Folia microbiologica最新文献

Lyme arthritis, one of the possible late manifestations of Lyme borreliosis, predominantly affects the supporting joints and in adults most often occurs in the form of monoarthritis of the knee. Early diagnosis is based on clinical findings and serology. PCR detection of Borrelia in synovial fluid has become an integral part of the laboratory testing algorithm. The clinical presentation and inflammatory markers in Lyme arthritis can resemble septic arthritis. Determining the levels of alpha-defensins (human neutrophil peptide (HNP 1-3)) in synovial fluid by liquid chromatography is a highly sensitive method revealing the presence of inflammatory process. Between 2020 and 2022, we examined eleven patients with Lyme arthritis of the knee. We measured levels of HNP 1-3 from synovial fluid by HPLC in patients, and we compared it with the corresponding C-reactive protein (CRP) levels in paired serum samples. In patients diagnosed with Lyme arthritis, HNP 1-3 levels in synovial fluid ranged from 2.5 to 261 mg/L, with a median of 46.5 mg/L. Average serum CRP was 43 mg/L. The results show that elevated HNP 1-3 can be consistent with not only septic arthritis or systemic disease, but also with Lyme arthritis, especially in patients with negative culture and 16S PCR from synovial fluid. Final diagnosis must be verified by examination for anti-Borrelia antibodies from serum and synovial fluid. The aim of this work is to introduce an HPLC method for the determination of alpha-defensins as one of the possible diagnostic markers.

There is an increasing demand for bioinoculants based on plant growth-promoting rhizobacteria (PGPR) for use in agricultural ecosystems. However, there are still concerns and limited data on their reproducibility in different soil types and their effects on endemic rhizosphere communities. Therefore, this study explored the effects of inoculating the PGPR, Pseudomonas fluorescens strain UM270, on maize growth (Zea mays L.) and its associated rhizosphere bacteriome by sequencing the 16S ribosomal genes under greenhouse conditions. The results showed that inoculation with PGPR P. fluorescens UM270 improved shoot and root dry weights, chlorophyll concentration, and total biomass in the three soil types evaluated (clay, sandy-loam, and loam) compared to those of the controls. Bacterial community analysis of the three soil types revealed that maize plants inoculated with the UM270 strain showed a significant increase in Proteobacteria and Acidobacteria populations, whereas Actinobacteria and Bacteroidetes decreased. Shannon, Pielou, and Faith alpha-biodiversity indices did not reveal significant differences between treatments. Beta diversity revealed a bacterial community differential structure in each soil type, with some variation among treatments. Finally, some bacterial groups were found to co-occur and co-exclude with respect to UM270 inoculation. Considered together, these results show that PGPR P. fluorescens UM270 increases maize plant growth and has an important effect on the resident rhizobacterial communities of each soil type, making it a potential agricultural biofertilizer.

Biofilm formation by the pathogenic bacteria generates a serious threat to the public health as it can increase the virulence potential, resistance to drugs, and escape from the host immune response mechanisms. Among the environmental factors that influence the biofilm formation, there are only limited reports available on the role of antimicrobial agents. During the antimicrobial drug administration or application for any purpose, the microbial population can expect to get exposed to the sub-minimum inhibitory concentration (sub-MIC) of the drug which will have an unprecedented impact on microbial responses. Hence, the study has been conducted to investigate the effects of sub-MIC levels of zinc oxide nanoparticles (ZnO NPs) on the biofilm formation of Klebsiella pneumoniae and Staphylococcus aureus. Here, the selected bacteria were primarily screened for the biofilm formation by using the Congo red agar method, and their susceptibility to ZnO NPs was also evaluated. Quantitative difference in biofilm formation by the selected organisms in the presence of ZnO NPs at the sub-MIC level was further carried out by using the microtiter plate-crystal violet assay. Further, the samples were subjected to atomic force microscopy (AFM) analysis to evaluate the properties and pattern of the biofilm modulated under the experimental conditions used. From these, the organisms treated with sub-MIC levels of ZnO NPs were found to have enhanced biofilm formation when compared with the untreated sample. Also, no microbial growth could be observed for the samples treated with the minimum inhibitory concentration (MIC) of ZnO NPs. The results observed in the study provide key insights into the impact of nanomaterials on clinically important microorganisms which demands critical thinking on the antimicrobial use of nanomaterials.

