Comamonas suwonensis sp. nov., isolated from stream water in the Republic of Korea.

A novel bacterial strain, EJ-4T, isolated from stream water collected at Seo-ho in Suwon, Republic of Korea, was characterized based on a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain EJ-4T belonged to the genus Comamonas. The isolate is Gram-stain-negative, non-motile, aerobic, rod-shaped and forms pale yellow colonies on trypticase soy agar. The optimal growth of this strain was observed aerobically at 30 °C, pH 7 and 0.5 % NaCl. The major fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c; 39.7 %) and C16 : 0 (32.0 %). The G+C content of strain EJ-4T was 58.4mol %. The average nucleotide identity and digital DNA-DNA hybridization values between strain EJ-4T and Comamoas testosteroni were 91.8 and 31.2 %, respectively. The major polar lipids detected in the isolate were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The predominant isoprenoid quinone was ubiquinone-8. Based on the results of polyphasic taxonomic analysis of strain EJ-4T, we describe a novel species of the genus Comamonas, for which the name Comamonas suwonensis sp. nov. has been proposed, with EJ-4T (=KCTC 82074T=JCM 34179T=KEMB 1602-279T) as the type strain.

First report of urinary tract infection caused by Comamonas kerstersii in a goat.

BACKGROUND: Comamonas kerstersii is rarely associated with infections in humans and has never been reported in animals until now. CASE PRESENTATION: Herein, we describe a case of urinary tract infection caused by C. kerstersii in a young goat. A seven-month-old male goat showed lethargy, generalised weakness and anorexia and in the last hours before its death, severe depression, slight abdominal distention, ruminal stasis, and sternal recumbency. Grossly, multifocal haemorrhages in different organs and tissues, subcutaneous oedema and hydrocele, serous fluid with scattered fibrin deposition on the serosa of the abdominal organs and severe pyelonephritis with multifocal renal infarction were detected. Histopathological examination confirmed severe chronic active pyelonephritis with renal infarcts, multi-organ vasculitis and thrombosis suggestive of an infectious diseases of bacterial origin. The bacterium was identified using routine methods, matrix assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS), and sequencing of the gyrB gene. CONCLUSIONS: To the best of our knowledge, this is the first report of C. kerstersii infection in animals (goat). Our findings support the possibility of C. kerstersii isolation from extraintestinal sites and suggest this organism as a possible cause of urinary tract infection.

Comamonas flocculans sp. nov., a Floc-Forming Bacterium Isolated from Livestock Wastewater.

A Gram-negative, aerobic, non-motile, rod-shaped, floc-forming, and non-spore-forming bacterium, designated as NLF-7-7T, was isolated from the biofilm of a sample collected from a livestock wastewater treatment plant in Nonsan, Republic of Korea. Strain NLF-7-7T, forms a visible floc and grows in the flocculated state. Cells of strain NLF-7-7T grew optimally at pH 6.5 and 30 °C and in the presence of 0.5% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain NLF-7-7T belonged to the family Comamonadaceae, and was most closely related to Comamonas badia DSM 17552T (95.8% similarity) and Comamonas nitrativorans 23310T (94.0% similarity). The phylogenetic and phenotypic data indicate strain NLF-7-7T is clearly distinguished from the Comamonas lineage. The major cellular fatty acids were C10:0 3OH, C16:0, and summed feature 3 (C16:1 ω6c/C16:1 ω7c). The respiratory quinone was Q-8. The polar lipids were composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified aminolipid. The DNA G+C content of strain NLF-7-7 was 68.0 mol%. Based on the phenotypic, chemotaxonomic, and phylogenetic properties, strain NLF-7-7T represents a novel species of the genus Comamonas, for which the name Comamonas flocculans sp. nov. is proposed. The type strain is C. flocculans NLF-7-7T (=KCTC 62943T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of Comamonas flocculans NLF-7-7T is MN527436. The whole-genome shotgun BioProject Number is PRJNA555370 with the Accession Number CP042344.

Comamonas aquatilis sp. nov., isolated from a garden pond.

