Pathogenic Strains Research Articles

Genomic characterization of pathotype diversity and drug resistance among generic Escherichia coli isolated from broiler chickens in Canada

Escherichia coli is a Gram-negative bacterium that is ubiquitous in animals and humans, with some strains capable of causing disease. The aim of this study was to perform a comparative genomic analysis of 2,732 generic E. coli isolates that were recovered from poultry samples collected from six regions in Canada as part of the National Microbiological Baseline study in Broiler Chicken. Isolates were subjected to whole genome sequencing and a subset (1,122/2,732) were tested for phenotypic resistance to fifteen antimicrobials. These E. coli isolates were highly diverse, representing 376 serotypes, 236 Sequence Types and twenty-one pathotypes, of which 19 were hybrid pathotypes. A high concordance (>85%) between resistance phenotype and the presence of antimicrobial resistance genes and point mutations (resistance determinants) was observed for 13/15 antimicrobials. Over 95% of the β-lactam, fluoroquinolone, and phenicol resistance genes were predicted to be plasmid-borne. The number of resistance determinants per genome was highest in Quebec, while resistance genes associated with β-lactam resistance were more frequently detected in isolates from British Columbia. Generic E. coli in Canadian poultry are highly diverse, can carry pathotype-associated virulence factors and resistance determinants of clinical significance with a risk of emerging into pathogenic strains.

Novel tetracycline hybrids: synthesis, characterization, docking studies and in-vitro evaluation of antibacterial activity

BackgroundThe biggest menace in the world today is the infection caused by pathogenic bacteria in humans, where majority of the available antibiotics fail to provide therapeutic results due to resistance. The discovery of new molecules is the need of the hour and several research groups worldwide are contributing to fight this scare. This work highlights our efforts towards discovering novel tetracycline hybrids that could serve as potent agents against several pathogenic bacterial strains causing infections. In total, ten compounds were synthesized which were chemically conjugates of Minocycline, an age-old tetracycline, and naturally occurring aldehydes and ketones available from the plant sources. Structural characterization of these compounds was done using Mass and 1HNMR. Molecular docking was carried out in order to predict the binding affinity of these compounds to various bacterial enzymes and known protein targets and to establish the structure–activity relationships. Molecular dynamic simulation studies and in silico pharmacokinetic and toxicity prediction studies were done to determine in silico pharmacokinetics and toxicity of compounds. In-vitro antibacterial activities were done using standard protocols against gram positive bacteria like Enterococcus faecalis, Staphylococcus aureus and gram-negative bacteria like Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli.ResultsPromising results were obtained viz. compound 1,2 and 10 were found to be more potent against Staphylococcus aureus, compound 1 against Enterococcus faecalis, compound 2 and 3 against Escherichia coli, compound 7 and 8 against Pseudomonas aeruginosa and compound 7 against Klebsiella pneumoniae when compared with minocycline as standard compound.ConclusionAll the synthesized compounds were screened for their anti-bacterial activity against gram positive and gram negative microorganisms. Amongst the ten synthesized minocycline hybrids, four minocycline hybrids exhibited potent antibacterial activity as compared to minocycline. These hybrids can serve as a promising lead compound for antibiotic drug discovery.

