Biomedical subjects
Publications and source records attributed to Jean-Marc Rolain.
To investigate the presence of rickettsioses in rural residents of the central Thai-Myanmar border, we tested the blood of 46 patients with fever. Four patients had murine typhus, three patients had scrub typhus, and eight patients had spotted fever group rickettsioses, including the first case of Rickettsia felis infection reported in Asia.
Bartonella quintana is transmitted by body lice among homeless people. Infection with this organism leads to chronic bacteraemia with few symptoms. We looked for B quintana in erythrocytes in a population of homeless people in Marseille, France. In this report we show the intraerythrocytic presence of B quintana in people with symptomless bacteraemia, by use of a specific monoclonal antibody and laser confocal microscopy. Presence of at least 5 x 10(4) colony-forming units per mL was predictive of intracellular infection. However, such infection was not associated with evidence of haemolysis. Colonisation of erythrocytes could allow efficient transmission of B quintana by body lice.
On the basis of phenotypic data obtained on the strain Marseille-URRWFXCal2(T), isolated from the cat flea Ctenocephalides felis, the description of Rickettsia felis (Bouyer et al., 2001) is emended and Marseille-URRWFXCal2(T) is proposed as the type strain of the species. On the basis of polyphasic characterization, especially the inability to grow at temperatures higher than 32 degrees C on Vero cells that allow growth of other Rickettsia to at least 35 degrees C, it is confirmed that this agent, although different from other recognized rickettsial species, is genotypically indistinguishable from bacteria previously detected within cat fleas and provisionally named ELB. Comparison of the phenotypic characteristics previously described for R. felis and those observed for the isolate in this study indicated some differences, although concurrent analysis of the two was not possible as no extant isolates of the first isolate of R. felis exist.
Rickettsiae grow only intracellularly, and the antibiotic susceptibilities of these bacteria have been assessed by either plaque, dye uptake, or immunofluorescence assays, which are time-consuming. We used a quantitative PCR (with the LightCycler instrument) to assess the levels of inhibition of Rickettisa felis, R. conorii, and R. typhi DNA synthesis in the presence of various antibiotics. We established the kinetics of rickettsial DNA during growth and showed that R. conorii grows more quickly than R. typhi in cell culture, with maximum replication occurring after 5 and 7 days, respectively. The MICs of the antibiotics tested for R. conorii and R. typhi by the quantitative PCR assay were similar to those previously obtained by plaque and dye uptake assays. We found that R. felis is susceptible to doxycycline, rifampin, thiamphenicol, and fluoroquinolones but not to gentamicin, erythromycin, amoxicillin, or trimethoprim-sulfamethoxazole. The resistance of this new species to erythromycin is consistent with its current taxonomic position within the spotted fever group. We believe that quantitative PCR could be used in the future to simplify and shorten antibiotic susceptibility assays of other rickettsiae and other strict intracellular pathogens.
Between the dates of May 4th-August 6th 2002, 46 cases were detected with abdominal pain nausea, vomiting, arthralgia/myalgia, headache, fever, diarrhea and rash, in the middle Blacksea and north inner Anatolia regions. Their laboratory findings yielded elevated levels of liver enzymes (AST, ALT, LDH), leucopenia and thrombocytopenia. As the infection was treated easily with tetracyclines, clinical diagnosis was considered to be rickettsiosis or ehrlichiosis. Serum and blood samples obtained from some of the patients were tested against Rickettsia, Ehrlichia, Leptospira and Coxiella, in the national and international laboratories. Samples from 19 patients were sent to National Reference Centre and WHO Collaborating Centre for Rickettsial Reference and Research Laboratory, France, and 7 of them were reported as acute Q fever while 8 of them were reported as passed Q fever (QF) cases. In May 2003, new cases with similar symptoms have been reported from the same regions, with different epidemiologic and serologic findings (tick exposure history was higher, response to tetracycline was lower, C. burnetii antibodies were negative), indicating a viral etiology. The samples of these patients have been sent to National Reference Centre and WHO Collaborating Centre for Arboviruses and Viral Heamorrhagic Fevers, France, and the initial reports were marked as Crimean Congo hemorrhagic fever virus (CCHFV). Then the serum samples of previous 26 patients which were stored in National Serum Bank have been retrospectively investigated for viral aetiology in the same center, and 17 of them have been found positive for CCHFV IgM antibodies. Four of these patients were diagnosed as acute QF in 2002, one was passed QF, 2 were negative for QF and 10 were patients not investigated for QF. As a result, the detection of the both infections together in the same area shows the essential need for further epidemiological investigations.