A beige-pigmented bacterial strain, SB30-Chr27-3T, isolated from a garden pond, was studied for its taxonomic position. Cells of the isolate were rod-shaped and stained Gram-negative. A comparison of the 16S rRNA gene sequence with the sequences of the type strains of the most closely related species showed that the strain belongs to the genus Comamonas and showed highest sequence similarities to the type strains of Comamonas jiangduensis (97.5 %), Comamonas aquatica (97.4 %) and Comamonas phosphati (97.3 %). The 16S rRNA gene sequence similarities to all other Comamonas species were below 97.0 %. The fatty acid profile of strain SB30-Chr27-3T consisted of the major fatty acids C16 : 0, C15 : 0iso 2-OH/ C16 : 1ω7c, C18 : 1ω7c/C18 : 1ω9c and, in a minor amount, C10 : 0 3-OH. Major compounds in the polar lipid profile were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine and diphosphatidylglycerol. The quinone system was exclusively composed of ubiquinone Q-8. The polyamine pattern contained the major compounds putrescine, cadaverine and 2-hydroxyputrescine. These data and the differentiating biochemical properties indicated that isolate SB30-CHR27-3T represents a novel species of the genus Comamonas, for which we propose the name >Comamonas aquatilis sp. nov. with the type strain SB30-Chr27-3T (=CIP 111491T=CCM 8815T).

Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria.

The surfactant sodium lauryl ether sulfate (SLES) is widely used in the composition of detergents and frequently ends up in wastewater treatment plants (WWTPs). While aerobic SLES degradation is well studied, little is known about the fate of this compound in anoxic environments, such as denitrification tanks of WWTPs, nor about the bacteria involved in the anoxic biodegradation. Here, we used SLES as sole carbon and energy source, at concentrations ranging from 50 to 1000 mg L-1, to enrich and isolate nitrate-reducing bacteria from activated sludge of a WWTP with the anaerobic-anoxic-oxic (A2/O) concept. In the 50 mg L-1 enrichment, Comamonas (50%), Pseudomonas (24%), and Alicycliphilus (12%) were present at higher relative abundance, while Pseudomonas (53%) became dominant in the 1000 mg L-1 enrichment. Aeromonas hydrophila strain S7, Pseudomonas stutzeri strain S8, and Pseudomonas nitroreducens strain S11 were isolated from the enriched cultures. Under denitrifying conditions, strains S8 and S11 degraded 500 mg L-1 SLES in less than 1 day, while strain S7 required more than 6 days. Strains S8 and S11 also showed a remarkable resistance to SLES, being able to grow and reduce nitrate with SLES concentrations up to 40 g L-1. Strain S11 turned out to be the best anoxic SLES degrader, degrading up to 41% of 500 mg L-1. The comparison between SLES anoxic and oxic degradation by strain S11 revealed differences in SLES cleavage, degradation, and sulfate accumulation; both ester and ether cleavage were probably employed in SLES anoxic degradation by strain S11.

Isolation and characterization of polycyclic aromatic hydrocarbon-degrading bacteria with tolerance to hypoxic environments.

Hypoxic conditions are considerably different from aerobic and anaerobic conditions, and they are widely distributed in natural environments. Many pollutants, including polycyclic aromatic hydrocarbons (PAHs), tend to accumulate in hypoxic environments. However, PAH biodegradation under hypoxic conditions is poorly understood compared with that under obligate aerobic and obligate anaerobic conditions. In the present study, PAH-degrading bacteria were enriched, and their biodegradation rates were tested using a hypoxic station with an 8% oxygen concentration. PAH-degrading bacteria collected from sediments in low-oxygen environments were enriched using phenanthrene (Phe) or pyrene (Pyr) as the sole carbon and energy source. Individual bacterial colonies showing the ability to degrade Phe or Pyr were isolated and identified by 16S rDNA gene sequencing. Morphological and physiological characterizations of the isolated bacterial colonies were performed. The isolated bacteria were observed by scanning electron microscopy (SEM) and were identified as Pseudomonas sp., Klebsiella sp., Bacillus sp., and Comamonas sp. Phylogenetic tree of the isolated PAH-degrading bacteria was also constructed. The biodegradation ability of these bacteria was tested at an initial Phe or Pyr concentration of 50 mg L-1. The biodegradation kinetics were best fit by a first-order rate model and presented regression coefficients (r2) that varied from 0.7728 to 0.9725 (P < 0.05). The half-lives of the PAHs varied from 2.99 to 3.65 d for Phe and increased to 60.3-82.5 d for Pyr. These half-lives were much shorter than those observed under anaerobic conditions but were similar to those observed under aerobic conditions.

