Authors: Supriya V Bhat, Heather Maughan, Andrew D S Cameron...

is a diverse betaproteobacterial genus with many strains having agricultural and industrial relevance, including plant-growth promotion, bioremediation of hydrocarbon-contaminated soils, and heavy metal immobilization. spp. are broadly distributed in the environment, and have been isolated from plant hosts as well as healthy and diseased animal hosts, yet the genetic basis of this ecological versatility has not been characterized. Here, we present a phylogenomic comparison of published genomes and show that the genus is divided into two well-supported clades: one '' clade with isolates from soils and plant rhizospheres, and a second ' and ' clade with isolates from humans and sludge. The pan-genome inferred from 61 genomes contained over 28 000 genes, of which only 884 were found in all genomes. Analysis of industrially relevant functions highlighted the ecological versatility of and supported their role as generalists.

Topics: Animals; DNA, Bacterial; Delftia; Humans; Metals, Heavy; Phylogeny; Sequence Analysis, DNA; Sewage; Soil

PubMed: 36107145
DOI: 10.1099/mgen.0.000864

Review

Authors: Vincenzo Scaglione, Lucia Federica Stefanelli, Maria Mazzitelli...

() is a non-fermentative, aerobic, Gram-negative bacillus typically found in environmental sources such as soil and water. Although considered an opportunistic pathogen, it has been implicated in both immunocompromised and immunocompetent individuals. This study presents a case of persistent cathether-related bacteraemia in a 61-year-old haemodialysis patient and offers a systematic literature review of similar cases. The patient, affected by end-stage kidney disease and dependent on a central venous catheter (CVC), presented with septic shock. Blood cultures confirmed , resistant to aminoglycosides but sensitive to cephalosporins, piperacillin/tazobactam, and fluoroquinolones. Despite appropriate antibiotic therapy, bacteraemia persisted, prompting the use of taurolidine lock therapy when catheter removal was initially unfeasible. Blood cultures cleared after nine days, and the catheter was later replaced. A systematic review following PRISMA guidelines identified 21 additional cases of bacteraemia. Most (76.2%) occurred in immunocompromised patients, particularly those with malignancies, chronic haemodialysis, or indwelling devices. Infections in immunocompetent individuals were typically associated with intravenous drug use or environmental exposure. Mortality was approximately 19%. Aminoglycoside resistance was consistent across most cases, while susceptibility to piperacillin/tazobactam, cephalosporins, and carbapenems was generally preserved. Given its resistance profile and ability to form biofilms, D. acidovorans poses a management challenge, particularly in catheter-associated infections. Rapid identification and targeted antimicrobial therapy are crucial. Adjunctive measures such as taurolidine lock therapy can be beneficial when device removal is not immediately possible.

PubMed: 40298489
DOI: 10.3390/antibiotics14040365

Authors: Tofazzal Islam, Fatema, M Nazmul Hoque...

Plant probiotic bacteria enhance growth and yield of crop plants when applied at the appropriate time and dose. Two rice probiotic bacteria, strain BRRh-4 and sp. strain BTL-M2 promote growth and yield of plants. However, no information is available on application of these two bacteria on growth, yield, and diversity and population of bacteriome in roots and rhizosphere soils of the treated rice plants. This study aimed to assess the effect of BRRh-4 and BTL-M2 application on growth, yield and bacteriome in roots and rhizosphere soil of rice under varying doses of N, P and K fertilizers. Application of BRRh-4 and BTL-M2 strains significantly ( < 0.05) increased seed germination, growth and yield of rice compared to an untreated control. Interestingly, the grain yield of rice by these bacteria with 50% less of the recommended doses of N, P, and K fertilizers were statistically similar to or better than the rice plants treated with 100% doses of these fertilizers. Targeted amplicon (16S rRNA) sequence-based analysis revealed significant differences (PERMANOVA,  = 0.00035) in alpha-diversity between the root (R) and rhizosphere soil (S) samples, showing higher diversity in the microbial ecosystem of root samples. Additionally, the bacteriome diversity in the root of rice plants that received both probiotic bacteria and chemical fertilizers were significantly higher (PERMANOVA,  = 0.0312) compared to the rice plants treated with fertilizers only. Out of 185 bacterial genera detected, , an anaerobic and Gram-negative bacterium, was found to be the predominant genus in both rhizosphere soil and root metagenomes. However, the relative abundance of remained two-fold higher in the rhizosphere soil metagenome (52.02%) than in the root metagenome (25.04%). The other predominant bacterial genera detected in the rice root metagenome were (11.07%), (4.06%), (3.91%), (2.97%), (2.61%), and (2.30%). On the other hand, rhizosphere soil metagenome had (12.38%), (9.50%), (5.94%), (3.40%), and (3.02%). Interestingly, we found the presence and/or abundance of specific genera of bacteria in rice associated with the application of a specific probiotic bacterium. Taken together, our results indicate that improvement of growth and yield of rice by strain BRRh-4 and sp. strain BTL-M2 is likely linked with modulation of diversity, structures, and signature of bacteriome in roots and rhizosphere soils. This study for the first time demonstrated that application of plant growth promoting bacteria significantly improve growth, yield and increase the diversity of bacterial community in rice.

