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Infection and Drug Resistance 2021To investigate the genomic and plasmid characteristics of a newly discovered strain with a -carrying plasmid and novel integron In isolated from a cerebrospinal fluid...
PURPOSE
To investigate the genomic and plasmid characteristics of a newly discovered strain with a -carrying plasmid and novel integron In isolated from a cerebrospinal fluid specimen in a teaching hospital.
METHODS
Species identification was performed by MALDI-TOF MS, and was identified by PCR and Sanger sequencing. Whole-genome sequencing analysis was conducted using the Illumina NovaSeq 6000 and Oxford Nanopore platforms. Integron detection was performed using INTEGRALL. The phylogenetic tree was constructed by using kSNP3.0. Plasmid characteristics were assessed by S1-pulsed-field gel electrophoresis (S1-PFGE), Southern blotting, conjugation experiments, and whole-genome sequencing analysis. Comparative genomics analysis of the plasmid and genetic context of were conducted by using BLAST Ring Image Generator (BRIG) and Easyfig 2.3, respectively.
RESULTS
ZDHY95, an MDR strain of harboring , was identified. It was sensitive only to amikacin and was resistant to carbapenems, β-lactams, aztreonam, fluoroquinolones, and aminoglycosides. Joint S1-PFGE, Southern blot, conjugation assay, and whole-genome sequencing experiments confirmed that the gene was located within class I integron In of the plasmid and that the surrounding genetic environment was 5'CS- --3'CS. The novel class I integron In was detected on the chromosome of ZDHY95, and the gene cassette array was 5'CS- --3'CS. Phylogenetic analysis showed that antimicrobial resistance gene-carrying isolates were divided into two clusters, mainly containing isolates from the USA and Pakistan.
CONCLUSION
A novel -carrying conjugative plasmid, pZDHY95-VIM-2, was reported for the first time in , elucidating the genetic environment and transfer mechanism. The gene structure of the novel class I integron In was also clarified. We explored the phylogenetic relationship of with drug resistance genes and suggested that with metallo-β-lactamases (MBLs) in the hospital environment may cause infection in patients with long-term intubation or after interventional surgery.
PubMed: 34466007
DOI: 10.2147/IDR.S320294 -
Genes May 2022A1501, a plant-associated diazotrophic bacterium, prefers to conform to a nitrogen-fixing biofilm state under nitrogen-deficient conditions. The extracytoplasmic...
A1501, a plant-associated diazotrophic bacterium, prefers to conform to a nitrogen-fixing biofilm state under nitrogen-deficient conditions. The extracytoplasmic function (ECF) sigma factor AlgU is reported to play key roles in exopolysaccharide (EPS) production and biofilm formation in the genus; however, the function of AlgU in A1501 is still unclear. In this work, we mainly investigated the role of in EPS production, biofilm formation and nitrogenase activity in A1501. The mutant Δ showed a dramatic decrease both in the EPS production and the biofilm formation capabilities. In addition, the biofilm-based nitrogenase activity was reduced by 81.4% in the Δ mutant. The transcriptional level of , a key Psl-like (a major EPS in A1501) synthesis-related gene, was almost completely inhibited in the mutant and was upregulated by 2.8-fold in the -overexpressing strain. A predicted AlgU-binding site was identified in the promoter region of . The DNase I footprinting assays indicated that AlgU could directly bind to the promoter, and β-galactosidase activity analysis further revealed mutations of the AlgU-binding boxes drastically reduced the transcriptional activity of the promoter; moreover, we also demonstrated that AlgU was positively regulated by RpoN at the transcriptional level and negatively regulated by the RNA-binding protein RsmA at the posttranscriptional level. Taken together, these data suggest that AlgU promotes EPS production and nitrogen-fixing biofilm formation by directly activating the transcription of , and the expression of AlgU is controlled by RpoN and RsmA at different regulatory levels.
Topics: Bacterial Proteins; Biofilms; Gene Expression Regulation, Bacterial; Nitrogen; Nitrogenase; Pseudomonas stutzeri; Sigma Factor
PubMed: 35627252
DOI: 10.3390/genes13050867 -
Microorganisms Jan 2023Paracetamol is one of the most used pharmaceuticals worldwide, but due to its widespread use it is detected in various environmental matrices, such as surface and ground...
