BETTER DETECTION OF BARTONELLA SPECIES INFECTIONS
After the first isolation of B. vinsonii ssp. berkhoffii, we had difficulty isolating Bartonella species in other dogs by using culture or by detecting Bartonella DNA in patient samples by PCR testing, even though we could detect antibodies by using an immunofluorescent antibody assay.
In our laboratory, we had discussed that these bacteria seem to be happier in insects than they do in dogs, so we decided
to develop an optimized insect cell culture media to enhance the growth of Bartonella species.24,25 The insect cell culture media—Bartonella alpha Proteobacteria Growth Medium, or BAPGM (Galaxy Diagnostics,
http://www.galaxydx.com/)—combined with PCR testing now allows us to grow and detect these bacteria in animals and immunocompetent people better than
any other diagnostic test currently available.26-28
My laboratory has found that 50% of dogs and people infected with B. henselae or B. vinsonii subsp. berkhoffii do not have detectable antibodies to any of the six different Bartonella species antigens used in our testing.18,26,27 So antibody testing for Bartonella species is proving to be very insensitive.
INITIAL BAPGM RESULTS AND POTENTIAL SEQUELAE OF BARTONELLA SPECIES INFECTION
Using BAPGM, our laboratory has recently started testing people in collaboration with physicians at Duke University Medical
Center and elsewhere, as a component of an Institutional Review Board-approved research study. In the first subgroup, which
was primarily composed of veterinarians, 14 of 42 people had positive Bartonella species cultures and several had Bartonella species coinfections.26 Using a survey instrument that we developed, this group of people with occupational animal contact and vector exposure described
having headaches, insomnia, memory loss, muscle pain, and joint pain.26 Similar to our findings, physicians in Israel have generated a nice body of evidence regarding the long-term follow up of
patients with cat scratch disease29-31 and have shown that a subset of those patients later develop chronic arthritis, chronic myalgia, and chronic musculoskeletal
pain as components of their illness.
We now know that some people and some dogs can be coinfected with more than one Bartonella species, as is the case in cats that may be simultaneously infected with three hemotropic Mycoplasma species.32 It was the use of BAPGM that allowed us to culture B. quintana from a woman who had been bitten by a feral cat (although we had expected to culture B. henselae or Bartonella clarridgeiae instead). Months later, we used the BAPGM enrichment approach to culture B. quintana from the feral cat that had bitten her and another feral cat that lived on her property.17 We have also used the BAPGM platform to obtain the first DNA evidence of human infection with candidatus Bartonella melophagi,28 and CDC investigators used this approach to make the first isolates of Bartonella tamiae from febrile human patients.33
On a comparative medical basis, pericarditis can occur in people and dogs infected with Bartonella species.34-36 In severely immunocompromised people, it is well known that Bartonella causes bacillary angiomatosis and peliosis hepatis, as it does in dogs.37 For example, a dog with pancytopenia due to hypersplenism that had been immunosuppressed with prednisone and azathioprine
developed cutaneous bacillary angiomatosis and B. vinsonii subsp. berkhoffii was identified.38 In collaboration with a physician at the University of Illinois College of Medicine in Chicago, we have also recently described
infection with B. vinsonii ssp. berkhoffii in a boy with epithelioid hemangioendothelioma and in a dog with cutaneous hemangiopericytoma.39