Semiquantitative species-specific detection of Bartonella henselae and Bartonella quintana by PCR-enzyme immunoassay

Application of metagenomic next-generation sequencing in the diagnosis of Bartonella neuroretinitis: a case report and literature review

BACKGROUND

Cat-scratch disease (CSD) is caused by Bartonella henselae infection. In atypical cases of CSD, pathogen determination is challenging. We report a case of Bartonella neuroretinitis with neither a clear history of scratches nor typical general symptoms. The diagnosis was made using metagenomic next-generation sequencing (mNGS), a high-throughput sequencing technology.

CASE PRESENTATION

A female patient presented to the ophthalmologist with complaint of blurred vision in her right eye. Although with history of raising a cat, she reported no clear history of scratches or typical general symptoms, except a fever of unknown origin which resolved spontaneously. The best corrected visual acuity (BCVA) of the right eye was count fingers. Fundus examination showed optic disc oedema, macular exudates and inferior exudative retinal detachment. Laboratory examination results showed increased value of serum C-reactive protein and erythrocyte sedimentation rate. Ocular involvement of toxoplasmosis, syphilis and tuberculosis were excluded. To identify the possible causative pathogen of the disease, mNGS of aqueous humour sample was performed and 521 reads of B. henselae were identified. Serological test results further showed a positive immunoglobulin G (IgG) titre of 1:64. Taking the contact history, clinical manifestations, mNGS and serological results into consideration, the diagnosis of Bartonella neuroretinitis (ocular CSD) was made. After appropriate treatment, the BCVA of the right eye improved to 20/25 in the last follow-up. Fundus examination showed a normal optic disc and macula, and the exudates had reduced.

CONCLUSION

mNGS, a fast and unbiased method, can be used to detect B. henselae (if present) in intraocular fluid samples.; however, the results should be interpreted together with the clinical symptoms and other auxiliary test results.

[Bone involvement in cat scratch disease]

INTRODUCTION

Cat scratch disease caused by Bartonella henselae with bone involvement is a rare presentation.

CASE REPORT

We report a case of disseminated bartonellosis with multifocal osteomyelitis and multiple visceral involvement in an immunocompetent adult. Diagnostic confirmation was obtained by PCR on lymphadenopathy. In addition to our observation, 31 cases of bartonellosis with bone involvement were reported in the literature. Diagnosis is based on a combination of history, serology and PCR performed on tissue. The antibiotic treatment allows recovery in all cases.

CONCLUSION

Cat scratch disease in its systemic form with bone involvement is a rare and difficult diagnosis for the clinician and an invasive approach is often required to obtain the diagnosis.

Osteomyelitis in Cat-Scratch Disease: A Never-Ending Dilemma-A Case Report and Literature Review

Background

We performed a review of published case studies of osteomyelitis associated with cat-scratch disease to consolidate existing information on clinical presentation, diagnostic tools, therapy, and outcome, as well as presenting a case of disseminated cat-scratch disease in a 12-year-old female with skull osteomyelitis and spleen involvement.

Methods

A search for articles indexed in PubMed, Embase, and Google Scholar was performed with the search terms "Bartonella," "bone," "osteomyelitis," "osteolytic," and "cat-scratch disease" limited to the immunocompetent pediatric population and articles in English.

Results

51 cases were identified. The average age was 7.8 years with equal sex distribution. Fever (84.3%), often with a prolonged course (64.7%), and osteoarticular pain (88.2%) were the most common clinical findings. Lymphadenopathy was present in 64.7% of patients. Vertebral body was mainly involved (51.9%). MRI (50%) and bone scintigraphy (48.1%) were favored to confirm osteomyelitis, while serology was the preferred microbiological diagnostic. Various antibiotics were prescribed in combined or sequential regimens, with median duration of therapy of 23 days. About 12.5% of patients did not receive any treatment. Most patients had excellent prognosis; in particular, all patients not receiving any therapy showed complete recovery and no recurrence of symptoms.

