Search PubMed⌕ Search

Biomedical subjects

D Raoult

Publications and source records attributed to D Raoult.

At least 253 records · Page 14Linked to original sources
PubMed1998

Molecular identification of Gemella species from three patients with endocarditis.

Gemella morbillorum and Gemella haemolysans are opportunistic pathogens which cause endocarditis and other severe infections. We report on three patients with endocarditis, one with endocarditis caused by G. haemolysans and two with endocarditis caused by G. morbillorum. The paucity of reports concerning these bacteria is probably related to the difficulties associated with their identification. For example, one of the strains reported in this study was originally sent to our laboratory with a preliminary characterization as a short "gram-negative" coccobacillus, highlighting the specific problem associated with Gram staining of these bacteria. The usefulness of 16S rRNA gene amplification, partial sequencing, and comparison of the nucleotide sequence to those in databases when standard phenotypic identification schemes are not helpful is emphasized. We also suggest that the use of simple tests, such as testing susceptibility to vancomycin for gram-negative bacteria and colistin for gram-positive bacteria, could prevent misinterpretation of Gram staining in gram-variable bacteria such as Gemella spp.

Aged↗
PubMed1998

Taxonomic relationships among spotted fever group rickettsiae as revealed by antigenic analysis with monoclonal antibodies.

The spotted fever group (SFG) is made up of more than 20 different rickettsial species and strains. Study of the taxonomic relationships among the group has been attempted by phenotypic, genotypic, and phylogenetic analyses. In this study, we determined taxonomic relationships among the SFG rickettsiae by comparative analysis of immunogenic epitopes reactive against a panel of monoclonal antibodies. A total of 98 monoclonal antibodies, which were directed against epitopes on the major immunodominant proteins or on the lipopolysaccharide-like antigens of strains of Rickettsia africae, Rickettsia conorii, Rickettsia massiliae, Rickettsia akari, Rickettsia sibirica, and Rickettsia slovaca, were used in the study. The distribution and expression of the epitopes among 29 SFG rickettsiae and Rickettsia bellii were assessed by determination of reaction titers in a microimmunofluorescence assay. The results were scored as numerical taxonomic data, and cluster analysis was used to construct a dendrogram. The architecture of this dendrogram was consistent with previous taxonomic studies, and the implications of this and other findings are discussed.

Antibodies, Monoclonal↗
PubMed1998

Isolation of Francisella tularensis by centrifugation of shell vial cell culture from an inoculation eschar.

A 52-year-old man was admitted to the hospital following the development of an inoculation eschar and fever six days after being bitten by a tick. He was clinically diagnosed as suffering from rickettsiosis. Eschar biopsy cultures on standard bacteriological media remained sterile. However, inoculation of cells with the homogenized specimen by the centrifugation-shell vial technique (M. Marrero and D. Raoult, Am. J. Trop. Med. Hyg. 40:197-199, 1989) resulted in the recovery of a bacterium. Determination of the sequence of the 16S rRNA gene amplified from the organism and comparison of the sequence to other sequences identified it as a strain of Francisella tularensis, whereas the specific serology was still negative. Our findings demonstrate that the centrifugation-cell culture, which is a tool for investigation of tick-transmitted diseases, may have the potential to serve as a method for the cultural isolation of F. tularensis.

Animals↗
PubMed1998

Lack of susceptibility of Ehrlichia canis to imidocarb dipropionate in vitro.

In vitro antimicrobial susceptibility testing was used to compare the efficacy of imidocarb dipropionate and doxycycline on the growth of Ehrlichia canis in DH82 cell cultures. Over a 9-day period there were no significant differences (p < 0.01) in the growth of E. canis in untreated control wells and those to which imidocarb dipropionate was added at 1.2, 2.4, 4.8 or 12 micrograms/ml for the 1st 3 days. Average infection rates rose from 50 to 55% on day 0 to 100% on day 5 or 6. Doxycycline at 1 microgram/ml had residual or rickettsiocidal activity against E. canis with the average percentages of DH82 cells infected declining from 51 to 24% while the organism was exposed to the drug (3 days) and from 21 to 2% in the 6 days following removal of the drug from the cell culture medium.

