Bicuspid aortic valve endocarditis caused by Gemella sanguinis: Case report and literature review

Bacillus siamensis Improves the Immune Status and Intestinal Health of Weaned Piglets by Improving Their Intestinal Microbiota

Previous studies on the early interference of gut microbiota by Bacillus siamensis (B. siamensis) in weaned piglets are rarely reported, and the present trial is a preliminary study. This experiment was conducted to investigate the effects of B. siamensis supplementation on the growth performance, serum biochemistry, immune response, fecal short-chain fatty acids and microbiota of weaned piglets. Sixty weaned piglets were randomly divided into a control group (CON) and a B. siamensis group (BS), which were fed a basal diet and the basal diet supplemented with 5 × 1010 CFU B. siamensis per kg, respectively. Each group had 3 replicates and 10 piglets per replicate. The trial lasted for 28 days. The results showed that B. siamensis significantly increased the serum growth hormone (GH) and insulin-like growth factor (IGF) in piglets. Compared with the CON group, the levels of serum immunoglobulin and inflammatory factors in the BS group were significantly improved. In addition, the serum concentrations of zonulin and endotoxin (ET) in the BS group were lower. The dietary addition of B. siamensis significantly increased fecal short-chain fatty acid (SCFA) levels in piglets. Notably, B. siamensis improved the microbial composition by increasing beneficial genera, including Weissella, Lachnospiraceae_NK4A136_group and Bifidobacterium, and decreasing pathogenic genera, including Pantoea, Fusobacterium and Gemella, in piglet feces. Correlation analysis showed that the benefits of dietary B. siamensis supplementation were closely related to its improved microbial composition. In summary, the addition of B. siamensis can improve the immunity function, inflammatory response, gut permeability and SCFA levels of weaned piglets, which may be achieved through the improvement of their microbiota.

An Emerging Threat: A Systematic Review of Endocarditis Caused by Gemella Species

Infective endocarditis caused by Gemella species is increasingly recognized as an emerging clinical entity. Gemella species are fastidious gram-positive cocci that are typically commensal organisms but can become opportunistic pathogens. This systematic review aimed to provide a comprehensive overview of endocarditis due to Gemella species by synthesizing existing evidence. A total of 52 case reports were identified through a rigorous search and selection process. The most prevalent causative species were G. morbillorum (46.3%) and G. haemolysans (25.9%), with a striking male predominance (79.6%). The clinical presentation was largely nonspecific, mirroring typical infective endocarditis. However, the indolent nature of the illness and fastidious growth requirements of Gemella species often led to diagnostic delays. Echocardiography, particularly transesophageal echocardiography, played a crucial role in the diagnosis, enabling the detection of valvular vegetation and the assessment of complications. Management posed significant challenges, including the need for broad-spectrum empirical antibiotic therapy and increasing antimicrobial resistance among Gemella isolates. Surgical intervention was frequently required for severe valvular dysfunction, persistent infection, or embolic complications. Despite advances in diagnosis and treatment, endocarditis due to Gemella species remains associated with significant morbidity and mortality, underscoring the importance of early recognition and multidisciplinary management. This review highlights the emerging clinical significance of Gemella species as causative agents of infective endocarditis and identifies areas for further research.

Oral microbiota and oral squamous cell carcinoma: a review of their relation and carcinogenic mechanisms

Oral Squamous Cell Carcinoma (OSCC) is the most common type of head and neck cancer worldwide. Emerging research suggests a strong association between OSCC and the oral microbiota, a diverse community of bacteria, fungi, viruses, and archaea. Pathogenic bacteria, in particular Porphyromonas gingivalis and Fusobacterium nucleatum, have been closely linked to OSCC. Moreover, certain oral fungi, such as Candida albicans, and viruses, like the human papillomavirus, have also been implicated in OSCC. Despite these findings, the precise mechanisms through which the oral microbiota influences OSCC development remain unclear and necessitate further research. This paper provides a comprehensive overview of the oral microbiota and its relationship with OSCC and discusses potential carcinogenic pathways that the oral microbiota may activate or modulate are also discussed.

Bicuspid Aortic Valve Endocarditis Caused by Streptococcus sanguinis: A Case Report

Antibiotic prophylaxis prior to dental work in bicuspid aortic valve (BAV) patients is currently a matter of debate. The American Dental Association does not require those with native BAV to receive antibiotic prophylaxis prior to dental work as BAV is considered an "intermediate" risk for infective endocarditis (IE). We present the case of a 63-year-old male, with a medical history of BAV, who acquired Streptococcus sanguinis IE after a routine dental cleaning four months prior to initial onset of symptoms. He exhibited new-onset and severe aortic regurgitation at presentation, requiring urgent aortic valve replacement to restore valve function. BAV patients are at high risk of IE, emphasizing the need for prophylactic antibiotics in dental cleaning as well as invasive dental procedures in those with BAV.

