plasma p-Cresyl sulfate, indoxyl sulfate and trimethylamine N-oxide were measured using liquid chromatography-mass spectrometry. Gut microbiota was determined using 16S rRNA sequencing. Multivariate linear models examined associations across the cohort. Data from 43 participants (mean age 61 ± 13 years; 70% male; median eGFR 7 mL/min/1.73 m²) were analysed. Diabetes was the primary cause of kidney disease (51.2%). Patients were classified into ‘high’ (n = 18) and ‘low’ (n = 26) uraemic toxin groups using K-means clustering. The ‘high’ group had a lower eGFR (p < 0.05) but no differences in diet quality or symptom scores. Significant differences in alpha and beta diversity were observed between the groups (p = 0.01). The ‘high’ group had increased Catenibacterium, Prevotella, Clostridia, and decreased Ruminococcus gnavus abundances. Multivariate models identified 32 genera associated with uraemic toxins, including positive associations of Oscillospiraceae UCG-002 and UCG-005 with p-cresyl sulfate, and negative associations with Actinomyces and Enterococcus. Patients with kidney failure initiating peritoneal dialysis have distinct uraemic toxin profiles, associated with differences in microbial diversity. This phenotype was also associated with differences in residual kidney function but not with diet or symptom severity. Longitudinal studies are required to determine causality and guide therapeutic interventions. Full article

Background: Halitosis is frequently observed in patients undergoing orthodontic treatment with multibracket appliances, primarily due to volatile sulfur compounds (VSCs) produced by oral anaerobic bacteria. Cetylpyridinium chloride (CPC) is a widely used antimicrobial agent in oral care products and may help alleviate halitosis.This study aimed to evaluate the effects of 0.05% CPC mouthwash on halitosis, oral hygiene indices, and the tongue microbiota in orthodontic patients with elevated VSC levels. Methods: In this randomized, double-blind, placebo-controlled clinical trial, 30 orthodontic patients with elevated VSCs (≥150 ppb) were assigned to a CPC mouthwash group or a placebo group. Participants used the assigned mouthwash three times daily for 1 month. Halitosis was quantitatively assessed by gas chromatography (Oral Chroma™), and oral hygiene parameters including Plaque Index (PI), Gingival Index (GI), Tongue Coating Index (TCI), and unstimulated salivary flow rate were evaluated at baseline and after the intervention. The tongue microbiota was analyzed by 16S rRNA sequencing. Results: The CPC mouthwash group showed significant reductions in total VSCs, hydrogen sulfide, methyl mercaptan, PI, GI, and TCI (p < 0.05), while salivary flow rate and dimethyl sulfide remained unchanged. Microbiome analysis revealed decreases in halitosis-associated genera (Actinomyces, Corynebacterium, Tannerella) and increases in beneficial species such as Streptococcus salivarius. Conclusions: CPC mouthwash (0.05%) effectively reduced halitosis and improved oral hygiene parameters in orthodontic patients, likely through modulation of the tongue microbiota. This mouthwash may serve as a safe and practical adjunct to conventional oral hygiene practices during orthodontic treatment. Full article

Background/Objectives: This investigation evaluated 2,6-Dichlorophenolindophenol (DCIP), a redox dye, as a colorimetric reagent for rapid quantification of oral bacteria and examined the antimicrobial effects of oral hygiene formulations. Methods/Results: Viable microbial cells reduce DCIP, resulting in a loss of its blue color which can be measured spectrophotometrically. Strains of Actinomyces viscosus, Veillonella atypica, Aggregatibacter actinomycetemcomitans, Streptococcus mutans and Candida albicans grown in the laboratory reduced DCIP. Significant correlations between increasing viable plate counts and DCIP reduction were noted for strains of oral organisms. Intact microbial cells reduced DCIP, with insignificant reductions observed by spent microbial media or bacteria free culture media. Organisms inactivated by either heat or cold demonstrated significantly lower DCIP reduction in comparison to metabolically intact organisms grown under optimal conditions. Conclusions: DCIP reduction provided a rapid and accurate method to evaluate antimicrobial effects of clinical proven mouthwashes formulated with cetylpyridinium chloride or chlorhexidine and toothpastes for a range of oral bacteria. Together, these results identify a rapid, low-cost method using common laboratory equipment to enumerate oral organisms with a visual outcome. Full article

