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Prodigiosin, a valuable intracellular secondary metabolite, is produced by Serratia marcescens. However, synthesis during fermentation is constrained by osmotic pressure. In this study, adaptive laboratory evolution was applied to the strain SDSPY-136 to improve osmotic stress tolerance. After 120 passages, screening and validation yielded a strain with high osmotic pressure resistance, S. marcescens R82. The UV absorption spectrum, HPLC peak time, FTIR functional groups, and 1H NMR chemical shifts revealed that the pigment generated by the evolved strain was prodigiosin. After batch fermentation in a 5 L bioreactor, the prodigiosin concentration was 11.4 g/L, double the initial strain. Transcriptomic analyses revealed significant enrichment for 830 genes. R82 showed alterations in various pathways, indicating that the regulation of intracellular metabolic pathways promoted the availability of prodigiosin precursors, increasing the capacity for prodigiosin synthesis and extracellular release. This study clarifies the molecular evolution mechanism and presents a novel approach for improving yields in S. marcescens. [Display omitted] • Serratia marcescens was modified through adaptive laboratory evolution. • Pigment of the evolved R82 strain was characterized using spectroscopy. • Strain R82 was tolerant to osmotic pressure. • Batch fermentation yielded 11.4 g/L prodigiosin in 5 L bioreactors. • Transcriptome sequencing was used to analyze the evolutionary mechanism. [ABSTRACT FROM AUTHOR]

Background: Carbapenemase-producing Enterobacterales isolates are associated with significant mortality and have emerged as a major problem in healthcare settings worldwide. Objective: Our aim was to investigate the epidemiological and genotypic characteristics of carbapenemase-positive Enterobacterales isolates from patients hospitalised in three hospitals in the city of Batna, Algeria. Methods: Between 2016 and 2019, a total of 5,316 clinical isolates were obtained. The collected isolates were identified using the VITEK-2 system. Demographic and microbiological data were collected as well as the antimicrobial susceptibility testing, phenotypic and molecular characterisation of carbapenemase and mcr-1 genes were performed. Results: Out of the 5,316 isolates, 201 were carbapenem-resistant Enterobacterales isolates and 179 of them (89.05%) were positive for the production of carbapenemase, of which Klebsiella pneumoniae, Escherichia coli and Enterobacter cloacae were the most common. The blaOXA−48−like gene alone was detected in 147 isolates (82.12%) moreover, the blaNDM gene was detected in ten isolates (5.59%). Dual and triple combinations of carbapenemase genes were also observed here for the first time in Algeria: blaVIM and blaOXA−48−like; blaKPC, blaVIM and blaOXA−48−like; blaVIM and blaNDM; blaKPC, blaNDM and blaVIM; blaNDM and blaOXA−48−like genes. In addition, resistance to both colistin and carbapenem antibiotics was detected in eight isolates, however none of them was positive for the mcr-1 gene. Conclusion: This is the first study reporting the detection of carbapenemase genes in Klebsiella aerogenes, Enterobacter sakazakii, Raoultella ornithinolytica, Serratia ficaria, and Serratia marcescens and specific carbapenemase gene combinations in Algeria. The present study revealed that blaOXA−48−like were found to be the predominant carbapenemase genes in Batna hospitals. [ABSTRACT FROM AUTHOR]

The arid mountainous region of Hail in Saudi Arabia has a variety of desert vegetation, some of which are conventionally used in Bedouin traditional medicine. These plants need scientific examination. This research seeks to examine Blepharis ciliaris using a thorough multi-analytical methodology that includes antibacterial and antioxidant assessments as well as computational modeling. GC–MS analysis of the methanolic extract revealed 17 organic compounds, including pentadecanoic acid, ethyl methyl ester (2.63%); hexadecanoic acid, methyl ester (1.00%); 9,12-octadecadienoic acid (Z,Z)-, methyl ester (2.74%); 9-octadecenoic acid, methyl ester (E) (2.78%); octadecanoic acid (5.88%); 9-tetradecenoic acid (Z) (3.22%); and undec-10-enoic acid, undec-2-n-1-yl ester (5.67%). The DPPH test evaluated antioxidant activity, revealing a notable increase with higher concentrations of the methanolic extract, achieving maximum inhibition of 81.54% at 1000 µg/mL. The methanolic extract exhibited moderate antibacterial activity, with average inhibition zones of 10.33 ± 1.53 mm, 13.33 ± 1.53 mm, 10.67 ± 1.53 mm, and 10.00 ± 2.00 mm against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Serratia marcescens, respectively, as determined by the disk diffusion method. The minimum inhibitory concentration (MIC) values were 500 µg/mL for S. aureus and B. subtilis, whereas E. coli and S. marcescens showed susceptibility at 1000 µg/mL. Computational simulations were employed to assess the toxicity, drug-likeness, and ADMET profiles of compounds derived from Blepharis ciliaris. Thirteen bioactive compounds were assessed in silico against Staphylococcus aureus sortase A (PDB: 1T2O), Bacillus subtilis BsFabHb (PDB: 8VDB), Escherichia coli LPS assembly protein (LptD) (PDB: 4RHB), and a modeled Serratia marcescens outer-membrane protein TolC, focusing on cell wall and membrane structures. Compound 3, (+)-Ascorbic acid 2,6-dihexadecanoate, shown significant binding affinities to B. subtilis BsFabHb, E. coli LPS assembly protein, and S. marcescens TolC. [ABSTRACT FROM AUTHOR]

Serratia marcescens, isolated from the rhizosphere of rice crops, has the potential to improve the acquisition of scarce minerals and provide plant growth. Rice seeds microbiolized with S. marcescens and non-microbiolized seeds were sown in a culture medium enriched with non-labile phosphorus, and the roots were analyzed in WinRhizo. The plant segments were documented by scanning electron microscopy (SEM) and incubated in an NBRIP culture medium. DNAs from endophytic colonies were extracted and analyzed by PCR. The genome of S. marcescens was annotated using subsystem technology to detect genes involved in phosphorus solubilization, biofilm production, and growth promotion. The root system increased in area, volume, and length by 61.5, 31.5, and 101%, respectively. Halos were formed around segments of microbiolized plants, indicating the solubilization of non-labile phosphorus. SEM detected the presence of biofilms and microcolonies, identified as S. marcescens by the molecular markers. Genome annotation found genes with potential functions in plant growth promotion, including genes involved in the biosynthesis of indole-3-acetic acid, phosphate solubilization, and biofilm production. In the low phosphorus crop, the treated plants showed a 181% increase in total biomass. S. marcescens solubilizes non-labile phosphorus, colonizes endophytes, modifies the architecture of the root system, and promotes the growth of rice plants, and can be considered a biofertilizer for growing upland rice. [ABSTRACT FROM AUTHOR]

The ladybird beetle Micraspis discolor plays an important role as a predator of various arthropods within Asia's rice ecosystems. While pollen could serve as an alternative diet for this beetle, facilitating mass-rearing, its pollinivory might inadvertently result in attacks on crop pollen. This study aims to explore the role of gut bacteria on pollinivory of M. discolor. We found that antibiotic treatment significantly reduced the performance of M. discolor when fed Brassica campestris pollen. However, the treatment did not significantly affect their performance when fed an alternative diet of Ephestia kuehniella eggs. Further, we found that antibiotics can eliminate a strain of Serratia marcescens , SmMd, which is a specific gut bacterium in M. discolor. Moreover, the performance of M. discolor showed some degree of recovery when SmMd was reintroduced into its diet. Therefore, we propose that gut bacteria, particularly SmMd, play a significant role in pollen use by this ladybird beetle. This insight enhances our understanding of the important role of gut bacteria in insect adaptation to diverse diets and can potentially optimize the utilization of M. discolor in biological control strategies. [ABSTRACT FROM AUTHOR]

Simple Summary: Ants have evolved several defense mechanisms in response to the threat of pathogenic microorganisms. In this study, we detected two chemicals, 2,2′-methylenebis [6-(1,1-dimethylethyl)-4-methyl-phenol] (MP) and lup-20(29)-en-3-one (LP), from nest materials and evaluated their antimicrobial effects. The results showed that MP and LP significantly inhibited the growth of Beauveria bassiana through direct contact and fumigation but did not have any negative effect on Serratia marcescens growth. Subsequent analysis showed that MP was found in both the abdomen and the head of C. rogenhoferi workers and that LP is likely derived from the plant tissue of C. rogenhoferi nest materials. Our result showed that C. rogenhoferi capitalize on its own antimicrobial chemicals and probably the chemical defenses which have evolved in plants to protect itself against pathogens. Ants as social insects live in groups, which increases the risk of contagious diseases. In response to the threat of pathogens, ants have evolved a variety of defense mechanisms, including incorporating antimicrobial chemicals into nest material for nest hygiene. Crematogaster rogenhoferi is an arboreal ant, building its nest using plant tissues. It is still unclear how C. rogenhoferi is protected against pathogens in its nest. Two main chemicals, 2,2′-methylenebis[6-(1,1-dimethylethyl)-4-methyl-phenol] (MP) and lup-20(29)-en-3-one (LP), isolated from nest materials of C. rogenhoferi were used to investigate ants' anti-pathogenic activity against the entomopathogenic fungus Beauveria bassiana and the entomopathogenic bacteria Serratia marcescens. The results showed that MP and LP can inhibit the growth of B. bassiana through direct contact and fumigation. However, neither MP nor LP had any negative effect on S. marcescens growth. Subsequent analysis showed that MP was found in both the abdomen part and the head part of C. rogenhoferi workers, and LP was not detected in C. rogenhoferi workers. Since LP is a common plant secondary metabolite, it is implied that LP may originate from the plant tissue of C. rogenhoferi nest materials. Our results showed that C. rogenhoferi capitalizes on its own antimicrobial chemicals and probably the chemical defenses which have evolved in plants to protect itself against pathogens. [ABSTRACT FROM AUTHOR]

