Maltophilia Strain Research Articles

Exploring alkaline serine protease production and characterization in proteolytic bacteria Stenotrophomonas maltophilia: Insights from real-time PCR and fermentation techniques

This study focuses on identifying a potent microbe for efficient alkaline protease production, characterizing its properties, and investigating protease gene expression across diverse culture conditions. Stenotrophomonas maltophilia strain GEBN5 is methodically chosen and refined for peak alkaline protease production at 36 h (75.37 U/mL) in basal media employing precise adjustments in temperature, pH, incubation time, and carbon/nitrogen sources, achieving a noteworthy maximum protease activity of 97.03 U/mL in shake flask culture. Alkaline protease gene (StmPr1) up-regulation was explored via Real-time PCR under varied culture conditions (pH, temperature, carbon, and nitrogen sources) in a 2L fermenter at 150 rpm, resulting in peak protease production of 113 ± 0.53 U/mL in batch culture at pH 9.0, 35 °C, with sucrose and casein, respectively. The characterization data demonstrates exceptional stability of the current protease across a broad pH (9.0–11.0) and optimum temperature of 35 °C, highlighting its promising applications in diverse industrial and biotechnological settings. A higher instability complex of protein 28.59 was revealed by in silico analysis, indicating prolonged stability during hydrolysis and a wide range of potential uses. The purified protease demonstrates superior compatibility (45%–88% residual activity) with diverse detergent brands treated for 45 min at 40 °C, indicating its potential as a valuable additive for enhanced washing efficacy. Current research offers a novel strategy to boost protease production, presenting a promising alternative to chemical dehairing in leather industries and solid organic waste treatment. This approach holds the potential for mitigating environmental pollution through bioremediation.

Disease suppression, growth promotion and colonization attributes of resident endophytic bacteria against white root rot (Dematophora necatrix Hartig) of apple.

The inherent potential of apple plants was investigated to explore bacterial endophytes and their role in suppressing Dematophora necatrix,the causative pathogen of white root rot disease. Resultantly 34 endophytic bacteria isolated from healthy apple plants, and subsequently 6 most efficient isolates viz., Bacillus megaterium strain EA3, Enterobacter sp. strain EA7, Bacillus megaterium strain EK2, Stenotrophomonas maltophilia strain EK6, Acinetobacter nosocomialis strain ES2 and Pseudomonas aeruginosa strain ES8 depicting anti-pathogen interactions through preliminary screening were assessed further under in vitro, glasshouse and field conditions against white root rot pathogen/disease. Maximum mycelial growth inhibition (80.37%) was obtained with S. maltophilia strain EK6 encouraging for its seed treatment and soil application thereby providing significant effective control (87.91%) of white root rot under glasshouse conditions to other five bacterial endophytes evaluated simultaneously, followed by field efficacy of 83.70%. In addition, it has significantly enhanced the growth parameters of apple trees under both glasshouse and field conditions. The inoculated healthy plants were assessed for endophytic colonization which revealed maximum endosphere colonialism by S. maltophilia strain EK6. Additionally, confocal microscopic images of transverse sections of root cells colonized by bacterial endophytes as compared to untreated control implied their persistence and establishment in endosphere of apple seedlings. The study provides the first report on interaction between apple associated bacterial root endophytes and D. necatrix. The obtained endophytic strains could be employed as alternative for mitigating white root rot disease in future.