Conclusions

Bartonella henselae should be considered in differential diagnosis of localized lymphadentitis. Osteoarticular pain or limitation during cat-scratch disease in children should always be investigated for bone spreading. Owing to good prognosis, invasive procedures to obtain the bone material should be avoided. Serology is the gold standard diagnostic tool and MRI is the best radiographic technique to define bone and surrounding tissue involvement. Treatment represents a never-ending dilemma: surgical intervention or use of antibiotics is still controversial, and more studies are needed to define the best antimicrobial regimen.

Bartonella Osteomyelitis of the Acetabulum: Case Report and Review of the Literature

INTRODUCTION

Bartonella henselae commonly involves the mononuclear phagocyte system (MPS), and its most common presentation is lymphadenitis. Rarely, it can cause isolated osteomyelitis. We present a case of a 3 year old with constitutional symptoms and new onset of limp. Previously reported cases of osteomyelitis due to B. henselae are also reviewed here, keeping the index case in mind.

METHODS

We conducted a Medline search using MeSH subject headings Bartonella and osteomyelitis, limited to humans.

RESULTS

The index case is a 3-year-old female who had a subacute presentation with new-onset leg pain and fever. Subsequent imaging demonstrated osteomyelitis of the acetabulum. Multiple diagnostic attempts were unsuccessful, and the patient did not respond to empiric therapy. Despite indeterminate serology, the diagnosis of Bartonella osteomyelitis was eventually confirmed by PCR on bone biopsy of the lesion. The literature search revealed 48 publications, which were reduced to 28 when limiting articles to the English language and the pediatric population. After a report of 36 pediatric cases in 2007, there have been an additional 12 pediatric cases since 1998. Generally, these patients had a subacute presentation with relatively mild constitutional symptoms. Most commonly, bone involvement occurred as osteolytic lesions of the axial skeleton. Of the total 48 cases reported, only four reported involvement of the axial skeleton.

CONCLUSION

We present the first case, to our knowledge, of pediatric osteomyelitis of the pelvis due to B. henselae with indeterminate serologic and positive PCR results. Bartonella osteomyelitis should be included in the differential diagnosis when typical pathogens are not identified or if the patient is slow to respond to standard therapies. The sensitivity of tissue PCR for Bartonella osteomyelitis is now better than the current gold standard of serology, and new management guidelines may need to reflect this.

Bacillary angiomatosis masquerading as Kaposi's sarcoma in East Africa

BACKGROUND

Bacillary angiomatosis (BA) is a rare manifestation of infection caused by Bartonella species, which leads to vasoproliferative lesions of skin and other organs. Bacillary angiomatosis affects individuals with advanced HIV disease or other immunocompromised individuals. In sub-Saharan Africa, despite the high prevalence of HIV infection and documentation of the causative Bartonella species in humans, mammalian hosts, and arthropod vectors, BA has only rarely been described.

METHODS

Three adult patients from Uganda and Kenya with deep purple dome-shaped papules or nodules of the skin underwent punch biopsies for histopathologic diagnosis. The biopsies of all 3 patients were sent to a local pathologist as well as to a dermatopathologist at the University of California, San Francisco.

RESULTS

All 3 patients were clinically suspected to have Kaposi's sarcoma (KS), and local pathologists had interpreted the lesions as KS in 2 of the cases and nonspecific inflammation in the third. Histologic examination by dermatopathologists in the United States revealed nodular dermal proliferations of irregular capillaries lined by spindled to epithelioid endothelial cells. The surrounding stroma contained a mixed inflammatory infiltrate with lymphocytes, eosinophils, and neutrophils. Extracellular deposits of pale amphophilic granular material were noted in the surrounding stroma. A Warthin-Starry stain highlighted clumps of bacilli, confirming the diagnosis of BA.

CONCLUSIONS

These 3 cases, to our knowledge, are the first reports of BA in East Africa in the biomedical literature. Each had been originally incorrectly diagnosed as KS. We speculate BA is underdiagnosed and underreported in resource-poor regions, such as sub-Saharan Africa, that have high endemic rates of HIV infection.