Cheese is a biologically active food product, characterised by its colour, texture, and taste. Due to its rich matrix of fats and proteins, as well as the fact that the cheese's surface acts as its own packaging, the cheese becomes more susceptible to contamination by microorganisms during the ripening process, particularly bacteria and fungi. The ripening of cheese involves several biochemical reactions, with the proteolytic activity of the cheese microbiota being particularly significant. Proteolysis results in the presence of free amino acids, which are precursors to various metabolic mechanisms that can cause discolouration (blue, pink, and brown) on the cheese rind. Surface defects in cheese have been documented in the literature for many years. Sporadic inconsistencies in cheese appearance can lead to product degradation and economic losses for producers. Over the past few decades, various defects have been reported in different types of cheese worldwide. This issue also presents opportunities for innovation and development in edible and bioactive coatings to prevent the appearance of colour defects. Therefore, this review provides a comprehensive analysis of cheese colour globally, identifying defects caused by microorganisms. It also explores strategies and innovation opportunities in the cheese industry to enhance the value of the final product. [ABSTRACT FROM AUTHOR]

Prodigiosin is a fascinating compound that has been gaining attention in the scientific community for its diverse range of potential applications. From its vibrant red color to its unique chemical properties, prodigiosin has captured the interest of researchers looking for innovative solutions in various fields. Prodigiosin, a red pigment produced by certain bacteria such as Serratia marcescens, has attracted interest from pharmaceutical researchers due to its promising potential in various therapeutic applications. A number of studies have demonstrated the potential of prodigiosin as an antimicrobial agent. With the rise of antibiotic resistance in the environment, prodigiosin is a promising solution to combat resistant strains and improve the effectiveness of existing antibiotic therapy. Moreover, different studies have shown that this natural pigment has anticancer properties by inhibiting the growth and proliferation of cancer cells. Prodigiosin exerts its anticancer effects by inducing apoptosis in cancer cells without causing significant damage to healthy cells. In this review, we will attempt to summarize the capabilities of prodigiosin and its prospects as a valuable tool in pharmaceutical research, and also review recent studies focusing on the various industries in which prodigiosin can be applied and the exciting possibilities it holds in the future. [ABSTRACT FROM AUTHOR]

Aluminum toxicity in acidic soils threatens rice (Oryza sativa L.) cultivation, hindering agricultural productivity. This study explores the potential of plant growth-promoting rhizobacteria (PGPR) as a novel and sustainable approach to mitigate aluminum stress in rice. Two rice varieties, INIAP-4M and SUPREMA I-1480, were selected for controlled laboratory experiments. Seedlings were exposed to varying aluminum concentrations (0, 2, 4, 8, and 16 mM) in the presence of four PGPR strains: Serratia marcescens (MO4), Enterobacter asburiae (MO5), Pseudomonas veronii (R4), and Pseudomonas protegens (CHAO). The INIAP-4M variety exhibited greater tolerance to aluminum than SUPREMA I-1480, maintaining 100% germination up to 4 mM and higher vigor index values. The study revealed that rhizobacteria exhibited different responses to aluminum concentrations. P. protegens and S. marcescens showed the highest viability at 0 mM (2.65 × 1010 and 1.71 × 1010 CFU mL−1, respectively). However, P. veronii and S. marcescens exhibited the highest viability at aluminum concentrations of 2 and 4 mM, indicating their superior tolerance and adaptability under moderate aluminum stress. At 16 mM, all strains experienced a decrease, with P. protegens and E. asburiae being the most sensitive. The application of a microbial consortium significantly enhanced plant growth, increasing plant height to 73.75 cm, root fresh weight to 2.50 g, and leaf fresh weight to 6 g compared to the control (42.75 cm, 0.88 g, and 3.63 g, respectively). These findings suggest that PGPR offer a promising and sustainable strategy to bolster rice resilience against aluminum stress and potentially improve crop productivity in heavy metal-contaminated soils. [ABSTRACT FROM AUTHOR]

Greater wax moth (GWM), Galleria mellonella (Lepidoptera: Pyralidae), is a destructive pest of honeybee hives. They lay eggs in the bee hives; and the hatched larvae feed on beeswax. The unique ability of GWM to digest the beeswax that contains ethene (CH2=CH2) bond has attracted attention because the same bond is also present in plastic polymers. Polymer-digesting ability, being a very uncommon among animals, we suspected a assistive role of gut bacteria of the insect in the process. The present study aimed to isolate and characterize potential polymer-degrading bacteria from GWM gut, following a culture-dependent approach, and to characterize them morphologically, biochemically, and with 16S rDNA sequences. We also intended to study polymer-degrading abilities of those bacteria, and check the presence of esterase, one of the most potent enzymes involved in plastic polymer degradation, using tributyrin agar test. We found nine bacterial isolates from GMW gut. Out of them, six showed positive results for plastic degradation to varying extents (19.3-31.2%), after 30 days of co-culture with plastic sheets. The esterase enzyme was found to be present in all of them in a qualitative test. Through 16S rDNA sequencing, four isolates were identified as gram-negative Serratia marcescens strains, one as gram-negative Ralstonia pickettii and one as gram-positive Bacillus cereus, some of which are known potential polymer degraders. Therefore, our hypothesis of involvement of gut bacteria in the digestion of polymers by Greater wax moth larvae was perhaps correct. There is possibility of exploiting the bacterial isolates for plastic-pollution remediation; after deeper and further experimentation. [ABSTRACT FROM AUTHOR]

Background and Aims: Pathogenic microbial infections are closely related to the development and prognosis of esophageal cancer. The distribution and resistance of pathogens in different diseases are regional and gradually change over time. This study aimed to determine the distribution and drug resistance of pathogens isolated from patients with esophageal cancer and provide a reference for the rational use of antibiotics. Methods: The results of strain identification and antimicrobial susceptibility testing of pathogens in patients with esophageal cancer from January 2013 to December 2022 at our hospital were retrospectively analyzed. SPSS Statistics 26.0 (IBM) and R software 4.3.1 were used for data analysis. Results: In total, 2322 non‐repetitive pathogens were isolated from 14,037 samples. Of all strains, 1713 (73.77%) were Gram‐negative bacteria, 483 (20.80%) were Gram‐positive bacteria, and 126 (5.43%) were fungi. The top 10 pathogens were Pseudomonas aeruginosa (19.81%), Stenotrophomonas maltophilia (12.88%), A. baumannii (9.91%), Klebsiella pneumoniae (9.82%), Staphylococcus aureus (7.54%), Candida albicans (3.92%), Staphylococcus epidermidis (3.19%), Escherichia coli (3.14%), Enterococcus faecalis (2.97%), and Serratia marcescens (2.15%). The isolation rate of S. maltophilia showed an upward trend (p < 0.05). The resistance rates of P. aeruginosa, S. maltophilia, A. baumannii, and Enterobacteriaceae bacteria to some common antibiotics showed a tendency to change (p < 0.05), and 2019 became a turning point to some extent. All common Gram‐positive pathogens were sensitive to vancomycin, except for three Enterococcus spp. isolates that showed intrinsic resistance. The prevalence of MRSA was 65.14% (114/175) in this study. In addition, the resistance rates of MRSA and MSSA to moxifloxacin, ciprofloxacin, levofloxacin, erythromycin, clindamycin, and penicillin were significantly different (p < 0.001). Conclusion: Pathogens are diverse in patients with esophageal cancer, with the most common being P. aeruginosa, followed by S. maltophilia. The pathogens exhibited different patterns of resistance. Antibiotics should be used rationally according to pathogen resistance patterns. [ABSTRACT FROM AUTHOR]

