Comparison of the proliferation and excretion of Bartonella quintana between body and head lice following oral challenge.

Human body and head lice are highly related haematophagous ectoparasites but only the body louse has been shown to transmit Bartonella quintana, the causative agent of trench fever. The mechanisms by which body lice became a vector for B. quintana, however, are poorly understood. Following oral challenge, green fluorescent protein-expressing B. quintana proliferated over 9 days postchallenge with the number of bacteria being significantly higher in whole body vs. head lice. The numbers of B. quintana detected in faeces from infected lice, however, were approximately the same in both lice. Nevertheless, the viability of B. quintana was significantly higher in body louse faeces. Comparison of immune responses in alimentary tract tissues revealed that basal transcription levels of peptidoglycan recognition protein and defensins were lower in body lice and the transcription of defensin 1 was up-regulated by oral challenge with wild-type B. quintana in head but not in body lice. In addition, the level of cytotoxic reactive oxygen species generated by epithelial cells was significantly lower in body lice. Although speculative at this time, the reduced immune response is consistent with the higher vector competence seen in body vs. head lice in terms of B. quintana infection.

Isolation of Bartonella henselae, Bartonella koehlerae subsp. koehlerae, Bartonella koehlerae subsp. bothieri and a new subspecies of B. koehlerae from free-ranging lions (Panthera leo) from South Africa, cheetahs (Acinonyx jubatus) from Namibia and captive cheetahs from California.

Bartonellae are blood- and vector-borne Gram-negative bacteria, recognized as emerging pathogens. Whole-blood samples were collected from 58 free-ranging lions (Panthera leo) in South Africa and 17 cheetahs (Acinonyx jubatus) from Namibia. Blood samples were also collected from 11 cheetahs (more than once for some of them) at the San Diego Wildlife Safari Park. Bacteria were isolated from the blood of three (5%) lions, one (6%) Namibian cheetah and eight (73%) cheetahs from California. The lion Bartonella isolates were identified as B. henselae (two isolates) and B. koehlerae subsp. koehlerae. The Namibian cheetah strain was close but distinct from isolates from North American wild felids and clustered between B. henselae and B. koehlerae. It should be considered as a new subspecies of B. koehlerae. All the Californian semi-captive cheetah isolates were different from B. henselae or B. koehlerae subsp. koehlerae and from the Namibian cheetah isolate. They were also distinct from the strains isolated from Californian mountain lions (Felis concolor) and clustered with strains of B. koehlerae subsp. bothieri isolated from free-ranging bobcats (Lynx rufus) in California. Therefore, it is likely that these captive cheetahs became infected by an indigenous strain for which bobcats are the natural reservoir.

Differential gene expression in laboratory strains of human head and body lice when challenged with Bartonella quintana, a pathogenic bacterium.

Human head and body lice are obligatory hematophagous ectoparasites that belong to a single species, Pediculus humanus. Only body lice, however, are vectors of the infectious Gram-negative bacterium Bartonella quintana. Because of their near identical genomes, yet differential vector competence, head and body lice provide a unique model system to study the gain or loss of vector competence. Using our in vitro louse-rearing system, we infected head and body lice with blood containing B. quintana in order to detect both differences in the proliferation of B. quintana and transcriptional differences of immune-related genes in the lice. B. quintana proliferated rapidly in body lice at 6 days post-infection, but plateaued in head lice at 4 days post-infection. RNAseq and quantitative real-time PCR validation analyses determined gene expression differences. Eight immunoresponse genes were observed to be significantly different with many associated with the Toll pathway: Fibrinogen-like protein, Spaetzle, Defensin 1, Serpin, Scavenger receptor A and Apolipoporhrin 2. Our findings support the hypothesis that body lice, unlike head lice, fight infection from B. quintana only at the later stages of its proliferation.

Conformational differences between alpha-cyclodextrin in aqueous solution and in crystalline form. A molecular dynamics study.

