Complete degradation of dimethyl phthalate by a Comamonas testosterone strain.

A Comamonas testosterone bacterial strain, named as DB-7, capable of utilizing dimethyl phthalate (DMP) as sole carbon source and energy for growth was isolated from soil with plastic film mulching by an enrichment culture technique. This bacterium was identified as C. testosterone by 16S rRNA sequence analysis and phospholipid fatty acid profile. DB-7 could degrade more than 99% of 450 mg L-1 DMP within 14 hours, and degraded DMP of different concentrations rapidly. The optimal degradation temperature and pH were 30-35 °C and pH 9.0, respectively. The degradation rate of DMP was positively related to inoculum volume of the bacterium. The result of HPLC and LC/MS analysis of metabolic products indicated that the major degrading intermediates were mono-methyl phthalate (MMP) and phthalic acid (PA) during the degradation of DMP by DB-7. Partial sequences of three genes involved in PA metabolism were detected in DB-7, and the expression of phthalate 4, 5-dioxygenase was drastically induced in the presence of DMP and PA. DB-7 is promising to be applied to DMP bioremediation because of its high degrading efficiency.

Identification of Comamonas testosteroni as an androgen degrader in sewage.

Numerous studies have reported the masculinization of freshwater wildlife exposed to androgens in polluted rivers. Microbial degradation is a crucial mechanism for eliminating steroid hormones from contaminated ecosystems. The aerobic degradation of testosterone was observed in various bacterial isolates. However, the ecophysiological relevance of androgen-degrading microorganisms in the environment is unclear. Here, we investigated the biochemical mechanisms and corresponding microorganisms of androgen degradation in aerobic sewage. Sewage samples collected from the Dihua Sewage Treatment Plant (Taipei, Taiwan) were aerobically incubated with testosterone (1 mM). Androgen metabolite analysis revealed that bacteria adopt the 9, 10-seco pathway to degrade testosterone. A metagenomic analysis indicated the apparent enrichment of Comamonas spp. (mainly C. testosteroni) and Pseudomonas spp. in sewage incubated with testosterone. We used the degenerate primers derived from the meta-cleavage dioxygenase gene (tesB) of various proteobacteria to track this essential catabolic gene in the sewage. The amplified sequences showed the highest similarity (87-96%) to tesB of C. testosteroni. Using quantitative PCR, we detected a remarkable increase of the 16S rRNA and catabolic genes of C. testosteroni in the testosterone-treated sewage. Together, our data suggest that C. testosteroni, the model microorganism for aerobic testosterone degradation, plays a role in androgen biodegradation in aerobic sewage.

Biodegradation of propyzamide by Comamonas testosteroni W1 and cloning of the propyzamide hydrolase gene camH.

Propyzamide is a widely used benzamide herbicide for controlling weeds in lettuce, soybeans, cotton and other crops. An efficient propyzamide-degrading strain W1 was firstly isolated from activated sludge and identified as Comamonas testosteroni. A metabolite of propyzamide by strain W1 was firstly identified. The novel gene camH encoding a hydrolase that catalyzed the amide bond cleavage of propyzamide was cloned from strain W1. The gene contained an open reading frame of 1452 bp, the deduced amino acid sequence showed low identity with other amidases. The recombinant enzyme CamH was expressed in Escherichia coli BL21 and purified. CamH displayed the highest activity at 30°C and pH 8.0 with propyzamide as the substrate. These results provide important knowledge on the fate of propyzamide in the biodegradation, and elucidate the biodegradation mechanism of propyzamide by the strain W1.

Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil.

BACKGROUND: Selenium (Se) is an essential trace element in most organisms but has to be carefully handled since there is a thin line between beneficial and toxic concentrations. Many bacteria have the ability to reduce selenite (Se(IV)) and (or) selenate (Se(VI)) to red elemental selenium that is less toxic. RESULTS: A strictly aerobic bacterium, Comamonas testosteroni S44, previously isolated from metal(loid)-contaminated soil in southern China, reduced Se(IV) to red selenium nanoparticles (SeNPs) with sizes ranging from 100 to 200 nm. Both energy dispersive X-ray Spectroscopy (EDX or EDS) and EDS Elemental Mapping showed no element Se and SeNPs were produced inside cells whereas Se(IV) was reduced to red-colored selenium in the cytoplasmic fraction in presence of NADPH. Tungstate inhibited Se(VI) but not Se(IV) reduction, indicating the Se(IV)-reducing determinant does not contain molybdenum as co-factor. Strain S44 was resistant to multiple heavy and transition metal(loid)s such as Se(IV), As(III), Cu(II), and Cd(II) with minimal inhibitory concentrations (MIC) of 100 mM, 20 mM, 4 mM, and 0.5 mM, respectively. Disruption of iscR encoding a transcriptional regulator negatively impacted cellular growth and subsequent resistance to multiple heavy metal(loid)s. CONCLUSIONS: C. testosteroni S44 could be very useful for bioremediation in heavy metal(loid) polluted soils due to the ability to both reduce toxic Se(VI) and Se(IV) to non-toxic Se (0) under aerobic conditions and to tolerate multiple heavy and transition metals. IscR appears to be an activator to regulate genes involved in resistance to heavy or transition metal(loid)s but not for genes responsible for Se(IV) reduction.

