Bartonella grahamii

Species of bacterium

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Bartonella grahamii
Kingdom:
Phylum:	Proteobacteria
Class:	Alphaproteobacteria
Order:	Rhizobiales
Family:	Bartonellaceae

Bartonella grahamii is a species of bacteria within the genus Bartonella. It is a Gram-negative bacterium that is known to be a zoonotic pathogen, meaning it can be transmitted from animals to humans. B. grahamii is primarily associated with rodents, which serve as its natural reservoir hosts.

Discovery and Classification

Bartonella grahamii was first described in 1995 by Birtles et al. It was isolated from the blood of small mammals, particularly rodents, in Europe. The bacterium is named after the microbiologist David Graham, who contributed significantly to the study of Bartonella species.

Morphology and Physiology

Bartonella grahamii is a small, rod-shaped bacterium. Like other members of the genus Bartonella, it is an intracellular pathogen, meaning it can live inside the cells of its host. It is a facultative intracellular organism, capable of surviving both inside and outside host cells.

Transmission and Epidemiology

The primary hosts for B. grahamii are rodents, such as mice and voles. The bacterium is transmitted between rodents by fleas, which act as vectors. Humans can become infected through contact with infected rodents or their fleas, although human infections are relatively rare.

Pathogenicity and Clinical Significance

In humans, Bartonella grahamii has been associated with cases of neuroretinitis, an inflammation of the retina and optic nerve. However, infections are uncommon and often go undiagnosed due to the mild or nonspecific nature of symptoms. The bacterium's role in human disease is still being studied, and it is considered less pathogenic than other Bartonella species such as Bartonella henselae, the causative agent of cat scratch disease.

Diagnosis and Treatment

Diagnosis of B. grahamii infection can be challenging due to the nonspecific symptoms and the difficulty in culturing the bacterium. Serological tests and molecular methods such as polymerase chain reaction (PCR) are used to detect the presence of Bartonella DNA in clinical samples.

Treatment typically involves the use of antibiotics, although the specific regimen may vary depending on the severity of the infection and the patient's overall health.

Research and Future Directions

Ongoing research is focused on understanding the ecology of B. grahamii, its interactions with host organisms, and its potential role in human disease. Studies are also exploring the genetic diversity of the bacterium and its mechanisms of pathogenicity.

Also see

• Bartonella henselae
• Bartonella bacilliformis
• Zoonosis
• Vector (epidemiology)