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Biomedical subjects

D Raoult

Publications and source records attributed to D Raoult.

At least 163 records · Page 9Linked to original sources
PubMed1999

Q fever.

Q fever is a zoonosis with a worldwide distribution with the exception of New Zealand. The disease is caused by Coxiella burnetii, a strictly intracellular, gram-negative bacterium. Many species of mammals, birds, and ticks are reservoirs of C. burnetii in nature. C. burnetii infection is most often latent in animals, with persistent shedding of bacteria into the environment. However, in females intermittent high-level shedding occurs at the time of parturition, with millions of bacteria being released per gram of placenta. Humans are usually infected by contaminated aerosols from domestic animals, particularly after contact with parturient females and their birth products. Although often asymptomatic, Q fever may manifest in humans as an acute disease (mainly as a self-limited febrile illness, pneumonia, or hepatitis) or as a chronic disease (mainly endocarditis), especially in patients with previous valvulopathy and to a lesser extent in immunocompromised hosts and in pregnant women. Specific diagnosis of Q fever remains based upon serology. Immunoglobulin M (IgM) and IgG antiphase II antibodies are detected 2 to 3 weeks after infection with C. burnetii, whereas the presence of IgG antiphase I C. burnetii antibodies at titers of >/=1:800 by microimmunofluorescence is indicative of chronic Q fever. The tetracyclines are still considered the mainstay of antibiotic therapy of acute Q fever, whereas antibiotic combinations administered over prolonged periods are necessary to prevent relapses in Q fever endocarditis patients. Although the protective role of Q fever vaccination with whole-cell extracts has been established, the population which should be primarily vaccinated remains to be clearly identified. Vaccination should probably be considered in the population at high risk for Q fever endocarditis.

Animals↗
PubMed1999

Isolation of Rickettsia prowazekii from blood by shell vial cell culture.

A blood sample from a patient who returned from Algeria with a fever inoculated on human embryonic lung fibroblasts by the shell vial cell culture technique led to the recovery of Rickettsia prowazekii. The last clinical strain was isolated 30 years ago. Shell vial cell culture is a versatile method that could replace the classic animal and/or embryonated egg inoculation.

Aged↗
PubMed1999

Body lice as tools for diagnosis and surveillance of reemerging diseases.

Body lice are vectors of three bacteria which cause human disease: Rickettsia prowazekii, the agent of epidemic typhus; Bartonella quintana, the agent of trench fever; and Borrelia recurrentis, the agent of relapsing fever. A recrudescence of body lice is being observed as the numbers of individuals living under social conditions which predispose individuals to infestation have increased. Because this phenomenon may lead to the reemergence of infections transmitted by body lice, we aimed to assess the occurrence and prevalence of the three agents described above in more than 600 body lice collected from infested individuals in the African countries of Congo, Zimbabwe, and Burundi, in France, in Russia, and in Peru. The presence of the three bacteria in each louse was determined by specific PCR amplification, and the identities of the organisms detected were confirmed by determination of the nucleotide base sequences of the amplification products. Using this approach, we were able to confirm the presence of R. prowazekii in lice collected from refugees in Burundi, among whom typhus was epidemic, and the presence of B. quintana in lice collected from all locations except the Congo. B. recurrentis was never found. Molecular approaches are convenient tools for the detection and identification of bacterial DNA in body lice and for the epidemiological study of louse-borne bacteria from countries where no medical and biological laboratory facilities are available.

Animals↗
PubMed1999

Isolation of Legionella pneumophila by centrifugation of shell vial cell cultures from multiple liver and lung abscesses.