Characterization of Lung and Oral Microbiomes in Lung Cancer Patients Using Culturomics and 16S rRNA Gene Sequencing

Recently, microbiota dysbiosis in lung cancer has attracted immense attention. Studies on lung microbes are mostly based on sequencing, which has left the potentially functional bacteria with extremely low abundance uncovered. In this study, we characterized and compared the lung and oral cavity microbiotas using culturomics and 16S rRNA gene sequencing. Of the 198 bacteria identified at the species level from bronchoalveolar lavage fluid (BALF) samples, Firmicutes was predominant (39.90%). Twenty bacterial species isolated from BALF samples were present in at least half of the patients and were also highly abundant in oral samples. Of all isolated strains, Streptococcus and Veillonella were highly dominant. The abundance of Prevotella and Veillonella decreased from the oral cavity to the lung, whereas that of Pseudomonas increased. Linear discriminant analysis effect size demonstrated that Prevotella was more abundant in the healthy samples than in the cancerous ones, which is in accordance with the isolation of Prevotella oralis only from the healthy group using culturomics. Moreover, Gemella sanguinis and Streptococcus intermedius were isolated only from the non-small-cell lung cancer (NSCLC) group, and 16S rRNA gene sequencing showed that they were higher in the NSCLC than in the small-cell lung cancer group. Furthermore, while Bacillus and Castellaniella were enriched in lung adenocarcinoma, Brucella was enriched in lung squamous cell carcinoma. Overall, alterations were observed in the microbial community of patients with lung cancer, whose diversity might be site and pathology dependent. Using culturomics and 16S rRNA gene amplicon sequencing, this study has provided insights into pulmonary and oral microbiota alterations in patients with lung cancer. IMPORTANCE The relationship between lung microbiota and cancer has been explored based on DNA sequencing; however, culture-dependent approaches are indispensable for further studies on the lung microbiota. In this study, we applied a comprehensive approach combining culturomics and 16S rRNA gene amplicon sequencing to detect members of the microbiotas in saliva and BALF samples from patients with unilateral lobar masses. We found alterations in the microbial community of patients with lung cancer, whose diversity might be site and pathology dependent. These features may be potential bacterial biomarkers and new targets for lung cancer diagnosis and treatment. In addition, a lung and oral microbial biobank from lung cancer patients was established, which represents a useful resource for studies of host-microbe interactions.

Captive Breeding and Trichomonas gallinae Alter the Oral Microbiome of Bonelli's Eagle Chicks

Bonelli's eagle (Aquila fasciata) is an endangered raptor species in Europe, and trichomonosis is one of the menaces affecting chicks at nest. In this paper, we attempt to describe the oral microbiome of Bonelli's eagle nestlings and evaluate the influence of several factors, such as captivity breeding, Trichomonas gallinae infection, and the presence of lesions at the oropharynx. The core oral microbiome of Bonelli's eagle is composed of Firmicutes, Bacteroidota, Fusobacteria and Proteobacteria as the most abundant phyla, and Megamonas and Bacteroides as the most abundant genera. None of the factors analysed showed a significant influence on alfa diversity, but beta diversity was affected for some of them. Captivity breeding exerted a high influence on the composition of the oral microbiome, with significant differences in the four most abundant phyla, with a relative increase of Proteobacteria and a decrease of the other three phyla in comparison with chicks bred at nest. Some genera were more abundant in captivity bred chicks, such as Escherichia-Shigella, Enterococcus, Lactobacillus, Corynebacterium, Clostridium and Staphylococcus, while Bacteroides, Oceanivirga, Peptostreptococcus, Gemella, Veillonella, Mycoplasma, Suttonella, Alloscardovia, Varibaculum and Campylobacter were more abundant in nest raised chicks. T. gallinae infection slightly influenced the composition of the microbiome, but chicks displaying trichomonosis lesions had a higher relative abundance of Bacteroides and Gemella, being the last one an opportunistic pathogen of abscess complications in humans. Raptor's microbiomes are scarcely studied. This is the first study on the factors that influence the oral microbiome of Bonelli's eagle.