Determination of Biological Control Agent Bacteria Against Crown Gall

This study was carried out to determine new bioagent bacteria for in vitro and semi-in vivo biological control of crown gall disease [Rhizobium radiobacter (Agrobacterium tumefaciens)]. A total of 2012 potential bioagent bacterial strains belonging to different genera were tested in vitro against the pathogen. Microbial identification systems (MIS) diagnoses of bioagent bacterial strains found to be effective as a result of in vitro tests were supported by some conventional tests. Then, the strains' semi-in vivo biocontrol activities found to be effective were tested in carrot slices and squash fruits. Statistical analysis of the data was made according to the percentage of surface coverage in carrot slices and the number and size of tumors in squash fruits. Then, the most effective bioagent and pathogenic bacterial strain diagnoses were determined molecularly. According to the results; 106 bioagent bacterial strains (66 antibiosis; 40 hyperparasitic effects) were found to be effective against R. radiobacter in vitro conditions. It was determined that conventional test results of bioagent bacteria and MIS results supported each other. As a result of semi-in vivo biocontrol activity, it was determined that 8 bioagent bacterial strains out of 106 bioagent bacterial strains did not produce pectolytic activity, and 8 bioagent bacterial strains could be evaluated as a result of semi-in vivo test. The most effective strain suppressing the development of the pathogen in carrot slices and squash fruits was RK 1986 (carrot slices 1.78±0.47; squash fruits 0.26±0.04), followed by RK 570A (carrot slices 2.89±0.82; squash fruits 0.35+0.03) and RK 1074 (carrot slices 3.44±0.99; squash fruits 0.46±0.05) strains were followed. According to the results of molecular identification, the most effective bioagent bacterial strain (RK 1986) was Bacillus mojavensis, and the pathogenic bacteria strain (1B) was R. radiobacter.

Highly pathogenic bovine viral diarrhea virus BJ-11 unveils genetic evolution related to virulence in calves

Bovine viral diarrhea virus (BVDV) is the causative agent of bovine viral diarrhea, which causes significant economic loss to the global livestock industry. Despite the widespread use of inactivated BVDV vaccines, highly pathogenic strains continue to emerge. In China, regional variations in BVDV subtypes, morbidities, and symptoms, however, only the BVDV 1a subtype vaccine is currently approved. Therefore, this study is to gain insight into the biological characteristics and genetic variation of BVDV strains prevalent in Beijing. Meanwhile, this will provide a theoretical foundation and technical support for the prevention and control of BVDV, as well as raise awareness of the potential for virulence enhancement caused by the unregulated use of BVDV vaccines. In this study, A BVDV strain, BJ-11, was isolated from calves that died of diarrhea and vaccinated of BVDV. To evaluate its virulence, newborn calves were experimentally infected with the BJ-11. Clinical signs included fever, diarrhea, bloody stools, anorexia, and death in some cases. A marked reduction in leukocyte and lymphocyte counts were observed, accompanied by an increase in neutrophil counts. Histopathological changes manifested as severe lung lesions. Phylogenetic analysis indicated that BJ-11 belongs to the BVDV 1b subtype, genetically closest to the JL-1 strain. Analysis of the E2 glycosylation site disappeared (298SYT) in one of the four common glycosylation sites in the BVDV-1, which has been reported to affect the ability of the virus to infect and an additional glycosylation site (122NGS). These results indicate that BJ-11 is a highly pathogenic strain evolved from a low-virulence ancestor and should be served as a challenge strain. Simultaneously, these results contribute to a broader understanding of BVDV and whether imperfect vaccination strategies lead to reversal of immunosuppressive virulence.

Skin Microbiota: Mediator of Interactions Between Metabolic Disorders and Cutaneous Health and Disease