The computer simulation technique of molecular dynamics is a powerful tool to delineate the conformational differences between a molecule in different environments. As an illustration, the difference between an alpha-cyclodextrin molecule in aqueous solution and in crystalline form is determined. Two molecular dynamics simulations are compared. In one simulation, one alpha-cyclodextrin form in a "truncated octahedron box" containing 611 water molecules is simulated over 90 picoseconds to mimic the solution structure. In the other simulation, the crystalline form is modelled by a molecular dynamics simulation of four unit cells in space group P2(1)2(1)2(1) containing 16 alpha-cyclodextrin molecules and 96 water molecules over a period of 15 picoseconds. The solution structure of alpha-cyclodextrin deviates by about 0.1 nm from that in the crystal and shows twice as much mobility of the atoms. The experimentally observed twist of glucose unit 5 out of alignment with the other five glucose units in the alpha-cyclodextrin torus that is present in the crystal simulation, disappears in the simulation in solution, but the glucosidic torsion angles around the ring remain asymmetric. The hydrogen-bonding patterns in crystal and in solution are rather different. This means that in a crystal structure, the molecule and its (hydration) hydrogen-bonding scheme represent only one static minimum energy picture, whereas the molecular dynamics simulations yield a description of all the many hydrogen-bonding configurations that can occur in solution.

Use of retinal biopsy to diagnose Bartonella (formerly Rochalimaea) henselae retinitis in an HIV-infected patient.

A patient with the acquired immunodeficiency syndrome developed bilateral retinitis due to a Bartonella (formerly Rochalimaea) henselae infection. A retinal biopsy was performed when severe and progressive retinal infection failed to respond to empirical treatment for cytomegalovirus and Toxoplasma gondii. The biopsy specimen was stained with routine histopathological stains and the Steiner silver stain. Ribosomal DNA was extracted from formalinfixed, paraffin-embedded retinal tissue and amplified with the polymerase chain reaction assay, using Bartonella-specific primers. The amplified DNA fragment was cloned and sequenced. Staining with hematoxylin-eosin revealed tufts of proliferating vascular endothelium with numerous fusiformappearing cells, consistent with a diagnosis of bacillary angiomatosis. A Steiner silver stain revealed numerous small bacilli in the biopsy specimen. Amplification of DNA extracted from the tissue produced a fragment of 16S ribosomal DNA of the expected size; sequencing of the DNA fragment revealed that the infection was caused by B henselae. The retinal infection was treated with minocycline, doxycycline, and ciprofloxacin with improvement in visual acuity in the ensuing 12 weeks. To our knowledge, this is the first human immunodeficiency virus-infected patient with retinitis due to B henselae who was diagnosed by the identification of silver-staining bacilli and amplification and sequencing of B henselae with a polymerase chain reaction assay using a biopsy specimen of retinal tissue. Retinal biopsy is indicated, despite its potential for serious complications, in patients with acquired immunodeficiency syndrome who have a progressive, sight-threatening retinitis that is undiagnosed and unresponsive to therapy.

Bacillary angiomatosis of the cervix and vulva in a patient with AIDS.

BACKGROUND: Bacillary angiomatosis is a clinicopathologic entity that most often is identified in the skin of patients with AIDS. This report presents an example of bacillary angiomatosis of the female genital tract. CASE: Bacillary angiomatosis presented as red-purple nodules of the vulva and cervix in a 32-year-old woman with AIDS. Histologic examination revealed the lobular epithelioid vascular proliferation and hazy clumps of bacteria that characterize bacillary angiomatosis. The diagnosis was confirmed on Warthin-Starry-stained issue and by blood cultures, which were positive for Bartonella (Rochalimaea) henselae. CONCLUSION: Accurate diagnosis of this infection is important because 1) bacillary angiomatosis is commonly mistaken for Kaposi sarcoma, 2) it is effectively treated with inexpensive antibiotics, and 3) undiagnosed and/or untreated bacillary angiomatosis may lead to overwhelming disseminated infection and death.

Bartonella-associated infections.

Bartonella-associated infections occur in immunocompetent and immunocompromised patients. The spectrum of diseases caused by Bartonella species has expanded and now includes cat-scratch disease, bacillary angiomatosis, bacillary peliosis, bacteremia, endocarditis, and trench fever. Most Bartonella-associated infections that occur in North America and Europe are caused by B. henselae or B. quintana. The domestic cat serves as the major reservoir for B. henselae; the reservoir for the modern day B. quintana infection remains unknown. Methods used to diagnose Bartonella-associated infections include histopathologic analysis of biopsy specimens, culture of tissue samples, blood culture, and serology. Available data on treatment of Bartonella-associated infections remain relatively sparse but would suggest that erythromycin or doxycycline provide the best responses.

Ocular bartonellosis.

PURPOSE: To review recent advances in the basic and clinical biology of Bartonella-related eye disease. METHOD: A review of the pertinent medical literature was performed. RESULTS: A number of novel Bartonella species have been identified over the past decade. Of these, Bartonella henselae, the etiologic agent in cat scratch disease, is most often associated with ocular complications, which may include Parinaud oculoglandular syndrome, neuroretinitis, and focal retinochoroiditis. Although cat and flea exposure appear to be the main risk factors for contracting cat scratch disease, the diagnosis of ocular bartonellosis relies primarily on the recognition of suggestive clinical signs in conjunction with positive serologic testing. B. henselae-associated ocular complications are usually self-limited but may be treated with doxycycline or erythromycin, with or without rifampin, when the infections are severe or sight-threatening. CONCLUSIONS: B. henselae infection is common and should be considered in patients with Parinaud oculoglandular syndrome, neuroretinitis, or focal retinochoroiditis, particularly when there is a history of cat or flea exposure.

Detection of Bartonella henselae by polymerase chain reaction in brain tissue of an immunocompromised patient with multiple enhancing lesions. Case report and review of the literature.

The authors report the first DNA-based diagnosis of Bartonella henselae cultured from a brain lesion in a patient with acquired immune deficiency syndrome. This human immunodeficiency virus-infected patient presented with altered mental status, fever, and diabetes insipidus. Magnetic resonance imaging revealed multifocal parenchymal and leptomeningeal involvement, which was confirmed on studies of tissue biopsy samples. Using the polymerase chain reaction and gene sequencing techniques, the authors definitively demonstrated the presence of B. henselae in the brain tissue biopsy specimen.

On the occurrence of three-center hydrogen bonds in cyclodextrins in crystalline form and in aqueous solution: comparison of neutron diffraction and molecular dynamics results.

Three-center (bifurcated) hydrogen bonds may play a role by serving as an intermediate state between different dynamically changing hydrogen bonding patterns. Hydrogen bonding configurations can be studied experimentally by neutron diffraction and theoretically by computer simulation techniques. Here, both methods are used to analyse the occurrence of three-center hydrogen bonds in crystals of cyclodextrins. Almost all experimentally observed three-center hydrogen bonds in the crystal are reproduced in the molecular dynamics (MD) simulations, even as far as the detailed asymmetric geometry is concerned. On the basis of this result a MD simulation of cyclodextrin in aqueous solution is searched for the occurrence of three-center hydrogen bonds. Significant differences are found. In solution more different three-center hydrogen bonds per alpha-cyclodextrin molecule are observed than in the crystal but the population (existence as percent of the simulation period) of each three-center hydrogen bond is lower in solution than in crystal. These may indeed serve as intermediate states in the process of changing one hydrogen bonding pattern into another.

Experimental and natural infection with Bartonella henselae in domestic cats.

Domestic cats were experimentally infected with culture propagated Bartonella henselae by intradermal (i.d.) and intravenous (i.v.) routes. Cats were more efficiently infected by the i.d. (8/8 cats) than by the i.v. (2/16) route. Bacteremia was detected 1-3 weeks following inoculation and lasted for most cats for 1-8 months. However, one naturally infected cat was observed for 24 months and was found to be cyclically bacteremic, with bacterial levels varying one hundred fold or more from one period to another. No clinical or hematologic abnormalities were observed in any of the infected cats, even at the peak of bacteremia. Two cats that had become abacteremic were resistant to reinfection when inoculated with B. henselae a second time. Horizontal transmission through intimate contact between bacteremic and susceptible cats did not occur, and antibody positive bacteremic queens did not transmit the infection to their kittens in utero, peri-partum or post-partum. Only four of the 18 kittens acquired detectable levels of maternal antibody following nursing, which disappeared by 6 weeks of age. These studies indicate that B. henselae exists in an almost perfect host-parasite relationship with its feline host, but that most cats can ultimately rid themselves of the infection. The susceptibility of cats to intradermal infection and the lack of direct cat-cat transmission are compatible with possible arthropod vectors.

Bartonella-associated infections in HIV-infected patients.

