EnrichmentPCRTM testing platform is the most sensitive diagnostic test available for the detection of active Bartonella species infection.
Bartonella species are difficult or, in many cases, impossible to, detect using traditional detection methods, including microbiological diagnosis by bacterial isolation, serological testing for antibodies, and conventional or real-time PCR (polymerase chain reaction). Bartonella are highly fastidious (difficult to isolate) and exhibit characteristically slow growth in cell culture or on a blood agar plate. The bacteria are also intracellular with unique immune-evasive properties which contribute to the low sensitivity of serological tests for the detection of antibodies.
Despite the exceptional sensitivity of conventional or real-time PCR, extremely low level infections can be missed. This problem can been solved with the pre-enrichment growth of bacteria following inoculation of prepared samples (blood, prepared tissue, and other fluids) into a liquid-based insect tissue culture growth medium – Bartonella Alpha Proteobacteria Growth Medium (BAPGM, pronounced bap-gee-em). This medium supports the growth of many Bartonella species and facilitates the detection and isolation of Bartonella spp. in 7 days rather than 7 weeks. BAPGM provides the ideal growth environment for these fastidious, insect-borne pathogens.
BAPGM was envisioned, refined and patented by research scientists at the North Carolina State University College of Veterinary Medicine’s Vector Borne Disease Diagnostics Laboratory as a result of ongoing efforts to enhance the growth of these highly fastidious bacteria from animal and human patient samples. Conventional PCR testing is largely ineffective at detecting the presence of Bartonella spp. infection, especially in immunocompetent patients. NCSU-CVM research scientists were able to overcome the low detectability problem by combining a BAPGM enrichment culture step with a highly sensitive PCR testing.
As Bartonella species have a dividing time of approximately 24 hours, a diagnostic sample that contains one bacterium will contain only 2 after 24 hours, 4 after 48 hours, 8 after 72 hours, etc. On a practical basis, this means that time (at least 7-10 days) is required to increase the number of bacteria in the patient’s BAPGM culture to a level in which there is enough DNA to be detected by PCR. Our research indicates that use of the BAPGM pre-enrichment culture increases the diagnostic sensitivity of Bartonella species detection by more than 400% when compared to direct extraction and PCR amplification from a patient blood sample.
Below is a short list of references regarding the analytic validity and clinical utility of the combined use of BAPGM enrichment media with PCR for the detection of Bartonella bacteria. Additional information can be found on PubMed and WebMD.
More Information
What is Bartonella?
Human Bartonellosis: Perspectives of a Veterinary Internist
Persistent Blood-Borne Infections
Molecular Diagnosis of Infections Disease
BAPGM Test Method References
Key Bartonella References