Two cases of bacteremia due to an unusual pathogen, Comamonas testosteroni in Iran and a review literature.

Here we describe two cases of bacteremia caused by Comamonas testosteroni in two malignant patients, a 10-year-old boy with brain medulloblastoma and a 19-year-old girl with osteosarcoma admitted in the same hospital at short intervals. This is the first report in Iran on this low inherent virulence organism as a human pathogen.

Genome analysis and characterization of zinc efflux systems of a highly zinc-resistant bacterium, Comamonas testosteroni S44.

A novel and multiple metal(loid)-resistant strain Comamonas testosteroni S44 with a high Zn(2+) resistance level (10 mM) was isolated. To understand the molecular basis for the high zinc resistance, whole genome sequencing was performed and revealed a large number of genes encoding putative metal(loid) resistance proteins, mobile genetic elements (MGEs) and horizontal gene transfer (HGT) events that may have occurred to adapt to a metal(loid)-contaminated environment. In particular, 9 putative Zn(2+) transporters [4 znt operons encoding putative Zn(2+)-translocating P-type ATPases and 5 czc operons encoding putative RND-driven (resistance, nodulation, cell division protein family)] tripartite protein complexes were identified. Real-time RT-PCR analysis revealed that the four zntA-like genes were all induced by Zn(2+), while czcA genes were either Zn(2+)-induced or downregulated by Zn(2+). Furthermore, a zntR1A1 operon encoding a ZntR-type regulator and a P-type ATPase was studied in detail. The zntR1 deletion strain (S44ΔzntR1) displayed intermediate resistance to Zn(2+) (6 mM) and accumulated more intracellular Zn(2+). Reporter gene expression assays indicated that ZntR1 responded to Zn(2+), Cd(2+) and Pb(2+), with Zn(2+) being the best inducer. Gene transcription analysis indicated that ZntR1 was a regulator for transcription of zntA1, while other putative ZntR-type regulators may also regulate the transcription expression of zntA1.

Comamonas testosteroni infection in Taiwan: Reported two cases and literature review.

Comamonas testosteroni is a widely distributed aerobic gram-negative bacillus. Infection by C testosteroni is infrequent, and no such cases have been reported in Taiwan. Here, we would like to present a 54-year-old alcoholic patient from Taiwan, and his left leg was injured during a fishing trip, resulting in left leg cellulitis and C testosteroni bacteremia. The patient's fever subsided after initial treatment with extended-spectrum cephalosporin, whereas his erythematous swelling did not resolve until switched to ciprofloxacin. The second patient is a 73-year-old Taiwanese male with chronic hepatitis B infection, liver cirrhosis, and hepatocellular carcinoma. Comamonas testosteroni bacteremia was found after transarterial embolization. Further studies are necessary to determine the best antibiotic(s) for patients infected with C testosteroni.

Catheter-related bacteremia caused by Comamonas testosteroni in a hemodialysis patient.

Comamonas testosteroni has rarely been implicated as a human pathogen. In general, the outcome of C. testosteroni infections is favorable. We report a case of fatal bacteremia caused by C. testosteroni in a 64-year-old woman on hemodialysis.

[Isolation, identification of methyl tert-butyl ether degradation strain and its degradation kinetics].

A methyl tert-butyl ether degradation strain A1 was isolated from the soil under an old Gingko tree. It was identified preliminarily as Comamonas testosterone by 16S rDNA sequence analysis. The main factors including inoculation amount of microbes, pH, temperature and MTBE concentration that may affect the degradation efficiency of MTBE were further studied. The results indicated that the optimum conditions were as following: pH 7.0, temperature 25 degrees C, inoculation amount of microbes was 2 mL (D600 = 2.523 A), initial MTBE concentration 50 mg/L. Under that condition, MTBE can be reduced by 98.89% with seven days (compared with the blank, the volatilization of MTBE was 46.55%). In addition, the biodegradation process of MTBE can be well described by enzymatic reaction of high concentration inhibition, with the maximum substrate utilization rate 0.872 d(-1), Michaelis-Menten constant 7.832 mg x L(-1), inhibitory constant 130.75 mg x L(-1) respectively.

