Diagnosis of 22 new cases of Bartonella endocarditis

Molecular detection of Bartonella quintana, B. koehlerae, B. henselae, B. clarridgeiae, Rickettsia felis, and Wolbachia pipientis in cat fleas, France

The prevalences of Bartonella, Rickettsia, and Wolbachia were investigated in 309 cat fleas from France by polymerase chain reaction (PCR) assay and sequencing with primers derived from the gltA gene for Rickettsia, the its and pap31 genes for Bartonella, and the 16S rRNA gene for Anaplasmataceae. Positive PCR results were confirmed by using the Lightcycler and specific primers for the rOmpB of Rickettsia and gltA of Bartonella. R. felis was detected in 25 fleas (8.1%), W. pipientis, an insect symbiont, in 55 (17.8%), and Bartonella in 81 (26.2%), including B. henselae (9/81; 11.1%), B. clarridgeiae (55/81; 67.9%), B. quintana (14/81; 17.3%), and B. koehlerae (3/81; 3.7%). This is the first report of the amplification of B. quintana from fleas and the first description of B. koehlerae in fleas from an area outside the United States. Cat fleas may be more important vectors of human diseases than previously reported.

Cure of bartonella endocarditis of a prosthetic aortic valve without surgery: value of serologic follow-up

Bartonella species are emerging as an important cause of blood culture-negative endocarditis, but the optimal management of this disease has not been fully defined. We describe a case of subacute Bartonella henselae endocarditis of a prosthetic aortic valve in an immunocompetent woman that was cured with long-term antibiotic therapy alone. In addition, we demonstrate that follow-up of serologic titers against B. henselae was helpful in assessing definitive cure of the infection.

Blood culture negative endocarditis: analysis of 63 cases presenting over 25 years

OBJECTIVE

To analyse cases of blood culture negative endocarditis (BCNE) seen at St Thomas' Hospital, London, between 1975 and 2000.

METHODS

Data on all episodes of endocarditis with negative blood cultures seen at St Thomas' Hospital between 1975 and 2000 were collected prospectively and analysed retrospectively.

RESULTS

Sixty three patients with BCNE were seen during the study period: 48 (76%) with native and 15 (24%) prosthetic valve infection. BCNE accounted for 12.2% of the 516 cases of endocarditis seen at St Thomas' Hospital. The diagnosis of endocarditis was clinically definite by the Duke criteria in only 21% (7 of 34) of cases of pathologically proven native valve endocarditis but in 62% (21 of 34) of cases by the St Thomas' modifications of the criteria. Comparable figures for the 11 cases of pathologically proven prosthetic valve endocarditis were 45% and 73%. Despite negative blood cultures a causative organism was identified in 31 (49%) of the 63 cases: in 15 by serology (8 Coxiella burnetii, 6 Bartonella species, and 1 Chlamydia psittaci); in 9 cases by culture of the excised valve; in 3 by microscopy of the excised valve, on which large numbers of Gram positive cocci were seen although the culture was sterile; and in the other 4 by isolation from a site other than the excised valve (2 respiratory specimens, 1 from the pacemaker tip, and 1 from an excised embolus). In addition 5 of the 6 cases of Bartonella infection were confirmed by polymerase chain reaction study of the excised valve. Two thirds of the 32 patients for whom no pathogen was identified had received antibiotics before blood was cultured. Thus truly "negative" endocarditis was very uncommon (6% of the cases).

CONCLUSION

If blood cultures are negative in definite or suspected endocarditis, serum should be analysed for Bartonella, Coxiella, and Chlamydia species antibodies, and the excised valve or (rarely) embolus should be analysed by microscopy, culture, histology, and relevant polymerase chain reaction. Other specimens may be relevant. The Duke criteria performed poorly in BCNE; St Thomas' additional minor criteria gave more definite diagnoses.

Diagnosis of Bartonella endocarditis by a real-time nested PCR assay using serum

Bartonella endocarditis is a severe disease for which blood cultures frequently remain negative. We tested three PCR assays by using specimens of serum sampled early during the disease from 43 patients diagnosed in our laboratory as having Bartonella endocarditis on the basis of serological, culture, and/or valvular molecular detection. We tested a two-step nested PCR (TSN-PCR), a one-step nested PCR (OSN-PCR) with a regular thermal cycler, and a one-step nested PCR with the LightCycler (LCN-PCR). These assays were performed with primers derived from the riboflavin synthase-encoding gene ribC, never before amplified in our laboratory. Due to contamination of negative controls, the results of the TSN-PCR were not interpretable, and this technique was no longer considered. The LCN-PCR had a specificity of 100% and a sensitivity of 58.1%, higher than those of the OSN-PCR (18.6%; P < 0.01) and prolonged blood culturing (7.1%; P < 0.01). The LCN-PCR results correlated strictly with those of other direct diagnostic tests, when available, and identified the causative species for six patients previously diagnosed on the basis of serological analysis only. The efficacy of the LCN-PCR was not influenced by antibiotics (P = 0.96) but was altered by prolonged storage of serum specimens at -20 degrees C (P = 0.04). Overall, the LCN-PCR is specific and more sensitive than traditional methods (i.e., culturing and/or PCR with EDTA-treated blood). It can easily be applied to the diagnosis of patients with suspected Bartonella endocarditis, especially when only serum is available.

