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BMC Infectious Diseases Feb 2024Pseudomonas nitroreducens is a non-fermenting, gram-negative, rod-shaped bacterium commonly inhabiting soil, particularly soil contaminated with oil brine. To our...
BACKGROUND
Pseudomonas nitroreducens is a non-fermenting, gram-negative, rod-shaped bacterium commonly inhabiting soil, particularly soil contaminated with oil brine. To our knowledge, no cases of human infection with P. nitroreducens have been previously reported. Here, we present the first documented case of cholangitis caused by P. nitroreducens in a patient with bacteremia.
CASE PRESENTATION
A 46-year-old Japanese man with an advanced pancreatic neuroendocrine tumor was hospitalized with fever and chills. Four days before admission, the patient developed right upper abdominal pain. Two days later, he also experienced fever and chills. Endoscopic retrograde cholangiopancreatography was performed on the day of admission, and the patient was diagnosed as having cholangitis associated with stent dysfunction. Gram-negative rods were isolated from blood cultures, but attempts to identify the bacteria using VITEK2 and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with VITEK MS ver. 4.7.1 (bioMérieux Japan Co. Ltd., Tokyo, Japan) were unsuccessful. Finally, the organism was identified as P. nitroreducens using MALDI-TOF MS with a MALDI Biotyper (Bruker Daltonics Co., Ltd., Billerica, MA, USA) and 16 S ribosomal RNA sequencing. Despite thorough interviews with the patient, he denied any exposure to contaminated soil. The patient was treated with intravenous cefepime and oral ciprofloxacin for 16 days based on susceptibility results, achieving a good therapeutic outcome. At the outpatient follow-up on day 28, the patient was in good general condition.
CONCLUSIONS
This is the first reported human case of cholangitis with bloodstream infection caused by P. nitroreducens. This report provides clinicians with novel insights into the clinical manifestations and diagnostic methods necessary for the accurate diagnosis of P. nitroreducens, along with guidance on treatment.
Topics: Male; Humans; Middle Aged; Neuroendocrine Tumors; Bacteremia; Bacteria; Pseudomonas; Bacteria, Aerobic; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Cholangitis; Soil; Pancreatic Neoplasms
PubMed: 38336644
DOI: 10.1186/s12879-024-09092-8 -
International Journal of Systematic and... Jan 2024Five strains of two novel species were isolated from the wastewater treatment systems of a pharmaceutical factory located in Zhejiang province, PR China. Strains ZM22...
Five strains of two novel species were isolated from the wastewater treatment systems of a pharmaceutical factory located in Zhejiang province, PR China. Strains ZM22 and Y6 were identified as belonging to a potential novel species of the genus , whereas strains ZM23, ZM24 and ZM25 were identified as belonging to a novel species of the genus . These strains were characterized by polyphasic approaches including 16S rRNA gene analysis, multi-locus sequence analysis, average nucleotide identity (ANI), DNA-DNA hybridization (DDH), physiological and biochemical tests, as well as chemotaxonomic analysis. Genome-based phylogenetic analysis further confirmed that strains ZM22 and Y6 form a distinct clade closely related to ATCC 11996 and DSM 17888. Strains ZM23, ZM24 and ZM25 were grouped as a separate clade closely related to DSM 14399 and LAM1902. The orthoANI and DDH results indicated that strains ZM22 and Y6 belong to the same species. In addition, genomic DNA fingerprinting demonstrated that these strains do not originate from a single clone. The same results were observed for strains ZM23, ZM24 and ZM25. Strains ZM22 and Y6 were resistant to multiple antibiotics, whereas strains ZM23, ZM24 and ZM25 were able to degrade an emerging pollutant, triclosan. The phylogenetic, physiological and biochemical characteristics, as well as chemotaxonomy, allowed these strains to be distinguished from their genus, and we therefore propose the names sp. nov. (type strain ZM22=MCCC 1K08496=KCTC 82561) and sp. nov. (type strain ZM23=MCCC 1K08497=JCM 36056), respectively.
Topics: Bacterial Typing Techniques; Base Composition; Comamonas; DNA, Bacterial; Fatty Acids; Phylogeny; Pseudomonas; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Drug Industry; Water Purification
PubMed: 38190241
DOI: 10.1099/ijsem.0.006222 -
ISME Communications Sep 2023Food safety of leafy greens is an emerging public health issue as they can harbor opportunistic human pathogens (OHPs) and expose OHPs to consumers. Protists are an...