The growing emphasis on food safety and healthier lifestyles, driven by industrial expansion and scientific priorities, has highlighted the necessity of managing harmful microorganisms to guarantee food quality. A significant challenge in this domain is the control of pathogens that are capable of forming biofilms, entering a sessile state that enhances their resistance to broad-spectrum antibiotics. Essential oils, renowned for their antibacterial properties, present a promising natural alternative for food preservation. In this study, we analyzed the chemical composition of Santalum album essential oil (SAEO) using GC-MS, identifying (Z)-α-santalol (57.1%) as the primary constituent. Antimicrobial activity was confirmed through disc diffusion and minimum inhibitory concentration (MIC) assays against Gram-positive and Gram-negative bacteria and yeast from the genus Candida. Additionally, in situ experiments demonstrated that vapor-phase SAEO effectively inhibited Serratia marcescens on the food model, supporting its potential as a natural preservative. MBIC assays, crystal violet staining, and MALDI-TOF MS analysis on S. enterica biofilms were used to further evaluate the antibiofilm effects of SAEO. The crystal violet assay revealed a strong antibiofilm effect, while the MALDI-TOF MS analysis showed changes in the bacterial protein profiles on both glass and plastic surfaces. SAEO also showed significant anti-Salmonella activity on vacuum-packed carrot slices. SAEO outperformed the control samples. The insecticidal activity against Megabruchidius dorsalis was also studied in this work, and the best insecticidal activity was found at the highest concentrations. These findings indicate that SAEO could serve as a valuable component in food preservation, with notable antibacterial and antibiofilm benefits. [ABSTRACT FROM AUTHOR]

Plant growth–promoting bacteria (PGPB) can play an essential role as biofertilizers to increase pasture efficiency and reduce the application of agrochemicals. Plant growth can be potentialized when these bacteria are combined with silica nanoparticles (SiNPs). The present study aimed to evaluate the effect of PGPB associated with SiNPs on the growth of bahiagrass (Paspalum notatum) seedlings. The PGPB were isolated from rhizospheric soils and leaves of Paspalum spp. grown in the tropical high‐altitude region of Brazil and selected by their ability to fix nitrogen, solubilize phosphate, and synthesize indoleacetic acid (IAA). They were identified as Alcaligenes faecalis, Enterobacter asburiae, and Serratia marcescens by 16S rDNA sequencing. Spherical SiNPs (85 nm in diameter) were synthesized by the hydrolysis of the silicon precursor tetraethyl orthosilicate (TEOS), characterized by infrared spectroscopy and scanning electron microscopy (SEM) and applied at 5% (0.05 mg·mL−1) and 10% (0.1 mg·mL−1) concentrations. Disinfected P. notatum seeds were treated with PGPB, SiNPs, and PGPB + SiNPs and cultivated in magenta boxes containing peat, sand, and perlite. The seedlings were evaluated for their germination percentage, root length, shoot length, root dry weight, and shoot dry weight. Disinfected seeds subjected to the same treatments were also grown in Petri dishes containing 0.7% agarose. The roots of the seedlings in Petri dishes were stained with diaminobenzidine tetrahydrochloride (DAB) and visualized using a light microscope to confirm bacterial colonization. The three strains without SiNPs promoted the growth of P. notatum seedlings. S. marcescens treatment presented the greatest shoot length, and both concentrations of nanosilica with PGPB improved or maintained root lengths. Treatments of S. marcescens and E. asburiae with 10% SiNPs showed 100% seed germination. Seedlings inoculated with 10% SiNPs with S. marcescens and E. asburiae alone showed the highest shoot dry weight, and all treatments increased root dry weight compared to the control. The 10% SiNPs' concentration inoculated with S. marcescens and A. faecalis positively affected P. notatum seedlings' growth. This study suggests that nanosilica can be applied with PGPB to improve the development of bahiagrass and reduce the need for applications of agrochemicals. [ABSTRACT FROM AUTHOR]

Background: Microbial prodigiosin pigment has been proposed as a promising biomolecule having an antibacterial, immunosuppressive, antimalarial, antineoplastic, and anticancer activities. The good outcome originates from getting natural pigment, which has many medical applications. Results: In this investigation, prodigiosin (PG) was extracted, characterized by UV-visible spectroscopy, thin-layer chromatography, mass spectroscopy, Fourier-transform infrared spectroscopy, and tested in various medical applications as an antibacterial, antioxidant, antibiofilm, anticancer, and wound healing agent at different concentrations. Antibacterial activity of PG pigment was shown against both Gram-positive and Gram-negative bacterial strains. Enterococcus faecalis was the most severely impacted, with minimum inhibitory value of 3.9 µg/mL. The formed biofilm by Pseudomonas aeruginosa was suppressed by 58–2.50% at prodigiosin doses ranging from 1000 to 31.25 µg/mL, respectively. The half-maximal inhibitory concentration (IC50) of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical was 74.18 ± 23.77 µg/mL. At 100 µg/mL concentration, OK482790 prodigiosin had no harmful effect on normal skin cells and exhibited mild wound healing properties. Additionally, molecular docking simulations confirmed the prodigiosin's interactions with target proteins, including epidermal growth factor receptor tyrosine kinase (EGFR-TK, PDB ID: 1M17), peptide deformylase from E. faecalis (PDB ID: 2OS1), acidic fibroblast growth factor (FGF-1, PDB ID: 3K1X), PA14_16140 protein from P. aeruginosa (PDB ID: 8Q8O), and human peroxiredoxin 5 (PDB ID: 1HD2) for explaining the anticancer, antibacterial, wound healing, antibiofilm, and antioxidant activities, respectively. Prodigiosin had favorable binding affinities and putative modes of action across various therapeutic domains. Conclusion: This study pioneers the use of prodigiosin as a natural alternative to synthetic medicine since it fights germs, heals wounds, is antioxidant, and reduces biofilm formation. Clinical trial number: Not applicable. [ABSTRACT FROM AUTHOR]

Background: Odontotermes formosanus (Shiraki) is a highly damaging agroforestry pest. Serratia marcescens is a broad-spectrum insecticidal pathogen and is highly lethal to O. formosanus. However, little is known about the mechanism between them. To improve the biological control of pests, a more in-depth analysis of the interactions between the pests and the pathogens is essential. Results: We used RNA-seq, enzyme activity assays and real-time fluorescent quantitative PCR (qPCR) to explore the defense responses of O. formosanus against SM1. RNA-seq results showed that 1,160, 2,531 and 4,536 genes were differentially expressed at 3, 6 and 12 h after SM1 infection, and Kyoto Encyclopedia of Genes and Genomes (KEGG) results indicated that immune response and energy metabolism were involved in the defense of O. formosanus against SM1. Reactive oxygen species (ROS) levels and ROS synthesis genes were significantly elevated, and the antioxidant system were induced in O. formosanus after SM1 infection. In addition, the cellular immune genes were affected, and the Toll, immune deficiency (Imd), Janus kinase/signal transducer and activator of transcription (JAK/STAT), c-Jun N-terminal Kinase (JNK) and melanization pathways were activated. In vitro, Oftermicin, an antimicrobial peptide, had a significantly inhibitory effect on SM1. Furthermore, the expression levels and enzyme activities of phosphofructokinase (PFK), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and isocitrate dehydrogenase (IDH) in glycolysis and tricarboxylic acid (TCA) cycles were increased. Conclusions: Our results clearly demonstrated that O. formosanus defended against SM1 by activating the antioxidant system, innate immunity and energy metabolism. This study would provide useful information for the development of biological controls of O. formosanus. [ABSTRACT FROM AUTHOR]

Aim: This study aims to evaluate the impact of seed primimg with soil microorganism on the germination and metabolism of pearl millet seeds when exposed to the allelopathic effects of some specific weed extracts. Methods: Pearl millet seeds were categorized into five distinct groups. Four of these groups were subjected to priming with different soil microorganisms: Bacillus velezensis, Pseudomonas fluorescens, Serratia marcescens, and Trichoderma viride. The remaining, fifth group underwent hydropriming. Subsequently, these groups were subjected to germination in the presence of weed extracts, a process that extended over five days. Following germination, various factors were assessed, including germination percentage, radicle and plumule length, and seed vigor. Furthermore, the study encompassed the analysis of biochemical parameters such carbohydrate and phytate hydrolysis, oxidative stress markers, antioxidant enzyme activity, and secondary metabolite. Results: The findings of the study revealed that biopriming of pearl millet seeds with soil microorganisms led to a significant enhancement in germination, even when exposed to different weed extract treatments. This improvement was chiefly manifested through heightened levels of antioxidant enzymes, which mitigate the oxidative stress induced by the weed treatments. Moreover, the biopriming process improved the hydrolysis in germinated seeds, resulting in energy savings and a reduction in carbon utilization for secondary metabolism through the shikimic acid pathway and the phenylpropanol pathway. This facilitated the production of defense molecules like phenols and flavonoids. Conclusion: Seed priming with soil microorganism ultimately bolsters the seeds' tolerance against allelochemicals originating from weed residue treatments. [ABSTRACT FROM AUTHOR]