Molecular diagnosis of infective endocarditis by PCR amplification and direct sequencing of DNA from valve tissue

We used broad-range eubacterial PCR amplification followed by direct sequencing to identify microbial pathogens in heart valve material from 29 patients with histologically confirmed infective endocarditis and 23 patients free of infective endocarditis. Microorganisms cultured by conventional techniques matched those identified by PCR in 21 cases. PCR alone identified the causative agent in three cases (Streptococcus bovis, Staphylococcus cohnii, and Coxiella burnetii), allowing better patient management. PCR corrected the initial bacteriological diagnosis in three cases (Streptococcus bovis, Streptococcus mutans, and Bartonella henselae). Among the 29 cases of histologically confirmed infective endocarditis, PCR findings were positive in 27 cases and were consistent with the bacterial morphology seen at Gram staining (26 cases) or with the results obtained by immunohistologic analysis with an anti-C. burnetii monoclonal antibody (one case). In two other cases of histologically confirmed infective endocarditis, PCR remained negative in a blood culture-negative case for which no bacteria were seen at histological analysis and in one case with visualization of cocci and blood cultures positive for Enterococcus faecalis. Ten clinical diagnoses of possible infective endocarditis were ruled out by histopathological analysis of the valves and subsequently by PCR. PCR was negative in 13 of the 14 patients in whom infective endocarditis was rejected on clinical grounds; the other patient was found to have Coxiella burnetii infective endocarditis on the basis of PCR and histopathological analysis and was subsequently included in the group of 29 definite cases. In total, PCR contributed to the diagnosis and management of infective endocarditis in 6 of 29 (20%) cases.

Western immunoblotting for Bartonella endocarditis

To differentiate infectious endocarditis (IE) from other Bartonella infections and to identify infecting Bartonella bacteria at the species level on a serological basis, we used Western immunoblotting to test sera from 51 patients with Bartonella IE (of which 27 had previously benefited from species identification by molecular techniques), 11 patients with chronic Bartonella quintana bacteremia, and 10 patients with cat scratch disease. Patients with IE were Western blot positive in 49 of 51 cases, and significant cross-reactivity with three heterologous Bartonella antigens was found in 45 of 49 cases. Sera from bacteremic patients did not react with more than one heterologous antigen, and sera from patients with cat scratch disease gave negative results. Sera reacted only with B. henselae in four cases of IE, including one with a positive PCR result for valve tissue. Western blot and cross-adsorption performed on serum samples from patients with IE (the identity of the causative species having been determined by PCR) were demonstrated to identify efficiently the causative species in all cases. When applied to patients diagnosed on the basis of serological tests only, this technique allowed identification of the causative species in 20 of 22 cases. The results were in accordance with epidemiological features. Six reactive bands of B. quintana (of molecular sizes from 10 to 83 kDa) demonstrated significant association with sera from patients with B. quintana endocarditis. Overall, Western blotting and cross-adsorption made it possible to identify the causative species in 49 of 51 (96%) IE cases.

Bartonella henselae and Bartonella elizabethae as potential canine pathogens

Bartonella henselae or Bartonella elizabethae DNA from EDTA-anticoagulated blood samples obtained from four dogs was amplified and sequenced. The results showed that B. elizabethae should be added to the list of Bartonella species (i.e., B. vinsonii subsp. berkhoffii, B. henselae, and B. clarridgeiae) that are currently recognized as infectious agents in dogs. Furthermore, these results may have potential zoonotic implications, particularly if dogs can serve as a previously unrecognized reservoir for B. henselae. Although the clinical relevance of these observations remains to be determined, it is possible that molecular diagnostic techniques such as PCR may help to implicate a spectrum of Bartonella spp. as a cause of or a cofactor in chronic canine and human diseases of poorly defined causation.

Laboratory diagnosis of Bartonella infections

Bartonella species are pathogens of emerging and reemerging significance, causing a wide array of clinical syndromes. In North America and Europe, they are increasingly recognized as a cause of culture negative endocarditis, neuroretinitis, and disease among homeless, HIV-infected, and other immunosuppressed individuals. In South America, bartonellosis continues to plague those in endemic regions and poses a significant threat to travelers in these areas. As the clinician is increasingly faced with these illnesses, which may be difficult to diagnose, laboratory techniques to confirm or refute the diagnosis are becoming increasingly important. Culture methods have improved over the past decade demonstrating increased sensitivity, but still require prolonged periods before isolation of the organism. Specimen handling, media selection, and growth conditions all may affect results and must be optimized in order to provide the highest likelihood of recovering the organism. Pure culture of the bacteria not only provides morphologic information, but also provides material for further diagnostic testing. Work with liquid media, which may provide a more rapid means of cultivation has shown some promise and should continue to be pursued. Improved blood culture techniques were a primary factor in the discovery of Bartonella endocarditis and continued improvements will likely demonstrate further clinical insights. Serologic testing for B henselae infections has become the cornerstone of clinical diagnosis, replacing the skin test that was poorly standardized and posed a potential risk to the patient. Immunofluorescence assays have been well characterized and validated in clinical trials, however they are not universally available. Vero cell cocultivated antigens appear to provide higher sensitivity and specificity when compared with agar-derived antigens. IFA assays are inherently difficult to perform, requiring significant expertise to provide reproducible results. On the contrary, enzyme immunoassays offer ease of use and a high level of reproducibility, however ideal antigens for use in the diagnosis of Bartonella infections have not been clearly identified. Continued work to define antigenic targets of the human response to infection and incorporation of these into a widely available EIA will provide a cost-effective tool for the clinician and epidemiologist alike. Due to the close phylogenetic relationship of B henselae and B quintana, differentiation between these species by serologic means may prove difficult. Molecular techniques including PCR offer high sensitivity and specificity, rapid availability of information, and the ability to differentiate Bartonella organisms at the highest level. Results of studies to date are promising and as methods are refined it will be important to conduct clinical studies to define the role of these assays. In disseminated Bartonella infections such as bacillary angiomatosis, peliosis, endocarditis, and urban trench fever, PCR currently offers the ability to establish the diagnosis when other tests may be unrevealing. For CSD, this technique should be used as a confirmatory technique when the diagnosis is unclear by other means. PCR analysis of blood specimens offers a minimally invasive approach to diagnosis, but clinical data are scarce and further studies are needed. As DNA microarrays move into the clinical arena, specific hybridization probes may allow improved identification and differentiation of Bartonellae at the molecular level.