Prevalence and distribution of antibiotic-resistant bacteria in the rhizosphere and rhizoplane of Suaeda salsa and Sporobolus alterniflorus grown in a pristine environment

Antibiotic-resistant bacteria (ARB) are believed to have originated from pristine soil environments. However, the prevalence of ARB in the root-associated niches of plants grown in these environments, as well as the distribution patterns of ARB in the rhizosphere and rhizoplane—two critical root-associated niches—remains elusive. In this study, we investigated the prevalence and distribution of ARB in the rhizosphere and rhizoplane of two main plant species, Suaeda salsa and Sporobolus alterniflorus, grown in a pristine environment in Yancheng, China, to address these questions. In total,181 bacterial strains were isolated from the root-associated niches of the two plant species. Strong niche differentiation of the bacterial community between the rhizosphere and rhizoplane was identified by both bacterial isolation- and high-throughput 16S ribosomal RNA gene (rDNA) sequencing-based analyses. In total, 69.06 % of the isolated bacterial strains were classified as ARB, with strains resistant to β-lactam class antibiotics and polymyxin being predominant. The relative abundance of ARB in the rhizoplane was higher than that in the rhizosphere for both plant species. Furthermore, variations were noted in the prevalence and distribution of ARB in the root-associated niches between the two species. Several pathogenic ARBs, such as Stenotrophomonas maltophilia, were identified among the isolated strains. A representative S. maltophilia strain was sequenced, and several important antibiotic resistance- and pathogenicity-associated genes were identified in its genome. These findings provide novel insights into the prevalence and distribution patterns of ARB in the rhizosphere and rhizoplane of plants grown in pristine environments.

Optimization of laccase from Stenotrophomonas maltophilia E1 by submerge fermentation using coconut husk with its detoxification and biodecolorization ability of synthetic dyes

Enzymatic degradation of synthetic dyes holds an immense promise for addressing the environmental concerns associated with the textile and dye industries. This study aimed to isolate bacteria capable of producing laccase enzymes from an anthropogenic environment. Subsequently, viability of utilizing cost-effective agricultural residues as substrates for laccase production was assessed. Response Surface Methodology (RSM) and the One Variable at a Time (OVAT) approach was pursued for the optimization of laccase production, followed by pH and temperature stability, dye degradation and decolorization experiments, toxicological studies on the degraded dye metabolites. In results, laccase-producing bacterial strain was identified as Stenotrophomonas maltophilia strain E1 (S. maltophilia). Among variety of substrates, coconut husk exhibited optimal efficacy. In a statistical optimization study, it was found that S. maltophilia was capable of producing laccase 51.38 IU/mL, i.e., three times higher than the amount of laccase produced by unoptimized medium (16.7 IU/mL), and the enzyme activity was found to be steady at an acidic pH, and a mesophilic temperature range. The laccase obtained from S. maltophilia E1 demonstrated proficient dye decolorization capabilities, achieving a notable 92.1% reduction in Malachite green dye coloration at a concentration of 500 ppm. Gas chromatography–mass spectrometry (GC–MS) analysis of the decolorized derivatives of Malachite green revealed a conversion into a distinct compounds. Moreover, after undergoing laccase treatment, Malachite green exhibited decreased phytotoxic effects on Oryza sativa, pointing to enzymatic detoxification. Collectively, insights gained from the present study will contribute to the development of efficient enzymatic approaches for addressing the environmental pollution caused by synthetic dyes.Graphical

Taxonomic and Phylogenomic Assessment Identifies Phytopathogenicity Potential of Stenotrophomonas maltophilia Complex.

Stenotrophomonas maltophilia is a versatile bacterium found in plants, water, air, and even hospital settings. Deep taxono phylogenomics studies have revealed that S. maltophilia is a complex of several hidden species that are not differentiated using conventional approaches. In the last two decades, there have been increasing reports of S. maltophilia as a pathogen of diverse plants. Hence, proper taxonogenomic assessment of plant-pathogenic strains and species within the S. maltophilia complex (Smc) is required. In the present study, we formally propose a taxonomic amendment of Pseudomonas hibiscicola and P. beteli, reported as pathogens of Hibiscus rosa-sinensis and Betelvine (Piper betle) plants, respectively, as a misclassified member species of the Smc. Recently, a novel species of the genus, S. cyclobalanopsidis, was reported as a leaf spot pathogen of the oak tree genus Cyclobalanopsis. Interestingly, our investigation also revealed S. cyclobalanopsidis as another plant-pathogenic member species of the Smc lineage. In addition, we provide deep phylo-taxonogenomic evidence that S. maltophilia strain JZL8, reported as a plant pathogen, is a misclassified strain of S. geniculata, making it the fourth member species of the Smc harboring plant-pathogenic strains. Therefore, a proper taxonomic assessment of plant-pathogenic strains and species from the Smc is required for further systematic studies and management.