Determining the effects of fermentation duration on the microbial ecosystem, potential pathogenic risks, and metabolite generation during the fermentation of distilled grains is essential for safeguarding the safety and enhancing the nutritional profile of animal feed. This study investigates the effect of varying fermentation times (9, 30, and 60 days) on microbial diversity, pathogenic risk, and metabolite profiles in distiller grains using 16S rDNA sequencing and LC–MS-based metabolomics. The results showed that early fermentation (9–30 days) enhanced the abundance of beneficial bacteria, such as Lactobacillus reuteri and Lactobacillus pontis (p < 0.05), while pathogenic bacteria, like Serratia marcescens and Citrobacter freundii, were significantly reduced (p < 0.05). Metabolomic analysis revealed an increase in unsaturated fatty acids and the degradation of biogenic amines during early fermentation. However, prolonged fermentation (60 days) led to a resurgence of pathogenic bacteria and reduced the synthesis of essential metabolites. These findings suggest that fermentation duration must be optimized to balance microbial safety and nutrient quality, with 30 days being the optimal period to reduce pathogenic risks and enhance feed quality. [ABSTRACT FROM AUTHOR]

Prodigiosin finds tremendous application in the food industry owing to its physicochemical and non-toxic attributes. In the present investigation, microbial production of food color (prodigiosin) was done by Serratia marcescens NCIM 5246 under solid-state fermentation (SSF). For economical prodigiosin yield, initial substrate screening was conducted using agro-waste such as rice bran, wheat bran, orange peel powder, green gram husk and cane molasses. A maximum pigment yield of 1059.67 ± 1.53 µg/L was observed on wheat bran media. Further, Taguchi Design of the experiment (DOE) using Qualitek-4 software with bigger is better as quality attributes was done for process optimization. The Taguchi (DOE) comprised five independent variables, i.e., pH, temperature, substrate concentration, trace metal concentration, and inoculum size at two levels. The software deduced independent variables' individual and interactive effects on product yield by performing an L8 orthogonal array (OA). The output variable (prodigiosin yield) was improved based on the S/N ratio. Under optimized cultural conditions maximum prodigiosin yield of 1320.2 ± 20 µg/L was obtained. The expected prodigiosin yield of 1386.60 µg/L showed a 95% resemblance with the actual yield, showed model validation, and 24.57% improvement in overall yield. The extracted pigment was purified by TLC and was characterized as prodigiosin by absorption spectroscopy and FTIR. [ABSTRACT FROM AUTHOR]

BACKGROUND: Electrochemically active bacteria (EAB) capable of bidirectional extracellular electron transfer (EET), either outward or inward EET, largely control the efficiency of interactions and electrical communication between biofilm and electrode and, thus, control the performance of bioelectrochemical systems (BESs) for heavy metals removal. However, the behavior of such metallurgical EAB capable of bidirectional EET has yet to be investigated, and the role of extracellular polymeric substances (EPS) in these switchable EAB with bidirectional EET and in the presence of heavy metals remains unexplored in the single‐chamber BESs treating heavy metal‐based wastewaters that are limited by carbon/electron sources or electron acceptors. RESULTS: The biofilms of the Cr(VI)‐tolerant EAB Stenotrophomonas sp. YS1 and Serratia marcescens Q1 exhibited bidirectional EET metabolizing either organic (acetate) or inorganic (HCO3−) species with simultaneous removal of Cr(VI) in single‐chamber BESs. Q1 inward EET uptake of electrons was more efficient than that of YS1 (165 μA vs. 118 μA); meanwhile, YS1 outward EET was more efficient than Q1 (8.0 μA vs. 4.7–5.2 μA). The adaptive electrochemically‐tunable EPS in both biofilm strains was regulated by the direction of the EET (inward or outward) in the presence of Cr(VI) and circuital current. CONCLUSION: This study demonstrates the switching properties of EAB, such as Stenotrophomonas sp. or S. marcescens, that are capable of bidirectional EET to or from the electrodes, and it displays the regulation of such responses with the amount and compositional diversity of the biofilms' EPS, giving a comprehensive appreciation of tunable EPS for Cr(VI)‐wastewater treatment in single‐chamber BESs. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Abstract Background Odontotermes formosanus (Shiraki) is a highly damaging agroforestry pest. Serratia marcescens is a broad-spectrum insecticidal pathogen and is highly lethal to O. formosanus. However, little is known about the mechanism between them. To improve the biological control of pests, a more in-depth analysis of the interactions between the pests and the pathogens is essential. Results We used RNA-seq, enzyme activity assays and real-time fluorescent quantitative PCR (qPCR) to explore the defense responses of O. formosanus against SM1. RNA-seq results showed that 1,160, 2,531 and 4,536 genes were differentially expressed at 3, 6 and 12 h after SM1 infection, and Kyoto Encyclopedia of Genes and Genomes (KEGG) results indicated that immune response and energy metabolism were involved in the defense of O. formosanus against SM1. Reactive oxygen species (ROS) levels and ROS synthesis genes were significantly elevated, and the antioxidant system were induced in O. formosanus after SM1 infection. In addition, the cellular immune genes were affected, and the Toll, immune deficiency (Imd), Janus kinase/signal transducer and activator of transcription (JAK/STAT), c-Jun N-terminal Kinase (JNK) and melanization pathways were activated. In vitro, Oftermicin, an antimicrobial peptide, had a significantly inhibitory effect on SM1. Furthermore, the expression levels and enzyme activities of phosphofructokinase (PFK), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and isocitrate dehydrogenase (IDH) in glycolysis and tricarboxylic acid (TCA) cycles were increased. Conclusions Our results clearly demonstrated that O. formosanus defended against SM1 by activating the antioxidant system, innate immunity and energy metabolism. This study would provide useful information for the development of biological controls of O. formosanus.

Abstract Quorum sensing (QS) inhibition has emerged as a promising target for directed drug design, providing an appealing strategy for developing antimicrobials, particularly against infections caused by drug‐resistant pathogens. In this study, we designed and synthesized a total of 33 β‐nitrostyrene derivatives using 1‐nitro‐2‐phenylethane (NPe) as the lead compound, to target the facultative anaerobic bacterial pathogen Serratia marcescens. The QS‐inhibitory effects of these compounds were evaluated using S. marcescens NJ01 and the reporter strain Chromobacterium violaceum CV026. Among the 33 new β‐nitrostyrene derivatives, (E)‐1‐methyl‐4‐(2‐nitrovinyl)benzene (m‐NPe, compound 28) was proven to be a potent inhibitor that reduced biofilm formation of S. marcescens NJ01 by 79%. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) results revealed that treatment with m‐NPe (50 μg/ml) not only enhanced the susceptibility of the formed biofilms but also disrupted the architecture of biofilms by 84%. m‐NPe (50 μg/ml) decreased virulence factors in S. marcescens NJ01, reducing the activity of protease, prodigiosin, and extracellular polysaccharide (EPS) by 36%, 72%, and 52%, respectively. In S. marcescens 4547, the activities of hemolysin and EPS were reduced by 28% and 40%, respectively, outperforming the positive control, vanillic acid (VAN). The study also found that the expression levels of QS‐ and biofilm‐related genes (flhD, fimA, fimC, sodB, bsmB, pigA, pigC, and shlA) were downregulated by 1.21‐ to 2.32‐fold. Molecular dynamics analysis showed that m‐NPe could bind stably to SmaR, RhlI, RhlR, LasR, and CviR proteins in a 0.1 M sodium chloride solution. Importantly, a microscale thermophoresis (MST) test revealed that SmaR could be a target protein for the screening of a quorum sensing inhibitor (QSI) against S. marcescens. Overall, this study highlights the efficacy of m‐NPe in suppressing the virulence factors of S. marcescens, identifying it as a new potential QSI and antibiofilm agent capable of restoring or improving antimicrobial drug sensitivity.

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This experiment was conducted to use microorganisms from rapeseed meal and rape field soil as a source, through the transparent hydrolysis circle method and solid-state fermentation of rapeseed meal, with the aim of screening strains that degraded the glucosinolate and increased the tannin content in rapeseed meal. Microorganisms in rapeseed meal and rape field soil were isolated, purified and cultured by using basic medium; primary screening was carried out by the transparent hydrolysis circle method using the glucosinolate and tannin screening medium; subsequently, the solid-state fermentation technology of rapeseed meal was used to screen strains that could both degrade the glucosinolate and increase the tannin content of rapeseed meal, using the glucosinolate and tannin content of rapeseed meal as the screening indexes. The results showed as follows: ① the 13 strains were obtained by primary screening. ② The solid-state fermentation technology of rapeseed meal was used to screen and obtain the strain X78 that could both degrade the glucosinolate and increase the tannin content of rapeseed meal, with the glucosinolate degradation rate of 7.31%, and the tannin growth rate of 9.89%. ③ The strain X78 is identified as Serratia marcescens by morphological characterization, biochemical identification and 16S rDNA sequence analysis. It is concluded that using microorganisms from rapeseed meal and rape field soil as a source, it is possible to screen for strains that degrading glucosinolate as well as increasing tannin content in rapeseed meal. [ABSTRACT FROM AUTHOR]