The changing clinical aspects of infective endocarditis: descriptive review of 90 episodes in a French teaching hospital and risk factors for death

OBJECTIVE

We wanted to describe the epidemiological aspects of infective endocarditis (IE) in a French hospital and identify the prognostic factors.

METHODS

We reviewed the clinical, echocardiographic and microbiological features, and the outcome of 89 patients (90 episodes, median age 60 years) with IE over 18 months. Logistic regression analysis was used to identify prognostic factors for death.

RESULTS

A native valve was involved in 68 cases (75.5%); in 7 of these the patient was an intravenous drug user. A prosthetic valve was involved in 22 cases (24.5%); 5 of these were of early onset. Diagnosis was definite in 87% of cases. Median time to diagnosis was 3 days. Twenty-five patients (28%) were immunocompromised. A portal of entry, usually cutaneous, was identified in 65% of cases. Sixty-two percent of patients had an underlying heart disorder, usually degenerative. The infection involved the left heart in more than 75% of cases. One or more vegetations were detected in 75% of cases. The median size of vegetation was 15 mm. Isolated agents were mainly staphylococci (n=40 (44%), including 12 coagulase-negative isolates), and streptococci (n=23 (25%), including 7 enterococci). In 11 cases (12%), cultures remained negative. Nineteen episodes were nosocomial and Staphylococcus aureus was implicated in 11 of them. Fifty percent of patients had at least one complication: heart failure (n=42), kidney failure (n=44), embolism (n=35), septic shock (n=19). Surgery was performed in 49 cases (54%) due to heart failure (n=19), cerebral embolism (n=12), and/or severe valve lesions (n=27). Eighteen patients died, 10 of whom were infected with S. aureus. Nosocomial IE (P=0.0008), heart failure (P=0.004) and prosthetic valve (P=0.01), but not S. aureus were independently associated with death.

CONCLUSIONS

S. aureus was the main microorganism isolated in our patients. However, it was not independently predictive of fatal outcome.

Bartonella quintana Bacteremia among Homeless People

Bartonella quintana infections have recently reemerged, predominantly among the homeless populations in cities in both Europe and the United States. B. quintana can cause trench fever, endocarditis, and chronic bacteremia; the human body louse is the only known vector. Homeless people who presented to the emergency departments of University Hospital in Marseilles, France, were studied, as were those who had been admitted to other medical facilities in the city since 1 January 1997. Samples of blood and body lice were collected for culture for B. quintana and for serological testing. Bartonella bacteremia was associated with sweats, evidence of louse infestation, serological tests that were positive for B. quintana, and high titers of B. quintana antibody. Bacteremia was also associated with being homeless for <3 years. Asymptomatic, prolonged bacteremia (duration, up to 78 weeks) and intermittent bacteremia were found to occur. Data obtained regarding antibiotic regimens showed that treatment with gentamicin and doxycycline was effective in preventing relapses of bacteremia.

High rate of Bartonella henselae infection in HIV-positive outpatients in Johannesburg, South Africa

The emerging opportunistic pathogen Bartonella henselae has a wide range of clinical presentation, which includes, particularly, bacillary angiomatosis. This non-random pilot survey of outpatients attending HIV clinics in Johannesburg, South Africa, sampled 188 patients, in whom there was a 10% prevalence of Bartonella bacteraemia, as determined by nested polymerase chain reaction.

Comparison of in-house and commercial slides for detection by immunofluorescence of immunoglobulins G and M against Bartonella henselae and Bartonella quintana

We compared the sensitivities and specificities of indirect fluorescent antibody tests developed in our laboratory and commercially available from Focus Technologies (FT; formerly MRL Diagnostic) for detection of serum antibodies to Bartonella spp. Serum samples tested were from patients with culture- or PCR-confirmed Bartonella quintana or B. henselae infections causing cat scratch disease (CSD), chronic bacteremia, or endocarditis. At a cutoff titer of 64, the FT test had higher sensitivity than our in-house test in detecting anti-B. henselae immunoglobulin G (IgG) antibodies in CSD patients (91.2 versus 52.9%; P < 0.001). The specificity in serum samples from 85 control patients was, however, lower with the FT test (87%) than with the in-house test (98.8%) (P = 0.002). A cutoff titer of 128 improves the specificity for the FT test but lowers the sensitivity to 85%. For patients infected with B. henselae, our in-house test, but not the FT test, enabled endocarditis to be detected more reliably. With the in-house test, titers of IgG against B. henselae of >/=1,024 were found only in endocarditis patients and not in CSD patients. With the FT test, 19.1% of CSD patients had titers of IgG against B. henselae of >/=1,024 (P < 0.001). Our in-house technique also improved detection of anti-B. quintana antibodies in homeless patients with endocarditis. IgG titers of >/=1,024 were present in 75% of serum samples, but only in 16.7% of serum samples with the FT test (P = 0.004). Since each test has advantages over the other, the serological diagnosis of Bartonella infections would benefit if both tests were used concurrently.