Comamonas phosphati sp. nov., isolated from a phosphate mine.

A Gram-stain-negative, facultatively anaerobic, non-pigmented, non-sporulating, rod-shaped bacterial strain (WYH 22-41T) was isolated from a phosphate mine in Yunnan Province, China. The cells were motile with a single polar flagellum. The 16S rRNA gene of strain WYH 22-41T was phylogenetically related to the corresponding gene of Comamonas terrae DSM 27221T (98.4 % 16S rRNA gene sequence similarity), Comamonas odontotermitis LMG 23579T (97.6 %) and Comamonas aquatica LMG 2370T (97.4 %). DNA-DNA hybridizations of strain WYH 22-41T with these three strains showed relatedness values of 33.2 %, 20.5 % and 27.7 %, respectively. The DNA G+C content of strain WYH 22-41T was 62.4 mol%. The predominant respiratory quinone was ubiquinone-8. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The major fatty acids of strain WYH 22-41T were C16 : 0, C17 : 0 cyclo, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). On the basis of phenotypic properties, phylogenetic characteristics, DNA-DNA hybridization, as well as whole-cell fatty acid composition, strain WYH 22-41T represents a novel species of the genus Comamonas, for which the name Comamonas phosphati sp. nov. is proposed. The type strain is WYH 22-41T ( = CGMCC 1.12294T = DSM 26017T).

Description of Comamonas sediminis sp. nov., isolated from lagoon sediments.

Strain S3T was isolated from lagoon sediments, and appeared as transparent colonies on agar plates, with cells staining Gram-negative. Catalase and oxidase were positive. S3T hydrolyzed starch, casein and tween-20, while urea, chitin, gelatin and tween-80 were not hydrolysed. C18 : 1ω6c/C18 : 1ω7c, C16 : 1ω6c/C16 : 1ω7c,C17 : 0 cyclo and C16 : 0 were the predominant fatty acids with minor amounts of C10 : 0 3-OH, C12 : 0, C14 : 0 and C16 : 0 2-OH. S3T contained diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), and phosphatidylethanolamine (PE) as major polar lipids with minor amounts of unidentified phospholipid (PL) and unidentified lipids (L1-2). Genomic DNA G+C content was 68.3 mol%. 16S rRNA gene sequence comparisons indicated that S3T represents a member of the genus Comamonas in family Comamonadaceae of the class Betaproteobacteria. S3T has a sequence similarity of 98.96 % with Comamonas koreensis YH12T, 97.93 % with Comamonas guangdongensis CY01T and <96.97 % with other members of the genus Comamonas. DNA-DNA hybridization values between S3T and the type strains of the most closely related species were clearly below the 70 % threshold. On the basis of phenotypic, genotypic and phylogenetic analysis, it is proposed that S3T represents a novel species of the genus Comamonas, for which the name Comamonas sediminis sp. nov. is proposed. The type strain is S3T (=KEMB 563-466T =JCM 31169T).

Bacteremia caused by Comamonas kerstersii in a patient with diverticulosis.

We report for the first time a case of bacteremia caused by Comamonas kerstersii in a 65-year-old patient with sign of diverticulosis. In addition, we review the isolation of Comamonas sp. and related organisms in our hospital over 25 years.

Comamonas humi sp. nov., isolated from soil.

A bacterial strain, designated GAU11(T), was isolated from soil in Japan. Cells of the strain were Gram-stain-negative, aerobic, non-motile rods. The 16S rRNA gene sequence of strain GAU11(T) showed high similarity to those of Comamonas zonglianii BF-3(T) (98.8 %), Pseudacidovorax intermedius CC21(T) (96.4 %), Acidovorax caeni R-24608(T) (96.2 %), Alicycliphilus denitrificans K601(T) (96.2 %), Pseudorhodoferax soli TBEA3(T) (95.9 %) and Comamonas terrigena LMG 1253(T) (95.9 %). Strain GAU11(T) contained ubiquinone 8 as the sole ubiquinone and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol as major polar lipids. Its major cellular fatty acids were C16 : 0, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The DNA G+C content of strain GAU11(T) was 68.2 mol%. The DNA-DNA relatedness between strain GAU11(T) and C. zonglianii DSM 22523(T) was 52 or 68 % (reciprocal value). Phenotypic characterization indicated that strain GAU11(T) represents a member of the genus Comamonas, but at the same time distinguished it from C. zonglianii DSM 22523(T). From polyphasic characterization, this strain should be classified as representing a novel species of the genus Comamonas, for which the name Comamonas humi sp. nov. (type strain GAU11(T) = JCM 19903(T) = DSM 28451(T)) is proposed.

