MicrobiologyOpen最新文献

Hexachlorocyclohexane (HCH) was extensively used as a pesticide until the 1990s. It was synthesized by benzene photochlorination, resulting in a mixture of stereoisomers, which included α-, β-, γ-, and δ-HCH, among others. It was later discovered that only the γ-HCH isomer (also called lindane) had insecticidal properties, so it began to be purified from this mixture, while the remaining HCH isomers (representing around 85%–90% of industrial HCH production) were disposed of in dumpsites, generating environmental issues. Several works have studied microbial-driven biodegradation and physiological responses to γ-HCH, but information concerning the other isomers is scarce. Since previous research showed that the cyanobacterium Anabaena sp. PCC 7120 is effective at removing lindane; this study focused on its responses to the α-, β-, and δ-HCH isomers. The results showed that Anabaena tolerates α- and γ-HCH well, with little impact on growth, while β- and δ-HCH are more poorly tolerated and negatively affect growth and cell physiology. It was also found that, in the presence of Anabaena sp. PCC 7120, both α- and γ-HCH are completely eliminated from supernatants while β- and δ-HCH are partially eliminated. Additionally, the linC gene was found to be expressed at twice the normal level in the presence of α- and γ-HCH at 2 mg/mL. Overall, this study reveals how Anabaena responds to key HCH isomers found in contaminated sites and supports its potential use in bioremediation.

The research aimed at investigating the antibacterial potential of dental resin composites when combined with various antimicrobial peptides (AMPs) against Porphyromonas gingivalis heme-binding proteins, which are associated with biofilm-related infections in restorative dentistry. A multistage computational approach was implemented to assess the AMP interactions. Molecular docking analyses demonstrated the promising binding of resin constituents with AMPs, and Pardaxin exhibited the highest binding affinity, followed by Tachystatin and Thermolysin. The best performing AMPs were then docked with P. gingivalis heme-binding proteins, and the complexes were subjected to 100 ns molecular dynamics simulations for stability assessment. The simulations confirmed stable interactions, while MM/PBSA binding energy calculations demonstrated significant binding strengths, particularly for Pardaxin (ΔG = −65.58 kcal/mol) and Tachystatin (ΔG = −48.71 kcal/mol), with Thermolysin also showing promising results (ΔG = −39.92 kcal/mol). The comprehensive analysis indicates the potential of incorporating Pardaxin, Tachystatin, and Thermolysin into dental resin composites to enhance their antibacterial activity against P. gingivalis. However, the study is limited to in silico assessments and relies on static representations of resin monomers that may not accurately represent the biological and clinical environment. Experimental validation through in vitro and in vivo studies, including cytocompatibility testing, peptide release behavior, and long-term mechanical stability, is essential to establish their practical application in restorative dentistry.

Supplementing H. pylori treatment with probiotics like Lactobacillus has become an essential approach due to the possible adverse effects of antibiotic therapy and the need to increase overall eradication rates. Although several types of Lactobacillus strains as probiotics were efficient in treating H. pylori, their relative efficiency in treating H. pylori was uncertain. A survey of databases, including PubMed, Cochrane, Google Scholar, Scopus, and Clinicaltrials.gov, retrieved 52 Randomized Controlled Trials (RCTs), with 14 meeting the criteria for RCTs on Lactobacillus supplementation (LS) as an adjunct therapy compared to placebo in adult H. pylori patients. Analyses were conducted using RevMan5.3, Cochrane Risk of Bias Tool, Comprehensive Meta-Analysis Software, and GRADEpro. Fourteen RCTs, including 2054 patients with more than ten different probiotics, were included in this analysis. The LS group showed significantly higher H. pylori eradication rates [RR = 1.04 (95% CI: 1.01, 1.07; p = 0.009; I² = 0%); (high certainty)], decreased AEs including vomiting [RR = 0.82 (95% CI: 0.48, 1.41; p = 0.48; I² = 19%); (high certainty)], diarrhea [RR = 0.45 (95% CI: 0.26, 0.80; p = 0.007; I² = 55%); (high certainty)], abdominal pain [RR = 0.73 (95% CI: 0.28, 1.93; p = 0.53; I² = 66%); (high certainty)], anorexia [RR = 0.79 (95% CI: 0.23, 2.64; p = 0.70; I² = 0%); (high certainty)], constipation [RR = 1.02 (95% CI: 0.42, 2.50; p = 0.96; I² = 0%); (high certainty)], rash [RR = 1.51 (95% CI: 0.57, 3.98; p = 0.41; I² = 0%); (high certainty)], taste disturbance [RR = 0.64 (95% CI: 0.44, 0.92; p = 0.02; I² = 51%); (moderate certainty)], and reduction of gastrointestinal symptoms including abdominal pain [SMD = −0.19 (95% CI: −0.46, 0.09; p = 0.18; I² = %); (moderate certainty)]. None of the included RCTs depicted a high risk of bias. Lactobacillus added to triple or quadruple therapy increased eradication rates, but improvements in adverse effects and gastrointestinal symptoms were not significant. Multiple different strains limited assessment of individual effectiveness, preventing firm conclusions about the specific impact of each Lactobacillus type.

Campylobacter species, a major cause of gastroenteritis, have been frequently isolated from wild birds. Here we determined the prevalence of Campylobacter in wild birds from Switzerland. Campylobacter isolates were then further characterized by whole genome sequencing. A total of 154 samples from 27 different wild bird species were analyzed and Campylobacter was detected in 23 samples (14.9%). Twenty-one isolates were identified as C. jejuni, one as C. coli and one isolate likely belongs to a novel species. Whole genome analyses revealed that the strains were diverse, belonging to 17 different sequence types. Antimicrobial resistances of the C. jejuni strains included class D ß-lactamase bla_OXA genes in all isolates, T86I mutations in GyrA conferring resistance to quinolones in 7 isolates, and tet(O) in 3 isolates. A comparison to 787 Campylobacter from various sources in Switzerland showed that strains spread between humans, poultry and wild birds. Moreover, plasmid analyses and genome comparison provided a strong indication of horizontal gene transfer between Campylobacter strains. Our results strongly support a One-Health approach that includes wild animals to understand and control epidemiology of Campylobacter.

Activating cryptic secondary metabolic gene clusters is a critical area of research in Streptomyces, and the cultivation-based approach is one of effective ways to induce the expression of cryptic gene clusters. In this study, the oligotrophic medium and modified Gauze's medium were used to culture the marine Streptomyces sp. FJNU027 strain, and a unique secondary metabolite in oligotrophic culture was found by HPLC assay when compared with the modified Gauze's culture. Then the differential product was isolated through large-scale fermentation, solvent extraction, column chromatography over Sephadex LH-20, and HPLC preparation. The pure differential product was analyzed by NMR and LC-MS, and identified as 4,4′,5,5′-tetramethyl-[1,1′- diphenyl]-2,2′-diol. To elucidate the possible biosynthesis mechanism of the differential product, the transcriptome sequencing was performed. It showed the expressions of polyketide synthase gene (FZ01GL006410) and cytochrome P450 gene (FZ01GL006417) were significantly enhanced in the oligotrophic medium, and these two genes might be responsible for the biosynthesis of the differential product. This compound was reported for the first time isolated from a natural source, demonstrating a novel approach for acquiring this type of compound. The results indicate that oligotrophic culture is an effective method for modulating the secondary metabolism of Streptomyces.

Salmonella is recognized as one of the foodborne bacterial infections. The bacterium spreads through contact with animals and ingestion of contaminated foods. This study aimed to determine the prevalence, risk factors, and antimicrobial susceptibility patterns of Salmonella from bulk milk at dairy farm level in Mekelle and Southeast Zones of Tigrai, Ethiopia. A cross-sectional study was carried out from January to June 2025. After taking the consent, sociodemographic, risk factors, and 203 bulk milk samples were collected from the dairy farms. Salmonella was isolated and identified through pre-enrichment, selective enrichment, selective media, and a series of biochemical tests. Antimicrobial susceptibility testing was conducted using the disk diffusion method. Stata v-16 was employed to determine the strength of the factors that associates with Salmonella. The prevalence of Salmonella was six (2.96%). Salmonella positivity showed statistically significant association with farms that don't practice regular udder washing before milking, lack of knowledge about bacterial infections, and do not know that consumption of raw milk cause foodborne illness. Five (83.3%) isolates of Salmonella showed resistance to ampicillin and tetracycline, and four (66.7%) to streptomycin. All Salmonella isolates were susceptible to ceftazidime and cefotaxime. Three isolates of Salmonella showed multidrug resistance. The prevalence of Salmonella was low, but its presence in milk may be considered a potential risk to milk safety. Three Salmonella isolates showed resistance to four and six antimicrobial classes. The finding highlights the need for appropriate hygiene practices and the correct use of antibiotics in the farms.

Olive pomace (OP) is a sludge arising from the production of olive oil, generated in increasing amounts in Portugal. The management of this toxic waste stream is complex and the number of processing plants is limited. In this study, OP was incorporated as a feed component for rearing black soldier fly larvae (BSFL) under industrial conditions. Larvae were reared inside a climate-controlled room with regulated temperature and humidity. The rearing cycle lasted 13 days, after which larvae were harvested. In addition to assessing bioconversion efficiency and larval proximate composition, the resulting frass was examined for its fertilizer potential. Frass was analyzed for plant nutrient content and microbial profile in three forms: fresh, heat-treated (70°C for 1 h), and pelletized. The inclusion of OP in the diets reduced waste-to-biomass conversion efficiency (21.5%_DM to approximately 13.3%_DM) but did not affect the proximate composition of the larval biomass, which consistently contained around 43%_DM crude protein and 20%_DM crude fat. Neither the presence of OP nor the applied post-treatments altered the nutrient composition of frass, which contained on average 3.5% total N, 2.6% P₂O₅, and 5.9% K₂O. However, at the highest inclusion level (84%), the abundance of bacterial and fungal groups was significantly reduced. The predominant phyla in the frass were Actinobacteria, Bacteroidota, Firmicutes, Proteobacteria, Ascomycota and Basidiomycota, and the dynamics of microbial communities were influenced by specific micronutrients. The presence of OP led to a significant reduction of potentially pathogenic bacteria and fungi in the frass, indicating a sanitizing effect attributable to this material.