Paracetamol is one of the most used pharmaceuticals worldwide, but due to its widespread use it is detected in various environmental matrices, such as surface and ground waters, sediments, soils or even plants, where it is introduced mainly from the discharge of wastewater and the use of sewage sludge as fertilizer in agriculture. Its accumulation in certain organisms can induce reproductive, neurotoxic or endocrine disorders, being therefore considered an emerging pollutant. This study reports on the isolation, from sewage sludge produced in wastewater treatment plants (WWTPs), of bacterial strains capable of degrading paracetamol. Up to 17 bacterial strains were isolated, but only two of them, identified as CSW02 and CSW01, were able to degrade very high concentrations of paracetamol in solution as a sole carbon and energy source, and none of them had been previously described as paracetamol degraders. These bacteria showed the ability to degrade up to 500 mg L of paracetamol in only 6 and 4 h, respectively, much quicker than any other paracetamol-degrader strain described in the literature. The two main paracetamol metabolites, 4-aminophenol and hydroquinone, which present high toxicity, were detected during the degradation process, although they disappeared very quickly for paracetamol concentrations up to 500 mg L. The IC of paracetamol for the growth of these two isolates was also calculated, indicating that CSW01 was more tolerant than CSW02 to high concentrations of paracetamol and/or its metabolites in solution, and this is the reason for the much lower paracetamol degradation by CSW02 at 2000-3000 mg L. These findings indicate that both bacteria are very promising candidates for their use in paracetamol bioremediation in water and sewage sludge.
PubMed: 36677487
DOI: 10.3390/microorganisms11010196 -
Iranian Journal of Microbiology Apr 2020Excess use of pesticides in agricultural field not only compromised soil fertility but also posed serious threat to water bodies and life in the surrounding environment....
BACKGROUND AND OBJECTIVES
Excess use of pesticides in agricultural field not only compromised soil fertility but also posed serious threat to water bodies and life in the surrounding environment. The leftover pesticide residue needs to be remediated effectively. Compared to physical, chemical and enzymatic remediation options the microbial remediation is more practical and sustainable.
MATERIALS AND METHODS
The smk strain was found to use dichlorvos as the solitary carbon source. Minimal medium supplemented with dichlorvos was used to test ability of bacterium to degrade pesticide aerobically. The metabolites produced by the bacterium were studied with UV-Vis spectrophotometry, HPLC, FTIR and GC-MS techniques. The toxicity studies of neat dichlorvos and smk degraded metabolites were studied by subcutaneous injection in .
RESULTS
The smk strain was found to degrade as high as 80% of dichlorvos on 7 day of incubation, at 30 °C temperature and at pH 7. In five steps complete aerobic degradation of 2,2dicholorvinyl dimethyl phosphate (dichlorvos) resulted in production of free methyl and phosphate. The degradation intermediates produced are 2-Chlorovinyl dimethyl phosphate, vinyl dimethyl phosphate, dimethyl phosphate, methylphosphate and finally free phosphate. The histopathological analysis of liver, spleen and thymus of s were performed to study toxicity of dichlorvos and degraded metabolites.
CONCLUSION
smk could result highest aerobic degradation of dichlorvos to produce free methyl and phosphate. Degradation metabolites could reverse largely toxic effects of dichlorvos when studied in .
PubMed: 32494348
DOI: No ID Found -
Iranian Journal of Microbiology Dec 2022Dental caries is a breakdown of the teeth enamel due to harmful bacteria, lack of oral hygiene, and sugar consumption. The acid-producing bacterium is the leading cause...
BACKGROUND AND OBJECTIVES
Dental caries is a breakdown of the teeth enamel due to harmful bacteria, lack of oral hygiene, and sugar consumption. The acid-producing bacterium is the leading cause of dental caries. Dextranase is an enzyme that can degrade dextran to low molecular weight fractions, which have many therapeutic and industrial applications. The purpose of the present study was to isolate a novel dextranase-producing bacteria from a source (molasses). The cell-free extracts containing dextranases were tested as antibiofilm agents.
MATERIALS AND METHODS
Dextranase-producing bacteria were identified using phenotypic and genotypic methods such as 16S rRNA gene sequencing and enzymatic characterization.