Soybean Bacterial Endophytes against Anthracnose Disease Collected from Karnataka State: An in-vitro Study

Endophytes trigger various defence mechanisms within their host plants, engaging primary and secondary protective pathways. This investigation primarily aimed to isolate bacterial endophytes from diverse agroecological regions in Karnataka. Subsequently, these endophytes were assessed for their inhibition against Colletotrichum truncatum using the in-vitro streak plate technique. A total of 43 bacteria isolated from soybean plants and key endophytes showing the inhibition against C. truncatum were in different zones namely, DHW-9(87%), BID-2(85%), BID-13(85%), BID-14(82.50%), DHW-15(80%), BID-15(75%),and BID-16(75%) exhibited notable efficacy against C. truncatum in decreasing order. Among these, the DHW-9 (Stenotrophomonas maltophilia strain P4-32) bacterial endophytes isolated from the North Transition Zone (Dharwad) were highly effective against the pathogen, possibly due to employing many direct and indirect mechanisms. Furthermore, the inhibition potential of the bacterial endophytes varies with and within the place of agroecological zones. In conclusion, it has been observed that the bacterial endophyte DHW-9 inhibited the progression of anthracnose disease caused by C. truncatum in controlled in vitro. Hence, it is imperative to conduct additional experiments, including pot and field studies, to explore its potential to enhance the growth and yield of soybean plants.

Engineering the Maize Root Microbiome: A Rapid MoClo Toolkit and Identification of Potential Bacterial Chassis for Studying Plant-Microbe Interactions.

Sustainably enhancing crop production is a global necessity to meet the escalating demand for staple crops while sustainably managing their associated carbon/nitrogen inputs. Leveraging plant-associated microbiomes is a promising avenue for addressing this demand. However, studying these communities and engineering them for sustainable enhancement of crop production have remained a challenge due to limited genetic tools and methods. In this work, we detail the development of the Maize Root Microbiome ToolKit (MRMTK), a rapid Modular Cloning (MoClo) toolkit that only takes 2.5 h to generate desired constructs (5400 potential plasmids) that replicate and express heterologous genes in Enterobacter ludwigii strain AA4 (Elu), Pseudomonas putida strain AA7 (Ppu), Herbaspirillum robiniae strain AA6 (Hro), Stenotrophomonas maltophilia strain AA1 (Sma), and Brucella pituitosa strain AA2 (Bpi), which comprise a model maize root synthetic community (SynCom). In addition to these genetic tools, we describe a highly efficient transformation protocol (107-109 transformants/μg of DNA) 1 for each of these strains. Utilizing this highly efficient transformation protocol, we identified endogenous Expression Sequences (ES; promoter and ribosomal binding sites) for each strain via genomic promoter trapping. Overall, MRMTK is a scalable and adaptable platform that expands the genetic engineering toolbox while providing a standardized, high-efficiency transformation method across a diverse group of root commensals. These results unlock the ability to elucidate and engineer plant-microbe interactions promoting plant growth for each of the 5 bacterial strains in this study.

Impact of Biogenic and Chemogenic Selenium Nanoparticles on Model Eukaryotic Lipid Membranes.

