Bartonella Infection Linked with Rheumatoid Illnesses

A bacterium historically associated with cat scratch fever and transmitted predominately by fleas may also play a role in human rheumatoid illnesses such as arthritis.

Antibody assays and polymerase chain reaction tests (PCR), applied to DNA from growth medium enrichment culture, have been used to identify Bartonella species in patients suffering from rheumatoid diseases.

Scientists from North Carolina State University (Raleigh, NC, USA) enrolled patients examined by a rheumatologist in the Maryland–Washington DC, USA, area from August 25, 2008, through April 1, 2009. The patients had previously been diagnosed with conditions ranging from Lyme disease to arthritis to chronic fatigue. The age range of the 296 patients was 3 to 90 years; the median ages were 46 years for women who made up about 70% of the study population and 36 years for men. Blood samples were taken from the patients and analyzed by immunofluorescence antibody assay (IFA). Each sample was tested by PCR amplification of Bartonella species DNA before and after enrichment of blood and serum in Bartonella alpha proteobacteria growth medium enrichment culture.

Of the 296 patients, 62% had Bartonella antibodies, which supported prior exposure to these bacteria. Bacterial DNA was found in 41% of patient samples, allowing investigators to narrow the species of Bartonella present, with B. henselae, B. koehlerae, and B. vinsonii subsp. berkhoffii the most prevalent. B. henselae bacteremia was significantly associated with prior referral to a neurologist, most often for blurred vision, subcortical neurologic deficits, or numbness in the extremities, whereas B. koehlerae bacteremia was associated with examination by an infectious disease physician.

Bartonella is a bacterium that is maintained in nature by fleas, ticks and other biting insects. It can be transmitted to humans both by these parasites as well as by bites or scratches from infected cats and dogs. The most commonly known Bartonella-related illness is cat scratch disease, caused by B. henselae, which can be carried in a cat's blood for months to years. The fluorescein conjugated goat anti-human immunoglobulon G (IgG) used in the study was supplied by Pierce Antibody (Thermo Fisher Scientific; Rockford, IL, USA).

Edward Breitschwerdt DVM, the lead author of the study, said, "Based upon this one study we can't definitively say that a subset of rheumatoid illnesses have an infectious origin. However, our results thus far do implicate Bartonella as a factor in at least some cases. If the link between Bartonella and rheumatoid illnesses is valid, it may also open up more directed treatment options for patients with rheumatoid illnesses." The study was published online in the May 2012 issue of the journal Emerging Infectious Diseases.

Related Links:
North Carolina State University
Pierce Antibody