The diverse environmental distribution of Salmonella makes it a global source of human gastrointestinal infections. This study aimed to detect Salmonella spp. and explore their diversity and antimicrobial susceptibility patterns in clinical and environmental samples. Pre-enrichment, selective enrichment, and selective plating techniques were adopted for the Salmonella detection whereas the API 20E test and Vitek Compact 2 system were used to confirm the identity of isolates. Salmonella serovars were subjected to molecular confirmation by 16S rDNA gene sequencing. Disc diffusion method and Vitek 2 Compact system determined the antibiotic susceptibility of Salmonella serovars. Multiple antibiotic resistance index (MARI) was calculated to explore whether Salmonella serovars originate from areas with heavy antibiotic usage. Results depicted low Salmonella prevalence in clinical and environmental samples (3.5%). The main detected serovars included Salmonella Typhimurium, S. enteritidis, S. Infantis, S. Newlands, S. Heidelberg, S. Indian, S. Reading, and S. paratyphi C. All the detected Salmonella serovars (27) exhibited multidrug resistance to three or more antimicrobial classes. The study concludes that the overall Salmonella serovars prevalence was found to be low in environmental and clinical samples of Western Saudi Arabia (Makkah and Jeddah). However, antimicrobial susceptibility patterns of human and environmental Salmonella serovars revealed that all isolates exhibited multidrug-resistance (MDR) patterns to frequently used antibiotics, which might reflect antibiotic overuse in clinical and veterinary medicine. It would be suitable to apply and enforce rules and regulations from the One Health approach, which aim to prevent antibiotic resistance infections, enhance food safety, and improve human and animal health, given that all Salmonella spp. detected in this investigation were exhibiting MDR patterns.

Microbial colonization on the titanium condenser material (TCM) used in the cooling system leads to biofouling and corrosion and influences the water supply. The primary investigation of the titanium condenser was infrequently studied on characterizing biofilm-forming bacterial communities. Different treatment methods like electropotential charge, ultrasonication, and copper coating of titanium condenser material may influence the microbial population over the surface of the titanium condensers. The present study aimed to catalog the primary colonizers and the effect of different treatment methods on the microbial community. CFU (1.7 × 10⁹ CFU/mL) and ATP count (< 5000 × 10^-7 relative luminescence units) showed a minimal microbial population in copper-coated surface biofilm as compared with the other treatments. Live and dead cell result also showed consistency with colony count. The biofilm sample on the copper-coated surface showed an increased dead cell count and decreased live cells. In the metagenomic approach, the microbiome coverage was 10.06 Mb in samples derived from copper-coated TCM than in other treated samples (electropotential charge-17.94 Mb; ultrasonication-20.01 Mb), including control (10.18 Mb). Firmicutes preponderate the communities in the biofilm samples, and Proteobacteria stand next in the population in all the treated condenser materials. At the genus level, Lactobacillaceae and Azospirillaceae dominated the biofilm community. The metagenome data suggested that the attached community is different from those biofilm samples based on the environment that influences the bacterial community. The outcome of the present study depicts that copper coating was effective against biofouling and corrosion resistance of titanium condenser material for designing long-term durability.

Helicobacter pylori colonizes the human gastric mucosa of more than half of the human population and has a unique lipopolysaccharide (LPS) structure. LPS is the most dominant and suitable pathogen-associated molecular pattern that is detected via pattern recognition receptors. Although the priming effect of H. pylori LPS on reactive oxygen species (ROS) production of PMNs is lower than that of Escherichia coli O111:B4 LPS, LPS released from H. pylori associated with antibiotics eradication therapy may activate PMNs and increase ROS production. In addition, we describe the effects of H. pylori and E. coli O111:B4 LPSs on gene expression and the anti-inflammatory effect of lansoprazole (LPZ) in human polymorphonuclear leukocytes. LPS isolated from H. pylori and E. coli O111:B4 alters toll-like receptor 2 (TLR) and TLR4 expressions similarly. However, LPS from E. coli O111:B4 and H. pylori caused a 1.8-fold and 1.5-fold increase, respectively, in CD14 expression. All LPS subtypes upregulated TNFα and IL6 expression in a concentration-dependent manner. Although E. coli O111:B4 LPS upregulated IL8R mRNA levels, H. pylori LPS did not (≦ 100 ng/mL). Gene expression levels of ITGAM demonstrated no significant change on using both LPSs. These different effects on the gene expression in PMNs may depend on variations in LPS structural modifications related to the acquired immunomodulatory properties of H. pylori LPS. Proton pump inhibitors, i.e., LPZ, are used in combination with antibiotics for the eradication therapy of H. pylori. LPZ and its acid-activated sulphenamide form AG-2000 suppress ROS production of PMNs in a dose-dependent manner. These results suggest that LPZ combination with antibiotics for H. pylori eradication reduces gastric inflammation by suppressing ROS release from PMNs.

