Bartonella and Coxiella antibodies in 334 prospectively studied episodes of infective endocarditis in Sweden

Clinical Significance of a 16S-rDNA Analysis of Heart Valves in Patients with Infective Endocarditis: a Retrospective Study

A substantial proportion of patients with infective endocarditis (IE) are subjected to heart valve surgery. Microbiological findings on valves are important both for diagnostics and for tailored antibiotic therapy, post-operatively. The aims of this study were to describe microbiological findings on surgically removed valves and to examine the diagnostic benefits of 16S-rDNA PCR and sequencing (16S-analysis). Adult patients who were subjected to heart valve surgery for IE between 2012 and 2021 at Skåne University Hospital, Lund, where a 16S-analysis had been performed on the valve, constituted the study population. Data were gathered from medical records, and the results from blood cultures, valve cultures, and 16S-analyses of valves were compared. A diagnostic benefit was defined as providing an agent in blood culture negative endocarditis, providing a new agent in episodes with positive blood cultures, or confirming one of the findings in episodes with a discrepancy between blood and valve cultures. 279 episodes in 272 patients were included in the final analysis. Blood cultures were positive in 259 episodes (94%), valve cultures in 60 episodes (22%), and 16S-analyses in 227 episodes (81%). Concordance between the blood cultures and the 16S-analysis was found in 214 episodes (77%). The 16S-analyses provided a diagnostic benefit in 25 (9.0%) of the episodes. In blood culture negative endocarditis, the 16S-analyses had a diagnostic benefit in 15 (75%) of the episodes. A 16S-analysis should be routinely performed on surgically removed valves in blood culture negative endocarditis. In patients with positive blood cultures, 16S-analysis may also be considered, as a diagnostic benefit was provided in some patients. IMPORTANCE This work demonstrates that it can be of importance to perform both cultures and analysis using 16S-rDNA PCR and sequencing of valves excised from patients undergoing surgery for infective endocarditis. 16S-analysis may help both to establish a microbiological etiology in cases of blood culture negative endocarditis and to provide help in situations where there are discrepancies between valve and blood cultures. In addition, our results show a high degree of concordance between blood cultures and 16S-analyses, indicating that the latter has a high sensitivity and specificity for the etiological diagnosis of endocarditis in patients who were subjected to heart valve surgery.

Infectious endocarditis caused by Bartonella henselae associated with infected pets: two case reports

BACKGROUND

Blood culture-negative infective endocarditis is a potentially severe disease that can be associated with infectious agents such as Bartonella spp., Coxiella burnetti, Tropheryma whipplei, and some fungi.

CASE PRESENTATION

Reported here are two cases of blood culture-negative infective endocarditis in patients with severe aortic and mitral regurgitation in Brazil; the first case is a 47-year-old white man and the second is a 62-year-old white woman. Bartonella henselae deoxyribonucleic acid was detectable in the blood samples and cardiac valve with vegetation paraffin-fixed tissue samples. Additionally, an investigation was carried out on patients' pets, within the context of One Health, and serum samples collected from cats and dogs were reactive by indirect immunofluorescence assay.

CONCLUSIONS

Even though the frequency of bartonellosis in Brazil is unknown, physicians should be aware of the possibility of blood culture-negative infective endocarditis caused by Bartonella, particularly in patients with weight loss, kidney changes, and epidemiological history for domestic animals.

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 quintana as a cause for prosthetic valve endocarditis and post-sternotomy mediastinitis

An otherwise healthy patient, with minimal clinical, biochemical and peroperative signs of infection, was diagnosed with Bartonella quintana prosthetic valve endocarditis by 16S PCR. The patient subsequently developed a post-sternotomy mediastinitis and Bartonella quintana was the only detected pathogen. Bartonella quintana can cause severe infections in individuals not classically at risk, and may be missed in the routine diagnostic work-up of endocarditis.

Three Separate Clinical Entities of Infective Endocarditis-A Population-Based Study From Southern Finland 2013-2017

Background

Health care–associated infective endocarditis (HAIE) and intravenous drug use–related IE (IDUIE) have emerged as major groups in infective endocarditis (IE). We studied their role and clinical picture in a population-based survey.

Methods

A population-based retrospective study including all adult patients diagnosed with definite or possible IE in Southern Finland in 2013–2017. IE episodes were classified according to the mode of acquisition into 3 groups: community-acquired IE (CAIE), HAIE, and IDUIE.

