Several forms of Bartonella infection have been described in the literature, the most important being cat-scratch disease, endocarditis, bacillary angiomatosis, and trench fever. Vectors and modes of acquisition depend on the underlying bacterial subtype. The diagnosis relies on clinical findings and use of various tests to confirm Bartonella as the causative agent, primarily serologic and molecular methods, such as polymerase chain reaction.
The clinical presentation of Bartonella infection is diverse, as different Bartonella species are responsible for several distinct illnesses     :
The diagnosis of Bartonella infection may not be easy to attain without an extensive clinical and laboratory workup. For this reason, a detailed patient history and a thorough physical assessment are of essential importance in raising clinical suspicion. Preexisting infections and comorbidities (particularly immunosuppressive states and valvular heart disease), recent travel to South America, socioeconomic status, and close contact with cats, should be covered during history taking. On the other hand, physical findings could be even more persuading in pursuing a diagnosis of Bartonella infection, particularly in the setting of characteristic nodules or lymphadenopathy.
Laboratory studies, however, are the cornerstone in confirming the disease. Identification of specific IgM or IgG antibody titers through serologic testing is considered to be the optimal test, but antibody testing is not able to discriminate between different species of Bartonella  . Blood cultures are, by some authors, a very reliable method, but problematic details such as a very long procedure time reduce its use in general practice  . The introduction of molecular methods, mainly polymerase chain reaction (PCR), has greatly improved the overall diagnosis of bacterial infections, and they are highly recommended in the setting of Bartonella infections, as they can identify the exact species responsible for the infection   .