Preliminary analysis and annotation of the partial genome sequence of Francisella tularensis strain Schu 4.

Francisella tularensis, the aetiological agent of tularemia, is an important pathogen throughout much of the Northern hemisphere. We have carried out sample sequencing of its genome in order to gain a greater insight into this organism about which very little is known, especially at the genetic level. Nucleotide sequence data from a genomic DNA shotgun library of the virulent F. tularensis strain Schu 4 has been partially assembled to provide 1.83 Mb of the genome sequence. A preliminary analysis of the F. tularensis genome sequence has been performed and the data compared with 20 fully sequenced and annotated bacterial genomes. Plasmid-encoded genes, previously isolated from low virulence strains of F. tularensis, were not identified. A total of 1289 potential coding ORFs were identified in the data set., An analysis of this data revealed 413 ORFs which would encode proteins with no homology to known proteins. ORFs which could encode proteins involved in amino acid and purine biosynthesis were also identified. These biosynthetic pathways provide targets for the construction of a defined attenuated mutant of F. tularensis for use as a vaccine against tularemia

Rickettsial spotted fever in capoeirão Village, Itabira, Minas Gerais, Brazil Rickettsiose do grupo da febre maculosa na Vila de Capoeirão, Itabira, Minas Gerais, Brasil

The present study investigated the infection by spotted fever rickettsia in an endemic area for Brazilian spotted fever (BSF; caused by Rickettsia rickettsii) in Minas Gerais State, Brazil. Human, canine and equine sera samples, and Amblyomma cajennense adult ticks collected in a rural area of Itabira City, Minas Gerais State were tested for rickettsial infection. Through Immunofluorescence Assay (IFA) we demonstrated the presence of antibodies anti-R. rickettsii in 8.2%, 81.3% and 100% of the human, canine and equine sera, respectively. None of the 356 tick specimens analyzed were positive for Rickettsia by the hemolymph test or Polymerase Chain Reaction technique (PCR) for the htrA and the gltA genes. Our serological results on horses and dogs (sentinels for BSF) appoint for the circulation of a SFG Rickettsia in the study area, however in a very low infection rate among the A. cajennense tick population.<br>O presente estudo investigou a infecção por rickéttsias do grupo da febre maculosa (GFM) em área endêmica para febre maculosa brasileira (FMB; causada por Rickettsia rickettsii) no Estado de Minas Gerais, Brasil. Amostras de soros de humanos, cães e eqüídeos, e carrapatos Amblyomma cajennense adultos colhidos em um povoado rural em Itabira, Minas Gerais foram testados para infecção por Rickettsia. Pela Reação de Imunofluorescência Indireta (RIFI) foram detectados anticorpos anti-R. rickettsii em 8,2% dos soros humanos, 81,3% dos cães e em 100% dos eqüídeos. Nenhum dos 356 carrapatos se mostrou positivo para Rickettsia no teste de hemolinfa e na reação em cadeia pela polimerase (PCR) objetivando amplificar fragmentos de DNA dos genes htrA and the gltA. Os resultados sorológicos em eqüinos e cães (sentinelas para FMB) apontam para a circulação de uma rickéttsia do GFM na área do estudo, porém, numa freqüência de infecção muito baixa na população do carrapato A. cajennense