Value of microimmunofluorescence for diagnosis and follow-up of Bartonella endocarditis

Bartonella endocarditis is a disease of emerging importance that causes serious complications and high rates of mortality. Due to the fastidious nature of Bartonella species and their high degrees of antibiotic susceptibility, cultures of clinical samples most often remain sterile and valvular biopsy specimens, the best specimens for PCR amplification, are seldom available. Therefore, serology appears to be the easiest diagnostic tool. In order to determine the best cutoff value for serology and its predictive values for the detection of Bartonella endocarditis, we studied 48 patients with culture- and/or PCR-confirmed Bartonella endocarditis. We also applied these serological criteria to 156 patients with blood culture-negative endocarditis. Furthermore, we compared the kinetics of the antibody responses to Bartonella spp. in order to estimate the value of serology for prediction of the occurrence of relapses. A titer of > or = 1:800 for immunoglobulin G antibodies to either Bartonella henselae or B. quintana has a positive predictive value of 0.810 for the detection of chronic Bartonella infections in the general population and a value of 0.955 for the detection of Bartonella infections among patients with endocarditis. When this cutoff was applied to 156 patients with blood culture-negative endocarditis, we were able to diagnose Bartonella infections in an additional 45 patients with definite endocarditis for whom a positive Bartonella serology was the only evidence of infection. On follow-up, the kinetics of the decrease in antibody titers were significantly delayed in two patients with relapses. In conclusion, we recommend the determination of antibodies to both B. quintana and B. henselae and the use of a cutoff value of 1:800 for the diagnosis of Bartonella endocarditis. We propose that this criterion, which may also help with the detection of late relapses, be included as a major criterion in the Duke criteria for the diagnosis of infective endocarditis.

Molecular methods for diagnosis of infective endocarditis

The culture of viable microorganisms from the blood or from cardiac tissue is currently the most important test for diagnosis of IE. This is followed by phenotypic identification methods used for taxonomic positioning of isolates. However, in those cases where the invading microorganism is difficult or impossible to culture (including instances of prior antimicrobial treatment), molecular methods provide the best means for detection. Molecular identification methods, either nucleic acid target or signal amplification alone or in combination with sequence analysis can offer a more specific and in some cases a more rapid alternative to the phenotypic methods. We propose revised Duke criteria of IE, including positive identification of an organism by molecular biology methods.

Diagnostic methods current best practices and guidelines for identification of difficult-to-culture pathogens in infective endocarditis

Culture-negative endocarditis currently represents a diagnostic challenge for physicians. Traditional methods such as histology, serology, and culture have been improved and new molecular techniques have been developed to improve the detection of difficult-to-culture agents. Serologic tests for the two most frequent etiologic agents, Coxiella burnetii and Bartonella spp, should be performed first because they can usually be identified easily in this way. The sensitivity of culture for intracellular bacteria has been improved by inoculation of samples in shell vials and by the use of novel tissue cell lines. Recently, universal and species-specific primers have been designated to amplify bacterial DNA directly from resected valves, allowing positive identification.

Genotypic characteristics of two serotypes of Bartonella henselae

The study of 16S rRNA gene sequences of all isolates of Bartonella henselae obtained in our laboratory and others from human patients or cats has revealed two genotypes according to the sequence of the 16S rRNA gene. Two isolates of these genotypes have previously been related to two different serotypes, and lack of cross-protection of the two serotypes has been demonstrated in cats. We investigated the grouping of eight strains of B. henselae on the basis of 16S ribosomal DNA, 35-kDa protein, Pap 31 protein, and internal transcribed spacer (ITS) gene sequencing; sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles; and monoclonal antibody reactivity studies. Houston-1, 90-615, and SA2 strains showed the same patterns in SDS-PAGE, but they differed from the patterns of B. henselae isolates URBHLLY8, URBHLIE9, Cat6, Fizz, and CAL-1. Nine monoclonal antibodies derived from BALB/c mice immunized with B. henselae Houston-1 strain reacted only with strains Houston-1, 90-615, and SA2, and not with any other Bartonella strains. The two serogroups corresponded with two genotypes based on differences in the sequences of the genes encoding 16S rRNA, 35-kDa protein, and Pap 31 protein. Sequences of ITS genes were highly divergent among strains, as each had a unique sequence and the subdivision was not supported by DNA-DNA relatedness study. Study of 22 additional strains of B. henselae isolated from French bacteremic cats demonstrated that they all belong to one or the other of the proposed serotype or genotype.

Diagnostic methods current best practices and guidelines for histologic evaluation in infective endocarditis

Infective endocarditis (IE) often presents diagnostic and therapeutic challenges and continues to cause high morbidity and mortality. Confirmation of the diagnosis of IE is important for the purposes of epidemiologic and clinical studies and is crucial for patient management. Despite recent advances in diagnostic techniques, about 10% of IE cases remain culture-negative. Because pathological examination of cardiac valves to demonstrate vegetations and valvular inflammation remains the gold standard for the diagnosis of IE, the role of the pathologist is often decisive, especially when bacteriologists fail to isolate a microorganism or when a microorganism that has been isolated may be a contaminant. Furthermore, the pathologist may play an important role in identification of previously unknown infectious agents.