Nitrogen, phosphorus, and potassium are the three most essential micronutrients which play major roles in plant survivability by being a structural or non-structural component of the cell. Plants acquire these nutrients from soil in the fixed (NO₃^¯, NH₄⁺) and solubilized forms (K⁺, H₂PO₄^- and HPO₄^2-). In soil, the fixed and solubilized forms of nutrients are unavailable or available in bare minimum amounts; therefore, agrochemicals were introduced. Agrochemicals, mined from the deposits or chemically prepared, have been widely used in the agricultural farms over the decades for the sake of higher production of the crops. The excessive use of agrochemicals has been found to be deleterious for humans, as well as the environment. In the environment, agrochemical usage resulted in soil acidification, disturbance of microbial ecology, and eutrophication of aquatic and terrestrial ecosystems. A solution to such devastating agro-input was found to be substituted by macronutrients-availing microbiomes. Macronutrients-availing microbiomes solubilize and fix the insoluble form of nutrients and convert them into soluble forms without causing any significant harm to the environment. Microbes convert the insoluble form to the soluble form of macronutrients (nitrogen, phosphorus, and potassium) through different mechanisms such as fixation, solubilization, and chelation. The microbiomes having capability of fixing and solubilizing nutrients contain some specific genes which have been reported in diverse microbial species surviving in different niches. In the present review, the biodiversity, mechanism of action, and genomics of different macronutrients-availing microbiomes are presented.

The diversity of cultivable endophytic fungi in native subshrubs of the Brazilian Cerrado is largely unknown. This study investigated the cultivable endophytic mycobiome of stems, leaves, and flowers of Peltaea polymorpha (Malvaceae). In total, 208 endophytic fungi were isolated, 95 from stems, 65 from leaves, and 48 from flowers. The isolates were classified as ascomycetes belonging to three classes, eight orders, ten families, 12 genera, and 31 species. Diaporthe, Nigrospora, and Colletotrichum were the dominant genera in the three analyzed organs. The richness estimators suggested that the number of species might be slightly higher than observed. The highest values for the Shannon and Simpson diversity indices were observed in stems. Beta diversity showed overlapping of fungal communities in different organs, with a high rate of sharing of taxa. Furthermore, the dominant primary fungal lifestyles were plant pathogens and saprobes. Our findings show that the cultivable endophytic fungal community of P. polymorpha is species-rich and that communities in different organs share genera and species.

In screening biocontrol strains with broad-spectrum and high-efficiency herbicidal activities, a strain with strong pathogenicity, HY-021, was isolated from the leaves of Rumex acetosa, which was identified as Botrytis fabiopsis based on morphology and molecular biology. The herbicidal activities of the fermentation filtrate of strain HY-021 against nine weeds, including Chenopodium album L., Elsholtzia densa Benth., Malva verticillata L. var. Crispa, Polygonum lapathifolium L., Amaranthus retroflexus L., Avena fatua L., Thlaspi arvense L., Polygonum aviculare L., and Galium spurium L., were determined in vitro and in vivo. The results showed that the pathogenicity of strain HY-021 to the different weeds in vitro was as follows: E. densa > A. retroflexus > P. aviculare > P. lapathifolium > M. verticillata > T. arvense > G. spurium > A. fatua > C. album. Seven days after inoculation with the HY-021 strain, the incidences in nine weeds were in the range of 32.9-87.23%, and the disease index values of the nine weeds were 41.73-94.57%. The pathogenic effects from high to low were A. retroflexus > E. densa > A. fatua > G. spurium > C. album > M. verticillata > T. arvense > P. aviculare > P. lapathifolium. The crop safety test showed that the biocontrol strain HY-021 was safe to V. faba, P. sativum, H. vulgare, and T. aestivum, but had a slight effect on B. napus. Scanning electron microscopy showed that the mycelium of strain HY-021 invaded the tissue through the stomata of C. album leaves, parasitized and reproduced in the tissue, and gradually destroyed the tissue. The results of this study provide a basis for the development and utilization of new and efficient microbial source herbicides.

Bacterial resistance has become a global concern for public health agencies. Various resistance mechanisms found in Staphylococcus aureus strains grant this bacterium resistance to a wide range of antibiotics, contributing to the rise in human mortality worldwide. Resistance mediated by efflux pumps is one of the most prevalent mechanisms in multi-resistant bacteria, which has aroused the interest of several researchers in the search for possible efflux pump inhibitors. In view of the aforementioned considerations, it is important that new strategies, such as the synthesis of chalcones, be made available as a viable strategy in antimicrobial therapy. In this study, the synthesized chalcone (2E)-1-(3'-aminophenyl)-3-(4-dimethylaminophenyl)-prop-2-en-1-one was tested for its antibacterial activity, focusing on antibiotic modification and the inhibition of the MepA efflux pump present in S. aureus strain K2068. The broth microdilution method, using microdilution plates, was employed in microbiological tests to determine the minimum inhibitory concentration of the chalcone, antibiotics, and ethidium bromide. The results show that while the chalcone did not exhibit direct antibacterial activity, it synergistically enhanced the effects of ciprofloxacin and ethidium bromide, as evidenced by the reduction in MICs. In addition, computer simulations of molecular docking demonstrate that the tested chalcone acts on the same binding site as the efflux pump inhibitor chlorpromazine, interacting with essentially the same residues. These data suggest that the chalcone may act as a MepA inhibitor.