Detection of Bartonella spp. DNA in clinical specimens using an internally controlled real-time PCR assay

Bartonella henselae is the causative agent of cat-scratch disease (CSD), usually presenting itself as a -self-limiting lymphadenopathy. In this chapter an internally controlled Taqman probe-based real-time PCR targeting the groEL gene of Bartonella spp. is described. This assay allows for the rapid, sensitive, and simple detection of Bartonella spp. in samples from CSD or endocarditis suspects, and it is suitable for implementation in the diagnostic microbiology laboratory.

Unknown fever and back pain caused by Bartonella henselae in a veterinarian after a needle puncture: a case report and literature review

Bartonella henselae, the etiologic agent of cat-scratch disease, rarely causes back pain and is considered to be transmitted through animal scratches and bites. Here we report a cat-scratch disease case possibly with an unusual route of transmission. The patient was a 32-year-old man, and he was working as a veterinarian in a private veterinary clinic. He sought for clinical help because of unknown fever and persistent back pain for at least a month after an accidental needle puncture. Through serological testing and molecular identifications, this clinical case was confirmed to be caused by B. henselae.

Multi-locus sequence typing of a geographically and temporally diverse sample of the highly clonal human pathogen Bartonella quintana

Bartonella quintana is a re-emerging pathogen and the causative agent of a variety of disease manifestations in humans including trench fever. Various typing methods have been developed for B. quintana, but these tend to be limited by poor resolution and, in the case of gel-based methods, a lack of portability. Multilocus sequence typing (MLST) has been used to study the molecular epidemiology of a large number of pathogens, including B. henselae, a close relative of B. quintana. We developed a MLST scheme for B. quintana based on the 7 MLST loci employed for B. henselae with two additional loci to cover underrepresented regions of the B. quintana chromosome. A total of 16 B. quintana isolates spanning over 60 years and three continents were characterized. Allelic variation was detected in five of the nine loci. Although only 8/4270 (0.002%) of the nucleotide sites examined were variable over all loci, these polymorphisms resolved the 16 isolates into seven sequence types (STs). We also demonstrate that MLST can be applied on uncultured isolates by direct PCR from cardiac valve tissue, and suggest this method presents a promising approach for epidemiological studies in this highly clonal organism. Phylogenetic and clustering analyses suggest that two of the seven STs form a distinct lineage within the population.

Guidelines for the Prevention and Treatment of Opportunistic Infections among HIV-exposed and HIV-infected children: recommendations from CDC, the National Institutes of Health, the HIV Medicine Association of the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the American Academy of Pediatrics