Results

Total of 313 episodes arising from 291 patients were included. Incidence of IE was 6.48/100 000 person-years. CAIE accounted for 38%, HAIE 31%, and IDUIE 31% of IE episodes. Patients in the IDUIE group were younger, and they more frequently had right-sided IE (56.7% vs 5.0%; P < .001) and S. aureus as etiology (74.2% vs 17.6%; P < .001) compared with the CAIE group. In-hospital (15.1% vs 9.3%; P = .200) and cumulative 1-year case fatality rates (18.5% vs 17.5%; P = .855) were similar in CAIE and IDUIE. Patients with HAIE had more comorbidities, prosthetic valve involvement (29.9% vs 10.9%; P = .001), enterococcal etiology (20.6% vs 5.9%; P = .002), and higher in-hospital (27.8% vs 15.1%; P = .024) and cumulative 1-year case fatality rates (43.3% vs 18.5%; P < .001) than patients with CAIE. Staphylococcus aureus caused one-fifth of IE episodes in both groups.

Conclusions

Our study indicates that in areas where injection drug use is common IDUIE should be regarded as a major risk group for IE, along with HAIE, and not seen as part of CAIE. Three different risk groups, CAIE, HAIE, and IDUIE, with variable characteristics and outcome should be recognized in IE.

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.

Bartonellaspecies as a cause of infective endocarditis in the UK

Bartonellaspp. are increasingly implicated in infectious endocarditis cases in the UK. Herein, we attempted to quantify their role in this syndrome and explored the epidemiology ofBartonella-associated endocarditis in the UK. Between November 2005 and October 2010, samples from 685 endocarditis patients were submitted to the Health Protection Agency forBartonellaserology. Serological evidence of infection was obtained for 57 (8·3%) patients. PCR-based evidence of infection was obtained from 13 out of 14 patients for whom heart valve tissue was available, withBartonella quintanaimplicated in 12 cases andB. henselaein one. Six patients withB. quintanaendocarditis were recent immigrants into the UK, of whom four lived in poor socioeconomic conditions. These results indicate thatBartonellais a not uncommon cause of endocarditis in the UK and should be considered particularly in patients raised in eastern Europe and/or with a history of homelessness or alcoholism.

Bartonella spp. infection in HIV positive individuals, their pets and ectoparasites in Rio de Janeiro, Brazil: serological and molecular study

BACKGROUND

Bartonella is the agent of cat-scratch disease, but is also responsible for more severe conditions such as retinitis, meningoencephalitis, endocarditis and bacillary angiomatosis. Its seroprevalence is unknown in Brazil.

METHODS

Patients in an AIDS clinic, asymptomatic at the time of the study, were enrolled prospectively. They answered a structured questionnaire and had blood taken for serological and molecular assays. Cat breeder's pets were tested serologically and collected ectoparasites were tested by molecular biology techniques. Blood donors, paired by age and sex, were tested for Bartonella IgG antibodies.

RESULTS

125 HIV positive patients with a median age of 34 were studied; 61 were male and 75% were on HAART. Mean most recent CD4 count was 351-500 cells/mm(3). A high rate of contact with ticks, fleas and lice was observed. Bartonella IgG seroreactivity rate was 38.4% in HIV positive individuals and breeding cats was closely associated with infection (OR 3.6, CI 1.1-11.9, p<0.05). No difference was found between the sexes. Titers were 1:32 in 39 patients, 1:64 in seven, 1:128 in one and 1:256 in one. In the control group, IgG seroreactivity to Bartonella spp. was 34%, and female sex was correlated to seropositivity. Fourteen of 61 (23%) males vs 29/64 (45.3%) females were seroreactive to Bartonella (OR 2.8, CI 1.2-6.5, p<0.01). Titers were 1:32 in 29 patients, 1:64 in ten and 1:128 in four.

CONCLUSIONS

Bartonella spp. seroprevalence is high in HIV positive and in blood donors in Rio de Janeiro. This may be of public health relevance.

Clinical presentation, etiology, and outcome of infective endocarditis in the 21st century: the International Collaboration on Endocarditis-Prospective Cohort Study

BACKGROUND

We sought to provide a contemporary picture of the presentation, etiology, and outcome of infective endocarditis (IE) in a large patient cohort from multiple locations worldwide.

METHODS

Prospective cohort study of 2781 adults with definite IE who were admitted to 58 hospitals in 25 countries from June 1, 2000, through September 1, 2005.

