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D Raoult

Publications and source records attributed to D Raoult.

At least 343 records · Page 19Linked to original sources
PubMed1995

Phylogenetic analysis of the genus Rickettsia by 16S rDNA sequencing.

Rickettsiae are Gram-negative bacteria which multiply only inside host cells and need arthropods either as reservoirs or as vectors. Using the polymerase chain reaction and an automated laser fluorescent DNA sequencer, we amplified and sequenced the 16S rRNA (rDNA) of all available bacteria of the genus Rickettsia. R. tsutsugamushi remained close to the other bacteria of the genus Rickettsia using this technique, contrary to previous conclusions based on the study of the Sta-58 protein antigen. We found that R. canada was not included in the typhus group, as is currently recognized, but was grouped with the rickettsiae of the spotted fever group (SFG). All the SFG rickettsiae tested were grouped in the same cluster (R. conorii, Indian tick typhus rickettsia, Astrakhan fever rickettsia, Israeli tick typhus rickettsia, HA-91, R. sibirica, R. parkeri, "R. africae", "R. slovaca", R. rickettsii, Thai tick typhus rickettsia, R. japonica, R. massiliae, R. rhipicephali, R. montana, two recent isolates GS and Bar 29, R. australis, R. akari, R. bellii and R. helvetica). The recently described ELB bacterium, the agent of the Californian murine typhus, and AB bacterium, a bacterium associated with male killing in the ladybird beetle, were found in this cluster. The sequences of R. conorii Moroccan strain/Indian tick typhus rickettsia, R. massiliae/GS and R. sibirica/HA-91 were identical. All the rickettsiae had a unique ancestor with bacteria also isolated in arthropods (Ehrlichia, Cowdria, Anaplasma, Wolbachia pipientis), eventually pathogenic for mammals and implicated in parthenogenesis and cytoplasmic incompatibility. We conclude that a unique bacterium started a stable association with arthropod ancestors and generated the observed diversity of the currently isolated members of the Rickettsiales.

Base Sequence↗
PubMed1995

Lyme disease presenting as isolated acute urinary retention caused by transverse myelitis: an electrophysiological and urodynamical study.

Several neurological manifestations of Lyme disease, both central and peripheral, have been described. Reported here is a case of acute transverse myelitis related to a Lyme neuroborreliosis that presented with isolated acute urinary retention and no lower-extremity impairment. This case, documented by urodynamic and electrophysiological investigations, partially resolved after 6 weeks of intravenous ceftriaxone, affording the removal of the indwelling catheter. Alpha blocker therapy was needed for 3 months, until the complete normalisation of urodynamic and electrophysiological records. This case study indicates that whenever urinary retention is encountered associated with acute transverse myelitis or alone, the patient should be investigated for Lyme disease.

Ceftriaxone↗
PubMed1995

Flexor tenosynovitis in the hand. An unusual aetiology.

We report an unusual case of tenosynovitis in the hand. A female farm worker aged 66 developed swelling of the middle and little fingers. Extensive synovectomy of the flexor tendon sheaths was performed, and the synovitis was found to be due to Listeria monocytogenes, which is unusual in this area. Treatment with amoxycillin and gentamicin for 10 days was replaced by trimethoprim-sulfamethoxazole for 3 weeks. There was no recurrence of infection 3 months after surgery, and flexion and extension were complete at that time.

Aged↗
PubMed1995

Q fever.

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Animals↗
PubMed1995

Prevalence of antibodies to Coxiella burnetti, Rickettsia conorii, and Rickettsia typhi in seven African countries.