This report updates and combines into one document earlier versions of guidelines for preventing and treating opportunistic infections (OIs) among HIV-exposed and HIV-infected children, last published in 2002 and 2004, respectively. These guidelines are intended for use by clinicians and other health-care workers providing medical care for HIV-exposed and HIV-infected children in the United States. The guidelines discuss opportunistic pathogens that occur in the United States and one that might be acquired during international travel (i.e., malaria). Topic areas covered for each OI include a brief description of the epidemiology, clinical presentation, and diagnosis of the OI in children; prevention of exposure; prevention of disease by chemoprophylaxis and/or vaccination; discontinuation of primary prophylaxis after immune reconstitution; treatment of disease; monitoring for adverse effects during treatment; management of treatment failure; prevention of disease recurrence; and discontinuation of secondary prophylaxis after immune reconstitution. A separate document about preventing and treating of OIs among HIV-infected adults and postpubertal adolescents (Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents) was prepared by a working group of adult HIV and infectious disease specialists. The guidelines were developed by a panel of specialists in pediatric HIV infection and infectious diseases (the Pediatric Opportunistic Infections Working Group) from the U.S. government and academic institutions. For each OI, a pediatric specialist with content-matter expertise reviewed the literature for new information since the last guidelines were published; they then proposed revised recommendations at a meeting at the National Institutes of Health (NIH) in June 2007. After these presentations and discussions, the guidelines underwent further revision, with review and approval by the Working Group, and final endorsement by NIH, CDC, the HIV Medicine Association (HIVMA) of the Infectious Diseases Society of America (IDSA), the Pediatric Infectious Disease Society (PIDS), and the American Academy of Pediatrics (AAP). The recommendations are rated by a letter that indicates the strength of the recommendation and a Roman numeral that indicates the quality of the evidence supporting the recommendation so readers can ascertain how best to apply the recommendations in their practice environments. An important mode of acquisition of OIs, as well as HIV infection among children, is from their infected mother; HIV-infected women coinfected with opportunistic pathogens might be more likely than women without HIV infection to transmit these infections to their infants. In addition, HIV-infected women or HIV-infected family members coinfected with certain opportunistic pathogens might be more likely to transmit these infections horizontally to their children, resulting in increased likelihood of primary acquisition of such infections in the young child. Therefore, infections with opportunistic pathogens might affect not just HIV-infected infants but also HIV-exposed but uninfected infants who become infected by the pathogen because of transmission from HIV-infected mothers or family members with coinfections. These guidelines for treating OIs in children therefore consider treatment of infections among all children, both HIV-infected and uninfected, born to HIV-infected women. Additionally, HIV infection is increasingly seen among adolescents with perinatal infection now surviving into their teens and among youth with behaviorally acquired HIV infection. Although guidelines for postpubertal adolescents can be found in the adult OI guidelines, drug pharmacokinetics and response to treatment may differ for younger prepubertal or pubertal adolescents. Therefore, these guidelines also apply to treatment of HIV-infected youth who have not yet completed pubertal development. Major changes in the guidelines include 1) greater emphasis on the importance of antiretroviral therapy for preventing and treating OIs, especially those OIs for which no specific therapy exists; 2) information about the diagnosis and management of immune reconstitution inflammatory syndromes; 3) information about managing antiretroviral therapy in children with OIs, including potential drug--drug interactions; 4) new guidance on diagnosing of HIV infection and presumptively excluding HIV infection in infants that affect the need for initiation of prophylaxis to prevent Pneumocystis jirovecii pneumonia (PCP) in neonates; 5) updated immunization recommendations for HIV-exposed and HIV-infected children, including hepatitis A, human papillomavirus, meningococcal, and rotavirus vaccines; 6) addition of sections on aspergillosis; bartonella; human herpes virus-6, -7, and -8; malaria; and progressive multifocal leukodystrophy (PML); and 7) new recommendations on discontinuation of OI prophylaxis after immune reconstitution in children. The report includes six tables pertinent to preventing and treating OIs in children and two figures describing immunization recommendations for children aged 0--6 years and 7--18 years. Because treatment of OIs is an evolving science, and availability of new agents or clinical data on existing agents might change therapeutic options and preferences, these recommendations will be periodically updated and will be available at http://AIDSInfo.nih.gov.

Presumed Oculoglandular Syndrome fromBartonella quintana

BACKGROUND

To describe a case of clinically diagnosed oculoglandular syndrome in a 17-year-old patient that was presumed to be due to Bartonella quintana, as suggested by a positive serologic titer.

METHODS

The patient presented to the Massachusetts Eye and Ear Infirmary emergency room with signs and symptoms suggestive of oculoglandular syndrome. He had a follicular conjunctivitis with a conjunctival granuloma of the right eye and an ipsilateral large, tender submandibular lymph node. He had recently acquired a kitten and a clinical diagnosis of cat-scratch disease was made. A laboratory workup was initiated to determine the cause of this clinical presentation and empirical treatment with antibiotics was started.

RESULTS

All laboratory results were negative or normal except for the IgM titer to Bartonella quintana, which was elevated. The patient responded well to treatment and his symptoms resolved within a few weeks.