In the real world, active agents interact with surrounding passive objects, thus introducing additional degrees of complexity. The relative contributions of far-field hydrodynamic and near-field contact interactions to the anomalous diffusion of passive particles in suspensions of active swimmers remain a subject of ongoing debate. We constructed a quasi-two-dimensional microswimmer–colloid mixed system by taking advantage of Serratia marcescens' tendency to become trapped at the air–water interface to investigate the origins of the enhanced diffusion and non-Gaussianity of the displacement distributions of passive colloidal tracers. Our findings reveal that the diffusion behavior of colloidal particles exhibits a strong dependence on bacterial density. At moderate densities, the collective dynamics of bacteria dominate the diffusion of tracer particles. In dilute bacterial suspensions, although there are multiple dynamic types present, near-field contact interactions such as collisions play a major role in the enhancement of colloidal transport and the emergence of non-Gaussian displacement distributions characterized by heavy exponential tails in short times. Despite the distinct types of microorganisms and their diverse self-propulsion mechanisms, a generality in the diffusion behavior of passive colloids and their underlying dynamics is observed. [ABSTRACT FROM AUTHOR]

Introduction: The Seraph® 100 Microbind® Affinity Filter is a biomimetic adsorbent device that can remove pathogens from the blood. Case Presentation: Here, we report the successful use of the Seraph® 100 to treat both a SARS-CoV-2 reinfection leading to severe COVID-19 pneumonia as well as subsequent secondary lung infections including Acinetobacter baumannii, Serratia marcescens, and Pseudomonas aeruginosa multidrug-resistant bacteria. To our knowledge, this 46-year-old black male is the first patient in which four treatments with this pathogen adsorber, one for a viral and three for different bacterial infections, have been successfully used. Conclusion: The Seraph® 100 can be easily and successfully used in conjunction with standard (anti-infective) treatment. [ABSTRACT FROM AUTHOR]

Background: Dengue is the most re-emergent infection, with approximately 100 million new cases reported annually, yet no effective treatment or vaccine exists. Here, we aim to define the microbial community structure and their functional profiles in the dengue positive patients with varying disease severity. Methodology/Principal findings: Hospital admitted 112 dengue-positive patients blood samples were analyzed by dual RNA-sequencing to simultaneously identify the transcriptionally active microbes (TAMs), their expressed genes and associated pathways. Results highlight that patients with severe dengue exhibited increased microbial diversity and presence of opportunistic species (unique and core) which includes Bacillus cereus, Burkholderia pseudomallei, Streptococcus suis, and Serratia marcescens. The functional profile analysis revealed enriched metabolic pathways such as protein degradation, nucleotide biosynthesis, ion transport, cell shape integrity, and ATP formation in severe cases, indicating the high energy demands and adaptability of these microbes. Conclusion: Our metatranscriptomic approach provides a species-level characterization of blood microbiome composition and reveals a heightened diversity of TAMs in patients with severe dengue, underscoring the need for further research into the role of blood microbiota in disease progression. Comparing the microbial signatures across the severity classes early in the disease offers unique potential for convenient and early diagnosis of dengue infection. Author summary: Dengue poses a significant public health challenge in tropical and subtropical regions. The lack of a specific treatment or broadly effective vaccine highlights the critical need for novel approaches. In this study, we investigated the transcriptionally active microbial species (TAMs) in 112 dengue-positive patients from MAX Hospital in Delhi, India, to identify their correlations with disease severity. RNA-seq analysis revealed an increased abundance of opportunistic TAMs in severe dengue patients, with some species showing significant associations with platelet counts and total leukocyte count (TLC). Our findings underscore the underappreciated importance of the blood microbiome in dengue, particularly the heightened metabolic activity of these opportunistic species in severe cases. This study offers valuable insights for early infection diagnosis for dengue management. The species-level data identified here could pave the way for systematic exploration of microbial involvement in dengue virus (DENV) infections, potentially serving as an indicator for new adjuvant treatment strategies. [ABSTRACT FROM AUTHOR]

Mutualistic relationships with photosynthetic organisms are common in cnidarians, which form an intracellular symbiosis with dinoflagellates in the family Symbiodiniaceae. The establishment and maintenance of these symbionts are associated with the suppression of key host immune factors. Because of this, there are potential trade-offs between the nutrition that cnidarian hosts gain from their symbionts and their ability to successfully defend themselves from pathogens. To investigate these potential trade-offs, we utilized the facultatively symbiotic polyps of the upside-down jellyfish Cassiopea xamachana and exposed aposymbiotic and symbiotic polyps to the pathogen Serratia marcescens. Symbiotic polyps had a lower probability of survival following S. marcescens exposure. Gene expression analyses 24 hours following pathogen exposure indicate that symbiotic animals mounted a more damaging immune response, with higher levels of inflammation and oxidative stress likely resulting in more severe disruptions to cellular homeostasis. Underlying this more damaging immune response may be differences in constitutive and pathogen-induced expression of immune transcription factors between aposymbiotic and symbiotic polyps rather than broadscale immune suppression during symbiosis. Our findings indicate that in facultatively symbiotic polyps, hosting symbionts limits C. xamachana's ability to survive pathogen exposure, indicating a trade-off between symbiosis and immunity that has potential implications for coral disease research. [ABSTRACT FROM AUTHOR]

The honey bee, Apis mellifera L., is one of the main pollinators worldwide. In a temperate climate, seasonality affects the life span, behavior, physiology, and immunity of honey bees. In consequence, it impacts their interaction with pathogens and parasites. In this study, we used Bayesian statistics and modeling to examine the immune response dynamics of summer and winter honey bee workers after injection with the heat-killed bacteria Serratia marcescens, an opportunistic honey bee pathogen. We investigated the humoral and cellular immune response at the transcriptional and functional levels using qPCR of selected immune genes, antimicrobial activity assay, and flow cytometric analysis of hemocyte concentration. Our data demonstrate increased antimicrobial activity at transcriptional and functional levels in summer and winter workers after injection, with a stronger immune response in winter bees. On the other hand, an increase in hemocyte concentration was observed only in the summer bee population. Our results indicate that the summer population mounts a cellular response when challenged with heat-killed S. marcescens, while winter honey bees predominantly rely on humoral immune reactions. We created a model describing the honey bee immune response dynamics to bacteria-derived components by applying Bayesian statistics to our data. This model can be employed in further research and facilitate the investigating of the honey bee immune system and its response to pathogens. [ABSTRACT FROM AUTHOR]

Lipases are hydrolytic enzymes which have significant potential for commercial applications, particularly in the breakdown of oil contaminants. Serratia marcescens EGHK-19 isolate exhibited considerable lipase activity. This study investigates the optimization, purification, and characterization of lipase from the Serratia marcescens EGHK-19 isolate. The optimized culture conditions revealed that maximal lipase activity was achieved after 24 hours at 30°C and pH 7, with continuous shaking at 150 rpm. Utilizing a 2% inoculum percentage with 1% diesel and 0.3% tryptone in the presence of Fe2+, Ca2+, Mg2+ salts, and Tween 80 resulted in the highest activity at 17.278 U/ml/min. The purification process involved acetone precipitation and DEAE-Sephadex column chromatography, revealing a molecular weight of approximately 60 kDa on SDS-PAGE. This method exhibited a 0.985-fold purification, and the final yield was limited to 2.097% due to lipase aggregates. Characterization of the purified lipase indicated optimal activity (8.765 U/mL/min) at 40°C a nd p H 7. T he K m a nd V max values w ere c alculated a s 6 .89 m M a nd 6 5.79 µmol/min, respectively. The presence of SDS, Tween 80, and Triton X-100 surfactants resulted in the inhibition of lipase activity. Despite these insuggestss, the biochemical characteristics of the purified lipase suggest its potential as an excellent candidate for various industrial applications. [ABSTRACT FROM AUTHOR]

Background The incidence of spine infections has increased due to the surge in injection drug use driven by the opioid epidemic. Few recent studies have evaluated the microbiology of spinal epidural infections among people who inject drugs compared to the microbiology of such infections among the general population. Methods We performed a retrospective chart review to identify patients with a spinal epidural abscess or phlegmon unrelated to recent spine surgery between 2015 and 2023. Results Of 346 initial records, 277 met inclusion criteria for demographic analyses. Of the 229 patients with microbiologic results, details regarding possible drug use were available in 227 patients. Patients with no documented history of drug use were categorized as non-PWUD, while patients who use drugs (PWUD) were separated based on whether drug use was active or not. Patients with prior histories of injection or noninjection drug use were categorized as nonactive PWUD, while those with injection or snorting drug use reported in the past 3 months were categorized as active PWUD. Thirty-nine percent of patients with spinal epidural infection had substance use disorder. Most patients with monomicrobial cultures were infected with gram-positive, aerobic bacteria (86%). Active PWUD were more likely to have methicillin-resistant Staphylococcus aureus compared to non-PWUD (36% vs 13%, respectively, P =.002). Nonactive PWUD were more likely to have non– Escherichia coli gram-negative bacterial infections than non-PWUD (18% and 4.4%, respectively, P =.01). Conclusions More than 1 in 3 patients with a spinal epidural infection unrelated to recent surgery had substance use disorder. These patients are more likely to have infections due to MRSA and gram-negative bacteria other than E coli such as Serratia marcescens. [ABSTRACT FROM AUTHOR]