AIDS: Two species of the gram-negative bacilli Bartonella, B. henselae and B. quintana, cause disease in HIV-infected patients. If untreated, infection can be fatal. Manifestations include bacillary angiomatosis (BA), bacillary peliosis hepatis (BP), bacteremia, or a combination of these. BA and BP present as lesions, but bacteremia may be subacute and persist for months without diagnosis. Additionally, patients may acquire cat scratch disease (CSD), but this is more common in immunocompetent patients. BA lesions are usually vascular, friable, and bleed profusely when traumatized. They may be confused with Kaposi's sarcoma (KS), pyogenic granuloma, lymphoma and various subcutaneous tumors and infections. Lesions may affect almost any organ, and appear as angiomatous papules, dry scaling lesions, subcutaneous nodules, cellulitic plaques or deep, highly vascularized, soft tissue masses. Patients may have osseus BA lesions (frequently affecting the long bones); hepatic and/or splenic lesions; bacteremia; or endocarditis. To diagnose infection, lesions should be biopsied and examined. Hematoxylin and eosin staining reveal histopathologic changes; darkly staining organisms are evident after Warthin-Starry silver staining; and electron microscopy allows visualization of the bacillus. An indirect immunofluorescence antibody test (IFA) detects bartonella-specific IgG antibodies. Treatment with erythromycin for at least three months is recommended, or with doxycycline if erythromycin is not well-tolerated. Severely ill patients should receive IV doxycycline with either gentamicin or rifampin for at least four months. To prevent infection, HIV-infected people should avoid traumatic cat contact and exposure to the body louse.^ieng

Bacillary angiomatosis.

The manifestations of bacillary angiomatosis include diverse cutaneous lesions, visceral parenchymal bacillary peliosis of the spleen and liver, and involvement of single or multiple organ systems. The organisms causing BA are R. henselae and R. quintana, and these organisms have now been cultured from the spleen and cutaneous lesions of BA as well as the blood of patients with visceral and cutaneous BA. The antibiotic regimen of choice for HIV-infected patients is erythromycin 500 mg 4 x a day for 2-4 months, but relapse may necessitate lifelong suppressive therapy. We are maintaining a registry of patients with bacillary angiomatosis and request that we be contacted (415-206-8680, UCSF) if you diagnose a case, preferably before therapy is instituted.

Granulomatous hepatitis and necrotizing splenitis due to Bartonella henselae in a patient with cancer: case report and review of hepatosplenic manifestations of bartonella infection.

Bacillary angiomatosis and the related disorders of bacillary peliosis hepatis and bacillary splenitis are manifestations of infection with Bartonella henselae and Bartonella quintana in immunocompromised persons. B. henselae infection, but not B. quintana infection, is linked to contact with cats and is presumed to cause visceral cat-scratch disease. We reports a case of visceral infection by B. henselae in an adult patient with cancer who was receiving chemotherapy and had had no contact with a cat or dog. The patient--whose illness was eventually diagnosed on the basis of findings of histologic, polymerase chain reaction, and serological studies--was treated with doxycycline and rifampin, and the infection resolved. In addition, 41 cases of documented or suspected bartonella infection of the liver, spleen, or both in immunocompetent or immunocompromised hosts are reviewed.

Intra-abdominal mass associated with gastrointestinal hemorrhage: a new manifestation of bacillary angiomatosis.

Bacillary angiomatosis is a recently described vascular proliferative lesion that occurs most commonly in individuals infected with human immunodeficiency virus. Cutaneous lesions are the most frequently described manifestations of bacillary angiomatosis. However, as culture techniques and disease recognition have improved, additional manifestations have been identified in human immunodeficiency virus-infected individuals, including bacillary peliosis hepatis and isolated bacteremia. Two species of the genus Bartonella (formerly Rochalimaea), Bartonella henselae or Bartonella quintana, have been cultured from the cutaneous lesions of bacillary angiomatosis. A new manifestation of Bartonella infection is reported: an intra-abdominal mass presenting with massive gastrointestinal hemorrhage in a patient with human immunodeficiency virus infection. B. quintana was cultured from a percutaneous needle-biopsy specimen obtained from the highly vascularized intra-abdominal mass. The bacillary angiomatosis lesion resolved after 3 months of tetracycline treatment. Recognition of Bartonella infection is extremely important because it is readily treatable with antibiotic therapy.

A molecular dynamics simulation of crystalline alpha-cyclodextrin hexahydrate.

The structure of crystalline alpha-cyclodextrin (alpha-CD) hexahydrate, form I (C36H60O30.6H2O, space group P2(1)2(1)2(1)) is experimentally so well determined by X-ray and by neutron diffraction analyses that the positions of all the hydrogen atoms are available. This provides an opportunity for testing an empirical force field that is currently used in simulations of protein and nucleic acid structures by performing molecular dynamics studies employing the GROMOS program package on a system of 4 unit cells containing 16 alpha-CD molecules and 96 water molecules. A detailed comparison of the simulated and experimentally determined crystal structures shows that the experimental positions of the alpha-CD atoms are reproduced within 0.025 nm, well within the overall experimental accuracy of 0.036 nm; that the water molecules are on average within 0.072 nm from their experimental sites, with two thirds reproduced within experimental accuracy by the calculations; that high correlation is produced between the occurrence of simulated and experimentally observed hydrogen bonds. The good agreement between simulated and experimental results suggests that the tested force field is reliable.