DISCUSSION

Bartonella quintana infection, a pathogen prevalent in HIV-infected, homeless, or alcoholic patients, is a possible etiologic agent of cat-scratch disease and the associated condition of oculoglandular syndrome.

Evaluation of an internally controlled real-time polymerase chain reaction assay targeting the groEL gene for the detection of Bartonella spp. DNA in patients with suspected cat-scratch disease

Bartonella (B.) henselae is the causative agent of cat-scratch disease (CSD), which usually presents as a self-limiting lymphadenopathy. This study reports the development and evaluation of an internally controlled real-time polymerase chain reaction targeting the groEL gene for detection of Bartonella spp. DNA was extracted using the MagNA Pure system. The lower detection limit was 10-100 fg DNA and the in vitro sensitivity of the assay was not affected by duplexing with an internal control PCR. The real-time PCR assay detected DNA from all five B. henselae strains tested, and from B. birtlesii, B. vinsonii subsp. vinsonii, B. vinsonii subsp. arupensis and B. doshiae. The assay generated negative results with a selection of other bacteria, including several Mycobacterium spp., Streptococcus pyogenes and Staphylococcus aureus. Results of real-time PCR in clinical samples were compared with those of a conventional 16S rDNA-based PCR assay. During the period described in the Material and methods section, real-time PCR and conventional 16S PCR were performed on 73 clinical samples. Of these samples, 29 (40%) were found to give positive results and 44 (60%) gave negative results, both by real-time PCR and by conventional PCR, with a 100% agreement between the two tests. The PCR developed in this study is a rapid, sensitive, and simple method for the detection of Bartonella spp. in CSD and is suitable for implementation in the diagnostic laboratory.

Adult systemic cat scratch disease associated with therapy for hepatitis C

Background

We describe the first case of systemic cat scratch disease in a patient receiving peginterferon α-2a and ribavirin for treatment of hepatitis C. Cases of adult systemic CSD are extremely infrequent and immunomodulatory treatment for hepatitis C has been associated with aberrant host responses to common pathogens.

Case presentation

A 52 year old man being treated for hepatitis C presented with diffuse lymphadenopathy, weight loss, fevers and splenic lesions. Symptoms were initially confused with adverse effects of his regimen, delaying recognition of his infection. Diagnostic investigation, including histopathology, microbiology and serologic parameters, confirmed that his illness was due to disseminated cat scratch disease with Bartonella henselae.

Conclusion

Disseminated CSD is exceptionally rare in adults. We describe the first case of disseminated cat scratch disease associated with peginterferon α and ribavirin to alert clinicians of the need to be aware of unusual manifestations of common infections in this population.

Diagnosis of cat scratch disease with detection of Bartonella henselae by PCR: a study of patients with lymph node enlargement

Cat scratch disease (CSD) is mostly due to Bartonella henselae after inoculation of the organism through a skin injury. Since the causative bacteria cannot be easily cultured from human lymph node samples, the diagnosis usually relies on epidemiological, clinical, histological, and serological criteria (classical criteria). A study was performed to determine the diagnostic value of PCR analysis for the detection of B. henselae for the diagnosis of CSD and its place in the diagnostic strategy alongside the classical criteria. Over a 7-year period, lymph node biopsy specimens or cytopunctures from 70 patients were systematically tested by PCR for the presence of B. henselae DNA (htrA gene) in the Bacteriology Laboratory of the Hôpitaux Universitaires de Strasbourg. Serological testing by an immunofluorescence assay for B. henselae antibodies was also performed for each patient, and clinical, epidemiological, and histological data were collected. The patients were then divided into two groups according to the number of positive diagnostic criteria for CSD: 29 patients with definite CSD (two or more classical criteria) and 15 patients with possible CSD (less than two classical criteria). The remaining 26 patients for whom another diagnosis was retained were used as a control group. Among all criteria, PCR analysis had the best specificity (100%). The PCR assay for B. henselae was positive for 22 (76%; 95% confidence interval [CI95], 56.5 to 89.7%) of the 29 definite CSD patients and 3 (20%; CI95, 4.3 to 48.1%) of the 15 possible CSD patients. We then studied combinations of diagnostic criteria, including B. henselae PCR analysis. The best diagnostic performance was observed if at least two criteria were present among serologic, epidemiologic, histological, and molecular criteria.