PubMed: 37520368
DOI: 10.3389/fmicb.2023.1212505

Review

Authors: Alexandre Ranc, Grégory Dubourg, Pierre Edouard Fournier...

Delftia tsuruhatensis, which was first isolated in environmental samples, was rarely associated with human infections. We report on pneumonia caused by D. tsuruhatensis in an infant who underwent cardiac surgery. Retrospective analyses detected 9 other isolates from 8 patients. D. tsuruhatensis is an emergent pathogen, at least for immunocompromised patients.

Topics: Communicable Diseases, Emerging; Cross Infection; Delftia; France; Gram-Negative Bacterial Infections; Humans; Infant; Opportunistic Infections

PubMed: 29460754
DOI: 10.3201/eid2403.160939

Authors: Signe Marie Mehl Højgaard, Omid Rezahosseini, Jenny Dahl Knudsen...

Delftia acidovorans () is a Gram-negative bacteria and an uncommon cause of human infections. This retrospective cohort study investigated clinical and microbiological characteristics and outcomes of patients with infections. We included patients with culture-confirmed infections attending Rigshospitalet, during 2002-2020. Fifty-nine patients with a median interquartile ranges (IQR) age of 47 (15-67) years were included. Thirty-five (59%) were males, and 57 (97%) had at least one comorbidity, including 25 (42%) with solid or hematologic malignancies. Eight (14%) were admitted to ICU, and 15 (25%) died within 365 days after infection. Persistent infection was found in 4 (6.8%) patients, and 41 (70%) had polymicrobial cultures, mainly with Pseudomonas spp. and Stenotrophomonas maltophilia. More than 85% of the isolates were susceptible to meropenem or ceftazidime. Although, 88% and 62% of the isolates were resistant to gentamicin and colistin, respectively. infections mainly affect patients with preexisting comorbidities, including malignancies. In the first year, all-cause mortality is considerable, polymicrobial cultures are common, and meropenem or cephalosporins with antipseudomonal activity could be the antibiotics of choice. Delftia acidovorans () is a Gram-negative bacteria that can cause infection in immunocompetent and immunocompromised individuals. The current knowledge comes mainly from case reports and case series. In this retrospective cohort study, we found that infections mainly affect male patients with preexisting comorbidities, including malignancies. Persistent infections were not common, and most of the patients had polymicrobial cultures, mainly with Pseudomonas spp. and Stenotrophomonas maltophilia. More than 85% of the isolates were susceptible to meropenem or ceftazidime. In contrast, 88% and 62% of the isolates were resistant to gentamicin and colistin, respectively.

Topics: Adolescent; Adult; Aged; Anti-Bacterial Agents; Ceftazidime; Colistin; Delftia acidovorans; Female; Gentamicins; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Male; Meropenem; Microbial Sensitivity Tests; Middle Aged; Retrospective Studies; Stenotrophomonas maltophilia; Young Adult

PubMed: 35862984
DOI: 10.1128/spectrum.00326-22

Authors: Yamini Jangir, Sarah French, Lily M Momper...

