- Assessing interactions, predicting function, and increasing degradation potential of a PAH-degrading bacterial consortium by effect of an inoculant strain. [Journal Article]
- ESEnviron Sci Pollut Res Int 2019 Jul 04
- A natural phenanthrene-degrading consortium CON was inoculated with an exogenous strain Sphingobium sp. (ex Sp. paucimobilis) 20006FA yielding the consortium called I-CON, in order to study ecologica…
A natural phenanthrene-degrading consortium CON was inoculated with an exogenous strain Sphingobium sp. (ex Sp. paucimobilis) 20006FA yielding the consortium called I-CON, in order to study ecological interactions into the bacterial community. DGGE and proteomic profiles and analyses by HTS (High-Throughput Sequencing) technologies demonstrated inoculant establishment and changes on CON composition. Inoculation increased degradation efficiency in I-CON and prevented intermediate HNA accumulation. This could be explained not only by the inoculation, but also by enrichment in Achromobacter genus at expense of a decrease in Klebsiella genus. After inoculation, cooperation between Sphingobium and Achromobacter genera were improved, thereby, some competition could have been generated, and as a consequence, species in minor proportion (cheaters), as Inquilinus sp. and Luteibacter sp., were not detected. Sequences of Sphingobium (corresponding to the inoculated strain) did not vary. PICRUSt predicted a network with bacterial phylotypes connected with enzymes, showing functional redundancy in the phenanthrene pathway, with exception of the first enzymes biphenyl-2,3-diol 1,2-dioxygenase and protocatechuate 4,5-dioxygenase that were only encoded in Sphingobium sp. This is the first report where a natural consortium that has been characterized by HTS technologies is inoculated with an exogenous strain in order to study competitiveness and interactions.
- Diversity of Achromobacter species recovered from patients with cystic fibrosis, in Argentina. [Journal Article]
- RARev Argent Microbiol 2019 Jun 25
- Different phenotype-based techniques and molecular tools were used to describe the distribution of different Achromobacter species in patients with cystic fibrosis (CF) in Argentina, and to evaluate …
Different phenotype-based techniques and molecular tools were used to describe the distribution of different Achromobacter species in patients with cystic fibrosis (CF) in Argentina, and to evaluate their antibiotic resistance profile. Phenotypic identification was performed by conventional biochemical tests, commercial galleries and MALDI-TOF MS. Genetic approaches included the detection of A. xylosoxidans specific marker blaoxa-114, the amplification and sequencing of the 16S rRNA gene, nrdA and blaOXA complete sequence, and MLST analysis. Phenotypic approaches, even MALDI-TOF, rendered inconclusive or misleading results. On the contrary, concordant results were achieved with the nrdA sequencing or sequence type (ST) analysis, and the complete blaOXA sequencing, allowing a reliable discrimination of different Achromobacter species. A. xylosoxidans accounted for 63% of Achromobacter infections and A. ruhlandii accounted for 17%. The remaining species corresponded to A. insuavis, A. dolens, A. marplatensis and A. pulmonis. Antimicrobial susceptibilities were determined by the agar dilution method according to CLSI guidelines. Piperacillin, piperacillin/tazobactam and carbapenems were the most active antibiotics. However, the emergence of carbapenem-resistant isolates was detected. In conclusion, prompt and accurate identification tools were necessary to determine that different Achromobacter species may colonize/infect the airways of patients with CF. Moreover, antimicrobial therapy should be administered based on the susceptibility profile of individual Achromobacter sp. isolates.
- Degradation mechanisms of sulfamethoxazole and its induction of bacterial community changes and antibiotic resistance genes in a microbial fuel cell. [Journal Article]
- BTBioresour Technol 2019 Jun 12; 289:121632
- In this study, more than 85.1% of sulfamethoxazole (SMX) could be degraded within 60 h. The strengthening of microbial metabolisms and the sustainment of electrical stimulation contributed to the rap…
In this study, more than 85.1% of sulfamethoxazole (SMX) could be degraded within 60 h. The strengthening of microbial metabolisms and the sustainment of electrical stimulation contributed to the rapid removal of SMX in microbial fuel cells (MFCs). High-performance liquid chromatography identified that SMX could be thoroughly degraded into less harmful alcohols and methane after the MFC processing. In addition, the major role of Shewanella sp. and Geobacteria sp. in power generation, and the promotion of Alcaligenes, Pseudomonas and Achromobacter in SMX degradation have been demonstrated. Moreover, this study further proved that the copy numbers of targeted antibiotic resistance genes and integrons produced in MFCs were much lower than those found in conventional wastewater treatment plants; MFCs seem to be a promising alternative to reduce antibiotics in wastewater treatment and water purification.
