Endocardite infecciosa é uma doença associada à elevada morbidade e letalidade. O diagnóstico precoce e o reconhecimento de sua etiologia podem contribuir para o sucesso do tratamento antibiótico; entretanto, cerca de um quarto das endocardites permanece sem diagnóstico etiológico. Este estudo teve como objetivo principal identificar a frequência de endocardite por Bartonella spp. e Coxiella burnetii dentre as endocardites com culturas negativas comunitárias e avaliar os fatores preditores dessas infecções. Como objetivo secundário compararam-se as características clínicolaboratoriais e prognósticas entre as endocardites comunitárias com culturas negativas e positivas. Foram avaliados também os fatores associados à letalidade intra-hospitalar das endocardites com culturas negativas. Entre janeiro de 2004 e janeiro de 2009, foram investigados 369 episódios consecutivos de endocardite em pacientes atendidos no Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - InCor HC-FMUSP. Foram estudados os casos que ocorreram em adultos, classificados pelos critérios de Duke modificados como \"endocardite definida\" e de origem comunitária. Assim, foram incluídos 221 episódios de endocardite, 170 com culturas positivas e 51 com culturas negativas. Neste último grupo, foram feitas as pesquisas sorológicas (reação de imunofluorescência indireta) e histopatológica de Bartonella spp. e Coxiella burnetii. Consideraram-se positivos títulos de imunoglobulina G (IgG) >= 800 para Bartonella henselae e ou Bartonella quintana, e IgG antifase I para C. burnetii > 800. O estudo histopatológico das valvas cardíacas foi capaz de identificar morfologicamente a etiologia de 87% das endocardites com culturas negativas, enquanto que o método de Gram do tecido a fresco o fez em somente 10% dos casos. As endocardites com culturas negativas apresentaram maior frequência de dispneia à admissão (p=0,001), menor valor de proteína C reativa (p=0,009), menor Fração de Ejeção do Ventrículo Esquerdo (Feve) (p=0,022) e necessitaram de mais tempo para o início do tratamento antibiótico para endocardite (p < 0,001) quando comparadas àquelas com culturas positivas. Não houve diferença estatisticamente significante entre os grupos na letalidade intra-hospitalar e na sobrevida após alta hospitalar. Verificou-se que a presença de diabetes mellitus (p=0,009) ou sepse grave na admissão (p=0,01) esteve independentemente associada ao óbito intra-hospitalar entre as endocardites com culturas negativas. Dez casos de endocardite por Bartonella spp. (frequência 19,6% [IC95%: 9,8 - 33,1]) e quatro casos de endocardite por Coxiella burnetii (frequência 7,8% [IC95%: 2,2 - 18,9]) foram diagnosticados dentre os 51 episódios de endocardite com culturas negativas. As endocardites por Bartonella spp. apresentavam menor Feve (p=0,025), associação com a identificação de cocobacilo Gram-negativo no exame histológico da valva cardíaca (p=0,001) e presença de gato no domicílio (p=0,001). Conclusões: Bartonella spp. e Coxiella burnetii foram as etiologias de quase um terço (27,5%) das endocardites comunitárias com culturas negativas. A presença de gato no domicílio, Feve <= 45%, e a identificação de cocobacilo Gramnegativo no exame histológico da valva cardíaca em pacientes com endocardite com culturas negativas parecem estar associadas à infecção por Bartonella spp. O exame histológico da valva cardíaca permitiu a identificação morfológica do micro-organismo na maioria dos casos, mesmo quando as hemoculturas estavam negativas. Não se observou diferença na letalidade intra-hospitalar e na sobrevida em longo prazo entre os dois grupos. A presença de diabetes mellitus ou sepse grave à admissão associou-se ao óbito hospitalar nas endocardites com culturas negativas / Infective endocarditis is associated with high morbidity and lethality. Early diagnosis and recognition of the specific etiology can contribute to successful antibiotic treatment. However, approximately one-fourth of endocarditis cases remain without an etiologic diagnosis. This study aimed to identify the frequency of endocarditis caused by Bartonella spp. and Coxiella burnetii among cases of community-acquired culture-negative endocarditis and to also assess risk factors for such infections. As a secondary objective, the clinical, laboratory and prognostic features of community-acquired endocarditis were compared. Factors related to the in-hospital lethality of culture-negative endocarditis were also assessed. Between January 2004 and January 2009, 369 consecutive cases of endocarditis were investigated in patients attending the no Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - InCor HC-FMUSP. Cases occurring in adults, those classified by the modified Duke criteria as \"defined endocarditis\" and community-acquired cases were studied. In total, 221 cases of endocarditis comprising 170 culture-positive and 51 culturenegative cases were included. For the culture-negative cases, serology (indirect immunofluorescence reaction) and histopathological analyses for Bartonella spp. and Coxiella burnetii were performed. Cases were considered positive for Bartonella henselae or Bartonella quintana with IgG titers >= 800 and for Coxiella burnetii with antiphase I IgG titers > 800. Histopathological studies of the cardiac valves were capable of morphologically identifying the etiology in 87% of the culture-negative endocarditis cases, whereas the Gram stain was only positive in 10% of cases using fresh tissue. Culture-negative endocarditis patients presented a greater frequency of dyspnea on admission (p=0.001), lower C-reactive protein levels (p=0.009), and a lower left ventricular ejection fraction (LVEF) (p=0.022), and they required more time to start antibiotic therapy (p < 0.001) when compared with culture-positive patients. There was no statistically significant difference between the two groups regarding in-hospital lethality or survival after hospital discharge. Diabetes mellitus (p=0.01) or severe sepsis on admission (p=0.01) were independently associated with in-hospital death for culture-negative endocarditis. Ten cases of endocarditis caused by Bartonella spp. (frequency 19.6% [IC95%: 9.8 - 33.1]) and 4 caused by Coxiella burnetii (frequency 7.8% [IC95%: 2.2 - 18.9]) were diagnosed among the 51 cases of culture-negative endocarditis. Endocarditis caused by Bartonella spp. was associated with lower LVEF values (p=0.025), the identification of Gram-negative coccobacilli in cardiac valve histology (p=0.001) and the presence of a cat in the patient\'s residence (p=0.001). Conclusions: Bartonella spp. and Coxiella burnetii were the causative etiology of almost one-third (27.5%) of the community-acquired cases of culture-negative endocarditis. The presence of a cat in the patient\'s residence, a LVEF <= 45% and the identification of Gram-negative coccobacilli in the histological examination of the cardiac valve in patients with culturenegative endocarditis appear to be associated with Bartonella spp. as the causative etiology. Histological examination of the cardiac valves allowed for morphological identification of the causative microorganism in the majority of cases, even when blood cultures were negative. There was no difference in in-hospital lethality or long-term survival between the two groups. The presence of diabetes mellitus or severe sepsis at admission was associated with in-hospital death in cases of culture-negative endocarditis

Bartoneloses são infecções causadas por Bartonella spp e constituem zoonoses de importância crescente devido à gravidade da infecção em pacientes imunodeficientes. Existem muitas síndromes clínicas associadas às bartoneloses, desde quadros típicos de doença da arranhadura do gato até lesões cutâneas linfoproliferativas (angiomatose bacilar), ou granulomatosas em órgãos (peliose bacilar), passando por quadros neurológicos, oculares, endocardites e febre prolongada. O diagnóstico laboratorial deveria ser baseado em isolamento da bactéria em cultura, resultados de sorologias e exames imunohistoquímicos, porém estas técnicas não se encontram disponíveis em nosso meio. A Reação da Cadeia da Polimerase (PCR) tem sido utilizada para aprimorar o diagnóstico das bartoneloses, e o presente estudo teve como objetivo padronizar três sistemas de dupla amplificação para detecção de DNA de Bartonella henselae em amostras biológicas de pacientes com suspeita de bartonelose e determinar dentre os sistemas de dupla amplificação (nested-PCR), aquele com melhor desempenho. Os nested-PCR empregaram oligonucleotídeosiniciadores das sequências ITS, HSP e FtsZ da Bartonella spp. Foram incluídos 19 pacientes, sendo 14 crianças/adolescentes e cinco adultos, tendo oito deles referido contato com gatos. Dos pacientes, 10 não tinham doenças de base, e nove apresentavam doença de base (três evoluíram a óbito). Foram coletadas 25 amostras: 14 de sangue periférico, sete biópsias de gânglios, duas punções de gânglios e duas biópsias de pele. Do total de 19 pacientes, 14 tiveram resultados positivos por PCR, e considerando as 25 amostras, 18 foram positivas por PCR (nove amostras de sangue, cinco biópsias de gânglios, duas punções de gânglios e duas biópsias de pele). Dez das 18 amostras