A 7-year-old girl was admitted to the hospital with acute lymphoblastic leukemia and was treated with allogenic cord blood transplantation. At day 30 after graft, she developed a fever and multiple nodular lesions disseminated in the liver and lungs. All bacterial cultures attempted on liver and lung biopsy specimens and blood remained sterile on standard axenic media. However, inoculation of liver and lung biopsy specimens on eukaryotic cell monolayers by the centrifugation-shell vial technique (M. Marrero and D. Raoult, Am. J. Trop. Med. Hyg. 40:197-199, 1989) led to the recovery of a strain of Legionella pneumophila serogroup 1, identified by 16S rRNA gene amplification and sequencing and serotyping. Our findings demonstrate that the centrifugation-cell culture method, which has previously been useful for the isolation of other strictly or facultatively intracellular bacteria, can also serve as a method for the recovery of L. pneumophila from clinical material.

Biopsy↗
PubMed1999

Culture of Bartonella quintana and Bartonella henselae from human samples: a 5-year experience (1993 to 1998).

Bartonella quintana and Bartonella henselae are fastidious gram-negative bacteria responsible for bacillary angiomatosis, trench fever, cat scratch disease, and endocarditis. During a 5-year period, we received 2,043 samples for culture of Bartonella sp. We found Bartonella sp. to be the etiologic agent in 38 cases of endocarditis, 78 cases of cat scratch disease, 16 cases of bacteremia in homeless people, and 7 cases of bacillary angiomatosis. We correlated the results of positive cultures with the clinical form of the disease, type of sample, culture procedure, PCR-based genomic detection, and antibody determination. Seventy-two isolates of B. quintana and nine isolates of B. henselae from 43 patients were obtained. Sixty-three of the B. quintana isolates and two of the B. henselae isolates, obtained from patients with no prior antibiotic therapy, were stably subcultured. The sensitivity of culture was low when compared with that of PCR-based detection methods in valves of patients with endocarditis (44 and 81%, respectively), skin biopsy samples of patients with bacillary angiomatosis (43 and 100%, respectively), and lymph nodes of cat scratch disease (13 and 30%, respectively). Serological diagnosis was also more sensitive in cases of endocarditis (97%) and cat scratch disease (90%). Among endocarditis patients, the sensitivity of the shell vial culture assay was 28% when inoculated with blood samples and 44% when inoculated with valvular biopsy samples, and the sensitivity of both was significantly higher than that of culture on agar (5% for blood [P = 0.045] and 4% for valve biopsy samples [P < 0.0005]). The most efficient culture procedure was the subculture of blood culture broth into shell vials (sensitivity, 71%). For patients with endocarditis, previous antibiotic therapy significantly affected results of blood culture; no patient who had been administered antibiotics yielded a positive blood culture, whereas 80% of patients with no previous antibiotic therapy yielded positive blood cultures (P = 0.0006). Previous antibiotic therapy did not, however, prevent isolation of Bartonella sp. from cardiac valves but did prevent the establishment of strains, as none of the 15 isolates from treated patients could be successfully subcultured. For the diagnosis of B. quintana bacteremia in homeless people, the efficiency of systematic subculture of blood culture broth onto agar was higher than that of direct blood plating (respective sensitivities, 98 and 10% [P < 10(-7)]). Nevertheless, both procedures are complementary, since when used together their sensitivity reached 100%. All homeless people with positive blood cultures had negative serology. The isolation rate of B. henselae from PCR-positive lymph nodes, in patients with cat scratch disease, was significantly lower than that from valves of endocarditis patients and skin biopsy samples from bacillary angiomatosis patients (13 and 33%, respectively [P = 0.084]). In cases of bacillary angiomatosis for which an agent was identified to species level, the isolation rate of B. henselae was lower than the isolation rate of B. quintana (28 and 64%, respectively [P = 0.003]). If culture is to be considered an efficient tool for the diagnosis of several Bartonella-related diseases, methodologies need to be improved, notably for the recovery of B. henselae from lymph nodes of patients with cat scratch disease.

Angiomatosis, Bacillary↗
PubMed1999

Isolation of Bartonella henselae from a serologically negative cat in Bloemfontein, South Africa.

