Molecular and Serological Diagnosis of Bartonella Infection in 61 Dogs from the United States

Abstract

Background: Molecular diagnosis of canine bartonellosis can be extremely challenging and often requires the use of an enrichment culture approach followed by PCR amplification of bacterial DNA.Hypotheses: (1) The use of enrichment culture with PCR will increase molecular detection of bacteremia and will expand the diversity of Bartonella species detected. (2) Serological testing for Bartonella henselae and Bartonella vinsonii subsp. berkhoffii does not correlate with documentation of bacteremia.Animals: Between 2003 and 2009, 924 samples from 663 dogs were submitted to the North Carolina State University, College of Veterinary Medicine, Vector Borne Diseases Diagnostic Laboratory for diagnostic testing with the Bartonella a-Proteobacteria growth medium (BAPGM) platform. Test results and medical records of those dogs were retrospectively reviewed.Methods: PCR amplification of Bartonella sp. DNA after extraction from patient samples was compared with PCR after BAPGM enrichment culture. Indirect immunofluorescent antibody assays, used to detect B. henselae and B. vinsonii subsp. berkhoffii antibodies, were compared with PCR.Results: Sixty-one of 663 dogs were culture positive or had Bartonella DNA detected by PCR, including B. henselae (30/61), B. vinsonii subsp. berkhoffii (17/61), Bartonella koehlerae (7/61), Bartonella volans-like (2/61), and Bartonella bovis (2/61). Coinfection with more than 1 Bartonella sp. was documented in 9/61 dogs. BAPGM culture was required for PCR detection in 32/61 cases. Only 7/19 and 4/10 infected dogs tested by IFA were B. henselae and B. vinsonii subsp. berkhoffii seroreactive, respectively.Conclusions and Clinical Importance: Dogs were most often infected with B. henselae or B. vinsonii subsp. berkhoffii based on PCR and enrichment culture, coinfection was documented, and various Bartonella species were identified. Most infected dogs did not have detectable Bartonella antibodies.

Serial Testing from a 3-Day Collection Period by Use of the Bartonella Alphaproteobacteria Growth Medium Platform May Enhance the Sensitivity of Bartonella Species Detection in Bacteremic Human Patients

“…To enhance the diagnostic documentation of infection with Bartonella spp., our laboratory has combined enrichment cultures that utilize an insect cell culture liquid growth medium, Bartonella Alphaproteobacteria growth medium (BAPGM), with highly sensitive PCR assays (7,9). When used to test blood, cerebrospinal and joint fluids, or pathological effusions from dogs or horses, PCR following enrichment culture has enhanced the diagnostic sensitivity over blood PCR testing alone (10)(11)(12)(13). We refer to this diagnostic approach as the BAPGM enrichment culture platform.…”

Bartonellosis, One Health and all creatures great and small

“…1,3 In the context of clinical diagnosis, B. henselae is the most common Bartonella species found in the blood of sick dogs using the Bartonella alpha-Proteobacteria growth medium (BAPGM) enrichment blood culture platform; however, most sick bacteraemia dogs, despite a history of chronic illness, do not have detectable B. henselae antibodies by immunofluorescent antibody testing, for reasons that remain unclear. 21 As discussed under the diagnosis section, seronegative bacteraemia may result in a substantial underestimation of Bartonella seroprevalence in animal and human studies.…”

“…Thrombocytopenia, anaemia, which can be secondary immunemediated, and neutropenia or neutrophilic leucocytosis are the haematological abnormalities reported in dogs that are Bartonella seroreactive or BAPGM enrichment blood culture/PCR positive. 3,21,47 Thrombocytopenia is found in approximately half and eosinophilia in approximately one third of infected dogs, and monocytosis frequently occurs in association with Bartonella endocarditis. 2,3 Haematological abnormalities have been rarely reported in cats, but similar to dogs, a subset of Bartonella-infected cats are neutropenic or mildly thromobocytopenic.…”

“…58,61 This medium also facilitates documentation of co-infections with more than one Bartonella species or with other bacteria. 21,[59][60][61] Obviously, the relative sensitivity of diagnostic methods used to detect Bartonella species infection greatly influences the results and interpretation of epidemiological studies, an investigator's ability to establish disease causation, or a clinician's ability to achieve a diagnosis and initiate appropriate treatment. The BAPGM platform combines enrichment culture of a clinical specimen in the liquid growth medium for a minimum of 7 days, followed by a highly sensitive PCR assay designed to amplify all known Bartonella species.…”

“…Therefore, our research found that enrichment culture of clinical specimens in an optimized, insect cell culture growth medium, prior to PCR testing, substantially increased the sensitivity of detecting infection and diagnosing bartonellosis, see below for more details. 21,49,[58][59][60][61] As with other infectious diseases, seroconversion (at least a four-fold rise in antibody titre over a 2-3 week period) can be used to confirm an acute case of bartonellosis. For reasons that remain unclear, antibody reactivity is detected in only 50% of dogs infected with B. vinsonii subsp.…”