Rahnella aquatilis sepsis in an immunocompetent adult. (1/18)

Rahnella aquatilis, a rare enteric gram-negative rod which is infrequently isolated in immunocompromised patients, was isolated as a causative organism of sepsis in a 26-year-old immunocompetent male patient. The contaminated intravenous fluid was confirmed to be the source of the organism.  (+info)

Exposure to airborne microorganisms in Polish sawmills. (2/18)

Microbiological air sampling was performed in four sawmills located in eastern Poland, of which two were processing coniferous wood (pine, fir) and other two deciduous wood (oak, birch). Total concentration of microorganisms (bacteria and fungi) in the air of sawmills processing coniferous wood was on average 20.2 +/- 5.6 x 10(3) cfu/m(3) (mean +/- S.E.) and significantly (p < 0.05) higher compared to those processing deciduous wood where the mean concentration of airborne microorganisms was 9.8 +/- 3.0 x 10(3) cfu/m(3). The greatest concentrations of microorganisms in the sawmills processing coniferous wood were noted at debarking and at first-cut frame sawing of pine logs (42.1 +/- 7.6 x 10(3) cfu/m(3) and 39.8 +/- 7.0 x 10(3) cfu/m(3), respectively). Microflora released into air during debarking consisted mostly of allergenic fungi (mainly Aspergillus fumigatus) and corynebacteria, whereas airborne microflora recovered during first-cut frame sawing constituted mostly of endotoxin-producing Gram- negative bacteria of the genus Rahnella, developing in the sapwood of pine. In the sawmills processing deciduous wood, the largest concentration of microorganisms (30.6 +/- 3.4 x 10(3) cfu/m(3)) was found at sorting of the oak parquet boards and was due to the secondary infection of the boards with moulds Penicillium citrinum during prolonged storing in the open air. Values of the respirable fraction of airborne microflora in the examined sawmills varied within fairly wide limits and were between 22.5 86.6%. Altogether, 34 species or genera of bacteria and 21 species or genera of fungi were identified in the air of sawmills, of which respectively 13 and 9 species or genera were reported as having allergenic and/or immunotoxic properties. The concentrations of airborne bacterial endotoxin which were determined on two sampling sites in the sawmills processing pine and fir, were 0.24 microg/m(3) and 4.00 microg/m(3) respectively, distinctly exceeding the suggested safe level. In conclusion, the workers of Polish sawmills may be exposed on some working stands to airborne microorganisms posing respiratory hazard, of which the greatest risk is represented by allergenic fungi developing on bark of logs or stored wood products and endotoxin-producing Gram-negative bacteria of the genus Rahnella, developing in sapwood of coniferous logs  (+info)

Biochemical-genetic characterization of the chromosomally encoded extended-spectrum class A beta-lactamase from Rahnella aquatilis. (3/18)

From whole-cell DNA of a clinical isolate of the enterobacterial species Rahnella aquatilis, a beta-lactamase gene was cloned that encoded a chromosomally encoded Ambler class A enzyme, RAHN-1. RAHN-1, with a pI of 7.2, shares 76, 73, and 71% amino acid identity with the extended-spectrum beta-lactamase of chromosomal origin from Serratia fonticola and with the plasmid-mediated beta-lactamases CTX-M-2 and CTX-M-1, respectively. The hydrolysis spectrum of the clavulanic acid-inhibited RAHN-1 was expanded to cephalosporins such as cefuroxime, cefotaxime, and ceftriaxone, but not to ceftazidime. Its expression was not inducible.  (+info)

Response of furniture factory workers to work-related airborne allergens. (4/18)