positivas por PCR só foram detectadas pelo nested-FtsZ (seis amostras de sangue periférico, duas punções de gânglios, uma biópsia de gânglio e uma biópsia de pele). A primeira amplificação do sistema HSP-PCR detectou uma amostra positiva em 25 (1/25 ou 4%), e após o nested-HSP este percentual foi de 24% (6/25). Na primeira amplificação do sistema ITS-PCR a positividade foi de 20% (5/25), e no nested-ITS 32% (8/25). Após a primeira amplificação do sistema FtsZ-PCR a positividade foi de 16% (4/25), e no nested-FtsZ foi de 72% (18/25). O teste de McNemar testou a concordância ou discordância dos resultados obtidos pelos três sistemas de nested-PCR e revelou que os mesmos foram discordantes, com superioridade do sistema nested-FtsZ em relação aos outros dois nested-PCR, sendo a diferença estatisticamente significante (p<0,05). Os resultados do presente estudo permitiram concluir que o nested-FtsZ apresentou vantagens para o diagnóstico das bartoneloses em relação aos outros sistemas testados, em materiais biológicos previamentedescritos na literatura (biópsias e punções de gânglios), e até mesmo em sangue periférico de pacientes sem doença de base. Além disso, foi possível determinar, no presente estudo, que as infecções foram causadas por B. henselae, uma vez que não houve nenhuma PCR positiva pelos outros dois sistemas que não tenha sido detectada pelo nested-FstZ, e este amplifica apenas DNA de Bartonella henselae após a segunda amplificação. / Bartonellosis are infections caused by Bartonella spp and this zoonosis is of growing importance due to the severity of infection in immunodeficient patients. Many clinical syndromes are associated with bartonellosis, varying from typical manifestations of cat scratch disease, to lymphoproliferative skin lesions (bacillary angiomatosis) or granulomatous ones in organs (bacillary peliosis), and also neurologic and ocular manifestations, endocarditis and prolonged fever. The laboratory diagnosis should be based on bacteria isolation in culture, serological tests and immunohistochemical examination, but these techniques are not available in our country. The Polymerase Chain Reaction (PCR) has been used to improve the diagnosis of bartonellosis, and this study has aimed at standardizing three nested-amplifications for detection of Bartonella henselae DNA in biological samples of patients with suspected bartonellosis, and establishing among the three nested-PCR, the one presenting with the best performance. Nested-PCR amplifications were performed using the ITS, the HSP and the FtsZ gene sequences of Bartonella spp. We included 19 patients, being 14 children / adolescents andfive adults, and eight reported contact with cats. From these patients, 10 had no underlying disease, and nine patients had underlying conditions (3 evolved to death). We collected 25 samples: 14 peripheral blood samples, seven lymph nodes biopsies, two lymph nodes punctures and two skin biopsies. From the total of 19 patients, 14 had positive results by PCR, and considering the 25 samples, 18 were positive by PCR (nine peripheral blood samples, five lymph nodes biopsies, two lymph nodes punctures and two skin biopsies). Ten of the 18 PCR-positive samples were only detected by the nested-FtsZ (six peripheral blood samples, two lymph nodes punctures, one lymph node biopsy and one skin biopsy). The first HSP-PCR amplification detected one positive sample in 25 (1 / 25 or 4%), and after the nested-HSP this percentage was 24% (6 / 25). In the first ITS-PCR amplification the positivity was 20% (5 / 25), and after the nested-ITS 32% (8 / 25). The first FtsZ-PCR amplification positivity was 16% (4 / 25), and after the nested-FtsZ it was 72% (18/25). The McNemar test was used to verify the concordance or discordance of the results obtained by the three nested-PCR systems and showed that they were discordant, with superiority of the nested-FtsZ in relation to the other two nested-PCR, being the difference statistically significant (p<0.05). The results of this study indicated that the nested-FtsZ showed advantages for the diagnosis of bartonellosis with respect to the other two systems when biological materials previously described in literature were tested (punctures and lymph nodes biopsies), and also in peripheral blood of patients without underlying conditions. Furthermore, it was possible to determine that the infections were caused byB. henselae, since there was no positive PCR results obtained by the other two systems that were not detected by the nested-FstZ, that only amplifies DNA from Bartonella henselae after the second round of amplification.