Description of Comamonas serinivorans sp. nov., isolated from wheat straw compost.

A Gram-stain-negative bacterium, designated SP-35(T), was isolated from compost and was subjected to a taxonomic study. This isolate was short-rod-shaped and non-spore-forming. Phylogenetic analysis based on 16S rRNA sequence comparison indicated the isolate was related to the genus Comamonas. 16S rRNA gene sequence analysis showed that its closest neighbours were the type strains Comamonas odontotermitis Dant 3-8(T) (96.8 % similarity), Comamonas testosteroni DSM 50244(T) (96.5 %), Comamonas guangdongensis CY01(T) (95.9 %) and Comamonas composti YY287(T) (95.6 %). Using phylogenetic analysis, DNA-DNA hybridization, fatty acid composition data and a range of physiological and biochemical characteristics we could clearly distinguish strain SP-35(T) from type strains of the genus Comamonas. The genomic DNA G+C content of strain SP-35(T) was 63.1 mol%. The predominant cellular fatty acids were C16 : 0, C17 : 0 cyclo, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidlyglycerol. Differences in phenotypic and phylogenetic characteristics support the classification of strain SP-35(T) as a representative of a novel species in the genus Comamonas, for which the name Comamonas serinivorans sp. nov. is proposed. The type strain is SP-35(T) ( = DSM 26136(T) = JCM 18194(T)).

Comamonas faecalis sp. nov., isolated from domestic pig feces.

A new bacterial strain, designated as FF42(T), was isolated from feces of domestic pigs-collected from Suwon, Korea-and was characterized to determine its taxonomic position. Strain FF42(T) was observed to be Gram negative, aerobic, non-spore forming, motile, and rod-shaped cells. Based on the phylogenetic and 16S rRNA sequence analyses, it was revealed that strain FF42(T) belonged to the genus Comamonas. The highest degree of sequence similarities was determined to be with Comamonas zonglianii BF-3(T) (96.3 %), Comamonas composti CC-YY287(T) (96.1 %), and Comamonas nitrativorans 23310(T) (95.9 %), while showing less than 95.6 % identity with the remaining Comamonas species. Growth of strain FF42(T) occurred between 25 and 40 °C (optimum, 28 °C) and at pH of 5-9 (optimum, pH 6.0). It grew in the presence of 0-3 % (w/v) NaCl while minimally tolerating at 3 % (w/v) NaCl. Biochemical and physiological tests revealed phenotypic differentiation of strain FF42(T) to other members of the genus Comamonas. The predominant quinone is ubiquinone (Q-8). The major cellular fatty acids were C10:0 3OH, C16:0, summed feature 3 (C16:1 ω7c/C16:1 ω6c), and summed feature 8 (C18:1 ω6c/C18:1 ω7c), all of which have previously been reported to occur in the species of the genus Comamonas. The G+C molar content for strain FF42(T) is 60.2 mol %. Based on phylogenetic and phenotypic analyses, strain FF42(T) (=KEMC 1002-058(T)=JCM 17561(T)) is clearly referred to be a novel species for the genus Comamonas, for which the name Comamonas faecalis sp. nov. is proposed.

Intra-abdominal infections due to Comamonas kerstersii.

Herein, we report four cases of Comamonas kerstersii intra-abdominal infections representing the first report of human infections caused by this Comamonas species. In addition, our work demonstrates the association of C. kerstersii with peritonitis secondary to appendix rupture.

Comamonas jiangduensis sp. nov., a biosurfactant-producing bacterium isolated from agricultural soil.

