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B La Scola

Publications and source records attributed to B La Scola.

At least 19 recordsLinked to original sources
PubMed2005

Genomic and evolutionary aspects of Mimivirus.

We recently described a giant double stranded DNA virus called Mimivirus, isolated from amoebae, which might represent a new pneumonia-associated human pathogen. Its unique morphological and genomic characteristics allowed us to propose Mimivirus as a member of a new distinct Nucleocytoplasmic Large DNA viruses family, the Mimiviridae. Mimivirus-specific features, namely its size and its genomic complexity, ranged it between viruses and cellular organisms. This paper reviews our current knowledge on Mimivirus structure, life cycle and genome analysis and discusses its putative evolutionary origin in the tree of species of the three domains of life.

Acanthamoeba↗
PubMed2005

Multispacer typing technique for sequence-based typing of Bartonella quintana.

Bartonella quintana is a worldwide fastidious bacterium of the Alphaproteobacteria responsible for bacillary angiomatosis, trench fever, chronic lymphadenopathy, and culture-negative endocarditis. The recent genome sequencing of a B. quintana isolate allowed us to propose a genome-wide sequence-based typing method. To ensure sequence discrimination based on highly polymorphic areas, we amplified and sequenced 34 spacers in a large collection of B. quintana isolates. Six of these exhibited polymorphisms and allowed the characterization of 4 genotypes. However, the strain variants suggested by the noncoding sequences did not correlate with the results of pulsed-field gel electrophoresis (PFGE), which suggested a higher degree of variability. Modification of the PFGE profile of one isolate after nine subcultures confirmed that rearrangement frequencies are high in this species, making PFGE unreliable for epidemiological purposes. The low extent of sequence heterogeneity in the species suggests a recent emergence of this bacterium as a human pathogen. Direct typing of natural samples allowed the identification of a fifth genotype in the DNA extracted from a human body louse collected in Burundi. We have named the typing technique herein described multispacer typing.

Animals↗
PubMed2003

Bartonella quintana and Mycobacterium tuberculosis coinfection in an HIV-infected patient with lymphadenitis.

Cat scratch disease (CSD) is usually associated with Bartonella henselae infection in patients with a history of cat exposure, but Bartonella quintana may also be a cause of chronic lympadenopathy in patients with cat or flea contact. The lymph node histopathology of CSD and tuberculosis may be indistinguishable. We report herein the first description of lymph node coinfection with B. quintana and M. tuberculosis in a 32-year HIV-infected woman. Culture of lymph node biopsy material on Columbia agar with sheep blood and on human endothelial cells in shell vial allowed us to isolate not only B. quintana, but also M. tuberculosis hominis.

Adult↗
PubMed2002

Lack of correlation between Bartonella DNA detection within fleas, serological results, and results of blood culture in a Bartonella-infected stray cat population.

OBJECTIVE: To correlate the presence of different Bartonella species in the blood of a stray cat population trapped on a French military base with specific antibodies and species detected in cat fleas. METHODS: The prevalence of Bartonella bacteremia was investigated in 61 cats by plating frozen whole blood on blood agar plates. Identification of isolates and detection of Bartonella DNA from cat flea batches from ten cats was achieved by PCR amplification and sequencing. Antibody detection was performed by microimmunofluorescence. RESULTS: We obtained 38 isolates of Bartonella from blood. Sixteen were identified as B. clarridgeiae, 15 as B. henselae genotype/serotype Houston 1 (type I), and seven as B. henselae genotype/serotype Marseille (type II). B. henselae was detected in five fleas, and B. clarridgeiae in one flea. Sixty-one per cent of the cats had detectable antibodies against at least one species or serotype. Sixteen cats had antibodies against only one antigen. For each species, the distribution of bacteremia among the cats could not be correlated with either the distribution of infected fleas or the distribution of specific antibodies. CONCLUSIONS: The lack of correlation between Bartonella DNA detection within fleas, serological results, and results of blood culture is probably due to a lack of natural heterologous protection between species or serotypes. Cats suffer bacteremia with three Bartonella species and should therefore be considered the reservoirs of at least three human pathogens.

Animals↗
PubMed2001

Culture and immunological detection of Tropheryma whippelii from the duodenum of a patient with Whipple disease.

CONTEXT: Culture of Tropheryma whippelii has been established only once, in human fibroblast cell lines from a heart valve inoculum. Molecular-based diagnostic techniques, although highly sensitive, may be less specific. New diagnostic tools involving isolation of bacteria from contaminated intestinal biopsies and immunohistological detection need to be developed. OBJECTIVE: To describe a novel method for detection and culture of T whippelii strains. DESIGN, SETTING, AND SUBJECTS: Laboratory analysis of duodenal biopsy specimens from a patient with typical relapsing Whipple disease with intestinal involvement, performed Marseille, France, in March 2000. Biopsy specimens were decontaminated with antimicrobial agents and inoculated onto cell cultures. Mouse anti-T whippelii polyclonal antibodies were used to detect T whippelii in fixed specimens taken from the patient before and after relapse, compared with specimens from 10 controls. The genotype of the isolate was determined by amplification and sequencing of 2 DNA fragments (ITS and 23S rRNA). MAIN OUTCOME MEASURE: Isolation and genotyping of a new strain(s) of T whippelii from the case patient's biopsy specimens. RESULTS: A strain was grown from the case patient's intestinal specimen that has a genotype different from the first strain isolated. During 2 episodes of Whipple disease, T whippelii bacteria were detected by immunochemistry in the patient's duodenal biopsy specimens, but not in controls. CONCLUSIONS: A second strain of T whippelii has been isolated and a protocol for isolation from the intestine has been proven to be efficient. Immunodetection of T whippelii in intestinal biopsy specimens may provide a useful tool for the diagnosis and follow-up of patients with Whipple disease. Both techniques need further evaluation and confirmation.