RESULTS

The median age of the cohort was 57.9 (interquartile range, 43.2-71.8) years, and 72.1% had native valve IE. Most patients (77.0%) presented early in the disease (<30 days) with few of the classic clinical hallmarks of IE. Recent health care exposure was found in one-quarter of patients. Staphylococcus aureus was the most common pathogen (31.2%). The mitral (41.1%) and aortic (37.6%) valves were infected most commonly. The following complications were common: stroke (16.9%), embolization other than stroke (22.6%), heart failure (32.3%), and intracardiac abscess (14.4%). Surgical therapy was common (48.2%), and in-hospital mortality remained high (17.7%). Prosthetic valve involvement (odds ratio, 1.47; 95% confidence interval, 1.13-1.90), increasing age (1.30; 1.17-1.46 per 10-year interval), pulmonary edema (1.79; 1.39-2.30), S aureus infection (1.54; 1.14-2.08), coagulase-negative staphylococcal infection (1.50; 1.07-2.10), mitral valve vegetation (1.34; 1.06-1.68), and paravalvular complications (2.25; 1.64-3.09) were associated with an increased risk of in-hospital death, whereas viridans streptococcal infection (0.52; 0.33-0.81) and surgery (0.61; 0.44-0.83) were associated with a decreased risk.

CONCLUSIONS

In the early 21st century, IE is more often an acute disease, characterized by a high rate of S aureus infection. Mortality remains relatively high.

Native valve endocarditis due to Bartonella henselae in an immunocompetent man

Culture-negative endocarditis accounts for 2.5-31% of all endocarditis cases and remains a diagnostic and therapeutic challenge. Bartonella spp. has only recently been recognized as an important cause of culture-negative endocarditis. We report a case of Bartonella henselae endocarditis occurring in an immunocompetent man who owned a cat and had previously been diagnosed with valvulopathy. Diagnosis was made only after prolonged diagnostic work-up with serology and with PCR and subsequent sequencing to identify the microorganism in the excised valves. The duration of treatment in patients with bartonella endocarditis is not clearly defined, and we decided to treat our patient with a prolonged course of antibiotic. Surgical treatment is usually necessary and was also successful in our patient. To our knowledge, this is the first case of bartonella endocarditis occurring in our geographic area.

Swedish guidelines for diagnosis and treatment of infective endocarditis

Swedish guidelines for diagnosis and treatment of infective endocarditis (IE) by consensus of experts are based on clinical experience and reports from the literature. Recommendations are evidence based. For diagnosis 3 blood cultures should be drawn; chest X-ray, electrocardiogram, and echocardiography preferably transoesophageal should be carried out. Blood cultures should be kept for 5 d and precede intravenous antibiotic therapy. In patients with native valves and suspicion of staphylococcal aetiology, cloxacillin and gentamicin should be given as empirical treatment. If non-staphylococcal etiology is most probable, penicillin G and gentamicin treatment should be started. In patients with prosthetic valves treatment with vancomycin, gentamicin and rifampicin is recommended. Patients with blood culture negative IE are recommended penicillin G (changed to cefuroxime in treatment failure) and gentamicin for native valve IE and vancomycin, gentamicin and rifampicin for prosthetic valve IE, respectively. Isolates of viridans group streptococci and enterococci should be subtyped and MIC should be determined for penicillin G and aminoglycosides. Antibiotic treatment should be chosen according to sensitivity pattern given 2-6 weeks intravenously. Cardiac valve surgery should be considered early, especially in patients with left-sided IE and/or prosthetic heart valves. Absolute indications for surgery are severe heart failure, paravalvular abscess, lack of response to antibiotic therapy, unstable prosthesis and multiple embolies. Follow-up echocardiography should be performed on clinical indications.

Fever of unknown origin due to zoonoses

Fevers of unknown origin have been classified as classic, nosocomial, immune-deficient, and HIV-related. More than half of the 1407 human pathogens are zoonotic, making zoonotic infections an important subcategory in each of the classifications. This article describes both common and unusual zoonoses causing fevers of unknown origin. Simian immune virus is considered as a possible emerging infection. For special populations (the homeless, zoophiliacs, those whose occupation or leisure brings them in close contact with oceans or lakes, and veterinarians), zoonotic infection potentials are discussed.

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

INTRODUCTION

Infections by Bartonella spp. include a wide spectrum of emerging and re-emerging infectious diseases, such as culture-negative endocarditis.

METHODS

Description of 3 cases of endocarditis due to Bartonella spp. and review of those previously reported in Spain.