Microbial nanotechnology is an expanding research area devoted to producing biogenic metal and metalloid nanomaterials (NMs) using microorganisms. Often, biogenic NMs are explored as antimicrobial, anticancer, or antioxidant agents. Yet, most studies focus on their applications rather than the underlying mechanism of action or toxicity. Here, we evaluate the toxicity of our well-characterized biogenic selenium nanoparticles (bSeNPs) produced by the Stenotrophomonas maltophilia strain SeITE02 against the model yeast Saccharomyces cerevisiae comparing it with chemogenic SeNPs (cSeNPs). Knowing from previous studies that the biogenic extract contained bSeNPs in an organic material (OM) and supported here by Fourier transform infrared spectroscopy, we removed and incubated it with cSeNPs (cSeNPs_OM) to assess its influence on the toxicity of these formulations. Specifically, we focused on the first stages of the eukaryotic cell exposure to these samples─i.e., their interaction with the cell lipid membrane, which was mimicked by preparing vesicles from yeast polar lipid extract or phosphatidylcholine lipids. Fluidity changes derived from biogenic and chemogenic samples revealed that the bSeNP extract mediated the overall rigidification of lipid vesicles, while cSeNPs showed negligible effects. The OM and cSeNPs_OM induced similar modifications to the bSeNP extract, reiterating the need to consider the OM influence on the physical-chemical and biological properties of bSeNP extracts.

Jojan: a novel virus that lyses Stenotrophomonas maltophilia from dog.

Stenotrophomonas maltophilia is a Gram-negative bacterium widely distributed in the environment and associated with nosocomial infections, pneumonia, and bacteremia in humans and other mammals. We have isolated and sequenced a new virus that lyses the S. maltophilia strain from a dog skin. The virus has a siphovirus-like morphology and a linear dsDNA genome 60,804 pb in length with terminal repeats, four tRNA genes, and 111 putative proteins. The annotated genes resemble the corresponding genes of some siphoviruses, but the unique genome arrangement and limited similarity of the encoded proteins suggest that this virus does not belong to any known genus. The virus uses zinc metallopeptidase for lysis of its host. This enzyme is active in the presence of Zn2+ or Mg2+ ions and maintains its bactericidal activity up to 50°C. Both the virus itself and the endolysin specifically degrade only the host bacterial strain.

Biosynthesis and characterization of copper nanoparticles from Stenotrophomonas maltophilia and its effect on plant pathogens and pesticide degradation

Nanotechnology has gained popularity in recent years despite its early stage of development due to its capability of modulating metals into their Nano size, which leads to changes in the chemical, physical and optical properties of metals. Due to their distinctive characteristics, which make them useful in several domains of science and technology, the production of nanostructured materials, notably metallic nanoparticles, has attracted enormous interest over the past few decades. Strain SCS1.1 (Stenotrophomonas maltophilia) was chosen for the in vitro production of copper nanoparticles based on its greatest capacity to synthesize copper nanoparticles. Maximum copper nanoparticle synthesis was accomplished using 5.0% peptone, 4.0 mM copper sulfate, 3.0% beef extract, as well as 4.0% microbial inoculum size after 48 h of incubation at 30 °C and pH 8.0. Under ideal conditions, copper nanoparticles were produced in vitro through biosynthesis, and they were examined using TEM, SEM, FTIR, XRD, UV–visible spectroscopy, and DLS. The copper nanoparticles made from the S. maltophilia strain SCS1.1 were also tested for their ability to suppress several bacterial infections. The outcome demonstrates that the NPs were created and exhibited strong antibacterial, as well as antifungal activity and suspension and have the potential to break down these pesticides.

Characterization of blaAFM-1-positive carbapenem-resistant strains isolated in Guangzhou, China