Metabolic disorders, including type 2 diabetes mellitus (T2DM), obesity, and metabolic syndrome, are systemic conditions that profoundly impact the skin microbiota, a dynamic community of bacteria, fungi, viruses, and mites essential for cutaneous health. Dysbiosis caused by metabolic dysfunction contributes to skin barrier disruption, immune dysregulation, and increased susceptibility to inflammatory skin diseases, including psoriasis, atopic dermatitis, and acne. For instance, hyperglycemia in T2DM leads to the formation of advanced glycation end products (AGEs), which bind to the receptor for AGEs (RAGE) on keratinocytes and immune cells, promoting oxidative stress and inflammation while facilitating Staphylococcus aureus colonization in atopic dermatitis. Similarly, obesity-induced dysregulation of sebaceous lipid composition increases saturated fatty acids, favoring pathogenic strains of Cutibacterium acnes, which produce inflammatory metabolites that exacerbate acne. Advances in metabolomics and microbiome sequencing have unveiled critical biomarkers, such as short-chain fatty acids and microbial signatures, predictive of therapeutic outcomes. For example, elevated butyrate levels in psoriasis have been associated with reduced Th17-mediated inflammation, while the presence of specific Lactobacillus strains has shown potential to modulate immune tolerance in atopic dermatitis. Furthermore, machine learning models are increasingly used to integrate multi-omics data, enabling personalized interventions. Emerging therapies, such as probiotics and postbiotics, aim to restore microbial diversity, while phage therapy selectively targets pathogenic bacteria like Staphylococcus aureus without disrupting beneficial flora. Clinical trials have demonstrated significant reductions in inflammatory lesions and improved quality-of-life metrics in patients receiving these microbiota-targeted treatments. This review synthesizes current evidence on the bidirectional interplay between metabolic disorders and skin microbiota, highlighting therapeutic implications and future directions. By addressing systemic metabolic dysfunction and microbiota-mediated pathways, precision strategies are paving the way for improved patient outcomes in dermatologic care.

Chemical composition and antimicrobial properties of the essential oil from Morinda royoc L. fruit

The present study was carried out to evaluate the chemical composition and antimicrobial properties of the essential oil from fruits of Morinda royoc L. Essential oil was extracted from fruit by the hydrodistillation method. For this study, GC-FID and GC-MS were used for the characterization of the volatile compounds. One hundred twenty-five volatile constituents were identified in a total yield of 0.18% (v/m). Octanoic acid (50.5%), 3-methyl-3-buten-1-yl octanoate (13.9%) and decanoic acid (6.7%) were found the major compounds. Antimicrobial activity of the essential oil was observed against seven foodborne pathogenic strains. The essential oil exhibited very good activity against B. subtilis, S. aureus, C. albicans, and C. utilis, good activity against E. coli, but it showed moderate activity against S. enterica serovar and low activity against P. aeruginosa. The MIC values of the essential oil varied from 2.10 to 23.05 μg/ mL, with the lowest for C. albicans. This study could have valuable industrial applications, particularly in the food, nutraceutical, and pharmaceutical sectors.

Pathogenic potential of ornithogenic <i>Escherichia coli</i> strains detected in the Earth's polar regions

Introduction. Pathogenic strains of Escherichia coli are an important object of surveillance within the One Health concept in the wild, agriculture and human society. Migratory bird colonies and high latitude avian colonies may be points of active intraspecies and interspecies contact between different animal species, accompanied by the spread of pathogens. At the same time, the phylogeography of E. coli in relation to the presence of natural foci of colibacillosis in polar regions remains virtually unstudied. The aim of this study was to assess the pathogenic potential of E. coli strains from the polar regions of the Earth, based on the analysis of the genomes of these bacteria from typical ornithogenic ecosystems of the Arctic and Antarctic. Materials and methods. The study used collections of E. coli isolated from ornithogenic biological material during expeditions to high latitude areas of the Arctic (archipelagos of Novaya Zemlya, Franz Josef Land, Svalbard) and Antarctic (Haswell Archipelago). 16 cultures associated with avian E. coli (12 polar and 4 temperate strains) were selected for genome-wide sequencing using BGI technology. The annotation of the genomes focused on the identification of genes for pathogenicity factors and antimicrobial resistance, as well as the identification of strains belonging to individual genetic lineages using the cgMLST method. Results. The annotation of the genomes allowed their assignment to different sequence types in the multilocus sequencing typing and genome-wide sequencing typing schemes. The analysis of the geographical distribution of the sequence types of polar E. coli strains determined by the cgMLST method showed their global representation in geographically distant regions of the planet. For example, cgST 133718 was observed in Antarctica (strain 17_1myr) and in the UK, and sequence 11903, to which strain 32-1 from the northernmost point of Novaya Zemlya belonged, was previously identified in the USA. All strains studied were characterized by the presence of extensive virulence. Among the pathogenicity factors identified were haemolysins A, E, F, siderophores, including the yersiniabactin gene cluster, a number of adhesion, colonization and invasion factors, as well as the thermostable enterotoxin EAST-1 and genes that characterize enteroaggregative strains of E. coli (the virulence regulator gene eilA and enteroaggregative protein (air)). One of the Arctic strains (33-1) had determinants of antibiotic resistance, in particular the extended-spectrum beta-lactamase gene TEM-1b and the Tn1721 transposon, including tetracycline resistance genes (tetA-TetR), were detected in its genome. Conclusion. The results of the study indicate the circulation of E. coli strains with strong pathogenic potential in high-latitude Arctic and Antarctic ornithogenic ecosystems. The analysis of genomic data indicates the presence of geographically widespread genetic lineages in these regions, which justifies the importance of monitoring epidemic clones of E. coli, along with monitoring for other pathogens, in bird colonies in high-latitude areas.