Bartoneloses são infecções causadas por Bartonella spp e constituem zoonoses de importância crescente devido à gravidade da infecção em pacientes imunodeficientes. Existem muitas síndromes clínicas associadas às bartoneloses, desde quadros típicos de doença da arranhadura do gato até lesões cutâneas linfoproliferativas (angiomatose bacilar), ou granulomatosas em órgãos (peliose bacilar), passando por quadros neurológicos, oculares, endocardites e febre prolongada. O diagnóstico laboratorial deveria ser baseado em isolamento da bactéria em cultura, resultados de sorologias e exames imunohistoquímicos, porém estas técnicas não se encontram disponíveis em nosso meio. A Reação da Cadeia da Polimerase (PCR) tem sido utilizada para aprimorar o diagnóstico das bartoneloses, e o presente estudo teve como objetivo padronizar três sistemas de dupla amplificação para detecção de DNA de Bartonella henselae em amostras biológicas de pacientes com suspeita de bartonelose e determinar dentre os sistemas de dupla amplificação (nested-PCR), aquele com melhor desempenho. Os nested-PCR empregaram oligonucleotídeosiniciadores das sequências ITS, HSP e FtsZ da Bartonella spp. Foram incluídos 19 pacientes, sendo 14 crianças/adolescentes e cinco adultos, tendo oito deles referido contato com gatos. Dos pacientes, 10 não tinham doenças de base, e nove apresentavam doença de base (três evoluíram a óbito). Foram coletadas 25 amostras: 14 de sangue periférico, sete biópsias de gânglios, duas punções de gânglios e duas biópsias de pele. Do total de 19 pacientes, 14 tiveram resultados positivos por PCR, e considerando as 25 amostras, 18 foram positivas por PCR (nove amostras de sangue, cinco biópsias de gânglios, duas punções de gânglios e duas biópsias de pele). Dez das 18 amostras positivas por PCR só foram detectadas pelo nested-FtsZ (seis amostras de sangue periférico, duas punções de gânglios, uma biópsia de gânglio e uma biópsia de pele). A primeira amplificação do sistema HSP-PCR detectou uma amostra positiva em 25 (1/25 ou 4%), e após o nested-HSP este percentual foi de 24% (6/25). Na primeira amplificação do sistema ITS-PCR a positividade foi de 20% (5/25), e no nested-ITS 32% (8/25). Após a primeira amplificação do sistema FtsZ-PCR a positividade foi de 16% (4/25), e no nested-FtsZ foi de 72% (18/25). O teste de McNemar testou a concordância ou discordância dos resultados obtidos pelos três sistemas de nested-PCR e revelou que os mesmos foram discordantes, com superioridade do sistema nested-FtsZ em relação aos outros dois nested-PCR, sendo a diferença estatisticamente significante (p<0,05). Os resultados do presente estudo permitiram concluir que o nested-FtsZ apresentou vantagens para o diagnóstico das bartoneloses em relação aos outros sistemas testados, em materiais biológicos previamentedescritos na literatura (biópsias e punções de gânglios), e até mesmo em sangue periférico de pacientes sem doença de base. Além disso, foi possível determinar, no presente estudo, que as infecções foram causadas por B. henselae, uma vez que não houve nenhuma PCR positiva pelos outros dois sistemas que não tenha sido detectada pelo nested-FstZ, e este amplifica apenas DNA de Bartonella henselae após a segunda amplificação. / Bartonellosis are infections caused by Bartonella spp and this zoonosis is of growing importance due to the severity of infection in immunodeficient patients. Many clinical syndromes are associated with bartonellosis, varying from typical manifestations of cat scratch disease, to lymphoproliferative skin lesions (bacillary angiomatosis) or granulomatous ones in organs (bacillary peliosis), and also neurologic and ocular manifestations, endocarditis and prolonged fever. The laboratory diagnosis should be based on bacteria isolation in culture, serological tests and immunohistochemical examination, but these techniques are not available in our country. The Polymerase Chain Reaction (PCR) has been used to improve the diagnosis of bartonellosis, and this