RESULTS
The highest six dextranase-producing bacterial isolates were species. The best conditions for dextranase productivity were obtained after 72 hours of culture time at pH 7. The addition of glucose to the medium enhanced the production of the enzymes. The cell-free extract of the six most active isolates showed remarkable activity against biofilm formation by ATCC 25175. The highest inhibition activities reached 60% and 80% for and respectively.
CONCLUSION
Therefore, our study added to the current dextranase-producing bacteria with potential as a source of dextranases.
PubMed: 36721450
DOI: 10.18502/ijm.v14i6.11260 -
Biochemistry and Biophysics Reports Sep 2015A pirin-like protein from a marine denitrifying bacterium, Zobell has been heterologously expressed in and purified to homogeneity with metal-affinity and gel...
A pirin-like protein from a marine denitrifying bacterium, Zobell has been heterologously expressed in and purified to homogeneity with metal-affinity and gel filtration chromatographies. The recombinant pirin-like protein has exhibited quercetinase activities upon the incorporation of a divalent metal ion, while its biological role remains unclear. In the case of Cu the holo-protein demonstrated the highest activities and spectroscopic properties typical of type II Cu protein. A 3D-structual model constructed using the crystal structure of human pirin as temperate indicated that the metal biding site is constructed with 3His1Glu located in the consensus sequences in the N-terminal domain.
PubMed: 29124178
DOI: 10.1016/j.bbrep.2015.08.001 -
BMC Microbiology Nov 2016Microbial antimonite [Sb(III)] oxidation converts toxic Sb(III) into less toxic antimonate [Sb(V)] and plays an important role in the biogeochemical Sb cycle. Currently,...
BACKGROUND
Microbial antimonite [Sb(III)] oxidation converts toxic Sb(III) into less toxic antimonate [Sb(V)] and plays an important role in the biogeochemical Sb cycle. Currently, little is known about the mechanisms underlying bacterial Sb(III) resistance and oxidation.
RESULTS
In this study, Tn5 transposon mutagenesis was conducted in the Sb(III)-oxidizing strain Pseudomonas stutzeri TS44 to isolate the genes responsible for Sb(III) resistance and oxidation. An insertion mutation into gshA, encoding a glutamate cysteine ligase involved in glutathione biosynthesis, generated a strain called P. stutzeri TS44-gshA. This mutant strain was complemented with a plasmid carrying gshA to generate strain P. stutzeri TS44-gshA-C. The transcription of gshA, the two superoxide dismutase (SOD)-encoding genes sodB and sodC as well as the catalase-encoding gene katE was monitored because gshA-encoded glutamate cysteine ligase is responsible for the biosynthesis of glutathione (GSH) and involved in the cellular stress defense system as are superoxide dismutase and catalase responsible for the conversion of ROS. In addition, the cellular content of total ROS and in particular HO was analyzed. Compared to the wild type P. stutzeri TS44 and TS44-gshA-C, the mutant P. stutzeri TS44-gshA had a lower GSH content and exhibited an increased content of total ROS and HO and increased the Sb(III) oxidation rate. Furthermore, the transcription of sodB, sodC and katE was induced by Sb(III). A positive linear correlation was found between the Sb(III) oxidation rate and the HO content (R = 0.97), indicating that the accumulated HO is correlated to the increased Sb(III) oxidation rate.
CONCLUSIONS
Based on the results, we propose that a disruption of the pathway involved in ROS-protection allowed HO to accumulate. In addition to the previously reported enzyme mediated Sb(III) oxidation, the mechanism of bacterial oxidation of Sb(III) to Sb(V) includes a non-enzymatic mediated step using HO as the oxidant.
Topics: Antimony; Bacterial Proteins; Catalase; DNA Transposable Elements; Gene Expression Regulation, Bacterial; Genes, Bacterial; Glutamate-Cysteine Ligase; Glutathione; Hydrogen Peroxide; Mutagenesis; Mutation; Oxidants; Oxidation-Reduction; Pseudomonas stutzeri; Reactive Oxygen Species; Stress, Psychological; Superoxide Dismutase
PubMed: 27884113
DOI: 10.1186/s12866-016-0902-5 -
Applied and Environmental Microbiology Apr 1983A comparison was made of denitrification by Pseudomonas stutzeri, Pseudomonas aeruginosa, and Paracoccus denitrificans. Although all three organisms reduced nitrate to... (Comparative Study)
Comparative Study
A comparison was made of denitrification by Pseudomonas stutzeri, Pseudomonas aeruginosa, and Paracoccus denitrificans. Although all three organisms reduced nitrate to dinitrogen gas, they did so at different rates and accumulated different kinds and amounts of intermediates. Their rates of anaerobic growth on nitrate varied about 1.5-fold; concomitant gas production varied more than 8-fold. Cell yields from nitrate varied threefold. Rates of gas production by resting cells incubated with nitrate, nitrite, or nitrous oxide varied 2-, 6-, and 15-fold, respectively, among the three species. The composition of the gas produced also varied markedly: Pseudomonas stutzeri produced only dinitrogen; Pseudomonas aeruginosa and Paracoccus denitrificans produced nitrous oxide as well; and under certain conditions Pseudomonas aeruginosa produced even more nitrous oxide than dinitrogen. Pseudomonas stutzeri and Paracoccus denitrificans rapidly reduced nitrate, nitrite, and nitrous oxide and were able to grow anaerobically when any of these nitrogen oxides were present in the medium. Pseudomonas aeruginosa reduced these oxides slowly and was unable to grow anaerobically at the expense of nitrous oxide. Furthermore, nitric and nitrous oxide reduction by Pseudomonas aeruginosa were exceptionally sensitive to inhibition by nitrite. Thus, although it has been well studied physiologically and genetically, Pseudomonas aeruginosa may not be the best species for studying the later steps of the denitrification pathway.
Topics: Kinetics; Nitrates; Nitrites; Nitrogen; Nitrous Oxide; Oxidation-Reduction; Paracoccus denitrificans; Pseudomonas; Pseudomonas aeruginosa
PubMed: 6407395
DOI: 10.1128/aem.45.4.1247-1253.1983 -
Indian Journal of Ophthalmology Jan 2020We report a rare case of Pseudomonas stutzeri endophthalmitis in an immunocompetent individual along with the review of the literature. A 39-year-old healthy lady... (Review)
Review
We report a rare case of Pseudomonas stutzeri endophthalmitis in an immunocompetent individual along with the review of the literature. A 39-year-old healthy lady presented with sudden painful loss of vision in her right eye. She was diagnosed with postcataract surgery acute endophthalmitis and underwent vitrectomy, intraocular lens explantation and intravitreal antibiotics. P. stutzeri was isolated from vitreous. Though the infection was controlled, the anatomy of the eye could not be salvaged and the right eye became phthisical. P. stutzeri is a rare cause of endophthalmitis with usually poor outcomes.
Topics: Adult; Cataract Extraction; Endophthalmitis; Eye Infections, Bacterial; Female; Humans; Pseudomonas Infections; Pseudomonas stutzeri
PubMed: 31856535
DOI: 10.4103/ijo.IJO_334_19 -
3 Biotech Oct 2017The present study focuses on the optimization of biosurfactant (BS) production using two potential biosurfactant producer NA3 and MN3 and role of enzymes in the...
The present study focuses on the optimization of biosurfactant (BS) production using two potential biosurfactant producer NA3 and MN3 and role of enzymes in the biodegradation of crude oil. The optimal conditions for NA3 and MN3 for biodegradation were pH of 8 and 7; temperature of 30 and 40 °C, respectively. NA3 and MN3 produced 3.81 and 4.68 g/L of BS, respectively. Gas chromatography mass spectrometry confirmed that BS was mainly composed of fatty acids. Furthermore, the role of the degradative enzymes, alkane hydroxylase, alcohol dehydrogenase and laccase on biodegradation of crude oil are explained. Maximum biodegradation efficiency (BE) was recorded for mixed consortia (86%) followed by strain NA3 (84%). Both bacterial strains were found to be vigorous biodegraders of crude oil than other biosurfactant-producing bacteria due to their enzyme production capabilities and our results suggests that the bacterial isolates can be used for effective degradation of crude oil within short time periods.
PubMed: 28794933
DOI: 10.1007/s13205-017-0902-7