Emerging evidence suggests that OBSCN, a giant cytoskeletal protein gene, plays multifaceted roles in cancer progression, yet its impact on gastric cancer (GC) remains poorly understood. Through integrative analysis of multi-omics datasets, we observe a close relationship between OBSCN expression and outcome of immunotherapy. Besides, elevated expression of OBSCN strongly associated with adverse disease free survival (DFS). Tumor-resident microbes, such as Fusobacterium, can impact the expression of microRNAs (miRNAs) targeting OBSCN. In terms of genomic alterations, mutational status of OBSCN is substantially associated with the alpha- and beta-diversity of intratumoral microbiome and patients with mutated OBSCN exhibit elevated higher tumor mutational burden (TMB) and better response to immunotherapy. Furthermore, machine learning models based on the OBSCN mutation-related gene signatures (OMRGS) achieve outstanding performance in prediction of response to immune checkpoint inhibitors. In summary, our findings position OBSCN as a novel molecular nexus linking genomic alterations, intratumoral microbiome dysbiosis, and immune infiltration in GC, providing a rationale for future biomarker-driven therapeutic strategies.

The rise in azole resistance among Nakaseomyces glabratus and Pichia kudriavzevii in recurrent vulvovaginal candidiasis presents a growing public health challenge. This study investigated the expression of antifungal resistance-related genes (ERG11, CDR1, CDR2, and MDR1) in clinical resistant (CR) and clinical and laboratory resistant (CLR) strains of these yeasts. Cervicovaginal samples from patients with recurrent infections were collected, microscopically examined, and cultured. Yeast species were identified phenotypically and genotypically, followed by drug sensitivity testing. Total RNA was extracted, reverse transcribed to complementary DNA, and real-time polymerase chain reaction was used to quantify target gene expression, comparing results to drug-sensitive controls. Non-Candida albicans species constituted 29% (45 cases) of the isolates, with N. glabratus (68%) and P. kudriavzevii (17%) being the dominant species. Other species included Candida parapsilosis, Meyerozyma guilliermondii, Candida orthopsilosis, Saccharomyces cerevisiae, and Rhodotorula mucilaginosa. Coinfections with P. kudriavzevii/C. albicans and N. glabratus/C. albicans were also observed. Ketoconazole, itraconazole, and 5-flucytosine demonstrated the best antifungal activity against most species. However, some N. glabratus isolates were resistant to miconazole, clotrimazole, and amphotericin B, while all P. kudriavzevii isolates resisted clotrimazole. Overexpression of the CDR1 gene was noted in N. glabratus (CR, 21.53 ± 1.26; CLR, 84.96 ± 0.67), and the ERG11 and CDR1 genes in P. kudriavzevii (ERG11 for CR, 28.56 ± 2.16; CDR1 for CLR, 35.89 ± 0.35). These results indicate that even in cases where an isolate is classified as susceptible by drug susceptibility testing, elevated gene expression may persist, and treatment should not be discontinued.

The emergence and dissemination of aquatic pathogens pose significant risks to farmed species. Francisella halioticida, initially reported in abalones and Yesso scallops, was recently isolated from mussels in France, with some isolates showing high virulence. This study aimed to characterize and compare several F. halioticida isolates from mussels using phenotypic and genotypic approaches. Phenotypic analysis was performed using growth curves, biochemical profiles (API strips), and morphology assessed by electron microscopy. Genetic analysis has been performed through whole-genome comparison using classification methods and virulence markers seeking. Phenotypic analyses highlighted similarities among FR22 isolates and notable differences with FR21 and AG1. Notably, AG1 displayed distinct features. Antibiotic resistance profiling revealed the species' capacity to withstand multiple antimicrobial agents with various modes of action. Complete, circular genomes were assembled and compared using targeted and untargeted approaches. These analyses confirmed the affiliation of FR22 isolates with the F. halioticida species, while FR21 and AG1 taxonomy need to be further investigated. Virulence factor screening revealed the presence of secretion system components (types I, IV, and VI) in all isolates. A novel variant of the Francisella Pathogenicity Island (FPI) was described, shared by all virulent isolates. However, this FPI was absent in the low virulence isolate FR22b. In conclusion, this study discriminates against F. halioticida isolates and proposes new hypotheses on their virulence, contributing to improved detection tools and expanding our understanding of this emerging aquatic pathogen.