Research suggests that persistent infections are drivers of inflammatory symptoms, and many organisms have been strongly linked to chronic illness. One of the more recently appreciated microbes associated with human illness is Bartonella. Although one manifestation of Bartonellosis is “cat scratch disease” (Bartonella henselae), research is now showing that a persistent Bartonella bacteremia may contribute to wide-ranging chronic symptomatology, even in those who are immunocompetent. There are now over 28 characterized Bartonella species, 12 of which have been documented as human pathogens.
Bartonella Alpha-Proteobacteria Growth Medium
Traditionally, serology and polymerase chain reaction (PCR) assays have been used to diagnose Bartonella, but false negative rates can be high. To address these shortcomings, researchers have developed a novel way to document Bartonella infection. Using Bartonella alpha-proteobacteria growth medium (BAPGM) prior to PCR testing has been shown to increase diagnostic sensitivity by at least four-fold when compared with standard PCR alone. This BAPGM-PCR testing method is called Bartonella ePCR (Galaxy Diagnostics).
Studies using this testing strategy have implicated Bartonella infection in a broad range of disorders that affect the cardiovascular, lymphatic, musculoskeletal, and central nervous systems. Patients with a history of exposure to fleas (especially cat fleas), ticks, body lice, biting flies, and animal bites and scratches appear to be at particularly high risk. Although more investigations are needed, current research suggests that symptoms of Bartonella infection may include recurring fever, headaches, insomnia, joint and muscle pain, arthropathy, myalgia, neurologic dysfunction, and vasculitis. Physical findings may include lymphadenopathy, splenomegaly, and vasoproliferative tumors, as well as splenic and hepatic granulomas.
Evolving Knowledge for Treating Bartonella
An unequivocal treatment for all Bartonella infections does not currently exist, meaning that antibiotic treatments will vary. Treatment of Bartonella infections should be based on each clinical situation, the infecting Bartonella species, and whether the disease is in the acute or the chronic form. Duration of monotherapy antibiotics can last as little as 2 weeks for some acute illnesses, but can skyrocket to 4 or more months when dual therapy is required for individuals with chronic illnesses. Unfortunately, clinical and microbiological relapse and failures are still being documented.
It’s important to advise patients to take routine precautions to avoid animal bites and scratches, as well as arthropods and insects. Testing for Bartonella infections should be considered in those who are at high risk and present with persistent, non-specific rheumatic, inflammatory, or neurologic symptoms. Bartonella infection screening should also be considered prior to instituting clinical protocols that involve immune suppression. Although the accuracy of Bartonella testing has limitations, testing techniques are emerging to further assist patient diagnosis and management.