study has aimed at standardizing three nested-amplifications for detection of Bartonella henselae DNA in biological samples of patients with suspected bartonellosis, and establishing among the three nested-PCR, the one presenting with the best performance. Nested-PCR amplifications were performed using the ITS, the HSP and the FtsZ gene sequences of Bartonella spp. We included 19 patients, being 14 children / adolescents andfive adults, and eight reported contact with cats. From these patients, 10 had no underlying disease, and nine patients had underlying conditions (3 evolved to death). We collected 25 samples: 14 peripheral blood samples, seven lymph nodes biopsies, two lymph nodes punctures and two skin biopsies. From the total of 19 patients, 14 had positive results by PCR, and considering the 25 samples, 18 were positive by PCR (nine peripheral blood samples, five lymph nodes biopsies, two lymph nodes punctures and two skin biopsies). Ten of the 18 PCR-positive samples were only detected by the nested-FtsZ (six peripheral blood samples, two lymph nodes punctures, one lymph node biopsy and one skin biopsy). The first HSP-PCR amplification detected one positive sample in 25 (1 / 25 or 4%), and after the nested-HSP this percentage was 24% (6 / 25). In the first ITS-PCR amplification the positivity was 20% (5 / 25), and after the nested-ITS 32% (8 / 25). The first FtsZ-PCR amplification positivity was 16% (4 / 25), and after the nested-FtsZ it was 72% (18/25). The McNemar test was used to verify the concordance or discordance of the results obtained by the three nested-PCR systems and showed that they were discordant, with superiority of the nested-FtsZ in relation to the other two nested-PCR, being the difference statistically significant (p<0.05). The results of this study indicated that the nested-FtsZ showed advantages for the diagnosis of bartonellosis with respect to the other two systems when biological materials previously described in literature were tested (punctures and lymph nodes biopsies), and also in peripheral blood of patients without underlying conditions. Furthermore, it was possible to determine that the infections were caused byB. henselae, since there was no positive PCR results obtained by the other two systems that were not detected by the nested-FstZ, that only amplifies DNA from Bartonella henselae after the second round of amplification.

Universiẗat, Diss., 2006--Giessen.

Zugl.: Giessen, Univ., Diss., 2006

Universiẗat, Diss., 2005--Leipzig. / Dateiformat: zip, Datei im PDF-Format.

Infective endocarditis due to Bartonella bacilliformis is rare. A 64-year-old woman, without previous heart disease, presented with 6 weeks of fever, myalgias, and arthralgias. A systolic murmur was heard on the tricuspid area upon examination, and an echocardiogram showed endocardial lesions in the right atrium. Bartonella bacilliformis was isolated in blood cultures, defining the diagnosis of infective endocarditis using Duke’s criteria. Subsequently, the patient developed clinical and laboratory features compatible with antineutrophil cytoplasmic antibody-associated vasculitis. This case presents an uncommon complication of B. bacilliformis infection associated with the development of systemic vasculitis.

Objective This study investigated an outbreak of Bartonellosis in a coastal region in Peru. Results A total of 70 (n = 70) samples with clinical criteria for the acute phase of Bartonellosis and a positive peripheral blood smear were included. 22.85% (n = 16) cases of the samples were positive for Bartonella bacilliformis by PCR and automatic sequencing. Of those positive samples, 62.5% (n = 10) cases were positive only for B. bacilliformis and 37.5% (n = 6) cases were positive to both Mycobacterium spp. and B. bacilliformis. The symptom frequencies were similar in patients diagnosed with Carrion’s disease and those co-infected with Mycobacterium spp. The most common symptoms were headaches, followed by malaise and arthralgia.

Endocardite infecciosa é uma doença associada à elevada morbidade e letalidade. O diagnóstico precoce e o reconhecimento de sua etiologia podem contribuir para o sucesso do tratamento antibiótico; entretanto, cerca de um quarto das endocardites permanece sem diagnóstico etiológico. Este estudo teve como objetivo principal identificar a frequência de endocardite por Bartonella spp. e Coxiella burnetii dentre as endocardites com culturas negativas comunitárias e avaliar os fatores preditores dessas infecções. Como objetivo secundário compararam-se as características clínicolaboratoriais e prognósticas entre as endocardites comunitárias com culturas negativas e positivas. Foram avaliados também os fatores associados à letalidade intra-hospitalar das endocardites com culturas negativas. Entre janeiro de 2004 e janeiro de 2009, foram investigados 369 episódios consecutivos de endocardite em pacientes atendidos no Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - InCor HC-FMUSP. Foram estudados os casos que ocorreram em adultos, classificados pelos critérios de Duke modificados como \"endocardite definida\" e de origem comunitária. Assim, foram incluídos 221 episódios de endocardite, 170 com culturas positivas e 51 com culturas negativas. Neste último grupo, foram feitas as pesquisas sorológicas (reação de imunofluorescência indireta) e histopatológica de Bartonella spp. e Coxiella burnetii. Consideraram-se positivos títulos de imunoglobulina G (IgG) >= 800 para Bartonella henselae e ou Bartonella quintana, e IgG antifase I para C. burnetii > 800. O estudo histopatológico das valvas cardíacas foi capaz de identificar morfologicamente a etiologia de 87% das endocardites com culturas negativas, enquanto que o método de Gram do tecido a fresco o fez em somente 10% dos casos. As endocardites com culturas negativas apresentaram maior frequência de dispneia à admissão (p=0,001), menor valor de proteína C reativa (p=0,009), menor Fração de Ejeção do Ventrículo Esquerdo (Feve) (p=0,022) e necessitaram de mais tempo para o início do tratamento antibiótico para endocardite (p < 0,001) quando comparadas àquelas com culturas positivas. Não houve diferença estatisticamente significante entre os grupos na letalidade intra-hospitalar e na sobrevida após alta hospitalar. Verificou-se que a presença de diabetes mellitus (p=0,009) ou sepse grave na admissão (p=0,01) esteve independentemente associada ao óbito intra-hospitalar entre as endocardites com culturas negativas. Dez casos de endocardite por Bartonella spp. (frequência 19,6% [IC95%: 9,8 - 33,1]) e quatro casos de endocardite por Coxiella burnetii (frequência 7,8% [IC95%: 2,2 - 18,9]) foram diagnosticados dentre os 51 episódios de endocardite com culturas negativas. As endocardites por Bartonella spp. apresentavam menor Feve (p=0,025), associação com a identificação de cocobacilo Gram-negativo no exame histológico da valva cardíaca (p=0,001) e presença de gato no domicílio (p=0,001). Conclusões: Bartonella spp. e Coxiella burnetii foram as etiologias de quase um terço (27,5%) das endocardites comunitárias com culturas negativas. A presença de gato no domicílio, Feve <= 45%, e a identificação de cocobacilo Gramnegativo no exame histológico da valva cardíaca em pacientes com endocardite com culturas negativas parecem estar associadas à infecção por Bartonella spp. O exame histológico da valva cardíaca permitiu a identificação morfológica do micro-organismo na maioria dos casos, mesmo quando as hemoculturas estavam negativas. Não se observou diferença na letalidade intra-hospitalar e na sobrevida em longo prazo entre os dois grupos. A presença de diabetes mellitus ou sepse grave à admissão associou-se ao óbito hospitalar nas endocardites com culturas negativas / Infective endocarditis is associated with high morbidity and lethality. Early diagnosis and recognition of the specific etiology can contribute to successful antibiotic treatment. However, approximately one-fourth of endocarditis cases remain without an etiologic diagnosis. This study aimed to identify the frequency of endocarditis caused by Bartonella spp. and Coxiella burnetii among cases of community-acquired culture-negative endocarditis and to also assess risk factors for such infections. As a secondary objective, the clinical, laboratory and prognostic features of community-acquired endocarditis were compared. Factors related to the in-hospital lethality of culture-negative endocarditis were also assessed. Between January 2004 and January 2009, 369 consecutive cases of endocarditis were investigated in patients attending the no Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - InCor HC-FMUSP. Cases occurring in adults, those classified by the modified Duke criteria as \"defined endocarditis\" and community-acquired cases were studied. In total, 221 cases of endocarditis comprising 170 culture-positive and 51 culturenegative cases were included. For the