Animals↗
PubMed1998

Bartonella infections: diagnostic and management issues.

Bartonella species are emerging pathogens. Renewed interest in this group of bacteria has been highlighted by the recent description of new species, which are pathogenic for humans (Bartonella elizabethae and Bartonella clarridgeae), and their association with an increasing number of clinical manifestations, the more prevalent being cat scratch disease, bacillary angiomatosis, and culture-negative endocarditis.

Journal Article↗
PubMed1998

Spotted fever group rickettsiae in southern Africa--a review and current concepts.

Until recently our understanding of spotted fever group (SFG) rickettsioses in southern Africa was based on research carried out in the 1930s and 1940s. In the last decade there have been considerable advances in the techniques available to study rickettsias and the application of these in southern Africa has greatly increased our knowledge of the organisms in the region and the epidemiology of diseases they cause. In this review we describe the new advances used to study rickettsias and the current data available on SFG rickettsioses in the region.

Africa, Southern↗
PubMed1997

Prevalence of hepatitis G virus infection in kidney transplant recipients.

BACKGROUND: We investigated the prevalence, risk factors, and consequences of hepatitis G virus (HGV) infection in 87 kidney transplant recipients. METHODS: Infection was diagnosed with reverse transcriptase polymerase chain reaction using primers in the NS3 region of the viral genoma. RESULTS: Twenty-four patients (27.5%) were HGV RNA positive (HGV+ group) and 63 patients (72.5%) were HGV RNA negative (HGV- group). No statistically significant differences were found between the two groups for age, sex, transplantation and hemodialysis duration, number of kidney transplantations, serum creatinine, history of transfusions, hepatitis B and C virus infections, and percentage of patients having suffered from acute rejection. Acute and chronic hepatitis were not more prevalent in the HGV+ group than in the HGV- group. CONCLUSIONS: HGV infection is highly prevalent in kidney transplant recipients but does not alter liver or kidney functions. HGV contamination may be linked to nosocomial transmission during long-term hemodialysis.

Adult↗
PubMed1997

African tick-bite fever. An imported spotless rickettsiosis.

OBJECTIVES: To characterize the clinical presentation and course of African tick-bite fever, a recently rediscovered rickettsiosis caused by Rickettsia africae (a new species within the spotted fever group of rickettsiae), to establish its relationship with Amblyomma tick species, and to discuss its role in the etiology of fever in patients who are returning from the tropics. PATIENTS: Seven patients who returned from Zimbabwe of the Republic of South Africa and presented with fever. METHODS: Cases were recognized clinically by the presence of multiple taches noire and were diagnosed as having a rickettsial infection by identification of the organisms in circulating endothelial cells. The causative role of R africae was further demonstrated using cross-absorption and immunoblotting of patients' serum samples and isolation of the agent from blood and skin biopsy specimens. Isolates were characterized using the restriction fragment length polymorphism-polymerase chain reaction and sequence analysis of the gene that encodes for the 190-kd Rickettsia-specific antigen. RESULTS: All 7 patients presented with fever and multiple taches noire. Further physical examination of patients revealed lymphadenopathy, lymphangitis, and edema, but there were virtually no signs of a rash. These findings are characteristic of R africae-infected patients and are distinct from those observed in patients with Rickettsia conorii-induced Mediterranean spotted fever. All 7 patients were infected with R africae as demonstrated by immunoblotting or isolation of the agent, and all were cured. CONCLUSIONS: With increasing international travel, a need for the recognition of rickettsial diseases by physicians is becoming more important. Tick-bite fever, a disease caused by R africae and transmitted by Amblyomma ticks, is characterized by multiple taches noire, lymphadenopathy, lymphangitis, and edema, but no rash or a discrete rash. It is a frequent but benign disease that physicians should consider when presented with febrile patients returning from southern Africa.