Cat scratch disease mimicking Richter's Syndrome in a patient with chronic lymphocytic leukemia

Richter's Syndrome is a highly refractory and usually fatal condition. It occurs as a result of transformation of chronic lymphocytic leukemia (CLL) or low grade lymphoma into highly aggressive lymphoma. Patients usually present with rapidly enlarging lymph nodes and systemic symptoms like night sweats, fever and weight loss. We are reporting a case of CLL presenting with similar symptoms. Initial suspicion of Richter's Syndrome proved wrong when lymph node biopsy did not reveal evidence of high grade lymphoma. Instead it showed findings consistent with cat scratch disease (CSD), later confirmed by serology. To our knowledge this is the first reported case of CSD in a patient with CLL.

RT-PCR-based dot blot hybridization for the detection and differentiation between porcine epidemic diarrhea virus and transmissible gastroenteritis virus in fecal samples using a non-radioactive digoxigenin cDNA probe

Multiplex reverse transcription-polymerase chain reaction (RT-PCR)-based dot blot hybridization was developed to increase the sensitivity for the detection and differentiation between porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV) in fecal samples. Fecal samples found positive by RT-PCR-based agarose gel electrophoresis were always found positive by RT-PCR-based dot blot hybridization. In addition, 5 out of 10 fecal samples which were negative for PEDV by RT-PCR-based agarose gel electrophoresis were positive for PEDV by RT-PCR-based dot blot hybridization. This RT-PCR-based dot blot hybridization increased 1000-fold in sensitivity for PEDV and 100-fold for TGEV; weakly positive bands in the agarose gel electrophoresis gave a clear positive result with dot blot hybridization.

Rapid polymerase chain reaction-based confirmation of cat scratch disease and Bartonella henselae infection

CONTEXT

Cat scratch disease (CSD) commonly occurs secondary to Bartonella henselae infection, and the diagnosis has traditionally been made by microscopic findings, the identification of organisms by cytochemistry, and clinical history. However, cytochemical analysis tends to be very difficult to interpret, and histology alone may be insufficient to establish a definitive diagnosis of CSD.

OBJECTIVE

To demonstrate the presence of B henselae in tissue suspected of involvement by CSD, using a novel polymerase chain reaction (PCR) assay.

DESIGN

Isolates of B henselae (American Tissue Culture Collection 49793) and Afipia felis (American Tissue Culture Collection 49714) were cultured on blood agar and buffered charcoal yeast extract agar, respectively. DNA was isolated from these organisms and from formalin-fixed, paraffin-embedded tissue sections with involvement by CSD (8 patients). Negative controls included water, human placental tissue, and lymph node specimens from 6 patients with reactive lymphoid hyperplasia and from 2 patients with granulomatous lymphadenitis. A primer complementary to B henselae citrate synthase gltA gene sequence was designed to perform a seminested PCR amplification. For restriction fragment length polymorphism analysis, PCR products were digested by TaqI restriction enzyme and analyzed by gel electrophoresis.

RESULTS

Seminested PCR analysis of the cultured isolates of B henselae, but not of A felis, showed specific amplification. However, nonnested PCR did not provide consistently positive results in tissue sections with CSD. Therefore, we used a seminested PCR, which revealed positivity in all of the cases with clinicopathologic diagnoses of CSD. None of the negative controls showed positivity. Restriction enzyme provided confirmation of the specific PCR amplification of the B henselae sequence.

CONCLUSIONS

Since the amplification product has a low molecular size (<200 base pairs), this assay is useful for detection of B henselae in formalin-fixed, paraffin-embedded tissues. The seminested PCR protocol described here can be used for rapid and reliable confirmation of B henselae in samples that are histologically suggestive of CSD.