culture-negative cases, serology (indirect immunofluorescence reaction) and histopathological analyses for Bartonella spp. and Coxiella burnetii were performed. Cases were considered positive for Bartonella henselae or Bartonella quintana with IgG titers >= 800 and for Coxiella burnetii with antiphase I IgG titers > 800. Histopathological studies of the cardiac valves were capable of morphologically identifying the etiology in 87% of the culture-negative endocarditis cases, whereas the Gram stain was only positive in 10% of cases using fresh tissue. Culture-negative endocarditis patients presented a greater frequency of dyspnea on admission (p=0.001), lower C-reactive protein levels (p=0.009), and a lower left ventricular ejection fraction (LVEF) (p=0.022), and they required more time to start antibiotic therapy (p < 0.001) when compared with culture-positive patients. There was no statistically significant difference between the two groups regarding in-hospital lethality or survival after hospital discharge. Diabetes mellitus (p=0.01) or severe sepsis on admission (p=0.01) were independently associated with in-hospital death for culture-negative endocarditis. Ten cases of endocarditis caused by Bartonella spp. (frequency 19.6% [IC95%: 9.8 - 33.1]) and 4 caused by Coxiella burnetii (frequency 7.8% [IC95%: 2.2 - 18.9]) were diagnosed among the 51 cases of culture-negative endocarditis. Endocarditis caused by Bartonella spp. was associated with lower LVEF values (p=0.025), the identification of Gram-negative coccobacilli in cardiac valve histology (p=0.001) and the presence of a cat in the patient\'s residence (p=0.001). Conclusions: Bartonella spp. and Coxiella burnetii were the causative etiology of almost one-third (27.5%) of the community-acquired cases of culture-negative endocarditis. The presence of a cat in the patient\'s residence, a LVEF <= 45% and the identification of Gram-negative coccobacilli in the histological examination of the cardiac valve in patients with culturenegative endocarditis appear to be associated with Bartonella spp. as the causative etiology. Histological examination of the cardiac valves allowed for morphological identification of the causative microorganism in the majority of cases, even when blood cultures were negative. There was no difference in in-hospital lethality or long-term survival between the two groups. The presence of diabetes mellitus or severe sepsis at admission was associated with in-hospital death in cases of culture-negative endocarditis

Aujourd'hui, l'émergence ou la réémergence de maladies transmises par les tiques (TBDs) devient un problème majeur. En raison des problèmes générés par l'utilisation des acaricides (pollution, résistance), il est donc urgent d'identifier de nouvelles approches pour contrôler les populations de tiques. Parmi ces stratégies, la vaccination visant des molécules conservées chez les tiques et impliquées dans leur capacité vectorielle, sont devenues particulièrement attractives. En conséquence, l'identification de cibles antigéniques appropriées est un défi majeur pour la mise en œuvre de ces stratégies de contrôle des tiques et des TBDs. Dans le présent travail, l'objectif principal est d'élucider les interactions moléculaires entre I. ricinus et B. henselae, afin d'identifier des molécules qui pourraient représenter des cibles vaccinales contre les tiques et les agents pathogènes qu'elles transmettent. Dans ce but, nous avons identifié, par séquençage à haut débit, des transcrits d'Ixodes ricinus différentiellement exprimés au niveau des glandes salivaires de la tique en réponse à une infection par B. henselae. Dans un second temps, l'implication d'un de ces transcrits surexprimés lors de l'infection dans la transmission de B. henselae, a été évaluée. Enfin, et en premier lieu, nous avons validé l'utilisation de la technique de gorgement artificiel sur membrane pour infecter I. ricinus par B. henselae et évalué l'impact de différents paramètres sur le gorgement des tiques. Les résultats ont montré que la technique de gorgement sur membrane est bien adaptée à l'infection d'I. ricinus par B. henselae en laboratoire, et que la proportion et le poids des tiques gorgées sont diminués lors de l'infection du sang par la bactérie Le séquençage en 454 des glandes salivaires de tiques a généré une banque de référence contenant 24, 539 transcrits, et la comparaison des glandes salivaires d'I. ricinus infectés et non-infectés par B. henselae a montré que 839 et 517 transcrits étaient respectivement significativement surexprimés et sous-exprimés en réponse à l'infection par des bactéries. Parmi les gènes de fonction connue, 161 transcrits correspondent à 9 familles déjà identifiées, quand les autres correspondent à des gènes de fonction inconnue. L'extinction par RNA interférence du gène le plus surexprimé, IrSPI qui appartient à la famille des inhibiteurs de sérine protéase BPTI/Kunitz, a