The aim of this work was to determine the reactivity of furniture factory workers to microbial allergens associated with wood dust. Allergological examinations by skin and precipitin tests were performed in 48 workers employed in a factory producing furniture from fibreboards and chipboards, and in 32 healthy urban dwellers not exposed to organic dusts (referents). The skin test was performed by the intradermal method with the saline extracts of the cultures of 3 microbial species (Rahnella sp., Arthrobacter globiformis, Aspergillus fumigatus) associated with wood dust. Skin reactions were recorded after 20 minutes, 8 hours and 24 hours and graded 1-4, depending on the diameter of the reaction. The agar-gel test for the presence of precipitins in serum was performed with the extracts of 15 microbial isolates. The furniture factory workers showed a high skin response to the extracts of environmental microbes. The frequency of early grade 2 reactions (diameter 10 mm) to the extract of Rahnella sp. was 64.6% among furniture workers, being significantly higher (p < 0.001) compared to reference group (18.7%). High frequencies of grade 2 reactions in furniture workers were also found with the extracts of A. globiformis and A. fumigatus (52.1% and 62.5%, respectively). The frequencies of grade 2 delayed (after 8 h) and late (after 24 h) reactions to Rahnella sp. in furniture workers were non-specifically high (97.9%/93.7%) while the response rates to A. globiformis and A. fumigatus were much lower (10.4%/25.0%, and 4.2%/37.5%, respectively). In agar-gel test for detection of precipitins, in most cases very low percentages of positive reactions (0-2.1%) were noted in furniture factory workers. The only exception was a high percentage of positive reactions (27.1%) to the antigen of Pseudomonas maltophilia, which was significantly greater in furniture workers compared to the reference group (p < 0.01). The obtained results suggest that early allergic reactions to microorganisms associated with wood dust are common among workers of furniture industry, which may increase a potential risk of work-related disease in this occupational group.  (+info)

Molecular characterization of the growth phase-dependent expression of the lsrA gene, encoding levansucrase of Rahnella aquatilis. (5/18)

Expression of the lsrA gene from Rahnella aquatilis, encoding levansucrase, is tightly regulated by the growth phase of the host cell; low-level expression was observed in the early phase of cell growth, but expression was significantly stimulated in the late phase. Northern blot analysis revealed that regulation occurred at the level of transcription. The promoter region was identified by primer extension analysis. Two opposite genetic elements that participate in the regulation of lsrA expression were identified upstream of the lsrA gene: the lsrS gene and the lsrR region. The lsrS gene encodes a protein consisting of 70 amino acid residues (M(r), 8,075), which positively activated lsrA expression approximately 20-fold in a growth phase-dependent fashion. The cis-acting lsrR region, which repressed lsrA expression about 10-fold, was further narrowed to two DNA regions by deletion analysis. The concerted action of two opposite regulatory functions resulted in the growth phase-dependent activation of gene expression in Escherichia coli independent of the stationary sigma factor sigma(S).  (+info)

Characterization of five phyllosphere bacteria isolated from Rosa rugosa leaves, and their phenotypic and metabolic properties. (6/18)

Five gram-negative bacteria, all of which were Enterobacteriaceae, were isolated from the phyllosphere of green or senescing leaves of Rosa rugosa, and their phenotypic and physiological characteristics were examined. Partial 16S rDNA sequences led to identification of these isolates as Pantoea agglomerans, Klebsiella terrigena, Erwinia rhapontici, and two strains of Rahnella aquatilis. Interestingly, these phyllosphere bacteria had certain phenotypic and physiological convergences, while they showed their own metabolic properties toward phenolic compounds of plant origin. In particular, the two Ra. aquatilis isolates from the green leaves had a substrate-inducible gallate decarboxylase activity in the resting cells that had been cultured in 1 mM gallic acid- or protocatechuic acid-containing medium. The other three isolates from the senescing leaves did not have this enzyme activity. Simple phenolics that the Ra. aquatilis decarboxylatively produced from benzoic acid derivatives had better antimicrobial activities than those of the substrates.  (+info)

-1 frameshifting at a CGA AAG hexanucleotide site is required for transposition of insertion sequence IS1222. (7/18)

The discovery of programmed -1 frameshifting at the hexanucleotide shift site CGA_AAG, in addition to the classical X_XXY_YYZ heptanucleotide shift sequences, prompted a search for instances among eubacterial insertion sequence elements. IS1222 has a CGA_AAG shift site. A genetic analysis revealed that frameshifting at this site is required for transposition.  (+info)

Rahnella aquatilis bacteremia from a suspected urinary source. (8/18)

A 76-year-old male with prostatic hyperplasia presented with acute pyelonephritis. Blood cultures yielded Rahnella aquatilis. Treatment with intravenous followed by oral levofloxacin resulted in cure. Important characteristics of this organism include its biochemical similarities to Enterobacter agglomerans, its apparent ability to cause bacteremia from a renal focus, and its response to quinolone therapy.  (+info)

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