Food safety of leafy greens is an emerging public health issue as they can harbor opportunistic human pathogens (OHPs) and expose OHPs to consumers. Protists are an integral part of phyllosphere microbial ecosystems. However, our understanding of protist-pathogen associations in the phyllosphere and their consequences on public health remains poor. Here, we examined phyllosphere protists, human pathogen marker genes (HPMGs), and protist endosymbionts from four species of leafy greens from major supermarkets in Xiamen, China. Our results showed that Staphylococcus aureus and Klebsiella pneumoniae were the dominant human pathogens in the vegetable phyllosphere. The distribution of HPMGs and protistan communities differed between vegetable species, of which Chinese chive possessed the most diverse protists and highest abundance of HPMGs. HPMGs abundance positively correlated with the diversity and relative abundance of phagotrophic protists. Whole genome sequencing further uncovered that most isolated phyllosphere protists harbored multiple OHPs which carried antibiotic resistance genes, virulence factors, and metal resistance genes and had the potential to HGT. Colpoda were identified as key phagotrophic protists which positively linked to OHPs and carried diverse resistance and virulence potential endosymbiont OHPs including Pseudomonas nitroreducens, Achromobacter xylosoxidans, and Stenotrophomonas maltophilia. We highlight that phyllosphere protists contribute to the transmission of resistant OHPs through internalization and thus pose risks to the food safety of leafy greens and human health. Our study provides insights into the protist-OHP interactions in the phyllosphere, which will help in food safety surveillance and human health.
PubMed: 37660098
DOI: 10.1038/s43705-023-00302-z -
Heliyon Jun 2023Polystyrene is a plastic that leads to environmental pollution. In particular, expanded polystyrene is very light and takes up much space, causing additional...
OBJECTIVES
Polystyrene is a plastic that leads to environmental pollution. In particular, expanded polystyrene is very light and takes up much space, causing additional environmental problems. The aim of this study was to isolate new symbiotic bacteria which degraded polystyrene from mealworms.
METHODS
The population of polystyrene degrading bacteria was increased by enrichment culture of intestinal bacteria from mealworms with polystyrene as a sole carbon source. The degradation activity of isolated bacteria was evaluated by morphological change of micro-polystyrene particles and the surface change of polystyrene films.
RESULTS
Eight isolated species (, , , , , , , and ) were identified that degrade polystyrene.
CONCLUSION
Bacterial identification shows that a broad spectrum of bacteria decomposing polystyrene coexists in the intestinal tract of mealworms.
PubMed: 37426801
DOI: 10.1016/j.heliyon.2023.e17352 -
Journal of Hazardous Materials Sep 2023The presence of the sulfonic acid group in sulfonated anthraquinones (SAs) resulted in the difficulty in the mineralization of anthraquinone ring. Little information is...
The presence of the sulfonic acid group in sulfonated anthraquinones (SAs) resulted in the difficulty in the mineralization of anthraquinone ring. Little information is available on the removal pathway of the sulfonic acid group of SAs under aerobic/anaerobic conditions. Herein, sodium 1-aminoanthraquinone-2-sulfonate (ASA-2) was used as an important intermediate of SAs. A novel Pseudomonas nitroreducens WA capable of ASA-2 desulfonation was isolated from the Reactive Blue 19-degrading consortium WRB. Anaerobic desulfonation efficiency of 0.165 mM ASA-2 by strain WA reached 99% in 36 h at pH 7.5 and 35 ℃ using glucose as an electron donor. Further analysis showed that ASA-2 as an electron acceptor could be anaerobically transformed into 1-aminoanthraquinone and sulfite via the cleavage of C-S bond. Strain WA could also desulfonate sodium 1-amino-4-bromoanthraquinone-2-sulfonate and sodium anthraquinone-2-sulfonate. Under denitrification conditions, the formed sulfite could be oxidized to sulfate by nitrite via a chemical reaction, which was beneficial for nitrite removal. This phenomenon was observed in consortium WRB-amended system. Moreover, the consortium WRB could reduce the formed sulfite to sulfide due to the presence of Desulfovibrio. These results provide a theoretical basis for the anaerobic biodesulfonation of SAs along with nitrate removal and support for the development of sulfite-based biotechnology.