Adult↗
PubMed1997

Current knowledge of Bartonella species.

Bartonella species are now considered emerging pathogens. Of the 11 currently recognized species, four have been implicated in human disease, although only two have been encountered in Europe. Bartonella quintana infections are now being diagnosed among the urban homeless and deprived, manifesting as trench fever, and Bartonella henselae has been shown to be the causative agent of cat scratch disease. Both species also cause a variety of HIV-associated infections, including bacillary anglomatosis. However, perhaps the most significant presentation of bartonellae infection is culture-negative endocarditis. The epidemiologies of Bartonella infections are poorly understood; most Bartonella henselae infections are probably acquired from infected cats, either directly by contact with a cat or indirectly via fleas. No animal reservoir has been implicated for Bartonella quintana; however, infection can be transmitted via the human body louse. Diagnosis of Bartonella infections can be made using histological or microbiological methods. The demonstration of specific antibodies may be useful in some instances, although certainly not in all. Cultivation of Bartonella is difficult, as the bacteria are extremely fastidious. Polymerase chain reaction-based or immunological methods for the detection of bartonella in infected tissues have proven useful. Clinical relapse is often associated with Bartonella infections despite a wide range of prescribed regimens. Only aminoglycosides display in vitro bactericidal activity against intracellular Bartonella species; therefore, they are recommended for treatment of Bartonella infections.

AIDS-Related Opportunistic Infections↗
PubMed1997

Prevalence and clinical significance of IgG isotype anti-beta 2-glycoprotein I antibodies in antiphospholipid syndrome: a comparative study with anticardiolipin antibodies.

To investigate the prevalence, significance, and specificity of IgG isotype anti-beta 2-Glycoprotein I antibodies (a-beta 2-GPI) in antiphospholipid syndrome (APS), we developed an enzyme-linked immunosorbent assay (ELISA) for the detection of IgG-a-beta 2-GPI and tested sera from 61 patients with autoimmune disorders (AID), 39 patients with APS and 22 patients with systemic lupus erythematosus without APS, 139 patients with various infectious diseases (hepatitis C virus infection, human immunodeficiency virus infection, Q fever, Mediterranean spotted fever, syphilis) and 97 healthy control subjects. Using irradiated plates coated with human beta 2-GPI, we showed that in the sera of patients with AID, optical densities from the coated wells were significantly higher than those from the noncoated ones (p = 0.0001). In this assay, intra-assay and inter-assay variation coefficients ranged between 4% and 10%. Clinical evaluation showed that IgG-a-beta 2-GPI were found in 23 of 61 patients with AID but in only one patient with an infectious disease. The presence of the IgG-a-beta 2-GPI in association with APS (p = 0.005) was statistically significant with high specificity (98%) and positive predictive value (87.5%) but with low sensitivity (54%), and was significantly associated with venous thrombosis (p = 0.0025). In addition, the IgG-a-beta 2-GPI levels were highly correlated with those of anticardiolipin antibodies (aCL) (p < 0.001). In contrast to a-beta 2-GPI, aCL were found with a high prevalence (40%) in patients with infectious diseases. Because of their high specificity, anti-beta 2-GPI antibodies appear to be useful tools in the evaluation of the risk of APS. However, because of their low sensitivity, their detection needs to be associated with that of aCL.

Adolescent↗
PubMed1997

Psoriasis is a risk factor for hip-prosthesis infection.

Risk factors for hip and knee prosthesis infection have been described, but not psoriasis. Eighty five infected patients from different centers and 202 non infected patients were included in a case-control study. Fifteen of 85 infected patients (17.6%), and 2 of 202 (1%) non infected patients had psoriasis. Odds ratio for infection in patients with psoriasis is 21.4 (4.7-195.5), and 39.7 (5.3-1718.8) in patients with hip prosthesis and psoriasis. No significant difference was found in patients with knee prosthesis. These data indicate that psoriasis is a risk factor for hip prostheses infection.

Case-Control Studies↗