Molecular diagnosis of infective endocarditis--a new Duke's criterion

The molecular approach of PCR amplification of specific gene targets and universal loci for bacteria (16S rRNA) and fungi (18S, 28S and 5.8S rRNA) and subsequent sequencing was used to identify the possible causal microbial agent(s) in blood culture (47 patients) and heart valve material (30 patients) from patients with suspected infective endocarditis (IE). Culture and molecular results were analysed with respect to the patients' clinical background and the Duke Criteria. The findings demonstrated that: (i) all patients who were definite or possible cases were positive by PCR, even patients whose blood culture and valve material were culture-negative; and (ii) all patients who were rejected as having IE were also negative by PCR, with the exception of 1 patient who had bacteraemia from another source and 5 patients whose blood culture material was believed to contain an environmental contaminant. Direct molecular identification of the aetiological agents responsible for IE from blood culture material may enable specific treatment to commence at an earlier stage of the disease and hence reduce the need for valve replacement. Such a molecular approach may aid in the diagnosis of IE and should therefore be included as an additional major criterion in the Duke's classification scheme.

Treatment and prevention of infective endocarditis

The paper presents the most recent recommendations for the treatment and prevention of infective endocarditis (IE). The treatment of IE is complex and requires close collaboration among specialists in infectious diseases, cardiology, cardiac surgery and microbiology. The mainstay of medical treatment is antibiotic therapy. Theoretical considerations regarding vegetations and antibiotics have practical consequences on the route and modalities of administration of antibiotics and on the techniques used to monitor treatment. The choice of antibiotics depends on the microorganism (streptococci, enterococci, staphylococci, HACEK group [Haemophilus sp., Actinobacillus sp., Cardiobacterium sp., Eikenella sp. and Kingella sp.], Coxiella, Brucella, Legionella, Bartonella, fungi) and on whether IE occurs on native or prosthetic valves. Treatment of IE with negative blood cultures is particularly difficult. Cardiac surgery is often needed during the bacteriologically active period (in ~50% of patients). The decision to intervene and the optimal timing of the intervention requires careful consideration of multiple potential risks: the haemodynamic risk, the infectious risk, the risk due to cardiac lesions, the risk due to extracardiac complications and the risk due to the location of infective endocarditis. Even though the efficacy of antibiotic prophylaxis of IE is not completely proven, it is recommended for selected patients who undergo an at-risk procedure. Lists of cardiac conditions and of medical procedures at risk are presented; specific antibiotic prophylactic regimens for dental and upper respiratory tract procedures in out-patients, procedures under general anaesthesia and urological and GI procedures are outlined.

Prosthetic valve endocarditis caused by Bartonella quintana

We describe the first case of Bartonella quintana endocarditis affecting a prosthetic valve in a person with no known risk factors for this infection. Bartonella should be considered as a cause of endocarditis in any clinical setting.

Serological and epidemiological analysis of the prevalence of Bartonella spp. antibodies in Swedish elite orienteers 1992-93

The emergence of the popular, physically demanding and highly nature-interactive sport of orienteering was marked in Sweden by an elevated rate of sudden unexpected cardiac deaths in young competitors during the years 1979-92, with a common underlying cause or causes suspected. Subsequently, sera were collected during 1992-93 from the elite segment of orienteers holding a nationally ranked position, and a survey compiling various epidemiological data was performed. In this study, a total of 1136 sera were analyzed by indirect-fluorescent antibody assay for the presence of IgG antibodies against 3 Bartonella spp.: B. henselae, B. elizabethae and B. quintana. In total, 31% (355/1136) were seropositive for at least 1 species of Bartonella, with titers ranging up to 1/512; 350/1136 (31%) had antibodies against B. elizabethae, 34/1136 (3.0%) against B. henselae and 16/1136 (1.4%) against B. quintana. Males and females showed equal rates of 31% seropositisity to Bartonella spp. (males 241/766; females 114/370). In comparison, 322 time-matched sera from healthy blood donors had antibodies to Bartonella spp. in 6.8% of cases (p < 0.001). The observed high prevalence of Bartonella spp. antibodies found in Swedish elite orienteers may be indicative of a connection with risk factors for the development of myocarditis and sudden unexpected cardiac death.

Subacute bartonella infection in Swedish orienteers succumbing to sudden unexpected cardiac death or having malignant arrhythmias

During the period 1979-92, an increasing number of sudden unexpected cardiac deaths (SUCD) occurred in young, Swedish, male elite orienteers. Myocarditis was the most common diagnosis in the 16 victims, and in 4 cases was also associated with fatty infiltration mimicking arrhythmogenic right ventricular cardiomyopathy (ARVC). Tissues from autopsies of 5 orienteers were tested for Bartonella by PCR targeting the gltA (citrate-synthase) gene. The products were then sequenced. Antibodies to B. henselae, B. quintana and B. elizabethae were measured by indirect fluorescence antibody assay. Bartonella spp. DNA was detected in the hearts of 4 deceased orienteers, and in the lung of a fifth deceased case. The sequences were close to B. quintana in 2 cases and identical to B. henselae in 3. Four of these 5 cases, as well as 2 additional cases of elite orienteers with ARVC, indicated antibodies to Bartonella. It is suggested that Bartonella-induced silent subacute myocarditis, eventually leading to electric instability, caused the increased SUCD rate among the Swedish orienteers. It is further suggested that Bartonella infection may be a major pathogenetic factor in the development of ARVC-like disease. Although the mode of transmission is unknown, both zoonotic/vector-borne and parenteral person-to-person transmission may be involved.

