Chromohalobacter salarius sp. nov., a moderately halophilic bacterium isolated from a solar saltern in Cabo de Gata, Almería, southern Spain

A moderately halophilic, Gram-negative bacterium (strain CG4.1T), which was isolated from a solar saltern at Cabo de Gata, a wildlife reserve located in the province of Almería, southern Spain, was subjected to a polyphasic taxonomic study. This organism was an aerobic, motile rod that produced colonies with a yellow pigment. Strain CG4.1T grew at salinities of 3–25 % (w/v), at 15–45 °C and at pH 5–9. The organism reduced nitrate, hydrolysed starch and had phenylalanine deaminase activity. The major fatty acids were C18 : 1 ω7c, C16 : 0 and C19 : 0 cyclo ω8c. The DNA G+C content was 63.6 mol%. On the basis of phenotypic and phylogenetic data, strain CG4.1T appears to be a member of the genus Chromohalobacter and clustered closely with Chromohalobacter species, with 95–96 % similarity between their 16S rRNA gene sequences. However, DNA–DNA relatedness between the isolate and the type strains of Chromohalobacter species was low. Therefore, it is proposed that strain CG4.1T represents a novel species, Chromohalobacter salarius sp. nov. The type strain is strain CG4.1T (=CECT 5903T=LMG 23626T).

Paenibacillus favisporus sp. nov., a xylanolytic bacterium isolated from cow faeces

During a search for xylan-degrading micro-organisms, a sporulated bacterium was recovered from recent and old cow dung and rectal samples. The isolates were identified as members of a novel species of the genus Paenibacillus, based on 16S rRNA gene sequences. According to the results of phylogenetic analysis, the most closely related species was Paenibacillus azoreducens. Phenotypic and chemotaxonomic analyses and DNA–DNA hybridization experiments also showed that the isolates belonged to a novel species of the genus Paenibacillus. The novel species is a facultatively anaerobic, motile, Gram-variable, sporulated rod. The spores of this rod-shaped micro-organism occur in slightly swollen sporangia and are honeycomb-shaped. The main fatty acid is anteiso-branched C15 : 0. Growth was observed with many carbohydrates, including xylan, as the only carbon source and gas production was not observed from glucose. The novel species produces a wide variety of hydrolytic enzymes, such as xylanases, cellulases, amylases, gelatinase, urease and β-galactosidase. On the contrary, it does not produce caseinase, phenylalanine deaminase or lysine decarboxylase. According to the data obtained in this work, the strains belong to a novel species, for which the name Paenibacillus favisporus sp. nov. is proposed (type strain, GMP01T=LMG 20987T=CECT 5760T).

First Report of a Leaf Blight, Seed Stalk Rot, and Bulb Decay of Onion by Pantoea ananas in Georgia