Background/Objectives: Over the past two decades, the incidence of early-onset colorectal cancer (EoCRC) has been increasing, although its underlying causes remain unclear. Gut microbiome is known to play a role in carcinogenesis of colorectal cancer. This scoping review aims to systematically map and synthetize current evidence on gut microbiome characterization in EoCRC (vs. late-onset colorectal cancer (LoCRC) and healthy individuals), describe the methodology used, and identify knowledge gaps to inform and guide future research. Methods: This systematic scoping review followed the Joanna Briggs Institute (JBI) methodology for scoping reviews. Searches were conducted in PubMed, Web of Science, and Scopus between January and February 2025. Two reviewers independently screened and selected the studies. One reviewer extracted the relevant information, using an adapted version of the JBI template. Results: Seven studies met eligibility criteria. Compared to healthy young adults, EoCRC patients had a predominance of lower α diversity, different β diversity, and greater abundance of Flavonifractor plautii, Akkermansia muciniphila, Bacteroides, and Fusobacteria. Comparisons with LoCRC showed that EoCRC had distinct β diversity and a higher abundance in Fusobacterium, Akkermansia, Bacteroides, and Actinomyces. Only three studies correlated the microbiota composition of EoCRC with clinicopathology features and suggested positive associations between Fusobacterium abundance, rectal tumors and lower survival and Akkermansia abundance with body mass index (BMI) ≥ 25 kg/m², rectal EoCRC, and better survival. Conclusions: There is a lack of large, methodologically robust studies linking gut microbiota with clinicopathological, lifestyle, and tumor molecular features in EoCRC. Our review highlights critical knowledge gaps, the need for standardized methodologies, and key areas for future investigation. Full article

Groundwater harbors phylogenetically diverse Candidate Phyla Radiation (CPR) bacteria, representing an ideal ecosystem for studying this microbial dark matter. However, no CPR strains have been successfully isolated from groundwater, severely limiting further research. This study employed a multi-metagenome approach, integrating time-resolved sampling, antibiotic/nutrient interventions, and microbial correlation networks to unravel CPR ecological roles in groundwater and provide insights into their subsequent cultivation. Through 36 metagenomes from a groundwater system containing at least 68 CPR phyla, we revealed the time-sensitive collapse of CPR communities: total abundance plummeted from 7.9% to 0.15% within 48 h post-sampling, driven by competition with rapidly dividing non-CPR bacteria, such as members of Pseudomonadota. Ampicillin (100 mg/L) stabilized CPR communities by suppressing competitors, whereas low-nutrient conditions paradoxically reversed this effect. Long-term enrichment (14 months) recovered 63 CPR phyla (0.35% abundance), revealing their survival resilience despite nutrient deprivation. Correlation networks prioritized Actinomyces, a novel Acidimicrobiaceae genus, Aestuariivirga, Baekduia and Caedimonadaceae as potential CPR partners, providing actionable targets for co-culture trials. Here, we propose actionable recommendations spanning groundwater sampling, activation status, identification of CPR symbiotic partners, and optimization of culture conditions, which bypass traditional blind cultivation and are critical for future efforts to cultivate CPR bacterial strains from groundwater. Cultivating CPR bacteria will contribute to clarifying their diversity, ecological roles, evolutionary mechanisms, metabolic pathways, and genetic potential. Full article

Medication-related osteonecrosis of the jaw (MRONJ) is a multifactorial condition defined as an adverse drug reaction that results in progressive jawbone destruction and necrosis in individuals treated with certain medications, occurring without a history of prior radiotherapy. These drugs are mainly bisphosphonates, denosumab, and other bone-modifying agents, anti-angiogenic agents such as anti-endothelial growth factor, tyrosine kinase inhibitors, and proteins classified as mammalian targets of rapamycin. The diagnosis of MRONJ is based on clinical (exposed jawbone, fistula with pus, hyperplasia of the mucosa overlying the necrotic bone tissue) and radiological evaluation. We report four cases of clinical and radiological evidence of osteonecrosis of the jaw that are unrelated to the use of antiresorptive or anti-angiogenic agents. In two instances, histological and microbiological evidence was also found (high concentration of Actinomyces, the microbe most commonly found in oral sites affected by MRONJ). These atypical cases are reported to highlight the possibility that other, previously undocumented, drugs may also contribute to the development of ONJ Full article