Actinobacteria↗
PubMed2001

Survival of Coxiella burnetii within free-living amoeba Acanthamoeba castellanii.

OBJECTIVE: To determine whether Coxiella burnetti is able to survive within free-living amoeba. METHODS: When C. burnetii was co-cultivated with the free-living amoeba species Acanthamoeba castellanii. RESULTS: Viable bacteria were detected for 18 days. Microscopic studies confirmed the presence of bacteria within vacuoles, some of which appeared to be spore-like forms. CONCLUSION: These results indicate that free-living amoebae could provide an intracellular niche for the spore formation and survival of C. burnetii in the environment.

Acanthamoeba↗
PubMed2001

Vertebral infections caused by Haemophilus aphrophilus: case report and review.

OBJECTIVE: To review in detail clinical presentation, bacteriologic findings, associated conditions and treatment of Haemophilus aphrophilus vertebral osteomyelitis and to compare them to a case we report herein. METHODS: A Medline (National Library of Medicine) search of the literature was performed by using the key words H. aphrophilus, spondylodiscitis, discitis, and vertebral osteomyelitis. The references of the case reports were examined for additional cases, especially those cited in older articles that had not been entered onto the bibliographic database. RESULTS: A case report of spondylodiscitis due to H. aphrophilus in a 35-year-old patient with a history of dental abscess 7 months before admission is presented. The patient responded well to treatment with ceftriaxone and ciprofloxacin. To date, only 14 cases of H. aphrophilus vertebral osteomyelitis have been reported. They are usually reported in middle-aged patients, usually male. Most recent cases have been treated with fluoroquinolones. Duration of treatment usually ranges from 1 to 3 months. CONCLUSIONS: H. aphrophilus is an uncommon cause of vertebral osteomyelitis. Patients are regularly cured by antibiotic therapy, provided that a tissue biopsy is performed in order to isolate the causative bacterium.

Adult↗
PubMed2001

Description of Tropheryma whipplei gen. nov., sp. nov., the Whipple's disease bacillus.

A detailed characterization was performed of the Whipple's disease bacillus, strain Twist-MarseilleT, isolated from the cardiac valve of a patient with Whipple's disease bacillus endocarditis. This strain was isolated and maintained on human embryonic lung fibroblast monolayers, but could not be cultivated in the absence of living eukaryotic cells. Two morphological forms were observed, with differing staining properties; an intracellular form with intact and degenerating bacteria within vacuoles of infected cells and an extracellular form with masses of bacteria embedded in an extracellular matrix. Determination of the DNA G+C content confirmed that it belongs to the high-G+C gram-positive bacteria. Strain Twist-MarseilleT (= CNCM I-2202T) is proposed as the type strain of a new species within a new genus, Tropheryma whipplei gen. nov., sp. nov., that was provisionally created solely on the basis of 16S rRNA gene sequence data.

Actinobacteria↗
PubMed2001

Production of Bartonella genus-specific monoclonal antibodies.

Monoclonal antibodies (MAbs) which react with heat-resistant proteins with molecular masses of 32 to 33 kDa of 14 different Bartonella species were produced. These antibodies did not react with antigens of 26 diverse bacterial strains by microimmunofluorescence assay except MAb B3D4, which reacted with Chlamydia psittaci and Chlamydia trachomatis at low titers. The identification of a common Bartonella antigenic protein will make it possible to later produce a diagnostic antigen by cloning and expressing it in Escherichia coli. Moreover, these MAbs allow all Bartonella species to be identified to the genus level.

Animals↗
PubMed2001

Isolation of Legionella anisa using an amoebic coculture procedure.

Conventional diagnostic tests for legionellosis were negative for a 61-year-old immunocompromised man with pneumonia. However, coculture of a sputum sample with Acanthamoeba polyphaga amoebae led to the recovery of Legionella anisa. This procedure may be a sensitive and convenient diagnostic method, especially for non-Legionella pneumophila species infections that can be diagnosed only by culture.

Acanthamoeba↗
PubMed2001

Detection and culture of Bartonella quintana, Serratia marcescens, and Acinetobacter spp. from decontaminated human body lice.

As part of a survey for trench fever among homeless people in Marseilles, France, we attempted isolation of Bartonella quintana from body lice. A decontamination protocol of immersion in 70% ethanol with 0.2% iodine was devised and was tested with a laboratory colony of body lice. Lice which had been experimentally contaminated with either Escherichia coli, Staphylococcus epidermidis, or Acinetobacter spp. were successfully decontaminated, and this process did not prevent the culture of B. quintana from these lice. One hundred sixty-one lice obtained from homeless patients were studied by the protocol. B. quintana was isolated on axenic medium from 15 of 161 body lice and was detected in 41 of 161 lice by PCR. Acinetobacter spp. and Serratia marcescens were also isolated from body lice. The sensitivities of PCR and culture of B. quintana were 98 and 36%, respectively. These procedures may be useful for epidemiologic studies of trench fever and for the recovery of strains for characterization and comparison.

Acinetobacter↗