Sera collected from apparently healthy 6-12-month-old cats (n = 31) presented to the Society for the Prevention of Cruelty to Animals Veterinary Clinic in Bloemfontein for neutering were tested for antibodies reactive to Bartonella henselae (Houston-1 strain) by indirect fluorescent antibody testing. Whole blood collected from the cats was used in isolation experiments and subsequent identification of Bartonella species was based on comparison of the nucleotide base sequence of polymerase chain reaction-amplified citrate synthase gene fragments. While none of the cats had antibodies reactive with B. henselae at titres > or =1/64, an organism with a partial citrate synthase gene sequence identical to that of B. henselae (Houston-1) was isolated from 1 cat.

Animals↗
PubMed1999

Survey of Bartonella species infecting intradomicillary animals in the Huayllacallán Valley, Ancash, Peru, a region endemic for human bartonellosis.

The natural cycle of Bartonella bacilliformis remains uncertain, and the suspected existence of animal reservoirs for the bacterium has never been convincingly demonstrated. We conducted a survey of Bartonella species infecting intradomicillary animals in a bartonellosis-endemic region of Peru, obtaining blood from 50 animals living in the homes of 11 families whose children had recently had bartonellosis. Bartonella-like bacteria were recovered from four of nine small rodents included in the study, but from none of the 41 domesticated animals. Identification and comparison of these isolates, and two Bartonella-like isolates obtained from Phyllotis mice in a different endemic region of Peru using serologic and genotypic methods indicated that although none were strains of B. bacilliformis, five were probably representatives of three previously unrecognized Bartonella species and one was a likely strain of the pathogenic species B. elizabethae.

Animals↗
PubMed1999

Imported African tick bite fever: a case report.

We describe a patient with African tick-bite fever who acquired his infection while visiting rural areas of South Africa and then became sick after returning to the United States. The dominant clinical feature of his illness was the presence of multiple, ulcerated lesions (tache noires). Physicians in the United States and other non-African countries who see travelers returning from southern parts of Africa who give a history of recent tick bite and/or present with multiple, crusted or vesicular skin lesions should be alert to this diagnosis and institute treatment with doxycycline.

Aged↗
PubMed1999

Tick-borne rickettiosis in Guadeloupe, the French West Indies: isolation of Rickettsia africae from Amblyomma variegatum ticks and serosurvey in humans, cattle, and goats.

Twenty-seven rickettsiae were isolated and/or detected from 100 Amblyomma variegatum ticks collected on Guadeloupe in the French West Indies. In this study, the polymerase chain reaction procedure appeared to be more sensitive in detecting rickettsiae in ticks than the shell-vial technique. Sequencing a portion of the outer membrane protein A-encoding gene showed that these rickettsiae appeared to be identical to Rickettsia africae, a member of the spotted fever group rickettsiae recently described as an agent of African tick-bite fever occurring in sub-Sahelian Africa. A high seroprevalence of antibodies to R. africae was demonstrated among mammals, particularly humans, cattle, and goats. These results and a recently reported case of an infection due to R. africae on Guadeloupe demonstrate that R. africae is present on this island. Although this disease has been underdiagnosed there, it may be frequent and may exist on other Caribbean islands where A. variegatum has propagated dramatically over recent years.

Adolescent↗
PubMed1999

[Epidemic typhus in Africa].

Epidemic typhus is caused by a small strictly intracellular virus named Rickettsia prowazekii, a member of the Rickettsial family. It is transmitted to man by the body louse, Pediculus humanus. Although now rare in Western countries, exanthematic typhus remains common in the Southern hemisphere due to poverty, inadequate clothing hygiene, and poor socioeconomic conditions. In Africa, outbreaks have historically occurred in Burundi, Rwanda, southwest Ouganda, and Ethiopia. The largest outbreak of epidemic typhus since the World War II was reported in Burundi where ongoing civil war since October 1993 has forced 10 p. 100 of the population of Burundi to live in cold, promiscuity, and malnutrition of makeshift refugee camps. The purpose of this report based on our two-year experience working with this unfortunate population is to describe the characteristics of this disease in Africa where the epidemic form had become rare until recently. Indeed political unrest as well as numerous civil wars are now epidmiological factors favorizing outbreaks of epidemic typhus at any time. This overview also provides an opportunity to recall epidemiological, bacteriological, and clinical aspects of typhus as well as diagnosis and treatment of the disease in the context of Africa.