Serratiopeptidase is a zinc-containing metalloprotease primarily obtained from Serratia marcescens isolated from the silkworm guts. This study aimed to assess the antinociceptive, anti-inflammatory, and antipyretic effects of serratiopeptidase in hen chicks. It included 104 hen chicks weighing 70-90 g. The antinociception efficacy was assessed by electrical-stimulation and hot-water test. Anti-inflammatory efficacy was assessed by formalin test. Assessment of therapeutic and antipyretic efficacy was determined by Baker's yeast-induced pyrexia test. In the electrical-stimulation test, 20 and 40 mg/kg of serratiopeptidase induced an antinociceptive effect in 15% and 18%, respectively. In the hot-water test, this effect was observed in 31 and 82%, respectively. In the first phase of the formalin test, an antinociceptive effect was observed for both doses, whereas in the second stage, an anti-inflammatory effect was observed in 56% and 62%, respectively. Serratiopeptidase produced a novel antipyretic effect for both doses on the Baker's-yeast test, pre- and post-injection of the yeast. It was concluded that serratiopeptidase had good activity against pain and acute inflammation, and for the first time, it was demonstrated that serratiopeptidase ameliorated and prevented hyperthermia. [ABSTRACT FROM AUTHOR]

In this research, biogenic selenium nanoparticles were produced by the fungi Yarrowia lipolytica, and the biological activity of its nanoparticles was studied for the first time. The electron microscopy analyses showed the production of nanoparticles were intracellular and the resulting particles were extracted and characterized by XRD, zeta potential, FESEM, EDX, FTIR spectroscopy and DLS. These analyses showed amorphous spherical nanoparticles with an average size of 110 nm and a Zeta potential of −34.51 ± 2.41 mV. Signatures of lipids and proteins were present in the capping layer of biogenic selenium nanoparticles based on FTIR spectra. The antimicrobial properties of test strains showed that Serratia marcescens, Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis were inhibited at concentrations between 160 and 640 μg/mL, while the growth of Candida albicans was hindered by 80 μg/mL of biogenic selenium nanoparticles. At concentrations between 0.5 and 1.5 mg/mL of biogenic selenium nanoparticles inhibited up to 50% of biofilm formation of Klebsiella pneumonia, Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa. Additionally, the concentration of 20–640 μg/mL of these bioSeNPs showed antioxidant activity. Evaluating the cytotoxicity of these nanoparticles on the HUVEC and HepG2 cell lines did not show any significant toxicity within MIC concentrations of SeNPs. This defines that Y. lipolytica synthesized SeNPs have strong potential to be exploited as antimicrobial agents against pathogens of WHO concern. [ABSTRACT FROM AUTHOR]

Bacteria are major drivers of organic matter decomposition and play crucial roles in global nutrient cycling. Although the degradation of dead fungal biomass (necromass) is increasingly recognized as an important contributor to soil carbon (C) and nitrogen (N) cycling, the genes and metabolic pathways involved in necromass degradation are less characterized. In particular, how bacteria degrade necromass containing different quantities of melanin, which largely control rates of necromass decomposition in situ, is largely unknown. To address this gap, we conducted a multitimepoint transcriptomic analysis using three Gram-negative, bacterial species grown on low or high melanin necromass of Hyaloscypha bicolor. The bacterial species, Cellvibrio japonicus, Chitinophaga pinensis, and Serratia marcescens, belong to genera known to degrade necromass in situ. We found that while bacterial growth was consistently higher on low than high melanin necromass, the CAZyme-encoding gene expression response of the three species was similar between the two necromass types. Interestingly, this trend was not shared for genes encoding nitrogen utilization, which varied in C. pinensis and S. marcescens during growth on high vs low melanin necromass. Additionally, this study tested the metabolic capabilities of these bacterial species to grow on a diversity of C and N sources and found that the three bacteria have substantially different utilization patterns. Collectively, our data suggest that as necromass changes chemically over the course of degradation, certain bacterial species are favored based on their different ial metabolic capacities. IMPORTANCE Fungal necromass is a major component of the carbon (C) in soils as well as an important source of nitrogen (N) for plant and microbial growth. Bacteria associated with necromass represent a distinct subset of the soil microbiome and characterizing their functional capacities is the critical next step toward understanding how they influence necromass turnover. This is particularly important for necromass varying in melanin content, which has been observed to control the rate of necromass decomposition across a variety of ecosystems. Here we assessed the gene expression of three necromass-degrading bacteria grown on low or high melanin necromass and characterized their metabolic capacities to grow on different C and N substrates. These transcriptomic and metabolic studies provide the first steps toward assessing the physiological relevance of up-regulated CAZyme-encoding genes in necromass decomposition and provide foundational data for generating a predictive model of the molecular mechanisms underpinning necromass decomposition by soil bacteria. [ABSTRACT FROM AUTHOR]

Urease-producing bacteria (UPB) are widely present in soil and play an important role in soil ecosystems. In this study, 65 UPB strains were isolated from cadmium (Cd)-polluted soil around a lead-zinc mine in Yunnan Province, China. The Cd tolerance, removal of Cd from aqueous solution, production of indoleacetic acid (IAA) and plant growth-promoting effects of these materials were investigated. The results indicate that among the 65 UPB strains, four strains with IAA-producing ability were screened and identified as Bacillus thuringiensis W6-11, B. cereus C7-4, Serratia marcescens W11-10, and S. marcescens C5-6. Among the four strains, B. cereus C7-4 had the highest Cd tolerance, median effect concentration (EC50) of 59.94 mg/L. Under Cd 5 mg/L, S. marcescens C5-6 had the highest Cd removal from aqueous solution, up to 69.83%. Under Cd 25 mg/kg, inoculation with B. cereus C7-4 significantly promoted maize growth in a sand pot by increasing the root volume, root surface area, and number of root branches by 22%, 29%, and 20%, respectively, and plant height and biomass by 16% and 36%, respectively, and significantly increasing Cd uptake in the maize roots. Therefore, UPB is a potential resource for enhancing plant adaptability to Cd stress in plants with Cd-polluted habitats. STATEMENT OF NOVELTY: This study utilized urease-producing bacteria screened from the soil of lead zinc mining areas in Yunnan, China as the research object, enriching the microbial resources in Yunnan. In addition, this article verified the IAA production ability and cadmium removal ability of urease-producing bacteria, and screened out bifunctional urease-producing bacteria that have potential in cadmium pollution control and plant growth promotion. [ABSTRACT FROM AUTHOR]

Endophytic fungi are known to be a rich source for anti-infective drugs. In this study, Aptenia cordifolia associated endophytic fungi were explored for the first time. Seven isolates were identified morphologically followed by screening of these fungi by plug diffusion assay which revealed their potential activity against Staphylococcus aureus (ATCC 9144), Bacillus cereus (ATCC 14579), Serratia marcescens (ATCC 14756), Fusarium oxysporum (ATCC 48112), and Aspergillus flavus (ATCC 22546). Additionally, the crude ethyl acetate extract of the most potent three isolates in plug diffusion assay showed that Aspergillus sp. ACEFR2 was the most potent as anti-infective in disc diffusion assay; Accordingly, Aspergillus sp. ACEFR2 was investigated using phylogenetic analysis and LC-HR-ESI-MS. The phylogenetic analysis placed the strain into the Aspergillus section Niger close related to few species including A. niger. Whereas the metabolomic profiling revealed the presence of diverse pool of metabolites. Furthermore, in silico molecular docking study was carried out to predict which compounds most likely responsible for the anti-infective activity. [ABSTRACT FROM AUTHOR]

Improving food preservation technologies is a key aspect in the struggle to reduce global food waste, and natural antimicrobial substances, such as essential oil (EO) components represent very promising food preserving agent. However, their intrinsic chemico‐physical properties, such as the low melting point, low water solubility and high volatility, pose some practical difficulties in exploiting them for practical applications. Cocrystallization is used to stabilize liquid or volatile EO components providing them whit a crystalline environment, thus improving their potential application as antibacterial agents. Five EO active ingredients (THY = thymol, CAR = carvacrol, EUG = eugenol, CAD = trans‐cinnamaldehyde, and VAN = o‐vanillin) and two coformers (INA = Isonicotinamide, and HBA = 4‐hydroxybenzoic acid) have been combined and the corresponding cocrystals have been studied for their potential inhibiting effect against four food spoilage bacteria (Bacillus thuringiensis, Enterobacter cloacae, Pseudomonas fluorescens, and Serratia marcescens). The structures of the five cocrystals have been used to derive structure‐activity relationships in terms of release energy of the active ingredients form the crystalline environment, and a correlation has been derived with the Intermolecular Interaction Energies of the EO molecules. [ABSTRACT FROM AUTHOR]