[Kinetics of Bartonella spp. IgG antibodies in cat-scratch disease and in asymptomatic HIV-infected patients]

BACKGROUND AND OBJECTIVE

Our goal was to investigate the kinetics of serum IgG antibodies against Bartonella spp. in patients with cat-scratch disease and in HIV-infected indiviuals.

PATIENTS AND METHOD

Sequential determinations were made in seven patients with cat scratch disease and in seven HIV-infected individuals who were seropositive for this bacteria.

RESULTS

In five patients from each group, serum antibodies fell under the positivity threshold within two years. Two HIV coinfected patients harbored Bartonella spp. DNA in bone marrow.

CONCLUSIONS

These results suggest that the finding of a positive titer of serum IgG against Bartonella spp. is a marker of acute or recent infection.

Simple and rapid bioluminescent detection of two verotoxin genes using allele-specific PCR of E. coli O157: H7

Allele-specific PCR for E. coli O157 was conducted with primers specific to verotoxin genes, verotoxin 1 (VT1) and verotoxin 2 (VT2). VT is an important cause of haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS) worldwide. We developed a simple, rapid bioluminescent detection method for E. coli O157. The method is based on the determination of pyrophosphoric acid (PPi) released during allele-specific PCR. Thus, released PPi is converted to ATP by ATP sulphurylase and the concentration of ATP is determined using the firefly luciferase reaction. As a result, VT1, VT2 and DNA with VT1/VT2 were clearly identified by this method. This protocol, which does not require expensive equipment, can be utilized to monitor the PCR product rapidly. Additionally, this methodology can be used as a high-throughput approach for measuring PCR products.

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.

Differential detection of Bartonella species and strains in cat scratch disease diagnostics by polymerase chain reaction amplification of 16S ribosomal RNA gene

Cat scratch disease (CSD) has been difficult to diagnose in animals because of the protracted clinical course of infection and the quiescent phases when the microbial culprit lies dormant. The causative agent in CSD appears to be multiple species and strains of Bartonella. Using polymerase chain reaction (PCR) techniques for amplification of highly variable regions of the 16S ribosomal RNA (rRNA) gene sequence, a very sensitive species- and strain-specific assay for CSD-causing Bartonella species was developed. PCR primers were designed to specifically amplify the 16S rRNA gene of Bartonella species but not of other microbial pathogens. This initial PCR was multiplexed with a universal primer set, based on conserved sequence regions in the 16S rRNA gene, that provides a 162-bp fragment in all species tested. Subsequently, 3 distinct nested PCR primer sets enabled the individual amplification and specific detection of Bartonella henselae type 1, B. henselae type II, and B. clarridgeae. Thus, this 2-step PCR procedure enabled the sensitive detection and identification of these species and the B. henselae genotype by exploiting minor sequences differences. Verification of these results were demonstrated with both sequencing and ligase chain reaction techniques. The diagnostic usefulness of this CSD test has been demonstrated by the analysis of specimens from control and infected cats. The diagnosis was confirmed and the specific B. henselae strain was correctly identified in peripheral blood specimens obtained from control and strain-specific CSD-infected cats. Such an accurate and sensitive diagnostic tool for the detection and identification of CSD causative agents should be a useful for the medical, veterinary, and scientific communities.

Genomic diversity of Bartonella henselae isolates from domestic cats from Japan, the USA and France by pulsed-field gel electrophoresis

The genomic DNA diversity of 27 Bartonella henselae and three B. clarridgeiae isolates from 18 domestic cats from Japan, the USA and France was investigated by pulsed-field gel electrophoresis (PFGE) with NotI, AscI and SmaI restriction enzymes. A great diversity of genomic patterns was found for all B. henselae, but none for B. clarridgeiae isolates. The DNA size of B. henselae and B. clarridgeiae isolates were 1.7-2.9 and 1.7Mbp, respectively. All 13 Japanese cat isolates were identified as B. henselae type I. Furthermore, three of the four Japanese cats harbored genetically different B. henselae type I isolates, suggesting for the first time co-infection with various type I isolates. One French cat and one American cat were co-infected with B. henselae and B. clarridgeiae. B. henselae type I and type II were mainly grouped in two different clusters by PFGE using SmaI endonuclease in the dendrogram.