Post-operative endophthalmitis due to an unusual pathogen, Comamonas testosteroni.

Here, we describe the first report of post-operative endophthalmitis due to Comamonas testosteroni in an elderly diabetic patient after complicated cataract surgery. The isolate was identified by using Mini API strips. The patient was successfully treated with intravitreal ceftazidime and oral ciprofloxacin.

3alpha-Hydroxysteroid dehydrogenase/carbonyl reductase as a tool for isolation and characterization of a new marine steroid degrading bacterial strain.

Steroid contamination of sea water is an ever growing problem and impacts population dynamics of all kinds of sea animals. We have long experience with the soil bacterium Comamonas testosteroni which is able to catabolize a variety of steroids and polycyclic aromatic hydrocarbons, and which might be used in the bioremediation of contaminated soil. For our studies, we use 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase (3 alpha-HSD/CR) as an indicator system, since it is a key enzyme in adaptive steroid degradation in C. testosteroni. In this work, we have isolated a new bacterium (strain H5) from the Baltic Sea at Kiel, Germany, which is able to degrade steroids like testosterone, estradiol, and cholesterol. Strain H5 was characterized as being a gram-negative bacterium that could be best grown in SIN medium supplemented with 1.6-4.1% NaCl. More than 80% of cholesterol was digested when strain H5 was grown in SIN medium containing 0.05 mM cholesterol. ELISA revealed that this salt water strain expresses a 3 alpha-HSD/CR orthologous enzyme. Interestingly, 3 alpha-HSD/CR expression increased after induction with testosterone and estradiol. According to our results, H5 is a new bacterial strain which might be used for the bioremediation of steroid contamination in sea water. Isolation of the 3 alpha-HSD/CR orthologous gene, as well as studies on its regulation are currently in progress. In addition, the exact characterization and systematic classification of this marine steroid degrading bacterial strain is envisaged.

Comamonas testosteroni meningitis in a homeless man.

We report a case of meningitis caused by Comamonas testosteroni in a 54-year-old, alcoholic, homeless man. He, as a pedestrian, was struck by a car and suffered multiple fractures of the facial bones including the left frontal sinus. Over the course of 2-week hospitalization, he was clinically diagnosed with multiple cerebral and cerebellar infarcts resulting in altered mental status. He was pronounced dead 15 days after the injury. At the time of autopsy, diffuse purulent meningitis was found on gross examination. A swab culture of the brain surface was positive for C. Testosteroni, a saprophytic organism commonly found in soil and water. This is the first reported case of fatal meningitis caused by this micro-organism.

Comamonas testosteroni bacteremia in a patient with perforated acute appendicitis. Short communication.

Comamonas testosteroni is an uncommon isolate in the clinical laboratory as a human pathogen. C. testosteroni most commonly emerges in abdominal pathologies especially in perforated appendicitis. In Turkey we report first time a case of bacteremia due to this organism, in a 22-year-old man with perforated acute appendicitis. The organism was shown to be susceptible to routine antibiotics so it was easily eliminated even after having caused a bacteremia.

Design and evaluation of 16S rRNA sequence based oligonucleotide probes for the detection and quantification of Comamonas testosteroni in mixed microbial communities.

BACKGROUND: The beta-proteobacterial species Comamonas testosteroni is capable of biotransformation and also biodegradation of a range of chemical compounds and thus potentially useful in chemical manufacturing and bioremediation. The ability to detect and quantify members of this species in mixed microbial communities thus may be desirable. RESULTS: We have designed an oligonucleotide probe for use in fluorescent in situ hybridization (FISH) and two pairs of PCR primers targeting a C. testosteroni subgroup. The FISH probe and one of the PCR primer pairs are suitable for quantification of C. testosteroni in mixed microbial communities using FISH followed by quantitative image analysis or real-time quantitative PCR, respectively. This has been shown by analysis of samples from an enrichment of activated sludge on testosterone resulting in an increase in abundance and finally isolation of C. testosteroni. Additionally, we have successfully used quantitative PCR to follow the C. testosteroni abundance during a laboratory scale wastewater bioaugmentation experiment. CONCLUSION: The oligonucleotides presented here provide a useful tool to study C. testosteroni population dynamics in mixed microbial communities.

Comamonas (Pseudomonas) testosteroni endocarditis.

Comamonas testosteroni has rarely been implicated as a human pathogen. We report a case of infectious endocarditis due to this organism, occurring in a 49-year-old man. The posterior leaflet of the mitral valve contained a 1 x 1 cm vegetation and showed myxoid degeneration and acute inflammation. The patient had no evidence of reinfection after 32 months. The infection was almost certainly community acquired, as is usually true for this organism.