Serologic testing for Bartonella in Manitoba, Canada, 2010-2020: a retrospective case series

Body Louse Pathogen Surveillance among Persons Experiencing Homelessness, Canada, 2020-2021

We analyzed body lice collected from persons experiencing homelessness in Winnipeg, Manitoba, Canada, during 2020-2021 to confirm vector species and ecotype and to identify louseborne pathogens. Of 556 lice analyzed from 7 persons, 17 louse pools (218 lice) from 1 person were positive for the louseborne bacterium Bartonella quintana.

Bartonella quintana pulmonary native valve endocarditis

Bartonella quintana is a well-known cause of blood culture-negative endocarditis; however, pulmonary valve involvement is rare. The case of a 40-year-old African male who presented to the Emergency Department with chest pain, cardiac failure, and a 2-week history of fever is presented. Transoesophageal echocardiography confirmed an atrial septal defect, severe pulmonary insufficiency with large vegetations, severe mitral regurgitation due to anterior leaflet prolapse, and right ventricular dysfunction. Empirical antibiotic therapy was started, and urgent surgical intervention was decided. There were vegetations on the three pulmonary valve leaflets and the mitral valve. Closure of the atrial septal defect, mitral and tricuspid valve repair, pulmonary valve replacement with a biological prosthesis, and infundibuloplasty of the right ventricle were performed. The postoperative course was uneventful. Preoperative blood cultures were negative, and B. quintana was detected through 16S rRNA gene amplification and sequencing in mitral and pulmonary implants. Serology showed positive titers of 1/1260 for both B. quintana and B. henselae. Ceftriaxone and gentamicin were administered for 10 days, followed by oral doxycycline for 12 weeks. A one-year echocardiogram showed normal functioning of the pulmonary prosthesis and the mitral and tricuspid repair. Infection caused by B. quintana is a rare cause of endocarditis with negative blood cultures, and multivalvular and pulmonary valve involvement is exceptional.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-024-01727-4.

Bartonella quintana Endocarditis: A Systematic Review of Individual Cases

BACKGROUND

Bartonella quintana is a louse-borne bacterium that remains a neglected cause of endocarditis in low-resource settings. Our understanding of risk factors, clinical manifestations, and treatment of B. quintana endocarditis are biased by older studies from high-income countries.

METHODS

We searched Pubmed Central, Medline, Scopus, Embase, EBSCO (CABI) Global Health, Web of Science and international trial registers for articles published before March 2023 with terms related to Bartonella quintana endocarditis. We included articles containing case-level information on B. quintana endocarditis and extracted data related to patient demographics, clinical features, diagnostic testing, treatment, and outcome.

RESULTS

A total of 975 records were identified, of which 569 duplicates were removed prior to screening. In total, 84 articles were eligible for inclusion, describing a total of 167 cases. Infections were acquired in 40 different countries; 62 cases (37.1%) were acquired in low- and middle-income countries (LMICs). Disproportionately more female and pediatric patients were from LMICs. More patients presented with heart failure (n = 70/167 [41.9%]) than fever (n = 65/167 [38.9%]). Mean time from symptom onset to presentation was 5.1 months. Also, 25.7% of cases (n = 43/167) were associated with embolization, most commonly to the spleen and brain; 65.5% of antimicrobial regimens included doxycycline. The vast majority of cases underwent valve replacement surgery (n = 154/167, [98.0%]). Overall case fatality rate was 9.6% (n = 16/167).

CONCLUSIONS

B. quintana endocarditis has a global distribution, and long delays between symptom onset and presentation frequently occur. Improved clinician education and diagnostic capacity are needed to screen at-risk populations and identify infection before endocarditis develops.