A novel biosurfactant-producing strain, designated YW1(T), was isolated from agricultural soil. Its taxonomic position was investigated using a polyphasic approach. The cells were short rods, Gram-negative, non-sporulating and motile. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YW1(T) was a member of the genus Comamonas, and showed highest sequence similarities to Comamonas aquatica LMG 2370(T) (98.5%), Comamonas kerstersii LMG 3475(T) (97.7%) and Comamonas terrigena LMG 1253(T) (97.7%). Furthermore, DNA-DNA hybridization experiments against these three strains gave results that were clearly lower than 70% DNA-DNA similarity, and consequently confirmed that this new strain does not belong to a previously described species of the genus Comamonas. The major respiratory quinone was ubiquinone-8. The major fatty acids (>5%) were C16:0 (30.1%), summed feature 3 (C16:1ω6c and/or C16:1ω7c; 25.4%), summed feature 8 (C18:1ω6c and/or C18:1ω7c; 15.3%), C17:0 cyclo (7.4%) and C14:0 (5.8%). The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unknown phospholipids and unknown lipids. Based on the phylogenetic analysis, DNA-DNA hybridization, whole-cell fatty acid composition as well as biochemical characteristics, strain YW1(T) was clearly distinguishable from all species of the genus Comamonas with validly published names and should be classified as a representative of a novel species of the genus Comamonas, for which the name Comamonas jiangduensis sp. nov. is proposed. The type strain is YW1(T) (=CCTCC AB 2012033(T)=KACC 16697(T)).

Comamonas guangdongensis sp. nov., isolated from subterranean forest sediment, and emended description of the genus Comamonas.

A facultatively anaerobic bacterium, strain CY01(T), isolated from subterranean forest sediment collected from Guangdong Province, China, was investigated using a polyphasic taxonomic approach. The cells were short rods, Gram-negative, non-sporulating and motile. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CY01(T) showed highest sequence similarities to Comamonas thiooxydans S23(T) (98.0 %), Comamonas testosteroni JCM 5832(T) (97.9 %), Comamonas koreensis KCTC 12005(T) (97.7 %) and Comamonas odontotermitis LMG 23579(T) (97.0 %). The major respiratory quinone was ubiquinone-8. The major cellular fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C16 : 0 and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). Based on the phylogenetic analysis, DNA-DNA hybridization, whole-cell fatty acid composition as well as biochemical characteristics, strain CY01(T) was clearly distinguishable from all recognized species of the genus Comamonas and should be classified as a representative of a novel species of the genus, for which the name Comamonas guangdongensis sp. nov. is proposed. The type strain is CY01(T) ( = CCTCC AB 2011133(T) = KACC 16241(T)).

IncP-1ß plasmids of Comamonas sp. and Delftia sp. strains isolated from a wastewater treatment plant mediate resistance to and decolorization of the triphenylmethane dye crystal violet.

The application of toxic triphenylmethane dyes such as crystal violet (CV) in various industrial processes leads to large amounts of dye-contaminated sludges that need to be detoxified. Specific bacteria residing in wastewater treatment plants (WWTPs) are able to degrade triphenylmethane dyes. The objective of this work was to gain insights into the genetic background of bacterial strains capable of CV degradation. Three bacterial strains isolated from a municipal WWTP harboured IncP-1ß plasmids mediating resistance to and decolorization of CV. These isolates were assigned to the genera Comamonas and Delftia. The CV-resistance plasmid pKV29 from Delftia sp. KV29 was completely sequenced. In addition, nucleotide sequences of the accessory regions involved in conferring CV resistance were determined for plasmids pKV11 and pKV36 from the other two isolates. Plasmid pKV29 contains typical IncP-1ß backbone modules that are highly similar to those of previously sequenced IncP-1ß plasmids that confer antibiotic resistance, degradative capabilities or mercury resistance. The accessory regions located between the conjugative transfer (tra) and mating pair formation modules (trb) of all three plasmids analysed share common modules and include a triphenylmethane reductase gene, tmr, that is responsible for decolorization of CV. Moreover, these accessory regions encode other enzymes that are dispensable for CV degradation and hence are involved in so-far-unknown metabolic pathways. Analysis of plasmid-mediated degradation of CV in Escherichia coli by ultra-high-performance liquid chromatography-electrospray ionization-quadrupole-time-of-flight MS revealed that leuco crystal violet was the first degradation product. Michler's ketone and 4-dimethylaminobenzaldehyde appeared as secondary degradation metabolites. Enzymes encoded in the E. coli chromosome seem to be responsible for cleavage of leuco crystal violet. Plasmid-mediated degradation of triphenylmethane dyes such as CV is an option for the biotechnological treatment of sludges contaminated with these dyes.