Molecular characterization of first human Bartonella strain isolated in Italy

The aim of this study was to characterize a Bartonella strain (BA-1) isolated from a blood culture of an Italian, human immunodeficiency virus-positive patient with bacillary angiomatosis. We analyzed the isolate using molecular biology methods such as whole-cell fatty acid analysis, PCR-restriction fragment length polymorphism analysis, type-specific 16S rRNA PCRs, sequence analysis of the 16S rRNA, pulsed-field gel electrophoresis, and arbitrarily primed PCR. The BA-1 isolate turned out to be a Bartonella quintana strain, similar but not identical to B. quintana Oklahoma, which was used as a control strain.

Autoimmune haemolytic anaemia triggered by Bartonella henselae infection: a case report

Bartonella henselae is a hitherto unidentified cause of autoimmune haemolytic anaemia. Here we report a case of Coombs-negative autoimmune haemolytic anaemia. The episode was preceded by exposure to a cat and a non-specific infectious syndrome. Concomitant serum titres of B. henselae antibodies were indicative of a recent infection. The case report suggests that B. henselae infection can trigger secondary autoimmune haemolytic anaemia.

Whipple's endocarditis: review of the literature and comparisons with Q fever, Bartonella infection, and blood culture-positive endocarditis

Whipple's disease is a systemic infection sometimes associated with cardiac manifestations. Recently, there has been an increase in the number of reported cases of Whipple's endocarditis. The purpose of our study was to describe this entity. Data from 35 well-described cases of Whipple's endocarditis were collected and compared with those of blood culture-positive endocarditis, Q fever endocarditis, and Bartonella endocarditis. Some patients with generalized Whipple's disease presented with cardiac involvement, among other symptoms. Others presented with a nonspecific, blood culture-negative endocarditis with no associated symptoms. In comparison with cases of endocarditis due to other causes, congestive heart failure, fever, and previous valvular disease were less frequently observed in the cases of Whipple's endocarditis. Without examination of the excised valves, the diagnosis of infective endocarditis could not have been confirmed in most cases. Treatment is not well established. Whipple's endocarditis is a specific entity involving minor inflammatory reactions and negative blood cultures, and its incidence is probably underestimated.

Aortic valve endocarditis in a dog due to Bartonella clarridgeiae

We report the first documented case of endocarditis associated with Bartonella clarridgeiae in any species. B. clarridgeiae was identified as a possible etiological agent of human cat scratch disease. Infective vegetative valvular aortic endocarditis was diagnosed in a 2.5-year-old male neutered boxer. Historically, the dog had been diagnosed with a systolic murmur at 16 months of age and underwent balloon valvuloplasty for severe valvular aortic stenosis. Six months later, the dog was brought to a veterinary hospital with an acute third-degree atrioventricular block and was diagnosed with infective endocarditis. The dog died of cardiopulmonary arrest prior to pacemaker implantation. Necropsy confirmed severe aortic vegetative endocarditis. Blood culture grew a fastidious, gram-negative organism 8 days after being plated. Phenotypic and genotypic characterization of the isolate, including partial sequencing of the citrate synthase (gltA) and 16S rRNA genes indicated that this organism was B. clarridgeiae. DNA extraction from the deformed aortic valve and the healthy pulmonic valve revealed the presence of B. clarridgeiae DNA only from the diseased valve. No Borrelia burgdorferi or Ehrlichia sp. DNA could be identified. Using indirect immunofluorescence tests, the dog was seropositive for B. clarridgeiae and had antibodies against Ehrlichia phagocytophila but not against Ehrlichia canis, Ehrlichia ewingii, B. burgdorferi, or Coxiella burnetii.

Probable atypical cat scratch disease presenting as isolated posterior pancreatic duodenal lymphadenitis and abdominal pain

We report a case involving a 15-year-old girl with atypical, clinically unsuspected cat scratch disease (CSD) presenting as isolated posterior pancreatic duodenal lymphadenitis, fever, and abdominal pain. The serological, abdominal ultrasonographic, and CT findings, as well as clinical and epidemiological data, indicate that B. henselae was likely an etiologic agent of CSD in our patient.

Bartonellosis (Carrión's disease) in the modern era

Bartonellosis remains a major problem in Peru, but many contemporary aspects of this disease have not been adequately described. We examined the cases of 145 symptomatic patients in Lima, Peru, in whom bartonellosis was diagnosed from 1969 through 1992, including 68 patients in the acute (hematic) phase and 77 patients in the eruptive (verruga) phase. In modern Peru, symptomatic patients who have acute-phase bartonellosis typically present with a febrile illness and systemic symptoms caused by profound anemia; most patients respond successfully to treatment with chloramphenicol. Patients who have eruptive-phase bartonellosis most often present with cutaneous verrugas but may have less specific symptoms, such as fever and arthralgias; diagnosis can be confirmed in such patients by Western immunoblotting, and most patients appear to respond to treatment with rifampin.

Chronic active myocarditis following acute Bartonella henselae infection (cat scratch disease)

An association between Bartonella infection and myocardial inflammation has not been previously reported. We document a case of a healthy young man who developed chronic active myocarditis after infection with Bartonella henselae (cat scratch disease). He progressed to severe heart failure and underwent orthotopic heart transplantation. Bartonella henselae, therefore, should be included among the list of infectious agents associated with chronic active myocarditis.