The study successfully produced a hybrid nanocomposite of silver nanoparticles embedded with end-of-life battery-derived sheets-like nitrogen and sulfur-doped reduced-graphene oxide (AgNPs@NSG), which was utilized to remove methylene blue (MB) and paracetamol (PC) from aqueous solutions. The AgNPs@NSG nanocomposite was analyzed using various techniques. Several conditions, including pH value, adsorbent dose, initial concentration, and contact time, were studied to improve the removal efficiency of MB and PC. The pseudo-second-order model was the best fit for both MB and PC adsorption kinetics. The Langmuir model effectively described the experimental data for the adsorption isotherm, with maximum adsorption capacities of 61.72 and 52.6 mg/g for MB and PC, respectively, at room temperature. Additionally, the AgNPs@NSG nanocomposite demonstrated promising antibacterial activity against Gram-positive and Gram-negative bacteria. The nanocomposite showed inhibition zone diameters of 12.00 mm for Bacillus subtilis, 10.33 mm for Staphylococcus aureus, 9.67 mm for Streptococcus mutans, 10.00 mm for Escherichia coli, 11.33 mm for Proteus vulgaris, 9.67 mm for Serratia marcescens, and 10.67 mm for Vibrio parahaemolyticus. These results indicate the potential of AgNPs@NSG for reducing microorganism infections, especially in wastewater treatment. Overall, this study presents a simple and cost-effective process for producing an efficient material to remove harmful pollutants from wastewater. It also demonstrates its additional antimicrobial properties, highlighting its potential for versatile applications in environmental cleanup and infection control. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) poses a significant global health threat, necessitating the development of novel antibacterial strategies. Serratiopeptidase (SP), a metalloprotease produced by bacteria such as Serratia marcescens, has gained attention not only for its anti-inflammatory properties but also for its potential antibacterial activity. However, its protein nature makes it susceptible to pH changes and self-proteolysis, limiting its effectiveness. This study aimed to increase both the enzymatic stability and antibacterial activity of serratiopeptidase through immobilization on titanium oxide nanoparticles (TiO2-NPs), leveraging the biocompatibility and stability of these nanomaterials. Commercial TiO2-NPs were characterized using TGA/DTG, FT-IR, UV–Vis, and XRD analyses, and their biocompatibility was assessed through cytotoxicity studies. Serratiopeptidase was produced via fermentation using the C8 isolate of Serratia marcescens obtained from the intestine of Bombyx mori L., purified chromatographically, and immobilized on carboxylated nanoparticles via EDC/NHS coupling at various pH conditions. The optimal enzymatic activity was achieved by using pH 5.1 for nanoparticle activation and pH 5.5 for enzyme coupling. The resulting bioconjugate demonstrated stable proteolytic activity at 25 °C for 48 h. Immobilization was confirmed by FT-IR spectroscopy, and the Michaelis–Menten kinetics were determined. Notably, the bioconjugate exhibited two-fold greater antibacterial activity against E. coli than the free enzyme or TiO2-NPs at 1000 µg/mL. This study successfully developed a serratiopeptidase–TiO2 bioconjugate with enhanced enzymatic stability and antibacterial properties. The improved antibacterial activity of the immobilized enzyme presents a promising approach for developing new tools to combat antimicrobial resistance, with potential applications in healthcare, food safety, and environmental protection. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Zinc deficiency is a significant global health concern, affecting around two billion people due to insufficient dietary intake. The extensive utilization of cereal-based meals with inadequate zinc content and limited bioavailability stands as the primary cause for this issue. Children who possess low levels of zinc experience stunted growth and developmental delays. They also have higher rates of morbidity from pneumonia, diarrhoea, and malaria. Inadequate zinc intake has been correlated with a heightened risk of mortality in children due to specific diseases. It is crucial to secure a satisfactory level of zinc in rice grains because of its indispensable function in various biochemical processes that are fundamental for the growth and advancement of plants. A deficiency in zinc can lead to reduced grain yield and nutritional value in rice. Recently, the utilization of registered biofertilizers and microbial technology is widely recognized in contemporary intensive farming practices. Some indigenous zinc-solubilizing bacterial strains discovered can increase rice yield and zinc content in grains. The objective of this study was to impact of a biofertilizer formula consisting of native zinc solubilizer strains on the growth, productivity, and zinc concentration in the grains of three rice varieties, namely Inpari IR Nutrizinc, Inpari 48, and Inpago 13 Fortiz. The study was conducted in a paddy field located in the Inceptisol of Subang Regency, West Java, during the year 2023. METHODS: The field trial was conducted to study the impact of a biofertilizer comprising a group of non-pathogenic zinc-solubilizing bacteria, including Enterobacter cloacae, Klebsiella pneumoniae, Serratia marcescens, Bacillus thuringiensis, and Enterobacter bugandensis on rice growth, yield, zinc levels, and uptake in grains. The rhizosphere soils were the origin of these bacteria, which were obtained using agar media containing zinc oxide as insoluble zinc compounds. Prior to this, the bacterial strains were evaluated for their capacity to dissolve zinc and generate the plant hormone indole-3-acetic acid. To gauge their zinc-solubilizing prowess, Pikovskaya agar media, supplemented with insoluble zinc oxide and calcium phosphate, respectively, were utilized. The presence of distinct clear areas surrounding the colonies demonstrated the effectiveness of the microbes in converting insoluble zinc and phosphorus into soluble forms. The concentration of the plant hormone indole-3-acetic acid was measured using the Salkowski reagent. The field trial was organized using a split-plot design with three replications. The application of the biofertilizer mixture as a seed treatment was carried out before the transplantation of the rice nursery. The seedlings were prepared individually for each rice variety, with a comparison made between those treated with the biofertilizer and those that were not. FINDINGS: The study found that the consortium of indigenous non-pathogenic zinc-solubilizing bacteria significantly increased the yield of rice varieties by about 5.6 percent and zinc content in grains by 16.3 percent. However, the application of zinc containing fertilizer treatments did not enhance the rice yield and zinc content in grains in this Inceptisol paddy soil. In terms of zinc content in grains, the rice variety Inpago 13 Fortiz exhibited a notable increase compared to the Inpari IR Nutrizinc variety, with levels of 40.3 milligrams per kilogram as opposed to 34.1 milligrams per kilogram. CONCLUSION: the utilization of a native combination of carefully chosen zinc-solubilizing bacterial strains could augment the productivity, zinc concentration, and absorption in rice grains of various varieties in a paddy field with Inceptisols soil type, characterized by a moderate to high overall zinc content and limited zinc accessibility. The addition of zinc containing fertilizer treatments did not enhance rice yield compared to the addition of other tratments or control. This is probably because of the medium-high level of the total zinc content of the soil, suggesting that the addition of Biofertizinc will reduce or delete the crop requirement for zinc fertilizer in Inceptisol paddy fields. This implies that the biofertilizer is ecologically sustainable as it eliminates the use of harmful chemicals, reduces the reliance on synthetic fertilizers, and lowers costs. [ABSTRACT FROM AUTHOR]

Effects of heavy metals on soil microbial communities have been extensively studied due to their persistence in the environment and imposed threats to living organisms; however, there is a lack of in-depth studies of the impacts of heavy metals on plant endophyte communities. Therefore, the responses of plant endophyte communities to different concentrations of heavy metals were investigated in this study. The endophyte communities of plants existing in severely (W1, Pb, 110.49 mg/kg, Cd, 1.11 mg/kg), moderately (W2, Pb, 55.06 mg/kg, Cd, 0.48 mg/kg), and mildly (W3, Pb, 39.06 mg/kg, Cd, 0.20 mg/kg) contaminated soils were analyzed by 16s rRNA high-throughput Illumina sequencing. Furthermore, networks were constructed to illustrate the relationships between microorganisms and environmental factors. High-quality sequences were clustered at a 97% similarity level. Results revealed that the diversity of the community and relative abundance of Cyanobacteria phylum increased with decreasing levels of pollution. Cyanobacteria and Proteobacteria were found to be the dominant phylum, while Methylobacterium and Sphingomonas were observed as the dominant genus. Tukey's HSD test showed that the relative abundances of Cyanobacteria and Proteobacteria phyla and Methylobacterium and Sphingomonas genera differed significantly (p < 0.01) among the plants of the three sample sites. Environmental factor analysis revealed a significant negative correlation (p < 0.01) of Cyanobacteria and a significant positive correlation (p < 0.01) of Methylobacterium with the heavy metal content in the environment. These findings suggest that Cyanobacteria and Methylobacterium may be phylum and genus indicators, respectively, of heavy metal toxicity. Tax4Fun analysis showed the effect of heavy metal toxicity on the abundance of genes involved in plant metabolism. In addition, culturable endophytic strains were isolated to study their resistance to heavy metal stress and their ability to promote plant growth. The potting tests showed that the JG1 strain was tolerant to heavy metals, and it could significantly promote the growth of the host plant under stress caused by multiple heavy metals. Compared to the control, the JG1-treated plants showed a 23.14% increase in height and a 12.84% increase in biomass. Moreover, AP, AK, and HN contents in JG1-treated plants were 20.87%, 12.55%, and 9.03% higher, respectively, under heavy metal stress. The results of this study provide a scientific basis for the construction of an efficient plant endophyte restoration system. [ABSTRACT FROM AUTHOR]