entraîné une réduction de la taille du repas sanguin prit par les tiques (et donc sa descendance) ainsi que du niveau d'infection au niveau des glandes salivaires. En conclusion, cette étude a démontré que la technique de gorgement artificiel des tiques sur membrane est un outil puissant pour étudier les interactions entre les tiques et les agents pathogènes qu'elles transmettent comme B. henselae. Ce travail apporte aussi une nette avancée en termes de données génétiques sur I. ricinus (dont le génome n'est pas séquencé) et sur les interactions moléculaires entre une bactérie et son vecteur. Enfin, ce travail a permis la mise en évidence d'une molécule représentant un candidat vaccinal très prometteur à la fois pour diminuer la population de tiques et lutter contre les agents pathogènes qu'elles transmettent. Dans le futur, et en fonction de la confirmation du rôle des gènes identifiés ici dans la transmission bactérienne, de nombreux candidats vaccins pourront ainsi être évalués, ouvrant alors de nouvelles perspectives dans la lutte contre les tiques et les maladies dues aux agents qu'elles transmettent / Ticks are obligate blood-feeding ectoparasites of many hosts including mammals, birds and reptiles. After mosquitoes, they are the most important vectors worldwide, and are able to transmit the highest variety of pathogens including virus, bacteria and parasites. Ixodes ricinus (Acari: Ixodidae), the most common tick species in Europe, is a three-life stage hard tick. It is frequently associated with bites in humans, and transmits several pathogens, including Tick-Borne Encephalitis, Babesia spp., Borrellia spp., Anaplasma spp., and to a lesser extent Bartonella spp. Bartonella spp. are facultative intracellular bacteria associated with a number of emerging diseases in humans and animals. It has been demonstrated that I. ricinus is a competent vector for B. henselae that causes cat scratch disease as well as being increasingly associated with a number of other syndromes, particularly ocular infections and endocarditis. Recently, emergence or re-emergence of tick-borne diseases (TBDs) is increasingly becoming a problem. Indeed, and because of the limited success and disadvantages of controlling TBDs via acaricides, new approaches are urgently needed. Therefore, vaccine strategies that target conserved components of ticks that play roles in vector infestation and vector capacity have become particularly attractive. Accordingly, the identification of suitable antigenic targets is a major challenge for the implementation of tick and TBDs control strategies. In the present work, the main objective is to elucidate molecular interactions between I. ricinus and B. henselae in order to identify some targets that may be used as vaccines against ticks and tick-borne pathogens. Two principal points are focused on: primarily, to identify I. ricinus salivary gland differentially expressed transcripts in response to B. henselae infection with next generation sequencing techniques (454 pyrosequencing and HiSeq 2000); secondly, to validate the implication of one of these transcripts in the transmission of B. henselae. For that purpose, and at first, we validated artificial membrane feeding technique for ticks infection by B. henselae and evaluated the impact of several parameters on tick feeding. Results showed that membrane feeding technique is a suitable method to infect I. ricinus with B. henselae and that the proportion and weight of engorged ticks are decreased by B. henselae infection of the blood meal. Transcriptional analysis of the tick salivary glands generated a reference databank containing 24,539 transcripts, and the comparison of B. henselae-infected and non-infected I. ricinus female salivary glands showed that 839 and 517 transcripts were significantly up- and down-regulated in response to bacteria infection, respectively. Among them, 161 transcripts corresponded to 9 groups of ticks salivary gland gene families already described, when the other ones corresponded to genes of unknown function. Silencing the most up-regulated gene IrSPI, which belongs to BPTI/Kunitz family of serine protease inhibitor, resulted in reduction of tick feeding and bacteria load in tick salivary gland. In conclusion, this work demonstrated that artificial-membrane feeding technique is a powerful tool for investigating the interactions between tick and tick-borne pathogens as B. henselae. It also increases the available genomic information for I. ricinus and the knowledge to improve our understanding of the molecular interaction between tick and tick-borne pathogens. At last, it provides a potential vaccine candidate to control tick-borne diseases. In the future, and depending of differentially expressed genes' role confirmation, more and more vaccine candidate will be provided by this work, and the strategy of controlling tick and tick-borne disease will come to a new stage