Infectious Diseases Among People Experiencing Homelessness: A Systematic Review of the Literature in the United States and Canada, 2003-2022

Homelessness increases the risk of acquiring an infectious disease. We conducted a systematic review of the literature to identify quantitative data related to infectious diseases and homelessness. We searched Google Scholar, PubMed, and SCOPUS for quantitative literature published from January 2003 through December 2022 in English from the United States and Canada. We excluded literature on vaccine-preventable diseases and HIV because these diseases were recently reviewed. Of the 250 articles that met inclusion criteria, more than half were on hepatitis C virus or Mycobacterium tuberculosis. Other articles were on COVID-19, respiratory syncytial virus, Staphylococcus aureus, group A Streptococcus, mpox (formerly monkeypox), 5 sexually transmitted infections, and gastrointestinal or vectorborne pathogens. Most studies showed higher prevalence, incidence, or measures of risk for infectious diseases among people experiencing homelessness as compared with people who are housed or the general population. Although having increased published data that quantify the infectious disease risks of homelessness is encouraging, many pathogens that are known to affect people globally who are not housed have not been evaluated in the United States or Canada. Future studies should focus on additional pathogens and factors leading to a disproportionately high incidence and prevalence of infectious diseases among people experiencing homelessness.

Hidden Burden of Bartonella quintana on the African Continent: Should the Bacterial Infection Be Considered a Neglected Tropical Disease?

Bartonella quintana is a louse-borne gram-negative bacillus that remains a poorly characterized cause of bacteremia, fever, and infective endocarditis. Due to the link with pediculosis, B quintana transmission is tied to poverty, conflict, overcrowding, and inadequate water access to maintain personal hygiene. Although these risk factors may be present globally, we argue that a substantial burden of undocumented B quintana infection occurs in Africa due to the high prevalence of these risk factors. Here, we describe the neglected burden of B quintana infection, endocarditis, and vector positivity in Africa and evaluate whether B quintana meets criteria to be considered a neglected tropical disease according to the World Health Organization.

Case series of 12 Bartonella quintana endocarditis from the Southwest Indian Ocean

BACKGROUND

Bartonella spp. are fastidious bacteria frequently identified as the cause of blood culture-negative (BCN) endocarditis. However, Bartonella infections are difficult to diagnose in routine laboratory testing and their incidence is probably underestimated. We investigated the epidemiological and clinical features of Bartonella endocarditis cases diagnosed between 2009 and 2021 on Reunion Island (Southwest Indian Ocean).

METHOD

We retrospectively included all patients diagnosed with Bartonella endocarditis at Reunion Island University Hospital during this period. Endocarditis was diagnosed on the basis of microbiological findings, including serological tests (IFA) and PCR on cardiac valves, and the modified Duke criteria. We used then the multispacer typing (MST) method to genotype the available Bartonella strains.

FINDINGS

We report 12 cases of B. quintana endocarditis on Reunion Island (83.3% in men, median patient age: 32 years). All the patients originated from the Comoros archipelago. The traditional risk factors for B. quintana infection (homelessness, alcoholism, exposure to body lice) were absent in all but two of the patients, who reported head louse infestations in childhood. Previous heart disease leading to valve dysfunction was recorded in 50% of patients. All patients underwent cardiac valve surgery and antimicrobial therapy with a regimen including doxycycline. All patients presented high C-reactive protein concentrations, anemia and negative blood cultures. The titer of IgG antibodies against Bartonella sp. exceeded 1:800 in 42% of patients. Specific PCR on cardiac valves confirmed the diagnosis of B. quintana endocarditis in all patients. Genotyping by the MST method was performed on four strains detected in preserved excised valves and was contributive for three, which displayed the MST6 genotype.

CONCLUSIONS

Bartonella quintana is an important cause of infective endocarditis in the Comoros archipelago and should be suspected in patients with mitral valve dysfunction and BCN from this area.

Central retinal vein occlusion associated with Bartonella henselae infection

PURPOSE

To report the clinical features and treatment course of a case of central retinal vein occlusion (CRVO) as the initial sign of ocular Bartonella henselae (B. henselae) infection.

OBSERVATION

A 36-year-old male was evaluated for unilateral vision loss. He denied prodromal symptoms but reported prior exposure to fleas. Best corrected visual acuity (BCVA) was 20/400 in the left eye. Clinical examination revealed a CRVO with atypical features including significant peripapillary exudates and peripheral vascular sheathing. Laboratory testing revealed elevated B. henselae IgG titers (1:512) with no abnormalities on hypercoagulability testing. The patient was treated with doxycycline and aflibercept with an excellent clinical response and improvement in BCVA to 20/25 in the left eye two months later.

CONCLUSION

CRVO is a rare but sight-threatening complication of ocular bartonellosis and can be the presenting sign of infection, even in the absence of cat exposure or prodromal symptoms.