BackgroundCarbapenemase-producing makes a great contribution to carbapenem resistance in Gram-negative bacilli. BlaAFM-1 gene was first discovered by us in Alcaligenes faecalis AN70 strain isolated in Guangzhou of China and, was submitted to NCBI on 16 November 2018.MethodsAntimicrobial susceptibility testing was performed by broth microdilution assay using BD Phoenix 100. The phylogenetic tree of AFM and other B1 metallo-β-lactamases was visualized by MEGA7.0. Whole-genome sequencing technology was used to sequence carbapenem-resistant strains including the blaAFM-1 gene. Cloning and expressing of blaAFM-1 were designed to verify the function of AFM-1 to hydrolyze carbapenems and common β-lactamase substrates. Carba NP and Etest experiments were conducted to evaluate the activity of carbapenemase. Homology modeling was applied to predict the spatial structure of AFM-1. A conjugation assay was performed to test the ability of horizontal transfer of AFM-1 enzyme. The genetic context of blaAFM-1 was performed by Blast alignment.ResultsAlcaligenes faecalis strain AN70, Comamonas testosteroni strain NFYY023, Bordetella trematum strain E202, and Stenotrophomonas maltophilia strain NCTC10498 were identified as carrying the blaAFM-1 gene. All of these four strains were carbapenem-resistant strains. Phylogenetic analysis revealed that AFM-1 shares little nucleotide and amino acid identity with other class B carbapenemases (the highest identity (86%) with NDM-1 at the amino acid sequence level). The spatial structure of the AFM-1 enzyme was predicted to be αβ/βα sandwich structure, with two zinc atoms at its active site structure. Cloning and expressing of blaAFM-1 verified AFM-1 could hydrolyze carbapenems and common β-lactamase substrates. Carba NP test presented that the AFM-1 enzyme possesses carbapenemase activity. The successful transfer of pAN70-1(plasmid of AN70) to E.coli J53 suggested that the blaAFM-1 gene could be disseminated by the plasmid. The genetic context of blaAFM indicated that the downstream of the blaAFM gene was always adjacent to trpF and bleMBL. Comparative genome analysis revealed that blaAFM appeared to have been mobilized by an ISCR27-related mediated event.ConclusionsThe blaAFM-1 gene is derived from chromosome and plasmid, and the blaAFM-1 gene derived from the pAN70-1 plasmid can transfer carbapenem resistance to susceptible strains through horizontal transfer. Several blaAFM-1-positive species have been isolated from feces in Guangzhou, China.

<i>Stenotrophomonas maltophilia</i> Infection in Trauma and Orthopedic Patients: Clinical Experience and Review

Background. Stenotrophomonas maltophilia (S. maltophilia) is a gram-negative non-fermenting bacillus and is a rare pathogen of orthopedic infection. Due to the relatively low virulence of S. maltophilia, many clinicians are still faced with the question of whether this bacterial species is simply a colonizing agent or the true cause of infection.
 Aim of the study to raise the awareness of practitioners about S. maltophilia as a rare pathogen of orthopedic infection.
 Methods. A retrospective analysis was performed concerning the frequency of S. maltophilia isolation from patients treated at the Vreden Center for periprosthetic infection and/or osteomyelitis from January 1, 2009 to October 31, 2022. The literature search by keywords was carried out in the PubMed/MEDLINE, Scopus, eLIBRARY, and Cyberleninka databases. The search retrieved 587 articles published in Russian or English over the period from 2012 to November 2022.
 Results. During the study period, 9 cases of orthopedic monoinfection with S. maltophilia were identified in 9 patients aged 36 to 83 years. At the time of admission, no leukocytosis was detected in patients, and only 2 of 9 patients had elevated C-reactive protein level. S. maltophilia is naturally resistant to many broad-spectrum antibiotics. Co-trimoxazole is considered the drug of choice for the treatment of S. maltophilia infection. The limited choice of drugs for targeted therapy, the presence of multiple determinants of antibiotic resistance, the existence of microbial associations and patient risks including implantation, chronic nature of infection, elderly age, as well as the presence of significant concomitant somatic pathology can lead to the ineffectiveness of the ongoing treatment of infections caused by S. maltophilia. Our experience shows that in the case of sensitivity of S. maltophilia strain to co-trimoxazole it is possible to prescribe this drug for a long course as monotherapy, provided that the radical surgical treatment of the focus is performed.

