The genus Rickettsia (Rickettsiales: Rickettsiaceae) includes Gram-negative, small, obligate intracellular, nonmotile, pleomorphic coccobacilli bacteria transmitted by arthropods. Some of them cause human and probably also animal disease (life threatening in some patients). In these guidelines, we give clinical practice advices (microscopy, serology, molecular tools, and culture) for the microbiological study of these microorganisms in clinical samples. Since in our environment rickettsioses are mainly transmitted by ticks, practical information for the identification of these arthropods and for the study of Rickettsia infections in ticks has also been added.

• MeSH
• bakteriologické techniky MeSH
• členovci - vektory mikrobiologie   MeSH
• lidé MeSH
• odběr biologického vzorku MeSH
• Rickettsia izolace a purifikace   MeSH
• rickettsiové infekce diagnóza   mikrobiologie   MeSH
• sérologické testy MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• směrnice pro lékařskou praxi MeSH

Many animals are dependent on microbial partners that provide essential nutrients lacking from their diet. Ticks, whose diet consists exclusively on vertebrate blood, rely on maternally inherited bacterial symbionts to supply B vitamins. While previously studied tick species consistently harbor a single lineage of those nutritional symbionts, we evidence here that the invasive tick Hyalomma marginatum harbors a unique dual-partner nutritional system between an ancestral symbiont, Francisella, and a more recently acquired symbiont, Midichloria. Using metagenomics, we show that Francisella exhibits extensive genome erosion that endangers the nutritional symbiotic interactions. Its genome includes folate and riboflavin biosynthesis pathways but deprived functional biotin biosynthesis on account of massive pseudogenization. Co-symbiosis compensates this deficiency since the Midichloria genome encompasses an intact biotin operon, which was primarily acquired via lateral gene transfer from unrelated intracellular bacteria commonly infecting arthropods. Thus, in H. marginatum, a mosaic of co-evolved symbionts incorporating gene combinations of distant phylogenetic origins emerged to prevent the collapse of an ancestral nutritional symbiosis. Such dual endosymbiosis was never reported in other blood feeders but was recently documented in agricultural pests feeding on plant sap, suggesting that it may be a key mechanism for advanced adaptation of arthropods to specialized diets.

• MeSH
• Francisella genetika   metabolismus   MeSH
• Ixodidae mikrobiologie   fyziologie   MeSH
• přenos genů horizontální MeSH
• Rickettsiales genetika   metabolismus   MeSH
• symbióza fyziologie   MeSH
• vitamin B komplex biosyntéza   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH