ABSTRACT
To investigate the degradation of polycyclic aromatic hydrocarbons (PAHs) and the changes of rhizosphere microorganisms in the rhizosphere soil of Leymus chinensis during the remediation of PAHs contaminated soil by Comamonas testosteroni (C.t)-assisted Leymus chinensis, we evaluated the removal of PAHs in the rhizosphere of Leymus chinensis using gas chromatography-mass spectrometry (GC-MS), analyzed the bacterial community and the diversity in Leymus chinensis rhizosphere soil by high-throughput sequencing technology, characterized the correlation among PAHs degradation and bacterial community components performing redundancy analysis (RDA) and network analysis, and predicted PAHs degradation potential via PICRUSt software in this paper. The degradation of PAHs in the rhizosphere of Leymus chinensis was promoted, the abundance and diversity of bacteria and the correlation among bacteria and PAHs were changed, and the degradation potential of PAHs in Leymus chinensis rhizosphere soil was enhanced in the later stage of phytoremediation (60-120 d) due to the incorporation of C.t. The accelerated degradation of three PAHs (Nap, Phe, BaP) was accompanied by the differ abundance and correlation of Proteobacteria (Sphingomonas, MND1, Nordella), Actinomycetes (Rubrobacter, Gaiella), Acidobacteria (RB41) and Bacteroides (Flavobacterium) affected by C.t. The results provide new insight into the microorganism choices for microbial assisted plant remediation of soil PAHs and the mechanisms of enhanced PAHs degradation via the combination of Comamonas testosteroni engineering bacteria and plants.
Subject(s)
Biodegradation, Environmental , Comamonas testosteroni/genetics , Polycyclic Aromatic Hydrocarbons/analysis , Rhizosphere , Soil , Soil Microbiology , Soil PollutantsABSTRACT
OBJECTIVE@#To determine the drug resistance of Comamonas testosteroni (C. testosteroni) by the Kirby-Bauer (K-B) method without Clinical and Laboratory Standards Institute (CLSI) explanation or the minimum inhibitory concentration (MIC) method with the standard CLSI explanation to evaluate the sensitivity of K-B method in detection of C. testosteroni. @*METHODS@#K-B method and MIC method was used to determine the sensitivity of C. testosteroni to Piperacillin, Cefepime, Piperacillin/tazobactam, Imipenem, Meropenem, Amikacin, Gentamicin, Tobramycin, Ceftazidime and Ciprofloxacin. The interpretation standard for Pseudomonas aeruginosa was temporary used for the K-B method. The coincident rate was compared between the two methods. @*RESULTS@#The complete or partial coincident rate for K-B method and MIC method to detect Piperacillin and Cefepime was 97.4% or 2.6%; the complete coincidence rate to detect Piperacillin/tazobactam, Imipenem and Meropenem was 100%; the complete or partial coincident rate to detect Amikacin, Gentamicin and Tobramycin 94.7% or 5.3%; the complete or partial coincident rate to detect Ceftazidime was 97.4% or 2.6%; the complete or partial coincident rate to detect Ciprofloxacin 86.8% or 10.6%, and the full non-coincidence rate was 2.6%. @*CONCLUSION@#The results of drug sensitive test from the two methods are highly consistent. We suggest that the microbiology labs do not report the interpretive results for C. testosteroni with K-B method but report the test results.
Subject(s)
Anti-Bacterial Agents , Cefepime , Cephalosporins , Comamonas testosteroni , Imipenem , Meropenem , Microbial Sensitivity Tests , Penicillanic Acid , Piperacillin , Piperacillin, Tazobactam Drug Combination , Pseudomonas aeruginosa , ThienamycinsABSTRACT
Comamonas testosteroni and Acinetobacter guillouiae are gram-negative bacilli of low virulence that are widely distributed in nature and normal flora. Despite their common occurrence in environments, they rarely cause infectious disease. We experienced a case of septic shock by C. testosterone and A. guillouiae, and isolated them by 16S ribosomal RNA sequencing method from the blood cultures of a previous healthy female during postoperative supportive care. This is the first case of septic shock required ventilator care and continuous renal replacement therapy due to these organisms in Korea.