Gemella sanguinis Infective Endocarditis-Challenging Management of an 8-Year-Old with Duchenne Dystrophy and Undiagnosed Congenital Heart Disease: A Case Report

Congenital heart disease (CHD) remains a predisposing cardiac condition for infective endocarditis (IE). Case report: We present the case of 8-year-old boy with no known pre-existing cardiac disease diagnosed with infective endocarditis (IE) with Gemella sanguinis. After admission, he underwent transthoracic echocardiography (TTE), which revealed the presence of Shone syndrome with a bicuspid valve, mitral parachute valve and severe aortic coarctation. He developed a paravalvular aortic abscess with severe aortic regurgitation and left ventricle (LV) systolic dysfunction for which he required a complex surgical intervention after six weeks of antibiotic treatment, consisting of Ross operation and coarctectomy, with a complicated postoperative course, cardiac arrest and ECMO support for five days. The evolution was slow and favorable, with no significant residual valvular lesions. However, persistent LV systolic dysfunction and increased muscle enzymes required further investigation to establish a genetic diagnosis of Duchenne disease. As Gemella is not considered a frequent pathogen of IE, no current guidelines refer specifically to it. Additionally, the predisposing cardiac condition of our patient is not currently classified as "high-risk" for IE; this is not considered an indication for IE prophylaxis in the current guidelines. Conclusion: This case illustrates the importance of accurate bacteriological diagnosis in infective endocarditis and poses concerns regarding the necessity of IE prophylaxis in "moderate risk" cardiac conditions such as congenital valvular heart disease, especially aortic valve malformations.

Cryptic Oral Microbiota: What Is Its Role as Obstructive Sleep Apnea-Related Periodontal Pathogens?

Periodontitis has been commonly linked to periodontopathogens categorized in Socransky's microbial complexes; however, there is a lack of knowledge regarding "other microorganisms" or "cryptic microorganisms", which are rarely thought of as significant oral pathogens and have been neither previously categorized nor connected to illnesses in the oral cavity. This study hypothesized that these cryptic microorganisms could contribute to the modulation of oral microbiota present in health or disease (periodontitis and/or obstructive sleep apnea (OSA) patients). For this purpose, the presence and correlation among these cultivable cryptic oral microorganisms were identified, and their possible role in both conditions was determined. Data from oral samples of individuals with or without periodontitis and with or without OSA were obtained from a previous study. Demographic data, clinical oral characteristics, and genera and species of cultivable cryptic oral microorganisms identified by MALDI-TOF were recorded. The data from 75 participants were analyzed to determine the relative frequencies of cultivable cryptic microorganisms' genera and species, and microbial clusters and correlations tests were performed. According to periodontal condition, dental-biofilm-induced gingivitis in reduced periodontium and stage III periodontitis were found to have the highest diversity of cryptic microorganism species. Based on the experimental condition, these findings showed that there are genera related to disease conditions and others related to healthy conditions, with species that could be related to different chronic diseases being highlighted as periodontitis and OSA comorbidities. The cryptic microorganisms within the oral microbiota of patients with periodontitis and OSA are present as potential pathogens, promoting the development of dysbiotic microbiota and the occurrence of chronic diseases, which have been previously proposed to be common risk factors for periodontitis and OSA. Understanding the function of possible pathogens in the oral microbiota will require more research.

Aortic and Mitral Valve Infective Endocarditis Caused by Gemella sanguinis

We present a case of infective endocarditis (IE) of the aortic valve, mitral valve, and aortomitral curtain caused by Gemella sanguinis. The patient was an otherwise healthy 53-year-old male without significant risk factors for infective endocarditis in his medical history. Due to the extent of the infective endocarditis and the rapid deterioration of his clinical condition, which included respiratory failure and severe heart failure, the patient was treated with urgent surgery (a Commando operation where both the aortic and mitral valves were replaced and the aortomitral curtain was reconstructed), broad-spectrum antibiotics, and aggressive postoperative measures such as venovenous (VV) extracorporeal membrane oxygenation (ECMO). This is the first reported case where the aortic valve, mitral valve, and aortomitral curtain were affected by G. sanguinis.

First Case of Pyogenic Spondylodiscitis Caused by Gemella sanguinis

A 78-year-old man presented with back pain. Magnetic resonance imaging revealed marrow edema within the L4 and L5 vertebral bodies and a spinal epidural abscess in the spinal canal. The patient was considered to have pyogenic spondylodiscitis at the L4/L5 level. The Gram-positive cocci isolated from blood cultures were subsequently identified as Gemellasanguinis using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Symptom improvement was achieved and the infection was eradicated with conservative treatment (treatment with ceftriaxone [CTRX] and minocycline [MINO]). We report the first case of G. sanguinis-associated pyogenic spondylodiscitis. MALDI-TOF MS was useful in identifying this uncommon bacterium.

Gemella haemolysans as an emerging pathogen for bacteremia among the elderly

We report a patient of an 82-year-old woman with occult Gemella haemolysans bacteremia without a clear entry site. Gemella haemolysans is part of the normal human flora but can cause severe systemic infections such as infective endocarditis on rare occasions. In this patient, physical examination showed no localized symptoms, and a transthoracic echocardiogram showed no vegetation on the heart valves. The entry site for this pathogen was unclear. As the number of the elderly with asymptomatic infections has been increasing, clinicians should be aware of that this microorganism can cause occult bacteremia and infective endocarditis.