- Key extracellular enzymes triggered high-efficiency composting associated with bacterial community succession. [Journal Article]
- BTBioresour Technol 2019; 288:121576
- A consortium of key bacterial taxa plays critical roles in the composting process. In order to elucidate the identity and mechanisms by which specific bacterial species drive high-efficiency composti…
A consortium of key bacterial taxa plays critical roles in the composting process. In order to elucidate the identity and mechanisms by which specific bacterial species drive high-efficiency composting, the succession of key bacterial consortia and extracellular enzymes produced during the composting process were monitored in composting piles with varying initial C/N ratios. Results showed that C/N ratios of 25 and 35 enhanced composting efficiency through elevated temperatures, higher germination indices, enhanced cellulose and hemicellulose degradation, and higher cellulase and dehydrogenase activities. The activities of cellulase and β-glucosidase, cellulase and protease, and cellulase and β-glucosidase exhibited significant relationships with bacterial community composition within the mesophilic, thermophilic, and mature phases, respectively. Putative key taxa, linked to a higher composting efficiency, such as Nonomuraea, Desemzia, Cellulosimicrobium, Virgibacillus, Clostridium, and Achromobacter, exhibited significantly positive relationships with extracellular enzyme activities, suggesting a significant contribution to these taxa to the development of composting maturity.
- Is the Potable Water System an Advantageous Preinfection Niche for Bacteria Colonizing the Cystic Fibrosis Lung? [Journal Article]
- MBIOMBio 2019 Jun 04; 10(3)
- People with cystic fibrosis are susceptible to lung infections from a variety of bacteria, a number of which also reside in the potable water system, including Pseudomonas aeruginosa, Stenotrophomona…
People with cystic fibrosis are susceptible to lung infections from a variety of bacteria, a number of which also reside in the potable water system, including Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Burkholderia cepacia complex, and nontuberculosis Mycobacteria Here, I propose chemical and physical aspects of the potable water system along with bacterial lifestyle strategies in this system that may enhance successful colonization of cystic fibrosis lungs by these bacteria, including iron and copper levels, lipids, and low growth rates within low-oxygen biofilms.
- Statistical and sequential (fill-and-draw) approach to enhance rhamnolipid production using industrial lignocellulosic hydrolysate C6 stream from Achromobacter sp. (PS1). [Journal Article]
- BTBioresour Technol 2019; 288:121494
- Statistical optimization using industrial rice-straw hydrolysate (C6 stream) containing 5.0% total sugars was carried out for enhancing the rhamnolipid production from Achromobacter sp. (PS1) with su…
Statistical optimization using industrial rice-straw hydrolysate (C6 stream) containing 5.0% total sugars was carried out for enhancing the rhamnolipid production from Achromobacter sp. (PS1) with subsequent adoption of a sequential fermentation approach with fill-and-draw operation for further increment. The interactive effects of six influential variables obtained from one-factor-at-a-time approach as sodium nitrate, yeast extract, ferrous sulphate, phosphate concentrations and agitation in presence of lignocellulosic hydrolyzed sugars as a basal medium using central composite design revealed the experimental rhamnolipid yield of 5.46 g/L at optimum conditions of total sugars 40 g/L (w/v), sodium nitrate 6.0 (g/L), yeast extract 2 (g/L), ferrous sulphate 0.2 (mg/L) and phosphate 1000 mM at 100 rpm at 30 °C in 8 days. The sequential approach further resulted in an overall yield of 19.35 g/L of rhamnolpid in five sequential-cycles with an increase of 258% over the batch process on account of nutrients replenishment and dilution of toxic by-products.
- A PAH-degrading bacterial community enriched with contaminated agricultural soil and its utility for microbial bioremediation. [Journal Article]
- EPEnviron Pollut 2019; 251:773-782
- A bacterial community was enriched with polycyclic aromatic hydrocarbons (PAHs) polluted soil to better study PAH degradation by indigenous soil bacteria. The consortium degraded more than 52% of low…
A bacterial community was enriched with polycyclic aromatic hydrocarbons (PAHs) polluted soil to better study PAH degradation by indigenous soil bacteria. The consortium degraded more than 52% of low molecular weight and 35% of high molecular weight (HMW) PAHs during 16 days in a soil leachate medium. 16S rRNA gene high-throughput sequencing and quantitative polymerase chain reaction analyses for alpha subunit genes of ring-hydroxylating-dioxygenase (RHDα) suggested that Proteobacteria and Actinobacteria at the phylum level, Pseudomonas, Methylobacillus, Nocardioides, Methylophilaceae, Achromobacter, Pseudoxanthomonas, and Caulobacter at the generic level were involved in PAH degradation and might have the ability to carry RHDα genes (nidA and nahAc). The community was selected and collected according to biomass and RHDα gene contents, and added back to the PAH-polluted soil. The 16 EPA priority PAHs decreased from 95.23 to 23.41 mg kg-1 over 35 days. Compared with soil without the introduction of this bacterial community, adding the community with RHDα genes significantly decreased soil PAH contents, particularly HMW PAHs. The metabolic rate of PAHs in soil was positively correlated with nidA and nahAc gene contents. These results indicate that adding an indigenous bacterial consortium containing RHDα genes to contaminated soil may be a feasible and environmentally friendly method to clean up PAHs in agricultural soil.