AmpC enzymes are a class of beta-lactamases produced by Gram-negative bacteria, including several Enterobacterales. When produced in sufficient amounts, AmpCs can hydrolyze third-generation cephalosporins (3GCs) and piperacillin/tazobactam, causing resistance. In Enterobacterales, the AmpC gene can be chromosomal- or plasmid-encoded. Some species, particularly Enterobacter cloacae complex, Klebsiella aerogenes, and Citrobacter freundii, harbor an inducible chromosomal AmpC gene. The expression of this gene can be derepressed during treatment with a beta-lactam, leading to AmpC overproduction and the consequent emergence of resistance to 3GCs and piperacillin/tazobactam during treatment. Because of this phenomenon, the use of carbapenems or cefepime is considered a safer option when treating these pathogens. However, many areas of uncertainty persist, including the risk of derepression related to each beta-lactam; the role of piperacillin/tazobactam compared to cefepime; the best option for severe or difficult-to-treat cases, such as high-inoculum infections (e.g., ventilator-associated pneumonia and undrainable abscesses); the role of de-escalation once clinical stability is obtained; and the best treatment for species with a lower risk of derepression during treatment (e.g., Serratia marcescens and Morganella morganii). The aim of this review is to collate the most relevant information about the microbiological properties of and therapeutic approach to AmpC-producing Enterobacterales in order to inform daily clinical practice. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Aims Patients/Methods Results Conclusions The field of cosmetic filler injection has experienced rapid development over the past two decades, especially in facial augmentation utilizing hyaluronic acid (HA) fillers. Gram‐negative bacteria are found to be the main pathogens of infective nodules after HA injection. The occurrence of cutaneous infections attributed to Serratia marcescens is exceedingly rare and predominantly noted in patients with compromised immune systems.To summarize the clinical features, diagnosis, and treatment of subcutaneous infection caused by Serratia marcescens following hyaluronic acid injection.A rare case of cutaneous Serratia marcescens infection following hyaluronic acid injection was presented. A comprehensive review of the published literature describing the management of skin infection caused by S. marcescens in immunocompetent patients was then conducted, which encompassed three case series and eight case reports published between 1999 and 2017. Data extraction included information on authors, gender, age, signs and symptoms, previous treatment, corresponding management strategies, and follow‐up duration.Serratia marcescens were isolated in abscesses (n = 6, 35.29%), painful nodules (n = 2, 11.76%), ulcers (n = 6, 35.29%), and others (n = 3, 17.65%). In cases providing salvage plans (n = 11), quinolones were shown to be the most effective antibiotics for salvage, with eight full recoveries (72.73%), and trimethoprim‐sulfamethoxazole was the second most useful antibiotic (18.18%).With the help of pathogen examination and drug‐sensitive tests, sensitive aminoglycosides, quinolone (especially moxifloxacin), or TMP‐SMX for at least 2 weeks can be considered as the first‐line treatment of late subcutaneous infection caused by Serratia marcescens following hyaluronic acid injection. [ABSTRACT FROM AUTHOR]

Biofilms currently represent the most prevalent bacterial lifestyle, enabling them to resist environmental stress and antibacterial drugs. Natural antibacterial agents could be a safe solution for controlling bacterial biofilms in food industries without affecting human health and environmental safety. A methanolic extract of Azadirachta indica (neem) leaves was prepared and analyzed using gas chromatography–mass spectrometry for the identification of its phytochemical constituents. Four food-borne bacterial pathogens (Bacillus cereus, Novosphingobium aromaticivorans, Klebsiella pneumoniae, and Serratia marcescens) were tested for biofilm formation qualitatively and quantitatively. The antibacterial and antibiofilm properties of the extract were estimated using liquid cultures and a microtiter plate assay. The biofilm inhibition mechanisms were investigated using a light microscope and molecular docking technique. The methanolic extract contained 45 identified compounds, including fatty acids, ester, phenols, flavonoids, terpenes, steroids, and antioxidants with antimicrobial, anticancer, and anti-inflammatory properties. Substantial antibacterial activity in relation to the extract was recorded, especially at 100 μg/mL against K. pneumoniae and S. marcescens. The extract inhibited biofilm formation at 100 μg/mL by 83.83% (S. marcescens), 73.12% (K. pneumoniae), and 54.4% (N. aromaticivorans). The results indicate efficient biofilm formation by the Gram-negative bacteria S. marcescens, K. pneumoniae, and N. aromaticivorans, giving 0.74, 0.292, and 0.219 OD at 595 nm, respectively, while B. cereus was found to have a low biofilm formation potential, i.e., 0.14 OD at 595 nm. The light microscope technique shows the antibiofilm activities with the biofilm almost disappearing at 75 μg/mL and 100 μg/mL concentrations. This antibiofilm property was attributed to DNA gyrase inhibition as illustrated by the molecular docking approach. [ABSTRACT FROM AUTHOR]

The presence of pathogenic bacteria is a problem that might be present in farmed shrimp due to exposure in the environment or post‐harvest handling. Retail farmed shrimp in Bangladesh (Penaeus monodon and Macrobrachium rosenbergii) were tested for common pathogenic bacteria namely Salmonella, L. monocytogenes, Vibrio spp., and E. coli. None of these bacteria were found and instead Enterobacter cloacae, Escherichia fergusonii, Proteus penneri, Klebsiella aerogenes, Enterococcus faecalis, Serratia marcescens, Citrobacter freundii, and Aeromonas dhakensis were detected. Pathogenic bacteria found in Bangladeshi shrimp may be due to the farm environment, poor handling during harvest or post‐harvest, or unhygienic market conditions. The results indicate that retail shrimp from Bangladesh have food safety concerns. Proper laws and policies need to be enforced and implemented to ensure food safety related to fish and shrimp. [ABSTRACT FROM AUTHOR]

This study investigated the chemical composition and antibacterial activities of lime Citrus aurantifolia (Cc) and lemon grass Cymbopogon citratus (Ca) essential oils (EOs). Standard methods were used to determine their minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC), and gas chromatography-mass spectrometry was used to determine their composition. Each EO and their combination showed promising results in treating test bacterial infections. Cc EO showed the largest inhibition zone diameter (43 mm) against Staphylococcus aureus and Serratia marcescens, and Ca EO showed the largest (30 mm) and smallest (12 mm) inhibition zone diameters against Bacillus stearothermophilus and S. marcescens, respectively. The combination of Cc EO and Ca EO (1:1) resulted in the largest (45 mm) and smallest (8 mm) inhibition zone diameters against Klebsiella pneumoniae and Salmonella typhimurium, respectively. The MIC of Cc EO ranged from 0.78% to 6.25%, and its MBC ranged from 3.13% to 12.50%. The MIC and MBC of combined Cc EO and Ca EO ranged from 0.78% to 6.25% and from 1.56% to 12.5%, respectively. The major components of Cc EO and Ca EO were neral (44.98%) and D-limonene (56.02%). Overall, the combination of lime and lemon grass EOs performed well compared to streptomycin, making them suitable for treating test bacterial infections. [ABSTRACT FROM AUTHOR]

Aims To construct an efficient bacterial complex to degrade nicosulfuron and clarify its degradative characteristics, promote the growth of maize (Zea mays), and provide a theoretical foundation for the efficient remediation of soil contaminated with nicosulfuron. Methods and results Biocompatibility was determined by the filter paper sheet method by mixing Serratia marcescens A1 and Bacillus cereus A2 in a 1:1 ratio, yielding A12. The optimum culture conditions for the bacterial composite were obtained based on a three-factor, three-level analysis using response surface methodology, with 29.25 g l−1 for maltodextrin, 10.04 g l−1 for yeast extract, and 19.93 g l−1 for NaCl, which resulted in 92.42% degradation at 4 d. The degradation characteristics of A12 were clarified as follows: temperature 30°C, pH 7, initial concentration of nicosulfuron 20 mg l−1, and 4% inoculum. The ability to promote growth was determined by measuring the ratio of the lysosphere diameter (D) to the colony diameter (d), and the ability of the complex A12 to promote growth was higher than that of the two single strains. Conclusions Nicosulfuron degradation in sterilized and unsterilized soils reached 85.4% and 91.2% within 28 d, respectively. The ability of the strains to colonize the soil was determined by extraction of total soil DNA, primer design, and gel electrophoresis. The bioremediation effect of A12 was confirmed by the maximum recovery of fresh weight (124.35%) of nicosulfuron-sensitive crop plants and the significant recovery of soil enzyme activities, as measured by the physiological indices in the sensitive plants. [ABSTRACT FROM AUTHOR]