Background/Objective: Actinomyces is a genus of anaerobic gram-positive bacteria. It forms part of human body microbiota commonly in the oral cavity and genital tract. During pregnancy, the organism may cause the rare chorioamnionitis, where the maternal genital tract or other sites such as the oral cavity will be the likely source of the pathogen. This condition may increase the risk of foetal morbidity and mortality, and preterm birth. Methods: The placenta of a 33-year-female, primigravida, who presented with preterm labour and eventual delivery of baby at 20 weeks gestation was sent for histopathological examination. Her antenatal and clinical history were reviewed, to identify possible aetiology for her preterm birth. Results: She is noted to have presented with sudden per-vaginal creamy coloured discharge with no associated odour and no irritation. The discharge became blood staining associated with labour pain, this followed by premature spontaneous rupture of membrane and pre-mature labour. Laboratory tests revealed leucocytosis, neutrophilia, monocytosis, high CRP and elevated derived fibrinogen. The patient was delivered of a live male baby weighing 0.35 kg, who died shortly after birth. Placenta microscopic examination revealed patchy severe acute chorioamnionitis and prominent clusters of Gram-positive filamentous bacteria with histopathologic features of Actinomyces spp. The mother before discharged was treated with oral antibiotic. Conclusions: The intrauterine Actinomyces spp. infection is associated with preterm birth and neonatal mortality, early diagnosis during ante-natal could perhaps prevent preterm birth and reduce the associated neonatal mortality. Full article

Actinomycosis is a chronic suppurative granulomatous disease caused by Actinomyces spp. Although cutaneous actinomycosis is rare, dermatologists must consider it due to its potential coexistence with other pathogens, often as part of polymicrobial infections. We present a rare case of primary axillary cutaneous actinomycosis in a young woman, likely triggered by cosmetic axillary hair removal and home shaving practices. Histological examination revealed characteristics of actinomycosis, including sulfur granules and Gram-positive filamentous structures. Bacterial cultures failed to isolate Actinomyces, but identified Staphylococcus epidermidis, S. aureus (MRSA), and Corynebacterium simulans, suggesting a polymicrobial infection contributing to the inflammatory response. Molecular analysis of DNA extracted from formalin-fixed paraffin-embedded (FFPE) tissue yielded a 675 bp PCR product using Actinomyces-specific primers. BLAST analysis confirmed the species as A. gerencseriae, establishing the diagnosis of actinomycosis. However, a 1000 bp PCR product obtained using universal 16S rDNA primers could not be sequenced successfully, likely due to the presence of multiple bacterial species. Notably, Actinomyces was detected only through molecular methods, while bacterial cultures identified the aforementioned bacteria. This discrepancy between FFPE-PCR results and bacterial culture findings demonstrates a key challenge in the microbiological diagnosis of polymicrobial infections. This case highlights the importance of integrating histopathological, microbiological, and molecular techniques for accurate pathogen identification in polymicrobial infections. The failure to detect Actinomyces in bacterial cultures, despite its presence in FFPE-PCR, suggests that conventional culture methods alone may be insufficient for diagnosing such infections. Extended culture durations, selective anaerobic culture techniques, and molecular diagnostic methods are essential for a comprehensive evaluation. Recognizing Actinomyces as more than a contaminant is important for timely diagnosis and effective treatment. Increased awareness of its potential involvement in polymicrobial infection should improve clinical outcomes. Full article