RESULTS

Including these 3 new cases of endocarditis due to Bartonella spp., a total of 6 cases have been reported in Spain. The median age of the patients was 51.6 years and 83.3% were men. There was history of contact with cats in 66.7%, and 50% were alcoholic. Only one patient had prior valvular disease. There were no clinical manifestations typical to any of the Bartonella species. The aortic valve was the one most commonly affected. In all cases, B. henselae was the agent implicated. The diagnosis was made by serology in 5 cases (83.3%). The outcome was favorable in all patients, although 4 of them (66.7%) required valve replacement.

CONCLUSION

Endocarditis due to Bartonella spp. is present in Spain and is likely to be underestimated. We should suspect this pathogen in patients with negative blood cultures and a history of chronic alcoholism, homeless patients, and those who have had contact with cats or who have been bitten by fleas or lice, as well as patients with endocarditis and positive serology against Chlamydia spp.

New insight into the diagnosis of fastidious bacterial endocarditis

Sterile blood cultures are noted in one third of patients with infectious endocarditis. Although in half of cases this is due to previous antibiotic therapy, in the other half, the aetiology of culture-negative endocarditis is intracellular bacteria such as Coxiella burnetii or fastidious growing bacteria. Although it was previously considered that the prevalence of such organisms was identical throughout the world, recent investigations on Bartonella endocarditis clearly showed that the aetiology of culture-negative endocarditis is likely to be strongly related to epidemiology of the agent in each country. During the past decade the use of molecular techniques such as PCR with subsequent sequencing to detect or to identify bacteria in valves from patients with infectious endocarditis have considerably improved the aetiological diagnosis. This is especially true in the case of culture-negative endocarditis following earlier antibiotic therapy. However, the fact that DNA remnants of past endocarditis can be detected some time after the acute episode, when the patient has been cured, suggests that the predictive value of these techniques along with the traditional histology and culture need to be evaluated closely.

Contribution of systematic serological testing in diagnosis of infective endocarditis

Despite progress with diagnostic criteria, the type and timing of laboratory tests used to diagnose infective endocarditis (IE) have not been standardized. This is especially true with serological testing. Patients with suspected IE were evaluated by a standard diagnostic protocol. This protocol mandated an evaluation of the patients according to the modified Duke criteria and used a battery of laboratory investigations, including three sets of blood cultures and systematic serological testing for Coxiella burnetii, Bartonella spp., Aspergillus spp., Legionella pneumophila, and rheumatoid factor. In addition, cardiac valvular materials obtained at surgery were subjected to a comprehensive diagnostic evaluation, including PCR aimed at documenting the presence of fastidious organisms. The study included 1,998 suspected cases of IE seen over a 9-year period from April 1994 to December 2004 in Marseilles, France. They were evaluated prospectively. A total of 427 (21.4%) patients were diagnosed as having definite endocarditis. Possible endocarditis was diagnosed in 261 (13%) cases. The etiologic diagnosis was established in 397 (93%) cases by blood cultures, serological tests, and examination of the materials obtained from cardiac valves, respectively, in 348 (81.5%), 34 (8%), and 15 (3.5%) definite cases of IE. Concomitant infection with streptococci and C. burnetii was seen in two cases. The results of serological and rheumatoid factor evaluation reclassified 38 (8.9%) possible cases of IE as definite cases. Systematic serological testing improved the performance of the modified Duke criteria and was instrumental in establishing the etiologic diagnosis in 8% (34/427) cases of IE.

Bacterial zoonoses and infective endocarditis, Algeria

Blood culture–negative endocarditis is common in Algeria. We describe the etiology of infective endocarditis in this country. Samples from 110 cases in 108 patients were collected in Algiers. Blood cultures were performed in Algeria. Serologic and molecular analysis of valves was performed in France. Infective endocarditis was classified as definite in 77 cases and possible in 33. Causative agents were detected by blood cultures in 48 cases. All 62 blood culture–negative endocarditis cases were tested by serologic or molecular methods or both. Of these, 34 tested negative and 28 had an etiologic agent identified. A total of 18 infective endocarditis cases were caused by zoonotic and arthropodborne bacteria, including Bartonella quintana (14 cases), Brucella melitensis (2 cases), and Coxiella burnetii (2 cases). Our data underline the high prevalence of infective endocarditis caused by Bartonella quintana in northern Africa and the role of serologic and molecular tools for the diagnosis of blood culture–negative endocarditis.