Isolation of bacteria capable of growth with 2-methylisoborneol and geosmin as the sole carbon and energy sources.

Using a relatively simple enrichment technique, geosmin and 2-methylisoborneol (MIB)-biodegrading bacteria were isolated from a digestion basin in an aquaculture unit. Comparison of 16S rRNA gene sequences affiliated one of the three isolates with the Gram-positive genus Rhodococcus, while the other two isolates were found to be closely related to the Gram-negative family Comamonadaceae (Variovorax and Comamonas). Growth rates and geosmin and MIB removal rates by the isolates were determined under aerated and nonaerated conditions in mineral medium containing either of the two compounds as the sole carbon and energy source. All isolates exhibited their fastest growth under aerobic conditions, with generation times ranging from 3.1 to 5.7 h, compared to generation times of up to 19.1 h in the nonaerated flasks. Incubation of the isolates with additional carbon sources caused a significant increase in their growth rates, while removal rates of geosmin and MIB were significantly lower than those for incubation with only geosmin or MIB. By fluorescence in situ hybridization, members of the genera Rhodococcus and Comamonas were detected in geosmin- and MIB-enriched sludge from the digestion basin.

A novel bacterial symbiont in the nematode Spirocerca lupi.

BACKGROUND: The parasitic nematode Spirocerca lupi (Spirurida: Thelaziidae), the canine esophageal worm, is the causative agent of spirocercosis, a disease causing morbidity and mortality in dogs. Spirocerca lupi has a complex life cycle, involving an obligatory coleopteran intermediate host (vector), an optional paratenic host, and a definitive canid host. The diagnosis of spirocercosis is challenging, especially in the early disease stages, when adult worms and clinical signs are absent. Thus, alternative approaches are needed to promote early diagnosis. The interaction between nematodes and their bacterial symbionts has recently become a focus of novel treatment regimens for other helminthic diseases. RESULTS: Using 16S rDNA-based molecular methods, here we found a novel bacterial symbiont in S. lupi that is closely related to Comamonas species (Brukholderiales: Comamonadaceae) of the beta-proteobacteria. Its DNA was detected in eggs, larvae and adult stages of S. lupi. Using fluorescent in situ hybridization technique, we localized Comamonas sp. to the gut epithelial cells of the nematode larvae. Specific PCR enabled the detection of this symbiont's DNA in blood obtained from dogs diagnosed with spirocercosis. CONCLUSIONS: The discovery of a new Comamonas sp. in S. lupi increase the complexity of the interactions among the organisms involved in this system, and may open innovative approaches for diagnosis and control of spirocercosis in dogs.

The effect of some factors of polluted environment on catalase responses and resistance of microbial isolates against toxic oxidative stress.

The properties of bacterial isolates from polluted environments which are characterized by increased levels of oxidative stress do not reflect only the level of contaminants, but also arise as a consequence of many permanently changed conditions. The survival rate of Comamonas terrigena N3H isolates from an environment with elevated levels of H(2)O(2) is correlated with stimulation of catalase. The response of bacterial catalase to the effect of phenol in exogenous conditions was affected by the presence of an additional contaminant, Cd(2+). An isolate of Aspergillus niger selected from river sediment containing 363 mg/kg As, 93 mg/kg Sb at pH 5.2-4.8 grew on Czapek-Dox agar ~1.6 times faster than an isolate of the same species from coal dust sediment with approximately the same level of pollution (400 mg/kg As) but somewhat lower pH (3.3-2.8). It also exhibited differences in the microscopic characteristics of its mycelial structures. Both isolates exhibited a higher tolerance to the exogenic toxic effects of metals (As(5+), Cd(2+), and Cu(2+) at 5, 25, or 50 mg/L) than a control culture, but the differences in tolerance between them were only slight. These laboratory results suggest that there are complicated relationships which may exist in the "in situ" environment.

Indigo biosynthesis by Comamonas sp. MQ.

An indigo-producing strain was isolated from activated sludge and identified as Comamonas sp. based on 16S rRNA analysis. It produced indigo at 26.5 mg/l with a conversion of indole to indigo of 47%. Indole at 50 mg/l plus 200 mg naphthalene/l gave 32.2 mg indigo/l with a 58% conversion. A pathway for indigo formation is proposed. This is the first study of indigo biosynthesis by Comamonas sp.