Topics: Nitrates; Sulfonic Acids; Nitrites; Anaerobiosis; Anthraquinones; Alkanesulfonates; Biotransformation; Sulfites; Denitrification
PubMed: 37348367
DOI: 10.1016/j.jhazmat.2023.131887 -
Journal of Environmental Science and... 2023Sheath blight () causes significant yield losses in rice ( L.). Its sustainable management needs an efficient biocontrol agent. The objective was to screen bacterial...
Sheath blight () causes significant yield losses in rice ( L.). Its sustainable management needs an efficient biocontrol agent. The objective was to screen bacterial isolates as an antagonist to and identify the most efficient ones as sheath blight suppressors under greenhouse conditions. Two assays (E1 and E2) were performed in a completely randomized design with three replications. E1 tested 21 bacterial isolates antagonists to . E2 was conducted under greenhouse conditions, with rice cultivar BRS Pampeira sown in plastic pots (7 kg) containing fertilized soil. Sixty old plants were inoculated with a segment of a toothpick containing fragments of , followed by spray inoculation of a bacterial suspension (10 CFU/mL). The severity of the disease was determined by calculating the relative lesion size formed on the colm. Isolates BRM32112 (), BRM65929 (), and BRM65919 () reduced colony radial growth by 92.8, 77.56, and 75.56%, respectively while BRM63523 (), BRM65923 and BRM65916 () and BRM65919 () with 23.45, 23.37, 23.62, and 20.17 cm, respectively were effective at suppressing sheath blight in greenhouse, indicating their potential as a biofungicide for sheath blight suppression.
Topics: Oryza; Plant Diseases; Rhizoctonia; Pest Control, Biological
PubMed: 37313602
DOI: 10.1080/03601234.2023.2220644 -
Frontiers in Microbiology 2023The root-knot nematodes (RKN), especially spp., are globally emerging harmful animals for many agricultural crops.
INTRODUCTION
The root-knot nematodes (RKN), especially spp., are globally emerging harmful animals for many agricultural crops.
METHODS
To explore microbial agents for biological control of these nematodes, the microbial communities of the rhizosphere soils and roots of sponge gourd () infected and non-infected by nematodes, were investigated using culture-dependent and -independent methods.
RESULTS
Thirty-two culturable bacterial and eight fungal species, along with 10,561 bacterial and 2,427 fungal operational taxonomic units (OTUs), were identified. Nine culturable bacterial species, 955 bacterial and 701 fungal OTUs were shared in both four groups. More culturable bacterial and fungal isolates were detected from the uninfected soils and roots than from the infected soils and roots (except no fungi detected from the uninfected roots), and among all samples, nine bacterial species ( sp., sp., , Enterobacteriaceae sp., , sp., Micrococcaceae sp., Rhizobiaceae sp., and sp.) were shared, with sp. and sp. being dominant. was exclusively present in the infested soils, while , , and sp., together with , sp., , and sp. were found only in the uninfected soils. , sp., , and sp. were only in the uninfected roots while sp. only in infected roots. After infestation, 319 bacterial OTUs (such as ) and 171 fungal OTUs (such as ) were increased in rhizosphere soils, while 181 bacterial OTUs (such as ) and 166 fungal OTUs (such as ) rose their abundance in plant roots. Meanwhile, much more decreased bacterial or fungal OTUs were identified from rhizosphere soils rather than from plant roots, exhibiting the protective effects of host plant on endophytes. Among the detected bacterial isolates, sp. TR27 was discovered to exhibit nematocidal activity, and , sp. P35, and to show repellent potentials for the second stage juveniles, which can be used to develop RKN bio-control agents.
DISCUSSION
These findings provided insights into the interactions among root-knot nematodes, host plants, and microorganisms, which will inspire explorations of novel nematicides.
PubMed: 37303801
DOI: 10.3389/fmicb.2023.1168179 -
Metabolic Engineering Jul 2023Focusing on the differences in the catalytic properties of two type I fatty acid synthases FasA and FasB, the fasA gene was disrupted in an oleic acid-producing...