Immobilization of Paenibacillus polymyxa with biopolymers to enhance the production of 2,3-butanediol

BackgroundPaenibacillus polymyxa, is a Gram-positive, plant growth promoting bacterium, known for producing 98% optically pure 2,3-butanediol, an industrially valuable chemical for solvents, plasticizers and resins. Immobilization of Paenibacillus polymyxa has been proposed to improve the cell stability and efficiency of the fermentation process, reduce contamination and provide easy separation of butanediol in the culture broth as compared to conventional bioprocesses. This research aimed to explore the potential of Paenibacillus polymyxa with immobilization technique to produce 2,3-butanediol.ResultsWe investigated different immobilization methods with natural biopolymers like alginate, chitosan and carrageenan-chitosan-based immobilization. These methods were further investigated for their immobilization efficiency and yield in 2,3-butanediol production. Carrageenan-chitosan beads enabled a higher cell concentration and demonstrated superior cell retention to calcium-alginate-chitosan beads. Carrageenan-chitosan immobilization preserved 2,3-butanediol production in bacteria and increased the product formation rate.ConclusionCarrageenan-chitosan immobilization enables non-pathogenic Paenibacillus polymyxa to be a capable 2,3-butanediol producer with increased product formation rate, which has not been previously reported. This novel strategy offers promising alternative to traditional fermentation processes using pathogenic strains and can be further applied in co-cultivations for metabolite production, wastewater management and bioremediation.

Molecular Detection of FIPV among Imported Felines through Soekarno Hatta Airport, Indonesia

One of the viruses that can cause disease in cats is feline coronavirus (FCoV). This virus is often divided into type I and type II. Type I is a highly pathogenic strain, feline infectious peritonitis virus (FIPV). Type II is a milder strain, feline enteric coronavirus (FECV). The FIPV variant is said to be a result of a mutation from FECV. FIP disease is responsible for 0.3%-1.4% of cat deaths in veterinary clinics. This study aims to determine if there is an FIPV in imported cats at Soekarno Hatta Airport, Indonesia. Samples were taken from 15 imported cats from Russia and Vietnam. These two countries were chosen based on previously unreported cases. The samples, consisting of blood and rectal swabs, were tested molecularly using RT-PCR. Four samples from rectal swabs showed positive results with a single band at 677 bp. Two positive samples, namely 123v and 682v, were further sequenced. The study results indicate that the FCoV virus can be found in asymptomatic imported cats. Further research is needed to better understand the mechanism causing genetic diversification of FCoV or FIPV and its impact on the pathogenesis of FIP. Furthermore, the application of FIP vaccines from other countries should be tested for compatibility with the FIPV strains present in Indonesia.

A large geno-spatial cluster of multi-drug resistant tuberculosis outbreak in a western district of Thailand.