Native valve endocarditis due to Bartonella henselae in a middle-aged human immunodeficiency virus-negative woman

We report the case of a human immunodeficiency virus-negative woman who developed native valve endocarditis of the aortic valve due to Bartonell henselae infection. The diagnosis was established using serology and PCR analysis of excised aortic valve tissue.

Immune aspects of Bartonella

Bartonella species have been recognized as important human pathogens only recently. Until the early 1990s, this genus was represented by one species, Bartonella bacilliformis. The recent identification of other Bartonella species as the agents of cat-scratch disease and bacillary angiomatosis has left little doubt of their emerging importance as opportunistic human pathogens. Over the last decade, extensive research has been performed on Bartonella species, resulting in an explosion in our knowledge of the genetic diversity of this genus. Unusual aspects of disease sequelae have fueled worldwide interest in defining the natural history, pathology, and molecular biology of Bartonella species. While much information about these interests has been presented, the advancement of immunological knowledge regarding Bartonella species has been slow. This review discusses immunological data on Bartonella species, focusing on the three primary human pathogens of this genus: B. bacilliformis, B. quintana, and B. henselae.

Experimental model of human body louse infection using green fluorescent protein-expressing Bartonella quintana

A laboratory colony of human body lice was experimentally infected by feeding on rabbits made artificially bacteremic with a green fluorescent protein-expressing Bartonella quintana. B. quintana was detected in the gut and feces until death but not in the eggs. The life span of the lice was not modified. The rabbit model should provide valuable clues to the role of lice in the transmission of B. quintana.

High seroprevalence to Bartonella quintana in homeless patients with cutaneous parasitic infestations in downtown Paris

Bartonella quintana infections have recently been reported in homeless patients. We prospectively studied the prevalence of and the factors associated with a positive serology to B quintana in the homeless population of downtown Paris. The following data were recorded: ongoing cutaneous parasitic infestation, years of homelessness, living status, previous episodes of body pediculosis and scabies, alcoholism, intravenous drug use, known immunodepression (including undernutrition and known HIV infection), and contacts with animals. B quintana serology was performed in 57 patients and in 53 age- and sex-frequency-matched downtown Paris volunteer blood donors. Thirty-one patients (54%; 95% confidence interval [CI], 41%-68%) had a positive B quintana serology as compared with 2% in the control group (P <.0001); 8 of 57 patients (14%; 95% CI: 6%-26%) had a serologic profile of an evolving infection. Age and years of homelessness were independently associated with a positive B quintana serology with adjusted relative risks (RRs) of 2.9 (95% CI, 1.4-5.9) for age 40 years and older and 1.7 (95% CI, 1.1-2.7) for years of homelessness 3 or more. Our results suggest a high prevalence of past and recent infections with B quintana in the downtown Paris homeless population with cutaneous parasitic infestations.

Endocarditis due to rare and fastidious bacteria

The etiologic diagnosis of infective endocarditis is easily made in the presence of continuous bacteremia with gram-positive cocci. However, the blood culture may contain a bacterium rarely associated with endocarditis, such as Lactobacillus spp., Klebsiella spp., or nontoxigenic Corynebacterium, Salmonella, Gemella, Campylobacter, Aeromonas, Yersinia, Nocardia, Pasteurella, Listeria, or Erysipelothrix spp., that requires further investigation to establish the relationship with endocarditis, or the blood culture may be uninformative despite a supportive clinical evaluation. In the latter case, the etiologic agents are either fastidious extracellular or intracellular bacteria. Fastidious extracellular bacteria such as Abiotrophia, HACEK group bacteria, Clostridium, Brucella, Legionella, Mycobacterium, and Bartonella spp. need supplemented media, prolonged incubation time, and special culture conditions. Intracellular bacteria such as Coxiella burnetii cannot be isolated routinely. The two most prevalent etiologic agents of culture-negative endocarditis are C. burnetti and Bartonella spp. Their diagnosis is usually carried out serologically. A systemic pathologic examination of excised heart valves including periodic acid-Schiff (PAS) staining and molecular methods has allowed the identification of Whipple's bacillus endocarditis. Pathologic examination of the valve using special staining, such as Warthin-Starry, Gimenez, and PAS, and broad-spectrum PCR should be performed systematically when no etiologic diagnosis is evident through routine laboratory evaluation.

Quantitative analysis of valvular lesions during Bartonella endocarditis

Cardiac valve pathology was evaluated in 15 patients with confirmed diagnosis of Bartonella endocarditis. Ten were infected by Bartonella quintana and 5 by Bartonella henselae. Histologic features of these cases, including fibrosis, calcification, vegetation, pattern of inflammation, and vascularization, were compared with those of valves from 25 cases of non-Bartonella endocarditis as controls using a computerized quantitative image analysis. Pathologic and immunohistologic testing for localization of Bartonella species in resected valves included Warthin-Starry stain and polyclonal antibody-based immunodetection. Compared with other cases of infective endocarditis, cases of Bartonella endocarditis are more fibrotic and calcified, less vascularized, with less extensive vegetation and chronic inflammation. These pathologic changes are suggestive of a prolonged infection. Warthin-Starry stain and immunohistologic testing demonstrated the presence of the organism, respectively, in 11 and 10 of the 13 tested valves. Results of both staining methods showed microorganisms in extracellular locations and in regions unaccompanied by inflammation. Pathology and immunohistology may contribute to the etiologic diagnosis of Bartonella endocarditis when serology and molecular techniques are not available.