Focusing on the differences in the catalytic properties of two type I fatty acid synthases FasA and FasB, the fasA gene was disrupted in an oleic acid-producing Corynebacterium glutamicum strain. The resulting oleic acid-requiring strain whose fatty acid synthesis depends only on FasB exhibited almost exclusive production (217 mg/L) of palmitic acid (C16:0) from 1% glucose under the conditions supplemented with the minimum concentration of sodium oleate for growth. Plasmid-mediated amplification of fasB led to a 1.47-fold increase in palmitic acid production (320 mg/L), while fasB disruption resulted in no fatty acid production, with excretion of malonic acid (30 mg/L). Next, aiming at conversion of the palmitic acid producer to a producer of palmitoleic acid (POA, C16:1Δ9), we introduced the Pseudomonas nitroreducens Δ9-desaturase genes desBC into the palmitic acid producer. Although this resulted in failure, we noticed the emergence of suppressor mutants that exhibited the oleic acid-non-requiring phenotype. Production experiments revealed that one such mutant M-1 undoubtedly produced POA (17 mg/L) together with palmitic acid (173 mg/L). Whole genomic analysis and subsequent genetic analysis identified the suppressor mutation of strain M-1 as a loss-of-function mutation for the DtxR protein, a global regulator of iron metabolism. Considering that DesBC are both iron-containing enzymes, we investigated the conditions for increased iron availability to improve the DesBC-dependent conversion ratio of palmitic acid to POA. Eventually, supplementation of both hemin and the iron chelator protocatechuic acid in the engineered strain dramatically enhanced POA production to 161 mg/L with a conversion ratio of 80.1%. Cellular fatty acid analysis revealed that the POA-producing cells were really equipped with unnatural membrane lipids comprised predominantly of palmitic acid (85.1% of total cellular fatty acids), followed by non-native POA (12.4%).
Topics: Palmitic Acid; Corynebacterium glutamicum; Metabolic Engineering; Fatty Acids; Iron
PubMed: 37286071
DOI: 10.1016/j.ymben.2023.06.002 -
Endocrine, Metabolic & Immune Disorders... 2023The host micronutrient milieu is a compilation of factors of both endogenous and exogenous origin. This milieu shapes the host's immune responses and can control the...
BACKGROUND AND AIMS
The host micronutrient milieu is a compilation of factors of both endogenous and exogenous origin. This milieu shapes the host's immune responses and can control the inflammatory response of the host when infected. Among vitamins, B12 plays a key role in the defense process because there is intense competition for it between pathogenic invaders and infected host cells. Alcoholic beverages and antibiotics can cause biological (in vivo) interferences that affect pathogenhost crosstalk. Ethanol is known to interfere with the absorption, distribution, and excretion of vitamin B12 in men and animals. However, the molecular mechanisms underlying this backdrop are not fully understood. Here, we explored how Gram-positive ethanol-producing and Gram-negative vitamin B12- producing microbes of the infected milieu interact to influence biomarkers of host cell defense responses in absorbing, digesting, and defensive cells.
MATERIAL AND METHODS
We investigated two different cell types of colon and liver origin, hepatic-like Huh7 cells and HT- 29/B6 colon cells. To assess the ability of secreted factors from bacteria to exert influence on co-cultured cell's secretion of host-defense markers in response to invading pathogens, cocultured human colonic HT-29/B6 and human hepatic Huh-7 (hereafter Huh7) cells were stimulated or not with Klebsiella pneumoniae 52145 for 24 h in the presence or absence of either Weissella confusa strain NRRL-B-14171 (as a Gram-positive producer of ethanol), Limosilactobacillus reuteri 20016 (as a Gram-positive producer of vitamin B12), or Pseudomonas nitroreducens 1650 (as a Gram-negative producer of vitamin B12). After stimulation, molecular functional biomarkers of host cell defense responses including total MMP-1, lysozyme activity, ALP, and IL-25 were measured.