Background/Objectives: Primary gastric actinomycosis is extremely rare and only a limited number of cases are published in the literature. Actinomycosis is caused by anaerobic Gram-positive bacteria; these microorganisms are members of the normal human microbiome and occasionally lead to infection, especially in immunocompromised patients or patients subjected to abdominal surgery. Advances in personalized medicine, including tailored antimicrobial therapy based on individual patient profiles, may enhance treatment efficacy and reduce unnecessary interventions. Methods: A review was performed through a literature search of the PubMed/MedLine and Scopus databases. Results: A total of 27 patients were included, 15 males (55.56%) and 12 (44.44%) females, with a mean age of 55.11 ± 17.48 years. Among the included patients, 25.93% had a history of abdominal surgery. Abdominal pain (73.08%), weight loss (40.74%), nausea or vomiting (30.77%) and fever (19.23%) constitute the most commonly reported clinical manifestations. Endoscopy (59.26%), computed tomography (48.15%), ultrasonography (22.22%) and magnetic resonance imaging (11.11%) assisted in indicating the primary lesion. Diagnosis was achieved preoperatively in 66.66% of patients, via endoscopy and biopsy (51.85%) or via cultures (14.81%), while nine cases (33.33%) were diagnosed postoperatively. The therapeutic approaches included antimicrobial administration (32%), surgery (24%) or both (44%). The most widely used antimicrobial was penicillin (77.78%) and the mean duration of antimicrobial treatment was 5.85 months. The protocol for this review was registered in Prospero (ID:CRD42025649532). Conclusions: Due to the divergent clinical presentation of primary gastric actinomycosis, clinicians should be aware of this rare entity in order to establish diagnosis in a timely manner and provide prompt and effective treatment. Full article

Endocyn is a root canal irrigant with a stable formulation of hypochlorous acid (HOCl), and should have significant antimicrobial effects. However, there are no available studies that evaluate these effects on different types of bacterial species. In this prospective in vitro study, bacterial species were grown with and without the addition of Endocyn to measure the effects on the Gram-positive bacteria Actinomyces naeslundii, Lactobacillus acidophilus, Streptococcus gordonii, and Streptococcus mutans, as well as the Gram-negative bacteria Porphyromonas gingivalis, Fusobacterium nucleatum, and Veillonella parvula. Turbidity was measured at 24 h, and the differences between the baseline and experimental treatments were measured using two-tailed Student’s t-tests and verified using ANOVA. Gram-positive bacteria were inhibited in the range of −8.2% to −35.5%, p = 0.14 to p = 0.004, while Gram-negative bacteria were inhibited in the range of −16.7% to −41.4%, p = 0.04 to p = 0.001, which were similar to the effects of 5% NaOCl (bleach). These data demonstrated that Gram-positive bacteria were somewhat resistant to Endocyn at lower levels but were inhibited at all higher concentrations, while Gram-negative bacteria were susceptible to Endocyn at all levels, and increased at higher concentrations. These results provide clinically relevant data regarding the efficacy of this disinfectant against common oral pathogens (and commensal bacteria), and are important as they provide evidence regarding public health and the environmental safety of clinical protocols regarding endodontic hygiene. Full article

Background: Iron deficiency anemia (IDA) is a common type of anemia in children and pregnant women. The effects of iron deficiency on gut microbiota and metabolic profiles are not fully understood. Methods: Mendelian randomization (MR) analysis was conducted to explore associations among IDA, gut microbiota, and metabolites. MR analysis was conducted using computational methods, utilizing human genetic data. Data were obtained from genome-wide association studies (GWAS), with inverse-variance-weighted (IVW) as the primary method. Animal models evaluated the effects of IDA on gut microbiota and metabolic profiles. Results: IVW analysis revealed significant associations between gut microbial taxa and IDA. The genus Desulfovibrio was protective (OR = 0.85, 95% CI: 0.77–0.93, p = 0.001), while Actinomyces (OR = 1.12, 95% CI: 1.01–1.23, p = 0.025) and family XIII (OR = 1.16, 95% CI: 1.01–1.32, p = 0.035) increased IDA risk. Glycine was protective (OR = 0.95, 95% CI: 0.91–0.99, p = 0.011), whereas medium low density lipoprotein (LDL) phospholipids increased risk (OR = 1.07, 95% CI: 1.00–1.15, p = 0.040). Animal models confirmed reduced Desulfovibrio, increased Actinomyces, and altered metabolites, including amino acids and phospholipids. Conclusions: IDA significantly impacts gut microbiota and metabolic profiles, offering insights for therapeutic strategies targeting microbiota and metabolism. Full article