The growing issue of drug resistance, particularly multidrug-resistant TB (MDR-TB), has exacerbated this problem. The rise of drug resistance TB is a severe global health concern. In Thailand, a persistent community outbreak of primary MDR-TB has been confirmed in the Tha Maka district of Kanchanaburi province, with an increasing prevalence of MDR-TB among newly diagnosed pulmonary tuberculosis cases. It was the first site in Thailand where a cluster of MDR-TB, caused by the Asian African 3 Modern Beijing strain, and XDR-TB, caused by L2.1, outbreaks were reported. This study aims to assess the MDR-TB outbreak in detail by characterizing the genomic profiles of the prevalent MDR-TB strains and examining their geographical distribution within the affected district. Through whole-genome sequencing (WGS) and bioinformatic analysis of 188 MTB isolates, the study identified three major phylogenetic lineages: the East Asian lineage (L2, 92 %), the Indo-Oceanic lineage (L1, 5.9 %), and the Euro-American lineage (L4, 2.1 %). The detailed sub-lineage distribution offers valuable insights into the predominant genetic clusters of M. tuberculosis within the sampled population. Notably, Lineage 2, specifically the L2.2.M3 sub-lineage, stood out as the dominant strain of MDR-TB, accounting for 77.7 % of the isolates. This finding underscores the significant prevalence of the L2.2.M3 sub-lineage and its potential role in the local transmission dynamics of tuberculosis. The high proportion and genetic homogeneity of the L2.2.M3 cluster among MDR-TB patients may indicate the strain's adaptation for more effective transmission within the Thai population. The increasing prevalence of this pathogenic strain could significantly impact tuberculosis control programs. Early diagnosis and contact tracing with chemotherapeutic preventive therapy for MDR-TB will be essential in inhibiting the spread and reactivation of these strains. Additionally, further studies are needed to prospectively identify transmission routes through contact tracing and real-time genotypic methods. It will also be crucial to ensure that future vaccines and/or recommended chemoprophylaxis therapy for MDR-TB will provide protection against these emerging strains.

Exploring nagZ as a virulence biomarker and treatment target in Enterobacter cloacae

BackgroundEnterobacter cloacae is increasingly prevalent and resistant to multiple antibiotics, making it a significant pathogen in healthcare settings with high mortality rates. However, its pathogenic mechanisms are not fully understood.ResultsIn this study, we explored the role of nagZ in regulating the virulence of E. cloacae and its potential as a therapeutic target. Our research showed that pathogenic strains of E. cloacae express higher levels of nagZ than colonizing strains, particularly in simulated infection environments. Deleting nagZ significantly reduced E. cloacae virulence in various infection models, including Galleria mellonella larvae, mice, and RAW264.7 cells. Moreover, nagZ knockout decreased the bacterium's ability to induce inflammatory factor levels, while complementing nagZ in knockout strains partially rescued this ability. Importantly, the absence of nagZ also enhanced the antibacterial efficacy of ceftazidime against E. cloacae.ConclusionsThese findings underscore the crucial role of nagZ in E. cloacae pathogenesis and highlight its potential as a novel therapeutic target for treating infections caused by this pathogen.

Characterization of a highly pathogenic porcine Teschoviruses 5 emerged in Western China.

Porcine teschovirus (PTV) is a devastating virus that targets the central nervous system and led to great economic losses in Europe between the 1920s and 1960s. Since 1973, PTV variants with lower pathogenicity have been prevalent globally, whereas highly pathogenic PTV strains have rarely emerged. In 2022, diarrhea with high mortality occurred on a pig farm in Gansu China. Virome analysis revealed that PTV was enriched among diarrheal samples. A PTV strain was then isolated and characterized by TEM, IFA, and growth kinetic features. Phylogenetic analyses revealed that the isolate shared an identity of approximately 90% with the most related PTV strain and with various mutant clusters among VP1. Further animal tests demonstrated that the isolate can result in serious respiratory distress, watery diarrhea, paralysis and high mortality in challenged pigs. H&E staining revealed the presence of lymphocyte cells infiltration and hemorrhage in the tissues. Overall, a PTV variant with high mortality was identified in western China, which could result in interstitial pneumonia, hemorrhage, and diarrhea. Although most PTV strains are associated with asymptomatic infection now, the sporadic occurrence of highly pathogenic PTVs is worthy of alarm.