Molecular dynamics simulation of crystalline beta-cyclodextrin dodecahydrate at 293 K and 120 K.

Molecular dynamics (MD) simulations for crystalline beta-cyclodextrin dodecahydrate (beta-CD) at two different temperatures, 293 K and 120 K, have been performed using the GROMOS program package. The calculated structural properties are compared to those obtained from neutron diffraction studies of this system at the quoted temperatures. The simulation was carried out over a period of 20 ps on four unit cells containing 8 beta-CD molecules and 96 water molecules, whereby all atoms were allowed to move. At room temperature, the experimental positions of the (non-hydrogen) glucose atoms are reproduced within 0.034 nm, a value which is smaller than the experimental (0.041 nm) or simulated (0.049 nm) overall root mean square (rms) positional fluctuation. The corresponding numbers for the low temperature study are 0.046 nm, 0.019 nm and 0.022 nm. At both temperatures the experimentally observed degree of anisotropy of the atomic motions is also found in the simulations. The comparison of a variety of structural properties leads to the conclusion that the molecular model and force field used are able to simulate the cyclodextrin system very well. Experimentally observed differences in properties as a function of number of glucose units in the CD molecule (alpha-CD, 6 versus beta-CD, 7) and as a function of temperature are qualitatively reproduced by the simulations.

The failure of routine assessment to detect histories of assault experienced by psychiatric patients.

To test the hypothesis that patients' histories of having been physically or sexually assaulted are often not elicited in routine clinical assessments, the authors reviewed the charts of 100 inpatients for any mention of such experiences. The data were compared with results of earlier research interviews in which the same 100 patients were questioned directly about assault experiences. Comparison of the two sets of data showed that only 9 percent of the assault histories obtained during research interviews were mentioned on the patients' charts. Because of the clinical significance of most major assaults, the authors recommend that clinicians routinely inquire about assault history.

Overexpression and surface localization of the Chlamydia trachomatis major outer membrane protein in Escherichia coli.

The Chlamydia trachomatis major outer membrane protein (MOMP) is the quantitatively predominant surface protein which has important functional, structural and antigenic properties. We have cloned and overexpressed the MOMP in Escherichia coli. The MOMP is surface exposed in C. trachomatis and capable of eliciting protective antibodies in infected hosts, and therefore has potential as a candidate vaccine to prevent infection with this significant human pathogen. The recombinant MOMP clone, L2rMOMP, contained the entire MOMP gene including the encoded leader sequence. Large quantities of chlamydial MOMP were expressed, some of which was processed and translocated to the E. coli surface. Surface localization of the MOMP was demonstrated by the binding of anti-MOMP monoclonal antibodies to the surface of the induced clone, and was visualized by fluorescence and electron microscopy. The induction of MOMP expression had a rapidly lethal effect on the L2rMOMP E. coli clone. Although no genetic system exists for Chlamydia, development of a stable, inducible E. coli clone which overexpresses the chlamydial MOMP permits a study of the biological properties of the MOMP, including the contribution of the MOMP variable segments to the topographical interactions which determine the antigenic structure responsible for human immune response.

Surveillance for epidemic cholera in the Americas: an assessment.

In January 1991, epidemic cholera appeared in Peru and quickly spread to many other Latin American countries. Because reporting of cholera cases was often delayed in some areas, the scope of the epidemic was unclear. An assessment of the conduct of surveillance for cholera in several countries identified some recurrent problems involving surveillance case definitions, laboratory surveillance, surveillance methods, national coordination, and data management. A key conclusion is that a simple, well-communicated cholera surveillance system in place during an epidemic will facilitate prevention and treatment efforts. We recommend the following measures: a) simplify case definitions for cholera; b) focus on laboratory surveillance of patients with diarrhea primarily in the initial stage of the epidemic; c) use predominantly the "suspect" case definition when the number of "confirmed" cases rises; d) transmit weekly the numbers of cases, hospitalized patients, and deaths to regional and central levels; e) analyze data frequently and distribute a weekly or biweekly summary; and f) report the number of cholera cases promptly to the World Health Organization.