Africa↗
PubMed1999

Differences in levels of soluble E-selectin and VCAM-1 in malignant versus non malignant Mediterranean spotted fever.

In the present study, we investigated the plasma levels of soluble adhesion molecules E-selectin, P-selectin, intercellular adhesion molecule- (ICAM- ) and vascular cell adhesion molecule-1(VCAM-1) in 24 patients with Mediterranean spotted fever (MSF), 6 of whom with a malignant form. Measurements were performed on blood samples collected before treatment (T1), then twice during treatment (T2 and T3). Before treatment, MSF patients taken as a whole presented elevated levels of sICAM-1 and sVCAM-1 and normal levels of sE-selectin and sP-selectin compared to healthy controls. We found that sICAM-1 was elevated both in mild and malignant MSF. sE-selectin and sVCAM-1 were elevated only in patients with the malignant form and allowed to discriminate the two clinical subgroups. Their levels decreased after treatment with sE-selectin reaching control values at T2 whereas sVCAM-1 remained higher over the course of the malignant form. In patients with mild MSF, sP-selectin steadily increased after treatment, whereas it did not present any modification at any of the two sampling times in patients with the malignant form. Raised plasma levels of sE-selectin and sVCAM-1 reflect endothelial activation in malignant rickettsial disease and may be sufficiently early markers to influence the therapeutic decision.

Adult↗
PubMed1998

Detection of 400-year-old Yersinia pestis DNA in human dental pulp: an approach to the diagnosis of ancient septicemia.

Ancient septicemic plague epidemics were reported to have killed millions of people for 2 millenniums. However, confident diagnosis of ancient septicemia solely on the basis of historical clinical observations is not possible. The lack of suitable infected material has prevented direct demonstration of ancient septicemia; thus, the history of most infections such as plague remains hypothetical. The durability of dental pulp, together with its natural sterility, makes it a suitable material on which to base such research. We hypothesized that it would be a lasting refuge for Yersinia pestis, the plague agent. DNA extracts were made from the dental pulp of 12 unerupted teeth extracted from skeletons excavated from 16th and 18th century French graves of persons thought to have died of plague ("plague teeth") and from 7 ancient negative control teeth. PCRs incorporating ancient DNA extracts and primers specific for the human beta-globin gene demonstrated the absence of inhibitors in these preparations. The incorporation of primers specific for Y. pestis rpoB (the RNA polymerase beta-subunit-encoding gene) and the recognized virulence-associated pla (the plasminogen activator-encoding gene) repeatedly yielded products that had a nucleotide sequence indistinguishable from that of modern day isolates of the bacterium. The specific pla sequence was obtained from 6 of 12 plague skeleton teeth but 0 of 7 negative controls (P < 0.034, Fisher exact test). A nucleic acid-based confirmation of ancient plague was achieved for historically identified victims, and we have confirmed the presence of the disease at the end of 16th century in France. Dental pulp is an attractive target in the quest to determine the etiology of septicemic illnesses detected in ancient corpses. Molecular techniques could be applied to this material to resolve historical outbreaks.

Base Sequence↗
PubMed1998

Bacillary angiomatosis in immunocompromised patients.