Silver Nanoparticles for Anticancer and Antibacterial Therapy: A Biogenic and Easy Production Strategy

AbstractMetal nanoparticles are very valuable products due to their wide range of uses. Among these silver nanoparticles are beneficial products used in many fields, especially in medicine, due to their antibacterial properties. This research aimed to produce silver nanoparticles (Ag NPs) that are both affordable and environmentally friendly. For this purpose, Ag NPs were quickly obtained from domestic waste components of the carrot plant (Daucus carota L.). The UV–vis spectrophotometric, TEM, AFM, FE‐SEM, STEM, EDX, XRD, and DLS analyses were performed to determine the properties of the obtained Ag NPs. It has been found that their surface charge is −21.8 mV, with a maximum absorbance at a wavelength of 421.37 nm, spherical appearance, and an average size distribution of 85.41 nm. The anticancer and antibacterial activities of the produced Ag NPs were investigated by MTT and microdilution. The synthesized Ag NPs showed the most significant antimicrobial effect on Pseudomonas aeruginosa ATCC 27833 with microdilution and low concentration. However, they were also determined to be effective on Bacillus subtilis ATCC 11774 and on Candida albicans ATCC 10231 pathogenic strains. In fact, the effective concentrations of Ag NPs on these strains were significantly lower than the antibiotics used. Furthermore, aside from exhibiting a superior anticancer impact on CaCO‐2 cancer cells, it was established that Ag NPs also had remarkable efficacy in inhibiting U118 and Skov‐3 cancer cells.

Designing and evaluating a novel blood-brain barrier in vitro model of teleost for reproducing alterations in brain infecting

A new blood-brain barrier (BBB) in vitro model of tilapia (Oreochromis niloticus) was successfully established by co-culture with brain microvascular endothelial cell line TVEC-01 and brain astrocyte cell line TA-02 of tilapia. Experiments with the expression levels of BBB-related genes, TEER value detection and four-hour water-leaking test have shown that the BBB in vitro model has an excellent barrier effect. In bacterial penetration experiments, the pathogenic strain of Streptococcus agalactiae was able to pass through the BBB in vitro model and initiate a series of immune responses, among which TA-02 contributed to the expression of pro-inflammatory cytokines and TVEC-01 contributed to the expression of anti-inflammatory cytokines, providing an excellent research tool and theoretical basis for further study of meningitis. Moreover, the qRT-PCR and transmission electron microscopy revealed that the pathogenic strain of S. agalactiae effectively penetrated the BBB in vitro model of tilapia during early-stage infection without destroying tight junction integrity. This suggested that, in the initial phases of infection, the pathogenic strain of S. agalactiae may breach the BBB via a transcellular pathway rather than a paracellular pathway. Summarily, a novel BBB in vitro model of tilapia was successfully designed and evaluated for reproducing alterations in brain infecting.

ZnO-Rutin nanostructure as a potent antibiofilm agent against Pseudomonas aeruginosa

Pseudomonas aeruginosa is a common human pathogen that is resistant to multiple antibiotics due to its ability to form biofilms. Developing novel nanoformulations capable of inhibiting and removing biofilms offers a promising solution for controlling biofilm-related infections. In this study, we investigated the anti-biofilm activity of rutin-conjugated ZnO nanoparticles (ZnO-Rutin NPs) in pathogenic strains of P. aeruginosa. The synthesized ZnO-Rutin NPs had amorphous shapes with sizes ranging from 14 to 100 nm. The broth microdilution assay revealed that ZnO-Rutin NPs, with an MIC value of 2 mg/mL, exhibit greater antimicrobial activity than ZnO NPs and rutin alone. Based on crystal violet staining, the biofilm inhibition rate by ½ MIC of the conjugated nanoparticles was recorded at above 90%. The significant reduction in exopolysaccharide (62.75–66.37%) and alginate (38.3–57.61%) levels, as well as the formation of thin biofilms in the ZnO-Rutin NP-treated group, confirmed the anti-biofilm potential of these nanoparticles. Additionally, a significant decrease in the metabolic activity and viable cells of mature biofilms was observed after exposure to the conjugated nanoparticles. Furthermore, ZnO-Rutin NPs considerably attenuated the expression of the Las-Rhl quorum-sensing transcriptional regulator genes (lasR and rhlR) in P. aeruginosa by 0.39–0.40 and 0.25–0.42 folds, respectively. This work demonstrated that ZnO-Rutin NPs are remarkably capable of inhibiting the initial stage of biofilm formation and eradicating mature biofilms, suggesting they could be a useful agent for treating P. aeruginosa biofilm-related infections.