Continental subsurface environments can present significant energetic challenges to the resident microorganisms. While these environments are geologically diverse, potentially allowing energy harvesting by microorganisms that catalyze redox reactions, many of the abundant electron donors and acceptors are insoluble and therefore not directly bioavailable. Extracellular electron transfer (EET) is a metabolic strategy that microorganisms can deploy to meet the challenges of interacting with redox-active surfaces. Though mechanistically characterized in a few metal-reducing bacteria, the role, extent, and diversity of EET in subsurface ecosystems remains unclear. Since this process can be mimicked on electrode surfaces, it opens the door to electrochemical techniques to enrich for and quantify the activities of environmental microorganisms in situ. Here, we report the electrochemical enrichment of microorganisms from a deep fractured-rock aquifer in Death Valley, CA, USA. In experiments performed in mesocosms containing a synthetic medium based on aquifer chemistry, four working electrodes (WEs) were poised at different redox potentials (272, 373, 472, 572 mV vs. SHE) to serve as electron acceptors, resulting in anodic currents coupled to the oxidation of acetate during enrichment. The anodes were dominated by Betaproteobacteria from the families Comamonadaceae and Rhodocyclaceae. A representative of each dominant family was subsequently isolated from electrode-associated biomass. The EET abilities of the isolated Delftia strain (designated WE1-13) and Azonexus strain (designated WE2-4) were confirmed in electrochemical reactors using WEs poised at 522 mV vs. SHE. The rise in anodic current upon inoculation was correlated with a modest increase in total protein content. Both genera have been previously observed in mixed communities of microbial fuel cell enrichments, but this is the first direct measurement of their electrochemical activity. While alternate metabolisms (e.g., nitrate reduction) by these organisms were previously known, our observations suggest that additional 'hidden' interactions with external electron acceptors are also possible. Electrochemical approaches are well positioned to dissect such extracellular interactions that may be prevalent in the subsurface.

PubMed: 27242768
DOI: 10.3389/fmicb.2016.00756

Authors: Fan Feng, Yonghai Jiang, Yongfeng Jia...

The potential release capacity of arsenic (As) from sediment was evaluated under a high level of exogenous organic matter (EOM) with both bioreactive and chemically reactive organic matters (OMs). The OMs were characterized by FI, HIX, BIX, and SUVA fluorescence indices showing the biological activities were kept at a high level during the experimental period. At the genus level, Fe/Mn/As-reducing bacteria (, , , and ) and bacteria (, , , and ) that can participate in metabolic transformation using EOM were identified. The reducing condition occurs which promoted As, Fe, and Mn releases at very high concentrations of OM. However, As release increased during the first 15-20 days, followed by a decline contributed by secondary iron precipitation. The degree of As release may be limited by the reactivity of Fe (hydro)oxides. The EOM infiltration enhances As and Mn releases in aqueous conditions causing the risk of groundwater pollution, which could occur in specific sites such as landfills, petrochemical sites, and managed aquifer recharge projects.

PubMed: 36896144
DOI: 10.1016/j.ese.2023.100243

Authors: Gu Gong, Yingying Hong, Xuemei Wang...

Bacterial symbionts exhibiting co-evolutionary patterns with insect hosts play a vital role in the nutrient synthesis, metabolism, development, reproduction, and immunity of insects. The brown planthopper (BPH) has a strong ability to adapt to various environmental stresses and can develop resistance to broad-spectrum insecticides. We aimed to investigate whether gut symbionts of BPH play a major role in the detoxification of insecticides and host fitness in unfavorable environments. Nicotine-treated rice plants were exposed to BPH (early stage) and the gut microbiome of the emerging female adults were analyzed using high throughput sequencing (HTS). Nicotine administration altered the diversity and community structure of BPH symbionts with significant increases in bacterial members such as Microbacteriaceae, Comamondaceae, Enterobacteriaceae, and these changes may be associated with host survival strategies in adverse environments. Furthermore, the in-vitro study showed that four intestinal bacterial strains of BPH (Enterobacter NLB1, Bacillus cereus NL1, Ralstonia NLG26, and Delftia NLG11) could degrade nicotine when grown in a nicotine-containing medium, with the highest degradation (71%) observed in Delftia NLG11. RT-qPCR and ELISA analysis revealed an increased expression level of CYP6AY1 and P450 enzyme activities in Delftia NLG11, respectively. CYP6AY1 increased by 20% under the action of Delftia and nicotine, while P450 enzyme activity increased by 18.1%. After CYP6AY1 interference, nicotine tolerance decreased, and the mortality rate reached 76.65% on the first day and 100% on the third day. Moreover, Delftia NLG11 helped axenic BPHs to increase their survival rate when fed nicotine in the liquid-diet sac (LDS) feeding system. Compared with axenic BPHs, the survival rate improved by 25.11% on day 2% and 6.67% on day 3. These results revealed an altered gut microbiota and a cooperative relationship between Delftia NLG11 and CYP6AY1 in nicotine-treated BPH, suggesting that insects can adapt to a hostile environment by interacting with their symbionts and providing a new idea for integrated pest management strategies.

Topics: Animals; Nicotine; Hemiptera; Insecticides; Microbiota; Cytochrome P-450 Enzyme System; Dolphins; Oryza

PubMed: 37634480
DOI: 10.1016/j.ecoenv.2023.115383

Authors: Md Rakib Hossain Raihan, Mira Rahman, Nur Uddin Mahmud...

We investigated the role of two different plant growth-promoting probiotic bacteria in conferring cadmium (Cd) tolerance in rapeseed ( cv. BARI Sarisha-14) through improving reactive oxygen species scavenging, antioxidant defense, and glyoxalase system. Soil, as well as seeds of rapeseed, were separately treated with probiotic bacteria, BRRh-4 and sp. BTL-M2. Fourteen-day-old seedlings were exposed to 0.25 and 0.5 mM CdCl for two weeks. Cadmium-treated plants resulted in a higher accumulation of hydrogen peroxide, increased lipid peroxidation, electrolyte leakage, chlorophyll damage, and impaired antioxidant defense and glyoxalase systems. Consequently, it reduced plant growth and biomass production, and yield parameters. However, probiotic bacteria-inoculated plants significantly ameliorated the Cd toxicity by enhancing the activities of antioxidant enzymes (ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase, glutathione reductase, glutathione peroxidase, and catalase) and glyoxalase enzymes (glyoxalase I and glyoxalase II) which led to the mitigation of oxidative damage indicated by reduced hydrogen peroxide, lipid peroxidation, and electrolyte leakage that ultimately improved growth, physiology, and yield of the bacterial inoculants rapeseed plants. When taken together, our results demonstrated the potential role of the plant probiotic bacteria, BRRh-4 and BTL-M2, in mitigating the Cd-induced damages in rapeseed plants.

PubMed: 36297762
DOI: 10.3390/plants11202738

Authors: Tsung-Lung Lu, Chienhsiu Huang

BACKGROUND

In recent years, has gained attention for its rare occurrence in patient infections. The literature consists mostly of case reports, necessitating further research to comprehensively understand risk factors, clinical characteristics, and management strategies.

METHODS

We conducted a retrospective cohort study involving patients diagnosed with infection at a tertiary teaching hospital between January 2014 and December 2022. The data included demographic details, comorbidities, bacterial cultures, antibiotic susceptibility, and treatment outcomes.

RESULTS

There were 26 patients diagnosed with infection who were predominantly older with multiple comorbidities. Approximately 76.9% of infection patients had polymicrobial infections. Twenty-one patients had received antibiotics within three months before they developed the infection, and these antibiotics were primarily third-generation cephalosporins, glycopeptides and fluoroquinolones. Antibiotic susceptibility testing showed resistance to aminoglycosides and susceptibility to imipenem, meropenem, ceftazidime, and piperacillin/tazobactam. Treatment outcome showed a mortality rate of 11.5%, mainly in patients with malignancy and advanced age.

CONCLUSION

infections predominantly affect older patients with multiple comorbidities. In terms of antibiotic therapy, carbapenems, cephalosporins, and piperacillin/tazobactam with antipseudomonal activity could all be considered.

PubMed: 38736436
DOI: 10.2147/IDR.S457781