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D Raoult

Publications and source records attributed to D Raoult.

At least 415 records · Page 23Linked to original sources
PubMed1993

[Tick-borne diseases].

Due to their worldwide distribution, from hottest to coldest climates, and due to their behaviour, ticks are capable of transmitting numerous human and animal bacterial viral or parasitous diseases. Depending on the disease, they play the role of biological vector or intermediate host. In France, six tick borne diseases are of epidemiologic importance. Q fever (not often tick-borne), Mediterranean Spotted Fever, Lyme disease, Turalemia (human and animal), Babesiosis and Tick-borne Viral Encephalitis.

Animals↗
PubMed1993

Eikenella corrodens, a rare cause of pancreatic abscess: two case reports and review.

Eikenella corrodens, a slowly growing gram-negative bacillus that is a normal inhabitant of dental plaque, has been recognized as an infrequent cause of invasive disease. To date, only one case of pancreatic abscess due to E. corrodens in association with other bacteria from the oropharynx has been described. We report herein two cases of pancreatic abscess due to E. corrodens. In one case E. corrodens and Escherichia coli were found in the abscess specimens; in the other case no other pathogen was associated with E. corrodens. In addition, we review descriptions from the literature of abdominal infections caused by E. corrodens.

Abscess↗
PubMed1993

Antimicrobial susceptibility of Rochalimaea quintana, Rochalimaea vinsonii, and the newly recognized Rochalimaea henselae.

The susceptibility of an isolate of Rochalimaea quintana, Rochalimaea vinsonii and the newly recognized Rochalimaea henselae to antimicrobial agents was determined by dilution in Mueller-Hinton agar supplemented with 5% sheep blood. Two inocula of 10(2) and 10(4) cfu were used and tests were read after incubation at 5 and 7 days at 37 degrees C in an atmosphere enriched to 5% carbon dioxide. Each isolate was susceptible to amoxycillin, third-generation cephalosporins, tetracyclines, macrolides and rifampicin, with complete inhibition of bacterial growth at concentrations lower than 0.125 mg/L. Co-trimoxazole and aminoglycosides were also active. Conversely, MICs for oxacillin, cephalothin, clindamycin, chloramphenicol and the fluoroquinolones were around the maximum concentrations achievable in serum. Vanocomycin showed moderate activity with MICs of < or = 4 mg/L. These results are consistent with clinical experience in antibiotic treatment of R. henselae infections since failures were reported with first-generation cephalosporins and the isoxazolyl penicillins. However, the frequent relapses that are observed with other beta-lactams, tetracyclines or macrolides do not accord with the in-vitro susceptibility of Rochalimaea spp. Poor bactericidal activity as well as the intracellular growth of the bacteria within infected hosts, may explain such discrepancies.

Anti-Bacterial Agents↗
PubMed1993

Q fever and HIV infection.

OBJECTIVE: To study the frequency of Q fever in HIV-infected individuals. DESIGN: A seroprevalence study. SETTING: French National Reference Centre for Rickettsial Agents, Marseille, France. PATIENTS AND METHODS: Five out of the 68 hospitalized cases of Q fever diagnosed in 1987-1989 were also HIV-infected and are described here. Sera from a blood-donor bank (n = 925) and from HIV-positive individuals selected at random, irrespective of clinical or immunological status (n = 500) were tested for Q fever. RESULTS: Comparisons of the two groups showed a statistically significant difference (2.4 versus 0.8%; Fisher's exact test) at the diagnostic dilution 1:200 and at the dilution considered positive for seroprevalence study (1:1000). CONCLUSIONS: Using the estimated incidence of HIV infection in Marseille, the number of Q fever cases in 1987-1989 was 13 times higher and the clinical expression more frequently symptomatic in the HIV-positive population than in the general one. The prevalence:seroprevalence ratio for Q fever was 1.37% in the HIV-positive group and 0.36% in the blood-donor group. Sera positive for Q fever were confirmed by Western blot analysis in order to minimize cross-reaction. Transmission of Q fever appears to be more frequent in HIV-positive individuals than in the general population; this is not surprising, since Coxiella burnetii lives in the phagolysosome, like other micro-organisms described in immunocompromised hosts. Q fever should be added to the spectrum of diseases that occur more frequently during HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1993

Confirmation that Rickettsia helvetica sp. nov. is a distinct species of the spotted fever group of rickettsiae.

We propose the name Rickettsia helvetica sp. nov. for a rickettsial serotype of unknown pathogenicity isolated in 1979 in Switzerland from Ixodes ricinus ticks and designated the Swiss agent. The growth characteristics and the results of microimmunofluorescence serologic typing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting (immunoblotting) with specific mice sera, and a polymerase chain reaction followed by restriction fragment length polymorphism analysis confirmed previously reported preliminary findings which suggested that this rickettsia, to which a name was given provisionally, does represent a new member of the spotted fever group of rickettsiae. The type strain is C3 (Reference Center for Rickettsioses, Marseille, France).