Optimization of reverse hybridization in microplates coated with rRNA targeted oligonucleotide probes

Among the modern molecular techniques for the identification of microorganisms the most straightforward way is through direct hybridization with rRNA/rDNA targeted probes. In this study, the optimization of the experimental procedures for the reverse hybridization technique in 96-well microplates is described using both synthetic model oligonucleotides (18 b) and amplified DNA (app. 4500 bp). Three different types of plates were compared (Maxi Sorp, NucleoLink, CovaLink). Plates made from nonchemically modified polystyrene which are conventionally used in immunoassays (MaxiSorp) proved to be an economic alternative for plates offering chemically modified tailor-made surfaces. Phosphorylation of the oligonucleotide probe was not necessary for successful immobilization whereas with 5'-terminal hexa-deoxyadenosine tailed capture oligonucleotides an enhanced sensitivity of the assay was observed. Variation of the stringency by adjusting different concentrations of formamide during the washing step ensures high probe specificity and therefore allows reliable identification of the microorganisms. The assay can be performed in less than 4 hours using pre-coated plates which can be stored for several weeks. After dissociation of the target DNA/capture probe duplex with an alkaline denaturing solution rehybridization is possible.

A nested array of rRNA targeted probes for the detection and identification of enterococci by reverse hybridization

Complete 23S and almost complete 16S rRNA gene sequences were determined for the type strains of the validly described Enterococcus species, Melissococcus pluton and Tetragenococcus halophilus. A comprehensive set of rRNA targeted specific oligonucleotide hybridization probes was designed according to the multiple probe concept. In silico probe design and evaluation was performed using the respective tools of the ARB program package in combination with the ARB databases comprising the currently available 16S as well as 23S rRNA primary structures. The probes were optimized with respect to their application for reverse hybridization in microplate format. The target comprising 16S and 23S rDNA was amplified and labeled by PCR (polymerase chain reaction) using general primers targeting a wide spectrum of bacteria. Alternatively, amplification of two adjacent rDNA fragments of enterococci was performed by using specific primers. In vitro evaluation of the probe set was done including all Enterococcus type strains, and a selection of other representatives of the gram-positive bacteria with a low genomic DNA G+C content. The optimized probe set was used to analyze enriched drinking water samples as well as original samples from waste water treatment plants.

Recent Advances in Diagnosis and Treatment of Cat Scratch Disease

The cause of cat scratch disease (CSD), first described in France in 1950 and in the United States in 1951, was unknown until 1983 when the bacterium in lymph nodes was detected using a Warthin-Starry silver stain. Afipia felis has been an infrequent cause of CSD since1988, when this gram-negative bacterium was first isolated from 10 patients with CSD. In 1992 Bartonella organisms were isolated from immunocompetent and immunocompromised patients. An indirect fluorescent antibody test to detect bartonella-specific serum immunoglobulins was developed in 1992. Since then multiple studies have shown that three Bartonella species may produce either CSD in humans, usually Bartonella henselae or Bartonella clarridgeiae, or bacteremia in healthy cats. Also, these two bacteria and Bartonella quintana cause bacillary angiomatosis, bacillary peliosis, or relapsing bacteremia in humans. Cats are healthy carriers of Bartonella organisms and may be bacteremic for months to years. Cat-to-cat transmission of Bartonella organisms involves the cat flea in absence of direct contact transmission. CSD is the most common cause of regional lymphadenitis in children and adolescents. Present knowledge on the etiology, clinical features, epidemiology, pathogenesis, diagnosis, and management of CSD are presented. Also, brief comments about the etiology, clinical presentation, and treatment of bacillary angiomatosis and bacillary peliosis are provided.