Potential application of a newly isolated phage BUCT609 infecting Stenotrophomonas maltophilia.

Stenotrophomonas maltophilia (S. maltophilia) is widely distributed in nature and frequently causes nosocomial infections. In this work, the biological characteristics and genome of a new S. maltophilia phage BUCT609 isolated from hospital sewage with S. maltophilia strain No. 3015 as host was analyzed and its therapeutic effect in vivo was explored. It was observed by TEM that phage BUCT609 belongs to the Podoviridae with a 10 nm tail structure and a capsid with a diameter of about 50 nm. It has a short latent period (about 10 min) and its burst size is 382 PFU /cell when multiplicity of infection (MOI) is 0.01. Furthermore, it has a high survival rate in the environment with a pH range from 3 to 10 and temperature range from 4°C to 55°C. The complete genome of phage BUCT609 is linear double-stranded DNA of 43,145 bp in length, and the GC content is 58%. The genome sequence of phage BUCT609 shares <45% homology with other phages. No virulence genes and antibiotic resistance genes were found in bacteriophage BUCT609. In vivo animal experiments showed that the survival rate of mice infected with S. maltophilia was significantly improved after the intranasal injection of phage BUCT609. Therefore, our study supports that phage BUCT609 could be used as a promising antimicrobial candidate for treating S. maltophilia infections.

Complete Genome Sequence of Stenotrophomonas maltophilia 1800, a New Bacterial Strain with Potential for Bioremediation of Oil-Contaminated Environments.

ABSTRACTStenotrophomonas maltophilia strain 1800 was isolated from the effluent of an industrial oil refinery in Algeria. Its genome was sequenced using Illumina MiSeq (2 × 150-bp read pairs) and Oxford Nanopore (long reads) technologies and assembled using Unicycler. It is composed of one chromosome of 4.83 Mb.

The potential of endophytic bacteria to suppress bacterial leaf blight in rice plants

Abstract. Rahma H, Nurbailis, Busniah M, Kristina N, Larasati Y. 2021. The potential of endophytic bacteria to suppress bacterial leaf blight in rice plants. Biodiversitas 23: 775-782. Endophytic bacteria are potential as biocontrol agents against bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. oryzae in rice to support sustainable agriculture. This study aimed to select and characterize 22 endophytic bacteria isolated from healthy rice, determine their ability to promote plant growth and suppress bacterial leaf blight disease in rice and also identify potential endophytic bacterial isolates. The study was arranged in a Completely Randomized Design with 24 treatments and three repetitions. The treatments used in the current study consisted of Xanthomonas oryzae infected plants and treated with endophytic bacterial isolates; infected plants without endophytic bacteria treatment (positive control), non-infected plants (negative control). Identification of potential endophytic bacteria was performed based on 16S rRNA sequences. Three out of 22 bacterial isolates, i.e., LmB1, LmA6, and LmB2 were able to suppress bacterial leaf blight disease with severity levels of 35.82%, 23.78%, and 23.78%, respectively. Based on the rice plant growth parameters, three bacterial isolates (LmA6, LmB1, and LmB35) were able to increase the growth of rice plants with an average value of 69.56%, 56.51%, and 47.82%, respectively. Two bacterial isolates, i.e., LmB 1 and LmA6 suppress the development of bacterial leaf blight disease and increase the growth of rice plants. Based on DNA sequence comparisons of DNA fragments amplified by 16S rRNA related marker of the selected bacterial isolates and database, then LmA6, LmB2, LmB1, and LmB35 had similarities with Bacillus cereus MD152 (96.87%), Bacillus thuringiensis ATCC 10792 (98.20%), Ochrobactrum intermedium strain OI1 (97.52%), and Stenotrophomonas maltophilia strain A1w2 (97.92%), respectively. Our study revealed that the indigenous endophytic bacteria from rice plants could be potential biological agents for controlling bacterial leaf blight disease and increasing plant growth.