Animals↗
PubMed1993

Rickettsia massiliae sp. nov., a new spotted fever group Rickettsia.

We propose the name Rickettsia massiliae sp. nov. (type strain, Mtu1 in the Collection of the World Health Organization Collaborative Center for Rickettsial Reference, Marseille, France) for a spotted fever group rickettsia determined to be distinct from previously recognized species by the serotyping method (L. Beati, J.-P. Finidori, B. Gilot, and D. Raoult, J. Clin. Microbiol. 30:1922-1930, 1992). This rickettsia has biological characteristics similar to those of the other spotted fever group rickettsiae. In addition, a sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein analysis, a polymerase chain reaction followed by a restriction fragment length polymorphism analysis of DNA fragments, and pulsed-field electrophoresis of the genome of R. massiliae revealed unique migration patterns distinct from those of all previously recognized spotted fever group rickettsiae. These additional characteristics (Beati et al., J. Clin. Microbiol. 30:1922-1930, 1992), together with the data usually considered sufficient for description of rickettsiae, are crucial to the proposal of this new species and should be helpful in species identification.

Animals↗
PubMed1993

In vitro susceptibilities of spotted fever group rickettsiae and Coxiella burnetti to clarithromycin.

The in vitro bacteriostatic activity of clarithromycin, a new macrolide derivative, against Rickettsia rickettsii, Rickettsia conorii, and "Rickettsia israeli" was determined by the plaque assay and the dye uptake assay. Both bacteriostatic and bactericidal activities of clarithromycin against the Nine Mile, Q212, Priscilla, and ME9 strains of Coxiella burnetti were evaluated by using three cell culture systems. Clarithromycin showed improved antibacterial activity compared with that of erythromycin. A bacteriostatic activity was obtained at concentrations below the reported maximum concentration of clarithromycin in human serum (about 4 micrograms/ml) for all tested rickettsiae. MICs ranged from 1 to 2 micrograms/ml for the three Rickettsia species and from 1 to 4 micrograms/ml for the C. burnetti strains. No bactericidal activity against C. burnetti was obtained when clarithromycin was used at 4 micrograms/ml.

Animals↗
PubMed1993

In vitro activities of ceftriaxone and fusidic acid against 13 isolates of Coxiella burnetii, determined using the shell vial assay.

The susceptibilities of 13 isolates of Coxiella burnetii to fusidic acid and ceftriaxone were determined by use of the recently described shell vial assay (D. Raoult, H. Torres, and M. Drancourt, Antimicrob. Agents Chemother, 35:2070-2077, 1991). At a concentration of 4 micrograms/ml, ceftriaxone was bacteriostatic for four isolates and slowed the multiplication of the other nine. Fusidic acid at a concentration of 2 micrograms/ml was bacteriostatic for six isolates and slowed the multiplication of three others. These results show that these compounds could be effective in the phagolysosome of C. burnetii-infected cells.

Ceftriaxone↗
PubMed1993

Oral rifampin plus ofloxacin for treatment of Staphylococcus-infected orthopedic implants.

We examined the effectiveness and safety of the combination of rifampin plus ofloxacin given orally for treating prosthetic orthopedic implants infected with staphylococci. The prospective cohort study was conducted in a referral public hospital with ambulatory care services between 1985 and 1991. Consecutive patients from whom Staphylococcus organisms susceptible to the study drugs were isolated from their orthopedic implants and who had no contraindication to the treatment were eligible for the study. All patients were treated orally with rifampin, 900 mg/day, plus ofloxacin, 600 mg/day. Patients with hip prosthesis infection were treated for 6 months, with removal of any unstable prostheses after 5 months of treatment; patients with knee prosthesis infection were treated for 9 months, with removal of the prosthesis after 6 months of treatment; and patients with infected bone plates were treated for 6 months, with removal of the plate after 3 months of treatment, if necessary. Monthly clinical evaluations were conducted until the completion of the treatment and follow-up or telephone interviews were conducted at 6, 12, 24, 36, 48, and 60 months thereafter. Treatment failures were documented by clinical evaluation, sampling of the infected site for culture and antibiotic activity measurement, and fistulography, if possible. Cure was defined as the absence of clinical, biological, and radiological evidence of infection 6 months after the completion of treatment, treatment failure was defined as the absence of cure, and relapse was defined as the reappearance of infection caused by the same Staphylococcus isolate that caused the original infection, regardless of the timing of this secondary infection. Among 51 patients included in the study and evaluable for safety, 4 patients had side effects and were not evaluable for treatment effectiveness; the overall success rate was 74% among 47 patients, with a success rate of 81% for the hip prosthesis group, 69% for the knee prosthesis group, and 69% for the osteosynthesis device group. Eight treatment failures were relaxed to the isolation of a resistant bacterium. The combination of rifampin administered orally plus ofloxacin is a suitable alternative to the conventional long-term intravenous therapy for treatment of orthopedic implants infected with staphylococci.