In May 1997, sweet onions (Allium cepa L.) grown in Toombs County, GA, displayed symptoms of blighted leaves, bleached and rotted seed stalks, and rotted bulbs. Gram-negative bacteria were isolated from infected tissues on nutrient agar and shown to be from the genus Pantoea on the basis of cell morphology (rod-shaped), yellow pigmentation, utilization of glucose in an oxidative and fermentative manner, presence of catalase, and absence of oxidase. These characteristics are typical of bacterial strains belonging to the Enterobacteriaceae (facultative anaerobes). Initially, these bacteria were thought to be P. agglomerans, a common saprophyte associated with plant material. However, fatty acid analysis, using bacterial identification software (MIDI, Dewark, DE), identified (second choice) some strains as possibly being P. ananas.. Further testing indicated that all strains utilized cellobiose, melibiose, inositol, glycerol, and sucrose, but not pectin, starch, or gelatin. However, those strains identified by fatty acid analysis as P. ananas were differentiated from P. agglomerans on the basis of indole production, lack of phenylalanine deaminase, and lack of nitrate reductase. To confirm pathogenicity, three strains of each species (total of six strains) were grown overnight in nutrient broth shake cultures. Bacterial cells were harvested by centrifugation and suspended in 0.01 M phosphate-buffered saline (0.85%). Inoculum was adjusted to approximately 5 × 108 CFU/ml with a spectrophotometer and misted with a chromatography sprayer onto onion leaves of approximately 10-week-old onion plants in the greenhouse. Onions were predisposed by placing them under plastic bags for 18 h prior to inoculation. Inoculated plants were left covered with plastic bags for an additional 24 h after inoculation. There were two plants per pot, each test had three pots, and the test was conducted twice. The three strains of P. agglomerans and buffer control resulted in no symptoms. The three strains of P. ananas produced severe blighting, rapid collapse of tissues, and rapid drying so that leaves were light tan and dry within 3 days. Disease on plants infected with P. ananas continued to develop until death of all foliage and bulbs shriveled and collapsed. Results were consistent for all replications and both trials. Bacteria recovered from diseased tissues were gram-negative, yellow, and facultative anaerobic, and produced indole but not phenylalanine deaminase or nitrate reductase; i.e., the bacteria demonstrated the same characteristics as P. ananas. Although P. agglomerans has been reported to produce similar symptoms in South Africa (1), our P. agglomerans strains were nonpathogenic. To our knowledge this is the first report of P. ananas causing a disease of onion. Reference: (1) M. J. Hattingh and D. F. Walters Plant Dis. 65:615, 1981.

Etude morphologique, physiologique et taxonomique de Bacillus azotoformans

Seventeen strains of the new species Bacillus azotoformans were isolated by enrichment culture in peptone broth inoculated with pasteurized soil and then incubated under N2O at 32 °C. The bacterium is a Gram-negative rod, motile with peritrichous flagella, which produces oval spores without exosporia in swollen sporangia. However, the cells have thick walls, mesosomes, and persistent septa characteristic of Gram-positive bacteria. The bacterium lacks fermentative activity, does not attack carbohydrates, has complex growth requirements, and will grow anaerobically only if one of the following electron acceptors is present: NO3−, NO2−, N2O, S4O6−−, or fumarate. Nitrate, nitrite, and nitrous oxide are denitrified with the production of N2. The microorganism is mesophilic, gives a positive oxidase reaction, synthesizes a type c cytochrome, and does not hydrolyse gelatin, starch, or "Tween 80." Poly-β-hydroxybutyric acid is synthesized when the bacterium is grown in a medium containing DL-3-hydroxybutyrate. The following enzymes are present: nitrate reductase A, respiratory nitrite reductase, tetrathionate and fumarate reductases, and L-glutamate dehydrogenase. The following enzymes are absent: thiosulfate reductase, urease, lecithinase, arginine dihydrolase, phenylalanine deaminase, and catalase. For the 17 strains, the mean value of the G + C percent of the DNA is 39.8 ± 1.2. All the strains are highly similar.

Comparison of thirty-seven strains of Vd-3 bacteria with Agrobacterium radiobacter: morphological and physiological observations

Thirty-seven cultures of Vd-3 bacteria, isolated from clinical specimens, were characterized morphologically and physiologically. The cultures produced positive reactions when tested for oxidase, urease, nitrate reduction, phenylalanine deaminase, oxidative metabolism of carbohydrate substrates, and 3-ketolactose production. These peritrichously flagellated microorganisms were isolated primarily from the respiratory tract. When compared to authentic strains of Agrobacterium, they appeared to be most similar to A. radiobacter. Gas-liquid chromatography of trimethylsilyl derivatives of whole-cell hydrolysates of some of the Vd-3 strains and A. radiobacter yielded nearly identical elution patterns. The Vd-3 cultures were identified as probable strains of A. radiobacter. A method is presented for differentiating cultures of A. radiobacter from other similar bacteria encountered in clinical specimens. Although these bacteria rarely occur in clinical specimens, the clinical microbiologist should be familiar withe their outstanding characteristics.