Recent questions relative to the BAPGM Dx platform.
1. Does BAPGM grow other bacteria and, if so, should blood cultures be performed in both the
Clinical Microbiology Laboratory and at Galaxy Dx?
Answer: Yes, blood cultures should be performed in both laboratories. BAPGM is an optimized insect
cell culture-based medium that will grow most common pathogenic bacteria. However, the utility of
BAPGM is to detect Bartonella spp. and other difficult to isolate (i.e. fastidious) bacteria. Because the
design of the testing platform targets Bartonella specifically, (initial PCR for Bartonella directly from
blood, followed by repeat Bartonella PCR after a 10 day incubation period of the blood in the liquid
culture medium) the growth of a non-fastidious bacteria, such as Staphylococcus or Streptococcus spp.
would not be detected until a subculture onto agar was performed, which occurs after a 10 day
incubation period in the BAPGM liquid culture medium. Therefore important microbiological test
results would be delayed. When attempting to specifically isolate a Bartonella spp. from aqueous,
pleural, pericardial or cerebrospinal fluids, BAPGM enrichment culture would be recommended.
2. If infection with a Bartonella spp. is suspected, should serology be requested from the NCSUVBDDL and BAPGM blood culture (or other sample) requested from Galaxy Dx?
Answer: Yes, optimally both testing modalities should be requested. In some patients Bartonella spp.
antibodies are detectable, but the laboratory does not detect DNA or isolate the organism. This can be
true for many fastidious infectious organisms that are absent from the sample collected or are in such
low numbers that they are not detectable by PCR amplification. Alternatively, and for reasons that are
unclear, Bartonella spp. antibodies are not detected in approximately half of the dogs in which the
organism is amplified using the BAPGM platform. In addition, serology is currently performed in the
VBDDL using B. henselae and B. vinsonii subsp. berkhoffii antigens. In recent years, BAPGM has assisted
the isolation and molecular characterization of other named and unnamed Bartonella spp. Infection
with these species may or may not induce antibody responses that cross react with the current test
antigens. Bartonella henselae and B. vinsonii subsp. berkhoffii antibody titers will continue to be
reported as a component of the VBDDL Tickborne Disease serological panel or can be requested as
individual tests.