Administration, Oral↗
PubMed1993

Antibiotic susceptibilities of Afipia felis in axenic medium and in cells.

Afipia felis, one of the putative agents of cat scratch disease (CSD), is a facultative intracellular bacterium. Although CSD is considered not to be susceptible to antibiotic therapy, sporadic case reports indicated that aminoglycosides may be effective. We determined the in vitro antibiotic susceptibilities of three A. felis strains in axenic medium and in a cell model. In axenic medium, A. felis was susceptible to imipenem, aminoglycosides, and rifampin when using either the broth dilution technique or the agar technique. When grown in HeLa cells, A. felis was susceptible to amikacin and tobramycin but was resistant to the other compounds tested. Despite its intracellular location, A. felis can apparently be reached by aminoglycosides. Thus, the in vitro data presented here are in accord with the clinical data obtained in patients suffering CSD.

Anti-Bacterial Agents↗
PubMed1993

Genotypic identification and phylogenetic analysis of the spotted fever group rickettsiae by pulsed-field gel electrophoresis.

Using pulsed-field gel electrophoresis, we studied the chromosomes of spotted fever group rickettsiae. We digested the DNA of 16 species currently known to belong to this group with SmaI, EagI, and BssHII. The genome size of 13 rickettsiae was between 1,200 and 1,300 kb. "Rickettsia massiliae" and "R. helvetica" genome sizes were 1,370 and 1,397 kb, respectively, and that of R. bellii was 1,660 kb. It was possible to obtain distinctive patterns for each species, but in R. conorii, 10 isolates exhibited the same profiles, showing that pulsed-field gel electrophoresis is a good interspecies identification tool. We achieved a phylogenetic analysis of these bacteria by using the Dice coefficient and UPGMA and Package Philip programming. We established a dendrogram of the genetic relationships between the different species showing the existence of a cluster in the spotted fever group rickettsiae including R. conorii, R. rickettsii, R. parkeri, R. sibirica, "R. africae," "R. slovaca," Thai tick typhus rickettsia, and Israeli tick typhus rickettsia. We located three genes previously cloned and sequenced (genes encoding the R. rickettsii surface proteins of 120 and 190 kDa and the R. prowazekii citrate synthase gene), using Southern hybridization. The genes encoding citrate synthase and the surface protein of 190 kDa were usually located on the same band, and it is hypothesized that they are relatively close on the chromosome.

Chromosome Mapping↗
PubMed1993

Genotypic and antigenic identification of two new strains of spotted fever group rickettsiae isolated from China.

Four isolates of spotted fever group rickettsiae isolated from ticks in China were compared with all known species and strains of spotted fever group rickettsiae by immunofluorescence assay, DNA polymerase chain reaction followed by restriction endonuclease fragment length polymorphism analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western immunoblot. The Chinese isolates belonged to three types, including a novel serotype which has not been described before. One isolate obtained from tick ova of Dermacentor nuttallii in Inner Mongolia was antigenically and genotypically identical to Rickettsia sibirica. Two isolates obtained from Dermacentor sinicus collected from Beijing were identical, different from other members of spotted fever group rickettsiae but apparently closely related to R. sibirica. HA-91, a strain isolated from Hyalomma asiaticum bv. kozlovi olenew, was antigenically and genotypically unique among spotted fever group rickettsiae, and we feel that data presented here should prompt consideration of it as a new species on the basis of current rickettsial taxonomy.

Animals↗
PubMed1993

Proteinic and genomic identification of spotted fever group rickettsiae isolated in the former USSR.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), restriction fragment length polymorphism of polymerase chain reaction-amplified genes (RFLP-PCR), and pulsed-field gel electrophoresis (PFGE) were used to identify 25 isolates of spotted fever group rickettsia collected in the former USSR. Six Rickettsia akari isolates which were identical to the MK reference strain from the American Type Culture Collection were found. Also, 14 isolates were found to be Rickettsia sibirica and identical to reference strain 246. Two of three isolates previously considered as atypical, low-pathogenic strains of R. sibirica, were found to be strains of Rickettsia slovaca. The third, strain S, was similar in its RFLP-PCR profile to "R. africae" sp. nov. (proposed name for a rickettsia pathogenic for human beings in southern Africa) but in its SDS-PAGE and PFGE profiles was unique among spotted fever group rickettsiae. Strain M-1 was confirmed as a genetic variant of Rickettsia conorii. The Astrachan isolate, the causative agent of a tick-bite rickettsiosis at the North of the Caspian Sea, showed a previously described RFLP-PCR profile identical to that of the Israeli tick typhus rickettsia, but its SDS-PAGE and PFGE profiles different from those of the other strains tested.