Taxonomical, phytochemical, antioxidant and antibacterial study of some medicinal plants of the Myrtaceae family

This paper addresses a comparative study of three medicinal plants of the myrtle family (Callistemon macropunctatus Dum. Cours. Court; Eucalyptus camaldulensis Dehnh.; Myrtus communis L.). The morphological characteristics of the pollen grains and some anatomical characteristics of the leaves and stems were evaluated, with quantitative estimates of the phenolic and flavonoid compounds of the leaves and determination of the efficacy of the aqueous-alcoholic extract of the leaves as an antioxidant based on the DPPH method; in addition, the efficacy of the extract as an antibacterial for some pathogenic strains, Gram-positive (Staphylococcus aureus and Klebsiella pneumonia) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) was evaluated. The results showed the taxonomic importance of pollen grain characteristics in separating the Myrtus communis species and the effective role of anatomical characteristics in separating the studied genera. Furthermore, the study's results showed the efficacy of the leaf extract of the studied genera as a strong antioxidant and an effective antibacterial for both types of pathogenic bacterial strains. The greatest efficacy of the extract was for the leaves of the Myrtus communis species due to the high content of phenolic compounds and flavonoids.

The interaction of Serratia bacteria and harmonine in harlequin ladybird confers an interspecies competitive edge

The harlequin ladybird, Harmonia axyridis, is a predatory beetle used globally to control pests such as aphids and scale insects. Originating from East Asia, this species has become highly invasive since its introduction in the late 19th century to Europe and North America, posing a threat to local biodiversity. Intraguild predation is hypothesized to drive the success of this invasive species, but the underlying mechanisms remain unknown. In this study, a feeding assay revealed that while harlequin ladybirds survive feeding on seven-spotted ladybird eggs, the reverse is not true. However, seven-spotted ladybirds that had fed on harlequin ladybird eggs were able to survive the feeding assay when treated with penicillin. Microbiome sequencing and whole genome analysis of harlequin ladybird eggs revealed a newly discovered pathogenic bacterium strain named Serratia harmoniae. The median lethal concentration (LC50) of S. harmoniae was found to be 2.1 × 105 times higher in the harlequin ladybird compared to the seven-spotted ladybird. The high tolerance observed in harlequin ladybirds was attributed to harmonine, specifically produced in the fat body of this species. Silencing three key genes in the harmonine biosynthesis pathway-Spidey, Sca2, and Desat-reduced the production of the compound, leading to increased S. harmoniae levels and higher mortality. Treating RNAi-altered individuals with penicillin reversed this effect, successfully reducing S. harmoniae presence and increasing insect survival. Taken together, these findings demonstrate that S. harmoniae, a newly identified pathogenic bacterium carried by harlequin ladybirds, interacts with harmonine to confer an interspecies competitive advantage over native ladybird species in nonnative regions.

You Win Some, You Lose Some: Modifying the Molecular Periphery of Nitrofuran-Tagged Diazaspirooctane Reshapes Its Antibacterial Activity Profile.