The prevalences of antibodies reactive with Coxiella burnetti, Rickettsia conorii, and Rickettsia typhi were determined by indirect fluorescent antibody testing of sera from seven African countries. The seroprevalences of antibodies reactive with C. burnetti and R. conorii in countries from North Africa were similar to those reported from southern Europe. In countries of sub-Saharan Africa, the seroprevalence of antibodies reactive with C. burnetti varied greatly; the generally higher figures for West Africa, where stock breeding is prominent, suggested that domestic animals might be the main reservoirs of infection. The prevalence of antibodies to the recently described species Rickettsia africae was higher than that reported for spotted fever-group rickettsiae from elsewhere in the world and paralleled the distribution of Amblyomma species. Western blot results suggested that the antibodies detected were more likely to be reactive with R. africae than with R. conorii, the main vector of which (Rhipicephalus species) rarely feeds on humans. The seroprevalences of antibodies reactive with R. typhi were higher in coastal regions, where Rattus norvegicus--the natural host of the vector Xenopsylla--is more prevalent, than in inland areas.

Africa↗
PubMed1995

Q fever endocarditis.

Q fever is a widespread disease caused by the rickettsia Coxiella burnetii, an obligate intracellular bacteria which man usually acquires through the inhalation of infected dust from subclinically infected animals. Q fever may be acute or chronic. The chronic form mostly presents as endocarditis, which is difficult to diagnose and may ultimately be fatal. Immunocompromised conditions and underlying heart disease are the most important risk factors to consider in cases of Q fever endocarditis. The ultimate diagnosis is based on specific diagnostic tests which include serology, demonstration of C. burnetii in valvular material, isolation of C. burnetii from blood and tissue samples by cell-culture techniques as well as amplification and detection of the bacterial DNA by polymerase chain reaction. Treatment of chronic Q fever endocarditis is complex and requires long-term antibiotic therapy, sometimes associated with heart valve replacement. At the present time neither an optimal antibiotic combination nor the duration of treatment is known and patients with Q fever endocarditis require prolonged follow-up because of the possibility of later relapses.

Coxiella burnetii↗
PubMed1995

Lack of bactericidal effect of antibiotics except aminoglycosides on Bartonella (Rochalimaea) henselae.

Bartonella (Rochalimaea) henselae is a cause of peliosis hepatis and bacillary angiomatosis, and one of the putative agents of cat scratch disease. Specific therapy for B. henselae infections is not available. Treatment failures and relapses are frequent, especially following brief antibiotic courses, and this contrasts with the in-vitro susceptibility of B. henselae to most antibiotics. We decided to test the antibiotic susceptibility of B. henselae associated with murine macrophage-like cells (P388 D1) and a human endothelial cell line. We carried out a bactericidal assay in this model and in axenic broth. In both models, only aminoglycosides were bactericidal. These results suggest that aminoglycosides may be effective in the treatment of B. henselae infections.

Aminoglycosides↗
PubMed1995

Prevalence of rickettsia-like organisms and spotted fever group rickettsiae in ticks (Acari: Ixodidae) from Zimbabwe.

The prevalence of rickettsia-like organisms in ticks from Zimbabwe was determined using the hemolymph test. Amblyomma hebraeum had the highest prevalence of rickettsia-like organisms. Other species with rickettsia-like organisms included Amblyomma sparsum, Amblyomma variegatum, Hyalomma marginatum rufipes, Ripicephalus simus, Haemaphysalis leachi, Amblyomma rhinocerotis, and Hyalomma truncatum. Ticks with no demonstrable rickettsia-like organisms infection were Boophilus decoloratus, Haemaphysalis spinulosa, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, and Rhipicephalus sanguineus. Polymerase chain reaction followed by restriction fragment-length polymorphism analysis on samples of hemolymph-positive ticks showed the agent of African tick-bite fever to be present in A. hebraeum, Rickettsia conorii to be present in Rhipicephalus simus and Haemaphysalis leachi, and a spotted fever group rickettsia similar to that in Hyalomma marginatum marginatum ticks from Morocco and Portugal to be present in Hyalomma marginatum rufipes.

Animals↗
PubMed1995

Osteoarticular infection due to Coxiella burnetii in children.

We report three cases of chronic osteoarticular infections associated with Q fever in children. In two of them, serologic diagnosis was confirmed by direct immunofluorescence of Coxiella burnetii in the synovial and bone biopsy specimen. We suspect that bone infections due to Coxiella burnetii could be underdiagnosed because this etiology is not frequently seen.