Subject(s)
Female , Humans , Acinetobacter , Bacteremia , Comamonas testosteroni , Comamonas , Communicable Diseases , Korea , Renal Replacement Therapy , RNA, Ribosomal, 16S , Shock, Septic , Testosterone , Ventilators, Mechanical , VirulenceABSTRACT
Comamonas testosteroni and Acinetobacter guillouiae are gram-negative bacilli of low virulence that are widely distributed in nature and normal flora. Despite their common occurrence in environments, they rarely cause infectious disease. We experienced a case of septic shock by C. testosterone and A. guillouiae, and isolated them by 16S ribosomal RNA sequencing method from the blood cultures of a previous healthy female during postoperative supportive care. This is the first case of septic shock required ventilator care and continuous renal replacement therapy due to these organisms in Korea.
Subject(s)
Female , Humans , Acinetobacter , Bacteremia , Comamonas testosteroni , Comamonas , Communicable Diseases , Korea , Renal Replacement Therapy , RNA, Ribosomal, 16S , Shock, Septic , Testosterone , Ventilators, Mechanical , VirulenceABSTRACT
Comamonas testosteroni has rarely been implicated as a human pathogen. We here present a case of peritonitis due to this organism in a patient on continuous ambulatory peritoneal dialysis (CAPD). A 32-year-old woman was admitted with abdominal pain and cloudy peritoneal effluent. Empirical intraperitoneal (IP) treatment with cefazolin and ceftazidime was started. The culture was positive for C. testosteroni and antibiotic was changed to ceftazidime IP. Four days after the ceftazidime treatment, the patient became asymptomatic. The follow-up culture from peritoneal effluent at 7th day was negative. This treatment was maintained for 21 days. After that, culture negative peritonitis occurred twice for 2 months in this patient, so CAPD catheter had to be removed. This is the first reported case of CAPD peritonitis caused by C. testosteroni. It is important for clinicians to recognize that CAPD peritonitis is caused by this organism which has been largely overlooked as a potential pathogen.
Subject(s)
Adult , Female , Humans , Abdominal Pain , Catheters , Cefazolin , Ceftazidime , Comamonas , Comamonas testosteroni , Follow-Up Studies , Peritoneal Dialysis , Peritoneal Dialysis, Continuous Ambulatory , PeritonitisABSTRACT
<p><b>OBJECTIVE</b>To investigate the characteristic and biochemical mechanism about the phenol biodegradation by bacterial strains ZD 4-1 and ZD 4-3.</p><p><b>METHODS</b>Bacterial strains ZD 4-1 and ZD 4-3 were isolated by using phenol as the sole source of carbon and energy, and identified by 16S rDNA sequence analysis. The concentrations of phenol and total organic carbon (TOC) were monitored to explore the degradation mechanism. The biodegradation intermediates were scanned at 375 nm by using a uv-vis spectrophotometer. The enzyme assays were performed to detect the activities of dioxygenases.</p><p><b>RESULTS</b>Bacterial strains ZD 4-1 and ZD 4-3 were identified as Comamonas testosteroni and Pseudomonas aeruginosa by 16S rDNA sequence analysis, respectively. The growth of the two strains was observed on a variety of aromatic hydrocarbons. The strains ZD 4-1 and ZD 4-3 metabolized phenol via ortho-pathways and meta-pathways, respectively. In addition, the results of enzyme assays showed that the biodegradation efficiency of phenol by meta-pathways was higher than that by ortho-pathways. Finally, the results of induction experiment indicated that the catechol dioxygenases, both catechol 1,2-dioxygenase (C120) and catechol 2,3-dioxygenase (C230), were all inducible.</p><p><b>CONCLUSION</b>The strains ZD 4-1 and ZD 4-3 metabolize phenol through ortho-pathways and meta-pathway, respectively. Furthermore, the biodegradation efficiency of phenol by meta-pathways is higher than that by ortho-pathways.</p>