Bartonella spp. Infections Identified by Molecular Methods, United States

Abstract

Molecular methods can enable rapid identification of Bartonella spp. infections, which are difficult to diagnose by using culture or serology. We analyzed clinical test results of PCR that targeted bacterial 16S rRNA hypervariable V1-V2 regions only or in parallel with PCR of Bartonella-specific ribC gene. We identified 430 clinical specimens infected with Bartonella spp. from 420 patients in the United States. Median patient age was 37 (range 1-79) years; 62% were male. We identified B. henselae in 77%, B. quintana in 13%, B. clarridgeiae in 1%, B. vinsonii in 1%, and B. washoensis in 1% of specimens. B. quintana was detected in 83% of cardiac specimens; B. henselae was detected in 34% of lymph node specimens. We detected novel or uncommon Bartonella spp. in 9 patients. Molecular diagnostic testing can identify Bartonella spp. infections, including uncommon and undescribed species, and might be particularly useful for patients who have culture-negative endocarditis or lymphadenitis.

Keywords: Bartonella; United States; bacteria; cat-scratch disease; endocarditis; lymphadenitis; parasites; polymerase chain reaction; vector-borne infections; zoonoses.

Figure 1

Flow diagram showing clinical specimens included in the analysis in study of Bartonella spp. infections identified by molecular methods during 2003–2021 at an academic laboratory in the United States. If a patient had multiple specimens submitted >30 days apart, only information from the first Bartonella-positive specimen was included. Clinical specimens were tested for Bartonella spp. by PCR. A total of 430 specimens from 420 patients were included in the study. BT-PCR, B. henselae and B. quintana bispecific targeted PCR; NGS-16S, next-generation sequencing of 16S rRNA amplicons; PCR-16S, PCR of 16S rRNA gene followed by Sanger sequencing–based species identification.

Figure 2

Number and percentage of specimens tested by using Bartonella-specific PCR during 2003–2021 in study of Bartonella spp. infections identified by molecular methods, United States. A total of 2,273 specimens were submitted for B. henselae and B. quintana bispecific targeted PCR. Bars indicate total numbers of submitted specimens each year and numbers of Bartonella-positive or negative specimens. Line indicates percentage of specimens that were positive for Bartonella spp.

Figure 3

Frequency of Bartonella spp. from different anatomic sites identified during 2003–2021 in study of Bartonella spp. infections identified by molecular methods, United States. Multiple specimens were submitted for 9 patients. We detected Bartonella spp. in both splenic and cardiac specimens from 1 patient, in 2 cardiac specimens each from 7 patients, and in 3 cardiac specimens from 1 patient. If we detected Bartonella spp. on multiple valve specimens, those were included in the total count for all involved valves. For the heart valve inset, other sites are cardiac tissue NOS (n = 18), right ventricular outflow tract conduit (n = 3), pacemaker or implantable cardiac device lead (n = 4), and coronary cusp (n = 1). For the lymph node inset, other sites are lymph node NOS (n = 38), supraclavicular (n = 3), submental (n = 2), mesenteric (n = 1), preauricular (n = 1), submandibular (n = 1), epitrochlear (n = 1), jugular (n = 1), iliac (n = 1), and paraspinal (n = 1). NOS, not otherwise specified.