Barnesiella ssp. is a small group of two species of bacteria that are usually only found at reasonably low levels in the gut.

The Bartonella genus (IgG) marker test is an integral component of the diagnostic panel for Bartonellosis, a group of infectious diseases caused by various species within the Bartonella genus, such as Bartonella henselae and Bartonella quintana. This serological assay is specifically designed to detect Immunoglobulin G (IgG) antibodies directed against Bartonella antigens in the patient's serum. IgG antibodies are the most abundant type of antibody found in blood circulation and are primarily responsible for long-term immunity and pathogen neutralization. The presence of IgG antibodies to Bartonella typically indicates either a past infection or a chronic, ongoing infection, as these antibodies generally develop several weeks post-infection and can persist for months or years.

Bartonellosis, a group of infectious diseases caused by bacteria of the Bartonella genus, can be diagnosed using serological panels that include the Bartonella genus (IgM) marker test. This test is designed to detect Immunoglobulin M (IgM) antibodies in the blood, which are produced by the immune system as an early response to a Bartonella infection. Bartonella species, including Bartonella henselae and Bartonella quintana, are known to cause diseases such as cat scratch disease, trench fever, and bacillary angiomatosis.

Bartonella henselae Ab, IgG is a blood test that measures the level of IgG antibodies against the bacteria Bartonella henselae, which is commonly associated with cat scratch disease. IgG antibodies are produced by the immune system as a response to a past or ongoing infection, indicating that the person has been exposed to the bacteria. A positive IgG result suggests a previous infection with Bartonella henselae and that the body has developed immunity to it, although it may also indicate a chronic or persistent infection. Typically, this test is used to help diagnose cat scratch disease, which can cause symptoms like swollen lymph nodes, fever, and fatigue, particularly in people who have had contact with cats or have been scratched or bitten by one.

Bartonella henselae Ab, IgM is a blood test marker used to detect the presence of IgM antibodies against the Bartonella henselae bacteria, which is the cause of cat scratch disease and other Bartonella-related infections. The IgM antibodies are part of the immune system's early response to an infection, and their presence usually indicates a recent or ongoing infection with Bartonella henselae. When someone has symptoms like fever, swollen lymph nodes, or a history of being scratched or bitten by a cat, this test helps diagnose Bartonella infection by confirming that the body is actively fighting the bacteria. A positive IgM result suggests a recent infection, while a negative result might indicate either no infection or a past infection where IgM antibodies have already declined.

Several species of Bartonella bacteria cause disease in people. Infection with any one of these bacteria is referred to broadly as bartonellosis, although some forms of infection also have common names (for example, cat scratch disease). 

Bartonella bacteria are spread to humans by fleas, body lice, sand flies, or contact with flea-infested animals. There is no evidence that ticks spread Bartonella infection to people. In the United States, the most common form of bartonellosis is caused by Bartonella henselae.

The Bartonella species (IgG) marker on a Bartonellosis panel plays a pivotal role in the serological diagnosis of infections caused by various Bartonella species, which include notable pathogens like Bartonella henselae and Bartonella quintana. This test specifically targets Immunoglobulin G (IgG) antibodies, which are produced by the immune system as a later response to an infection. IgG antibodies typically develop within a few weeks post-exposure and can persist for months or years, providing long-term immunity and indicating either past exposure or a chronic infection.

The Bartonella species (IgM) marker, a crucial element in the diagnostic panel for Bartonellosis, is designed to detect specific Immunoglobulin M (IgM) antibodies in the bloodstream, targeting various Bartonella species, including common pathogens like Bartonella henselae and Bartonella quintana. IgM antibodies are the initial type of antibody that the immune system produces in response to an infection. Their presence in the blood usually indicates a recent or acute infection with Bartonella, as these antibodies typically appear within a few days to a week following exposure and can remain detectable for several months thereafter.

Bartonella vinsonii, a member of the genus Bartonella, is a proteobacterium that is the causative agent of Bartonellosis. The pathogen has been isolated in immunocompetent patients with endocarditis, arthritis, neurological disease and neoplasia . From animal studies it appears that Bartonella henselae is well adapted to felines or cats while Bartonella vinsonii is well adapted to canines or dogs though each species can infect both.