The use of the concept of privileged structures significantly accelerates the search for new leads and their optimization. 6-(methylsulfonyl)-8-(4-methyl-4H-1,2,4-triazol-3-yl)-2-(5-nitro-2-furoyl)-2,6-diazaspiro[3.4]octane 1 has been identified as a lead, with MICs of 0.0124-0.0441 μg/mL against MTb multiresistant strains. Several series of structural analogues have been synthesized, including variations in the periphery and simplifications of their scaffolds. All synthesized compounds were tested against the MTb H37Rv strain and ESKAPE panel of pathogens using serial broth dilutions. However, an attempt to optimize structure of 1 did not lead to the development of more active compounds which can work against MTb, but to substances with high activity against S. aureus. Induced-fit docking and MM-GBSA calculations determined a change in the likely biotarget from deazaflavin-dependent nitroreductase to azoreductases. The privileged nature of the scaffold was demonstrated by the detection of a different type of activity.

Design, Synthesis and Biological Evaluation of Ethyl 5-(1-benzyl-1H-indol-5-yl) Isoxazole-3-Carboxylates as Antimycobacterial Agents.

The continued prevalence of drug-resistant Mycobacterium tuberculosis (Mtb) strains, particularly against first-line antitubercular (anti-TB) drugs, presents an impending public health threat that necessitates the exploration and development of New Chemical Entities (NCEs). In search of new anti-TB leads, a library of ethyl 5-(1-benzyl-1H-indol-5-yl) isoxazole-3-carboxylates were generated through a strategy of scaffold hopping from the proven isoxazole-3-carboxylate-based anti-TB pharmacophore. We evaluated their antibacterial potential against a panel of pathogenic bacteria and Mtb H37Rv strains. The majority of the compounds exhibited notable in vitro efficacy against the H37Rv strains (MIC 0.25 to 16 μg/mL) and were not cytotoxic with a Selectivity Index (SI) >10. Compound 5e (3,4-dichlorobenzyl substituent) was found to be optimally active in the lot (MIC 0.25 μg/mL) and SI >200. It also displayed equipotent activity against drug-resistant Mtb (DR-Mtb) strains. In addition, it demonstrated concentration-dependent bactericidal activity in a time-kill kinetic assay similar to first-line anti-TB drugs besides exhibiting synergistic activity with Streptomycin. Moreover, it complies with the drug-likeness characteristic, making it a promising candidate for further exploration as a probable anti-TB lead.

Green synthesis of silver nanoparticles from endophytic fungus Colletotrichum sp. with special emphasis on antibacterial, antioxidant and plant growth promoting potential

The creation of "microbial nanotechnology" for quick and large-scale manufacturing of nanoparticles would be possible with an effective biosynthesis method. Plumbago zeylanica L. is a medicinal plant from which the endophytic fungus Colletotrichum sp. was isolated and identified by 18S rDNA sequencing and microscopic studies. Cell filtrate of Colletotrichum sp. was employed to produce biological silver nanoparticles which acted as a reducing and stabilising agent during this process. The brown colour proved that silver nanoparticles (AgNPs) are being produced. In characterization of AgNPs, ultraviolet-visible spectroscopy revealed maximum absorption at 425 nm. From transmission electron microscopy and field emission scanning electron microscopic study the shape of the silver nanoparticle was found spherical with 10–30 nm diameters. The existence of elemental silver (peak) was verified by the silver signal in the energy-dispersive X?ray spectroscopy. Fourier-transform infrared analysis showed some major and minor shifts in the peaks of some chemical bonding. Synthesised AgNP had strong antibacterial action against pathogenic bacterial strains in 200 g/mL concentration and against Pseudomonas aeruginosa MTCC 741, it showed the highest inhibition. The AgNP concentration of 150 g/mL demonstrated the highest competency for antioxidant capabilities while ascorbic acid was used as the reference. Also, AgNP exhibited plant growth-promoting ability as in 40 mg/L concentration; it significantly enhanced the shoot and root growth, total soluble protein, sugar, and indole acetic acid content of P. zeylanica L. This AgNP can be useful in pharmaceutical industries and agriculture as nano fertilizers for all these purposes.