Gemella

Gemella is a genus of Gram-positive bacteria that are part of the normal flora of the human oral cavity, upper respiratory tract, and gastrointestinal tract. The genus was first described in 1960 by Berger. The name "Gemella" is derived from the Latin word for "twin" or "paired," reflecting the characteristic appearance of these bacteria, which often occur in pairs.

Characteristics

Gemella species are facultative anaerobes, meaning they can grow in both the presence and absence of oxygen. They are non-motile and do not form spores. These bacteria are typically cocci (spherical) and can appear in pairs, short chains, or clusters. They are catalase-negative, which helps differentiate them from other Gram-positive cocci such as Staphylococcus.

Species

The genus Gemella includes several species, some of which are:

• Gemella haemolysans
• Gemella morbillorum
• Gemella sanguinis
• Gemella bergeriae

Clinical Significance

While Gemella species are generally considered part of the normal human flora, they can be opportunistic pathogens. They have been implicated in various infections, including endocarditis, bacteremia, meningitis, and osteomyelitis. Infections are more likely to occur in individuals with underlying health conditions or compromised immune systems.

Diagnosis and Treatment

Diagnosis of Gemella infections typically involves microbiological culture and molecular methods such as PCR (Polymerase Chain Reaction). Treatment usually involves antibiotics, with the choice of antibiotic depending on the specific species and its antibiotic susceptibility profile. Commonly used antibiotics include penicillin, amoxicillin, and vancomycin.

Related Pages

• Gram-positive bacteria
• Oral microbiology
• Endocarditis
• Bacteremia
• Meningitis
• Osteomyelitis