Abscess↗
PubMed1995

Immunoblot cross-reactions among Rickettsia, Proteus spp. and Legionella spp. in patients with Mediterranean spotted fever.

Sera from patients suffering from Mediterranean spotted fever (i.e. an infection due to Rickettsia conorii) were studied by immunoblot to investigate cross-reactivity. A prevalence of IgM antibodies to Proteus OX 19, Proteus OX 2, to the Rickettsia typhus group, to Legionella pneumophila serovars 4 and 5, to L. bozemanii Wiga and to L. micdadei Tatlock was found. Western blot confirmed that the antibodies were directed against the lipopolysaccharide as demonstrated by proteinase K digestion of the antigens. Cross-adsorptions showed that there is a common cross-reacting epitope among L. bozemanii Wiga, R. typhi and Proteus OX 19 but cross-reacting antibodies to L. micdadei and OX 2 were distinct and independent. This IgM cross-reaction could lead to a misdiagnosis.

Antibodies, Bacterial↗
PubMed1995

MICs of 28 antibiotic compounds for 14 Bartonella (formerly Rochalimaea) isolates.

We assessed in vitro the antibiotic susceptibilities of 14 Bartonella isolates of the species B. quintana, B. vinsonii, B. henselae, and B. elizabethae. Columbia agar base supplemented with 5% horse blood was used as the antibiotic assay medium. Bacterial growth could be evaluated within 5 days after incubation of the plates at 37 degrees C in a 5% carbon dioxide atmosphere. The MICs at which 90% of isolates are inhibited (MIC90s) were 0.06 microgram/ml for penicillin G and amoxicillin and 0.25 microgram/ml for ticarcillin and cefotaxime. The MIC90s of oxacillin and cephalothin were 4 and 16 micrograms/ml, respectively. The MIC90s ranged from 1 to 4 micrograms/ml for aminoglycosides. Erythromycin, doxycycline, and rifampin displayed MIC90s of 0.12, 0.12, and 0.25 microgram/ml, respectively. MIC90s were 1 and 5 micrograms/ml for trimethoprim-and sulfamethoxazole, respectively, 64 micrograms/ml for fosfomycin, and 16 micrograms/ml for colistin and vancomycin. The study confirms the high levels of in vitro susceptibility of Bartonella agents to antibiotics.

Anti-Bacterial Agents↗
PubMed1995

Treatment of Pseudomonas aeruginosa-infected orthopedic prostheses with ceftazidime-ciprofloxacin antibiotic combination.

Indwelling device infections are associated with considerable morbidity and extremely high cost. Pseudomonas aeruginosa is the most frequent gram-negative etiologic agent associated with infections of indwelling catheters and foreign body implants. It is generally agreed that eradication of infection in the presence of a foreign body requires removal of the foreign body. Using a combination of ceftazidime and ciprofloxacin, we cured nine of nine patients with P. aeruginosa-infected osteosynthetic material and four of five patients with hip and knee prostheses without removing the foreign material. Follow-up was for a mean of 21 months (range, 6 to 60 months). Some patients experienced minor side effects (arthralgia in one patient and rash in another patient). We conclude that this combination is effective and safe and should be useful in the treatment of P. aeruginosa-infected orthopedic implants.

Adult↗
PubMed1995

Genotype characterization of the bacterium expressing the male-killing trait in the ladybird beetle Adalia bipunctata with specific rickettsial molecular tools.

The male-killing ladybird beetle (LB) bacterium (AB bacterium) was analyzed with specific rickettsial molecular biology tools in the LB Adalia bipunctata strains. Eight phenotype-positive LB strains showing mortality of male embryos were amplified with rickettsial genus-specific primers from the gene for citrate synthase (CS) and the gene for a 17-kDa protein and spotted fever group-specific primers from the gene for the 120-kDa outer membrane protein (ompB). The specificity of amplification was confirmed by Southern hybridization and the absence of the above-listed gene products in three phenotype-negative LB strains. Restriction polymorphism patterns of three examined amplicons from the CS gene, 17-kDa-protein gene, and ompB gene were identical among the eight phenotype-positive LB strains and were unique among all known rickettsiae of the spotted fever and typhus groups. Amplified fragments of the CS genes of the AB bacterium, Rickettsia prowazekii Breinl, Rickettsia typhi Wilmington, Rickettsia canada 2678, and Rickettsia conorii 7 (Malish) were sequenced. The greatest differences among the above-listed rickettsial and AB bacterium CS gene sequences were between bp 1078 and 1110. Numerical analysis based on CS gene fragment sequences shows the close relationships of the AB bacterium to the genus Rickettsia. Expanding of knowledge about rickettsial arthropod vectors and participation of rickettsiae in the cytoplasmic maternal inheritance of arthropods is discussed.