- Effects of dietary poly-β-hydroxybutyrate supplementation on the growth, immune response and intestinal microbiota of soiny mullet (Liza haematocheila). [Journal Article]
- FSFish Shellfish Immunol 2019; 91:251-263
- Soiny mullet (Liza haematocheila) is an important economic fish species in China, but stress and diseases have seriously restricted its culture. There are no effective methods including vaccines to p…
Soiny mullet (Liza haematocheila) is an important economic fish species in China, but stress and diseases have seriously restricted its culture. There are no effective methods including vaccines to prevent or control these diseases. Alternative methods should be employed, such as using novel immunostimulant poly-β-hydroxybutyrate (PHB). The present study aimed to evaluate effects of dietary PHB supplementation on the growth, antioxidant enzymes activity, immune-related genes expression and intestinal microbiota in soiny mullet. The fish was fed for 30 or 60 days with six diets at different PHB supplementation of 0, 0.5, 1, 2, 4 and 8%, named as groups P0, P0.5, P1, P2, P4 and P8. The results showed that the weight gain and specific growth rate of fish in P2 and P0.5 groups were significantly higher than those in control P0 group at 30 and 60 days, respectively (P < 0.05). The antioxidant enzymes activity of catalase and superoxide dismutase in serum were significantly increased in P0.5/P1/P2 groups after 30 days. The transcriptional levels of penicillin-binding protein A and interleukin-8 analyzed by qRT-PCR were significantly upregulated in P2 and P4 groups compared to those in P0/P0.5/P1/P8 groups at 30 days. The transcriptional level of major histocompatibility complex class II in P2 group was significantly upregulated, and aldehyde oxidase downregulated compared to P0 group. Intestinal microbiota analysis by Illumina high-throughput sequencing showed that the microbiota diversity was not changed significantly, but the microbiota structure shifted significantly post PHB treatment. At the phyla level, Firmicutes and Proteobacteria were predominant in both P0 and P2 groups. At the genus level, the relative abundance of Bacillus spp. in P2 group increased significantly, and abundance of Achromobacter spp. decreased significantly. KEGG pathway analysis by PICRUSt showed that oral administration PHB significantly upregulated abundances of genes responsible for 10 pathways and downregulated genes involved in 17 pathways. In conclusion, soiny mullet fed with 2% PHB supplemental diets for 30 days showed better growth performance, higher antioxidant enzymes activity and immune-related genes expression. Their regulation of growth and immunity might be related with the intestinal microbiota change post PHB supplementation. It will provide very useful basic information to study the regulation mechanism of PHB in aquatic animals, and provide good green method to prevent disease in soiny mullet.
- Study of 109 Achromobacter spp. isolates from 9 French CF centres reveals the circulation of a multiresistant clone of A. xylosoxidans belonging to ST 137. [Journal Article]
- JCJ Cyst Fibros 2019 May 16
- We previously reported the distribution of Achromobacter spp. (species and Sequence Types (ST)) in our French Cystic Fibrosis (CF) centre. In the present study we collected 109 Achromobacter isolates…
We previously reported the distribution of Achromobacter spp. (species and Sequence Types (ST)) in our French Cystic Fibrosis (CF) centre. In the present study we collected 109 Achromobacter isolates (1/patient) from 9 other French CF Centres for species identification, antimicrobial susceptibility testings and Multilocus-Sequence-Typing (MLST) analysis. Ten species were detected, A. xylosoxidans being the most predominant one (73.4% of the isolates). Piperacillin-tazobactam, ceftazidime, imipenem, meropenem and ciprofloxacin were respectively active against 88, 70, 79, 72 and 23% of the isolates. Among the 79 A. xylosoxidans isolates, 46 STs were detected. Interestingly, ST 137, recovered in 4 centres (5 patients), was previously detected in our centre (2 patients). The strains from the 7 patients belonged to the same pulsotype (pulsed-field-gel-electrophoresis analysis) and harboured acquired resistance to meropenem, ceftazidime, ciprofloxacin, and except for 2 isolates, to imipenem and piperacillin-tazobactam. This is the first description in France of a circulating multiresistant A. xylosoxidans strain.
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- IPIndian Pediatr 2019 May 15; 56(5):423-425
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