Bartonella henselae, B. quintana, and B. bacilliformis: historical pathogens of emerging significance

Bartonella species were virtually unrecognized as modern pathogens of humans until the last decade. However, identification of Bartonella species as the agents of cat-scratch disease, bacillary angiomatosis, urban trench fever, and possible novel presentations of Carrion's disease has left little doubt of the emerging medical importance of this genus of organisms. The three primary human pathogenic bartonellae, Bartonella bacilliformis (Carrion's disease), B. henselae (cat-scratch disease), and B. quintana (trench fever), present noteworthy comparisons in the epidemiology, natural history, pathology, and host-microbe interaction that this review will briefly explore.

Differentiation of Bartonella species by a microimmunofluorescence assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western immunoblotting

Bartonella species can be differentiated by microimmunofluorescence assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and immunoblotting with murine polyclonal antisera to Bartonella henselae, B. quintana, B. elizabethae, and B. bacilliformis. A pairwise comparison on the basis of SDS-PAGE protein profiles demonstrated similarity values for proteins of different Bartonella species ranging from 28.6 to 86.4%. Antigenic relationships revealed by immunoblotting with murine antisera were equivalent to those of proteins observed by SDS-PAGE. A dendrogram obtained on the basis of protein bands of SDS-polyacrylamide gels showed that Bartonella species could be divided into three groups. B. bacilliformis was distinct from all other Bartonella species; B. grahamii, B. taylorii, B. doshiae, and B. vinsonii formed a cluster, as did B. henselae, B. quintana, B. elizabethae, and B. clarridgeiae. These relationships were consistent with those revealed by parsimony trees derived from 16S rRNA and gltA gene sequencing. SDS-PAGE analysis showed that 120-, 104-, 85-, 71-, 54-, 47-, 40-, 33-, 30-, and 19-kDa proteins were present in all species, with the 54-kDa protein being the most dominant. Proteins with a molecular mass of less than 54 kDa allow the differentiation of species and are a possible target for future species-specific antibodies and antigens.

Isolation in endothelial cell cultures of chlamydia trachomatis LGV (Serovar L2) from a lymph node of a patient with suspected cat scratch disease

An inguinal lymph node, removed from a 21-year-old Romanian man suspected of having cat scratch disease, was sent to our laboratory for Bartonella culture. Lymph node specimens were inoculated on blood-enriched agar and in an endothelial cell culture system using the centrifugation shell vial technique. Bacteria were grown in cell monolayers and detected as positive with an anti-Bartonella henselae rabbit serum. However, such bacteria were identified as Chlamydia trachomatis biovar LGV serovar L2 by PCR sequencing techniques. Pathological examination of tissue biopsies was compatible with either lymphogranuloma venereum or cat scratch disease. The shell vial system is suitable for isolation of intracellular pathogens responsible for chronic lymphadenopathies, including C. trachomatis, Bartonella species, Francisella tularensis, and mycobacteria. However, care should be taken when identifying Chlamydia spp. and Bartonella spp. using polyclonal antibodies, since species of both genera have common antigens which are responsible for cross-reactions.

Bartonella vinsonii subsp. berkhoffii as an agent of afebrile blood culture-negative endocarditis in a human

We report a case of endocarditis in a human infected with Bartonella vinsonii subsp. berkhoffii, which causes bacteremia and endocarditis in dogs. Bacterial identification was established by PCR amplification and sequencing of an intergenic spacer region (ITS1), 16S ribosomal DNA, and a gene encoding citrate synthase (gltA). Bartonella antibodies were detected by immunofluorescence.

Bartonellosis. New and old

The number of species that comprise the family of Bartonellaceae, genus Bartonella, has recently increased from one to 11 species, five of which have been associated with different diseases and syndromes in humans. The rapidly growing number of human pathogens has led several investigators to regard bartonellosis and other associated syndromes as important emerging infectious diseases. This article presents the history and epidemiology, clinical features, diagnosis, and treatment of bartonellosis and associated diseases, including Carrión's disease, trench fever, endocarditis and bacteremia, bacillary angiomatosis, and cat-scratch disease.

Sequence variation in the ftsZ gene of Bartonella henselae isolates and clinical samples

In a search for methods for subtyping of Bartonella henselae in clinical samples, we amplified and sequenced a 701-bp region in the 3' end of the ftsZ gene in 15 B. henselae isolates derived from cats and humans in the United States and Europe. The ftsZ sequence variants that were discovered were designated variants Bh ftsZ 1, 2, and 3 and were compared with 16S rRNA genotypes I and II of the same isolates. There was no ftsZ gene variation in the strains of 16S rRNA type I, all of which were Bh ftsZ 1. The type II strains constituted two groups, with nucleotide sequence variation in the ftsZ gene resulting in amino acid substitutions at three positions, one of which was shared by the two groups. One 16S rRNA type II isolate had an ftsZ gene sequence identical to those of the type I strains. Variants Bh ftsZ 1 and 2 were detected in tissue specimens from seven Swedish patients with diagnoses such as chronic multifocal osteomyelitis, cardiomyopathy, and lymphadenopathy. Patients with similar clinical entities displayed either Bh ftsZ variant. The etiological role of B. henselae in these patients was supported by positive Bartonella antibody titers and/or amplification and sequencing of a part of the B. henselae gltA gene. B. henselae ftsZ gene sequence variation may be useful in providing knowledge about the epidemiology of various B. henselae strains in clinical samples, especially when isolation attempts have failed. This report also describes manifestations of atypical Bartonella infections in Sweden.