A Rare Case of Infective Endocarditis Caused by Gemella haemolysans

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.

Site-specialization of human oral Gemella species

Gemella species are core members of the human oral microbiome in healthy subjects and are regarded as commensals, although they can cause opportunistic infections. Our objective was to evaluate the site-specialization of Gemella species among various habitats within the mouth by combining pangenomics and metagenomics. With pangenomics, we identified genome relationships and categorized genes as core and accessory to each species. With metagenomics, we identified the primary oral habitat of individual genomes. Our results establish that the genomes of three species, G. haemolysans, G. sanguinis and G. morbillorum, are abundant and prevalent in human mouths at different oral sites: G. haemolysans on buccal mucosa and keratinized gingiva; G. sanguinis on tongue dorsum, throat, and tonsils; and G. morbillorum in dental plaque. The gene-level basis of site-specificity was investigated by identifying genes that were core to Gemella genomes at a specific oral site but absent from other Gemella genomes. The riboflavin biosynthesis pathway was present in G. haemolysans genomes associated with buccal mucosa but absent from the rest of the genomes. Overall, metapangenomics show that Gemella species have clear ecological preferences in the oral cavity of healthy humans and provides an approach to identifying gene-level drivers of site specificity.

<i>Gemella hemolysans</i> endocarditis and septicemia: case report and literature review

A suggestive report of Gemella hemolysans endocarditis and sepsis is described and commented on the ground of an updated literature review.

Presence of Contagious Bacterial Flora in Formalin-Fixed Cadavers: A Potential Health Hazard to Medical Professionals

Cadaveric dissection is the most important learning tool in anatomy. Although many new modalities are coming up for learning anatomy, cadaveric dissection outstands all of these as it helps students to visualize the human body and remains the most realistic way of learning anatomy. The cadavers are preserved using formalin, a potent disinfectant. Even after embalming in 5-10% formalin, the cadaver might still be infectious while using it in the dissection hall (anatomy department). Numerous bacterial species and infectious pathogens might still be seen despite using fixative agents. Several disease-causing agents may remain viable. Earlier reports suggest that there are cases where students and the working staff got infected by HIV, viral hepatitis, tuberculosis, and prion diseases. The main objective of this study is to determine if bacterial species could be recovered from cadavers that are formalin-fixed. Specific regions in the body such as the axilla, perineum, finger clefts, and oral and nasal cavities were chosen for microbiological examination to detect bacterial species. The presence of skin folds in these regions makes them potential sites for the growth of bacteria. Formalin-fixed cadavers can still act as regions for the growth of viable bacteria that can be pathogenic and affect the health of students and anatomists handling them. Proper care should be taken regarding this because students and anatomists working with these cadavers may get exposed to pathogenic organisms which may become harmful or sometimes life-threatening. Some precautions for proper dissemination of cadavers should be taken to provide a complete, safe, and healthy ambiance in the dissection hall.

A Rare Case of Gemella haemolysans Infection of Knee Arthroplasty

Gemella haemolysans is a facultative, catalase-negative, anaerobic, gram-positive cocci. It is known to mostly cause endocarditis, meningitis, peritonitis, and cerebral abscesses. However, it is extremely rare for this organism to cause infections of an orthopedic nature, with only a single report of infection in total knee arthroplasty (TKA). We present a rare case of knee arthroplasty infection caused by G. haemolysans four years after an uncomplicated TKA procedure.

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.