[Endocarditis due to Bartonella spp. Three new clinical cases and Spanish literature review]

Bartonella Endocarditis in Spain: Case Reports of 21 Cases

Blood culture negative endocarditis (BCNE) is frequent in infective endocarditis (IE). One of the causes of BCNE is fastidious microorganisms, such as Bartonella spp. The aim of this study was to describe the epidemiologic, clinical characteristics, management and outcomes of patients with Bartonella IE from the “Spanish Collaboration on Endocarditis-Grupo de Apoyo al Manejo de la Endocarditis infecciosa en España (GAMES)”cohort. Here we presented 21 cases of Bartonella IE. This represents 0.3% of a total of 5590 cases and 2% of the BCNE from the GAMES cohort. 62% were due to Bartonella henselae and 38% to Bartonella quintana. Cardiac failure was the main presenting form (61.5% in B. hensalae, 87.5% in B. quintana IE) and the aortic valve was affected in 85% of the cases (76% in B. henselae, 100% in B. quintana IE). Typical signs such as fever were recorded in less than 40% of patients. Echocardiography showed vegetations in 92% and 100% of the patients with B. henselae and B. quintana, respectively. Culture was positive only in one patient and the remaining were diagnosed by serology and PCR. PCR was the most useful tool allowing for diagnosis in 16 patients (100% of the studied valves). Serology, at titers recommended by guidelines, only coincided with PCR in 52.4%. Antimicrobial therapy, in different combinations, was used in all cases. Surgery was performed in 76% of the patients. No in-hospital mortality was observed. One-year mortality was 9.4%. This article remarks the importance for investigating the presence of Bartonella infection as causative agent in all BCNE since the diagnosis needs specific microbiological tools and patients could benefit of a specific treatment.

Bartonella spp. Prevalence (Serology, Culture, and PCR) in Sanitary Workers in La Rioja Spain

Bartonella spp. are increasingly implicated in association with a spectrum of zoonotic infectious diseases. One hundred sanitary workers in La Rioja, Spain completed a questionnaire and provided blood specimens for Bartonella spp. serology and Bartonella alpha-Proteobacteria growth medium (BAPGM) enrichment blood culture/PCR. Six immunofluorescence assays (IFA) were performed and aseptically obtained blood specimens were inoculated into liquid BAPGM and subcultured onto blood agar plates. Bartonella DNA was amplified using conventional and real-time PCR assays. The Bartonella spp., strain, or genotype was determined by DNA sequencing. Bartonella seroreactivity was documented in 83.1% and bloodstream infection in 21.6% of participants. Bartonella henselae, B. vinsonii subsp. berkhoffii genotypes I and III, and B. quintana were identified. IFA seroreactivity and PCR positivity were not statistically associated with self-reported symptoms. Our results suggest that exposure to and non-clinical infection with Bartonella spp. may occur more often than previously suspected in the La Rioja region.

Prevalence of Bartonella spp. by culture, PCR and serology, in veterinary personnel from Spain

Background

The genus Bartonella includes fastidious, facultative intracellular bacteria mainly transmitted by arthropods and distributed among mammalian reservoirs. Bartonella spp. implicated as etiological agents of zoonoses are increasing. Apart from the classical Bartonella henselae, B. bacilliformis or B. quintana, other species (B. elizabethae, B. rochalimae, B. vinsonii arupensis and B. v. berkhoffii, B. tamiae or B. koehlerae, among others) have also been associated with human and/or animal diseases. Laboratory techniques for diagnosis (culture, PCR assays and serology) usually show lack of sensitivity. Since 2005, a method based on a liquid enrichment Bartonella alphaproteobacteria growth medium (BAPGM) followed by PCRs for the amplification of Bartonella spp. has been developed. We aimed to assess culture, molecular and serological prevalence of Bartonella infections in companion animal veterinary personnel from Spain.

Methods

Each of 89 participants completed a questionnaire. Immunofluorescence assays (IFA) using B. vinsonii berkhoffii (genotypes I, II and III), B. henselae, B. quintana and B. koehlerae as antigens were performed. A cut-off of 1:64 was selected as a seroreactivity titer. Blood samples were inoculated into BAPGM and subcultured onto blood agar plates. Bartonella spp. was detected using conventional and quantitative real-time PCR assays and DNA sequencing.

Results

Among antigens corresponding to six Bartonella spp. or genotypes, the lowest seroreactivity was found against B. quintana (11.2%) and the highest, against B. v. berkhoffii genotype III (56%). A total of 27% of 89 individuals were not seroreactive to any test antigen. Bartonella spp. IFA seroreactivity was not associated with any clinical sign or symptom. DNA from Bartonella spp., including B. henselae (n = 2), B. v. berkhoffii genotypes I (n = 1) and III (n = 2), and B. quintana (n = 2) was detected in 7/89 veterinary personnel. PCR and DNA sequencing findings were not associated with clinical signs or symptoms. No co-infections were observed. One of the two B. henselae PCR-positive individuals was IFA seronegative to all tested antigens whereas the other one was not B. henselae seroreactive. The remaining PCR-positive individuals were seroreactive to multiple Bartonella spp. antigens.

Conclusions

High serological and molecular prevalences of exposure to, or infection with, Bartonella spp. were found in companion animal veterinary personnel from Spain. More studies using BAPGM enrichment blood culture and PCR are needed to clarify the finding of Bartonella PCR-positive individuals lacking clinical symptoms.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2483-z) contains supplementary material, which is available to authorized users.