Biodegradation of Synthetic Pyrethroid Insecticide Deltamethrin by Stenotrophomonas maltophilia Strain DRNB1

: Deltamethrin is one of the most used pyrethroid insecticide in different regions of the world. It is the fastacting insecticide that disrupts the cellular sodium channels. The deltamethrin residues are highly retained in environments, particularly in soil and water and have inevitable side effects on natural resources and human health. The most efficient, economical, and environmentally beneficial way of removing deltamethrin from contaminated sites is bioremediation. Bacteria are the most used biological agents in biodegradation studies. Thus, in this study deltamethrin-degrading bacteria Stenotrophomonas maltophilia strain DRNB1 was isolated and characterised. The bacterial growth was analysed by UV-spectrophotometer and deltamethrin degradation was studied by GC-MS analysis. S. maltophilia strain DRNB1 used deltamethrin as the sole carbon source for growth. Deltamethrin degradation efficiency of DRNB1 was 89.2% in insecticide supplemented media and 93% in presence of additional glucose in mineral media. These results implies that S. maltophilia strain DRNB1 could be used as a bioremediation technology for deltamethrin contaminated environments.

Subtractive genomics and molecular docking approach to identify drug targets against Stenotrophomonas maltophilia.

Stenotrophomonas maltophilia is a multidrug resistant pathogen associated with high mortality and morbidity in patients having compromised immunity. The efflux systems of S. maltophilia include SmeABC and SmeDEF proteins, which assist in acquisition of multiple-drug-resistance. In this study, proteome based mapping was utilized to find out the potential drug targets for S. maltophilia strain k279a. Various tools of computational biology were applied to remove the human-specific homologous and pathogen-specific paralogous sequences from the bacterial proteome. The CD-HIT analysis selected 4315 proteins from total proteome count of 4365 proteins. Geptop identified 407 essential proteins, while the BlastP revealed approximately 85 non-homologous proteins in the human genome. Moreover, metabolic pathway and subcellular location analysis were performed for essential bacterial genes, to describe their role in various cellular processes. Only two essential proteins (Acyl-[acyl-carrier-protein]—UDP-N acetyl glucosamine O-acyltransferase and D-alanine-D-alanine ligase) as candidate for potent targets were found in proteome of the pathogen, in order to design new drugs. An online tool, Swiss model was employed to model the 3D structures of both target proteins. A library of 5000 phytochemicals was docked against those proteins through the molecular operating environment (MOE). That resulted in to eight inhibitors for both proteins i.e. enterodiol, aloin, ononin and rhinacanthinF for the Acyl-[acyl-carrier-protein]—UDP-N acetyl glucosamine O-acyltransferase, and rhazin, alkannin beta, aloesin and ancistrocladine for the D-alanine-D-alanine ligase. Finally the ADMET was done through ADMETsar. This study supported the development of natural as well as cost-effective drugs against S. maltophilia. These inhibitors displayed the effective binding interactions and safe drug profiles. However, further in vivo and in vitro validation experiment might be performed to check their drug effectiveness, biocompatibility and their role as effective inhibitors.

Comparative Genomic Analysis of Stenotrophomonas maltophilia Strain W18 Reveals Its Adaptative Genomic Features for Degrading Polycyclic Aromatic Hydrocarbons.

