RESUMO
In Sweden, human cases of tularemia caused by Francisella tularensis holarctica are assumed to be transmitted by mosquitoes, but how mosquito vectors acquire and transmit the bacterium is not clear. To determine how transmission of this bacterium occurs, mosquito larvae were collected in an area where tularemia is endemic, brought to the laboratory, and reared to adults in their original pond water. Screening of adult mosquitoes by real-time PCR demonstrated F. tularensis lpnA sequences in 14 of the 48 mosquito pools tested; lpnA sequences were demonstrated in 6 of 9 identified mosquito species. Further analysis confirmed the presence of F. tularensis holarctica-specific 30-bp deletion region sequences (FtM19inDel) in water from breeding containers and in 3 mosquito species (Aedes sticticus, Ae. vexans, and Ae. punctor) known to take blood from humans. Our results suggest that the mosquitoes that transmit F. tularensis holarctica during tularemia outbreaks acquire the bacterium already as larvae.
Assuntos
Culicidae/microbiologia , Francisella tularensis/fisiologia , Insetos Vetores/microbiologia , Tularemia/transmissão , Animais , Sequência de Bases , Feminino , Francisella tularensis/genética , Genes Bacterianos/genética , Humanos , Masculino , Dados de Sequência Molecular , Alinhamento de Sequência , Deleção de Sequência/genética , Suécia , Tularemia/microbiologia , Microbiologia da ÁguaRESUMO
The novel genus Holtermanniella is proposed here to accommodate four Cryptococcus species closely related to Holtermannia corniformis that are included in the Holtermannia clade (Basidiomycota, Agaricomycotina). Thus, four novel combinations are proposed: Holtermanniella nyarrowii comb. nov., Holtermanniella festucosa comb. nov., Holtermanniella mycelialis comb. nov. and Holtermanniella wattica comb. nov. In addition, a novel anamorphic yeast species was studied with 15 isolates obtained from different habitats around the world. Analysis of the sequences of the D1/D2 region of their large subunit rDNA showed that the novel species is placed phylogenetically within the Holtermannia clade of the Tremellomycetes (Agaricomycotina, Basidiomycota). PCR fingerprinting and sequencing of ITS1-5.8S-ITS2 showed genetic intraspecific variability among the strains: three groups were formed, which did not correlate with geographical origin or substrate. This novel species, designated the type species of Holtermanniella gen. nov., is described as Holtermanniella takashimae sp. nov.; the type strain is CBS 11174(T) (=HB 982(T) =DBVPG 8012(T)). The order Holtermanniales ord. nov. is proposed here to include Holtermannia (the type genus) and Holtermanniella.
Assuntos
Basidiomycota/classificação , Cryptococcus/classificação , Basidiomycota/genética , Análise por Conglomerados , Cryptococcus/genética , Impressões Digitais de DNA , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Genes de RNAr , Genótipo , Dados de Sequência Molecular , Técnicas de Tipagem Micológica , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo Genético , RNA Fúngico/genética , RNA Ribossômico/genética , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNARESUMO
Two yeast strains isolated in 2007 from fermented pig feed were studied, including the analysis of sequences of the D1/D2 and ITS-regions of the rDNA-repeats, their morphology and nutritional physiology. Sequence comparison of the D1/D2 and ITS regions demonstrated that the strains do not belong to any known species. Therefore, a new species, Cryptococcus cerealis with the type strain CBS 10505, is proposed. The species belongs to Filobasidiales (Agaricomycetes, Basidiomycota), and has Cryptococcus saitoi as the closest related species. The new species is psychrophilic, showing significant growth at 4 and 10 degrees C.
Assuntos
Cryptococcus/classificação , Cryptococcus/isolamento & purificação , Grão Comestível/microbiologia , Microbiologia de Alimentos , Cryptococcus/genética , Cryptococcus/fisiologia , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Fermentação , Dados de Sequência Molecular , Técnicas de Tipagem Micológica , Filogenia , RNA Ribossômico 28S/genética , Análise de Sequência de DNARESUMO
After 27 years with no detected cases, an outbreak of anthrax occurred in a beef cattle herd in the south of Sweden. The outbreak was unusual as it occurred in winter, in animals not exposed to meat-and-bone meal, in a non-endemic country. The affected herd consisted of 90 animals, including calves and young stock. The animals were kept in a barn on deep straw bedding and fed only roughage. Seven animals died during 10 days, with no typical previous clinical signs except fever. The carcasses were reportedly normal in appearance, particularly as regards rigor mortis, bleeding and coagulation of the blood. Subsequently, three more animals died and anthrax was suspected at necropsy and confirmed by culture and PCR on blood samples. The isolated strain was susceptible to tetracycline, ciprofloxacin and ampicillin. Subtyping by MLVA showed the strain to cluster with isolates in the A lineage of Bacillus anthracis. Environmental samples from the holding were all negative except for two soil samples taken from a spot where infected carcasses had been kept until they were picked up for transport. The most likely source of the infection was concluded to be contaminated roughage, although this could not be substantiated by laboratory analysis. The suspected feed was mixed with soil and dust and originated from fields where flooding occurred the previous year, followed by a dry summer with a very low water level in the river allowing for the harvesting on soil usually not exposed. In the early 1900s, animal carcasses are said to have been dumped in this river during anthrax outbreaks and it is most likely that some anthrax spores could remain in the area. The case indicates that untypical cases in non-endemic areas may be missed to a larger extent than previously thought. Field tests allowing a preliminary risk assessment of animal carcasses would be helpful for increased sensitivity of detection and prevention of further exposure to the causative agent.