Bartonella Species, an Emerging Cause of Blood-Culture-Negative Endocarditis

Since the reclassification of the genus Bartonella in 1993, the number of species has grown from 1 to 45 currently designated members. Likewise, the association of different Bartonella species with human disease continues to grow, as does the range of clinical presentations associated with these bacteria. Among these, blood-culture-negative endocarditis stands out as a common, often undiagnosed, clinical presentation of infection with several different Bartonella species. The limitations of laboratory tests resulting in this underdiagnosis of Bartonella endocarditis are discussed. The varied clinical picture of Bartonella infection and a review of clinical aspects of endocarditis caused by Bartonella are presented. We also summarize the current knowledge of the molecular basis of Bartonella pathogenesis, focusing on surface adhesins in the two Bartonella species that most commonly cause endocarditis, B. henselae and B. quintana. We discuss evidence that surface adhesins are important factors for autoaggregation and biofilm formation by Bartonella species. Finally, we propose that biofilm formation is a critical step in the formation of vegetative masses during Bartonella-mediated endocarditis and represents a potential reservoir for persistence by these bacteria.

First description of Bartonella koehlerae infection in a Spanish dog with infective endocarditis

BACKGROUND

Bartonella koehlerae has been recently described as a new cat- and cat fleas-associated agent of culture-negative human endocarditis. It has been also encountered in one dog from Israel and six dogs from the USA, but other clinically relevant reports involving this bacterium are lacking.

RESULTS

A 7-year-old intact male mixed dog presented with clinico-pathological signs consistent with mitral endocarditis and cutaneous hemangiosarcoma. Molecular studies revealed the presence of Bartonella koehlerae DNA in samples from blood and mitral valve tissue.

CONCLUSIONS

This is the first description of B. koehlerae in Spain, corroborating that it can also be detected in dogs. Bartonella koehlerae infection should also be considered in Spain in humans and dogs presenting with clinical disease suggestive of it, such as culture-negative endocarditis.

Bartonella as a cause of blood culture-negative endocarditis. Description of five cases

There is evidence that Bartonella is an etiologic factor in human endocarditis. The objective of this article was to describe cases of endocarditis due to Bartonella observed at a tertiary-care hospital during 1995-2006. Overall, 140 cases of infective endocarditis were seen, of which 10 were blood culture-negative endocarditis, with five being due to Bartonella. In four cases, there had been contact with cats. Only two patients had pre-existing cardiac valvular disease. Three had extracardiac disease manifestations. In three cases, polymerase chain reaction (PCR) tests on cardiac valvular tissue gave positive results. Two patients had positive serology test results for Chlamydophila and another two, positive results for Coxiella burnetii. All five patients needed surgery, and the outcome was favorable in all five. The presence of Bartonella must be considered in patients with blood culture-negative endocarditis. Although serological testing is essential for the diagnosis, cross-reactions between Bartonella and C. burnetii or Chlamydophila are frequent, and PCR tests on cardiac valvular tissue, therefore, play an important diagnostic role.

Serological evidence for the association of Bartonella henselae infection with arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden death in young adults. On the basis of histopathological findings its pathogenesis may involve both a genetic origin and an inflammatory process. Bartonella henselae may cause endomyocarditis and was detected in myocardium from a young male who succumbed to sudden cardiac death.

HYPOTHESIS

We hypothesized that chronic infection with Bartonella henselae could contribute to the pathogenesis of ARVC.

METHODS

We investigated sera from 49 patients with ARVC for IgG antibodies to Bartonella henselae. In this study, 58 Swiss blood donors tested by the same method served as controls.

RESULTS

Six patients with ARVC (12%) had positive (>1:256) IgG titres in the immunofluorescence test with Bartonella henselae. In contrast, only 1 elevated titre was found in 58 controls (p < or = 0.05). Interestingly, all patients with increased titres had no familial occurrence of ARVC.

CONCLUSIONS

Further studies in larger patient cohorts seem justified to investigate a possible causal link between chronic Bartonella henselae and ARVC, in particular its sporadic (nonfamilial) form.

[Infective endocarditis due to Bartonella henselae following a rupture of a cerebral aneurysm]

We report a case of severe aortic bicuspid valve endocarditis, revealed by global cardiac failure without fever, in a 38-year-old man who had developed cerebral mycotic aneurysms nine months earlier. PCR analysis of the excised aortic valve and serological tests (even 9 months earlier) were positive for Bartonella henselae. A combination of intravenous then oral doxycyclin at 200mg/day and intravenous gentamycin at 90mg/day was given for 6 and 2 weeks respectively. The evolution was favorable on follow-up, 12 months after completion of the therapy. Only 49 cases of B. henselae endocarditis have been reported to date, none with associated mycotic aneurysm but most often located on the bicuspid aortic valve, and usually with severe valvular damage due to late diagnosis.

Transmission of Bartonella henselae by Ixodes ricinus

The causative agent of cat-scratch disease in humans can be transmitted by this tick through saliva.

Bartonella spp. are facultative intracellular bacteria associated with several emerging diseases in humans and animals. B. henselae causes cat-scratch disease and is increasingly associated with several other syndromes, particularly ocular infections and endocarditis. Cats are the main reservoir for B. henselae and the bacteria are transmitted to cats by cat fleas. However, new potential vectors are suspected of transmitting B. henselae, in particular, Ixodes ricinus, the most abundant ixodid tick that bites humans in western Europe. We used a membrane-feeding technique to infect I. ricinus with B. henselae and demonstrate transmission of B. henselae within I. ricinus across developmental stages, migration or multiplication of B. henselae in salivary glands after a second meal, and transmission of viable and infective B. henselae from ticks to blood. These results provide evidence that I. ricinus is a competent vector for B. henselae.