Multi-valvular infective endocarditis from Gemella morbillorum

Gemella morbillorum is increasingly implicated in infectious endocarditis. Our patient presented with anaemia and renal failure with evidence of infarcts and embolic disease. He was found to have endocarditis with an organism that could not speciate with standard culture methods requiring matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) for identification and susceptibilities. While involvement of mitral and aortic valves can be expected with Gemella, he had rare involvement of the pulmonic valve in a structurally normal heart. Although bacteriological cure was achieved, due to the locally destructive nature of Gemella, he ultimately required valve replacements for heart failure resolution. Workup for commonly implicated pathologies associated with G. morbillorum led to suspicion of gastrointestinal malignancy with findings of occult bleeding prompting an ongoing evaluation. With improved access to advanced diagnostics, G. morbillorum has been increasingly identified in infectious endocarditis. Given its destructive nature, it is important for clinicians to consider this organism is difficult to identify isolates.

Risk Factors and Patient Profile of Infective Endocarditis due to Gemella spp

BACKGROUND

The diagnosis of infective endocarditis is difficult, especially when it involves atypical organisms. Therefore, our study identified risk factors of infective endocarditis caused by rare pathogen, Gemella spp.

METHODS

A systematic review was conducted to investigate characteristics of endocarditis patients infected with Gemella spp. using the search term "Gemella" and "endocarditis." Case reports were gathered by searching Medline/Pubmed, Google Scholar, CINAHL, Cochrane CENTRAL, and Web of Science databases. 83 articles were selected for review.

RESULTS

Five species of Gemella were identified. Typical patients were males between 31 and 45 years of age. On admission, patients had fever, tachycardia, and normal blood pressure. Common clinical manifestation other than fever included fatigue and weakness, chills and sweating, and nausea, vomiting, diarrhea, and weight changes. One in four reported a history of congenital heart disease, and a recent oral cavity infection. Laboratory tests reveal anemia, leukocytosis, and elevated erythrocyte sedimentation in all age groups, elevated C-reactive protein is observed among adult and geriatric populations only. Mitral and aortic valves were most commonly infected by Gemella spp.. The most common Gemella spp.-susceptible antibiotics were penicillin, vancomycin, cephalosporin, macrolide, and aminoglycosides. However, antibiotic resistance was observed against penicillin, aminoglycoside, and fluoroquinolone. Antibiotic course of at least six weeks resulted in superior clinical improvements than durations under six weeks. Finally, one in two patients underwent valve replacement or repair, with common complications affecting the cardiovascular, neurological, and renal systems. Finally, death occurred in 1 in 8 patients, half of which occurred post-surgical procedure, and the majority occurring equal to or greater than 1 week from admission.

CONCLUSION

Our systematic review highlights the importance of considering rare pathogens, particularly in the presence of predisposing risk factors.

A rare case of isolated mitral valve endocarditis by Gemella sanguinis: Case report and review of the literature

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Gemella sanguinis is a very rare cause of infective endocarditis.

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Only 12 cases previously reported in the literature, only two of which involved exclusively the mitral valve.

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Usually associated with preexisting cardiac condition or oral infection/instrumentation.

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Valve replacement along with prolonged antibiotic course resulted in successful outcomes in the majority of cases.

Introduction

Gemella sanguinis is an extremely rare cause of infectious endocarditis, with only 12 cases previously reported in the literature. Here we report the third known case of isolated mitral valve endocarditis secondary to G. sanguinis.

Presentation of case

A 53-year-old man with mitral valve prolapse and history of recent dental instrumentation presented with malaise, thigh and finger pain and new pansystolic murmur. He was diagnosed with severe mitral insufficiency due to infectious endocarditis secondary to G. sanguinis. He underwent mitral valve replacement and was treated with a long course of antibiotics.

Discussion

G. sanguinis is a rare cause of infectious endocarditis with very few reported cases in the literature. In the majority of reported cases, a strategy of valve replacement along with prolonged antibiotic course results in good outcome for the patient.

Smoking and microbiome in oral, airway, gut and some systemic diseases

The human microbiome harbors a diverse array of microbes which establishes a mutually beneficial relation with the host in healthy conditions, however, the dynamic homeostasis is influenced by both host and environmental factors. Smoking contributes to modifications of the oral, lung and gut microbiome, leading to various diseases, such as periodontitis, asthma, chronic obstructive pulmonary disease, Crohn’s disease, ulcerative colitis and cancers. However, the exact causal relationship between smoking and microbiome alteration remains to be further explored.