OBJECTIVES: To report seven cases of bacillary angiomatosis; to evaluate the most useful diagnostic tools; to analyse the clinical and epidemiological features associated with Bartonella quintana or Bartonella henselae infections. DESIGN: Clinical, diagnostic and epidemiological evaluation of 37 speciated bacillary angiomatosis cases in the literature, including the seven patients in our study. METHODS: Pathological examination of tissue samples, including Warthin-Starry staining and immunohistology; titre of antibodies to Bartonella sp.; detection of Bartonella sp. in blood and biopsy materials by culture or PCR; and statistical analysis of clinical and epidemiological features associated with B. quintana or B. henselae bacillary angiomatosis cases. RESULTS: Seven immunocompromised patients (six with AIDS and one patient with acute leukaemia) had bacillary angiomatosis confirmed by histology. B. quintana was cultured in three patients, whereas B. henselae DNA was amplified by PCR in the remaining four patients. Serum from only one patient reacted with Bartonella antigens. Amongst the 14 B. quintana and 23 B. henselae bacillary angiomatosis cases now reported in the literature, lymphadenopathies were significantly more frequent in B. henselae-infected patients, and neurological disorders of the central nervous system in B. quintana-infected patients. Risk factors were contact with cats, and homelessness or poor socioeconomic status in B. henselae and B. quintana bacillary angiomatosis cases, respectively. CONCLUSIONS: Although diagnosis of bacillary angiomatosis often remains solely based upon histology, culture or PCR-based methods are useful for the detection of Bartonella sp., and allow identification of the species involved, which is necessary to further characterize clinical and epidemiological features associated with B. quintana or B. henselae infections.

AIDS-Related Opportunistic Infections↗
PubMed1998

Outbreak of epidemic typhus associated with trench fever in Burundi.

BACKGROUND: After a 12-year absence, epidemic typhus has re-emerged among the displaced population of Burundi. Following the outbreak of civil war in 1993, over 760000 people now inhabit refugee camps, under appalling conditions. A typhus outbreak occurred among prisoners in a jail in N'Gozi in 1995. At the time, the disease was not recognised, and was referred to as sutama. Reports of sutama among the civilian population date back to late 1995 and, in association with body-louse infestation, the disease has subsequently swept across the higher and colder regions of the country. METHODS: During a field study in February, 1997, 102 refugees with sutama underwent clinical examination and interview. Serum samples were collected and infesting body lice removed. Microbiological analysis included antibody estimations and specific PCRs aimed at diagnosis of Rickettsia prowezekii, Bartonella quintana, and Borrelia recurrentis. Between January and September, 1997, nationwide epidemiological data on the prevalence and distribution of sutama was obtained through liaison with local health services. A second field study in March, 1997, entailed the collection of further serum samples from suspected cases of sutama in different regions of Burundi. FINDINGS: Most of the 102 patients with sutama during initial assessment presented with manifestations similar to those previously described for typhus in Africa, though skin eruptions occurred in only 25 (25%) cases. Microbiological testing revealed evidence of R prowazeki infection in 76 (75%) patients, confirming that most cases of clinically-diagnosed sutama were epidemic typhus, and supporting the reliability of clinical diagnosis as a basis for the nationwide surveillance of the disease. Up to September, 1997, 45558 typhus cases were clinically diagnosed, most of which occurred in regions at an altitude of over 1500 m. Serological testing of 232 individuals from different regions of Burundi provided microbiological evidence to support clinical diagnoses in seven provinces, confirming the widespread nature of the outbreak. Serum from 13 of the original 102 patients and 19 (8%) of the 232 suspected cases had raised antibody titres against B quintana. A fatality rate of 15% among jail inmates fell to 0.5% after administration of a single dose of 200 mg doxycycline to suspected cases. INTERPRETATION: A gigantic outbreak of R prowazekii-induced typhus and B quintana-induced trench fever is continuing in Burundi. Transmission of both diseases to such a large number of people has followed a widespread epidemic of body-louse infestation. Diagnosis of typhus could be reliably made by means of clinical criteria, and the disease could be efficiently and easily treated by antibiotics. This epidemic highlights the appalling conditions in central-African refugee camps and the failure of public-health programmes to serve their inhabitants. Louse-associated disease remains a major health threat in this and other war-torn regions of the world.

Anti-Bacterial Agents↗