Amino Acid Sequence↗
PubMed1995

Rickettsia conorii entry into Vero cells.

The entry of rickettsiae into eukaryotic cells is mediated by an induced phagocytosis, but rickettsiae have never been observed in a closed phagocytic vacuole. In this study, Rickettsia conorii entry into Vero cells was observed by transmission electron microscopy during a period of 3 to 20 min after bacterium-cell contact. The entry occurred within 3 min after bacterium-cell contact, and R. conorii was observed in the process of engulfment, within a phagocytic vacuole, or free in the cytosol. Escape from the phagosome is a very rapid step since phagosome lysis was only occasionally observed. By 12 min, 90% of bacteria were internalized and half were free in the cytosol. This report confirms that rickettsiae penetrate nonphagocytic cells by induced phagocytosis and is the first demonstration of rickettsiae within a complete phagocytic vacuole.

Animals↗
PubMed1995

Genomic and proteinic characterization of strain S, a rickettsia isolated from Rhipicephalus sanguineus ticks in Armenia.

Strain S, a spotted fever group (SFG) rickettsia isolated from Rhipicephalus sanguineus ticks collected in Armenia, was identified. Microimmunofluorescence, sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis and Western immunoblotting, PCR and then restriction fragment length polymorphism analysis, pulsed-field gel electrophoresis, and 16S rRNA gene sequencing were used to compare strain S with reference isolates. Strain S was found to possess proteinic, antigenic, and genomic patterns which were unique among SFG rickettsiae. Strain S is characterized by its high degree of pathogenicity for experimental animals, but its role as a potential human pathogen should be determined. The role of R. sanguineus ticks in the epidemiology of SFG rickettsiae is discussed.

Animals↗
PubMed1995

Genomic study of Rickettsia akari by pulsed-field gel electrophoresis.

Pulsed-field gel electrophoresis of SmaI-, EagI-, and BssHII-digested DNA was used to perform restriction fragment length polymorphism analysis of Rickettsia akari strains isolated from humans, rodents, and mites in the United States and Ukraine. Although some differences in biological and serological characteristics were present between strains, the genomic studies demonstrated a high degree of intraspecies homogeneity of R. akari isolates. Our results confirm the value of pulsed-field gel electrophoresis-restriction fragment length polymorphism analysis for the identification of species of rickettsiae.

Animals↗
PubMed1995

Coxiella burnetii blood cultures from acute and chronic Q-fever patients.

Q fever, a worldwide zoonosis caused by Coxiella burnetii, may present as either an acute or a chronic disease. We correlated the results of 844 C. burnetii blood cultures with serological, clinical, and therapeutic data. C. burnetii was isolated from 17% of untreated patients with acute Q fever and from 53% of untreated patients with chronic Q fever. C. burnetii was not isolated from patients who were receiving antibiotics active against C. burnetii. For seven culture-positive patients with acute Q fever, serology was negative when C. burnetii was isolated. One patient with acute Q fever had a positive blood culture 25 days after the discontinuation of specific antibiotic therapy, and another had a positive blood culture after the resolution of symptoms. In one case of chronic Q fever, a positive blood culture resulted from noncompliance with treatment. The culture method described in this report is suitable for all laboratories with cell culture facilities. Our findings suggest that blood samples must be collected prior to the initiation of an antibiotic regimen if C. burnetii is to be successfully isolated.

Acute Disease↗