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A polyphasic taxonomic study was performed on a group of isolates tentatively identified as Burkholderia cepacia, Ralstonia pickettii or Ralstonia paucula (formerly known as CDC group IVc-2). The isolates were mainly cultured from sputum of cystic fibrosis patients or from soil. SDS-PAGE of whole-cell proteins and AFLP fingerprinting distinguished at least five different species, and this was confirmed by DNA-DNA hybridizations. 16S rDNA sequence analysis of representative strains indicated that these organisms belong to the β-subclass of the Proteobacteria, with the genera INTRODUCTIONThe majority of life-threatening bacterial lung infections in cystic fibrosis (CF) patients are caused by a limited spectrum of bacterial pathogens which include Pseudomonas aeruginosa, Staphylococcus aureus and Burkholderia cepacia (Gilligan, 1991 ;Govan & Deretic, 1996). Other organisms which can be found regularly in respiratory tract specimens of CF patients include Haemophilus influenzae, Stenotro- phomonas maltophilia, certain fungi (e.g. Aspergillus spp.) and viruses (e.g. respiratory syncytial virus) (Gilligan, 1991). In the absence of epidemic spread, B. cepacia only infects a small proportion of CF patients, but it has a major impact on both morbidity and mortality of infected patients and the medical and psychosocial implications of B. cepacia colonization and segregation of colonized and non-colonized patients as a means of infection control are enormous (LiPuma, 1998). Accurate identification of B. cepacia is crucial in patient management and infection control practices, but may be problematic, and misidentification is relatively common (LiPuma, 1998 Vandamme et al., 1999). This report describes the polyphasic taxonomic study which was used for the characterization of these and similar isolates from the environment and human clinical specimens. The genotypic and phenotypic characteristics warranted the classification of the isolates in a novel genus, for which we propose the name Pandoraea. The genus Pandoraea contains five species : Pandoraea apista sp. nov. (the type species), Pandoraea pulmonicola sp. nov., Pandoraea pnomenusa sp. nov., Pandoraea sputorum sp. nov. and Pandoraea norimbergensis (Wittke et al. 1997) comb. nov. (basonym Burkholderia norimbergensis). The name Burkholderia norimbergensis was proposed by Wittke et al. (1997) for a single bacterial isolate capable of hetrotrophic sulfur oxidation, which was isolated from an oxic water layer above a sulfide-containing sediment. METHODSBacterial strains and growth conditions. Strains used in this study are listed in Table 1. All strains were grown aerobically on Trypticase Soy Agar (BBL) at 37 mC unless otherwise indicated.Phenotypic characterization. Classical phenotypic tests were performed as described previously (Vandamme et al., 1993). API ZYM and API20 NE tests were performed according to the recommendations of the manufacturer (bioMe! rieux). Flagella staining was performed using a solution of tannic acid (2 g)\phenol (5 %, w\v)\KAl(SO % ) # (satura...

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The role of several regulatory elements in environmental modulation of mucoidy in Pseudomonas aeruginosa was studied. Transcriptional activation of algD, necessary for the mucoid phenotype, was found to depend on FUS, the newly identified far-upstream sites of the algD promoter. The FUS were delimited to a region spanning nucleotides -432 to -332 relative to the algD mRNA start site. Insertional inactivation of algR in PA0568 abolished the algD promoter response to nitrogen availability and greatly diminished but did not completely eliminate reactivity to changes in salt concentration. Insertional inactivation of rpoN (ntrA) in PA0568 did not affect algR and algD transcription.