RESULTS
While simultaneously reducing IL-25 secretion, Kp52145 alone significantly elicited MMP-1, lysozyme, and ALP secretion from co-cultured cells, as compared to no treatment. When compared with Kp 52145 stimulation alone, Pn1650 significantly potentiated MMP-1 and lysozyme secretions from Kp 52145-stimulated co-cultured cells by 29.7% and 67.4%, respectively. Simultaneously, a potentiated suppression (an overall decrease of 77.3%) in IL-25 secretion occurred 24 hours after Kn52145 plus Pn1650 administration. Compared to Kp52145-stimulation alone, treatment with W. confusa NRRL-B-14171 and Kp52145-stimulated co-cultured cells was associated with significant additive induction of MMP-1 and lysozyme secretions. However, compared to Kp52145-stimulation alone, W. confusa NRRL-B-14171 treatment significantly potentiated Kp52145-induced suppression of IL-25. Using the same condition as mentioned above and compared to Kp52145-stimulation alone, L. reuteri 20016 treatment altered the secretion pattern in response to Kp52145: L. reuteri 20016-treated cells displayed less aversive responses towards Kp52145, suggesting that L. reuteri 20016 modulation may act differently on Kp52145 - induced signaling.
CONCLUSION
Gram-negative and Gram-positive vitamin B12- producing bacteria differently affect the secretion of key immune biomarkers in co-cultured HT-29/B6 and Huh7 cells following exposure to Kp52145. Ethanol-producing bacteria additively potentiate pathogenicity and inflammatory responses upon infection. To confirm the biological consequences of these effects on human gut microbiota and health, further studies are warranted, incorporating ex vivo studies of human colon samples and host biomarkers such as cytohistological, molecular, or biochemical measurements.
Topics: Male; Animals; Humans; Ethanol; Matrix Metalloproteinase 1; Muramidase; Colon; Vitamin B 12
PubMed: 36998141
DOI: 10.2174/1871530323666230330111355 -
RdmA Is a Key Regulator in Autoinduction of DSF Quorum Quenching in Pseudomonas nitroreducens HS-18.MBio Feb 2023Diffusible signal factor (DSF) represents a family of widely conserved quorum-sensing (QS) signals which regulate virulence factor production and pathogenicity in...
Diffusible signal factor (DSF) represents a family of widely conserved quorum-sensing (QS) signals which regulate virulence factor production and pathogenicity in numerous Gram-negative bacterial pathogens. We recently reported the identification of a highly potent DSF-quenching bacterial isolate, Pseudomonas nitroreducens HS-18, which contains an operon with four DSF-inducible genes, , or , that are responsible for degradation of DSF signals. However, the regulatory mechanisms that govern the response to DSF induction have not yet been characterized. In this study, we identified a novel transcriptional regulator we designated RdmA (regulator of DSF metabolism) which negatively regulates the expression of and represses DSF degradation. In addition, we found that a gene cluster located adjacent to was also negatively regulated by RdmA and played a key role in DSF degradation; this cluster was hence named (DSF metabolism genes). An electrophoretic mobility shift assay and genetic analysis showed that RdmA represses the transcriptional expression of the genes in a direct manner. Further studies demonstrated that DSF acts as an antagonist and binds to RdmA, which abrogates RdmA binding to the target promoter and its suppression on transcriptional expression of the genes. Taken together, the results from this study have unveiled a central regulator and a gene cluster associated with the autoinduction of DSF degradation in HS-18, and this will aid in the understanding of the genetic basis and regulatory mechanisms that govern the quorum-quenching activity of this potent biocontrol agent. DSF family quorum-sensing (QS) signals play important roles in regulation of bacterial physiology and virulence in a wide range of plant and human bacterial pathogens. Quorum quenching (QQ), which acts by either degrading QS signals or blocking QS communication, has proven to be a potent disease control strategy, but QQ mechanisms that target DSF family signals and associated regulatory mechanisms remain largely unknown. Recently, we identified four autoinduced DSF degradation genes () in HS-18. By using a combination of transcriptome and genetic analysis, we identified a central regulator that plays a key role in autoinduction of expression, as well as a new gene cluster () involved in DSF degradation. The significance of our study is in unveiling the autoinduction mechanism that governs DSF signal quorum quenching for the first time, to our knowledge, and in identification of new genes and enzymes responsible for DSF degradation. The findings from this study shed new light on our understanding of the DSF metabolism pathway and the regulatory mechanisms that modulate DSF quorum quenching and will provide useful clues for design and development of a new generation of highly potent QQ biocontrol agents against DSF-mediated bacterial infections.
Topics: Humans; Quorum Sensing; Pseudomonas; Virulence; Virulence Factors; Bacterial Proteins
PubMed: 36537811
DOI: 10.1128/mbio.03010-22