Animals↗
PubMed1993

Detection of Ehrlichia chaffeensis in human tissue by using a species-specific monoclonal antibody.

A mouse monoclonal antibody (MAb 1A9) was produced and used in detection of Ehrlichia chaffeensis in human tissues including kidney, liver, and lung by using an indirect immunohistologic stain. MAb 1A9 was specific to E. chaffeensis and did not react with other bacteria, including Ehrlichia canis, which is the organism most closely related to E. chaffeensis. It reacted with an epitope present in two surface proteins of E. chaffeensis with molecular masses of 29 and 27 kDa. E. chaffeensis was easily detected in human tissue by immunohistology with MAb 1A9. This study demonstrates that our MAb can provide a specific and simple method for detection of E. chaffeensis in clinical specimens for establishing an etiologic diagnosis of human ehrlichiosis; it may also provide a tool for the investigation of immunopathologic characteristics in infected patients.

Animals↗
PubMed1993

Mediterranean spotted fever in Marseille, France: correlation between prevalence of hospitalized patients, seroepidemiology, and prevalence of infected ticks in three different areas.

We report the results of a comparison of several epidemiologic and ecologic parameters affecting the incidence and seroprevalence of Mediterranean spotted fever (MSF) in northern, central, and southeastern Marseille, an area endemic for this disease. In northern Marseille, the incidence of hospitalized patients with MSF was 24.2/100,000 persons compared with 9.8/100,000 and 8.8/100,000 for the central and southeastern regions, respectively. The seroprevalence in sera from blood donors, determined by microimmunofluorescence and confirmed by Western blot assays, was higher in the northern region than in the other two areas (6.7% versus 3.6% and 2.4%, respectively). This higher prevalence of MSF in the northern part of the city may be related to a greater tick exposure due to a higher number of dogs (32.6/100 inhabitants versus 28.4/100 and 27.2/100 in the central and southeastern regions, respectively) and a higher rate of infection of dogs in the northern region (51.4% versus 43.5% and 39.9%, respectively). The ratio of spotted fever group rickettsia-infected ticks was similar in both the northern and southeastern areas (14.8% and 13.4% respectively), but lower in the central area of the city (8.9%), leading to a higher risk of having MSF after a tick bite in the northern and southeastern parts of Marseille.

Adult↗
PubMed1993

First isolation of Rickettsia slovaca from Dermacentor marginatus in France.

Three rickettsial strains isolated from Dermacentor marginatus ticks in southern France in 1991 were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting with polyclonal mouse antisera, microimmunofluorescence serologic typing, and the polymerase chain reaction followed by analysis of restriction fragment length polymorphisms. By these methods, the isolates appear to be identical to the spotted fever group rickettsia, Rickettsia slovaca, which has so far been found only in Czechoslovakia. The fact that this rickettsial strain of unknown pathogenicity may occur in the same regions where R. conorii is endemic is of particular epidemiologic importance.

Animals↗
PubMed1993

Rickettsia conorii in Greece: comparison of a microimmunofluorescence assay and western blotting for seroepidemiology.

Since 1972, there have been no reports of Mediterranean spotted fever (MSF) in Greece. In 1991, a seroepidemiologic survey was conducted in three rural villages in the Province of Fokida in central Greece, using both an immunofluorescence assay (IFA) and Western blot to evaluate the prevalence of specific IgG and IgM antibodies to Rickettsia conorii, and to compare these two techniques. Of 254 sera tested by IFA, 148 (58.3%) were positive for IgG at a titer > or = 32 and 117 (46.1%) at a titer > or = 64. Two sera were positive for IgM at a titer > or = 32. Among the IFA-positive sera, 115 reacted against the specific protein antigen (SPA) using Western blotting and were considered as confirmed positive results, indicating a seroprevalence of 45.3%. Using the SPA reaction as a reference, the IFA diagnostic value of a single serum is poor in such an endemic area, suggesting the need for more specific tests. The results of this study have led us to conclude that for seroepidemiologic use, the IFA is not specific for MSF. Thus, the IFA is useful for sero-epidemiologic analysis only in areas where the true prevalence of MSF has been estimated using Western blotting.

Adult↗