ABSTRACTPolycyclic aromatic hydrocarbons (PAHs) are hazardous pollutants that are ubiquitous in the environment. Numerous bacteria have evolved to have degrading genes or pathways to degrade PAHs. Stenotrophomonas maltophilia strain W18 was found to be able to degrade PAHs. Including 43 other complete genome sequences of S. maltophilia strains, we performed a comparative genomic analysis of 44 S. maltophilia strains by running OrthoFinder. A KEGG pathway enrichment analysis of environmental and clinical isolates of S. maltophilia revealed that environmental isolates tended to enhance gene functions such as “energy metabolism,” “amino acid metabolism,” “xenobiotic biodegradation and metabolism,” and “folding, sorting, and degradation.” The pangenome of the 44 S. maltophilia strains was open, while the core genome was estimated to reach a steady plateau. Based on gene annotations, we inferred that most of the degradation potential came from the core genome of S. maltophilia, while character genes and accessory genes also contributed to the degradation ability of S. maltophilia W18. The genes expression level of core genes, character genes and accessory genes were proved by RT-qPCR experiment, and accessory genes encoding alcohol dehydrogenase were upregulated most compared with genes with similar functions. We performed a credible comparative genomic analysis of S. maltophilia strains. S. maltophilia W18 was set as a model PAH-degrading bacterium of this species in this study, which would provide guidance for understanding and predicting the degradation mechanisms of other PAH-degrading S. maltophilia strains lacking complete genome data or waiting to be determined.IMPORTANCE This study provided the latest comparative genomic analysis on Stenotrophomonas maltophilia strains and focused on analyzing their genomic features that allow them to adapt to natural environments. In this study, we set S. maltophilia W18 as a typical PAH-degrading strain of this species. By discussing the genomic adaptative features of degrading PAH, we can predict genomic adaptative features of other S. maltophilia PAH-degrading strains since the core function of this species is stable. The gene functions of how S. maltophilia environmental isolates are enhanced for adaptation to various natural environments compared with clinical isolates have been revealed. Combined with a pangenome analysis and RT-qPCR results, we have proved that core genes, character genes, and accessory genes are all involved in PAH degradation. Accessory genes encoding alcohol dehydrogenase were upregulated most compared with core and character genes with similar functions, which suggests that PAH metabolization potential might be enhanced by horizontal gene transfer.

Isolation, Characterization, and Genomic Investigation of a Phytopathogenic Strain of Stenotrophomonas maltophilia.

Stenotrophomonas maltophilia is ubiquitous in diverse environmental habitats. It merits significant concern because of its increasing incidence of nosocomial and community-acquired infection in immunocompromised patients and multiple drug resistance. It is rarely reported as a phytopathogen except in causing white stripe disease of rice in India and postharvest fruit rot of Lanzhou lily. For this study, Dickeya zeae and S. maltophilia strains were simultaneously isolated from soft rot leaves of Clivia miniata in Guangzhou, China, and were both demonstrated to be pathogenic to the host. Compared with the D. zeae strains, S. maltophilia strains propagated faster for greater growth in lysogeny broth medium and produced no cellulases or polygalacturonases, but did produce more proteases and fewer extracellular polysaccharides. Furthermore, S. maltophilia strains swam and swarmed dramatically less on semisolid media, but formed a great many more biofilms. Both D. zeae and S. maltophilia strains isolated from clivia caused rot symptoms on other monocot hosts, but not on dicots. Similar to previously reported S. maltophilia strains isolated from other sources, the strain JZL8 survived under many antibiotic stresses. The complete genome sequence of S. maltophilia strain JZL8 consists of a chromosome of 4,635,432 bp without a plasmid. Pan-genome analysis of JZL8 and 180 other S. maltophilia strains identified 50 genes that are unique to JZL8, seven of which implicate JZL8 as the potential pathogen contributor in plants. JZL8 also contains three copies of Type I Secretion System machinery; this is likely responsible for its greater production of proteases. Findings from this study extend our knowledge on the host range of S. maltophilia and provide insight into the phenotypic and genetic features underlying the plant pathogenicity of JZL8.

Draft Genome Sequence of the Multidrug-Resistant Strain Stenotrophomonas maltophilia N0320, Isolated from a Commercial Nanoparticle Product.

ABSTRACTStenotrophomonas maltophilia is an emerging opportunistic pathogen that is frequently associated with hospital infections. We report the 4.8-Mbp draft genome sequence of the oxidase-positive S. maltophilia strain N0320, an isolate from a commercial hydroxyapatite nanoparticle product.